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3301 lines
79 KiB
3301 lines
79 KiB
// SPDX-License-Identifier: GPL-2.0 |
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/* |
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* n_gsm.c GSM 0710 tty multiplexor |
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* Copyright (c) 2009/10 Intel Corporation |
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* |
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* * THIS IS A DEVELOPMENT SNAPSHOT IT IS NOT A FINAL RELEASE * |
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* |
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* TO DO: |
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* Mostly done: ioctls for setting modes/timing |
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* Partly done: hooks so you can pull off frames to non tty devs |
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* Restart DLCI 0 when it closes ? |
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* Improve the tx engine |
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* Resolve tx side locking by adding a queue_head and routing |
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* all control traffic via it |
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* General tidy/document |
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* Review the locking/move to refcounts more (mux now moved to an |
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* alloc/free model ready) |
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* Use newest tty open/close port helpers and install hooks |
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* What to do about power functions ? |
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* Termios setting and negotiation |
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* Do we need a 'which mux are you' ioctl to correlate mux and tty sets |
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* |
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*/ |
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|
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#include <linux/types.h> |
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#include <linux/major.h> |
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#include <linux/errno.h> |
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#include <linux/signal.h> |
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#include <linux/fcntl.h> |
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#include <linux/sched/signal.h> |
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#include <linux/interrupt.h> |
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#include <linux/tty.h> |
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#include <linux/ctype.h> |
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#include <linux/mm.h> |
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#include <linux/string.h> |
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#include <linux/slab.h> |
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#include <linux/poll.h> |
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#include <linux/bitops.h> |
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#include <linux/file.h> |
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#include <linux/uaccess.h> |
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#include <linux/module.h> |
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#include <linux/timer.h> |
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#include <linux/tty_flip.h> |
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#include <linux/tty_driver.h> |
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#include <linux/serial.h> |
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#include <linux/kfifo.h> |
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#include <linux/skbuff.h> |
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#include <net/arp.h> |
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#include <linux/ip.h> |
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#include <linux/netdevice.h> |
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#include <linux/etherdevice.h> |
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#include <linux/gsmmux.h> |
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#include "tty.h" |
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|
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static int debug; |
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module_param(debug, int, 0600); |
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|
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/* Defaults: these are from the specification */ |
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|
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#define T1 10 /* 100mS */ |
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#define T2 34 /* 333mS */ |
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#define N2 3 /* Retry 3 times */ |
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|
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/* Use long timers for testing at low speed with debug on */ |
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#ifdef DEBUG_TIMING |
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#define T1 100 |
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#define T2 200 |
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#endif |
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|
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/* |
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* Semi-arbitrary buffer size limits. 0710 is normally run with 32-64 byte |
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* limits so this is plenty |
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*/ |
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#define MAX_MRU 1500 |
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#define MAX_MTU 1500 |
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#define GSM_NET_TX_TIMEOUT (HZ*10) |
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|
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/* |
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* struct gsm_mux_net - network interface |
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* |
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* Created when net interface is initialized. |
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*/ |
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struct gsm_mux_net { |
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struct kref ref; |
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struct gsm_dlci *dlci; |
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}; |
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|
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/* |
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* Each block of data we have queued to go out is in the form of |
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* a gsm_msg which holds everything we need in a link layer independent |
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* format |
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*/ |
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struct gsm_msg { |
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struct list_head list; |
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u8 addr; /* DLCI address + flags */ |
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u8 ctrl; /* Control byte + flags */ |
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unsigned int len; /* Length of data block (can be zero) */ |
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unsigned char *data; /* Points into buffer but not at the start */ |
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unsigned char buffer[]; |
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}; |
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|
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enum gsm_dlci_state { |
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DLCI_CLOSED, |
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DLCI_OPENING, /* Sending SABM not seen UA */ |
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DLCI_OPEN, /* SABM/UA complete */ |
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DLCI_CLOSING, /* Sending DISC not seen UA/DM */ |
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}; |
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|
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enum gsm_dlci_mode { |
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DLCI_MODE_ABM, /* Normal Asynchronous Balanced Mode */ |
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DLCI_MODE_ADM, /* Asynchronous Disconnected Mode */ |
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}; |
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|
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/* |
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* Each active data link has a gsm_dlci structure associated which ties |
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* the link layer to an optional tty (if the tty side is open). To avoid |
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* complexity right now these are only ever freed up when the mux is |
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* shut down. |
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* |
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* At the moment we don't free DLCI objects until the mux is torn down |
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* this avoid object life time issues but might be worth review later. |
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*/ |
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|
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struct gsm_dlci { |
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struct gsm_mux *gsm; |
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int addr; |
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enum gsm_dlci_state state; |
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struct mutex mutex; |
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|
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/* Link layer */ |
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enum gsm_dlci_mode mode; |
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spinlock_t lock; /* Protects the internal state */ |
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struct timer_list t1; /* Retransmit timer for SABM and UA */ |
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int retries; |
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/* Uplink tty if active */ |
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struct tty_port port; /* The tty bound to this DLCI if there is one */ |
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struct kfifo fifo; /* Queue fifo for the DLCI */ |
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int adaption; /* Adaption layer in use */ |
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int prev_adaption; |
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u32 modem_rx; /* Our incoming virtual modem lines */ |
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u32 modem_tx; /* Our outgoing modem lines */ |
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bool dead; /* Refuse re-open */ |
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/* Flow control */ |
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bool throttled; /* Private copy of throttle state */ |
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bool constipated; /* Throttle status for outgoing */ |
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/* Packetised I/O */ |
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struct sk_buff *skb; /* Frame being sent */ |
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struct sk_buff_head skb_list; /* Queued frames */ |
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/* Data handling callback */ |
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void (*data)(struct gsm_dlci *dlci, const u8 *data, int len); |
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void (*prev_data)(struct gsm_dlci *dlci, const u8 *data, int len); |
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struct net_device *net; /* network interface, if created */ |
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}; |
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/* DLCI 0, 62/63 are special or reserved see gsmtty_open */ |
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|
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#define NUM_DLCI 64 |
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|
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/* |
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* DLCI 0 is used to pass control blocks out of band of the data |
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* flow (and with a higher link priority). One command can be outstanding |
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* at a time and we use this structure to manage them. They are created |
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* and destroyed by the user context, and updated by the receive paths |
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* and timers |
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*/ |
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struct gsm_control { |
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u8 cmd; /* Command we are issuing */ |
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u8 *data; /* Data for the command in case we retransmit */ |
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int len; /* Length of block for retransmission */ |
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int done; /* Done flag */ |
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int error; /* Error if any */ |
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}; |
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enum gsm_mux_state { |
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GSM_SEARCH, |
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GSM_START, |
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GSM_ADDRESS, |
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GSM_CONTROL, |
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GSM_LEN, |
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GSM_DATA, |
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GSM_FCS, |
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GSM_OVERRUN, |
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GSM_LEN0, |
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GSM_LEN1, |
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GSM_SSOF, |
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}; |
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|
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/* |
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* Each GSM mux we have is represented by this structure. If we are |
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* operating as an ldisc then we use this structure as our ldisc |
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* state. We need to sort out lifetimes and locking with respect |
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* to the gsm mux array. For now we don't free DLCI objects that |
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* have been instantiated until the mux itself is terminated. |
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* |
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* To consider further: tty open versus mux shutdown. |
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*/ |
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|
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struct gsm_mux { |
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struct tty_struct *tty; /* The tty our ldisc is bound to */ |
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spinlock_t lock; |
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struct mutex mutex; |
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unsigned int num; |
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struct kref ref; |
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|
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/* Events on the GSM channel */ |
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wait_queue_head_t event; |
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|
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/* Bits for GSM mode decoding */ |
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|
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/* Framing Layer */ |
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unsigned char *buf; |
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enum gsm_mux_state state; |
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unsigned int len; |
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unsigned int address; |
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unsigned int count; |
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bool escape; |
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int encoding; |
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u8 control; |
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u8 fcs; |
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u8 received_fcs; |
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u8 *txframe; /* TX framing buffer */ |
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|
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/* Method for the receiver side */ |
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void (*receive)(struct gsm_mux *gsm, u8 ch); |
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|
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/* Link Layer */ |
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unsigned int mru; |
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unsigned int mtu; |
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int initiator; /* Did we initiate connection */ |
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bool dead; /* Has the mux been shut down */ |
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struct gsm_dlci *dlci[NUM_DLCI]; |
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bool constipated; /* Asked by remote to shut up */ |
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|
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spinlock_t tx_lock; |
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unsigned int tx_bytes; /* TX data outstanding */ |
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#define TX_THRESH_HI 8192 |
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#define TX_THRESH_LO 2048 |
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struct list_head tx_list; /* Pending data packets */ |
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|
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/* Control messages */ |
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struct timer_list t2_timer; /* Retransmit timer for commands */ |
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int cretries; /* Command retry counter */ |
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struct gsm_control *pending_cmd;/* Our current pending command */ |
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spinlock_t control_lock; /* Protects the pending command */ |
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|
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/* Configuration */ |
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int adaption; /* 1 or 2 supported */ |
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u8 ftype; /* UI or UIH */ |
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int t1, t2; /* Timers in 1/100th of a sec */ |
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int n2; /* Retry count */ |
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|
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/* Statistics (not currently exposed) */ |
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unsigned long bad_fcs; |
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unsigned long malformed; |
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unsigned long io_error; |
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unsigned long bad_size; |
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unsigned long unsupported; |
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}; |
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/* |
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* Mux objects - needed so that we can translate a tty index into the |
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* relevant mux and DLCI. |
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*/ |
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#define MAX_MUX 4 /* 256 minors */ |
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static struct gsm_mux *gsm_mux[MAX_MUX]; /* GSM muxes */ |
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static DEFINE_SPINLOCK(gsm_mux_lock); |
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|
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static struct tty_driver *gsm_tty_driver; |
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|
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/* |
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* This section of the driver logic implements the GSM encodings |
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* both the basic and the 'advanced'. Reliable transport is not |
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* supported. |
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*/ |
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#define CR 0x02 |
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#define EA 0x01 |
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#define PF 0x10 |
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|
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/* I is special: the rest are ..*/ |
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#define RR 0x01 |
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#define UI 0x03 |
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#define RNR 0x05 |
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#define REJ 0x09 |
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#define DM 0x0F |
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#define SABM 0x2F |
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#define DISC 0x43 |
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#define UA 0x63 |
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#define UIH 0xEF |
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|
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/* Channel commands */ |
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#define CMD_NSC 0x09 |
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#define CMD_TEST 0x11 |
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#define CMD_PSC 0x21 |
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#define CMD_RLS 0x29 |
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#define CMD_FCOFF 0x31 |
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#define CMD_PN 0x41 |
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#define CMD_RPN 0x49 |
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#define CMD_FCON 0x51 |
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#define CMD_CLD 0x61 |
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#define CMD_SNC 0x69 |
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#define CMD_MSC 0x71 |
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/* Virtual modem bits */ |
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#define MDM_FC 0x01 |
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#define MDM_RTC 0x02 |
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#define MDM_RTR 0x04 |
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#define MDM_IC 0x20 |
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#define MDM_DV 0x40 |
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#define GSM0_SOF 0xF9 |
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#define GSM1_SOF 0x7E |
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#define GSM1_ESCAPE 0x7D |
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#define GSM1_ESCAPE_BITS 0x20 |
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#define XON 0x11 |
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#define XOFF 0x13 |
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static const struct tty_port_operations gsm_port_ops; |
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/* |
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* CRC table for GSM 0710 |
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*/ |
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static const u8 gsm_fcs8[256] = { |
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0x00, 0x91, 0xE3, 0x72, 0x07, 0x96, 0xE4, 0x75, |
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0x0E, 0x9F, 0xED, 0x7C, 0x09, 0x98, 0xEA, 0x7B, |
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0x1C, 0x8D, 0xFF, 0x6E, 0x1B, 0x8A, 0xF8, 0x69, |
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0x12, 0x83, 0xF1, 0x60, 0x15, 0x84, 0xF6, 0x67, |
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0x38, 0xA9, 0xDB, 0x4A, 0x3F, 0xAE, 0xDC, 0x4D, |
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0x36, 0xA7, 0xD5, 0x44, 0x31, 0xA0, 0xD2, 0x43, |
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0x24, 0xB5, 0xC7, 0x56, 0x23, 0xB2, 0xC0, 0x51, |
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0x2A, 0xBB, 0xC9, 0x58, 0x2D, 0xBC, 0xCE, 0x5F, |
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0x70, 0xE1, 0x93, 0x02, 0x77, 0xE6, 0x94, 0x05, |
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0x7E, 0xEF, 0x9D, 0x0C, 0x79, 0xE8, 0x9A, 0x0B, |
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0x6C, 0xFD, 0x8F, 0x1E, 0x6B, 0xFA, 0x88, 0x19, |
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0x62, 0xF3, 0x81, 0x10, 0x65, 0xF4, 0x86, 0x17, |
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0x48, 0xD9, 0xAB, 0x3A, 0x4F, 0xDE, 0xAC, 0x3D, |
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0x46, 0xD7, 0xA5, 0x34, 0x41, 0xD0, 0xA2, 0x33, |
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0x54, 0xC5, 0xB7, 0x26, 0x53, 0xC2, 0xB0, 0x21, |
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0x5A, 0xCB, 0xB9, 0x28, 0x5D, 0xCC, 0xBE, 0x2F, |
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0xE0, 0x71, 0x03, 0x92, 0xE7, 0x76, 0x04, 0x95, |
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0xEE, 0x7F, 0x0D, 0x9C, 0xE9, 0x78, 0x0A, 0x9B, |
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0xFC, 0x6D, 0x1F, 0x8E, 0xFB, 0x6A, 0x18, 0x89, |
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0xF2, 0x63, 0x11, 0x80, 0xF5, 0x64, 0x16, 0x87, |
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0xD8, 0x49, 0x3B, 0xAA, 0xDF, 0x4E, 0x3C, 0xAD, |
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0xD6, 0x47, 0x35, 0xA4, 0xD1, 0x40, 0x32, 0xA3, |
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0xC4, 0x55, 0x27, 0xB6, 0xC3, 0x52, 0x20, 0xB1, |
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0xCA, 0x5B, 0x29, 0xB8, 0xCD, 0x5C, 0x2E, 0xBF, |
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0x90, 0x01, 0x73, 0xE2, 0x97, 0x06, 0x74, 0xE5, |
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0x9E, 0x0F, 0x7D, 0xEC, 0x99, 0x08, 0x7A, 0xEB, |
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0x8C, 0x1D, 0x6F, 0xFE, 0x8B, 0x1A, 0x68, 0xF9, |
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0x82, 0x13, 0x61, 0xF0, 0x85, 0x14, 0x66, 0xF7, |
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0xA8, 0x39, 0x4B, 0xDA, 0xAF, 0x3E, 0x4C, 0xDD, |
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0xA6, 0x37, 0x45, 0xD4, 0xA1, 0x30, 0x42, 0xD3, |
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0xB4, 0x25, 0x57, 0xC6, 0xB3, 0x22, 0x50, 0xC1, |
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0xBA, 0x2B, 0x59, 0xC8, 0xBD, 0x2C, 0x5E, 0xCF |
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}; |
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|
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#define INIT_FCS 0xFF |
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#define GOOD_FCS 0xCF |
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static int gsmld_output(struct gsm_mux *gsm, u8 *data, int len); |
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|
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/** |
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* gsm_fcs_add - update FCS |
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* @fcs: Current FCS |
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* @c: Next data |
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* |
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* Update the FCS to include c. Uses the algorithm in the specification |
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* notes. |
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*/ |
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static inline u8 gsm_fcs_add(u8 fcs, u8 c) |
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{ |
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return gsm_fcs8[fcs ^ c]; |
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} |
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|
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/** |
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* gsm_fcs_add_block - update FCS for a block |
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* @fcs: Current FCS |
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* @c: buffer of data |
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* @len: length of buffer |
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* |
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* Update the FCS to include c. Uses the algorithm in the specification |
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* notes. |
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*/ |
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|
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static inline u8 gsm_fcs_add_block(u8 fcs, u8 *c, int len) |
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{ |
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while (len--) |
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fcs = gsm_fcs8[fcs ^ *c++]; |
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return fcs; |
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} |
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|
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/** |
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* gsm_read_ea - read a byte into an EA |
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* @val: variable holding value |
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* @c: byte going into the EA |
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* |
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* Processes one byte of an EA. Updates the passed variable |
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* and returns 1 if the EA is now completely read |
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*/ |
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|
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static int gsm_read_ea(unsigned int *val, u8 c) |
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{ |
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/* Add the next 7 bits into the value */ |
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*val <<= 7; |
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*val |= c >> 1; |
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/* Was this the last byte of the EA 1 = yes*/ |
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return c & EA; |
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} |
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|
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/** |
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* gsm_encode_modem - encode modem data bits |
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* @dlci: DLCI to encode from |
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* |
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* Returns the correct GSM encoded modem status bits (6 bit field) for |
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* the current status of the DLCI and attached tty object |
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*/ |
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|
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static u8 gsm_encode_modem(const struct gsm_dlci *dlci) |
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{ |
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u8 modembits = 0; |
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/* FC is true flow control not modem bits */ |
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if (dlci->throttled) |
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modembits |= MDM_FC; |
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if (dlci->modem_tx & TIOCM_DTR) |
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modembits |= MDM_RTC; |
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if (dlci->modem_tx & TIOCM_RTS) |
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modembits |= MDM_RTR; |
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if (dlci->modem_tx & TIOCM_RI) |
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modembits |= MDM_IC; |
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if (dlci->modem_tx & TIOCM_CD) |
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modembits |= MDM_DV; |
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return modembits; |
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} |
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|
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/** |
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* gsm_print_packet - display a frame for debug |
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* @hdr: header to print before decode |
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* @addr: address EA from the frame |
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* @cr: C/R bit from the frame |
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* @control: control including PF bit |
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* @data: following data bytes |
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* @dlen: length of data |
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* |
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* Displays a packet in human readable format for debugging purposes. The |
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* style is based on amateur radio LAP-B dump display. |
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*/ |
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|
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static void gsm_print_packet(const char *hdr, int addr, int cr, |
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u8 control, const u8 *data, int dlen) |
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{ |
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if (!(debug & 1)) |
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return; |
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|
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pr_info("%s %d) %c: ", hdr, addr, "RC"[cr]); |
|
|
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switch (control & ~PF) { |
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case SABM: |
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pr_cont("SABM"); |
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break; |
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case UA: |
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pr_cont("UA"); |
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break; |
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case DISC: |
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pr_cont("DISC"); |
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break; |
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case DM: |
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pr_cont("DM"); |
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break; |
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case UI: |
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pr_cont("UI"); |
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break; |
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case UIH: |
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pr_cont("UIH"); |
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break; |
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default: |
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if (!(control & 0x01)) { |
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pr_cont("I N(S)%d N(R)%d", |
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(control & 0x0E) >> 1, (control & 0xE0) >> 5); |
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} else switch (control & 0x0F) { |
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case RR: |
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pr_cont("RR(%d)", (control & 0xE0) >> 5); |
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break; |
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case RNR: |
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pr_cont("RNR(%d)", (control & 0xE0) >> 5); |
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break; |
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case REJ: |
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pr_cont("REJ(%d)", (control & 0xE0) >> 5); |
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break; |
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default: |
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pr_cont("[%02X]", control); |
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} |
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} |
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|
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if (control & PF) |
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pr_cont("(P)"); |
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else |
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pr_cont("(F)"); |
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|
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print_hex_dump_bytes("", DUMP_PREFIX_NONE, data, dlen); |
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} |
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|
|
|
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/* |
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* Link level transmission side |
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*/ |
|
|
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/** |
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* gsm_stuff_frame - bytestuff a packet |
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* @input: input buffer |
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* @output: output buffer |
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* @len: length of input |
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* |
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* Expand a buffer by bytestuffing it. The worst case size change |
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* is doubling and the caller is responsible for handing out |
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* suitable sized buffers. |
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*/ |
|
|
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static int gsm_stuff_frame(const u8 *input, u8 *output, int len) |
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{ |
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int olen = 0; |
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while (len--) { |
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if (*input == GSM1_SOF || *input == GSM1_ESCAPE |
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|| *input == XON || *input == XOFF) { |
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*output++ = GSM1_ESCAPE; |
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*output++ = *input++ ^ GSM1_ESCAPE_BITS; |
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olen++; |
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} else |
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*output++ = *input++; |
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olen++; |
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} |
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return olen; |
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} |
|
|
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/** |
|
* gsm_send - send a control frame |
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* @gsm: our GSM mux |
|
* @addr: address for control frame |
|
* @cr: command/response bit |
|
* @control: control byte including PF bit |
|
* |
|
* Format up and transmit a control frame. These do not go via the |
|
* queueing logic as they should be transmitted ahead of data when |
|
* they are needed. |
|
* |
|
* FIXME: Lock versus data TX path |
|
*/ |
|
|
|
static void gsm_send(struct gsm_mux *gsm, int addr, int cr, int control) |
|
{ |
|
int len; |
|
u8 cbuf[10]; |
|
u8 ibuf[3]; |
|
|
|
switch (gsm->encoding) { |
|
case 0: |
|
cbuf[0] = GSM0_SOF; |
|
cbuf[1] = (addr << 2) | (cr << 1) | EA; |
|
cbuf[2] = control; |
|
cbuf[3] = EA; /* Length of data = 0 */ |
|
cbuf[4] = 0xFF - gsm_fcs_add_block(INIT_FCS, cbuf + 1, 3); |
|
cbuf[5] = GSM0_SOF; |
|
len = 6; |
|
break; |
|
case 1: |
|
case 2: |
|
/* Control frame + packing (but not frame stuffing) in mode 1 */ |
|
ibuf[0] = (addr << 2) | (cr << 1) | EA; |
|
ibuf[1] = control; |
|
ibuf[2] = 0xFF - gsm_fcs_add_block(INIT_FCS, ibuf, 2); |
|
/* Stuffing may double the size worst case */ |
|
len = gsm_stuff_frame(ibuf, cbuf + 1, 3); |
|
/* Now add the SOF markers */ |
|
cbuf[0] = GSM1_SOF; |
|
cbuf[len + 1] = GSM1_SOF; |
|
/* FIXME: we can omit the lead one in many cases */ |
|
len += 2; |
|
break; |
|
default: |
|
WARN_ON(1); |
|
return; |
|
} |
|
gsmld_output(gsm, cbuf, len); |
|
gsm_print_packet("-->", addr, cr, control, NULL, 0); |
|
} |
|
|
|
/** |
|
* gsm_response - send a control response |
|
* @gsm: our GSM mux |
|
* @addr: address for control frame |
|
* @control: control byte including PF bit |
|
* |
|
* Format up and transmit a link level response frame. |
|
*/ |
|
|
|
static inline void gsm_response(struct gsm_mux *gsm, int addr, int control) |
|
{ |
|
gsm_send(gsm, addr, 0, control); |
|
} |
|
|
|
/** |
|
* gsm_command - send a control command |
|
* @gsm: our GSM mux |
|
* @addr: address for control frame |
|
* @control: control byte including PF bit |
|
* |
|
* Format up and transmit a link level command frame. |
|
*/ |
|
|
|
static inline void gsm_command(struct gsm_mux *gsm, int addr, int control) |
|
{ |
|
gsm_send(gsm, addr, 1, control); |
|
} |
|
|
|
/* Data transmission */ |
|
|
|
#define HDR_LEN 6 /* ADDR CTRL [LEN.2] DATA FCS */ |
|
|
|
/** |
|
* gsm_data_alloc - allocate data frame |
|
* @gsm: GSM mux |
|
* @addr: DLCI address |
|
* @len: length excluding header and FCS |
|
* @ctrl: control byte |
|
* |
|
* Allocate a new data buffer for sending frames with data. Space is left |
|
* at the front for header bytes but that is treated as an implementation |
|
* detail and not for the high level code to use |
|
*/ |
|
|
|
static struct gsm_msg *gsm_data_alloc(struct gsm_mux *gsm, u8 addr, int len, |
|
u8 ctrl) |
|
{ |
|
struct gsm_msg *m = kmalloc(sizeof(struct gsm_msg) + len + HDR_LEN, |
|
GFP_ATOMIC); |
|
if (m == NULL) |
|
return NULL; |
|
m->data = m->buffer + HDR_LEN - 1; /* Allow for FCS */ |
|
m->len = len; |
|
m->addr = addr; |
|
m->ctrl = ctrl; |
|
INIT_LIST_HEAD(&m->list); |
|
return m; |
|
} |
|
|
|
/** |
|
* gsm_data_kick - poke the queue |
|
* @gsm: GSM Mux |
|
* @dlci: DLCI sending the data |
|
* |
|
* The tty device has called us to indicate that room has appeared in |
|
* the transmit queue. Ram more data into the pipe if we have any |
|
* If we have been flow-stopped by a CMD_FCOFF, then we can only |
|
* send messages on DLCI0 until CMD_FCON |
|
* |
|
* FIXME: lock against link layer control transmissions |
|
*/ |
|
|
|
static void gsm_data_kick(struct gsm_mux *gsm, struct gsm_dlci *dlci) |
|
{ |
|
struct gsm_msg *msg, *nmsg; |
|
int len; |
|
|
|
list_for_each_entry_safe(msg, nmsg, &gsm->tx_list, list) { |
|
if (gsm->constipated && msg->addr) |
|
continue; |
|
if (gsm->encoding != 0) { |
|
gsm->txframe[0] = GSM1_SOF; |
|
len = gsm_stuff_frame(msg->data, |
|
gsm->txframe + 1, msg->len); |
|
gsm->txframe[len + 1] = GSM1_SOF; |
|
len += 2; |
|
} else { |
|
gsm->txframe[0] = GSM0_SOF; |
|
memcpy(gsm->txframe + 1 , msg->data, msg->len); |
|
gsm->txframe[msg->len + 1] = GSM0_SOF; |
|
len = msg->len + 2; |
|
} |
|
|
|
if (debug & 4) |
|
print_hex_dump_bytes("gsm_data_kick: ", |
|
DUMP_PREFIX_OFFSET, |
|
gsm->txframe, len); |
|
if (gsmld_output(gsm, gsm->txframe, len) < 0) |
|
break; |
|
/* FIXME: Can eliminate one SOF in many more cases */ |
|
gsm->tx_bytes -= msg->len; |
|
|
|
list_del(&msg->list); |
|
kfree(msg); |
|
|
|
if (dlci) { |
|
tty_port_tty_wakeup(&dlci->port); |
|
} else { |
|
int i = 0; |
|
|
|
for (i = 0; i < NUM_DLCI; i++) |
|
if (gsm->dlci[i]) |
|
tty_port_tty_wakeup(&gsm->dlci[i]->port); |
|
} |
|
} |
|
} |
|
|
|
/** |
|
* __gsm_data_queue - queue a UI or UIH frame |
|
* @dlci: DLCI sending the data |
|
* @msg: message queued |
|
* |
|
* Add data to the transmit queue and try and get stuff moving |
|
* out of the mux tty if not already doing so. The Caller must hold |
|
* the gsm tx lock. |
|
*/ |
|
|
|
static void __gsm_data_queue(struct gsm_dlci *dlci, struct gsm_msg *msg) |
|
{ |
|
struct gsm_mux *gsm = dlci->gsm; |
|
u8 *dp = msg->data; |
|
u8 *fcs = dp + msg->len; |
|
|
|
/* Fill in the header */ |
|
if (gsm->encoding == 0) { |
|
if (msg->len < 128) |
|
*--dp = (msg->len << 1) | EA; |
|
else { |
|
*--dp = (msg->len >> 7); /* bits 7 - 15 */ |
|
*--dp = (msg->len & 127) << 1; /* bits 0 - 6 */ |
|
} |
|
} |
|
|
|
*--dp = msg->ctrl; |
|
if (gsm->initiator) |
|
*--dp = (msg->addr << 2) | 2 | EA; |
|
else |
|
*--dp = (msg->addr << 2) | EA; |
|
*fcs = gsm_fcs_add_block(INIT_FCS, dp , msg->data - dp); |
|
/* Ugly protocol layering violation */ |
|
if (msg->ctrl == UI || msg->ctrl == (UI|PF)) |
|
*fcs = gsm_fcs_add_block(*fcs, msg->data, msg->len); |
|
*fcs = 0xFF - *fcs; |
|
|
|
gsm_print_packet("Q> ", msg->addr, gsm->initiator, msg->ctrl, |
|
msg->data, msg->len); |
|
|
|
/* Move the header back and adjust the length, also allow for the FCS |
|
now tacked on the end */ |
|
msg->len += (msg->data - dp) + 1; |
|
msg->data = dp; |
|
|
|
/* Add to the actual output queue */ |
|
list_add_tail(&msg->list, &gsm->tx_list); |
|
gsm->tx_bytes += msg->len; |
|
gsm_data_kick(gsm, dlci); |
|
} |
|
|
|
/** |
|
* gsm_data_queue - queue a UI or UIH frame |
|
* @dlci: DLCI sending the data |
|
* @msg: message queued |
|
* |
|
* Add data to the transmit queue and try and get stuff moving |
|
* out of the mux tty if not already doing so. Take the |
|
* the gsm tx lock and dlci lock. |
|
*/ |
|
|
|
static void gsm_data_queue(struct gsm_dlci *dlci, struct gsm_msg *msg) |
|
{ |
|
unsigned long flags; |
|
spin_lock_irqsave(&dlci->gsm->tx_lock, flags); |
|
__gsm_data_queue(dlci, msg); |
|
spin_unlock_irqrestore(&dlci->gsm->tx_lock, flags); |
|
} |
|
|
|
/** |
|
* gsm_dlci_data_output - try and push data out of a DLCI |
|
* @gsm: mux |
|
* @dlci: the DLCI to pull data from |
|
* |
|
* Pull data from a DLCI and send it into the transmit queue if there |
|
* is data. Keep to the MRU of the mux. This path handles the usual tty |
|
* interface which is a byte stream with optional modem data. |
|
* |
|
* Caller must hold the tx_lock of the mux. |
|
*/ |
|
|
|
static int gsm_dlci_data_output(struct gsm_mux *gsm, struct gsm_dlci *dlci) |
|
{ |
|
struct gsm_msg *msg; |
|
u8 *dp; |
|
int len, total_size, size; |
|
int h = dlci->adaption - 1; |
|
|
|
total_size = 0; |
|
while (1) { |
|
len = kfifo_len(&dlci->fifo); |
|
if (len == 0) |
|
return total_size; |
|
|
|
/* MTU/MRU count only the data bits */ |
|
if (len > gsm->mtu) |
|
len = gsm->mtu; |
|
|
|
size = len + h; |
|
|
|
msg = gsm_data_alloc(gsm, dlci->addr, size, gsm->ftype); |
|
/* FIXME: need a timer or something to kick this so it can't |
|
get stuck with no work outstanding and no buffer free */ |
|
if (msg == NULL) |
|
return -ENOMEM; |
|
dp = msg->data; |
|
switch (dlci->adaption) { |
|
case 1: /* Unstructured */ |
|
break; |
|
case 2: /* Unstructed with modem bits. |
|
Always one byte as we never send inline break data */ |
|
*dp++ = gsm_encode_modem(dlci); |
|
break; |
|
} |
|
WARN_ON(kfifo_out_locked(&dlci->fifo, dp , len, &dlci->lock) != len); |
|
__gsm_data_queue(dlci, msg); |
|
total_size += size; |
|
} |
|
/* Bytes of data we used up */ |
|
return total_size; |
|
} |
|
|
|
/** |
|
* gsm_dlci_data_output_framed - try and push data out of a DLCI |
|
* @gsm: mux |
|
* @dlci: the DLCI to pull data from |
|
* |
|
* Pull data from a DLCI and send it into the transmit queue if there |
|
* is data. Keep to the MRU of the mux. This path handles framed data |
|
* queued as skbuffs to the DLCI. |
|
* |
|
* Caller must hold the tx_lock of the mux. |
|
*/ |
|
|
|
static int gsm_dlci_data_output_framed(struct gsm_mux *gsm, |
|
struct gsm_dlci *dlci) |
|
{ |
|
struct gsm_msg *msg; |
|
u8 *dp; |
|
int len, size; |
|
int last = 0, first = 0; |
|
int overhead = 0; |
|
|
|
/* One byte per frame is used for B/F flags */ |
|
if (dlci->adaption == 4) |
|
overhead = 1; |
|
|
|
/* dlci->skb is locked by tx_lock */ |
|
if (dlci->skb == NULL) { |
|
dlci->skb = skb_dequeue_tail(&dlci->skb_list); |
|
if (dlci->skb == NULL) |
|
return 0; |
|
first = 1; |
|
} |
|
len = dlci->skb->len + overhead; |
|
|
|
/* MTU/MRU count only the data bits */ |
|
if (len > gsm->mtu) { |
|
if (dlci->adaption == 3) { |
|
/* Over long frame, bin it */ |
|
dev_kfree_skb_any(dlci->skb); |
|
dlci->skb = NULL; |
|
return 0; |
|
} |
|
len = gsm->mtu; |
|
} else |
|
last = 1; |
|
|
|
size = len + overhead; |
|
msg = gsm_data_alloc(gsm, dlci->addr, size, gsm->ftype); |
|
|
|
/* FIXME: need a timer or something to kick this so it can't |
|
get stuck with no work outstanding and no buffer free */ |
|
if (msg == NULL) { |
|
skb_queue_tail(&dlci->skb_list, dlci->skb); |
|
dlci->skb = NULL; |
|
return -ENOMEM; |
|
} |
|
dp = msg->data; |
|
|
|
if (dlci->adaption == 4) { /* Interruptible framed (Packetised Data) */ |
|
/* Flag byte to carry the start/end info */ |
|
*dp++ = last << 7 | first << 6 | 1; /* EA */ |
|
len--; |
|
} |
|
memcpy(dp, dlci->skb->data, len); |
|
skb_pull(dlci->skb, len); |
|
__gsm_data_queue(dlci, msg); |
|
if (last) { |
|
dev_kfree_skb_any(dlci->skb); |
|
dlci->skb = NULL; |
|
} |
|
return size; |
|
} |
|
|
|
/** |
|
* gsm_dlci_data_sweep - look for data to send |
|
* @gsm: the GSM mux |
|
* |
|
* Sweep the GSM mux channels in priority order looking for ones with |
|
* data to send. We could do with optimising this scan a bit. We aim |
|
* to fill the queue totally or up to TX_THRESH_HI bytes. Once we hit |
|
* TX_THRESH_LO we get called again |
|
* |
|
* FIXME: We should round robin between groups and in theory you can |
|
* renegotiate DLCI priorities with optional stuff. Needs optimising. |
|
*/ |
|
|
|
static void gsm_dlci_data_sweep(struct gsm_mux *gsm) |
|
{ |
|
int len; |
|
/* Priority ordering: We should do priority with RR of the groups */ |
|
int i = 1; |
|
|
|
while (i < NUM_DLCI) { |
|
struct gsm_dlci *dlci; |
|
|
|
if (gsm->tx_bytes > TX_THRESH_HI) |
|
break; |
|
dlci = gsm->dlci[i]; |
|
if (dlci == NULL || dlci->constipated) { |
|
i++; |
|
continue; |
|
} |
|
if (dlci->adaption < 3 && !dlci->net) |
|
len = gsm_dlci_data_output(gsm, dlci); |
|
else |
|
len = gsm_dlci_data_output_framed(gsm, dlci); |
|
if (len < 0) |
|
break; |
|
/* DLCI empty - try the next */ |
|
if (len == 0) |
|
i++; |
|
} |
|
} |
|
|
|
/** |
|
* gsm_dlci_data_kick - transmit if possible |
|
* @dlci: DLCI to kick |
|
* |
|
* Transmit data from this DLCI if the queue is empty. We can't rely on |
|
* a tty wakeup except when we filled the pipe so we need to fire off |
|
* new data ourselves in other cases. |
|
*/ |
|
|
|
static void gsm_dlci_data_kick(struct gsm_dlci *dlci) |
|
{ |
|
unsigned long flags; |
|
int sweep; |
|
|
|
if (dlci->constipated) |
|
return; |
|
|
|
spin_lock_irqsave(&dlci->gsm->tx_lock, flags); |
|
/* If we have nothing running then we need to fire up */ |
|
sweep = (dlci->gsm->tx_bytes < TX_THRESH_LO); |
|
if (dlci->gsm->tx_bytes == 0) { |
|
if (dlci->net) |
|
gsm_dlci_data_output_framed(dlci->gsm, dlci); |
|
else |
|
gsm_dlci_data_output(dlci->gsm, dlci); |
|
} |
|
if (sweep) |
|
gsm_dlci_data_sweep(dlci->gsm); |
|
spin_unlock_irqrestore(&dlci->gsm->tx_lock, flags); |
|
} |
|
|
|
/* |
|
* Control message processing |
|
*/ |
|
|
|
|
|
/** |
|
* gsm_control_reply - send a response frame to a control |
|
* @gsm: gsm channel |
|
* @cmd: the command to use |
|
* @data: data to follow encoded info |
|
* @dlen: length of data |
|
* |
|
* Encode up and queue a UI/UIH frame containing our response. |
|
*/ |
|
|
|
static void gsm_control_reply(struct gsm_mux *gsm, int cmd, const u8 *data, |
|
int dlen) |
|
{ |
|
struct gsm_msg *msg; |
|
msg = gsm_data_alloc(gsm, 0, dlen + 2, gsm->ftype); |
|
if (msg == NULL) |
|
return; |
|
msg->data[0] = (cmd & 0xFE) << 1 | EA; /* Clear C/R */ |
|
msg->data[1] = (dlen << 1) | EA; |
|
memcpy(msg->data + 2, data, dlen); |
|
gsm_data_queue(gsm->dlci[0], msg); |
|
} |
|
|
|
/** |
|
* gsm_process_modem - process received modem status |
|
* @tty: virtual tty bound to the DLCI |
|
* @dlci: DLCI to affect |
|
* @modem: modem bits (full EA) |
|
* @clen: command length |
|
* |
|
* Used when a modem control message or line state inline in adaption |
|
* layer 2 is processed. Sort out the local modem state and throttles |
|
*/ |
|
|
|
static void gsm_process_modem(struct tty_struct *tty, struct gsm_dlci *dlci, |
|
u32 modem, int clen) |
|
{ |
|
int mlines = 0; |
|
u8 brk = 0; |
|
int fc; |
|
|
|
/* The modem status command can either contain one octet (v.24 signals) |
|
or two octets (v.24 signals + break signals). The length field will |
|
either be 2 or 3 respectively. This is specified in section |
|
5.4.6.3.7 of the 27.010 mux spec. */ |
|
|
|
if (clen == 2) |
|
modem = modem & 0x7f; |
|
else { |
|
brk = modem & 0x7f; |
|
modem = (modem >> 7) & 0x7f; |
|
} |
|
|
|
/* Flow control/ready to communicate */ |
|
fc = (modem & MDM_FC) || !(modem & MDM_RTR); |
|
if (fc && !dlci->constipated) { |
|
/* Need to throttle our output on this device */ |
|
dlci->constipated = true; |
|
} else if (!fc && dlci->constipated) { |
|
dlci->constipated = false; |
|
gsm_dlci_data_kick(dlci); |
|
} |
|
|
|
/* Map modem bits */ |
|
if (modem & MDM_RTC) |
|
mlines |= TIOCM_DSR | TIOCM_DTR; |
|
if (modem & MDM_RTR) |
|
mlines |= TIOCM_RTS | TIOCM_CTS; |
|
if (modem & MDM_IC) |
|
mlines |= TIOCM_RI; |
|
if (modem & MDM_DV) |
|
mlines |= TIOCM_CD; |
|
|
|
/* Carrier drop -> hangup */ |
|
if (tty) { |
|
if ((mlines & TIOCM_CD) == 0 && (dlci->modem_rx & TIOCM_CD)) |
|
if (!C_CLOCAL(tty)) |
|
tty_hangup(tty); |
|
} |
|
if (brk & 0x01) |
|
tty_insert_flip_char(&dlci->port, 0, TTY_BREAK); |
|
dlci->modem_rx = mlines; |
|
} |
|
|
|
/** |
|
* gsm_control_modem - modem status received |
|
* @gsm: GSM channel |
|
* @data: data following command |
|
* @clen: command length |
|
* |
|
* We have received a modem status control message. This is used by |
|
* the GSM mux protocol to pass virtual modem line status and optionally |
|
* to indicate break signals. Unpack it, convert to Linux representation |
|
* and if need be stuff a break message down the tty. |
|
*/ |
|
|
|
static void gsm_control_modem(struct gsm_mux *gsm, const u8 *data, int clen) |
|
{ |
|
unsigned int addr = 0; |
|
unsigned int modem = 0; |
|
unsigned int brk = 0; |
|
struct gsm_dlci *dlci; |
|
int len = clen; |
|
const u8 *dp = data; |
|
struct tty_struct *tty; |
|
|
|
while (gsm_read_ea(&addr, *dp++) == 0) { |
|
len--; |
|
if (len == 0) |
|
return; |
|
} |
|
/* Must be at least one byte following the EA */ |
|
len--; |
|
if (len <= 0) |
|
return; |
|
|
|
addr >>= 1; |
|
/* Closed port, or invalid ? */ |
|
if (addr == 0 || addr >= NUM_DLCI || gsm->dlci[addr] == NULL) |
|
return; |
|
dlci = gsm->dlci[addr]; |
|
|
|
while (gsm_read_ea(&modem, *dp++) == 0) { |
|
len--; |
|
if (len == 0) |
|
return; |
|
} |
|
len--; |
|
if (len > 0) { |
|
while (gsm_read_ea(&brk, *dp++) == 0) { |
|
len--; |
|
if (len == 0) |
|
return; |
|
} |
|
modem <<= 7; |
|
modem |= (brk & 0x7f); |
|
} |
|
tty = tty_port_tty_get(&dlci->port); |
|
gsm_process_modem(tty, dlci, modem, clen); |
|
if (tty) { |
|
tty_wakeup(tty); |
|
tty_kref_put(tty); |
|
} |
|
gsm_control_reply(gsm, CMD_MSC, data, clen); |
|
} |
|
|
|
/** |
|
* gsm_control_rls - remote line status |
|
* @gsm: GSM channel |
|
* @data: data bytes |
|
* @clen: data length |
|
* |
|
* The modem sends us a two byte message on the control channel whenever |
|
* it wishes to send us an error state from the virtual link. Stuff |
|
* this into the uplink tty if present |
|
*/ |
|
|
|
static void gsm_control_rls(struct gsm_mux *gsm, const u8 *data, int clen) |
|
{ |
|
struct tty_port *port; |
|
unsigned int addr = 0; |
|
u8 bits; |
|
int len = clen; |
|
const u8 *dp = data; |
|
|
|
while (gsm_read_ea(&addr, *dp++) == 0) { |
|
len--; |
|
if (len == 0) |
|
return; |
|
} |
|
/* Must be at least one byte following ea */ |
|
len--; |
|
if (len <= 0) |
|
return; |
|
addr >>= 1; |
|
/* Closed port, or invalid ? */ |
|
if (addr == 0 || addr >= NUM_DLCI || gsm->dlci[addr] == NULL) |
|
return; |
|
/* No error ? */ |
|
bits = *dp; |
|
if ((bits & 1) == 0) |
|
return; |
|
|
|
port = &gsm->dlci[addr]->port; |
|
|
|
if (bits & 2) |
|
tty_insert_flip_char(port, 0, TTY_OVERRUN); |
|
if (bits & 4) |
|
tty_insert_flip_char(port, 0, TTY_PARITY); |
|
if (bits & 8) |
|
tty_insert_flip_char(port, 0, TTY_FRAME); |
|
|
|
tty_flip_buffer_push(port); |
|
|
|
gsm_control_reply(gsm, CMD_RLS, data, clen); |
|
} |
|
|
|
static void gsm_dlci_begin_close(struct gsm_dlci *dlci); |
|
|
|
/** |
|
* gsm_control_message - DLCI 0 control processing |
|
* @gsm: our GSM mux |
|
* @command: the command EA |
|
* @data: data beyond the command/length EAs |
|
* @clen: length |
|
* |
|
* Input processor for control messages from the other end of the link. |
|
* Processes the incoming request and queues a response frame or an |
|
* NSC response if not supported |
|
*/ |
|
|
|
static void gsm_control_message(struct gsm_mux *gsm, unsigned int command, |
|
const u8 *data, int clen) |
|
{ |
|
u8 buf[1]; |
|
unsigned long flags; |
|
|
|
switch (command) { |
|
case CMD_CLD: { |
|
struct gsm_dlci *dlci = gsm->dlci[0]; |
|
/* Modem wishes to close down */ |
|
if (dlci) { |
|
dlci->dead = true; |
|
gsm->dead = true; |
|
gsm_dlci_begin_close(dlci); |
|
} |
|
} |
|
break; |
|
case CMD_TEST: |
|
/* Modem wishes to test, reply with the data */ |
|
gsm_control_reply(gsm, CMD_TEST, data, clen); |
|
break; |
|
case CMD_FCON: |
|
/* Modem can accept data again */ |
|
gsm->constipated = false; |
|
gsm_control_reply(gsm, CMD_FCON, NULL, 0); |
|
/* Kick the link in case it is idling */ |
|
spin_lock_irqsave(&gsm->tx_lock, flags); |
|
gsm_data_kick(gsm, NULL); |
|
spin_unlock_irqrestore(&gsm->tx_lock, flags); |
|
break; |
|
case CMD_FCOFF: |
|
/* Modem wants us to STFU */ |
|
gsm->constipated = true; |
|
gsm_control_reply(gsm, CMD_FCOFF, NULL, 0); |
|
break; |
|
case CMD_MSC: |
|
/* Out of band modem line change indicator for a DLCI */ |
|
gsm_control_modem(gsm, data, clen); |
|
break; |
|
case CMD_RLS: |
|
/* Out of band error reception for a DLCI */ |
|
gsm_control_rls(gsm, data, clen); |
|
break; |
|
case CMD_PSC: |
|
/* Modem wishes to enter power saving state */ |
|
gsm_control_reply(gsm, CMD_PSC, NULL, 0); |
|
break; |
|
/* Optional unsupported commands */ |
|
case CMD_PN: /* Parameter negotiation */ |
|
case CMD_RPN: /* Remote port negotiation */ |
|
case CMD_SNC: /* Service negotiation command */ |
|
default: |
|
/* Reply to bad commands with an NSC */ |
|
buf[0] = command; |
|
gsm_control_reply(gsm, CMD_NSC, buf, 1); |
|
break; |
|
} |
|
} |
|
|
|
/** |
|
* gsm_control_response - process a response to our control |
|
* @gsm: our GSM mux |
|
* @command: the command (response) EA |
|
* @data: data beyond the command/length EA |
|
* @clen: length |
|
* |
|
* Process a response to an outstanding command. We only allow a single |
|
* control message in flight so this is fairly easy. All the clean up |
|
* is done by the caller, we just update the fields, flag it as done |
|
* and return |
|
*/ |
|
|
|
static void gsm_control_response(struct gsm_mux *gsm, unsigned int command, |
|
const u8 *data, int clen) |
|
{ |
|
struct gsm_control *ctrl; |
|
unsigned long flags; |
|
|
|
spin_lock_irqsave(&gsm->control_lock, flags); |
|
|
|
ctrl = gsm->pending_cmd; |
|
/* Does the reply match our command */ |
|
command |= 1; |
|
if (ctrl != NULL && (command == ctrl->cmd || command == CMD_NSC)) { |
|
/* Our command was replied to, kill the retry timer */ |
|
del_timer(&gsm->t2_timer); |
|
gsm->pending_cmd = NULL; |
|
/* Rejected by the other end */ |
|
if (command == CMD_NSC) |
|
ctrl->error = -EOPNOTSUPP; |
|
ctrl->done = 1; |
|
wake_up(&gsm->event); |
|
} |
|
spin_unlock_irqrestore(&gsm->control_lock, flags); |
|
} |
|
|
|
/** |
|
* gsm_control_transmit - send control packet |
|
* @gsm: gsm mux |
|
* @ctrl: frame to send |
|
* |
|
* Send out a pending control command (called under control lock) |
|
*/ |
|
|
|
static void gsm_control_transmit(struct gsm_mux *gsm, struct gsm_control *ctrl) |
|
{ |
|
struct gsm_msg *msg = gsm_data_alloc(gsm, 0, ctrl->len + 1, gsm->ftype); |
|
if (msg == NULL) |
|
return; |
|
msg->data[0] = (ctrl->cmd << 1) | 2 | EA; /* command */ |
|
memcpy(msg->data + 1, ctrl->data, ctrl->len); |
|
gsm_data_queue(gsm->dlci[0], msg); |
|
} |
|
|
|
/** |
|
* gsm_control_retransmit - retransmit a control frame |
|
* @t: timer contained in our gsm object |
|
* |
|
* Called off the T2 timer expiry in order to retransmit control frames |
|
* that have been lost in the system somewhere. The control_lock protects |
|
* us from colliding with another sender or a receive completion event. |
|
* In that situation the timer may still occur in a small window but |
|
* gsm->pending_cmd will be NULL and we just let the timer expire. |
|
*/ |
|
|
|
static void gsm_control_retransmit(struct timer_list *t) |
|
{ |
|
struct gsm_mux *gsm = from_timer(gsm, t, t2_timer); |
|
struct gsm_control *ctrl; |
|
unsigned long flags; |
|
spin_lock_irqsave(&gsm->control_lock, flags); |
|
ctrl = gsm->pending_cmd; |
|
if (ctrl) { |
|
gsm->cretries--; |
|
if (gsm->cretries == 0) { |
|
gsm->pending_cmd = NULL; |
|
ctrl->error = -ETIMEDOUT; |
|
ctrl->done = 1; |
|
spin_unlock_irqrestore(&gsm->control_lock, flags); |
|
wake_up(&gsm->event); |
|
return; |
|
} |
|
gsm_control_transmit(gsm, ctrl); |
|
mod_timer(&gsm->t2_timer, jiffies + gsm->t2 * HZ / 100); |
|
} |
|
spin_unlock_irqrestore(&gsm->control_lock, flags); |
|
} |
|
|
|
/** |
|
* gsm_control_send - send a control frame on DLCI 0 |
|
* @gsm: the GSM channel |
|
* @command: command to send including CR bit |
|
* @data: bytes of data (must be kmalloced) |
|
* @clen: length of the block to send |
|
* |
|
* Queue and dispatch a control command. Only one command can be |
|
* active at a time. In theory more can be outstanding but the matching |
|
* gets really complicated so for now stick to one outstanding. |
|
*/ |
|
|
|
static struct gsm_control *gsm_control_send(struct gsm_mux *gsm, |
|
unsigned int command, u8 *data, int clen) |
|
{ |
|
struct gsm_control *ctrl = kzalloc(sizeof(struct gsm_control), |
|
GFP_KERNEL); |
|
unsigned long flags; |
|
if (ctrl == NULL) |
|
return NULL; |
|
retry: |
|
wait_event(gsm->event, gsm->pending_cmd == NULL); |
|
spin_lock_irqsave(&gsm->control_lock, flags); |
|
if (gsm->pending_cmd != NULL) { |
|
spin_unlock_irqrestore(&gsm->control_lock, flags); |
|
goto retry; |
|
} |
|
ctrl->cmd = command; |
|
ctrl->data = data; |
|
ctrl->len = clen; |
|
gsm->pending_cmd = ctrl; |
|
|
|
/* If DLCI0 is in ADM mode skip retries, it won't respond */ |
|
if (gsm->dlci[0]->mode == DLCI_MODE_ADM) |
|
gsm->cretries = 1; |
|
else |
|
gsm->cretries = gsm->n2; |
|
|
|
mod_timer(&gsm->t2_timer, jiffies + gsm->t2 * HZ / 100); |
|
gsm_control_transmit(gsm, ctrl); |
|
spin_unlock_irqrestore(&gsm->control_lock, flags); |
|
return ctrl; |
|
} |
|
|
|
/** |
|
* gsm_control_wait - wait for a control to finish |
|
* @gsm: GSM mux |
|
* @control: control we are waiting on |
|
* |
|
* Waits for the control to complete or time out. Frees any used |
|
* resources and returns 0 for success, or an error if the remote |
|
* rejected or ignored the request. |
|
*/ |
|
|
|
static int gsm_control_wait(struct gsm_mux *gsm, struct gsm_control *control) |
|
{ |
|
int err; |
|
wait_event(gsm->event, control->done == 1); |
|
err = control->error; |
|
kfree(control); |
|
return err; |
|
} |
|
|
|
|
|
/* |
|
* DLCI level handling: Needs krefs |
|
*/ |
|
|
|
/* |
|
* State transitions and timers |
|
*/ |
|
|
|
/** |
|
* gsm_dlci_close - a DLCI has closed |
|
* @dlci: DLCI that closed |
|
* |
|
* Perform processing when moving a DLCI into closed state. If there |
|
* is an attached tty this is hung up |
|
*/ |
|
|
|
static void gsm_dlci_close(struct gsm_dlci *dlci) |
|
{ |
|
del_timer(&dlci->t1); |
|
if (debug & 8) |
|
pr_debug("DLCI %d goes closed.\n", dlci->addr); |
|
dlci->state = DLCI_CLOSED; |
|
if (dlci->addr != 0) { |
|
tty_port_tty_hangup(&dlci->port, false); |
|
kfifo_reset(&dlci->fifo); |
|
} else |
|
dlci->gsm->dead = true; |
|
wake_up(&dlci->gsm->event); |
|
/* A DLCI 0 close is a MUX termination so we need to kick that |
|
back to userspace somehow */ |
|
} |
|
|
|
/** |
|
* gsm_dlci_open - a DLCI has opened |
|
* @dlci: DLCI that opened |
|
* |
|
* Perform processing when moving a DLCI into open state. |
|
*/ |
|
|
|
static void gsm_dlci_open(struct gsm_dlci *dlci) |
|
{ |
|
/* Note that SABM UA .. SABM UA first UA lost can mean that we go |
|
open -> open */ |
|
del_timer(&dlci->t1); |
|
/* This will let a tty open continue */ |
|
dlci->state = DLCI_OPEN; |
|
if (debug & 8) |
|
pr_debug("DLCI %d goes open.\n", dlci->addr); |
|
wake_up(&dlci->gsm->event); |
|
} |
|
|
|
/** |
|
* gsm_dlci_t1 - T1 timer expiry |
|
* @t: timer contained in the DLCI that opened |
|
* |
|
* The T1 timer handles retransmits of control frames (essentially of |
|
* SABM and DISC). We resend the command until the retry count runs out |
|
* in which case an opening port goes back to closed and a closing port |
|
* is simply put into closed state (any further frames from the other |
|
* end will get a DM response) |
|
* |
|
* Some control dlci can stay in ADM mode with other dlci working just |
|
* fine. In that case we can just keep the control dlci open after the |
|
* DLCI_OPENING retries time out. |
|
*/ |
|
|
|
static void gsm_dlci_t1(struct timer_list *t) |
|
{ |
|
struct gsm_dlci *dlci = from_timer(dlci, t, t1); |
|
struct gsm_mux *gsm = dlci->gsm; |
|
|
|
switch (dlci->state) { |
|
case DLCI_OPENING: |
|
dlci->retries--; |
|
if (dlci->retries) { |
|
gsm_command(dlci->gsm, dlci->addr, SABM|PF); |
|
mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100); |
|
} else if (!dlci->addr && gsm->control == (DM | PF)) { |
|
if (debug & 8) |
|
pr_info("DLCI %d opening in ADM mode.\n", |
|
dlci->addr); |
|
dlci->mode = DLCI_MODE_ADM; |
|
gsm_dlci_open(dlci); |
|
} else { |
|
gsm_dlci_close(dlci); |
|
} |
|
|
|
break; |
|
case DLCI_CLOSING: |
|
dlci->retries--; |
|
if (dlci->retries) { |
|
gsm_command(dlci->gsm, dlci->addr, DISC|PF); |
|
mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100); |
|
} else |
|
gsm_dlci_close(dlci); |
|
break; |
|
default: |
|
pr_debug("%s: unhandled state: %d\n", __func__, dlci->state); |
|
break; |
|
} |
|
} |
|
|
|
/** |
|
* gsm_dlci_begin_open - start channel open procedure |
|
* @dlci: DLCI to open |
|
* |
|
* Commence opening a DLCI from the Linux side. We issue SABM messages |
|
* to the modem which should then reply with a UA or ADM, at which point |
|
* we will move into open state. Opening is done asynchronously with retry |
|
* running off timers and the responses. |
|
*/ |
|
|
|
static void gsm_dlci_begin_open(struct gsm_dlci *dlci) |
|
{ |
|
struct gsm_mux *gsm = dlci->gsm; |
|
if (dlci->state == DLCI_OPEN || dlci->state == DLCI_OPENING) |
|
return; |
|
dlci->retries = gsm->n2; |
|
dlci->state = DLCI_OPENING; |
|
gsm_command(dlci->gsm, dlci->addr, SABM|PF); |
|
mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100); |
|
} |
|
|
|
/** |
|
* gsm_dlci_begin_close - start channel open procedure |
|
* @dlci: DLCI to open |
|
* |
|
* Commence closing a DLCI from the Linux side. We issue DISC messages |
|
* to the modem which should then reply with a UA, at which point we |
|
* will move into closed state. Closing is done asynchronously with retry |
|
* off timers. We may also receive a DM reply from the other end which |
|
* indicates the channel was already closed. |
|
*/ |
|
|
|
static void gsm_dlci_begin_close(struct gsm_dlci *dlci) |
|
{ |
|
struct gsm_mux *gsm = dlci->gsm; |
|
if (dlci->state == DLCI_CLOSED || dlci->state == DLCI_CLOSING) |
|
return; |
|
dlci->retries = gsm->n2; |
|
dlci->state = DLCI_CLOSING; |
|
gsm_command(dlci->gsm, dlci->addr, DISC|PF); |
|
mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100); |
|
} |
|
|
|
/** |
|
* gsm_dlci_data - data arrived |
|
* @dlci: channel |
|
* @data: block of bytes received |
|
* @clen: length of received block |
|
* |
|
* A UI or UIH frame has arrived which contains data for a channel |
|
* other than the control channel. If the relevant virtual tty is |
|
* open we shovel the bits down it, if not we drop them. |
|
*/ |
|
|
|
static void gsm_dlci_data(struct gsm_dlci *dlci, const u8 *data, int clen) |
|
{ |
|
/* krefs .. */ |
|
struct tty_port *port = &dlci->port; |
|
struct tty_struct *tty; |
|
unsigned int modem = 0; |
|
int len = clen; |
|
|
|
if (debug & 16) |
|
pr_debug("%d bytes for tty\n", len); |
|
switch (dlci->adaption) { |
|
/* Unsupported types */ |
|
case 4: /* Packetised interruptible data */ |
|
break; |
|
case 3: /* Packetised uininterruptible voice/data */ |
|
break; |
|
case 2: /* Asynchronous serial with line state in each frame */ |
|
while (gsm_read_ea(&modem, *data++) == 0) { |
|
len--; |
|
if (len == 0) |
|
return; |
|
} |
|
tty = tty_port_tty_get(port); |
|
if (tty) { |
|
gsm_process_modem(tty, dlci, modem, clen); |
|
tty_kref_put(tty); |
|
} |
|
fallthrough; |
|
case 1: /* Line state will go via DLCI 0 controls only */ |
|
default: |
|
tty_insert_flip_string(port, data, len); |
|
tty_flip_buffer_push(port); |
|
} |
|
} |
|
|
|
/** |
|
* gsm_dlci_command - data arrived on control channel |
|
* @dlci: channel |
|
* @data: block of bytes received |
|
* @len: length of received block |
|
* |
|
* A UI or UIH frame has arrived which contains data for DLCI 0 the |
|
* control channel. This should contain a command EA followed by |
|
* control data bytes. The command EA contains a command/response bit |
|
* and we divide up the work accordingly. |
|
*/ |
|
|
|
static void gsm_dlci_command(struct gsm_dlci *dlci, const u8 *data, int len) |
|
{ |
|
/* See what command is involved */ |
|
unsigned int command = 0; |
|
while (len-- > 0) { |
|
if (gsm_read_ea(&command, *data++) == 1) { |
|
int clen = *data++; |
|
len--; |
|
/* FIXME: this is properly an EA */ |
|
clen >>= 1; |
|
/* Malformed command ? */ |
|
if (clen > len) |
|
return; |
|
if (command & 1) |
|
gsm_control_message(dlci->gsm, command, |
|
data, clen); |
|
else |
|
gsm_control_response(dlci->gsm, command, |
|
data, clen); |
|
return; |
|
} |
|
} |
|
} |
|
|
|
/* |
|
* Allocate/Free DLCI channels |
|
*/ |
|
|
|
/** |
|
* gsm_dlci_alloc - allocate a DLCI |
|
* @gsm: GSM mux |
|
* @addr: address of the DLCI |
|
* |
|
* Allocate and install a new DLCI object into the GSM mux. |
|
* |
|
* FIXME: review locking races |
|
*/ |
|
|
|
static struct gsm_dlci *gsm_dlci_alloc(struct gsm_mux *gsm, int addr) |
|
{ |
|
struct gsm_dlci *dlci = kzalloc(sizeof(struct gsm_dlci), GFP_ATOMIC); |
|
if (dlci == NULL) |
|
return NULL; |
|
spin_lock_init(&dlci->lock); |
|
mutex_init(&dlci->mutex); |
|
if (kfifo_alloc(&dlci->fifo, 4096, GFP_KERNEL) < 0) { |
|
kfree(dlci); |
|
return NULL; |
|
} |
|
|
|
skb_queue_head_init(&dlci->skb_list); |
|
timer_setup(&dlci->t1, gsm_dlci_t1, 0); |
|
tty_port_init(&dlci->port); |
|
dlci->port.ops = &gsm_port_ops; |
|
dlci->gsm = gsm; |
|
dlci->addr = addr; |
|
dlci->adaption = gsm->adaption; |
|
dlci->state = DLCI_CLOSED; |
|
if (addr) |
|
dlci->data = gsm_dlci_data; |
|
else |
|
dlci->data = gsm_dlci_command; |
|
gsm->dlci[addr] = dlci; |
|
return dlci; |
|
} |
|
|
|
/** |
|
* gsm_dlci_free - free DLCI |
|
* @port: tty port for DLCI to free |
|
* |
|
* Free up a DLCI. |
|
* |
|
* Can sleep. |
|
*/ |
|
static void gsm_dlci_free(struct tty_port *port) |
|
{ |
|
struct gsm_dlci *dlci = container_of(port, struct gsm_dlci, port); |
|
|
|
del_timer_sync(&dlci->t1); |
|
dlci->gsm->dlci[dlci->addr] = NULL; |
|
kfifo_free(&dlci->fifo); |
|
while ((dlci->skb = skb_dequeue(&dlci->skb_list))) |
|
dev_kfree_skb(dlci->skb); |
|
kfree(dlci); |
|
} |
|
|
|
static inline void dlci_get(struct gsm_dlci *dlci) |
|
{ |
|
tty_port_get(&dlci->port); |
|
} |
|
|
|
static inline void dlci_put(struct gsm_dlci *dlci) |
|
{ |
|
tty_port_put(&dlci->port); |
|
} |
|
|
|
static void gsm_destroy_network(struct gsm_dlci *dlci); |
|
|
|
/** |
|
* gsm_dlci_release - release DLCI |
|
* @dlci: DLCI to destroy |
|
* |
|
* Release a DLCI. Actual free is deferred until either |
|
* mux is closed or tty is closed - whichever is last. |
|
* |
|
* Can sleep. |
|
*/ |
|
static void gsm_dlci_release(struct gsm_dlci *dlci) |
|
{ |
|
struct tty_struct *tty = tty_port_tty_get(&dlci->port); |
|
if (tty) { |
|
mutex_lock(&dlci->mutex); |
|
gsm_destroy_network(dlci); |
|
mutex_unlock(&dlci->mutex); |
|
|
|
tty_hangup(tty); |
|
|
|
tty_port_tty_set(&dlci->port, NULL); |
|
tty_kref_put(tty); |
|
} |
|
dlci->state = DLCI_CLOSED; |
|
dlci_put(dlci); |
|
} |
|
|
|
/* |
|
* LAPBish link layer logic |
|
*/ |
|
|
|
/** |
|
* gsm_queue - a GSM frame is ready to process |
|
* @gsm: pointer to our gsm mux |
|
* |
|
* At this point in time a frame has arrived and been demangled from |
|
* the line encoding. All the differences between the encodings have |
|
* been handled below us and the frame is unpacked into the structures. |
|
* The fcs holds the header FCS but any data FCS must be added here. |
|
*/ |
|
|
|
static void gsm_queue(struct gsm_mux *gsm) |
|
{ |
|
struct gsm_dlci *dlci; |
|
u8 cr; |
|
int address; |
|
/* We have to sneak a look at the packet body to do the FCS. |
|
A somewhat layering violation in the spec */ |
|
|
|
if ((gsm->control & ~PF) == UI) |
|
gsm->fcs = gsm_fcs_add_block(gsm->fcs, gsm->buf, gsm->len); |
|
if (gsm->encoding == 0) { |
|
/* WARNING: gsm->received_fcs is used for |
|
gsm->encoding = 0 only. |
|
In this case it contain the last piece of data |
|
required to generate final CRC */ |
|
gsm->fcs = gsm_fcs_add(gsm->fcs, gsm->received_fcs); |
|
} |
|
if (gsm->fcs != GOOD_FCS) { |
|
gsm->bad_fcs++; |
|
if (debug & 4) |
|
pr_debug("BAD FCS %02x\n", gsm->fcs); |
|
return; |
|
} |
|
address = gsm->address >> 1; |
|
if (address >= NUM_DLCI) |
|
goto invalid; |
|
|
|
cr = gsm->address & 1; /* C/R bit */ |
|
|
|
gsm_print_packet("<--", address, cr, gsm->control, gsm->buf, gsm->len); |
|
|
|
cr ^= 1 - gsm->initiator; /* Flip so 1 always means command */ |
|
dlci = gsm->dlci[address]; |
|
|
|
switch (gsm->control) { |
|
case SABM|PF: |
|
if (cr == 0) |
|
goto invalid; |
|
if (dlci == NULL) |
|
dlci = gsm_dlci_alloc(gsm, address); |
|
if (dlci == NULL) |
|
return; |
|
if (dlci->dead) |
|
gsm_response(gsm, address, DM); |
|
else { |
|
gsm_response(gsm, address, UA); |
|
gsm_dlci_open(dlci); |
|
} |
|
break; |
|
case DISC|PF: |
|
if (cr == 0) |
|
goto invalid; |
|
if (dlci == NULL || dlci->state == DLCI_CLOSED) { |
|
gsm_response(gsm, address, DM); |
|
return; |
|
} |
|
/* Real close complete */ |
|
gsm_response(gsm, address, UA); |
|
gsm_dlci_close(dlci); |
|
break; |
|
case UA: |
|
case UA|PF: |
|
if (cr == 0 || dlci == NULL) |
|
break; |
|
switch (dlci->state) { |
|
case DLCI_CLOSING: |
|
gsm_dlci_close(dlci); |
|
break; |
|
case DLCI_OPENING: |
|
gsm_dlci_open(dlci); |
|
break; |
|
default: |
|
pr_debug("%s: unhandled state: %d\n", __func__, |
|
dlci->state); |
|
break; |
|
} |
|
break; |
|
case DM: /* DM can be valid unsolicited */ |
|
case DM|PF: |
|
if (cr) |
|
goto invalid; |
|
if (dlci == NULL) |
|
return; |
|
gsm_dlci_close(dlci); |
|
break; |
|
case UI: |
|
case UI|PF: |
|
case UIH: |
|
case UIH|PF: |
|
#if 0 |
|
if (cr) |
|
goto invalid; |
|
#endif |
|
if (dlci == NULL || dlci->state != DLCI_OPEN) { |
|
gsm_command(gsm, address, DM|PF); |
|
return; |
|
} |
|
dlci->data(dlci, gsm->buf, gsm->len); |
|
break; |
|
default: |
|
goto invalid; |
|
} |
|
return; |
|
invalid: |
|
gsm->malformed++; |
|
return; |
|
} |
|
|
|
|
|
/** |
|
* gsm0_receive - perform processing for non-transparency |
|
* @gsm: gsm data for this ldisc instance |
|
* @c: character |
|
* |
|
* Receive bytes in gsm mode 0 |
|
*/ |
|
|
|
static void gsm0_receive(struct gsm_mux *gsm, unsigned char c) |
|
{ |
|
unsigned int len; |
|
|
|
switch (gsm->state) { |
|
case GSM_SEARCH: /* SOF marker */ |
|
if (c == GSM0_SOF) { |
|
gsm->state = GSM_ADDRESS; |
|
gsm->address = 0; |
|
gsm->len = 0; |
|
gsm->fcs = INIT_FCS; |
|
} |
|
break; |
|
case GSM_ADDRESS: /* Address EA */ |
|
gsm->fcs = gsm_fcs_add(gsm->fcs, c); |
|
if (gsm_read_ea(&gsm->address, c)) |
|
gsm->state = GSM_CONTROL; |
|
break; |
|
case GSM_CONTROL: /* Control Byte */ |
|
gsm->fcs = gsm_fcs_add(gsm->fcs, c); |
|
gsm->control = c; |
|
gsm->state = GSM_LEN0; |
|
break; |
|
case GSM_LEN0: /* Length EA */ |
|
gsm->fcs = gsm_fcs_add(gsm->fcs, c); |
|
if (gsm_read_ea(&gsm->len, c)) { |
|
if (gsm->len > gsm->mru) { |
|
gsm->bad_size++; |
|
gsm->state = GSM_SEARCH; |
|
break; |
|
} |
|
gsm->count = 0; |
|
if (!gsm->len) |
|
gsm->state = GSM_FCS; |
|
else |
|
gsm->state = GSM_DATA; |
|
break; |
|
} |
|
gsm->state = GSM_LEN1; |
|
break; |
|
case GSM_LEN1: |
|
gsm->fcs = gsm_fcs_add(gsm->fcs, c); |
|
len = c; |
|
gsm->len |= len << 7; |
|
if (gsm->len > gsm->mru) { |
|
gsm->bad_size++; |
|
gsm->state = GSM_SEARCH; |
|
break; |
|
} |
|
gsm->count = 0; |
|
if (!gsm->len) |
|
gsm->state = GSM_FCS; |
|
else |
|
gsm->state = GSM_DATA; |
|
break; |
|
case GSM_DATA: /* Data */ |
|
gsm->buf[gsm->count++] = c; |
|
if (gsm->count == gsm->len) |
|
gsm->state = GSM_FCS; |
|
break; |
|
case GSM_FCS: /* FCS follows the packet */ |
|
gsm->received_fcs = c; |
|
gsm_queue(gsm); |
|
gsm->state = GSM_SSOF; |
|
break; |
|
case GSM_SSOF: |
|
if (c == GSM0_SOF) { |
|
gsm->state = GSM_SEARCH; |
|
break; |
|
} |
|
break; |
|
default: |
|
pr_debug("%s: unhandled state: %d\n", __func__, gsm->state); |
|
break; |
|
} |
|
} |
|
|
|
/** |
|
* gsm1_receive - perform processing for non-transparency |
|
* @gsm: gsm data for this ldisc instance |
|
* @c: character |
|
* |
|
* Receive bytes in mode 1 (Advanced option) |
|
*/ |
|
|
|
static void gsm1_receive(struct gsm_mux *gsm, unsigned char c) |
|
{ |
|
if (c == GSM1_SOF) { |
|
/* EOF is only valid in frame if we have got to the data state |
|
and received at least one byte (the FCS) */ |
|
if (gsm->state == GSM_DATA && gsm->count) { |
|
/* Extract the FCS */ |
|
gsm->count--; |
|
gsm->fcs = gsm_fcs_add(gsm->fcs, gsm->buf[gsm->count]); |
|
gsm->len = gsm->count; |
|
gsm_queue(gsm); |
|
gsm->state = GSM_START; |
|
return; |
|
} |
|
/* Any partial frame was a runt so go back to start */ |
|
if (gsm->state != GSM_START) { |
|
gsm->malformed++; |
|
gsm->state = GSM_START; |
|
} |
|
/* A SOF in GSM_START means we are still reading idling or |
|
framing bytes */ |
|
return; |
|
} |
|
|
|
if (c == GSM1_ESCAPE) { |
|
gsm->escape = true; |
|
return; |
|
} |
|
|
|
/* Only an unescaped SOF gets us out of GSM search */ |
|
if (gsm->state == GSM_SEARCH) |
|
return; |
|
|
|
if (gsm->escape) { |
|
c ^= GSM1_ESCAPE_BITS; |
|
gsm->escape = false; |
|
} |
|
switch (gsm->state) { |
|
case GSM_START: /* First byte after SOF */ |
|
gsm->address = 0; |
|
gsm->state = GSM_ADDRESS; |
|
gsm->fcs = INIT_FCS; |
|
fallthrough; |
|
case GSM_ADDRESS: /* Address continuation */ |
|
gsm->fcs = gsm_fcs_add(gsm->fcs, c); |
|
if (gsm_read_ea(&gsm->address, c)) |
|
gsm->state = GSM_CONTROL; |
|
break; |
|
case GSM_CONTROL: /* Control Byte */ |
|
gsm->fcs = gsm_fcs_add(gsm->fcs, c); |
|
gsm->control = c; |
|
gsm->count = 0; |
|
gsm->state = GSM_DATA; |
|
break; |
|
case GSM_DATA: /* Data */ |
|
if (gsm->count > gsm->mru) { /* Allow one for the FCS */ |
|
gsm->state = GSM_OVERRUN; |
|
gsm->bad_size++; |
|
} else |
|
gsm->buf[gsm->count++] = c; |
|
break; |
|
case GSM_OVERRUN: /* Over-long - eg a dropped SOF */ |
|
break; |
|
default: |
|
pr_debug("%s: unhandled state: %d\n", __func__, gsm->state); |
|
break; |
|
} |
|
} |
|
|
|
/** |
|
* gsm_error - handle tty error |
|
* @gsm: ldisc data |
|
* @data: byte received (may be invalid) |
|
* @flag: error received |
|
* |
|
* Handle an error in the receipt of data for a frame. Currently we just |
|
* go back to hunting for a SOF. |
|
* |
|
* FIXME: better diagnostics ? |
|
*/ |
|
|
|
static void gsm_error(struct gsm_mux *gsm, |
|
unsigned char data, unsigned char flag) |
|
{ |
|
gsm->state = GSM_SEARCH; |
|
gsm->io_error++; |
|
} |
|
|
|
static int gsm_disconnect(struct gsm_mux *gsm) |
|
{ |
|
struct gsm_dlci *dlci = gsm->dlci[0]; |
|
struct gsm_control *gc; |
|
|
|
if (!dlci) |
|
return 0; |
|
|
|
/* In theory disconnecting DLCI 0 is sufficient but for some |
|
modems this is apparently not the case. */ |
|
gc = gsm_control_send(gsm, CMD_CLD, NULL, 0); |
|
if (gc) |
|
gsm_control_wait(gsm, gc); |
|
|
|
del_timer_sync(&gsm->t2_timer); |
|
/* Now we are sure T2 has stopped */ |
|
|
|
gsm_dlci_begin_close(dlci); |
|
wait_event_interruptible(gsm->event, |
|
dlci->state == DLCI_CLOSED); |
|
|
|
if (signal_pending(current)) |
|
return -EINTR; |
|
|
|
return 0; |
|
} |
|
|
|
/** |
|
* gsm_cleanup_mux - generic GSM protocol cleanup |
|
* @gsm: our mux |
|
* |
|
* Clean up the bits of the mux which are the same for all framing |
|
* protocols. Remove the mux from the mux table, stop all the timers |
|
* and then shut down each device hanging up the channels as we go. |
|
*/ |
|
|
|
static void gsm_cleanup_mux(struct gsm_mux *gsm) |
|
{ |
|
int i; |
|
struct gsm_dlci *dlci = gsm->dlci[0]; |
|
struct gsm_msg *txq, *ntxq; |
|
|
|
gsm->dead = true; |
|
|
|
spin_lock(&gsm_mux_lock); |
|
for (i = 0; i < MAX_MUX; i++) { |
|
if (gsm_mux[i] == gsm) { |
|
gsm_mux[i] = NULL; |
|
break; |
|
} |
|
} |
|
spin_unlock(&gsm_mux_lock); |
|
/* open failed before registering => nothing to do */ |
|
if (i == MAX_MUX) |
|
return; |
|
|
|
del_timer_sync(&gsm->t2_timer); |
|
/* Now we are sure T2 has stopped */ |
|
if (dlci) |
|
dlci->dead = true; |
|
|
|
/* Free up any link layer users */ |
|
mutex_lock(&gsm->mutex); |
|
for (i = 0; i < NUM_DLCI; i++) |
|
if (gsm->dlci[i]) |
|
gsm_dlci_release(gsm->dlci[i]); |
|
mutex_unlock(&gsm->mutex); |
|
/* Now wipe the queues */ |
|
list_for_each_entry_safe(txq, ntxq, &gsm->tx_list, list) |
|
kfree(txq); |
|
INIT_LIST_HEAD(&gsm->tx_list); |
|
} |
|
|
|
/** |
|
* gsm_activate_mux - generic GSM setup |
|
* @gsm: our mux |
|
* |
|
* Set up the bits of the mux which are the same for all framing |
|
* protocols. Add the mux to the mux table so it can be opened and |
|
* finally kick off connecting to DLCI 0 on the modem. |
|
*/ |
|
|
|
static int gsm_activate_mux(struct gsm_mux *gsm) |
|
{ |
|
struct gsm_dlci *dlci; |
|
int i = 0; |
|
|
|
timer_setup(&gsm->t2_timer, gsm_control_retransmit, 0); |
|
init_waitqueue_head(&gsm->event); |
|
spin_lock_init(&gsm->control_lock); |
|
spin_lock_init(&gsm->tx_lock); |
|
|
|
if (gsm->encoding == 0) |
|
gsm->receive = gsm0_receive; |
|
else |
|
gsm->receive = gsm1_receive; |
|
|
|
spin_lock(&gsm_mux_lock); |
|
for (i = 0; i < MAX_MUX; i++) { |
|
if (gsm_mux[i] == NULL) { |
|
gsm->num = i; |
|
gsm_mux[i] = gsm; |
|
break; |
|
} |
|
} |
|
spin_unlock(&gsm_mux_lock); |
|
if (i == MAX_MUX) |
|
return -EBUSY; |
|
|
|
dlci = gsm_dlci_alloc(gsm, 0); |
|
if (dlci == NULL) |
|
return -ENOMEM; |
|
gsm->dead = false; /* Tty opens are now permissible */ |
|
return 0; |
|
} |
|
|
|
/** |
|
* gsm_free_mux - free up a mux |
|
* @gsm: mux to free |
|
* |
|
* Dispose of allocated resources for a dead mux |
|
*/ |
|
static void gsm_free_mux(struct gsm_mux *gsm) |
|
{ |
|
kfree(gsm->txframe); |
|
kfree(gsm->buf); |
|
kfree(gsm); |
|
} |
|
|
|
/** |
|
* gsm_free_muxr - free up a mux |
|
* @ref: kreference to the mux to free |
|
* |
|
* Dispose of allocated resources for a dead mux |
|
*/ |
|
static void gsm_free_muxr(struct kref *ref) |
|
{ |
|
struct gsm_mux *gsm = container_of(ref, struct gsm_mux, ref); |
|
gsm_free_mux(gsm); |
|
} |
|
|
|
static inline void mux_get(struct gsm_mux *gsm) |
|
{ |
|
kref_get(&gsm->ref); |
|
} |
|
|
|
static inline void mux_put(struct gsm_mux *gsm) |
|
{ |
|
kref_put(&gsm->ref, gsm_free_muxr); |
|
} |
|
|
|
static inline unsigned int mux_num_to_base(struct gsm_mux *gsm) |
|
{ |
|
return gsm->num * NUM_DLCI; |
|
} |
|
|
|
static inline unsigned int mux_line_to_num(unsigned int line) |
|
{ |
|
return line / NUM_DLCI; |
|
} |
|
|
|
/** |
|
* gsm_alloc_mux - allocate a mux |
|
* |
|
* Creates a new mux ready for activation. |
|
*/ |
|
|
|
static struct gsm_mux *gsm_alloc_mux(void) |
|
{ |
|
struct gsm_mux *gsm = kzalloc(sizeof(struct gsm_mux), GFP_KERNEL); |
|
if (gsm == NULL) |
|
return NULL; |
|
gsm->buf = kmalloc(MAX_MRU + 1, GFP_KERNEL); |
|
if (gsm->buf == NULL) { |
|
kfree(gsm); |
|
return NULL; |
|
} |
|
gsm->txframe = kmalloc(2 * MAX_MRU + 2, GFP_KERNEL); |
|
if (gsm->txframe == NULL) { |
|
kfree(gsm->buf); |
|
kfree(gsm); |
|
return NULL; |
|
} |
|
spin_lock_init(&gsm->lock); |
|
mutex_init(&gsm->mutex); |
|
kref_init(&gsm->ref); |
|
INIT_LIST_HEAD(&gsm->tx_list); |
|
|
|
gsm->t1 = T1; |
|
gsm->t2 = T2; |
|
gsm->n2 = N2; |
|
gsm->ftype = UIH; |
|
gsm->adaption = 1; |
|
gsm->encoding = 1; |
|
gsm->mru = 64; /* Default to encoding 1 so these should be 64 */ |
|
gsm->mtu = 64; |
|
gsm->dead = true; /* Avoid early tty opens */ |
|
|
|
return gsm; |
|
} |
|
|
|
static void gsm_copy_config_values(struct gsm_mux *gsm, |
|
struct gsm_config *c) |
|
{ |
|
memset(c, 0, sizeof(*c)); |
|
c->adaption = gsm->adaption; |
|
c->encapsulation = gsm->encoding; |
|
c->initiator = gsm->initiator; |
|
c->t1 = gsm->t1; |
|
c->t2 = gsm->t2; |
|
c->t3 = 0; /* Not supported */ |
|
c->n2 = gsm->n2; |
|
if (gsm->ftype == UIH) |
|
c->i = 1; |
|
else |
|
c->i = 2; |
|
pr_debug("Ftype %d i %d\n", gsm->ftype, c->i); |
|
c->mru = gsm->mru; |
|
c->mtu = gsm->mtu; |
|
c->k = 0; |
|
} |
|
|
|
static int gsm_config(struct gsm_mux *gsm, struct gsm_config *c) |
|
{ |
|
int need_close = 0; |
|
int need_restart = 0; |
|
|
|
/* Stuff we don't support yet - UI or I frame transport, windowing */ |
|
if ((c->adaption != 1 && c->adaption != 2) || c->k) |
|
return -EOPNOTSUPP; |
|
/* Check the MRU/MTU range looks sane */ |
|
if (c->mru > MAX_MRU || c->mtu > MAX_MTU || c->mru < 8 || c->mtu < 8) |
|
return -EINVAL; |
|
if (c->n2 < 3) |
|
return -EINVAL; |
|
if (c->encapsulation > 1) /* Basic, advanced, no I */ |
|
return -EINVAL; |
|
if (c->initiator > 1) |
|
return -EINVAL; |
|
if (c->i == 0 || c->i > 2) /* UIH and UI only */ |
|
return -EINVAL; |
|
/* |
|
* See what is needed for reconfiguration |
|
*/ |
|
|
|
/* Timing fields */ |
|
if (c->t1 != 0 && c->t1 != gsm->t1) |
|
need_restart = 1; |
|
if (c->t2 != 0 && c->t2 != gsm->t2) |
|
need_restart = 1; |
|
if (c->encapsulation != gsm->encoding) |
|
need_restart = 1; |
|
if (c->adaption != gsm->adaption) |
|
need_restart = 1; |
|
/* Requires care */ |
|
if (c->initiator != gsm->initiator) |
|
need_close = 1; |
|
if (c->mru != gsm->mru) |
|
need_restart = 1; |
|
if (c->mtu != gsm->mtu) |
|
need_restart = 1; |
|
|
|
/* |
|
* Close down what is needed, restart and initiate the new |
|
* configuration |
|
*/ |
|
|
|
if (need_close || need_restart) { |
|
int ret; |
|
|
|
ret = gsm_disconnect(gsm); |
|
|
|
if (ret) |
|
return ret; |
|
} |
|
if (need_restart) |
|
gsm_cleanup_mux(gsm); |
|
|
|
gsm->initiator = c->initiator; |
|
gsm->mru = c->mru; |
|
gsm->mtu = c->mtu; |
|
gsm->encoding = c->encapsulation; |
|
gsm->adaption = c->adaption; |
|
gsm->n2 = c->n2; |
|
|
|
if (c->i == 1) |
|
gsm->ftype = UIH; |
|
else if (c->i == 2) |
|
gsm->ftype = UI; |
|
|
|
if (c->t1) |
|
gsm->t1 = c->t1; |
|
if (c->t2) |
|
gsm->t2 = c->t2; |
|
|
|
/* |
|
* FIXME: We need to separate activation/deactivation from adding |
|
* and removing from the mux array |
|
*/ |
|
if (need_restart) |
|
gsm_activate_mux(gsm); |
|
if (gsm->initiator && need_close) |
|
gsm_dlci_begin_open(gsm->dlci[0]); |
|
return 0; |
|
} |
|
|
|
/** |
|
* gsmld_output - write to link |
|
* @gsm: our mux |
|
* @data: bytes to output |
|
* @len: size |
|
* |
|
* Write a block of data from the GSM mux to the data channel. This |
|
* will eventually be serialized from above but at the moment isn't. |
|
*/ |
|
|
|
static int gsmld_output(struct gsm_mux *gsm, u8 *data, int len) |
|
{ |
|
if (tty_write_room(gsm->tty) < len) { |
|
set_bit(TTY_DO_WRITE_WAKEUP, &gsm->tty->flags); |
|
return -ENOSPC; |
|
} |
|
if (debug & 4) |
|
print_hex_dump_bytes("gsmld_output: ", DUMP_PREFIX_OFFSET, |
|
data, len); |
|
gsm->tty->ops->write(gsm->tty, data, len); |
|
return len; |
|
} |
|
|
|
/** |
|
* gsmld_attach_gsm - mode set up |
|
* @tty: our tty structure |
|
* @gsm: our mux |
|
* |
|
* Set up the MUX for basic mode and commence connecting to the |
|
* modem. Currently called from the line discipline set up but |
|
* will need moving to an ioctl path. |
|
*/ |
|
|
|
static int gsmld_attach_gsm(struct tty_struct *tty, struct gsm_mux *gsm) |
|
{ |
|
unsigned int base; |
|
int ret, i; |
|
|
|
gsm->tty = tty_kref_get(tty); |
|
ret = gsm_activate_mux(gsm); |
|
if (ret != 0) |
|
tty_kref_put(gsm->tty); |
|
else { |
|
/* Don't register device 0 - this is the control channel and not |
|
a usable tty interface */ |
|
base = mux_num_to_base(gsm); /* Base for this MUX */ |
|
for (i = 1; i < NUM_DLCI; i++) { |
|
struct device *dev; |
|
|
|
dev = tty_register_device(gsm_tty_driver, |
|
base + i, NULL); |
|
if (IS_ERR(dev)) { |
|
for (i--; i >= 1; i--) |
|
tty_unregister_device(gsm_tty_driver, |
|
base + i); |
|
return PTR_ERR(dev); |
|
} |
|
} |
|
} |
|
return ret; |
|
} |
|
|
|
|
|
/** |
|
* gsmld_detach_gsm - stop doing 0710 mux |
|
* @tty: tty attached to the mux |
|
* @gsm: mux |
|
* |
|
* Shutdown and then clean up the resources used by the line discipline |
|
*/ |
|
|
|
static void gsmld_detach_gsm(struct tty_struct *tty, struct gsm_mux *gsm) |
|
{ |
|
unsigned int base = mux_num_to_base(gsm); /* Base for this MUX */ |
|
int i; |
|
|
|
WARN_ON(tty != gsm->tty); |
|
for (i = 1; i < NUM_DLCI; i++) |
|
tty_unregister_device(gsm_tty_driver, base + i); |
|
gsm_cleanup_mux(gsm); |
|
tty_kref_put(gsm->tty); |
|
gsm->tty = NULL; |
|
} |
|
|
|
static void gsmld_receive_buf(struct tty_struct *tty, const unsigned char *cp, |
|
const char *fp, int count) |
|
{ |
|
struct gsm_mux *gsm = tty->disc_data; |
|
char flags = TTY_NORMAL; |
|
|
|
if (debug & 4) |
|
print_hex_dump_bytes("gsmld_receive: ", DUMP_PREFIX_OFFSET, |
|
cp, count); |
|
|
|
for (; count; count--, cp++) { |
|
if (fp) |
|
flags = *fp++; |
|
switch (flags) { |
|
case TTY_NORMAL: |
|
gsm->receive(gsm, *cp); |
|
break; |
|
case TTY_OVERRUN: |
|
case TTY_BREAK: |
|
case TTY_PARITY: |
|
case TTY_FRAME: |
|
gsm_error(gsm, *cp, flags); |
|
break; |
|
default: |
|
WARN_ONCE(1, "%s: unknown flag %d\n", |
|
tty_name(tty), flags); |
|
break; |
|
} |
|
} |
|
/* FASYNC if needed ? */ |
|
/* If clogged call tty_throttle(tty); */ |
|
} |
|
|
|
/** |
|
* gsmld_flush_buffer - clean input queue |
|
* @tty: terminal device |
|
* |
|
* Flush the input buffer. Called when the line discipline is |
|
* being closed, when the tty layer wants the buffer flushed (eg |
|
* at hangup). |
|
*/ |
|
|
|
static void gsmld_flush_buffer(struct tty_struct *tty) |
|
{ |
|
} |
|
|
|
/** |
|
* gsmld_close - close the ldisc for this tty |
|
* @tty: device |
|
* |
|
* Called from the terminal layer when this line discipline is |
|
* being shut down, either because of a close or becsuse of a |
|
* discipline change. The function will not be called while other |
|
* ldisc methods are in progress. |
|
*/ |
|
|
|
static void gsmld_close(struct tty_struct *tty) |
|
{ |
|
struct gsm_mux *gsm = tty->disc_data; |
|
|
|
gsmld_detach_gsm(tty, gsm); |
|
|
|
gsmld_flush_buffer(tty); |
|
/* Do other clean up here */ |
|
mux_put(gsm); |
|
} |
|
|
|
/** |
|
* gsmld_open - open an ldisc |
|
* @tty: terminal to open |
|
* |
|
* Called when this line discipline is being attached to the |
|
* terminal device. Can sleep. Called serialized so that no |
|
* other events will occur in parallel. No further open will occur |
|
* until a close. |
|
*/ |
|
|
|
static int gsmld_open(struct tty_struct *tty) |
|
{ |
|
struct gsm_mux *gsm; |
|
int ret; |
|
|
|
if (tty->ops->write == NULL) |
|
return -EINVAL; |
|
|
|
/* Attach our ldisc data */ |
|
gsm = gsm_alloc_mux(); |
|
if (gsm == NULL) |
|
return -ENOMEM; |
|
|
|
tty->disc_data = gsm; |
|
tty->receive_room = 65536; |
|
|
|
/* Attach the initial passive connection */ |
|
gsm->encoding = 1; |
|
|
|
ret = gsmld_attach_gsm(tty, gsm); |
|
if (ret != 0) { |
|
gsm_cleanup_mux(gsm); |
|
mux_put(gsm); |
|
} |
|
return ret; |
|
} |
|
|
|
/** |
|
* gsmld_write_wakeup - asynchronous I/O notifier |
|
* @tty: tty device |
|
* |
|
* Required for the ptys, serial driver etc. since processes |
|
* that attach themselves to the master and rely on ASYNC |
|
* IO must be woken up |
|
*/ |
|
|
|
static void gsmld_write_wakeup(struct tty_struct *tty) |
|
{ |
|
struct gsm_mux *gsm = tty->disc_data; |
|
unsigned long flags; |
|
|
|
/* Queue poll */ |
|
clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags); |
|
spin_lock_irqsave(&gsm->tx_lock, flags); |
|
gsm_data_kick(gsm, NULL); |
|
if (gsm->tx_bytes < TX_THRESH_LO) { |
|
gsm_dlci_data_sweep(gsm); |
|
} |
|
spin_unlock_irqrestore(&gsm->tx_lock, flags); |
|
} |
|
|
|
/** |
|
* gsmld_read - read function for tty |
|
* @tty: tty device |
|
* @file: file object |
|
* @buf: userspace buffer pointer |
|
* @nr: size of I/O |
|
* @cookie: unused |
|
* @offset: unused |
|
* |
|
* Perform reads for the line discipline. We are guaranteed that the |
|
* line discipline will not be closed under us but we may get multiple |
|
* parallel readers and must handle this ourselves. We may also get |
|
* a hangup. Always called in user context, may sleep. |
|
* |
|
* This code must be sure never to sleep through a hangup. |
|
*/ |
|
|
|
static ssize_t gsmld_read(struct tty_struct *tty, struct file *file, |
|
unsigned char *buf, size_t nr, |
|
void **cookie, unsigned long offset) |
|
{ |
|
return -EOPNOTSUPP; |
|
} |
|
|
|
/** |
|
* gsmld_write - write function for tty |
|
* @tty: tty device |
|
* @file: file object |
|
* @buf: userspace buffer pointer |
|
* @nr: size of I/O |
|
* |
|
* Called when the owner of the device wants to send a frame |
|
* itself (or some other control data). The data is transferred |
|
* as-is and must be properly framed and checksummed as appropriate |
|
* by userspace. Frames are either sent whole or not at all as this |
|
* avoids pain user side. |
|
*/ |
|
|
|
static ssize_t gsmld_write(struct tty_struct *tty, struct file *file, |
|
const unsigned char *buf, size_t nr) |
|
{ |
|
int space = tty_write_room(tty); |
|
if (space >= nr) |
|
return tty->ops->write(tty, buf, nr); |
|
set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags); |
|
return -ENOBUFS; |
|
} |
|
|
|
/** |
|
* gsmld_poll - poll method for N_GSM0710 |
|
* @tty: terminal device |
|
* @file: file accessing it |
|
* @wait: poll table |
|
* |
|
* Called when the line discipline is asked to poll() for data or |
|
* for special events. This code is not serialized with respect to |
|
* other events save open/close. |
|
* |
|
* This code must be sure never to sleep through a hangup. |
|
* Called without the kernel lock held - fine |
|
*/ |
|
|
|
static __poll_t gsmld_poll(struct tty_struct *tty, struct file *file, |
|
poll_table *wait) |
|
{ |
|
__poll_t mask = 0; |
|
struct gsm_mux *gsm = tty->disc_data; |
|
|
|
poll_wait(file, &tty->read_wait, wait); |
|
poll_wait(file, &tty->write_wait, wait); |
|
if (tty_hung_up_p(file)) |
|
mask |= EPOLLHUP; |
|
if (!tty_is_writelocked(tty) && tty_write_room(tty) > 0) |
|
mask |= EPOLLOUT | EPOLLWRNORM; |
|
if (gsm->dead) |
|
mask |= EPOLLHUP; |
|
return mask; |
|
} |
|
|
|
static int gsmld_ioctl(struct tty_struct *tty, struct file *file, |
|
unsigned int cmd, unsigned long arg) |
|
{ |
|
struct gsm_config c; |
|
struct gsm_mux *gsm = tty->disc_data; |
|
unsigned int base; |
|
|
|
switch (cmd) { |
|
case GSMIOC_GETCONF: |
|
gsm_copy_config_values(gsm, &c); |
|
if (copy_to_user((void __user *)arg, &c, sizeof(c))) |
|
return -EFAULT; |
|
return 0; |
|
case GSMIOC_SETCONF: |
|
if (copy_from_user(&c, (void __user *)arg, sizeof(c))) |
|
return -EFAULT; |
|
return gsm_config(gsm, &c); |
|
case GSMIOC_GETFIRST: |
|
base = mux_num_to_base(gsm); |
|
return put_user(base + 1, (__u32 __user *)arg); |
|
default: |
|
return n_tty_ioctl_helper(tty, file, cmd, arg); |
|
} |
|
} |
|
|
|
/* |
|
* Network interface |
|
* |
|
*/ |
|
|
|
static int gsm_mux_net_open(struct net_device *net) |
|
{ |
|
pr_debug("%s called\n", __func__); |
|
netif_start_queue(net); |
|
return 0; |
|
} |
|
|
|
static int gsm_mux_net_close(struct net_device *net) |
|
{ |
|
netif_stop_queue(net); |
|
return 0; |
|
} |
|
|
|
static void dlci_net_free(struct gsm_dlci *dlci) |
|
{ |
|
if (!dlci->net) { |
|
WARN_ON(1); |
|
return; |
|
} |
|
dlci->adaption = dlci->prev_adaption; |
|
dlci->data = dlci->prev_data; |
|
free_netdev(dlci->net); |
|
dlci->net = NULL; |
|
} |
|
static void net_free(struct kref *ref) |
|
{ |
|
struct gsm_mux_net *mux_net; |
|
struct gsm_dlci *dlci; |
|
|
|
mux_net = container_of(ref, struct gsm_mux_net, ref); |
|
dlci = mux_net->dlci; |
|
|
|
if (dlci->net) { |
|
unregister_netdev(dlci->net); |
|
dlci_net_free(dlci); |
|
} |
|
} |
|
|
|
static inline void muxnet_get(struct gsm_mux_net *mux_net) |
|
{ |
|
kref_get(&mux_net->ref); |
|
} |
|
|
|
static inline void muxnet_put(struct gsm_mux_net *mux_net) |
|
{ |
|
kref_put(&mux_net->ref, net_free); |
|
} |
|
|
|
static netdev_tx_t gsm_mux_net_start_xmit(struct sk_buff *skb, |
|
struct net_device *net) |
|
{ |
|
struct gsm_mux_net *mux_net = netdev_priv(net); |
|
struct gsm_dlci *dlci = mux_net->dlci; |
|
muxnet_get(mux_net); |
|
|
|
skb_queue_head(&dlci->skb_list, skb); |
|
net->stats.tx_packets++; |
|
net->stats.tx_bytes += skb->len; |
|
gsm_dlci_data_kick(dlci); |
|
/* And tell the kernel when the last transmit started. */ |
|
netif_trans_update(net); |
|
muxnet_put(mux_net); |
|
return NETDEV_TX_OK; |
|
} |
|
|
|
/* called when a packet did not ack after watchdogtimeout */ |
|
static void gsm_mux_net_tx_timeout(struct net_device *net, unsigned int txqueue) |
|
{ |
|
/* Tell syslog we are hosed. */ |
|
dev_dbg(&net->dev, "Tx timed out.\n"); |
|
|
|
/* Update statistics */ |
|
net->stats.tx_errors++; |
|
} |
|
|
|
static void gsm_mux_rx_netchar(struct gsm_dlci *dlci, |
|
const unsigned char *in_buf, int size) |
|
{ |
|
struct net_device *net = dlci->net; |
|
struct sk_buff *skb; |
|
struct gsm_mux_net *mux_net = netdev_priv(net); |
|
muxnet_get(mux_net); |
|
|
|
/* Allocate an sk_buff */ |
|
skb = dev_alloc_skb(size + NET_IP_ALIGN); |
|
if (!skb) { |
|
/* We got no receive buffer. */ |
|
net->stats.rx_dropped++; |
|
muxnet_put(mux_net); |
|
return; |
|
} |
|
skb_reserve(skb, NET_IP_ALIGN); |
|
skb_put_data(skb, in_buf, size); |
|
|
|
skb->dev = net; |
|
skb->protocol = htons(ETH_P_IP); |
|
|
|
/* Ship it off to the kernel */ |
|
netif_rx(skb); |
|
|
|
/* update out statistics */ |
|
net->stats.rx_packets++; |
|
net->stats.rx_bytes += size; |
|
muxnet_put(mux_net); |
|
return; |
|
} |
|
|
|
static void gsm_mux_net_init(struct net_device *net) |
|
{ |
|
static const struct net_device_ops gsm_netdev_ops = { |
|
.ndo_open = gsm_mux_net_open, |
|
.ndo_stop = gsm_mux_net_close, |
|
.ndo_start_xmit = gsm_mux_net_start_xmit, |
|
.ndo_tx_timeout = gsm_mux_net_tx_timeout, |
|
}; |
|
|
|
net->netdev_ops = &gsm_netdev_ops; |
|
|
|
/* fill in the other fields */ |
|
net->watchdog_timeo = GSM_NET_TX_TIMEOUT; |
|
net->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST; |
|
net->type = ARPHRD_NONE; |
|
net->tx_queue_len = 10; |
|
} |
|
|
|
|
|
/* caller holds the dlci mutex */ |
|
static void gsm_destroy_network(struct gsm_dlci *dlci) |
|
{ |
|
struct gsm_mux_net *mux_net; |
|
|
|
pr_debug("destroy network interface\n"); |
|
if (!dlci->net) |
|
return; |
|
mux_net = netdev_priv(dlci->net); |
|
muxnet_put(mux_net); |
|
} |
|
|
|
|
|
/* caller holds the dlci mutex */ |
|
static int gsm_create_network(struct gsm_dlci *dlci, struct gsm_netconfig *nc) |
|
{ |
|
char *netname; |
|
int retval = 0; |
|
struct net_device *net; |
|
struct gsm_mux_net *mux_net; |
|
|
|
if (!capable(CAP_NET_ADMIN)) |
|
return -EPERM; |
|
|
|
/* Already in a non tty mode */ |
|
if (dlci->adaption > 2) |
|
return -EBUSY; |
|
|
|
if (nc->protocol != htons(ETH_P_IP)) |
|
return -EPROTONOSUPPORT; |
|
|
|
if (nc->adaption != 3 && nc->adaption != 4) |
|
return -EPROTONOSUPPORT; |
|
|
|
pr_debug("create network interface\n"); |
|
|
|
netname = "gsm%d"; |
|
if (nc->if_name[0] != '\0') |
|
netname = nc->if_name; |
|
net = alloc_netdev(sizeof(struct gsm_mux_net), netname, |
|
NET_NAME_UNKNOWN, gsm_mux_net_init); |
|
if (!net) { |
|
pr_err("alloc_netdev failed\n"); |
|
return -ENOMEM; |
|
} |
|
net->mtu = dlci->gsm->mtu; |
|
net->min_mtu = 8; |
|
net->max_mtu = dlci->gsm->mtu; |
|
mux_net = netdev_priv(net); |
|
mux_net->dlci = dlci; |
|
kref_init(&mux_net->ref); |
|
strncpy(nc->if_name, net->name, IFNAMSIZ); /* return net name */ |
|
|
|
/* reconfigure dlci for network */ |
|
dlci->prev_adaption = dlci->adaption; |
|
dlci->prev_data = dlci->data; |
|
dlci->adaption = nc->adaption; |
|
dlci->data = gsm_mux_rx_netchar; |
|
dlci->net = net; |
|
|
|
pr_debug("register netdev\n"); |
|
retval = register_netdev(net); |
|
if (retval) { |
|
pr_err("network register fail %d\n", retval); |
|
dlci_net_free(dlci); |
|
return retval; |
|
} |
|
return net->ifindex; /* return network index */ |
|
} |
|
|
|
/* Line discipline for real tty */ |
|
static struct tty_ldisc_ops tty_ldisc_packet = { |
|
.owner = THIS_MODULE, |
|
.num = N_GSM0710, |
|
.name = "n_gsm", |
|
.open = gsmld_open, |
|
.close = gsmld_close, |
|
.flush_buffer = gsmld_flush_buffer, |
|
.read = gsmld_read, |
|
.write = gsmld_write, |
|
.ioctl = gsmld_ioctl, |
|
.poll = gsmld_poll, |
|
.receive_buf = gsmld_receive_buf, |
|
.write_wakeup = gsmld_write_wakeup |
|
}; |
|
|
|
/* |
|
* Virtual tty side |
|
*/ |
|
|
|
#define TX_SIZE 512 |
|
|
|
static int gsmtty_modem_update(struct gsm_dlci *dlci, u8 brk) |
|
{ |
|
u8 modembits[5]; |
|
struct gsm_control *ctrl; |
|
int len = 2; |
|
|
|
if (brk) |
|
len++; |
|
|
|
modembits[0] = len << 1 | EA; /* Data bytes */ |
|
modembits[1] = dlci->addr << 2 | 3; /* DLCI, EA, 1 */ |
|
modembits[2] = gsm_encode_modem(dlci) << 1 | EA; |
|
if (brk) |
|
modembits[3] = brk << 4 | 2 | EA; /* Valid, EA */ |
|
ctrl = gsm_control_send(dlci->gsm, CMD_MSC, modembits, len + 1); |
|
if (ctrl == NULL) |
|
return -ENOMEM; |
|
return gsm_control_wait(dlci->gsm, ctrl); |
|
} |
|
|
|
static int gsm_carrier_raised(struct tty_port *port) |
|
{ |
|
struct gsm_dlci *dlci = container_of(port, struct gsm_dlci, port); |
|
struct gsm_mux *gsm = dlci->gsm; |
|
|
|
/* Not yet open so no carrier info */ |
|
if (dlci->state != DLCI_OPEN) |
|
return 0; |
|
if (debug & 2) |
|
return 1; |
|
|
|
/* |
|
* Basic mode with control channel in ADM mode may not respond |
|
* to CMD_MSC at all and modem_rx is empty. |
|
*/ |
|
if (gsm->encoding == 0 && gsm->dlci[0]->mode == DLCI_MODE_ADM && |
|
!dlci->modem_rx) |
|
return 1; |
|
|
|
return dlci->modem_rx & TIOCM_CD; |
|
} |
|
|
|
static void gsm_dtr_rts(struct tty_port *port, int onoff) |
|
{ |
|
struct gsm_dlci *dlci = container_of(port, struct gsm_dlci, port); |
|
unsigned int modem_tx = dlci->modem_tx; |
|
if (onoff) |
|
modem_tx |= TIOCM_DTR | TIOCM_RTS; |
|
else |
|
modem_tx &= ~(TIOCM_DTR | TIOCM_RTS); |
|
if (modem_tx != dlci->modem_tx) { |
|
dlci->modem_tx = modem_tx; |
|
gsmtty_modem_update(dlci, 0); |
|
} |
|
} |
|
|
|
static const struct tty_port_operations gsm_port_ops = { |
|
.carrier_raised = gsm_carrier_raised, |
|
.dtr_rts = gsm_dtr_rts, |
|
.destruct = gsm_dlci_free, |
|
}; |
|
|
|
static int gsmtty_install(struct tty_driver *driver, struct tty_struct *tty) |
|
{ |
|
struct gsm_mux *gsm; |
|
struct gsm_dlci *dlci; |
|
unsigned int line = tty->index; |
|
unsigned int mux = mux_line_to_num(line); |
|
bool alloc = false; |
|
int ret; |
|
|
|
line = line & 0x3F; |
|
|
|
if (mux >= MAX_MUX) |
|
return -ENXIO; |
|
/* FIXME: we need to lock gsm_mux for lifetimes of ttys eventually */ |
|
if (gsm_mux[mux] == NULL) |
|
return -EUNATCH; |
|
if (line == 0 || line > 61) /* 62/63 reserved */ |
|
return -ECHRNG; |
|
gsm = gsm_mux[mux]; |
|
if (gsm->dead) |
|
return -EL2HLT; |
|
/* If DLCI 0 is not yet fully open return an error. |
|
This is ok from a locking |
|
perspective as we don't have to worry about this |
|
if DLCI0 is lost */ |
|
mutex_lock(&gsm->mutex); |
|
if (gsm->dlci[0] && gsm->dlci[0]->state != DLCI_OPEN) { |
|
mutex_unlock(&gsm->mutex); |
|
return -EL2NSYNC; |
|
} |
|
dlci = gsm->dlci[line]; |
|
if (dlci == NULL) { |
|
alloc = true; |
|
dlci = gsm_dlci_alloc(gsm, line); |
|
} |
|
if (dlci == NULL) { |
|
mutex_unlock(&gsm->mutex); |
|
return -ENOMEM; |
|
} |
|
ret = tty_port_install(&dlci->port, driver, tty); |
|
if (ret) { |
|
if (alloc) |
|
dlci_put(dlci); |
|
mutex_unlock(&gsm->mutex); |
|
return ret; |
|
} |
|
|
|
dlci_get(dlci); |
|
dlci_get(gsm->dlci[0]); |
|
mux_get(gsm); |
|
tty->driver_data = dlci; |
|
mutex_unlock(&gsm->mutex); |
|
|
|
return 0; |
|
} |
|
|
|
static int gsmtty_open(struct tty_struct *tty, struct file *filp) |
|
{ |
|
struct gsm_dlci *dlci = tty->driver_data; |
|
struct tty_port *port = &dlci->port; |
|
|
|
port->count++; |
|
tty_port_tty_set(port, tty); |
|
|
|
dlci->modem_rx = 0; |
|
/* We could in theory open and close before we wait - eg if we get |
|
a DM straight back. This is ok as that will have caused a hangup */ |
|
tty_port_set_initialized(port, 1); |
|
/* Start sending off SABM messages */ |
|
gsm_dlci_begin_open(dlci); |
|
/* And wait for virtual carrier */ |
|
return tty_port_block_til_ready(port, tty, filp); |
|
} |
|
|
|
static void gsmtty_close(struct tty_struct *tty, struct file *filp) |
|
{ |
|
struct gsm_dlci *dlci = tty->driver_data; |
|
|
|
if (dlci == NULL) |
|
return; |
|
if (dlci->state == DLCI_CLOSED) |
|
return; |
|
mutex_lock(&dlci->mutex); |
|
gsm_destroy_network(dlci); |
|
mutex_unlock(&dlci->mutex); |
|
if (tty_port_close_start(&dlci->port, tty, filp) == 0) |
|
return; |
|
gsm_dlci_begin_close(dlci); |
|
if (tty_port_initialized(&dlci->port) && C_HUPCL(tty)) |
|
tty_port_lower_dtr_rts(&dlci->port); |
|
tty_port_close_end(&dlci->port, tty); |
|
tty_port_tty_set(&dlci->port, NULL); |
|
return; |
|
} |
|
|
|
static void gsmtty_hangup(struct tty_struct *tty) |
|
{ |
|
struct gsm_dlci *dlci = tty->driver_data; |
|
if (dlci->state == DLCI_CLOSED) |
|
return; |
|
tty_port_hangup(&dlci->port); |
|
gsm_dlci_begin_close(dlci); |
|
} |
|
|
|
static int gsmtty_write(struct tty_struct *tty, const unsigned char *buf, |
|
int len) |
|
{ |
|
int sent; |
|
struct gsm_dlci *dlci = tty->driver_data; |
|
if (dlci->state == DLCI_CLOSED) |
|
return -EINVAL; |
|
/* Stuff the bytes into the fifo queue */ |
|
sent = kfifo_in_locked(&dlci->fifo, buf, len, &dlci->lock); |
|
/* Need to kick the channel */ |
|
gsm_dlci_data_kick(dlci); |
|
return sent; |
|
} |
|
|
|
static unsigned int gsmtty_write_room(struct tty_struct *tty) |
|
{ |
|
struct gsm_dlci *dlci = tty->driver_data; |
|
if (dlci->state == DLCI_CLOSED) |
|
return 0; |
|
return TX_SIZE - kfifo_len(&dlci->fifo); |
|
} |
|
|
|
static unsigned int gsmtty_chars_in_buffer(struct tty_struct *tty) |
|
{ |
|
struct gsm_dlci *dlci = tty->driver_data; |
|
if (dlci->state == DLCI_CLOSED) |
|
return 0; |
|
return kfifo_len(&dlci->fifo); |
|
} |
|
|
|
static void gsmtty_flush_buffer(struct tty_struct *tty) |
|
{ |
|
struct gsm_dlci *dlci = tty->driver_data; |
|
if (dlci->state == DLCI_CLOSED) |
|
return; |
|
/* Caution needed: If we implement reliable transport classes |
|
then the data being transmitted can't simply be junked once |
|
it has first hit the stack. Until then we can just blow it |
|
away */ |
|
kfifo_reset(&dlci->fifo); |
|
/* Need to unhook this DLCI from the transmit queue logic */ |
|
} |
|
|
|
static void gsmtty_wait_until_sent(struct tty_struct *tty, int timeout) |
|
{ |
|
/* The FIFO handles the queue so the kernel will do the right |
|
thing waiting on chars_in_buffer before calling us. No work |
|
to do here */ |
|
} |
|
|
|
static int gsmtty_tiocmget(struct tty_struct *tty) |
|
{ |
|
struct gsm_dlci *dlci = tty->driver_data; |
|
if (dlci->state == DLCI_CLOSED) |
|
return -EINVAL; |
|
return dlci->modem_rx; |
|
} |
|
|
|
static int gsmtty_tiocmset(struct tty_struct *tty, |
|
unsigned int set, unsigned int clear) |
|
{ |
|
struct gsm_dlci *dlci = tty->driver_data; |
|
unsigned int modem_tx = dlci->modem_tx; |
|
|
|
if (dlci->state == DLCI_CLOSED) |
|
return -EINVAL; |
|
modem_tx &= ~clear; |
|
modem_tx |= set; |
|
|
|
if (modem_tx != dlci->modem_tx) { |
|
dlci->modem_tx = modem_tx; |
|
return gsmtty_modem_update(dlci, 0); |
|
} |
|
return 0; |
|
} |
|
|
|
|
|
static int gsmtty_ioctl(struct tty_struct *tty, |
|
unsigned int cmd, unsigned long arg) |
|
{ |
|
struct gsm_dlci *dlci = tty->driver_data; |
|
struct gsm_netconfig nc; |
|
int index; |
|
|
|
if (dlci->state == DLCI_CLOSED) |
|
return -EINVAL; |
|
switch (cmd) { |
|
case GSMIOC_ENABLE_NET: |
|
if (copy_from_user(&nc, (void __user *)arg, sizeof(nc))) |
|
return -EFAULT; |
|
nc.if_name[IFNAMSIZ-1] = '\0'; |
|
/* return net interface index or error code */ |
|
mutex_lock(&dlci->mutex); |
|
index = gsm_create_network(dlci, &nc); |
|
mutex_unlock(&dlci->mutex); |
|
if (copy_to_user((void __user *)arg, &nc, sizeof(nc))) |
|
return -EFAULT; |
|
return index; |
|
case GSMIOC_DISABLE_NET: |
|
if (!capable(CAP_NET_ADMIN)) |
|
return -EPERM; |
|
mutex_lock(&dlci->mutex); |
|
gsm_destroy_network(dlci); |
|
mutex_unlock(&dlci->mutex); |
|
return 0; |
|
default: |
|
return -ENOIOCTLCMD; |
|
} |
|
} |
|
|
|
static void gsmtty_set_termios(struct tty_struct *tty, struct ktermios *old) |
|
{ |
|
struct gsm_dlci *dlci = tty->driver_data; |
|
if (dlci->state == DLCI_CLOSED) |
|
return; |
|
/* For the moment its fixed. In actual fact the speed information |
|
for the virtual channel can be propogated in both directions by |
|
the RPN control message. This however rapidly gets nasty as we |
|
then have to remap modem signals each way according to whether |
|
our virtual cable is null modem etc .. */ |
|
tty_termios_copy_hw(&tty->termios, old); |
|
} |
|
|
|
static void gsmtty_throttle(struct tty_struct *tty) |
|
{ |
|
struct gsm_dlci *dlci = tty->driver_data; |
|
if (dlci->state == DLCI_CLOSED) |
|
return; |
|
if (C_CRTSCTS(tty)) |
|
dlci->modem_tx &= ~TIOCM_DTR; |
|
dlci->throttled = true; |
|
/* Send an MSC with DTR cleared */ |
|
gsmtty_modem_update(dlci, 0); |
|
} |
|
|
|
static void gsmtty_unthrottle(struct tty_struct *tty) |
|
{ |
|
struct gsm_dlci *dlci = tty->driver_data; |
|
if (dlci->state == DLCI_CLOSED) |
|
return; |
|
if (C_CRTSCTS(tty)) |
|
dlci->modem_tx |= TIOCM_DTR; |
|
dlci->throttled = false; |
|
/* Send an MSC with DTR set */ |
|
gsmtty_modem_update(dlci, 0); |
|
} |
|
|
|
static int gsmtty_break_ctl(struct tty_struct *tty, int state) |
|
{ |
|
struct gsm_dlci *dlci = tty->driver_data; |
|
int encode = 0; /* Off */ |
|
if (dlci->state == DLCI_CLOSED) |
|
return -EINVAL; |
|
|
|
if (state == -1) /* "On indefinitely" - we can't encode this |
|
properly */ |
|
encode = 0x0F; |
|
else if (state > 0) { |
|
encode = state / 200; /* mS to encoding */ |
|
if (encode > 0x0F) |
|
encode = 0x0F; /* Best effort */ |
|
} |
|
return gsmtty_modem_update(dlci, encode); |
|
} |
|
|
|
static void gsmtty_cleanup(struct tty_struct *tty) |
|
{ |
|
struct gsm_dlci *dlci = tty->driver_data; |
|
struct gsm_mux *gsm = dlci->gsm; |
|
|
|
dlci_put(dlci); |
|
dlci_put(gsm->dlci[0]); |
|
mux_put(gsm); |
|
} |
|
|
|
/* Virtual ttys for the demux */ |
|
static const struct tty_operations gsmtty_ops = { |
|
.install = gsmtty_install, |
|
.open = gsmtty_open, |
|
.close = gsmtty_close, |
|
.write = gsmtty_write, |
|
.write_room = gsmtty_write_room, |
|
.chars_in_buffer = gsmtty_chars_in_buffer, |
|
.flush_buffer = gsmtty_flush_buffer, |
|
.ioctl = gsmtty_ioctl, |
|
.throttle = gsmtty_throttle, |
|
.unthrottle = gsmtty_unthrottle, |
|
.set_termios = gsmtty_set_termios, |
|
.hangup = gsmtty_hangup, |
|
.wait_until_sent = gsmtty_wait_until_sent, |
|
.tiocmget = gsmtty_tiocmget, |
|
.tiocmset = gsmtty_tiocmset, |
|
.break_ctl = gsmtty_break_ctl, |
|
.cleanup = gsmtty_cleanup, |
|
}; |
|
|
|
|
|
|
|
static int __init gsm_init(void) |
|
{ |
|
/* Fill in our line protocol discipline, and register it */ |
|
int status = tty_register_ldisc(&tty_ldisc_packet); |
|
if (status != 0) { |
|
pr_err("n_gsm: can't register line discipline (err = %d)\n", |
|
status); |
|
return status; |
|
} |
|
|
|
gsm_tty_driver = alloc_tty_driver(256); |
|
if (!gsm_tty_driver) { |
|
pr_err("gsm_init: tty allocation failed.\n"); |
|
status = -ENOMEM; |
|
goto err_unreg_ldisc; |
|
} |
|
gsm_tty_driver->driver_name = "gsmtty"; |
|
gsm_tty_driver->name = "gsmtty"; |
|
gsm_tty_driver->major = 0; /* Dynamic */ |
|
gsm_tty_driver->minor_start = 0; |
|
gsm_tty_driver->type = TTY_DRIVER_TYPE_SERIAL; |
|
gsm_tty_driver->subtype = SERIAL_TYPE_NORMAL; |
|
gsm_tty_driver->flags = TTY_DRIVER_REAL_RAW | TTY_DRIVER_DYNAMIC_DEV |
|
| TTY_DRIVER_HARDWARE_BREAK; |
|
gsm_tty_driver->init_termios = tty_std_termios; |
|
/* Fixme */ |
|
gsm_tty_driver->init_termios.c_lflag &= ~ECHO; |
|
tty_set_operations(gsm_tty_driver, &gsmtty_ops); |
|
|
|
if (tty_register_driver(gsm_tty_driver)) { |
|
pr_err("gsm_init: tty registration failed.\n"); |
|
status = -EBUSY; |
|
goto err_put_driver; |
|
} |
|
pr_debug("gsm_init: loaded as %d,%d.\n", |
|
gsm_tty_driver->major, gsm_tty_driver->minor_start); |
|
return 0; |
|
err_put_driver: |
|
put_tty_driver(gsm_tty_driver); |
|
err_unreg_ldisc: |
|
tty_unregister_ldisc(&tty_ldisc_packet); |
|
return status; |
|
} |
|
|
|
static void __exit gsm_exit(void) |
|
{ |
|
tty_unregister_ldisc(&tty_ldisc_packet); |
|
tty_unregister_driver(gsm_tty_driver); |
|
put_tty_driver(gsm_tty_driver); |
|
} |
|
|
|
module_init(gsm_init); |
|
module_exit(gsm_exit); |
|
|
|
|
|
MODULE_LICENSE("GPL"); |
|
MODULE_ALIAS_LDISC(N_GSM0710);
|
|
|