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1505 lines
36 KiB
1505 lines
36 KiB
// SPDX-License-Identifier: GPL-2.0+ |
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/* |
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* u_serial.c - utilities for USB gadget "serial port"/TTY support |
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* |
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* Copyright (C) 2003 Al Borchers ([email protected]) |
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* Copyright (C) 2008 David Brownell |
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* Copyright (C) 2008 by Nokia Corporation |
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* |
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* This code also borrows from usbserial.c, which is |
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* Copyright (C) 1999 - 2002 Greg Kroah-Hartman ([email protected]) |
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* Copyright (C) 2000 Peter Berger ([email protected]) |
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* Copyright (C) 2000 Al Borchers ([email protected]) |
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*/ |
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|
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/* #define VERBOSE_DEBUG */ |
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|
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#include <linux/kernel.h> |
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#include <linux/sched.h> |
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#include <linux/device.h> |
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#include <linux/delay.h> |
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#include <linux/tty.h> |
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#include <linux/tty_flip.h> |
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#include <linux/slab.h> |
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#include <linux/export.h> |
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#include <linux/module.h> |
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#include <linux/console.h> |
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#include <linux/kthread.h> |
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#include <linux/workqueue.h> |
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#include <linux/kfifo.h> |
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|
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#include "u_serial.h" |
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|
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/* |
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* This component encapsulates the TTY layer glue needed to provide basic |
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* "serial port" functionality through the USB gadget stack. Each such |
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* port is exposed through a /dev/ttyGS* node. |
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* |
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* After this module has been loaded, the individual TTY port can be requested |
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* (gserial_alloc_line()) and it will stay available until they are removed |
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* (gserial_free_line()). Each one may be connected to a USB function |
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* (gserial_connect), or disconnected (with gserial_disconnect) when the USB |
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* host issues a config change event. Data can only flow when the port is |
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* connected to the host. |
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* |
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* A given TTY port can be made available in multiple configurations. |
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* For example, each one might expose a ttyGS0 node which provides a |
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* login application. In one case that might use CDC ACM interface 0, |
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* while another configuration might use interface 3 for that. The |
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* work to handle that (including descriptor management) is not part |
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* of this component. |
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* |
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* Configurations may expose more than one TTY port. For example, if |
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* ttyGS0 provides login service, then ttyGS1 might provide dialer access |
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* for a telephone or fax link. And ttyGS2 might be something that just |
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* needs a simple byte stream interface for some messaging protocol that |
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* is managed in userspace ... OBEX, PTP, and MTP have been mentioned. |
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* |
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* |
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* gserial is the lifecycle interface, used by USB functions |
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* gs_port is the I/O nexus, used by the tty driver |
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* tty_struct links to the tty/filesystem framework |
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* |
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* gserial <---> gs_port ... links will be null when the USB link is |
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* inactive; managed by gserial_{connect,disconnect}(). each gserial |
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* instance can wrap its own USB control protocol. |
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* gserial->ioport == usb_ep->driver_data ... gs_port |
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* gs_port->port_usb ... gserial |
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* |
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* gs_port <---> tty_struct ... links will be null when the TTY file |
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* isn't opened; managed by gs_open()/gs_close() |
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* gserial->port_tty ... tty_struct |
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* tty_struct->driver_data ... gserial |
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*/ |
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|
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/* RX and TX queues can buffer QUEUE_SIZE packets before they hit the |
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* next layer of buffering. For TX that's a circular buffer; for RX |
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* consider it a NOP. A third layer is provided by the TTY code. |
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*/ |
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#define QUEUE_SIZE 16 |
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#define WRITE_BUF_SIZE 8192 /* TX only */ |
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#define GS_CONSOLE_BUF_SIZE 8192 |
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|
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/* console info */ |
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struct gs_console { |
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struct console console; |
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struct work_struct work; |
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spinlock_t lock; |
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struct usb_request *req; |
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struct kfifo buf; |
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size_t missed; |
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}; |
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|
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/* |
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* The port structure holds info for each port, one for each minor number |
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* (and thus for each /dev/ node). |
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*/ |
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struct gs_port { |
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struct tty_port port; |
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spinlock_t port_lock; /* guard port_* access */ |
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|
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struct gserial *port_usb; |
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#ifdef CONFIG_U_SERIAL_CONSOLE |
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struct gs_console *console; |
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#endif |
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u8 port_num; |
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struct list_head read_pool; |
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int read_started; |
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int read_allocated; |
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struct list_head read_queue; |
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unsigned n_read; |
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struct delayed_work push; |
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struct list_head write_pool; |
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int write_started; |
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int write_allocated; |
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struct kfifo port_write_buf; |
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wait_queue_head_t drain_wait; /* wait while writes drain */ |
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bool write_busy; |
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wait_queue_head_t close_wait; |
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bool suspended; /* port suspended */ |
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bool start_delayed; /* delay start when suspended */ |
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|
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/* REVISIT this state ... */ |
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struct usb_cdc_line_coding port_line_coding; /* 8-N-1 etc */ |
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}; |
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|
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static struct portmaster { |
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struct mutex lock; /* protect open/close */ |
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struct gs_port *port; |
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} ports[MAX_U_SERIAL_PORTS]; |
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#define GS_CLOSE_TIMEOUT 15 /* seconds */ |
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#ifdef VERBOSE_DEBUG |
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#ifndef pr_vdebug |
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#define pr_vdebug(fmt, arg...) \ |
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pr_debug(fmt, ##arg) |
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#endif /* pr_vdebug */ |
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#else |
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#ifndef pr_vdebug |
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#define pr_vdebug(fmt, arg...) \ |
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({ if (0) pr_debug(fmt, ##arg); }) |
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#endif /* pr_vdebug */ |
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#endif |
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/*-------------------------------------------------------------------------*/ |
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/* I/O glue between TTY (upper) and USB function (lower) driver layers */ |
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|
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/* |
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* gs_alloc_req |
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* |
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* Allocate a usb_request and its buffer. Returns a pointer to the |
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* usb_request or NULL if there is an error. |
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*/ |
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struct usb_request * |
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gs_alloc_req(struct usb_ep *ep, unsigned len, gfp_t kmalloc_flags) |
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{ |
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struct usb_request *req; |
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|
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req = usb_ep_alloc_request(ep, kmalloc_flags); |
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|
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if (req != NULL) { |
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req->length = len; |
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req->buf = kmalloc(len, kmalloc_flags); |
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if (req->buf == NULL) { |
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usb_ep_free_request(ep, req); |
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return NULL; |
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} |
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} |
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return req; |
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} |
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EXPORT_SYMBOL_GPL(gs_alloc_req); |
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/* |
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* gs_free_req |
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* |
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* Free a usb_request and its buffer. |
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*/ |
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void gs_free_req(struct usb_ep *ep, struct usb_request *req) |
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{ |
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kfree(req->buf); |
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usb_ep_free_request(ep, req); |
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} |
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EXPORT_SYMBOL_GPL(gs_free_req); |
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|
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/* |
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* gs_send_packet |
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* |
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* If there is data to send, a packet is built in the given |
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* buffer and the size is returned. If there is no data to |
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* send, 0 is returned. |
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* |
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* Called with port_lock held. |
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*/ |
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static unsigned |
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gs_send_packet(struct gs_port *port, char *packet, unsigned size) |
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{ |
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unsigned len; |
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|
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len = kfifo_len(&port->port_write_buf); |
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if (len < size) |
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size = len; |
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if (size != 0) |
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size = kfifo_out(&port->port_write_buf, packet, size); |
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return size; |
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} |
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/* |
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* gs_start_tx |
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* |
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* This function finds available write requests, calls |
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* gs_send_packet to fill these packets with data, and |
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* continues until either there are no more write requests |
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* available or no more data to send. This function is |
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* run whenever data arrives or write requests are available. |
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* |
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* Context: caller owns port_lock; port_usb is non-null. |
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*/ |
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static int gs_start_tx(struct gs_port *port) |
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/* |
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__releases(&port->port_lock) |
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__acquires(&port->port_lock) |
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*/ |
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{ |
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struct list_head *pool = &port->write_pool; |
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struct usb_ep *in; |
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int status = 0; |
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bool do_tty_wake = false; |
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|
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if (!port->port_usb) |
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return status; |
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in = port->port_usb->in; |
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while (!port->write_busy && !list_empty(pool)) { |
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struct usb_request *req; |
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int len; |
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if (port->write_started >= QUEUE_SIZE) |
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break; |
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req = list_entry(pool->next, struct usb_request, list); |
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len = gs_send_packet(port, req->buf, in->maxpacket); |
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if (len == 0) { |
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wake_up_interruptible(&port->drain_wait); |
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break; |
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} |
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do_tty_wake = true; |
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|
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req->length = len; |
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list_del(&req->list); |
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req->zero = kfifo_is_empty(&port->port_write_buf); |
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pr_vdebug("ttyGS%d: tx len=%d, %3ph ...\n", port->port_num, len, req->buf); |
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|
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/* Drop lock while we call out of driver; completions |
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* could be issued while we do so. Disconnection may |
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* happen too; maybe immediately before we queue this! |
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* |
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* NOTE that we may keep sending data for a while after |
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* the TTY closed (dev->ioport->port_tty is NULL). |
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*/ |
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port->write_busy = true; |
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spin_unlock(&port->port_lock); |
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status = usb_ep_queue(in, req, GFP_ATOMIC); |
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spin_lock(&port->port_lock); |
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port->write_busy = false; |
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|
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if (status) { |
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pr_debug("%s: %s %s err %d\n", |
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__func__, "queue", in->name, status); |
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list_add(&req->list, pool); |
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break; |
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} |
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port->write_started++; |
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|
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/* abort immediately after disconnect */ |
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if (!port->port_usb) |
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break; |
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} |
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if (do_tty_wake && port->port.tty) |
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tty_wakeup(port->port.tty); |
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return status; |
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} |
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|
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/* |
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* Context: caller owns port_lock, and port_usb is set |
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*/ |
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static unsigned gs_start_rx(struct gs_port *port) |
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/* |
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__releases(&port->port_lock) |
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__acquires(&port->port_lock) |
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*/ |
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{ |
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struct list_head *pool = &port->read_pool; |
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struct usb_ep *out = port->port_usb->out; |
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while (!list_empty(pool)) { |
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struct usb_request *req; |
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int status; |
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struct tty_struct *tty; |
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|
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/* no more rx if closed */ |
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tty = port->port.tty; |
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if (!tty) |
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break; |
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if (port->read_started >= QUEUE_SIZE) |
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break; |
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req = list_entry(pool->next, struct usb_request, list); |
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list_del(&req->list); |
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req->length = out->maxpacket; |
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|
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/* drop lock while we call out; the controller driver |
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* may need to call us back (e.g. for disconnect) |
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*/ |
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spin_unlock(&port->port_lock); |
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status = usb_ep_queue(out, req, GFP_ATOMIC); |
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spin_lock(&port->port_lock); |
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if (status) { |
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pr_debug("%s: %s %s err %d\n", |
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__func__, "queue", out->name, status); |
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list_add(&req->list, pool); |
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break; |
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} |
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port->read_started++; |
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|
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/* abort immediately after disconnect */ |
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if (!port->port_usb) |
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break; |
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} |
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return port->read_started; |
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} |
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|
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/* |
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* RX work takes data out of the RX queue and hands it up to the TTY |
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* layer until it refuses to take any more data (or is throttled back). |
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* Then it issues reads for any further data. |
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* |
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* If the RX queue becomes full enough that no usb_request is queued, |
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* the OUT endpoint may begin NAKing as soon as its FIFO fills up. |
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* So QUEUE_SIZE packets plus however many the FIFO holds (usually two) |
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* can be buffered before the TTY layer's buffers (currently 64 KB). |
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*/ |
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static void gs_rx_push(struct work_struct *work) |
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{ |
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struct delayed_work *w = to_delayed_work(work); |
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struct gs_port *port = container_of(w, struct gs_port, push); |
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struct tty_struct *tty; |
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struct list_head *queue = &port->read_queue; |
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bool disconnect = false; |
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bool do_push = false; |
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|
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/* hand any queued data to the tty */ |
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spin_lock_irq(&port->port_lock); |
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tty = port->port.tty; |
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while (!list_empty(queue)) { |
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struct usb_request *req; |
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|
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req = list_first_entry(queue, struct usb_request, list); |
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|
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/* leave data queued if tty was rx throttled */ |
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if (tty && tty_throttled(tty)) |
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break; |
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|
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switch (req->status) { |
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case -ESHUTDOWN: |
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disconnect = true; |
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pr_vdebug("ttyGS%d: shutdown\n", port->port_num); |
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break; |
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|
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default: |
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/* presumably a transient fault */ |
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pr_warn("ttyGS%d: unexpected RX status %d\n", |
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port->port_num, req->status); |
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fallthrough; |
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case 0: |
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/* normal completion */ |
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break; |
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} |
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|
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/* push data to (open) tty */ |
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if (req->actual && tty) { |
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char *packet = req->buf; |
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unsigned size = req->actual; |
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unsigned n; |
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int count; |
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|
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/* we may have pushed part of this packet already... */ |
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n = port->n_read; |
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if (n) { |
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packet += n; |
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size -= n; |
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} |
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|
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count = tty_insert_flip_string(&port->port, packet, |
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size); |
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if (count) |
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do_push = true; |
|
if (count != size) { |
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/* stop pushing; TTY layer can't handle more */ |
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port->n_read += count; |
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pr_vdebug("ttyGS%d: rx block %d/%d\n", |
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port->port_num, count, req->actual); |
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break; |
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} |
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port->n_read = 0; |
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} |
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|
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list_move(&req->list, &port->read_pool); |
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port->read_started--; |
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} |
|
|
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/* Push from tty to ldisc; this is handled by a workqueue, |
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* so we won't get callbacks and can hold port_lock |
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*/ |
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if (do_push) |
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tty_flip_buffer_push(&port->port); |
|
|
|
|
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/* We want our data queue to become empty ASAP, keeping data |
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* in the tty and ldisc (not here). If we couldn't push any |
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* this time around, RX may be starved, so wait until next jiffy. |
|
* |
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* We may leave non-empty queue only when there is a tty, and |
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* either it is throttled or there is no more room in flip buffer. |
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*/ |
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if (!list_empty(queue) && !tty_throttled(tty)) |
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schedule_delayed_work(&port->push, 1); |
|
|
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/* If we're still connected, refill the USB RX queue. */ |
|
if (!disconnect && port->port_usb) |
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gs_start_rx(port); |
|
|
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spin_unlock_irq(&port->port_lock); |
|
} |
|
|
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static void gs_read_complete(struct usb_ep *ep, struct usb_request *req) |
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{ |
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struct gs_port *port = ep->driver_data; |
|
|
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/* Queue all received data until the tty layer is ready for it. */ |
|
spin_lock(&port->port_lock); |
|
list_add_tail(&req->list, &port->read_queue); |
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schedule_delayed_work(&port->push, 0); |
|
spin_unlock(&port->port_lock); |
|
} |
|
|
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static void gs_write_complete(struct usb_ep *ep, struct usb_request *req) |
|
{ |
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struct gs_port *port = ep->driver_data; |
|
|
|
spin_lock(&port->port_lock); |
|
list_add(&req->list, &port->write_pool); |
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port->write_started--; |
|
|
|
switch (req->status) { |
|
default: |
|
/* presumably a transient fault */ |
|
pr_warn("%s: unexpected %s status %d\n", |
|
__func__, ep->name, req->status); |
|
fallthrough; |
|
case 0: |
|
/* normal completion */ |
|
gs_start_tx(port); |
|
break; |
|
|
|
case -ESHUTDOWN: |
|
/* disconnect */ |
|
pr_vdebug("%s: %s shutdown\n", __func__, ep->name); |
|
break; |
|
} |
|
|
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spin_unlock(&port->port_lock); |
|
} |
|
|
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static void gs_free_requests(struct usb_ep *ep, struct list_head *head, |
|
int *allocated) |
|
{ |
|
struct usb_request *req; |
|
|
|
while (!list_empty(head)) { |
|
req = list_entry(head->next, struct usb_request, list); |
|
list_del(&req->list); |
|
gs_free_req(ep, req); |
|
if (allocated) |
|
(*allocated)--; |
|
} |
|
} |
|
|
|
static int gs_alloc_requests(struct usb_ep *ep, struct list_head *head, |
|
void (*fn)(struct usb_ep *, struct usb_request *), |
|
int *allocated) |
|
{ |
|
int i; |
|
struct usb_request *req; |
|
int n = allocated ? QUEUE_SIZE - *allocated : QUEUE_SIZE; |
|
|
|
/* Pre-allocate up to QUEUE_SIZE transfers, but if we can't |
|
* do quite that many this time, don't fail ... we just won't |
|
* be as speedy as we might otherwise be. |
|
*/ |
|
for (i = 0; i < n; i++) { |
|
req = gs_alloc_req(ep, ep->maxpacket, GFP_ATOMIC); |
|
if (!req) |
|
return list_empty(head) ? -ENOMEM : 0; |
|
req->complete = fn; |
|
list_add_tail(&req->list, head); |
|
if (allocated) |
|
(*allocated)++; |
|
} |
|
return 0; |
|
} |
|
|
|
/** |
|
* gs_start_io - start USB I/O streams |
|
* @port: port to use |
|
* Context: holding port_lock; port_tty and port_usb are non-null |
|
* |
|
* We only start I/O when something is connected to both sides of |
|
* this port. If nothing is listening on the host side, we may |
|
* be pointlessly filling up our TX buffers and FIFO. |
|
*/ |
|
static int gs_start_io(struct gs_port *port) |
|
{ |
|
struct list_head *head = &port->read_pool; |
|
struct usb_ep *ep = port->port_usb->out; |
|
int status; |
|
unsigned started; |
|
|
|
/* Allocate RX and TX I/O buffers. We can't easily do this much |
|
* earlier (with GFP_KERNEL) because the requests are coupled to |
|
* endpoints, as are the packet sizes we'll be using. Different |
|
* configurations may use different endpoints with a given port; |
|
* and high speed vs full speed changes packet sizes too. |
|
*/ |
|
status = gs_alloc_requests(ep, head, gs_read_complete, |
|
&port->read_allocated); |
|
if (status) |
|
return status; |
|
|
|
status = gs_alloc_requests(port->port_usb->in, &port->write_pool, |
|
gs_write_complete, &port->write_allocated); |
|
if (status) { |
|
gs_free_requests(ep, head, &port->read_allocated); |
|
return status; |
|
} |
|
|
|
/* queue read requests */ |
|
port->n_read = 0; |
|
started = gs_start_rx(port); |
|
|
|
if (started) { |
|
gs_start_tx(port); |
|
/* Unblock any pending writes into our circular buffer, in case |
|
* we didn't in gs_start_tx() */ |
|
tty_wakeup(port->port.tty); |
|
} else { |
|
gs_free_requests(ep, head, &port->read_allocated); |
|
gs_free_requests(port->port_usb->in, &port->write_pool, |
|
&port->write_allocated); |
|
status = -EIO; |
|
} |
|
|
|
return status; |
|
} |
|
|
|
/*-------------------------------------------------------------------------*/ |
|
|
|
/* TTY Driver */ |
|
|
|
/* |
|
* gs_open sets up the link between a gs_port and its associated TTY. |
|
* That link is broken *only* by TTY close(), and all driver methods |
|
* know that. |
|
*/ |
|
static int gs_open(struct tty_struct *tty, struct file *file) |
|
{ |
|
int port_num = tty->index; |
|
struct gs_port *port; |
|
int status = 0; |
|
|
|
mutex_lock(&ports[port_num].lock); |
|
port = ports[port_num].port; |
|
if (!port) { |
|
status = -ENODEV; |
|
goto out; |
|
} |
|
|
|
spin_lock_irq(&port->port_lock); |
|
|
|
/* allocate circular buffer on first open */ |
|
if (!kfifo_initialized(&port->port_write_buf)) { |
|
|
|
spin_unlock_irq(&port->port_lock); |
|
|
|
/* |
|
* portmaster's mutex still protects from simultaneous open(), |
|
* and close() can't happen, yet. |
|
*/ |
|
|
|
status = kfifo_alloc(&port->port_write_buf, |
|
WRITE_BUF_SIZE, GFP_KERNEL); |
|
if (status) { |
|
pr_debug("gs_open: ttyGS%d (%p,%p) no buffer\n", |
|
port_num, tty, file); |
|
goto out; |
|
} |
|
|
|
spin_lock_irq(&port->port_lock); |
|
} |
|
|
|
/* already open? Great. */ |
|
if (port->port.count++) |
|
goto exit_unlock_port; |
|
|
|
tty->driver_data = port; |
|
port->port.tty = tty; |
|
|
|
/* if connected, start the I/O stream */ |
|
if (port->port_usb) { |
|
/* if port is suspended, wait resume to start I/0 stream */ |
|
if (!port->suspended) { |
|
struct gserial *gser = port->port_usb; |
|
|
|
pr_debug("gs_open: start ttyGS%d\n", port->port_num); |
|
gs_start_io(port); |
|
|
|
if (gser->connect) |
|
gser->connect(gser); |
|
} else { |
|
pr_debug("delay start of ttyGS%d\n", port->port_num); |
|
port->start_delayed = true; |
|
} |
|
} |
|
|
|
pr_debug("gs_open: ttyGS%d (%p,%p)\n", port->port_num, tty, file); |
|
|
|
exit_unlock_port: |
|
spin_unlock_irq(&port->port_lock); |
|
out: |
|
mutex_unlock(&ports[port_num].lock); |
|
return status; |
|
} |
|
|
|
static int gs_close_flush_done(struct gs_port *p) |
|
{ |
|
int cond; |
|
|
|
/* return true on disconnect or empty buffer or if raced with open() */ |
|
spin_lock_irq(&p->port_lock); |
|
cond = p->port_usb == NULL || !kfifo_len(&p->port_write_buf) || |
|
p->port.count > 1; |
|
spin_unlock_irq(&p->port_lock); |
|
|
|
return cond; |
|
} |
|
|
|
static void gs_close(struct tty_struct *tty, struct file *file) |
|
{ |
|
struct gs_port *port = tty->driver_data; |
|
struct gserial *gser; |
|
|
|
spin_lock_irq(&port->port_lock); |
|
|
|
if (port->port.count != 1) { |
|
raced_with_open: |
|
if (port->port.count == 0) |
|
WARN_ON(1); |
|
else |
|
--port->port.count; |
|
goto exit; |
|
} |
|
|
|
pr_debug("gs_close: ttyGS%d (%p,%p) ...\n", port->port_num, tty, file); |
|
|
|
gser = port->port_usb; |
|
if (gser && !port->suspended && gser->disconnect) |
|
gser->disconnect(gser); |
|
|
|
/* wait for circular write buffer to drain, disconnect, or at |
|
* most GS_CLOSE_TIMEOUT seconds; then discard the rest |
|
*/ |
|
if (kfifo_len(&port->port_write_buf) > 0 && gser) { |
|
spin_unlock_irq(&port->port_lock); |
|
wait_event_interruptible_timeout(port->drain_wait, |
|
gs_close_flush_done(port), |
|
GS_CLOSE_TIMEOUT * HZ); |
|
spin_lock_irq(&port->port_lock); |
|
|
|
if (port->port.count != 1) |
|
goto raced_with_open; |
|
|
|
gser = port->port_usb; |
|
} |
|
|
|
/* Iff we're disconnected, there can be no I/O in flight so it's |
|
* ok to free the circular buffer; else just scrub it. And don't |
|
* let the push async work fire again until we're re-opened. |
|
*/ |
|
if (gser == NULL) |
|
kfifo_free(&port->port_write_buf); |
|
else |
|
kfifo_reset(&port->port_write_buf); |
|
|
|
port->start_delayed = false; |
|
port->port.count = 0; |
|
port->port.tty = NULL; |
|
|
|
pr_debug("gs_close: ttyGS%d (%p,%p) done!\n", |
|
port->port_num, tty, file); |
|
|
|
wake_up(&port->close_wait); |
|
exit: |
|
spin_unlock_irq(&port->port_lock); |
|
} |
|
|
|
static int gs_write(struct tty_struct *tty, const unsigned char *buf, int count) |
|
{ |
|
struct gs_port *port = tty->driver_data; |
|
unsigned long flags; |
|
|
|
pr_vdebug("gs_write: ttyGS%d (%p) writing %d bytes\n", |
|
port->port_num, tty, count); |
|
|
|
spin_lock_irqsave(&port->port_lock, flags); |
|
if (count) |
|
count = kfifo_in(&port->port_write_buf, buf, count); |
|
/* treat count == 0 as flush_chars() */ |
|
if (port->port_usb) |
|
gs_start_tx(port); |
|
spin_unlock_irqrestore(&port->port_lock, flags); |
|
|
|
return count; |
|
} |
|
|
|
static int gs_put_char(struct tty_struct *tty, unsigned char ch) |
|
{ |
|
struct gs_port *port = tty->driver_data; |
|
unsigned long flags; |
|
int status; |
|
|
|
pr_vdebug("gs_put_char: (%d,%p) char=0x%x, called from %ps\n", |
|
port->port_num, tty, ch, __builtin_return_address(0)); |
|
|
|
spin_lock_irqsave(&port->port_lock, flags); |
|
status = kfifo_put(&port->port_write_buf, ch); |
|
spin_unlock_irqrestore(&port->port_lock, flags); |
|
|
|
return status; |
|
} |
|
|
|
static void gs_flush_chars(struct tty_struct *tty) |
|
{ |
|
struct gs_port *port = tty->driver_data; |
|
unsigned long flags; |
|
|
|
pr_vdebug("gs_flush_chars: (%d,%p)\n", port->port_num, tty); |
|
|
|
spin_lock_irqsave(&port->port_lock, flags); |
|
if (port->port_usb) |
|
gs_start_tx(port); |
|
spin_unlock_irqrestore(&port->port_lock, flags); |
|
} |
|
|
|
static int gs_write_room(struct tty_struct *tty) |
|
{ |
|
struct gs_port *port = tty->driver_data; |
|
unsigned long flags; |
|
int room = 0; |
|
|
|
spin_lock_irqsave(&port->port_lock, flags); |
|
if (port->port_usb) |
|
room = kfifo_avail(&port->port_write_buf); |
|
spin_unlock_irqrestore(&port->port_lock, flags); |
|
|
|
pr_vdebug("gs_write_room: (%d,%p) room=%d\n", |
|
port->port_num, tty, room); |
|
|
|
return room; |
|
} |
|
|
|
static int gs_chars_in_buffer(struct tty_struct *tty) |
|
{ |
|
struct gs_port *port = tty->driver_data; |
|
unsigned long flags; |
|
int chars = 0; |
|
|
|
spin_lock_irqsave(&port->port_lock, flags); |
|
chars = kfifo_len(&port->port_write_buf); |
|
spin_unlock_irqrestore(&port->port_lock, flags); |
|
|
|
pr_vdebug("gs_chars_in_buffer: (%d,%p) chars=%d\n", |
|
port->port_num, tty, chars); |
|
|
|
return chars; |
|
} |
|
|
|
/* undo side effects of setting TTY_THROTTLED */ |
|
static void gs_unthrottle(struct tty_struct *tty) |
|
{ |
|
struct gs_port *port = tty->driver_data; |
|
unsigned long flags; |
|
|
|
spin_lock_irqsave(&port->port_lock, flags); |
|
if (port->port_usb) { |
|
/* Kickstart read queue processing. We don't do xon/xoff, |
|
* rts/cts, or other handshaking with the host, but if the |
|
* read queue backs up enough we'll be NAKing OUT packets. |
|
*/ |
|
pr_vdebug("ttyGS%d: unthrottle\n", port->port_num); |
|
schedule_delayed_work(&port->push, 0); |
|
} |
|
spin_unlock_irqrestore(&port->port_lock, flags); |
|
} |
|
|
|
static int gs_break_ctl(struct tty_struct *tty, int duration) |
|
{ |
|
struct gs_port *port = tty->driver_data; |
|
int status = 0; |
|
struct gserial *gser; |
|
|
|
pr_vdebug("gs_break_ctl: ttyGS%d, send break (%d) \n", |
|
port->port_num, duration); |
|
|
|
spin_lock_irq(&port->port_lock); |
|
gser = port->port_usb; |
|
if (gser && gser->send_break) |
|
status = gser->send_break(gser, duration); |
|
spin_unlock_irq(&port->port_lock); |
|
|
|
return status; |
|
} |
|
|
|
static const struct tty_operations gs_tty_ops = { |
|
.open = gs_open, |
|
.close = gs_close, |
|
.write = gs_write, |
|
.put_char = gs_put_char, |
|
.flush_chars = gs_flush_chars, |
|
.write_room = gs_write_room, |
|
.chars_in_buffer = gs_chars_in_buffer, |
|
.unthrottle = gs_unthrottle, |
|
.break_ctl = gs_break_ctl, |
|
}; |
|
|
|
/*-------------------------------------------------------------------------*/ |
|
|
|
static struct tty_driver *gs_tty_driver; |
|
|
|
#ifdef CONFIG_U_SERIAL_CONSOLE |
|
|
|
static void gs_console_complete_out(struct usb_ep *ep, struct usb_request *req) |
|
{ |
|
struct gs_console *cons = req->context; |
|
|
|
switch (req->status) { |
|
default: |
|
pr_warn("%s: unexpected %s status %d\n", |
|
__func__, ep->name, req->status); |
|
fallthrough; |
|
case 0: |
|
/* normal completion */ |
|
spin_lock(&cons->lock); |
|
req->length = 0; |
|
schedule_work(&cons->work); |
|
spin_unlock(&cons->lock); |
|
break; |
|
case -ECONNRESET: |
|
case -ESHUTDOWN: |
|
/* disconnect */ |
|
pr_vdebug("%s: %s shutdown\n", __func__, ep->name); |
|
break; |
|
} |
|
} |
|
|
|
static void __gs_console_push(struct gs_console *cons) |
|
{ |
|
struct usb_request *req = cons->req; |
|
struct usb_ep *ep; |
|
size_t size; |
|
|
|
if (!req) |
|
return; /* disconnected */ |
|
|
|
if (req->length) |
|
return; /* busy */ |
|
|
|
ep = cons->console.data; |
|
size = kfifo_out(&cons->buf, req->buf, ep->maxpacket); |
|
if (!size) |
|
return; |
|
|
|
if (cons->missed && ep->maxpacket >= 64) { |
|
char buf[64]; |
|
size_t len; |
|
|
|
len = sprintf(buf, "\n[missed %zu bytes]\n", cons->missed); |
|
kfifo_in(&cons->buf, buf, len); |
|
cons->missed = 0; |
|
} |
|
|
|
req->length = size; |
|
if (usb_ep_queue(ep, req, GFP_ATOMIC)) |
|
req->length = 0; |
|
} |
|
|
|
static void gs_console_work(struct work_struct *work) |
|
{ |
|
struct gs_console *cons = container_of(work, struct gs_console, work); |
|
|
|
spin_lock_irq(&cons->lock); |
|
|
|
__gs_console_push(cons); |
|
|
|
spin_unlock_irq(&cons->lock); |
|
} |
|
|
|
static void gs_console_write(struct console *co, |
|
const char *buf, unsigned count) |
|
{ |
|
struct gs_console *cons = container_of(co, struct gs_console, console); |
|
unsigned long flags; |
|
size_t n; |
|
|
|
spin_lock_irqsave(&cons->lock, flags); |
|
|
|
n = kfifo_in(&cons->buf, buf, count); |
|
if (n < count) |
|
cons->missed += count - n; |
|
|
|
if (cons->req && !cons->req->length) |
|
schedule_work(&cons->work); |
|
|
|
spin_unlock_irqrestore(&cons->lock, flags); |
|
} |
|
|
|
static struct tty_driver *gs_console_device(struct console *co, int *index) |
|
{ |
|
*index = co->index; |
|
return gs_tty_driver; |
|
} |
|
|
|
static int gs_console_connect(struct gs_port *port) |
|
{ |
|
struct gs_console *cons = port->console; |
|
struct usb_request *req; |
|
struct usb_ep *ep; |
|
|
|
if (!cons) |
|
return 0; |
|
|
|
ep = port->port_usb->in; |
|
req = gs_alloc_req(ep, ep->maxpacket, GFP_ATOMIC); |
|
if (!req) |
|
return -ENOMEM; |
|
req->complete = gs_console_complete_out; |
|
req->context = cons; |
|
req->length = 0; |
|
|
|
spin_lock(&cons->lock); |
|
cons->req = req; |
|
cons->console.data = ep; |
|
spin_unlock(&cons->lock); |
|
|
|
pr_debug("ttyGS%d: console connected!\n", port->port_num); |
|
|
|
schedule_work(&cons->work); |
|
|
|
return 0; |
|
} |
|
|
|
static void gs_console_disconnect(struct gs_port *port) |
|
{ |
|
struct gs_console *cons = port->console; |
|
struct usb_request *req; |
|
struct usb_ep *ep; |
|
|
|
if (!cons) |
|
return; |
|
|
|
spin_lock(&cons->lock); |
|
|
|
req = cons->req; |
|
ep = cons->console.data; |
|
cons->req = NULL; |
|
|
|
spin_unlock(&cons->lock); |
|
|
|
if (!req) |
|
return; |
|
|
|
usb_ep_dequeue(ep, req); |
|
gs_free_req(ep, req); |
|
} |
|
|
|
static int gs_console_init(struct gs_port *port) |
|
{ |
|
struct gs_console *cons; |
|
int err; |
|
|
|
if (port->console) |
|
return 0; |
|
|
|
cons = kzalloc(sizeof(*port->console), GFP_KERNEL); |
|
if (!cons) |
|
return -ENOMEM; |
|
|
|
strcpy(cons->console.name, "ttyGS"); |
|
cons->console.write = gs_console_write; |
|
cons->console.device = gs_console_device; |
|
cons->console.flags = CON_PRINTBUFFER; |
|
cons->console.index = port->port_num; |
|
|
|
INIT_WORK(&cons->work, gs_console_work); |
|
spin_lock_init(&cons->lock); |
|
|
|
err = kfifo_alloc(&cons->buf, GS_CONSOLE_BUF_SIZE, GFP_KERNEL); |
|
if (err) { |
|
pr_err("ttyGS%d: allocate console buffer failed\n", port->port_num); |
|
kfree(cons); |
|
return err; |
|
} |
|
|
|
port->console = cons; |
|
register_console(&cons->console); |
|
|
|
spin_lock_irq(&port->port_lock); |
|
if (port->port_usb) |
|
gs_console_connect(port); |
|
spin_unlock_irq(&port->port_lock); |
|
|
|
return 0; |
|
} |
|
|
|
static void gs_console_exit(struct gs_port *port) |
|
{ |
|
struct gs_console *cons = port->console; |
|
|
|
if (!cons) |
|
return; |
|
|
|
unregister_console(&cons->console); |
|
|
|
spin_lock_irq(&port->port_lock); |
|
if (cons->req) |
|
gs_console_disconnect(port); |
|
spin_unlock_irq(&port->port_lock); |
|
|
|
cancel_work_sync(&cons->work); |
|
kfifo_free(&cons->buf); |
|
kfree(cons); |
|
port->console = NULL; |
|
} |
|
|
|
ssize_t gserial_set_console(unsigned char port_num, const char *page, size_t count) |
|
{ |
|
struct gs_port *port; |
|
bool enable; |
|
int ret; |
|
|
|
ret = strtobool(page, &enable); |
|
if (ret) |
|
return ret; |
|
|
|
mutex_lock(&ports[port_num].lock); |
|
port = ports[port_num].port; |
|
|
|
if (WARN_ON(port == NULL)) { |
|
ret = -ENXIO; |
|
goto out; |
|
} |
|
|
|
if (enable) |
|
ret = gs_console_init(port); |
|
else |
|
gs_console_exit(port); |
|
out: |
|
mutex_unlock(&ports[port_num].lock); |
|
|
|
return ret < 0 ? ret : count; |
|
} |
|
EXPORT_SYMBOL_GPL(gserial_set_console); |
|
|
|
ssize_t gserial_get_console(unsigned char port_num, char *page) |
|
{ |
|
struct gs_port *port; |
|
ssize_t ret; |
|
|
|
mutex_lock(&ports[port_num].lock); |
|
port = ports[port_num].port; |
|
|
|
if (WARN_ON(port == NULL)) |
|
ret = -ENXIO; |
|
else |
|
ret = sprintf(page, "%u\n", !!port->console); |
|
|
|
mutex_unlock(&ports[port_num].lock); |
|
|
|
return ret; |
|
} |
|
EXPORT_SYMBOL_GPL(gserial_get_console); |
|
|
|
#else |
|
|
|
static int gs_console_connect(struct gs_port *port) |
|
{ |
|
return 0; |
|
} |
|
|
|
static void gs_console_disconnect(struct gs_port *port) |
|
{ |
|
} |
|
|
|
static int gs_console_init(struct gs_port *port) |
|
{ |
|
return -ENOSYS; |
|
} |
|
|
|
static void gs_console_exit(struct gs_port *port) |
|
{ |
|
} |
|
|
|
#endif |
|
|
|
static int |
|
gs_port_alloc(unsigned port_num, struct usb_cdc_line_coding *coding) |
|
{ |
|
struct gs_port *port; |
|
int ret = 0; |
|
|
|
mutex_lock(&ports[port_num].lock); |
|
if (ports[port_num].port) { |
|
ret = -EBUSY; |
|
goto out; |
|
} |
|
|
|
port = kzalloc(sizeof(struct gs_port), GFP_KERNEL); |
|
if (port == NULL) { |
|
ret = -ENOMEM; |
|
goto out; |
|
} |
|
|
|
tty_port_init(&port->port); |
|
spin_lock_init(&port->port_lock); |
|
init_waitqueue_head(&port->drain_wait); |
|
init_waitqueue_head(&port->close_wait); |
|
|
|
INIT_DELAYED_WORK(&port->push, gs_rx_push); |
|
|
|
INIT_LIST_HEAD(&port->read_pool); |
|
INIT_LIST_HEAD(&port->read_queue); |
|
INIT_LIST_HEAD(&port->write_pool); |
|
|
|
port->port_num = port_num; |
|
port->port_line_coding = *coding; |
|
|
|
ports[port_num].port = port; |
|
out: |
|
mutex_unlock(&ports[port_num].lock); |
|
return ret; |
|
} |
|
|
|
static int gs_closed(struct gs_port *port) |
|
{ |
|
int cond; |
|
|
|
spin_lock_irq(&port->port_lock); |
|
cond = port->port.count == 0; |
|
spin_unlock_irq(&port->port_lock); |
|
|
|
return cond; |
|
} |
|
|
|
static void gserial_free_port(struct gs_port *port) |
|
{ |
|
cancel_delayed_work_sync(&port->push); |
|
/* wait for old opens to finish */ |
|
wait_event(port->close_wait, gs_closed(port)); |
|
WARN_ON(port->port_usb != NULL); |
|
tty_port_destroy(&port->port); |
|
kfree(port); |
|
} |
|
|
|
void gserial_free_line(unsigned char port_num) |
|
{ |
|
struct gs_port *port; |
|
|
|
mutex_lock(&ports[port_num].lock); |
|
if (WARN_ON(!ports[port_num].port)) { |
|
mutex_unlock(&ports[port_num].lock); |
|
return; |
|
} |
|
port = ports[port_num].port; |
|
gs_console_exit(port); |
|
ports[port_num].port = NULL; |
|
mutex_unlock(&ports[port_num].lock); |
|
|
|
gserial_free_port(port); |
|
tty_unregister_device(gs_tty_driver, port_num); |
|
} |
|
EXPORT_SYMBOL_GPL(gserial_free_line); |
|
|
|
int gserial_alloc_line_no_console(unsigned char *line_num) |
|
{ |
|
struct usb_cdc_line_coding coding; |
|
struct gs_port *port; |
|
struct device *tty_dev; |
|
int ret; |
|
int port_num; |
|
|
|
coding.dwDTERate = cpu_to_le32(9600); |
|
coding.bCharFormat = 8; |
|
coding.bParityType = USB_CDC_NO_PARITY; |
|
coding.bDataBits = USB_CDC_1_STOP_BITS; |
|
|
|
for (port_num = 0; port_num < MAX_U_SERIAL_PORTS; port_num++) { |
|
ret = gs_port_alloc(port_num, &coding); |
|
if (ret == -EBUSY) |
|
continue; |
|
if (ret) |
|
return ret; |
|
break; |
|
} |
|
if (ret) |
|
return ret; |
|
|
|
/* ... and sysfs class devices, so mdev/udev make /dev/ttyGS* */ |
|
|
|
port = ports[port_num].port; |
|
tty_dev = tty_port_register_device(&port->port, |
|
gs_tty_driver, port_num, NULL); |
|
if (IS_ERR(tty_dev)) { |
|
pr_err("%s: failed to register tty for port %d, err %ld\n", |
|
__func__, port_num, PTR_ERR(tty_dev)); |
|
|
|
ret = PTR_ERR(tty_dev); |
|
mutex_lock(&ports[port_num].lock); |
|
ports[port_num].port = NULL; |
|
mutex_unlock(&ports[port_num].lock); |
|
gserial_free_port(port); |
|
goto err; |
|
} |
|
*line_num = port_num; |
|
err: |
|
return ret; |
|
} |
|
EXPORT_SYMBOL_GPL(gserial_alloc_line_no_console); |
|
|
|
int gserial_alloc_line(unsigned char *line_num) |
|
{ |
|
int ret = gserial_alloc_line_no_console(line_num); |
|
|
|
if (!ret && !*line_num) |
|
gs_console_init(ports[*line_num].port); |
|
|
|
return ret; |
|
} |
|
EXPORT_SYMBOL_GPL(gserial_alloc_line); |
|
|
|
/** |
|
* gserial_connect - notify TTY I/O glue that USB link is active |
|
* @gser: the function, set up with endpoints and descriptors |
|
* @port_num: which port is active |
|
* Context: any (usually from irq) |
|
* |
|
* This is called activate endpoints and let the TTY layer know that |
|
* the connection is active ... not unlike "carrier detect". It won't |
|
* necessarily start I/O queues; unless the TTY is held open by any |
|
* task, there would be no point. However, the endpoints will be |
|
* activated so the USB host can perform I/O, subject to basic USB |
|
* hardware flow control. |
|
* |
|
* Caller needs to have set up the endpoints and USB function in @dev |
|
* before calling this, as well as the appropriate (speed-specific) |
|
* endpoint descriptors, and also have allocate @port_num by calling |
|
* @gserial_alloc_line(). |
|
* |
|
* Returns negative errno or zero. |
|
* On success, ep->driver_data will be overwritten. |
|
*/ |
|
int gserial_connect(struct gserial *gser, u8 port_num) |
|
{ |
|
struct gs_port *port; |
|
unsigned long flags; |
|
int status; |
|
|
|
if (port_num >= MAX_U_SERIAL_PORTS) |
|
return -ENXIO; |
|
|
|
port = ports[port_num].port; |
|
if (!port) { |
|
pr_err("serial line %d not allocated.\n", port_num); |
|
return -EINVAL; |
|
} |
|
if (port->port_usb) { |
|
pr_err("serial line %d is in use.\n", port_num); |
|
return -EBUSY; |
|
} |
|
|
|
/* activate the endpoints */ |
|
status = usb_ep_enable(gser->in); |
|
if (status < 0) |
|
return status; |
|
gser->in->driver_data = port; |
|
|
|
status = usb_ep_enable(gser->out); |
|
if (status < 0) |
|
goto fail_out; |
|
gser->out->driver_data = port; |
|
|
|
/* then tell the tty glue that I/O can work */ |
|
spin_lock_irqsave(&port->port_lock, flags); |
|
gser->ioport = port; |
|
port->port_usb = gser; |
|
|
|
/* REVISIT unclear how best to handle this state... |
|
* we don't really couple it with the Linux TTY. |
|
*/ |
|
gser->port_line_coding = port->port_line_coding; |
|
|
|
/* REVISIT if waiting on "carrier detect", signal. */ |
|
|
|
/* if it's already open, start I/O ... and notify the serial |
|
* protocol about open/close status (connect/disconnect). |
|
*/ |
|
if (port->port.count) { |
|
pr_debug("gserial_connect: start ttyGS%d\n", port->port_num); |
|
gs_start_io(port); |
|
if (gser->connect) |
|
gser->connect(gser); |
|
} else { |
|
if (gser->disconnect) |
|
gser->disconnect(gser); |
|
} |
|
|
|
status = gs_console_connect(port); |
|
spin_unlock_irqrestore(&port->port_lock, flags); |
|
|
|
return status; |
|
|
|
fail_out: |
|
usb_ep_disable(gser->in); |
|
return status; |
|
} |
|
EXPORT_SYMBOL_GPL(gserial_connect); |
|
/** |
|
* gserial_disconnect - notify TTY I/O glue that USB link is inactive |
|
* @gser: the function, on which gserial_connect() was called |
|
* Context: any (usually from irq) |
|
* |
|
* This is called to deactivate endpoints and let the TTY layer know |
|
* that the connection went inactive ... not unlike "hangup". |
|
* |
|
* On return, the state is as if gserial_connect() had never been called; |
|
* there is no active USB I/O on these endpoints. |
|
*/ |
|
void gserial_disconnect(struct gserial *gser) |
|
{ |
|
struct gs_port *port = gser->ioport; |
|
unsigned long flags; |
|
|
|
if (!port) |
|
return; |
|
|
|
/* tell the TTY glue not to do I/O here any more */ |
|
spin_lock_irqsave(&port->port_lock, flags); |
|
|
|
gs_console_disconnect(port); |
|
|
|
/* REVISIT as above: how best to track this? */ |
|
port->port_line_coding = gser->port_line_coding; |
|
|
|
port->port_usb = NULL; |
|
gser->ioport = NULL; |
|
if (port->port.count > 0) { |
|
wake_up_interruptible(&port->drain_wait); |
|
if (port->port.tty) |
|
tty_hangup(port->port.tty); |
|
} |
|
port->suspended = false; |
|
spin_unlock_irqrestore(&port->port_lock, flags); |
|
|
|
/* disable endpoints, aborting down any active I/O */ |
|
usb_ep_disable(gser->out); |
|
usb_ep_disable(gser->in); |
|
|
|
/* finally, free any unused/unusable I/O buffers */ |
|
spin_lock_irqsave(&port->port_lock, flags); |
|
if (port->port.count == 0) |
|
kfifo_free(&port->port_write_buf); |
|
gs_free_requests(gser->out, &port->read_pool, NULL); |
|
gs_free_requests(gser->out, &port->read_queue, NULL); |
|
gs_free_requests(gser->in, &port->write_pool, NULL); |
|
|
|
port->read_allocated = port->read_started = |
|
port->write_allocated = port->write_started = 0; |
|
|
|
spin_unlock_irqrestore(&port->port_lock, flags); |
|
} |
|
EXPORT_SYMBOL_GPL(gserial_disconnect); |
|
|
|
void gserial_suspend(struct gserial *gser) |
|
{ |
|
struct gs_port *port = gser->ioport; |
|
unsigned long flags; |
|
|
|
spin_lock_irqsave(&port->port_lock, flags); |
|
port->suspended = true; |
|
spin_unlock_irqrestore(&port->port_lock, flags); |
|
} |
|
EXPORT_SYMBOL_GPL(gserial_suspend); |
|
|
|
void gserial_resume(struct gserial *gser) |
|
{ |
|
struct gs_port *port = gser->ioport; |
|
unsigned long flags; |
|
|
|
spin_lock_irqsave(&port->port_lock, flags); |
|
port->suspended = false; |
|
if (!port->start_delayed) { |
|
spin_unlock_irqrestore(&port->port_lock, flags); |
|
return; |
|
} |
|
|
|
pr_debug("delayed start ttyGS%d\n", port->port_num); |
|
gs_start_io(port); |
|
if (gser->connect) |
|
gser->connect(gser); |
|
port->start_delayed = false; |
|
spin_unlock_irqrestore(&port->port_lock, flags); |
|
} |
|
EXPORT_SYMBOL_GPL(gserial_resume); |
|
|
|
static int userial_init(void) |
|
{ |
|
unsigned i; |
|
int status; |
|
|
|
gs_tty_driver = alloc_tty_driver(MAX_U_SERIAL_PORTS); |
|
if (!gs_tty_driver) |
|
return -ENOMEM; |
|
|
|
gs_tty_driver->driver_name = "g_serial"; |
|
gs_tty_driver->name = "ttyGS"; |
|
/* uses dynamically assigned dev_t values */ |
|
|
|
gs_tty_driver->type = TTY_DRIVER_TYPE_SERIAL; |
|
gs_tty_driver->subtype = SERIAL_TYPE_NORMAL; |
|
gs_tty_driver->flags = TTY_DRIVER_REAL_RAW | TTY_DRIVER_DYNAMIC_DEV; |
|
gs_tty_driver->init_termios = tty_std_termios; |
|
|
|
/* 9600-8-N-1 ... matches defaults expected by "usbser.sys" on |
|
* MS-Windows. Otherwise, most of these flags shouldn't affect |
|
* anything unless we were to actually hook up to a serial line. |
|
*/ |
|
gs_tty_driver->init_termios.c_cflag = |
|
B9600 | CS8 | CREAD | HUPCL | CLOCAL; |
|
gs_tty_driver->init_termios.c_ispeed = 9600; |
|
gs_tty_driver->init_termios.c_ospeed = 9600; |
|
|
|
tty_set_operations(gs_tty_driver, &gs_tty_ops); |
|
for (i = 0; i < MAX_U_SERIAL_PORTS; i++) |
|
mutex_init(&ports[i].lock); |
|
|
|
/* export the driver ... */ |
|
status = tty_register_driver(gs_tty_driver); |
|
if (status) { |
|
pr_err("%s: cannot register, err %d\n", |
|
__func__, status); |
|
goto fail; |
|
} |
|
|
|
pr_debug("%s: registered %d ttyGS* device%s\n", __func__, |
|
MAX_U_SERIAL_PORTS, |
|
(MAX_U_SERIAL_PORTS == 1) ? "" : "s"); |
|
|
|
return status; |
|
fail: |
|
put_tty_driver(gs_tty_driver); |
|
gs_tty_driver = NULL; |
|
return status; |
|
} |
|
module_init(userial_init); |
|
|
|
static void userial_cleanup(void) |
|
{ |
|
tty_unregister_driver(gs_tty_driver); |
|
put_tty_driver(gs_tty_driver); |
|
gs_tty_driver = NULL; |
|
} |
|
module_exit(userial_cleanup); |
|
|
|
MODULE_LICENSE("GPL");
|
|
|