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566 lines
14 KiB
566 lines
14 KiB
// SPDX-License-Identifier: GPL-2.0 |
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/* |
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* Device driver for the via ADB on (many) Mac II-class machines |
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* |
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* Based on the original ADB keyboard handler Copyright (c) 1997 Alan Cox |
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* Also derived from code Copyright (C) 1996 Paul Mackerras. |
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* |
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* With various updates provided over the years by Michael Schmitz, |
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* Guideo Koerber and others. |
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* |
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* Rewrite for Unified ADB by Joshua M. Thompson ([email protected]) |
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* |
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* 1999-08-02 (jmt) - Initial rewrite for Unified ADB. |
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* 2000-03-29 Tony Mantler <[email protected]> |
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* - Big overhaul, should actually work now. |
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* 2006-12-31 Finn Thain - Another overhaul. |
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* |
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* Suggested reading: |
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* Inside Macintosh, ch. 5 ADB Manager |
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* Guide to the Macinstosh Family Hardware, ch. 8 Apple Desktop Bus |
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* Rockwell R6522 VIA datasheet |
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* |
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* Apple's "ADB Analyzer" bus sniffer is invaluable: |
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* ftp://ftp.apple.com/developer/Tool_Chest/Devices_-_Hardware/Apple_Desktop_Bus/ |
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*/ |
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#include <stdarg.h> |
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#include <linux/types.h> |
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#include <linux/errno.h> |
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#include <linux/kernel.h> |
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#include <linux/delay.h> |
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#include <linux/adb.h> |
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#include <linux/interrupt.h> |
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#include <linux/init.h> |
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#include <asm/macintosh.h> |
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#include <asm/macints.h> |
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#include <asm/mac_via.h> |
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|
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static volatile unsigned char *via; |
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|
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/* VIA registers - spaced 0x200 bytes apart */ |
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#define RS 0x200 /* skip between registers */ |
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#define B 0 /* B-side data */ |
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#define A RS /* A-side data */ |
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#define DIRB (2*RS) /* B-side direction (1=output) */ |
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#define DIRA (3*RS) /* A-side direction (1=output) */ |
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#define T1CL (4*RS) /* Timer 1 ctr/latch (low 8 bits) */ |
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#define T1CH (5*RS) /* Timer 1 counter (high 8 bits) */ |
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#define T1LL (6*RS) /* Timer 1 latch (low 8 bits) */ |
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#define T1LH (7*RS) /* Timer 1 latch (high 8 bits) */ |
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#define T2CL (8*RS) /* Timer 2 ctr/latch (low 8 bits) */ |
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#define T2CH (9*RS) /* Timer 2 counter (high 8 bits) */ |
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#define SR (10*RS) /* Shift register */ |
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#define ACR (11*RS) /* Auxiliary control register */ |
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#define PCR (12*RS) /* Peripheral control register */ |
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#define IFR (13*RS) /* Interrupt flag register */ |
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#define IER (14*RS) /* Interrupt enable register */ |
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#define ANH (15*RS) /* A-side data, no handshake */ |
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/* Bits in B data register: all active low */ |
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#define CTLR_IRQ 0x08 /* Controller rcv status (input) */ |
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#define ST_MASK 0x30 /* mask for selecting ADB state bits */ |
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/* Bits in ACR */ |
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#define SR_CTRL 0x1c /* Shift register control bits */ |
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#define SR_EXT 0x0c /* Shift on external clock */ |
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#define SR_OUT 0x10 /* Shift out if 1 */ |
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/* Bits in IFR and IER */ |
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#define IER_SET 0x80 /* set bits in IER */ |
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#define IER_CLR 0 /* clear bits in IER */ |
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#define SR_INT 0x04 /* Shift register full/empty */ |
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/* ADB transaction states according to GMHW */ |
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#define ST_CMD 0x00 /* ADB state: command byte */ |
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#define ST_EVEN 0x10 /* ADB state: even data byte */ |
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#define ST_ODD 0x20 /* ADB state: odd data byte */ |
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#define ST_IDLE 0x30 /* ADB state: idle, nothing to send */ |
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/* ADB command byte structure */ |
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#define ADDR_MASK 0xF0 |
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#define CMD_MASK 0x0F |
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#define OP_MASK 0x0C |
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#define TALK 0x0C |
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static int macii_init_via(void); |
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static void macii_start(void); |
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static irqreturn_t macii_interrupt(int irq, void *arg); |
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static void macii_queue_poll(void); |
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static int macii_probe(void); |
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static int macii_init(void); |
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static int macii_send_request(struct adb_request *req, int sync); |
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static int macii_write(struct adb_request *req); |
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static int macii_autopoll(int devs); |
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static void macii_poll(void); |
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static int macii_reset_bus(void); |
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struct adb_driver via_macii_driver = { |
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.name = "Mac II", |
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.probe = macii_probe, |
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.init = macii_init, |
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.send_request = macii_send_request, |
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.autopoll = macii_autopoll, |
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.poll = macii_poll, |
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.reset_bus = macii_reset_bus, |
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}; |
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static enum macii_state { |
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idle, |
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sending, |
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reading, |
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} macii_state; |
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static struct adb_request *current_req; /* first request struct in the queue */ |
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static struct adb_request *last_req; /* last request struct in the queue */ |
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static unsigned char reply_buf[16]; /* storage for autopolled replies */ |
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static unsigned char *reply_ptr; /* next byte in reply_buf or req->reply */ |
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static bool reading_reply; /* store reply in reply_buf else req->reply */ |
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static int data_index; /* index of the next byte to send from req->data */ |
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static int reply_len; /* number of bytes received in reply_buf or req->reply */ |
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static int status; /* VIA's ADB status bits captured upon interrupt */ |
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static bool bus_timeout; /* no data was sent by the device */ |
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static bool srq_asserted; /* have to poll for the device that asserted it */ |
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static u8 last_cmd; /* the most recent command byte transmitted */ |
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static u8 last_talk_cmd; /* the most recent Talk command byte transmitted */ |
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static u8 last_poll_cmd; /* the most recent Talk R0 command byte transmitted */ |
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static unsigned int autopoll_devs; /* bits set are device addresses to poll */ |
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/* Check for MacII style ADB */ |
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static int macii_probe(void) |
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{ |
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if (macintosh_config->adb_type != MAC_ADB_II) |
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return -ENODEV; |
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via = via1; |
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pr_info("adb: Mac II ADB Driver v1.0 for Unified ADB\n"); |
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return 0; |
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} |
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/* Initialize the driver */ |
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static int macii_init(void) |
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{ |
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unsigned long flags; |
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int err; |
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local_irq_save(flags); |
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err = macii_init_via(); |
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if (err) |
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goto out; |
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err = request_irq(IRQ_MAC_ADB, macii_interrupt, 0, "ADB", |
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macii_interrupt); |
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if (err) |
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goto out; |
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macii_state = idle; |
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out: |
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local_irq_restore(flags); |
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return err; |
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} |
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/* initialize the hardware */ |
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static int macii_init_via(void) |
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{ |
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unsigned char x; |
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/* We want CTLR_IRQ as input and ST_EVEN | ST_ODD as output lines. */ |
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via[DIRB] = (via[DIRB] | ST_EVEN | ST_ODD) & ~CTLR_IRQ; |
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/* Set up state: idle */ |
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via[B] |= ST_IDLE; |
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/* Shift register on input */ |
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via[ACR] = (via[ACR] & ~SR_CTRL) | SR_EXT; |
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/* Wipe any pending data and int */ |
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x = via[SR]; |
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return 0; |
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} |
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/* Send an ADB poll (Talk Register 0 command prepended to the request queue) */ |
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static void macii_queue_poll(void) |
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{ |
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static struct adb_request req; |
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unsigned char poll_command; |
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unsigned int poll_addr; |
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/* This only polls devices in the autopoll list, which assumes that |
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* unprobed devices never assert SRQ. That could happen if a device was |
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* plugged in after the adb bus scan. Unplugging it again will resolve |
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* the problem. This behaviour is similar to MacOS. |
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*/ |
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if (!autopoll_devs) |
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return; |
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/* The device most recently polled may not be the best device to poll |
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* right now. Some other device(s) may have signalled SRQ (the active |
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* device won't do that). Or the autopoll list may have been changed. |
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* Try polling the next higher address. |
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*/ |
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poll_addr = (last_poll_cmd & ADDR_MASK) >> 4; |
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if ((srq_asserted && last_cmd == last_poll_cmd) || |
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!(autopoll_devs & (1 << poll_addr))) { |
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unsigned int higher_devs; |
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higher_devs = autopoll_devs & -(1 << (poll_addr + 1)); |
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poll_addr = ffs(higher_devs ? higher_devs : autopoll_devs) - 1; |
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} |
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/* Send a Talk Register 0 command */ |
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poll_command = ADB_READREG(poll_addr, 0); |
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/* No need to repeat this Talk command. The transceiver will do that |
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* as long as it is idle. |
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*/ |
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if (poll_command == last_cmd) |
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return; |
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adb_request(&req, NULL, ADBREQ_NOSEND, 1, poll_command); |
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req.sent = 0; |
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req.complete = 0; |
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req.reply_len = 0; |
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req.next = current_req; |
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if (WARN_ON(current_req)) { |
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current_req = &req; |
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} else { |
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current_req = &req; |
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last_req = &req; |
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} |
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} |
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/* Send an ADB request; if sync, poll out the reply 'till it's done */ |
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static int macii_send_request(struct adb_request *req, int sync) |
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{ |
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int err; |
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err = macii_write(req); |
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if (err) |
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return err; |
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if (sync) |
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while (!req->complete) |
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macii_poll(); |
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return 0; |
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} |
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/* Send an ADB request (append to request queue) */ |
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static int macii_write(struct adb_request *req) |
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{ |
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unsigned long flags; |
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if (req->nbytes < 2 || req->data[0] != ADB_PACKET || req->nbytes > 15) { |
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req->complete = 1; |
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return -EINVAL; |
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} |
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req->next = NULL; |
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req->sent = 0; |
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req->complete = 0; |
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req->reply_len = 0; |
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local_irq_save(flags); |
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if (current_req != NULL) { |
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last_req->next = req; |
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last_req = req; |
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} else { |
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current_req = req; |
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last_req = req; |
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if (macii_state == idle) |
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macii_start(); |
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} |
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local_irq_restore(flags); |
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return 0; |
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} |
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/* Start auto-polling */ |
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static int macii_autopoll(int devs) |
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{ |
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unsigned long flags; |
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local_irq_save(flags); |
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/* bit 1 == device 1, and so on. */ |
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autopoll_devs = (unsigned int)devs & 0xFFFE; |
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if (!current_req) { |
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macii_queue_poll(); |
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if (current_req && macii_state == idle) |
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macii_start(); |
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} |
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local_irq_restore(flags); |
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return 0; |
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} |
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/* Prod the chip without interrupts */ |
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static void macii_poll(void) |
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{ |
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macii_interrupt(0, NULL); |
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} |
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/* Reset the bus */ |
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static int macii_reset_bus(void) |
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{ |
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struct adb_request req; |
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/* Command = 0, Address = ignored */ |
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adb_request(&req, NULL, ADBREQ_NOSEND, 1, ADB_BUSRESET); |
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macii_send_request(&req, 1); |
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/* Don't want any more requests during the Global Reset low time. */ |
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udelay(3000); |
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return 0; |
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} |
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/* Start sending ADB packet */ |
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static void macii_start(void) |
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{ |
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struct adb_request *req; |
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req = current_req; |
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/* Now send it. Be careful though, that first byte of the request |
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* is actually ADB_PACKET; the real data begins at index 1! |
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* And req->nbytes is the number of bytes of real data plus one. |
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*/ |
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/* Output mode */ |
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via[ACR] |= SR_OUT; |
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/* Load data */ |
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via[SR] = req->data[1]; |
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/* set ADB state to 'command' */ |
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via[B] = (via[B] & ~ST_MASK) | ST_CMD; |
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macii_state = sending; |
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data_index = 2; |
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bus_timeout = false; |
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srq_asserted = false; |
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} |
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/* |
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* The notorious ADB interrupt handler - does all of the protocol handling. |
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* Relies on the ADB controller sending and receiving data, thereby |
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* generating shift register interrupts (SR_INT) for us. This means there has |
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* to be activity on the ADB bus. The chip will poll to achieve this. |
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* |
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* The VIA Port B output signalling works as follows. After the ADB transceiver |
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* sees a transition on the PB4 and PB5 lines it will crank over the VIA shift |
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* register which eventually raises the SR_INT interrupt. The PB4/PB5 outputs |
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* are toggled with each byte as the ADB transaction progresses. |
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* |
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* Request with no reply expected (and empty transceiver buffer): |
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* CMD -> IDLE |
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* Request with expected reply packet (or with buffered autopoll packet): |
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* CMD -> EVEN -> ODD -> EVEN -> ... -> IDLE |
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* Unsolicited packet: |
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* IDLE -> EVEN -> ODD -> EVEN -> ... -> IDLE |
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*/ |
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static irqreturn_t macii_interrupt(int irq, void *arg) |
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{ |
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int x; |
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struct adb_request *req; |
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unsigned long flags; |
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local_irq_save(flags); |
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if (!arg) { |
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/* Clear the SR IRQ flag when polling. */ |
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if (via[IFR] & SR_INT) |
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via[IFR] = SR_INT; |
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else { |
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local_irq_restore(flags); |
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return IRQ_NONE; |
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} |
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} |
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status = via[B] & (ST_MASK | CTLR_IRQ); |
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switch (macii_state) { |
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case idle: |
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WARN_ON((status & ST_MASK) != ST_IDLE); |
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reply_ptr = reply_buf; |
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reading_reply = false; |
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bus_timeout = false; |
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srq_asserted = false; |
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x = via[SR]; |
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if (!(status & CTLR_IRQ)) { |
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/* /CTLR_IRQ asserted in idle state means we must |
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* read an autopoll reply from the transceiver buffer. |
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*/ |
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macii_state = reading; |
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*reply_ptr = x; |
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reply_len = 1; |
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} else { |
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/* bus timeout */ |
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reply_len = 0; |
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break; |
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} |
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/* set ADB state = even for first data byte */ |
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via[B] = (via[B] & ~ST_MASK) | ST_EVEN; |
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break; |
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case sending: |
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req = current_req; |
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if (status == (ST_CMD | CTLR_IRQ)) { |
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/* /CTLR_IRQ de-asserted after the command byte means |
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* the host can continue with the transaction. |
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*/ |
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/* Store command byte */ |
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last_cmd = req->data[1]; |
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if ((last_cmd & OP_MASK) == TALK) { |
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last_talk_cmd = last_cmd; |
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if ((last_cmd & CMD_MASK) == ADB_READREG(0, 0)) |
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last_poll_cmd = last_cmd; |
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} |
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} |
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if (status == ST_CMD) { |
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/* /CTLR_IRQ asserted after the command byte means we |
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* must read an autopoll reply. The first byte was |
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* lost because the shift register was an output. |
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*/ |
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macii_state = reading; |
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reading_reply = false; |
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reply_ptr = reply_buf; |
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*reply_ptr = last_talk_cmd; |
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reply_len = 1; |
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/* reset to shift in */ |
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via[ACR] &= ~SR_OUT; |
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x = via[SR]; |
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} else if (data_index >= req->nbytes) { |
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req->sent = 1; |
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if (req->reply_expected) { |
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macii_state = reading; |
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reading_reply = true; |
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reply_ptr = req->reply; |
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*reply_ptr = req->data[1]; |
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reply_len = 1; |
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via[ACR] &= ~SR_OUT; |
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x = via[SR]; |
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} else if ((req->data[1] & OP_MASK) == TALK) { |
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macii_state = reading; |
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reading_reply = false; |
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reply_ptr = reply_buf; |
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*reply_ptr = req->data[1]; |
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reply_len = 1; |
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via[ACR] &= ~SR_OUT; |
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x = via[SR]; |
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req->complete = 1; |
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current_req = req->next; |
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if (req->done) |
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(*req->done)(req); |
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} else { |
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macii_state = idle; |
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req->complete = 1; |
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current_req = req->next; |
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if (req->done) |
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(*req->done)(req); |
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break; |
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} |
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} else { |
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via[SR] = req->data[data_index++]; |
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} |
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if ((via[B] & ST_MASK) == ST_CMD) { |
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/* just sent the command byte, set to EVEN */ |
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via[B] = (via[B] & ~ST_MASK) | ST_EVEN; |
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} else { |
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/* invert state bits, toggle ODD/EVEN */ |
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via[B] ^= ST_MASK; |
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} |
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break; |
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case reading: |
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x = via[SR]; |
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WARN_ON((status & ST_MASK) == ST_CMD || |
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(status & ST_MASK) == ST_IDLE); |
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|
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if (!(status & CTLR_IRQ)) { |
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if (status == ST_EVEN && reply_len == 1) { |
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bus_timeout = true; |
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} else if (status == ST_ODD && reply_len == 2) { |
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srq_asserted = true; |
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} else { |
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macii_state = idle; |
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if (bus_timeout) |
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reply_len = 0; |
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if (reading_reply) { |
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struct adb_request *req = current_req; |
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req->reply_len = reply_len; |
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req->complete = 1; |
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current_req = req->next; |
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if (req->done) |
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(*req->done)(req); |
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} else if (reply_len && autopoll_devs && |
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reply_buf[0] == last_poll_cmd) { |
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adb_input(reply_buf, reply_len, 1); |
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} |
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break; |
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} |
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} |
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if (reply_len < ARRAY_SIZE(reply_buf)) { |
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reply_ptr++; |
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*reply_ptr = x; |
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reply_len++; |
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} |
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/* invert state bits, toggle ODD/EVEN */ |
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via[B] ^= ST_MASK; |
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break; |
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default: |
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break; |
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} |
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if (macii_state == idle) { |
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if (!current_req) |
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macii_queue_poll(); |
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if (current_req) |
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macii_start(); |
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if (macii_state == idle) { |
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via[ACR] &= ~SR_OUT; |
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x = via[SR]; |
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via[B] = (via[B] & ~ST_MASK) | ST_IDLE; |
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} |
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} |
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local_irq_restore(flags); |
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return IRQ_HANDLED; |
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}
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