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1// SPDX-License-Identifier: GPL-2.02/*3 * Device driver for the via ADB on (many) Mac II-class machines4 *5 * Based on the original ADB keyboard handler Copyright (c) 1997 Alan Cox6 * Also derived from code Copyright (C) 1996 Paul Mackerras.7 *8 * With various updates provided over the years by Michael Schmitz,9 * Guideo Koerber and others.10 *11 * Rewrite for Unified ADB by Joshua M. Thompson (funaho@jurai.org)12 *13 * 1999-08-02 (jmt) - Initial rewrite for Unified ADB.14 * 2000-03-29 Tony Mantler <tonym@mac.linux-m68k.org>15 * - Big overhaul, should actually work now.16 * 2006-12-31 Finn Thain - Another overhaul.17 *18 * Suggested reading:19 * Inside Macintosh, ch. 5 ADB Manager20 * Guide to the Macinstosh Family Hardware, ch. 8 Apple Desktop Bus21 * Rockwell R6522 VIA datasheet22 *23 * Apple's "ADB Analyzer" bus sniffer is invaluable:24 * ftp://ftp.apple.com/developer/Tool_Chest/Devices_-_Hardware/Apple_Desktop_Bus/25 */26#include <linux/types.h>27#include <linux/errno.h>28#include <linux/kernel.h>29#include <linux/delay.h>30#include <linux/adb.h>31#include <linux/interrupt.h>32#include <linux/init.h>33#include <asm/macintosh.h>34#include <asm/macints.h>35#include <asm/mac_via.h>36 37static volatile unsigned char *via;38 39/* VIA registers - spaced 0x200 bytes apart */40#define RS 0x200 /* skip between registers */41#define B 0 /* B-side data */42#define A RS /* A-side data */43#define DIRB (2*RS) /* B-side direction (1=output) */44#define DIRA (3*RS) /* A-side direction (1=output) */45#define T1CL (4*RS) /* Timer 1 ctr/latch (low 8 bits) */46#define T1CH (5*RS) /* Timer 1 counter (high 8 bits) */47#define T1LL (6*RS) /* Timer 1 latch (low 8 bits) */48#define T1LH (7*RS) /* Timer 1 latch (high 8 bits) */49#define T2CL (8*RS) /* Timer 2 ctr/latch (low 8 bits) */50#define T2CH (9*RS) /* Timer 2 counter (high 8 bits) */51#define SR (10*RS) /* Shift register */52#define ACR (11*RS) /* Auxiliary control register */53#define PCR (12*RS) /* Peripheral control register */54#define IFR (13*RS) /* Interrupt flag register */55#define IER (14*RS) /* Interrupt enable register */56#define ANH (15*RS) /* A-side data, no handshake */57 58/* Bits in B data register: all active low */59#define CTLR_IRQ 0x08 /* Controller rcv status (input) */60#define ST_MASK 0x30 /* mask for selecting ADB state bits */61 62/* Bits in ACR */63#define SR_CTRL 0x1c /* Shift register control bits */64#define SR_EXT 0x0c /* Shift on external clock */65#define SR_OUT 0x10 /* Shift out if 1 */66 67/* Bits in IFR and IER */68#define IER_SET 0x80 /* set bits in IER */69#define IER_CLR 0 /* clear bits in IER */70#define SR_INT 0x04 /* Shift register full/empty */71 72/* ADB transaction states according to GMHW */73#define ST_CMD 0x00 /* ADB state: command byte */74#define ST_EVEN 0x10 /* ADB state: even data byte */75#define ST_ODD 0x20 /* ADB state: odd data byte */76#define ST_IDLE 0x30 /* ADB state: idle, nothing to send */77 78/* ADB command byte structure */79#define ADDR_MASK 0xF080#define CMD_MASK 0x0F81#define OP_MASK 0x0C82#define TALK 0x0C83 84static int macii_init_via(void);85static void macii_start(void);86static irqreturn_t macii_interrupt(int irq, void *arg);87static void macii_queue_poll(void);88 89static int macii_probe(void);90static int macii_init(void);91static int macii_send_request(struct adb_request *req, int sync);92static int macii_write(struct adb_request *req);93static int macii_autopoll(int devs);94static void macii_poll(void);95static int macii_reset_bus(void);96 97struct adb_driver via_macii_driver = {98 .name = "Mac II",99 .probe = macii_probe,100 .init = macii_init,101 .send_request = macii_send_request,102 .autopoll = macii_autopoll,103 .poll = macii_poll,104 .reset_bus = macii_reset_bus,105};106 107static enum macii_state {108 idle,109 sending,110 reading,111} macii_state;112 113static struct adb_request *current_req; /* first request struct in the queue */114static struct adb_request *last_req; /* last request struct in the queue */115static unsigned char reply_buf[16]; /* storage for autopolled replies */116static unsigned char *reply_ptr; /* next byte in reply_buf or req->reply */117static bool reading_reply; /* store reply in reply_buf else req->reply */118static int data_index; /* index of the next byte to send from req->data */119static int reply_len; /* number of bytes received in reply_buf or req->reply */120static int status; /* VIA's ADB status bits captured upon interrupt */121static bool bus_timeout; /* no data was sent by the device */122static bool srq_asserted; /* have to poll for the device that asserted it */123static u8 last_cmd; /* the most recent command byte transmitted */124static u8 last_talk_cmd; /* the most recent Talk command byte transmitted */125static u8 last_poll_cmd; /* the most recent Talk R0 command byte transmitted */126static unsigned int autopoll_devs; /* bits set are device addresses to poll */127 128/* Check for MacII style ADB */129static int macii_probe(void)130{131 if (macintosh_config->adb_type != MAC_ADB_II)132 return -ENODEV;133 134 via = via1;135 136 pr_info("adb: Mac II ADB Driver v1.0 for Unified ADB\n");137 return 0;138}139 140/* Initialize the driver */141static int macii_init(void)142{143 int err;144 145 err = macii_init_via();146 if (err)147 return err;148 149 err = request_irq(IRQ_MAC_ADB, macii_interrupt, 0, "ADB",150 macii_interrupt);151 if (err)152 return err;153 154 macii_state = idle;155 return 0;156}157 158/* initialize the hardware */159static int macii_init_via(void)160{161 unsigned char x;162 163 /* We want CTLR_IRQ as input and ST_EVEN | ST_ODD as output lines. */164 via[DIRB] = (via[DIRB] | ST_EVEN | ST_ODD) & ~CTLR_IRQ;165 166 /* Set up state: idle */167 via[B] |= ST_IDLE;168 169 /* Shift register on input */170 via[ACR] = (via[ACR] & ~SR_CTRL) | SR_EXT;171 172 /* Wipe any pending data and int */173 x = via[SR];174 175 return 0;176}177 178/* Send an ADB poll (Talk Register 0 command prepended to the request queue) */179static void macii_queue_poll(void)180{181 static struct adb_request req;182 unsigned char poll_command;183 unsigned int poll_addr;184 185 /* This only polls devices in the autopoll list, which assumes that186 * unprobed devices never assert SRQ. That could happen if a device was187 * plugged in after the adb bus scan. Unplugging it again will resolve188 * the problem. This behaviour is similar to MacOS.189 */190 if (!autopoll_devs)191 return;192 193 /* The device most recently polled may not be the best device to poll194 * right now. Some other device(s) may have signalled SRQ (the active195 * device won't do that). Or the autopoll list may have been changed.196 * Try polling the next higher address.197 */198 poll_addr = (last_poll_cmd & ADDR_MASK) >> 4;199 if ((srq_asserted && last_cmd == last_poll_cmd) ||200 !(autopoll_devs & (1 << poll_addr))) {201 unsigned int higher_devs;202 203 higher_devs = autopoll_devs & -(1 << (poll_addr + 1));204 poll_addr = ffs(higher_devs ? higher_devs : autopoll_devs) - 1;205 }206 207 /* Send a Talk Register 0 command */208 poll_command = ADB_READREG(poll_addr, 0);209 210 /* No need to repeat this Talk command. The transceiver will do that211 * as long as it is idle.212 */213 if (poll_command == last_cmd)214 return;215 216 adb_request(&req, NULL, ADBREQ_NOSEND, 1, poll_command);217 218 req.sent = 0;219 req.complete = 0;220 req.reply_len = 0;221 req.next = current_req;222 223 if (WARN_ON(current_req)) {224 current_req = &req;225 } else {226 current_req = &req;227 last_req = &req;228 }229}230 231/* Send an ADB request; if sync, poll out the reply 'till it's done */232static int macii_send_request(struct adb_request *req, int sync)233{234 int err;235 236 err = macii_write(req);237 if (err)238 return err;239 240 if (sync)241 while (!req->complete)242 macii_poll();243 244 return 0;245}246 247/* Send an ADB request (append to request queue) */248static int macii_write(struct adb_request *req)249{250 unsigned long flags;251 252 if (req->nbytes < 2 || req->data[0] != ADB_PACKET || req->nbytes > 15) {253 req->complete = 1;254 return -EINVAL;255 }256 257 req->next = NULL;258 req->sent = 0;259 req->complete = 0;260 req->reply_len = 0;261 262 local_irq_save(flags);263 264 if (current_req != NULL) {265 last_req->next = req;266 last_req = req;267 } else {268 current_req = req;269 last_req = req;270 if (macii_state == idle)271 macii_start();272 }273 274 local_irq_restore(flags);275 276 return 0;277}278 279/* Start auto-polling */280static int macii_autopoll(int devs)281{282 unsigned long flags;283 284 local_irq_save(flags);285 286 /* bit 1 == device 1, and so on. */287 autopoll_devs = (unsigned int)devs & 0xFFFE;288 289 if (!current_req) {290 macii_queue_poll();291 if (current_req && macii_state == idle)292 macii_start();293 }294 295 local_irq_restore(flags);296 297 return 0;298}299 300/* Prod the chip without interrupts */301static void macii_poll(void)302{303 macii_interrupt(0, NULL);304}305 306/* Reset the bus */307static int macii_reset_bus(void)308{309 struct adb_request req;310 311 /* Command = 0, Address = ignored */312 adb_request(&req, NULL, ADBREQ_NOSEND, 1, ADB_BUSRESET);313 macii_send_request(&req, 1);314 315 /* Don't want any more requests during the Global Reset low time. */316 udelay(3000);317 318 return 0;319}320 321/* Start sending ADB packet */322static void macii_start(void)323{324 struct adb_request *req;325 326 req = current_req;327 328 /* Now send it. Be careful though, that first byte of the request329 * is actually ADB_PACKET; the real data begins at index 1!330 * And req->nbytes is the number of bytes of real data plus one.331 */332 333 /* Output mode */334 via[ACR] |= SR_OUT;335 /* Load data */336 via[SR] = req->data[1];337 /* set ADB state to 'command' */338 via[B] = (via[B] & ~ST_MASK) | ST_CMD;339 340 macii_state = sending;341 data_index = 2;342 343 bus_timeout = false;344 srq_asserted = false;345}346 347/*348 * The notorious ADB interrupt handler - does all of the protocol handling.349 * Relies on the ADB controller sending and receiving data, thereby350 * generating shift register interrupts (SR_INT) for us. This means there has351 * to be activity on the ADB bus. The chip will poll to achieve this.352 *353 * The VIA Port B output signalling works as follows. After the ADB transceiver354 * sees a transition on the PB4 and PB5 lines it will crank over the VIA shift355 * register which eventually raises the SR_INT interrupt. The PB4/PB5 outputs356 * are toggled with each byte as the ADB transaction progresses.357 *358 * Request with no reply expected (and empty transceiver buffer):359 * CMD -> IDLE360 * Request with expected reply packet (or with buffered autopoll packet):361 * CMD -> EVEN -> ODD -> EVEN -> ... -> IDLE362 * Unsolicited packet:363 * IDLE -> EVEN -> ODD -> EVEN -> ... -> IDLE364 */365static irqreturn_t macii_interrupt(int irq, void *arg)366{367 int x;368 struct adb_request *req;369 unsigned long flags;370 371 local_irq_save(flags);372 373 if (!arg) {374 /* Clear the SR IRQ flag when polling. */375 if (via[IFR] & SR_INT)376 via[IFR] = SR_INT;377 else {378 local_irq_restore(flags);379 return IRQ_NONE;380 }381 }382 383 status = via[B] & (ST_MASK | CTLR_IRQ);384 385 switch (macii_state) {386 case idle:387 WARN_ON((status & ST_MASK) != ST_IDLE);388 389 reply_ptr = reply_buf;390 reading_reply = false;391 392 bus_timeout = false;393 srq_asserted = false;394 395 x = via[SR];396 397 if (!(status & CTLR_IRQ)) {398 /* /CTLR_IRQ asserted in idle state means we must399 * read an autopoll reply from the transceiver buffer.400 */401 macii_state = reading;402 *reply_ptr = x;403 reply_len = 1;404 } else {405 /* bus timeout */406 reply_len = 0;407 break;408 }409 410 /* set ADB state = even for first data byte */411 via[B] = (via[B] & ~ST_MASK) | ST_EVEN;412 break;413 414 case sending:415 req = current_req;416 417 if (status == (ST_CMD | CTLR_IRQ)) {418 /* /CTLR_IRQ de-asserted after the command byte means419 * the host can continue with the transaction.420 */421 422 /* Store command byte */423 last_cmd = req->data[1];424 if ((last_cmd & OP_MASK) == TALK) {425 last_talk_cmd = last_cmd;426 if ((last_cmd & CMD_MASK) == ADB_READREG(0, 0))427 last_poll_cmd = last_cmd;428 }429 }430 431 if (status == ST_CMD) {432 /* /CTLR_IRQ asserted after the command byte means we433 * must read an autopoll reply. The first byte was434 * lost because the shift register was an output.435 */436 macii_state = reading;437 438 reading_reply = false;439 reply_ptr = reply_buf;440 *reply_ptr = last_talk_cmd;441 reply_len = 1;442 443 /* reset to shift in */444 via[ACR] &= ~SR_OUT;445 x = via[SR];446 } else if (data_index >= req->nbytes) {447 req->sent = 1;448 449 if (req->reply_expected) {450 macii_state = reading;451 452 reading_reply = true;453 reply_ptr = req->reply;454 *reply_ptr = req->data[1];455 reply_len = 1;456 457 via[ACR] &= ~SR_OUT;458 x = via[SR];459 } else if ((req->data[1] & OP_MASK) == TALK) {460 macii_state = reading;461 462 reading_reply = false;463 reply_ptr = reply_buf;464 *reply_ptr = req->data[1];465 reply_len = 1;466 467 via[ACR] &= ~SR_OUT;468 x = via[SR];469 470 req->complete = 1;471 current_req = req->next;472 if (req->done)473 (*req->done)(req);474 } else {475 macii_state = idle;476 477 req->complete = 1;478 current_req = req->next;479 if (req->done)480 (*req->done)(req);481 break;482 }483 } else {484 via[SR] = req->data[data_index++];485 }486 487 if ((via[B] & ST_MASK) == ST_CMD) {488 /* just sent the command byte, set to EVEN */489 via[B] = (via[B] & ~ST_MASK) | ST_EVEN;490 } else {491 /* invert state bits, toggle ODD/EVEN */492 via[B] ^= ST_MASK;493 }494 break;495 496 case reading:497 x = via[SR];498 WARN_ON((status & ST_MASK) == ST_CMD ||499 (status & ST_MASK) == ST_IDLE);500 501 if (!(status & CTLR_IRQ)) {502 if (status == ST_EVEN && reply_len == 1) {503 bus_timeout = true;504 } else if (status == ST_ODD && reply_len == 2) {505 srq_asserted = true;506 } else {507 macii_state = idle;508 509 if (bus_timeout)510 reply_len = 0;511 512 if (reading_reply) {513 struct adb_request *req = current_req;514 515 req->reply_len = reply_len;516 517 req->complete = 1;518 current_req = req->next;519 if (req->done)520 (*req->done)(req);521 } else if (reply_len && autopoll_devs &&522 reply_buf[0] == last_poll_cmd) {523 adb_input(reply_buf, reply_len, 1);524 }525 break;526 }527 }528 529 if (reply_len < ARRAY_SIZE(reply_buf)) {530 reply_ptr++;531 *reply_ptr = x;532 reply_len++;533 }534 535 /* invert state bits, toggle ODD/EVEN */536 via[B] ^= ST_MASK;537 break;538 539 default:540 break;541 }542 543 if (macii_state == idle) {544 if (!current_req)545 macii_queue_poll();546 547 if (current_req)548 macii_start();549 550 if (macii_state == idle) {551 via[ACR] &= ~SR_OUT;552 x = via[SR];553 via[B] = (via[B] & ~ST_MASK) | ST_IDLE;554 }555 }556 557 local_irq_restore(flags);558 return IRQ_HANDLED;559}560