1 /* 2 * Device driver for the via ADB on (many) Mac II-class machines 3 * 4 * Based on the original ADB keyboard handler Copyright (c) 1997 Alan Cox 5 * Also derived from code Copyright (C) 1996 Paul Mackerras. 6 * 7 * With various updates provided over the years by Michael Schmitz, 8 * Guideo Koerber and others. 9 * 10 * Rewrite for Unified ADB by Joshua M. Thompson (funaho@jurai.org) 11 * 12 * 1999-08-02 (jmt) - Initial rewrite for Unified ADB. 13 * 2000-03-29 Tony Mantler <tonym@mac.linux-m68k.org> 14 * - Big overhaul, should actually work now. 15 */ 16 17 #include <stdarg.h> 18 #include <linux/types.h> 19 #include <linux/errno.h> 20 #include <linux/kernel.h> 21 #include <linux/delay.h> 22 #include <linux/adb.h> 23 #include <linux/interrupt.h> 24 #include <linux/init.h> 25 #include <asm/macintosh.h> 26 #include <asm/macints.h> 27 #include <asm/machw.h> 28 #include <asm/mac_via.h> 29 #include <asm/io.h> 30 #include <asm/system.h> 31 32 static volatile unsigned char *via; 33 34 /* VIA registers - spaced 0x200 bytes apart */ 35 #define RS 0x200 /* skip between registers */ 36 #define B 0 /* B-side data */ 37 #define A RS /* A-side data */ 38 #define DIRB (2*RS) /* B-side direction (1=output) */ 39 #define DIRA (3*RS) /* A-side direction (1=output) */ 40 #define T1CL (4*RS) /* Timer 1 ctr/latch (low 8 bits) */ 41 #define T1CH (5*RS) /* Timer 1 counter (high 8 bits) */ 42 #define T1LL (6*RS) /* Timer 1 latch (low 8 bits) */ 43 #define T1LH (7*RS) /* Timer 1 latch (high 8 bits) */ 44 #define T2CL (8*RS) /* Timer 2 ctr/latch (low 8 bits) */ 45 #define T2CH (9*RS) /* Timer 2 counter (high 8 bits) */ 46 #define SR (10*RS) /* Shift register */ 47 #define ACR (11*RS) /* Auxiliary control register */ 48 #define PCR (12*RS) /* Peripheral control register */ 49 #define IFR (13*RS) /* Interrupt flag register */ 50 #define IER (14*RS) /* Interrupt enable register */ 51 #define ANH (15*RS) /* A-side data, no handshake */ 52 53 /* Bits in B data register: all active low */ 54 #define TREQ 0x08 /* Transfer request (input) */ 55 #define TACK 0x10 /* Transfer acknowledge (output) */ 56 #define TIP 0x20 /* Transfer in progress (output) */ 57 #define ST_MASK 0x30 /* mask for selecting ADB state bits */ 58 59 /* Bits in ACR */ 60 #define SR_CTRL 0x1c /* Shift register control bits */ 61 #define SR_EXT 0x0c /* Shift on external clock */ 62 #define SR_OUT 0x10 /* Shift out if 1 */ 63 64 /* Bits in IFR and IER */ 65 #define IER_SET 0x80 /* set bits in IER */ 66 #define IER_CLR 0 /* clear bits in IER */ 67 #define SR_INT 0x04 /* Shift register full/empty */ 68 #define SR_DATA 0x08 /* Shift register data */ 69 #define SR_CLOCK 0x10 /* Shift register clock */ 70 71 /* ADB transaction states according to GMHW */ 72 #define ST_CMD 0x00 /* ADB state: command byte */ 73 #define ST_EVEN 0x10 /* ADB state: even data byte */ 74 #define ST_ODD 0x20 /* ADB state: odd data byte */ 75 #define ST_IDLE 0x30 /* ADB state: idle, nothing to send */ 76 77 static int macii_init_via(void); 78 static void macii_start(void); 79 static irqreturn_t macii_interrupt(int irq, void *arg); 80 static void macii_retransmit(int); 81 static void macii_queue_poll(void); 82 83 static int macii_probe(void); 84 static int macii_init(void); 85 static int macii_send_request(struct adb_request *req, int sync); 86 static int macii_write(struct adb_request *req); 87 static int macii_autopoll(int devs); 88 static void macii_poll(void); 89 static int macii_reset_bus(void); 90 91 struct adb_driver via_macii_driver = { 92 "Mac II", 93 macii_probe, 94 macii_init, 95 macii_send_request, 96 macii_autopoll, 97 macii_poll, 98 macii_reset_bus 99 }; 100 101 static enum macii_state { 102 idle, 103 sending, 104 reading, 105 read_done, 106 awaiting_reply 107 } macii_state; 108 109 static int need_poll; 110 static int command_byte; 111 static int last_reply; 112 static int last_active; 113 114 static struct adb_request *current_req; 115 static struct adb_request *last_req; 116 static struct adb_request *retry_req; 117 static unsigned char reply_buf[16]; 118 static unsigned char *reply_ptr; 119 static int reply_len; 120 static int reading_reply; 121 static int data_index; 122 static int first_byte; 123 static int prefix_len; 124 static int status = ST_IDLE|TREQ; 125 static int last_status; 126 static int driver_running; 127 128 /* debug level 10 required for ADB logging (should be && debug_adb, ideally) */ 129 130 /* Check for MacII style ADB */ 131 static int macii_probe(void) 132 { 133 if (macintosh_config->adb_type != MAC_ADB_II) return -ENODEV; 134 135 via = via1; 136 137 printk("adb: Mac II ADB Driver v1.0 for Unified ADB\n"); 138 return 0; 139 } 140 141 /* Initialize the driver */ 142 int macii_init(void) 143 { 144 unsigned long flags; 145 int err; 146 147 local_irq_save(flags); 148 149 err = macii_init_via(); 150 if (err) return err; 151 152 err = request_irq(IRQ_MAC_ADB, macii_interrupt, IRQ_FLG_LOCK, "ADB", 153 macii_interrupt); 154 if (err) return err; 155 156 macii_state = idle; 157 local_irq_restore(flags); 158 return 0; 159 } 160 161 /* initialize the hardware */ 162 static int macii_init_via(void) 163 { 164 unsigned char x; 165 166 /* Set the lines up. We want TREQ as input TACK|TIP as output */ 167 via[DIRB] = (via[DIRB] | TACK | TIP) & ~TREQ; 168 169 /* Set up state: idle */ 170 via[B] |= ST_IDLE; 171 last_status = via[B] & (ST_MASK|TREQ); 172 173 /* Shift register on input */ 174 via[ACR] = (via[ACR] & ~SR_CTRL) | SR_EXT; 175 176 /* Wipe any pending data and int */ 177 x = via[SR]; 178 179 return 0; 180 } 181 182 /* Send an ADB poll (Talk Register 0 command, tagged on the front of the request queue) */ 183 static void macii_queue_poll(void) 184 { 185 static int device = 0; 186 static int in_poll=0; 187 static struct adb_request req; 188 unsigned long flags; 189 190 if (in_poll) printk("macii_queue_poll: double poll!\n"); 191 192 in_poll++; 193 if (++device > 15) device = 1; 194 195 adb_request(&req, NULL, ADBREQ_REPLY|ADBREQ_NOSEND, 1, 196 ADB_READREG(device, 0)); 197 198 local_irq_save(flags); 199 200 req.next = current_req; 201 current_req = &req; 202 203 local_irq_restore(flags); 204 macii_start(); 205 in_poll--; 206 } 207 208 /* Send an ADB retransmit (Talk, appended to the request queue) */ 209 static void macii_retransmit(int device) 210 { 211 static int in_retransmit = 0; 212 static struct adb_request rt; 213 unsigned long flags; 214 215 if (in_retransmit) printk("macii_retransmit: double retransmit!\n"); 216 217 in_retransmit++; 218 219 adb_request(&rt, NULL, ADBREQ_REPLY|ADBREQ_NOSEND, 1, 220 ADB_READREG(device, 0)); 221 222 local_irq_save(flags); 223 224 if (current_req != NULL) { 225 last_req->next = &rt; 226 last_req = &rt; 227 } else { 228 current_req = &rt; 229 last_req = &rt; 230 } 231 232 if (macii_state == idle) macii_start(); 233 234 local_irq_restore(flags); 235 in_retransmit--; 236 } 237 238 /* Send an ADB request; if sync, poll out the reply 'till it's done */ 239 static int macii_send_request(struct adb_request *req, int sync) 240 { 241 int i; 242 243 i = macii_write(req); 244 if (i) return i; 245 246 if (sync) { 247 while (!req->complete) macii_poll(); 248 } 249 return 0; 250 } 251 252 /* Send an ADB request */ 253 static int macii_write(struct adb_request *req) 254 { 255 unsigned long flags; 256 257 if (req->nbytes < 2 || req->data[0] != ADB_PACKET || req->nbytes > 15) { 258 req->complete = 1; 259 return -EINVAL; 260 } 261 262 req->next = NULL; 263 req->sent = 0; 264 req->complete = 0; 265 req->reply_len = 0; 266 267 local_irq_save(flags); 268 269 if (current_req != NULL) { 270 last_req->next = req; 271 last_req = req; 272 } else { 273 current_req = req; 274 last_req = req; 275 if (macii_state == idle) macii_start(); 276 } 277 278 local_irq_restore(flags); 279 return 0; 280 } 281 282 /* Start auto-polling */ 283 static int macii_autopoll(int devs) 284 { 285 /* Just ping a random default address */ 286 if (!(current_req || retry_req)) 287 macii_retransmit( (last_active < 16 && last_active > 0) ? last_active : 3); 288 return 0; 289 } 290 291 /* Prod the chip without interrupts */ 292 static void macii_poll(void) 293 { 294 unsigned long flags; 295 296 local_irq_save(flags); 297 if (via[IFR] & SR_INT) macii_interrupt(0, NULL); 298 local_irq_restore(flags); 299 } 300 301 /* Reset the bus */ 302 static int macii_reset_bus(void) 303 { 304 static struct adb_request req; 305 306 /* Command = 0, Address = ignored */ 307 adb_request(&req, NULL, 0, 1, ADB_BUSRESET); 308 309 return 0; 310 } 311 312 /* Start sending ADB packet */ 313 static void macii_start(void) 314 { 315 unsigned long flags; 316 struct adb_request *req; 317 318 req = current_req; 319 if (!req) return; 320 321 /* assert macii_state == idle */ 322 if (macii_state != idle) { 323 printk("macii_start: called while driver busy (%p %x %x)!\n", 324 req, macii_state, (uint) via1[B] & (ST_MASK|TREQ)); 325 return; 326 } 327 328 local_irq_save(flags); 329 330 /* 331 * IRQ signaled ?? (means ADB controller wants to send, or might 332 * be end of packet if we were reading) 333 */ 334 #if 0 /* FIXME: This is broke broke broke, for some reason */ 335 if ((via[B] & TREQ) == 0) { 336 printk("macii_start: weird poll stuff. huh?\n"); 337 /* 338 * FIXME - we need to restart this on a timer 339 * or a collision at boot hangs us. 340 * Never set macii_state to idle here, or macii_start 341 * won't be called again from send_request! 342 * (need to re-check other cases ...) 343 */ 344 /* 345 * if the interrupt handler set the need_poll 346 * flag, it's hopefully a SRQ poll or re-Talk 347 * so we try to send here anyway 348 */ 349 if (!need_poll) { 350 if (console_loglevel == 10) 351 printk("macii_start: device busy - retry %p state %d status %x!\n", 352 req, macii_state, 353 (uint) via[B] & (ST_MASK|TREQ)); 354 retry_req = req; 355 /* set ADB status here ? */ 356 local_irq_restore(flags); 357 return; 358 } else { 359 need_poll = 0; 360 } 361 } 362 #endif 363 /* 364 * Another retry pending? (sanity check) 365 */ 366 if (retry_req) { 367 retry_req = NULL; 368 } 369 370 /* Now send it. Be careful though, that first byte of the request */ 371 /* is actually ADB_PACKET; the real data begins at index 1! */ 372 373 /* store command byte */ 374 command_byte = req->data[1]; 375 /* Output mode */ 376 via[ACR] |= SR_OUT; 377 /* Load data */ 378 via[SR] = req->data[1]; 379 /* set ADB state to 'command' */ 380 via[B] = (via[B] & ~ST_MASK) | ST_CMD; 381 382 macii_state = sending; 383 data_index = 2; 384 385 local_irq_restore(flags); 386 } 387 388 /* 389 * The notorious ADB interrupt handler - does all of the protocol handling, 390 * except for starting new send operations. Relies heavily on the ADB 391 * controller sending and receiving data, thereby generating SR interrupts 392 * for us. This means there has to be always activity on the ADB bus, otherwise 393 * the whole process dies and has to be re-kicked by sending TALK requests ... 394 * CUDA-based Macs seem to solve this with the autopoll option, for MacII-type 395 * ADB the problem isn't solved yet (retransmit of the latest active TALK seems 396 * a good choice; either on timeout or on a timer interrupt). 397 * 398 * The basic ADB state machine was left unchanged from the original MacII code 399 * by Alan Cox, which was based on the CUDA driver for PowerMac. 400 * The syntax of the ADB status lines seems to be totally different on MacII, 401 * though. MacII uses the states Command -> Even -> Odd -> Even ->...-> Idle for 402 * sending, and Idle -> Even -> Odd -> Even ->...-> Idle for receiving. Start 403 * and end of a receive packet are signaled by asserting /IRQ on the interrupt 404 * line. Timeouts are signaled by a sequence of 4 0xFF, with /IRQ asserted on 405 * every other byte. SRQ is probably signaled by 3 or more 0xFF tacked on the 406 * end of a packet. (Thanks to Guido Koerber for eavesdropping on the ADB 407 * protocol with a logic analyzer!!) 408 * 409 * Note: As of 21/10/97, the MacII ADB part works including timeout detection 410 * and retransmit (Talk to the last active device). 411 */ 412 static irqreturn_t macii_interrupt(int irq, void *arg) 413 { 414 int x, adbdir; 415 unsigned long flags; 416 struct adb_request *req; 417 418 last_status = status; 419 420 /* prevent races due to SCSI enabling ints */ 421 local_irq_save(flags); 422 423 if (driver_running) { 424 local_irq_restore(flags); 425 return IRQ_NONE; 426 } 427 428 driver_running = 1; 429 430 status = via[B] & (ST_MASK|TREQ); 431 adbdir = via[ACR] & SR_OUT; 432 433 switch (macii_state) { 434 case idle: 435 x = via[SR]; 436 first_byte = x; 437 /* set ADB state = even for first data byte */ 438 via[B] = (via[B] & ~ST_MASK) | ST_EVEN; 439 440 reply_buf[0] = first_byte; /* was command_byte?? */ 441 reply_ptr = reply_buf + 1; 442 reply_len = 1; 443 prefix_len = 1; 444 reading_reply = 0; 445 446 macii_state = reading; 447 break; 448 449 case awaiting_reply: 450 /* handshake etc. for II ?? */ 451 x = via[SR]; 452 first_byte = x; 453 /* set ADB state = even for first data byte */ 454 via[B] = (via[B] & ~ST_MASK) | ST_EVEN; 455 456 current_req->reply[0] = first_byte; 457 reply_ptr = current_req->reply + 1; 458 reply_len = 1; 459 prefix_len = 1; 460 reading_reply = 1; 461 462 macii_state = reading; 463 break; 464 465 case sending: 466 req = current_req; 467 if (data_index >= req->nbytes) { 468 /* print an error message if a listen command has no data */ 469 if (((command_byte & 0x0C) == 0x08) 470 /* && (console_loglevel == 10) */ 471 && (data_index == 2)) 472 printk("MacII ADB: listen command with no data: %x!\n", 473 command_byte); 474 /* reset to shift in */ 475 via[ACR] &= ~SR_OUT; 476 x = via[SR]; 477 /* set ADB state idle - might get SRQ */ 478 via[B] = (via[B] & ~ST_MASK) | ST_IDLE; 479 480 req->sent = 1; 481 482 if (req->reply_expected) { 483 macii_state = awaiting_reply; 484 } else { 485 req->complete = 1; 486 current_req = req->next; 487 if (req->done) (*req->done)(req); 488 macii_state = idle; 489 if (current_req || retry_req) 490 macii_start(); 491 else 492 macii_retransmit((command_byte & 0xF0) >> 4); 493 } 494 } else { 495 via[SR] = req->data[data_index++]; 496 497 if ( (via[B] & ST_MASK) == ST_CMD ) { 498 /* just sent the command byte, set to EVEN */ 499 via[B] = (via[B] & ~ST_MASK) | ST_EVEN; 500 } else { 501 /* invert state bits, toggle ODD/EVEN */ 502 via[B] ^= ST_MASK; 503 } 504 } 505 break; 506 507 case reading: 508 509 /* timeout / SRQ handling for II hw */ 510 if( (first_byte == 0xFF && (reply_len-prefix_len)==2 511 && memcmp(reply_ptr-2,"\xFF\xFF",2)==0) || 512 ((reply_len-prefix_len)==3 513 && memcmp(reply_ptr-3,"\xFF\xFF\xFF",3)==0)) 514 { 515 /* 516 * possible timeout (in fact, most probably a 517 * timeout, since SRQ can't be signaled without 518 * transfer on the bus). 519 * The last three bytes seen were FF, together 520 * with the starting byte (in case we started 521 * on 'idle' or 'awaiting_reply') this probably 522 * makes four. So this is mostl likely #5! 523 * The timeout signal is a pattern 1 0 1 0 0.. 524 * on /INT, meaning we missed it :-( 525 */ 526 x = via[SR]; 527 if (x != 0xFF) printk("MacII ADB: mistaken timeout/SRQ!\n"); 528 529 if ((status & TREQ) == (last_status & TREQ)) { 530 /* Not a timeout. Unsolicited SRQ? weird. */ 531 /* Terminate the SRQ packet and poll */ 532 need_poll = 1; 533 } 534 /* There's no packet to get, so reply is blank */ 535 via[B] ^= ST_MASK; 536 reply_ptr -= (reply_len-prefix_len); 537 reply_len = prefix_len; 538 macii_state = read_done; 539 break; 540 } /* end timeout / SRQ handling for II hw. */ 541 542 if((reply_len-prefix_len)>3 543 && memcmp(reply_ptr-3,"\xFF\xFF\xFF",3)==0) 544 { 545 /* SRQ tacked on data packet */ 546 /* Terminate the packet (SRQ never ends) */ 547 x = via[SR]; 548 macii_state = read_done; 549 reply_len -= 3; 550 reply_ptr -= 3; 551 need_poll = 1; 552 /* need to continue; next byte not seen else */ 553 } else { 554 /* Sanity check */ 555 if (reply_len > 15) reply_len = 0; 556 /* read byte */ 557 x = via[SR]; 558 *reply_ptr = x; 559 reply_ptr++; 560 reply_len++; 561 } 562 /* The usual handshake ... */ 563 564 /* 565 * NetBSD hints that the next to last byte 566 * is sent with IRQ !! 567 * Guido found out it's the last one (0x0), 568 * but IRQ should be asserted already. 569 * Problem with timeout detection: First 570 * transition to /IRQ might be second 571 * byte of timeout packet! 572 * Timeouts are signaled by 4x FF. 573 */ 574 if (((status & TREQ) == 0) && (x == 0x00)) { /* != 0xFF */ 575 /* invert state bits, toggle ODD/EVEN */ 576 via[B] ^= ST_MASK; 577 578 /* adjust packet length */ 579 reply_len--; 580 reply_ptr--; 581 macii_state = read_done; 582 } else { 583 /* not caught: ST_CMD */ 584 /* required for re-entry 'reading'! */ 585 if ((status & ST_MASK) == ST_IDLE) { 586 /* (in)sanity check - set even */ 587 via[B] = (via[B] & ~ST_MASK) | ST_EVEN; 588 } else { 589 /* invert state bits */ 590 via[B] ^= ST_MASK; 591 } 592 } 593 break; 594 595 case read_done: 596 x = via[SR]; 597 if (reading_reply) { 598 req = current_req; 599 req->reply_len = reply_ptr - req->reply; 600 req->complete = 1; 601 current_req = req->next; 602 if (req->done) (*req->done)(req); 603 } else { 604 adb_input(reply_buf, reply_ptr - reply_buf, 0); 605 } 606 607 /* 608 * remember this device ID; it's the latest we got a 609 * reply from! 610 */ 611 last_reply = command_byte; 612 last_active = (command_byte & 0xF0) >> 4; 613 614 /* SRQ seen before, initiate poll now */ 615 if (need_poll) { 616 macii_state = idle; 617 macii_queue_poll(); 618 need_poll = 0; 619 break; 620 } 621 622 /* set ADB state to idle */ 623 via[B] = (via[B] & ~ST_MASK) | ST_IDLE; 624 625 /* /IRQ seen, so the ADB controller has data for us */ 626 if ((via[B] & TREQ) != 0) { 627 macii_state = reading; 628 629 reply_buf[0] = command_byte; 630 reply_ptr = reply_buf + 1; 631 reply_len = 1; 632 prefix_len = 1; 633 reading_reply = 0; 634 } else { 635 /* no IRQ, send next packet or wait */ 636 macii_state = idle; 637 if (current_req) 638 macii_start(); 639 else 640 macii_retransmit(last_active); 641 } 642 break; 643 644 default: 645 break; 646 } 647 /* reset mutex and interrupts */ 648 driver_running = 0; 649 local_irq_restore(flags); 650 return IRQ_HANDLED; 651 } 652