drivers/macintosh/via-macii.c

   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/sched.h>
  23 #include <linux/adb.h>
  24 #include <linux/interrupt.h>
  25 #include <linux/init.h>
  26 #include <asm/macintosh.h>
  27 #include <asm/macints.h>
  28 #include <asm/machw.h>
  29 #include <asm/mac_via.h>
  30 #include <asm/io.h>
  31 #include <asm/system.h>
  32
  33 static volatile unsigned char *via;
  34
  35 /* VIA registers - spaced 0x200 bytes apart */
  36 #define RS              0x200           /* skip between registers */
  37 #define B               0               /* B-side data */
  38 #define A               RS              /* A-side data */
  39 #define DIRB            (2*RS)          /* B-side direction (1=output) */
  40 #define DIRA            (3*RS)          /* A-side direction (1=output) */
  41 #define T1CL            (4*RS)          /* Timer 1 ctr/latch (low 8 bits) */
  42 #define T1CH            (5*RS)          /* Timer 1 counter (high 8 bits) */
  43 #define T1LL            (6*RS)          /* Timer 1 latch (low 8 bits) */
  44 #define T1LH            (7*RS)          /* Timer 1 latch (high 8 bits) */
  45 #define T2CL            (8*RS)          /* Timer 2 ctr/latch (low 8 bits) */
  46 #define T2CH            (9*RS)          /* Timer 2 counter (high 8 bits) */
  47 #define SR              (10*RS)         /* Shift register */
  48 #define ACR             (11*RS)         /* Auxiliary control register */
  49 #define PCR             (12*RS)         /* Peripheral control register */
  50 #define IFR             (13*RS)         /* Interrupt flag register */
  51 #define IER             (14*RS)         /* Interrupt enable register */
  52 #define ANH             (15*RS)         /* A-side data, no handshake */
  53
  54 /* Bits in B data register: all active low */
  55 #define TREQ            0x08            /* Transfer request (input) */
  56 #define TACK            0x10            /* Transfer acknowledge (output) */
  57 #define TIP             0x20            /* Transfer in progress (output) */
  58 #define ST_MASK         0x30            /* mask for selecting ADB state bits */
  59
  60 /* Bits in ACR */
  61 #define SR_CTRL         0x1c            /* Shift register control bits */
  62 #define SR_EXT          0x0c            /* Shift on external clock */
  63 #define SR_OUT          0x10            /* Shift out if 1 */
  64
  65 /* Bits in IFR and IER */
  66 #define IER_SET         0x80            /* set bits in IER */
  67 #define IER_CLR         0               /* clear bits in IER */
  68 #define SR_INT          0x04            /* Shift register full/empty */
  69 #define SR_DATA         0x08            /* Shift register data */
  70 #define SR_CLOCK        0x10            /* Shift register clock */
  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 static int  macii_init_via(void);
  79 static void macii_start(void);
  80 static irqreturn_t macii_interrupt(int irq, void *arg, struct pt_regs *regs);
  81 static void macii_retransmit(int);
  82 static void macii_queue_poll(void);
  83
  84 static int macii_probe(void);
  85 static int macii_init(void);
  86 static int macii_send_request(struct adb_request *req, int sync);
  87 static int macii_write(struct adb_request *req);
  88 static int macii_autopoll(int devs);
  89 static void macii_poll(void);
  90 static int macii_reset_bus(void);
  91
  92 struct adb_driver via_macii_driver = {
  93         "Mac II",
  94         macii_probe,
  95         macii_init,
  96         macii_send_request,
  97         macii_autopoll,
  98         macii_poll,
  99         macii_reset_bus
 100 };
 101
 102 static enum macii_state {
 103         idle,
 104         sending,
 105         reading,
 106         read_done,
 107         awaiting_reply
 108 } macii_state;
 109
 110 static int need_poll    = 0;
 111 static int command_byte = 0;
 112 static int last_reply   = 0;
 113 static int last_active  = 0;
 114
 115 static struct adb_request *current_req;
 116 static struct adb_request *last_req;
 117 static struct adb_request *retry_req;
 118 static unsigned char reply_buf[16];
 119 static unsigned char *reply_ptr;
 120 static int reply_len;
 121 static int reading_reply;
 122 static int data_index;
 123 static int first_byte;
 124 static int prefix_len;
 125 static int status = ST_IDLE|TREQ;
 126 static int last_status;
 127 static int driver_running = 0;
 128
 129 /* debug level 10 required for ADB logging (should be && debug_adb, ideally) */
 130
 131 /* Check for MacII style ADB */
 132 static int macii_probe(void)
 133 {
 134         if (macintosh_config->adb_type != MAC_ADB_II) return -ENODEV;
 135
 136         via = via1;
 137
 138         printk("adb: Mac II ADB Driver v1.0 for Unified ADB\n");
 139         return 0;
 140 }
 141
 142 /* Initialize the driver */
 143 int macii_init(void)
 144 {
 145         unsigned long flags;
 146         int err;
 147
 148         local_irq_save(flags);
 149
 150         err = macii_init_via();
 151         if (err) return err;
 152
 153         err = request_irq(IRQ_MAC_ADB, macii_interrupt, IRQ_FLG_LOCK, "ADB",
 154                           macii_interrupt);
 155         if (err) return err;
 156
 157         macii_state = idle;
 158         local_irq_restore(flags);
 159         return 0;
 160 }
 161
 162 /* initialize the hardware */
 163 static int macii_init_via(void)
 164 {
 165         unsigned char x;
 166
 167         /* Set the lines up. We want TREQ as input TACK|TIP as output */
 168         via[DIRB] = (via[DIRB] | TACK | TIP) & ~TREQ;
 169
 170         /* Set up state: idle */
 171         via[B] |= ST_IDLE;
 172         last_status = via[B] & (ST_MASK|TREQ);
 173
 174         /* Shift register on input */
 175         via[ACR] = (via[ACR] & ~SR_CTRL) | SR_EXT;
 176
 177         /* Wipe any pending data and int */
 178         x = via[SR];
 179
 180         return 0;
 181 }
 182
 183 /* Send an ADB poll (Talk Register 0 command, tagged on the front of the request queue) */
 184 static void macii_queue_poll(void)
 185 {
 186         static int device = 0;
 187         static int in_poll=0;
 188         static struct adb_request req;
 189         unsigned long flags;
 190
 191         if (in_poll) printk("macii_queue_poll: double poll!\n");
 192
 193         in_poll++;
 194         if (++device > 15) device = 1;
 195
 196         adb_request(&req, NULL, ADBREQ_REPLY|ADBREQ_NOSEND, 1,
 197                     ADB_READREG(device, 0));
 198
 199         local_irq_save(flags);
 200
 201         req.next = current_req;
 202         current_req = &req;
 203
 204         local_irq_restore(flags);
 205         macii_start();
 206         in_poll--;
 207 }
 208
 209 /* Send an ADB retransmit (Talk, appended to the request queue) */
 210 static void macii_retransmit(int device)
 211 {
 212         static int in_retransmit = 0;
 213         static struct adb_request rt;
 214         unsigned long flags;
 215
 216         if (in_retransmit) printk("macii_retransmit: double retransmit!\n");
 217
 218         in_retransmit++;
 219
 220         adb_request(&rt, NULL, ADBREQ_REPLY|ADBREQ_NOSEND, 1,
 221                     ADB_READREG(device, 0));
 222
 223         local_irq_save(flags);
 224
 225         if (current_req != NULL) {
 226                 last_req->next = &rt;
 227                 last_req = &rt;
 228         } else {
 229                 current_req = &rt;
 230                 last_req = &rt;
 231         }
 232
 233         if (macii_state == idle) macii_start();
 234
 235         local_irq_restore(flags);
 236         in_retransmit--;
 237 }
 238
 239 /* Send an ADB request; if sync, poll out the reply 'till it's done */
 240 static int macii_send_request(struct adb_request *req, int sync)
 241 {
 242         int i;
 243
 244         i = macii_write(req);
 245         if (i) return i;
 246
 247         if (sync) {
 248                 while (!req->complete) macii_poll();
 249         }
 250         return 0;
 251 }
 252
 253 /* Send an ADB request */
 254 static int macii_write(struct adb_request *req)
 255 {
 256         unsigned long flags;
 257
 258         if (req->nbytes < 2 || req->data[0] != ADB_PACKET || req->nbytes > 15) {
 259                 req->complete = 1;
 260                 return -EINVAL;
 261         }
 262
 263         req->next = NULL;
 264         req->sent = 0;
 265         req->complete = 0;
 266         req->reply_len = 0;
 267
 268         local_irq_save(flags);
 269
 270         if (current_req != NULL) {
 271                 last_req->next = req;
 272                 last_req = req;
 273         } else {
 274                 current_req = req;
 275                 last_req = req;
 276                 if (macii_state == idle) macii_start();
 277         }
 278
 279         local_irq_restore(flags);
 280         return 0;
 281 }
 282
 283 /* Start auto-polling */
 284 static int macii_autopoll(int devs)
 285 {
 286         /* Just ping a random default address */
 287         if (!(current_req || retry_req))
 288                 macii_retransmit( (last_active < 16 && last_active > 0) ? last_active : 3);
 289         return 0;
 290 }
 291
 292 /* Prod the chip without interrupts */
 293 static void macii_poll(void)
 294 {
 295         unsigned long flags;
 296
 297         local_irq_save(flags);
 298         if (via[IFR] & SR_INT) macii_interrupt(0, NULL, NULL);
 299         local_irq_restore(flags);
 300 }
 301
 302 /* Reset the bus */
 303 static int macii_reset_bus(void)
 304 {
 305         static struct adb_request req;
 306
 307         /* Command = 0, Address = ignored */
 308         adb_request(&req, NULL, 0, 1, ADB_BUSRESET);
 309
 310         return 0;
 311 }
 312
 313 /* Start sending ADB packet */
 314 static void macii_start(void)
 315 {
 316         unsigned long flags;
 317         struct adb_request *req;
 318
 319         req = current_req;
 320         if (!req) return;
 321
 322         /* assert macii_state == idle */
 323         if (macii_state != idle) {
 324                 printk("macii_start: called while driver busy (%p %x %x)!\n",
 325                         req, macii_state, (uint) via1[B] & (ST_MASK|TREQ));
 326                 return;
 327         }
 328
 329         local_irq_save(flags);
 330
 331         /*
 332          * IRQ signaled ?? (means ADB controller wants to send, or might
 333          * be end of packet if we were reading)
 334          */
 335 #if 0 /* FIXME: This is broke broke broke, for some reason */
 336         if ((via[B] & TREQ) == 0) {
 337                 printk("macii_start: weird poll stuff. huh?\n");
 338                 /*
 339                  *      FIXME - we need to restart this on a timer
 340                  *      or a collision at boot hangs us.
 341                  *      Never set macii_state to idle here, or macii_start
 342                  *      won't be called again from send_request!
 343                  *      (need to re-check other cases ...)
 344                  */
 345                 /*
 346                  * if the interrupt handler set the need_poll
 347                  * flag, it's hopefully a SRQ poll or re-Talk
 348                  * so we try to send here anyway
 349                  */
 350                 if (!need_poll) {
 351                         if (console_loglevel == 10)
 352                                 printk("macii_start: device busy - retry %p state %d status %x!\n",
 353                                         req, macii_state,
 354                                         (uint) via[B] & (ST_MASK|TREQ));
 355                         retry_req = req;
 356                         /* set ADB status here ? */
 357                         local_irq_restore(flags);
 358                         return;
 359                 } else {
 360                         need_poll = 0;
 361                 }
 362         }
 363 #endif
 364         /*
 365          * Another retry pending? (sanity check)
 366          */
 367         if (retry_req) {
 368                 retry_req = NULL;
 369         }
 370
 371         /* Now send it. Be careful though, that first byte of the request */
 372         /* is actually ADB_PACKET; the real data begins at index 1!       */
 373
 374         /* store command byte */
 375         command_byte = req->data[1];
 376         /* Output mode */
 377         via[ACR] |= SR_OUT;
 378         /* Load data */
 379         via[SR] = req->data[1];
 380         /* set ADB state to 'command' */
 381         via[B] = (via[B] & ~ST_MASK) | ST_CMD;
 382
 383         macii_state = sending;
 384         data_index = 2;
 385
 386         local_irq_restore(flags);
 387 }
 388
 389 /*
 390  * The notorious ADB interrupt handler - does all of the protocol handling,
 391  * except for starting new send operations. Relies heavily on the ADB
 392  * controller sending and receiving data, thereby generating SR interrupts
 393  * for us. This means there has to be always activity on the ADB bus, otherwise
 394  * the whole process dies and has to be re-kicked by sending TALK requests ...
 395  * CUDA-based Macs seem to solve this with the autopoll option, for MacII-type
 396  * ADB the problem isn't solved yet (retransmit of the latest active TALK seems
 397  * a good choice; either on timeout or on a timer interrupt).
 398  *
 399  * The basic ADB state machine was left unchanged from the original MacII code
 400  * by Alan Cox, which was based on the CUDA driver for PowerMac.
 401  * The syntax of the ADB status lines seems to be totally different on MacII,
 402  * though. MacII uses the states Command -> Even -> Odd -> Even ->...-> Idle for
 403  * sending, and Idle -> Even -> Odd -> Even ->...-> Idle for receiving. Start
 404  * and end of a receive packet are signaled by asserting /IRQ on the interrupt
 405  * line. Timeouts are signaled by a sequence of 4 0xFF, with /IRQ asserted on
 406  * every other byte. SRQ is probably signaled by 3 or more 0xFF tacked on the
 407  * end of a packet. (Thanks to Guido Koerber for eavesdropping on the ADB
 408  * protocol with a logic analyzer!!)
 409  *
 410  * Note: As of 21/10/97, the MacII ADB part works including timeout detection
 411  * and retransmit (Talk to the last active device).
 412  */
 413 static irqreturn_t macii_interrupt(int irq, void *arg, struct pt_regs *regs)
 414 {
 415         int x, adbdir;
 416         unsigned long flags;
 417         struct adb_request *req;
 418
 419         last_status = status;
 420
 421         /* prevent races due to SCSI enabling ints */
 422         local_irq_save(flags);
 423
 424         if (driver_running) {
 425                 local_irq_restore(flags);
 426                 return IRQ_NONE;
 427         }
 428
 429         driver_running = 1;
 430
 431         status = via[B] & (ST_MASK|TREQ);
 432         adbdir = via[ACR] & SR_OUT;
 433
 434         switch (macii_state) {
 435                 case idle:
 436                         x = via[SR];
 437                         first_byte = x;
 438                         /* set ADB state = even for first data byte */
 439                         via[B] = (via[B] & ~ST_MASK) | ST_EVEN;
 440
 441                         reply_buf[0] = first_byte; /* was command_byte?? */
 442                         reply_ptr = reply_buf + 1;
 443                         reply_len = 1;
 444                         prefix_len = 1;
 445                         reading_reply = 0;
 446
 447                         macii_state = reading;
 448                         break;
 449
 450                 case awaiting_reply:
 451                         /* handshake etc. for II ?? */
 452                         x = via[SR];
 453                         first_byte = x;
 454                         /* set ADB state = even for first data byte */
 455                         via[B] = (via[B] & ~ST_MASK) | ST_EVEN;
 456
 457                         current_req->reply[0] = first_byte;
 458                         reply_ptr = current_req->reply + 1;
 459                         reply_len = 1;
 460                         prefix_len = 1;
 461                         reading_reply = 1;
 462
 463                         macii_state = reading;
 464                         break;
 465
 466                 case sending:
 467                         req = current_req;
 468                         if (data_index >= req->nbytes) {
 469                                 /* print an error message if a listen command has no data */
 470                                 if (((command_byte & 0x0C) == 0x08)
 471                                  /* && (console_loglevel == 10) */
 472                                     && (data_index == 2))
 473                                         printk("MacII ADB: listen command with no data: %x!\n",
 474                                                 command_byte);
 475                                 /* reset to shift in */
 476                                 via[ACR] &= ~SR_OUT;
 477                                 x = via[SR];
 478                                 /* set ADB state idle - might get SRQ */
 479                                 via[B] = (via[B] & ~ST_MASK) | ST_IDLE;
 480
 481                                 req->sent = 1;
 482
 483                                 if (req->reply_expected) {
 484                                         macii_state = awaiting_reply;
 485                                 } else {
 486                                         req->complete = 1;
 487                                         current_req = req->next;
 488                                         if (req->done) (*req->done)(req);
 489                                         macii_state = idle;
 490                                         if (current_req || retry_req)
 491                                                 macii_start();
 492                                         else
 493                                                 macii_retransmit((command_byte & 0xF0) >> 4);
 494                                 }
 495                         } else {
 496                                 via[SR] = req->data[data_index++];
 497
 498                                 if ( (via[B] & ST_MASK) == ST_CMD ) {
 499                                         /* just sent the command byte, set to EVEN */
 500                                         via[B] = (via[B] & ~ST_MASK) | ST_EVEN;
 501                                 } else {
 502                                         /* invert state bits, toggle ODD/EVEN */
 503                                         via[B] ^= ST_MASK;
 504                                 }
 505                         }
 506                         break;
 507
 508                 case reading:
 509
 510                         /* timeout / SRQ handling for II hw */
 511                         if( (first_byte == 0xFF && (reply_len-prefix_len)==2
 512                              && memcmp(reply_ptr-2,"\xFF\xFF",2)==0) ||
 513                             ((reply_len-prefix_len)==3
 514                              && memcmp(reply_ptr-3,"\xFF\xFF\xFF",3)==0))
 515                         {
 516                                 /*
 517                                  * possible timeout (in fact, most probably a
 518                                  * timeout, since SRQ can't be signaled without
 519                                  * transfer on the bus).
 520                                  * The last three bytes seen were FF, together
 521                                  * with the starting byte (in case we started
 522                                  * on 'idle' or 'awaiting_reply') this probably
 523                                  * makes four. So this is mostl likely #5!
 524                                  * The timeout signal is a pattern 1 0 1 0 0..
 525                                  * on /INT, meaning we missed it :-(
 526                                  */
 527                                 x = via[SR];
 528                                 if (x != 0xFF) printk("MacII ADB: mistaken timeout/SRQ!\n");
 529
 530                                 if ((status & TREQ) == (last_status & TREQ)) {
 531                                         /* Not a timeout. Unsolicited SRQ? weird. */
 532                                         /* Terminate the SRQ packet and poll */
 533                                         need_poll = 1;
 534                                 }
 535                                 /* There's no packet to get, so reply is blank */
 536                                 via[B] ^= ST_MASK;
 537                                 reply_ptr -= (reply_len-prefix_len);
 538                                 reply_len = prefix_len;
 539                                 macii_state = read_done;
 540                                 break;
 541                         } /* end timeout / SRQ handling for II hw. */
 542
 543                         if((reply_len-prefix_len)>3
 544                                 && memcmp(reply_ptr-3,"\xFF\xFF\xFF",3)==0)
 545                         {
 546                                 /* SRQ tacked on data packet */
 547                                 /* Terminate the packet (SRQ never ends) */
 548                                 x = via[SR];
 549                                 macii_state = read_done;
 550                                 reply_len -= 3;
 551                                 reply_ptr -= 3;
 552                                 need_poll = 1;
 553                                 /* need to continue; next byte not seen else */
 554                         } else {
 555                                 /* Sanity check */
 556                                 if (reply_len > 15) reply_len = 0;
 557                                 /* read byte */
 558                                 x = via[SR];
 559                                 *reply_ptr = x;
 560                                 reply_ptr++;
 561                                 reply_len++;
 562                         }
 563                         /* The usual handshake ... */
 564
 565                         /*
 566                          * NetBSD hints that the next to last byte
 567                          * is sent with IRQ !!
 568                          * Guido found out it's the last one (0x0),
 569                          * but IRQ should be asserted already.
 570                          * Problem with timeout detection: First
 571                          * transition to /IRQ might be second
 572                          * byte of timeout packet!
 573                          * Timeouts are signaled by 4x FF.
 574                          */
 575                         if (((status & TREQ) == 0) && (x == 0x00)) { /* != 0xFF */
 576                                 /* invert state bits, toggle ODD/EVEN */
 577                                 via[B] ^= ST_MASK;
 578
 579                                 /* adjust packet length */
 580                                 reply_len--;
 581                                 reply_ptr--;
 582                                 macii_state = read_done;
 583                         } else {
 584                                 /* not caught: ST_CMD */
 585                                 /* required for re-entry 'reading'! */
 586                                 if ((status & ST_MASK) == ST_IDLE) {
 587                                         /* (in)sanity check - set even */
 588                                         via[B] = (via[B] & ~ST_MASK) | ST_EVEN;
 589                                 } else {
 590                                         /* invert state bits */
 591                                         via[B] ^= ST_MASK;
 592                                 }
 593                         }
 594                         break;
 595
 596                 case read_done:
 597                         x = via[SR];
 598                         if (reading_reply) {
 599                                 req = current_req;
 600                                 req->reply_len = reply_ptr - req->reply;
 601                                 req->complete = 1;
 602                                 current_req = req->next;
 603                                 if (req->done) (*req->done)(req);
 604                         } else {
 605                                 adb_input(reply_buf, reply_ptr - reply_buf,
 606                                           regs, 0);
 607                         }
 608
 609                         /*
 610                          * remember this device ID; it's the latest we got a
 611                          * reply from!
 612                          */
 613                         last_reply = command_byte;
 614                         last_active = (command_byte & 0xF0) >> 4;
 615
 616                         /* SRQ seen before, initiate poll now */
 617                         if (need_poll) {
 618                                 macii_state = idle;
 619                                 macii_queue_poll();
 620                                 need_poll = 0;
 621                                 break;
 622                         }
 623
 624                         /* set ADB state to idle */
 625                         via[B] = (via[B] & ~ST_MASK) | ST_IDLE;
 626
 627                         /* /IRQ seen, so the ADB controller has data for us */
 628                         if ((via[B] & TREQ) != 0) {
 629                                 macii_state = reading;
 630
 631                                 reply_buf[0] = command_byte;
 632                                 reply_ptr = reply_buf + 1;
 633                                 reply_len = 1;
 634                                 prefix_len = 1;
 635                                 reading_reply = 0;
 636                         } else {
 637                                 /* no IRQ, send next packet or wait */
 638                                 macii_state = idle;
 639                                 if (current_req)
 640                                         macii_start();
 641                                 else
 642                                         macii_retransmit(last_active);
 643                         }
 644                         break;
 645
 646                 default:
 647                 break;
 648         }
 649         /* reset mutex and interrupts */
 650         driver_running = 0;
 651         local_irq_restore(flags);
 652         return IRQ_HANDLED;
 653 }