drivers/macintosh/via-cuda.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Device driver for the Cuda and Egret system controllers found on PowerMacs
   4  * and 68k Macs.
   5  *
   6  * The Cuda or Egret is a 6805 microcontroller interfaced to the 6522 VIA.
   7  * This MCU controls system power, Parameter RAM, Real Time Clock and the
   8  * Apple Desktop Bus (ADB) that connects to the keyboard and mouse.
   9  *
  10  * Copyright (C) 1996 Paul Mackerras.
  11  */
  12 #include <linux/stdarg.h>
  13 #include <linux/types.h>
  14 #include <linux/errno.h>
  15 #include <linux/kernel.h>
  16 #include <linux/delay.h>
  17 #include <linux/adb.h>
  18 #include <linux/cuda.h>
  19 #include <linux/spinlock.h>
  20 #include <linux/interrupt.h>
  21 #include <linux/of_address.h>
  22 #include <linux/of_irq.h>
  23
  24 #ifdef CONFIG_PPC
  25 #include <asm/machdep.h>
  26 #include <asm/pmac_feature.h>
  27 #else
  28 #include <asm/macintosh.h>
  29 #include <asm/macints.h>
  30 #include <asm/mac_via.h>
  31 #endif
  32 #include <asm/io.h>
  33 #include <linux/init.h>
  34
  35 static volatile unsigned char __iomem *via;
  36 static DEFINE_SPINLOCK(cuda_lock);
  37
  38 /* VIA registers - spaced 0x200 bytes apart */
  39 #define RS              0x200           /* skip between registers */
  40 #define B               0               /* B-side data */
  41 #define A               RS              /* A-side data */
  42 #define DIRB            (2*RS)          /* B-side direction (1=output) */
  43 #define DIRA            (3*RS)          /* A-side direction (1=output) */
  44 #define T1CL            (4*RS)          /* Timer 1 ctr/latch (low 8 bits) */
  45 #define T1CH            (5*RS)          /* Timer 1 counter (high 8 bits) */
  46 #define T1LL            (6*RS)          /* Timer 1 latch (low 8 bits) */
  47 #define T1LH            (7*RS)          /* Timer 1 latch (high 8 bits) */
  48 #define T2CL            (8*RS)          /* Timer 2 ctr/latch (low 8 bits) */
  49 #define T2CH            (9*RS)          /* Timer 2 counter (high 8 bits) */
  50 #define SR              (10*RS)         /* Shift register */
  51 #define ACR             (11*RS)         /* Auxiliary control register */
  52 #define PCR             (12*RS)         /* Peripheral control register */
  53 #define IFR             (13*RS)         /* Interrupt flag register */
  54 #define IER             (14*RS)         /* Interrupt enable register */
  55 #define ANH             (15*RS)         /* A-side data, no handshake */
  56
  57 /*
  58  * When the Cuda design replaced the Egret, some signal names and
  59  * logic sense changed. They all serve the same purposes, however.
  60  *
  61  *   VIA pin       |  Egret pin
  62  * ----------------+------------------------------------------
  63  *   PB3 (input)   |  Transceiver session   (active low)
  64  *   PB4 (output)  |  VIA full              (active high)
  65  *   PB5 (output)  |  System session        (active high)
  66  *
  67  *   VIA pin       |  Cuda pin
  68  * ----------------+------------------------------------------
  69  *   PB3 (input)   |  Transfer request      (active low)
  70  *   PB4 (output)  |  Byte acknowledge      (active low)
  71  *   PB5 (output)  |  Transfer in progress  (active low)
  72  */
  73
  74 /* Bits in Port B data register */
  75 #define TREQ            0x08            /* Transfer request */
  76 #define TACK            0x10            /* Transfer acknowledge */
  77 #define TIP             0x20            /* Transfer in progress */
  78
  79 /* Bits in ACR */
  80 #define SR_CTRL         0x1c            /* Shift register control bits */
  81 #define SR_EXT          0x0c            /* Shift on external clock */
  82 #define SR_OUT          0x10            /* Shift out if 1 */
  83
  84 /* Bits in IFR and IER */
  85 #define IER_SET         0x80            /* set bits in IER */
  86 #define IER_CLR         0               /* clear bits in IER */
  87 #define SR_INT          0x04            /* Shift register full/empty */
  88
  89 /* Duration of byte acknowledgement pulse (us) */
  90 #define EGRET_TACK_ASSERTED_DELAY       300
  91 #define EGRET_TACK_NEGATED_DELAY        400
  92
  93 /* Interval from interrupt to start of session (us) */
  94 #define EGRET_SESSION_DELAY             450
  95
  96 #ifdef CONFIG_PPC
  97 #define mcu_is_egret    false
  98 #else
  99 static bool mcu_is_egret;
 100 #endif
 101
 102 static inline bool TREQ_asserted(u8 portb)
 103 {
 104         return !(portb & TREQ);
 105 }
 106
 107 static inline void assert_TIP(void)
 108 {
 109         if (mcu_is_egret) {
 110                 udelay(EGRET_SESSION_DELAY);
 111                 out_8(&via[B], in_8(&via[B]) | TIP);
 112         } else
 113                 out_8(&via[B], in_8(&via[B]) & ~TIP);
 114 }
 115
 116 static inline void assert_TIP_and_TACK(void)
 117 {
 118         if (mcu_is_egret) {
 119                 udelay(EGRET_SESSION_DELAY);
 120                 out_8(&via[B], in_8(&via[B]) | TIP | TACK);
 121         } else
 122                 out_8(&via[B], in_8(&via[B]) & ~(TIP | TACK));
 123 }
 124
 125 static inline void assert_TACK(void)
 126 {
 127         if (mcu_is_egret) {
 128                 udelay(EGRET_TACK_NEGATED_DELAY);
 129                 out_8(&via[B], in_8(&via[B]) | TACK);
 130         } else
 131                 out_8(&via[B], in_8(&via[B]) & ~TACK);
 132 }
 133
 134 static inline void toggle_TACK(void)
 135 {
 136         out_8(&via[B], in_8(&via[B]) ^ TACK);
 137 }
 138
 139 static inline void negate_TACK(void)
 140 {
 141         if (mcu_is_egret) {
 142                 udelay(EGRET_TACK_ASSERTED_DELAY);
 143                 out_8(&via[B], in_8(&via[B]) & ~TACK);
 144         } else
 145                 out_8(&via[B], in_8(&via[B]) | TACK);
 146 }
 147
 148 static inline void negate_TIP_and_TACK(void)
 149 {
 150         if (mcu_is_egret) {
 151                 udelay(EGRET_TACK_ASSERTED_DELAY);
 152                 out_8(&via[B], in_8(&via[B]) & ~(TIP | TACK));
 153         } else
 154                 out_8(&via[B], in_8(&via[B]) | TIP | TACK);
 155 }
 156
 157 static enum cuda_state {
 158     idle,
 159     sent_first_byte,
 160     sending,
 161     reading,
 162     read_done,
 163     awaiting_reply
 164 } cuda_state;
 165
 166 static struct adb_request *current_req;
 167 static struct adb_request *last_req;
 168 static unsigned char cuda_rbuf[16];
 169 static unsigned char *reply_ptr;
 170 static int reading_reply;
 171 static int data_index;
 172 static int cuda_irq;
 173 #ifdef CONFIG_PPC
 174 static struct device_node *vias;
 175 #endif
 176 static int cuda_fully_inited;
 177
 178 #ifdef CONFIG_ADB
 179 static int cuda_probe(void);
 180 static int cuda_send_request(struct adb_request *req, int sync);
 181 static int cuda_adb_autopoll(int devs);
 182 static int cuda_reset_adb_bus(void);
 183 #endif /* CONFIG_ADB */
 184
 185 static int cuda_init_via(void);
 186 static void cuda_start(void);
 187 static irqreturn_t cuda_interrupt(int irq, void *arg);
 188 static void cuda_input(unsigned char *buf, int nb);
 189 void cuda_poll(void);
 190 static int cuda_write(struct adb_request *req);
 191
 192 int cuda_request(struct adb_request *req,
 193                  void (*done)(struct adb_request *), int nbytes, ...);
 194
 195 #ifdef CONFIG_ADB
 196 struct adb_driver via_cuda_driver = {
 197         .name         = "CUDA",
 198         .probe        = cuda_probe,
 199         .send_request = cuda_send_request,
 200         .autopoll     = cuda_adb_autopoll,
 201         .poll         = cuda_poll,
 202         .reset_bus    = cuda_reset_adb_bus,
 203 };
 204 #endif /* CONFIG_ADB */
 205
 206 #ifdef CONFIG_MAC
 207 int __init find_via_cuda(void)
 208 {
 209     struct adb_request req;
 210     int err;
 211
 212     if (macintosh_config->adb_type != MAC_ADB_CUDA &&
 213         macintosh_config->adb_type != MAC_ADB_EGRET)
 214         return 0;
 215
 216     via = via1;
 217     cuda_state = idle;
 218     mcu_is_egret = macintosh_config->adb_type == MAC_ADB_EGRET;
 219
 220     err = cuda_init_via();
 221     if (err) {
 222         printk(KERN_ERR "cuda_init_via() failed\n");
 223         via = NULL;
 224         return 0;
 225     }
 226
 227     /* enable autopoll */
 228     cuda_request(&req, NULL, 3, CUDA_PACKET, CUDA_AUTOPOLL, 1);
 229     while (!req.complete)
 230         cuda_poll();
 231
 232     return 1;
 233 }
 234 #else
 235 int __init find_via_cuda(void)
 236 {
 237     struct adb_request req;
 238     struct resource res;
 239     int err;
 240
 241     if (vias)
 242         return 1;
 243     vias = of_find_node_by_name(NULL, "via-cuda");
 244     if (!vias)
 245         return 0;
 246
 247     err = of_address_to_resource(vias, 0, &res);
 248     if (err) {
 249             printk(KERN_ERR "via-cuda: Error getting \"reg\" property !\n");
 250             goto fail;
 251     }
 252     via = ioremap(res.start, 0x2000);
 253     if (via == NULL) {
 254             printk(KERN_ERR "via-cuda: Can't map address !\n");
 255             goto fail;
 256     }
 257
 258     cuda_state = idle;
 259     sys_ctrler = SYS_CTRLER_CUDA;
 260
 261     err = cuda_init_via();
 262     if (err) {
 263         printk(KERN_ERR "cuda_init_via() failed\n");
 264         via = NULL;
 265         return 0;
 266     }
 267
 268     /* Clear and enable interrupts, but only on PPC. On 68K it's done  */
 269     /* for us by the main VIA driver in arch/m68k/mac/via.c        */
 270
 271     out_8(&via[IFR], 0x7f);     /* clear interrupts by writing 1s */
 272     out_8(&via[IER], IER_SET|SR_INT); /* enable interrupt from SR */
 273
 274     /* enable autopoll */
 275     cuda_request(&req, NULL, 3, CUDA_PACKET, CUDA_AUTOPOLL, 1);
 276     while (!req.complete)
 277         cuda_poll();
 278
 279     return 1;
 280
 281  fail:
 282     of_node_put(vias);
 283     vias = NULL;
 284     return 0;
 285 }
 286 #endif /* !defined CONFIG_MAC */
 287
 288 static int __init via_cuda_start(void)
 289 {
 290     if (via == NULL)
 291         return -ENODEV;
 292
 293 #ifdef CONFIG_MAC
 294     cuda_irq = IRQ_MAC_ADB;
 295 #else
 296     cuda_irq = irq_of_parse_and_map(vias, 0);
 297     if (!cuda_irq) {
 298         printk(KERN_ERR "via-cuda: can't map interrupts for %pOF\n",
 299                vias);
 300         return -ENODEV;
 301     }
 302 #endif
 303
 304     if (request_irq(cuda_irq, cuda_interrupt, 0, "ADB", cuda_interrupt)) {
 305         printk(KERN_ERR "via-cuda: can't request irq %d\n", cuda_irq);
 306         return -EAGAIN;
 307     }
 308
 309     pr_info("Macintosh Cuda and Egret driver.\n");
 310
 311     cuda_fully_inited = 1;
 312     return 0;
 313 }
 314
 315 device_initcall(via_cuda_start);
 316
 317 #ifdef CONFIG_ADB
 318 static int
 319 cuda_probe(void)
 320 {
 321 #ifdef CONFIG_PPC
 322     if (sys_ctrler != SYS_CTRLER_CUDA)
 323         return -ENODEV;
 324 #else
 325     if (macintosh_config->adb_type != MAC_ADB_CUDA &&
 326         macintosh_config->adb_type != MAC_ADB_EGRET)
 327         return -ENODEV;
 328 #endif
 329     if (via == NULL)
 330         return -ENODEV;
 331     return 0;
 332 }
 333 #endif /* CONFIG_ADB */
 334
 335 static int __init sync_egret(void)
 336 {
 337         if (TREQ_asserted(in_8(&via[B]))) {
 338                 /* Complete the inbound transfer */
 339                 assert_TIP_and_TACK();
 340                 while (1) {
 341                         negate_TACK();
 342                         mdelay(1);
 343                         (void)in_8(&via[SR]);
 344                         assert_TACK();
 345                         if (!TREQ_asserted(in_8(&via[B])))
 346                                 break;
 347                 }
 348                 negate_TIP_and_TACK();
 349         } else if (in_8(&via[B]) & TIP) {
 350                 /* Terminate the outbound transfer */
 351                 negate_TACK();
 352                 assert_TACK();
 353                 mdelay(1);
 354                 negate_TIP_and_TACK();
 355         }
 356         /* Clear shift register interrupt */
 357         if (in_8(&via[IFR]) & SR_INT)
 358                 (void)in_8(&via[SR]);
 359         return 0;
 360 }
 361
 362 #define WAIT_FOR(cond, what)                                    \
 363     do {                                                        \
 364         int x;                                                  \
 365         for (x = 1000; !(cond); --x) {                          \
 366             if (x == 0) {                                       \
 367                 pr_err("Timeout waiting for " what "\n");       \
 368                 return -ENXIO;                                  \
 369             }                                                   \
 370             udelay(100);                                        \
 371         }                                                       \
 372     } while (0)
 373
 374 static int
 375 __init cuda_init_via(void)
 376 {
 377 #ifdef CONFIG_PPC
 378     out_8(&via[IER], 0x7f);                                     /* disable interrupts from VIA */
 379     (void)in_8(&via[IER]);
 380 #else
 381     out_8(&via[IER], SR_INT);                                   /* disable SR interrupt from VIA */
 382 #endif
 383
 384     out_8(&via[DIRB], (in_8(&via[DIRB]) | TACK | TIP) & ~TREQ); /* TACK & TIP out */
 385     out_8(&via[ACR], (in_8(&via[ACR]) & ~SR_CTRL) | SR_EXT);    /* SR data in */
 386     (void)in_8(&via[SR]);                                       /* clear any left-over data */
 387
 388     if (mcu_is_egret)
 389         return sync_egret();
 390
 391     negate_TIP_and_TACK();
 392
 393     /* delay 4ms and then clear any pending interrupt */
 394     mdelay(4);
 395     (void)in_8(&via[SR]);
 396     out_8(&via[IFR], SR_INT);
 397
 398     /* sync with the CUDA - assert TACK without TIP */
 399     assert_TACK();
 400
 401     /* wait for the CUDA to assert TREQ in response */
 402     WAIT_FOR(TREQ_asserted(in_8(&via[B])), "CUDA response to sync");
 403
 404     /* wait for the interrupt and then clear it */
 405     WAIT_FOR(in_8(&via[IFR]) & SR_INT, "CUDA response to sync (2)");
 406     (void)in_8(&via[SR]);
 407     out_8(&via[IFR], SR_INT);
 408
 409     /* finish the sync by negating TACK */
 410     negate_TACK();
 411
 412     /* wait for the CUDA to negate TREQ and the corresponding interrupt */
 413     WAIT_FOR(!TREQ_asserted(in_8(&via[B])), "CUDA response to sync (3)");
 414     WAIT_FOR(in_8(&via[IFR]) & SR_INT, "CUDA response to sync (4)");
 415     (void)in_8(&via[SR]);
 416     out_8(&via[IFR], SR_INT);
 417
 418     return 0;
 419 }
 420
 421 #ifdef CONFIG_ADB
 422 /* Send an ADB command */
 423 static int
 424 cuda_send_request(struct adb_request *req, int sync)
 425 {
 426     int i;
 427
 428     if ((via == NULL) || !cuda_fully_inited) {
 429         req->complete = 1;
 430         return -ENXIO;
 431     }
 432
 433     req->reply_expected = 1;
 434
 435     i = cuda_write(req);
 436     if (i)
 437         return i;
 438
 439     if (sync) {
 440         while (!req->complete)
 441             cuda_poll();
 442     }
 443     return 0;
 444 }
 445
 446
 447 /* Enable/disable autopolling */
 448 static int
 449 cuda_adb_autopoll(int devs)
 450 {
 451     struct adb_request req;
 452
 453     if ((via == NULL) || !cuda_fully_inited)
 454         return -ENXIO;
 455
 456     cuda_request(&req, NULL, 3, CUDA_PACKET, CUDA_AUTOPOLL, (devs? 1: 0));
 457     while (!req.complete)
 458         cuda_poll();
 459     return 0;
 460 }
 461
 462 /* Reset adb bus - how do we do this?? */
 463 static int
 464 cuda_reset_adb_bus(void)
 465 {
 466     struct adb_request req;
 467
 468     if ((via == NULL) || !cuda_fully_inited)
 469         return -ENXIO;
 470
 471     cuda_request(&req, NULL, 2, ADB_PACKET, 0);         /* maybe? */
 472     while (!req.complete)
 473         cuda_poll();
 474     return 0;
 475 }
 476 #endif /* CONFIG_ADB */
 477
 478 /* Construct and send a cuda request */
 479 int
 480 cuda_request(struct adb_request *req, void (*done)(struct adb_request *),
 481              int nbytes, ...)
 482 {
 483     va_list list;
 484     int i;
 485
 486     if (via == NULL) {
 487         req->complete = 1;
 488         return -ENXIO;
 489     }
 490
 491     req->nbytes = nbytes;
 492     req->done = done;
 493     va_start(list, nbytes);
 494     for (i = 0; i < nbytes; ++i)
 495         req->data[i] = va_arg(list, int);
 496     va_end(list);
 497     req->reply_expected = 1;
 498     return cuda_write(req);
 499 }
 500 EXPORT_SYMBOL(cuda_request);
 501
 502 static int
 503 cuda_write(struct adb_request *req)
 504 {
 505     unsigned long flags;
 506
 507     if (req->nbytes < 2 || req->data[0] > CUDA_PACKET) {
 508         req->complete = 1;
 509         return -EINVAL;
 510     }
 511     req->next = NULL;
 512     req->sent = 0;
 513     req->complete = 0;
 514     req->reply_len = 0;
 515
 516     spin_lock_irqsave(&cuda_lock, flags);
 517     if (current_req) {
 518         last_req->next = req;
 519         last_req = req;
 520     } else {
 521         current_req = req;
 522         last_req = req;
 523         if (cuda_state == idle)
 524             cuda_start();
 525     }
 526     spin_unlock_irqrestore(&cuda_lock, flags);
 527
 528     return 0;
 529 }
 530
 531 static void
 532 cuda_start(void)
 533 {
 534     /* assert cuda_state == idle */
 535     if (current_req == NULL)
 536         return;
 537     data_index = 0;
 538     if (TREQ_asserted(in_8(&via[B])))
 539         return;                 /* a byte is coming in from the CUDA */
 540
 541     /* set the shift register to shift out and send a byte */
 542     out_8(&via[ACR], in_8(&via[ACR]) | SR_OUT);
 543     out_8(&via[SR], current_req->data[data_index++]);
 544     if (mcu_is_egret)
 545         assert_TIP_and_TACK();
 546     else
 547         assert_TIP();
 548     cuda_state = sent_first_byte;
 549 }
 550
 551 void
 552 cuda_poll(void)
 553 {
 554         cuda_interrupt(0, NULL);
 555 }
 556 EXPORT_SYMBOL(cuda_poll);
 557
 558 #define ARRAY_FULL(a, p)        ((p) - (a) == ARRAY_SIZE(a))
 559
 560 static irqreturn_t
 561 cuda_interrupt(int irq, void *arg)
 562 {
 563     unsigned long flags;
 564     u8 status;
 565     struct adb_request *req = NULL;
 566     unsigned char ibuf[16];
 567     int ibuf_len = 0;
 568     int complete = 0;
 569     bool full;
 570
 571     spin_lock_irqsave(&cuda_lock, flags);
 572
 573     /* On powermacs, this handler is registered for the VIA IRQ. But they use
 574      * just the shift register IRQ -- other VIA interrupt sources are disabled.
 575      * On m68k macs, the VIA IRQ sources are dispatched individually. Unless
 576      * we are polling, the shift register IRQ flag has already been cleared.
 577      */
 578
 579 #ifdef CONFIG_MAC
 580     if (!arg)
 581 #endif
 582     {
 583         if ((in_8(&via[IFR]) & SR_INT) == 0) {
 584             spin_unlock_irqrestore(&cuda_lock, flags);
 585             return IRQ_NONE;
 586         } else {
 587             out_8(&via[IFR], SR_INT);
 588         }
 589     }
 590
 591     status = in_8(&via[B]) & (TIP | TACK | TREQ);
 592
 593     switch (cuda_state) {
 594     case idle:
 595         /* System controller has unsolicited data for us */
 596         (void)in_8(&via[SR]);
 597 idle_state:
 598         assert_TIP();
 599         cuda_state = reading;
 600         reply_ptr = cuda_rbuf;
 601         reading_reply = 0;
 602         break;
 603
 604     case awaiting_reply:
 605         /* System controller has reply data for us */
 606         (void)in_8(&via[SR]);
 607         assert_TIP();
 608         cuda_state = reading;
 609         reply_ptr = current_req->reply;
 610         reading_reply = 1;
 611         break;
 612
 613     case sent_first_byte:
 614         if (TREQ_asserted(status)) {
 615             /* collision */
 616             out_8(&via[ACR], in_8(&via[ACR]) & ~SR_OUT);
 617             (void)in_8(&via[SR]);
 618             negate_TIP_and_TACK();
 619             cuda_state = idle;
 620             /* Egret does not raise an "aborted" interrupt */
 621             if (mcu_is_egret)
 622                 goto idle_state;
 623         } else {
 624             out_8(&via[SR], current_req->data[data_index++]);
 625             toggle_TACK();
 626             if (mcu_is_egret)
 627                 assert_TACK();
 628             cuda_state = sending;
 629         }
 630         break;
 631
 632     case sending:
 633         req = current_req;
 634         if (data_index >= req->nbytes) {
 635             out_8(&via[ACR], in_8(&via[ACR]) & ~SR_OUT);
 636             (void)in_8(&via[SR]);
 637             negate_TIP_and_TACK();
 638             req->sent = 1;
 639             if (req->reply_expected) {
 640                 cuda_state = awaiting_reply;
 641             } else {
 642                 current_req = req->next;
 643                 complete = 1;
 644                 /* not sure about this */
 645                 cuda_state = idle;
 646                 cuda_start();
 647             }
 648         } else {
 649             out_8(&via[SR], req->data[data_index++]);
 650             toggle_TACK();
 651             if (mcu_is_egret)
 652                 assert_TACK();
 653         }
 654         break;
 655
 656     case reading:
 657         full = reading_reply ? ARRAY_FULL(current_req->reply, reply_ptr)
 658                              : ARRAY_FULL(cuda_rbuf, reply_ptr);
 659         if (full)
 660             (void)in_8(&via[SR]);
 661         else
 662             *reply_ptr++ = in_8(&via[SR]);
 663         if (!TREQ_asserted(status) || full) {
 664             if (mcu_is_egret)
 665                 assert_TACK();
 666             /* that's all folks */
 667             negate_TIP_and_TACK();
 668             cuda_state = read_done;
 669             /* Egret does not raise a "read done" interrupt */
 670             if (mcu_is_egret)
 671                 goto read_done_state;
 672         } else {
 673             toggle_TACK();
 674             if (mcu_is_egret)
 675                 negate_TACK();
 676         }
 677         break;
 678
 679     case read_done:
 680         (void)in_8(&via[SR]);
 681 read_done_state:
 682         if (reading_reply) {
 683             req = current_req;
 684             req->reply_len = reply_ptr - req->reply;
 685             if (req->data[0] == ADB_PACKET) {
 686                 /* Have to adjust the reply from ADB commands */
 687                 if (req->reply_len <= 2 || (req->reply[1] & 2) != 0) {
 688                     /* the 0x2 bit indicates no response */
 689                     req->reply_len = 0;
 690                 } else {
 691                     /* leave just the command and result bytes in the reply */
 692                     req->reply_len -= 2;
 693                     memmove(req->reply, req->reply + 2, req->reply_len);
 694                 }
 695             }
 696             current_req = req->next;
 697             complete = 1;
 698             reading_reply = 0;
 699         } else {
 700             /* This is tricky. We must break the spinlock to call
 701              * cuda_input. However, doing so means we might get
 702              * re-entered from another CPU getting an interrupt
 703              * or calling cuda_poll(). I ended up using the stack
 704              * (it's only for 16 bytes) and moving the actual
 705              * call to cuda_input to outside of the lock.
 706              */
 707             ibuf_len = reply_ptr - cuda_rbuf;
 708             memcpy(ibuf, cuda_rbuf, ibuf_len);
 709         }
 710         reply_ptr = cuda_rbuf;
 711         cuda_state = idle;
 712         cuda_start();
 713         if (cuda_state == idle && TREQ_asserted(in_8(&via[B]))) {
 714             assert_TIP();
 715             cuda_state = reading;
 716         }
 717         break;
 718
 719     default:
 720         pr_err("cuda_interrupt: unknown cuda_state %d?\n", cuda_state);
 721     }
 722     spin_unlock_irqrestore(&cuda_lock, flags);
 723     if (complete && req) {
 724         void (*done)(struct adb_request *) = req->done;
 725         mb();
 726         req->complete = 1;
 727         /* Here, we assume that if the request has a done member, the
 728          * struct request will survive to setting req->complete to 1
 729          */
 730         if (done)
 731                 (*done)(req);
 732     }
 733     if (ibuf_len)
 734         cuda_input(ibuf, ibuf_len);
 735     return IRQ_HANDLED;
 736 }
 737
 738 static void
 739 cuda_input(unsigned char *buf, int nb)
 740 {
 741     switch (buf[0]) {
 742     case ADB_PACKET:
 743 #ifdef CONFIG_XMON
 744         if (nb == 5 && buf[2] == 0x2c) {
 745             extern int xmon_wants_key, xmon_adb_keycode;
 746             if (xmon_wants_key) {
 747                 xmon_adb_keycode = buf[3];
 748                 return;
 749             }
 750         }
 751 #endif /* CONFIG_XMON */
 752 #ifdef CONFIG_ADB
 753         adb_input(buf+2, nb-2, buf[1] & 0x40);
 754 #endif /* CONFIG_ADB */
 755         break;
 756
 757     case TIMER_PACKET:
 758         /* Egret sends these periodically. Might be useful as a 'heartbeat'
 759          * to trigger a recovery for the VIA shift register errata.
 760          */
 761         break;
 762
 763     default:
 764         print_hex_dump(KERN_INFO, "cuda_input: ", DUMP_PREFIX_NONE, 32, 1,
 765                        buf, nb, false);
 766     }
 767 }
 768
 769 /* Offset between Unix time (1970-based) and Mac time (1904-based) */
 770 #define RTC_OFFSET      2082844800
 771
 772 time64_t cuda_get_time(void)
 773 {
 774         struct adb_request req;
 775         u32 now;
 776
 777         if (cuda_request(&req, NULL, 2, CUDA_PACKET, CUDA_GET_TIME) < 0)
 778                 return 0;
 779         while (!req.complete)
 780                 cuda_poll();
 781         if (req.reply_len != 7)
 782                 pr_err("%s: got %d byte reply\n", __func__, req.reply_len);
 783         now = (req.reply[3] << 24) + (req.reply[4] << 16) +
 784               (req.reply[5] << 8) + req.reply[6];
 785         return (time64_t)now - RTC_OFFSET;
 786 }
 787
 788 int cuda_set_rtc_time(struct rtc_time *tm)
 789 {
 790         u32 now;
 791         struct adb_request req;
 792
 793         now = lower_32_bits(rtc_tm_to_time64(tm) + RTC_OFFSET);
 794         if (cuda_request(&req, NULL, 6, CUDA_PACKET, CUDA_SET_TIME,
 795                          now >> 24, now >> 16, now >> 8, now) < 0)
 796                 return -ENXIO;
 797         while (!req.complete)
 798                 cuda_poll();
 799         if ((req.reply_len != 3) && (req.reply_len != 7))
 800                 pr_err("%s: got %d byte reply\n", __func__, req.reply_len);
 801         return 0;
 802 }