linux/drivers/macintosh/via-cuda.c
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   1/*
   2 * Device driver for the via-cuda on Apple Powermacs.
   3 *
   4 * The VIA (versatile interface adapter) interfaces to the CUDA,
   5 * a 6805 microprocessor core which controls the ADB (Apple Desktop
   6 * Bus) which connects to the keyboard and mouse.  The CUDA also
   7 * controls system power and the RTC (real time clock) chip.
   8 *
   9 * Copyright (C) 1996 Paul Mackerras.
  10 */
  11#include <stdarg.h>
  12#include <linux/types.h>
  13#include <linux/errno.h>
  14#include <linux/kernel.h>
  15#include <linux/delay.h>
  16#include <linux/adb.h>
  17#include <linux/cuda.h>
  18#include <linux/spinlock.h>
  19#include <linux/interrupt.h>
  20#ifdef CONFIG_PPC
  21#include <asm/prom.h>
  22#include <asm/machdep.h>
  23#else
  24#include <asm/macintosh.h>
  25#include <asm/macints.h>
  26#include <asm/mac_via.h>
  27#endif
  28#include <asm/io.h>
  29#include <linux/init.h>
  30
  31static volatile unsigned char __iomem *via;
  32static DEFINE_SPINLOCK(cuda_lock);
  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
  58/* Bits in ACR */
  59#define SR_CTRL         0x1c            /* Shift register control bits */
  60#define SR_EXT          0x0c            /* Shift on external clock */
  61#define SR_OUT          0x10            /* Shift out if 1 */
  62
  63/* Bits in IFR and IER */
  64#define IER_SET         0x80            /* set bits in IER */
  65#define IER_CLR         0               /* clear bits in IER */
  66#define SR_INT          0x04            /* Shift register full/empty */
  67
  68static enum cuda_state {
  69    idle,
  70    sent_first_byte,
  71    sending,
  72    reading,
  73    read_done,
  74    awaiting_reply
  75} cuda_state;
  76
  77static struct adb_request *current_req;
  78static struct adb_request *last_req;
  79static unsigned char cuda_rbuf[16];
  80static unsigned char *reply_ptr;
  81static int reading_reply;
  82static int data_index;
  83static int cuda_irq;
  84#ifdef CONFIG_PPC
  85static struct device_node *vias;
  86#endif
  87static int cuda_fully_inited;
  88
  89#ifdef CONFIG_ADB
  90static int cuda_probe(void);
  91static int cuda_send_request(struct adb_request *req, int sync);
  92static int cuda_adb_autopoll(int devs);
  93static int cuda_reset_adb_bus(void);
  94#endif /* CONFIG_ADB */
  95
  96static int cuda_init_via(void);
  97static void cuda_start(void);
  98static irqreturn_t cuda_interrupt(int irq, void *arg);
  99static void cuda_input(unsigned char *buf, int nb);
 100void cuda_poll(void);
 101static int cuda_write(struct adb_request *req);
 102
 103int cuda_request(struct adb_request *req,
 104                 void (*done)(struct adb_request *), int nbytes, ...);
 105
 106#ifdef CONFIG_ADB
 107struct adb_driver via_cuda_driver = {
 108        .name         = "CUDA",
 109        .probe        = cuda_probe,
 110        .send_request = cuda_send_request,
 111        .autopoll     = cuda_adb_autopoll,
 112        .poll         = cuda_poll,
 113        .reset_bus    = cuda_reset_adb_bus,
 114};
 115#endif /* CONFIG_ADB */
 116
 117#ifdef CONFIG_MAC
 118int __init find_via_cuda(void)
 119{
 120    struct adb_request req;
 121    int err;
 122
 123    if (macintosh_config->adb_type != MAC_ADB_CUDA)
 124        return 0;
 125
 126    via = via1;
 127    cuda_state = idle;
 128
 129    err = cuda_init_via();
 130    if (err) {
 131        printk(KERN_ERR "cuda_init_via() failed\n");
 132        via = NULL;
 133        return 0;
 134    }
 135
 136    /* enable autopoll */
 137    cuda_request(&req, NULL, 3, CUDA_PACKET, CUDA_AUTOPOLL, 1);
 138    while (!req.complete)
 139        cuda_poll();
 140
 141    return 1;
 142}
 143#else
 144int __init find_via_cuda(void)
 145{
 146    struct adb_request req;
 147    phys_addr_t taddr;
 148    const u32 *reg;
 149    int err;
 150
 151    if (vias != 0)
 152        return 1;
 153    vias = of_find_node_by_name(NULL, "via-cuda");
 154    if (vias == 0)
 155        return 0;
 156
 157    reg = of_get_property(vias, "reg", NULL);
 158    if (reg == NULL) {
 159            printk(KERN_ERR "via-cuda: No \"reg\" property !\n");
 160            goto fail;
 161    }
 162    taddr = of_translate_address(vias, reg);
 163    if (taddr == 0) {
 164            printk(KERN_ERR "via-cuda: Can't translate address !\n");
 165            goto fail;
 166    }
 167    via = ioremap(taddr, 0x2000);
 168    if (via == NULL) {
 169            printk(KERN_ERR "via-cuda: Can't map address !\n");
 170            goto fail;
 171    }
 172
 173    cuda_state = idle;
 174    sys_ctrler = SYS_CTRLER_CUDA;
 175
 176    err = cuda_init_via();
 177    if (err) {
 178        printk(KERN_ERR "cuda_init_via() failed\n");
 179        via = NULL;
 180        return 0;
 181    }
 182
 183    /* Clear and enable interrupts, but only on PPC. On 68K it's done  */
 184    /* for us by the main VIA driver in arch/m68k/mac/via.c        */
 185
 186    out_8(&via[IFR], 0x7f);     /* clear interrupts by writing 1s */
 187    out_8(&via[IER], IER_SET|SR_INT); /* enable interrupt from SR */
 188
 189    /* enable autopoll */
 190    cuda_request(&req, NULL, 3, CUDA_PACKET, CUDA_AUTOPOLL, 1);
 191    while (!req.complete)
 192        cuda_poll();
 193
 194    return 1;
 195
 196 fail:
 197    of_node_put(vias);
 198    vias = NULL;
 199    return 0;
 200}
 201#endif /* !defined CONFIG_MAC */
 202
 203static int __init via_cuda_start(void)
 204{
 205    if (via == NULL)
 206        return -ENODEV;
 207
 208#ifdef CONFIG_MAC
 209    cuda_irq = IRQ_MAC_ADB;
 210#else
 211    cuda_irq = irq_of_parse_and_map(vias, 0);
 212    if (cuda_irq == NO_IRQ) {
 213        printk(KERN_ERR "via-cuda: can't map interrupts for %s\n",
 214               vias->full_name);
 215        return -ENODEV;
 216    }
 217#endif
 218
 219    if (request_irq(cuda_irq, cuda_interrupt, 0, "ADB", cuda_interrupt)) {
 220        printk(KERN_ERR "via-cuda: can't request irq %d\n", cuda_irq);
 221        return -EAGAIN;
 222    }
 223
 224    printk("Macintosh CUDA driver v0.5 for Unified ADB.\n");
 225
 226    cuda_fully_inited = 1;
 227    return 0;
 228}
 229
 230device_initcall(via_cuda_start);
 231
 232#ifdef CONFIG_ADB
 233static int
 234cuda_probe(void)
 235{
 236#ifdef CONFIG_PPC
 237    if (sys_ctrler != SYS_CTRLER_CUDA)
 238        return -ENODEV;
 239#else
 240    if (macintosh_config->adb_type != MAC_ADB_CUDA)
 241        return -ENODEV;
 242#endif
 243    if (via == NULL)
 244        return -ENODEV;
 245    return 0;
 246}
 247#endif /* CONFIG_ADB */
 248
 249#define WAIT_FOR(cond, what)                                    \
 250    do {                                                        \
 251        int x;                                                  \
 252        for (x = 1000; !(cond); --x) {                          \
 253            if (x == 0) {                                       \
 254                printk("Timeout waiting for " what "\n");       \
 255                return -ENXIO;                                  \
 256            }                                                   \
 257            udelay(100);                                        \
 258        }                                                       \
 259    } while (0)
 260
 261static int
 262cuda_init_via(void)
 263{
 264    out_8(&via[DIRB], (in_8(&via[DIRB]) | TACK | TIP) & ~TREQ); /* TACK & TIP out */
 265    out_8(&via[B], in_8(&via[B]) | TACK | TIP);                 /* negate them */
 266    out_8(&via[ACR] ,(in_8(&via[ACR]) & ~SR_CTRL) | SR_EXT);    /* SR data in */
 267    (void)in_8(&via[SR]);                                               /* clear any left-over data */
 268#ifdef CONFIG_PPC
 269    out_8(&via[IER], 0x7f);                                     /* disable interrupts from VIA */
 270    (void)in_8(&via[IER]);
 271#else
 272    out_8(&via[IER], SR_INT);                                   /* disable SR interrupt from VIA */
 273#endif
 274
 275    /* delay 4ms and then clear any pending interrupt */
 276    mdelay(4);
 277    (void)in_8(&via[SR]);
 278    out_8(&via[IFR], SR_INT);
 279
 280    /* sync with the CUDA - assert TACK without TIP */
 281    out_8(&via[B], in_8(&via[B]) & ~TACK);
 282
 283    /* wait for the CUDA to assert TREQ in response */
 284    WAIT_FOR((in_8(&via[B]) & TREQ) == 0, "CUDA response to sync");
 285
 286    /* wait for the interrupt and then clear it */
 287    WAIT_FOR(in_8(&via[IFR]) & SR_INT, "CUDA response to sync (2)");
 288    (void)in_8(&via[SR]);
 289    out_8(&via[IFR], SR_INT);
 290
 291    /* finish the sync by negating TACK */
 292    out_8(&via[B], in_8(&via[B]) | TACK);
 293
 294    /* wait for the CUDA to negate TREQ and the corresponding interrupt */
 295    WAIT_FOR(in_8(&via[B]) & TREQ, "CUDA response to sync (3)");
 296    WAIT_FOR(in_8(&via[IFR]) & SR_INT, "CUDA response to sync (4)");
 297    (void)in_8(&via[SR]);
 298    out_8(&via[IFR], SR_INT);
 299    out_8(&via[B], in_8(&via[B]) | TIP);        /* should be unnecessary */
 300
 301    return 0;
 302}
 303
 304#ifdef CONFIG_ADB
 305/* Send an ADB command */
 306static int
 307cuda_send_request(struct adb_request *req, int sync)
 308{
 309    int i;
 310
 311    if ((via == NULL) || !cuda_fully_inited) {
 312        req->complete = 1;
 313        return -ENXIO;
 314    }
 315  
 316    req->reply_expected = 1;
 317
 318    i = cuda_write(req);
 319    if (i)
 320        return i;
 321
 322    if (sync) {
 323        while (!req->complete)
 324            cuda_poll();
 325    }
 326    return 0;
 327}
 328
 329
 330/* Enable/disable autopolling */
 331static int
 332cuda_adb_autopoll(int devs)
 333{
 334    struct adb_request req;
 335
 336    if ((via == NULL) || !cuda_fully_inited)
 337        return -ENXIO;
 338
 339    cuda_request(&req, NULL, 3, CUDA_PACKET, CUDA_AUTOPOLL, (devs? 1: 0));
 340    while (!req.complete)
 341        cuda_poll();
 342    return 0;
 343}
 344
 345/* Reset adb bus - how do we do this?? */
 346static int
 347cuda_reset_adb_bus(void)
 348{
 349    struct adb_request req;
 350
 351    if ((via == NULL) || !cuda_fully_inited)
 352        return -ENXIO;
 353
 354    cuda_request(&req, NULL, 2, ADB_PACKET, 0);         /* maybe? */
 355    while (!req.complete)
 356        cuda_poll();
 357    return 0;
 358}
 359#endif /* CONFIG_ADB */
 360/* Construct and send a cuda request */
 361int
 362cuda_request(struct adb_request *req, void (*done)(struct adb_request *),
 363             int nbytes, ...)
 364{
 365    va_list list;
 366    int i;
 367
 368    if (via == NULL) {
 369        req->complete = 1;
 370        return -ENXIO;
 371    }
 372
 373    req->nbytes = nbytes;
 374    req->done = done;
 375    va_start(list, nbytes);
 376    for (i = 0; i < nbytes; ++i)
 377        req->data[i] = va_arg(list, int);
 378    va_end(list);
 379    req->reply_expected = 1;
 380    return cuda_write(req);
 381}
 382
 383static int
 384cuda_write(struct adb_request *req)
 385{
 386    unsigned long flags;
 387
 388    if (req->nbytes < 2 || req->data[0] > CUDA_PACKET) {
 389        req->complete = 1;
 390        return -EINVAL;
 391    }
 392    req->next = NULL;
 393    req->sent = 0;
 394    req->complete = 0;
 395    req->reply_len = 0;
 396
 397    spin_lock_irqsave(&cuda_lock, flags);
 398    if (current_req != 0) {
 399        last_req->next = req;
 400        last_req = req;
 401    } else {
 402        current_req = req;
 403        last_req = req;
 404        if (cuda_state == idle)
 405            cuda_start();
 406    }
 407    spin_unlock_irqrestore(&cuda_lock, flags);
 408
 409    return 0;
 410}
 411
 412static void
 413cuda_start(void)
 414{
 415    struct adb_request *req;
 416
 417    /* assert cuda_state == idle */
 418    /* get the packet to send */
 419    req = current_req;
 420    if (req == 0)
 421        return;
 422    if ((in_8(&via[B]) & TREQ) == 0)
 423        return;                 /* a byte is coming in from the CUDA */
 424
 425    /* set the shift register to shift out and send a byte */
 426    out_8(&via[ACR], in_8(&via[ACR]) | SR_OUT);
 427    out_8(&via[SR], req->data[0]);
 428    out_8(&via[B], in_8(&via[B]) & ~TIP);
 429    cuda_state = sent_first_byte;
 430}
 431
 432void
 433cuda_poll(void)
 434{
 435    /* cuda_interrupt only takes a normal lock, we disable
 436     * interrupts here to avoid re-entering and thus deadlocking.
 437     */
 438    if (cuda_irq)
 439        disable_irq(cuda_irq);
 440    cuda_interrupt(0, NULL);
 441    if (cuda_irq)
 442        enable_irq(cuda_irq);
 443}
 444
 445static irqreturn_t
 446cuda_interrupt(int irq, void *arg)
 447{
 448    int status;
 449    struct adb_request *req = NULL;
 450    unsigned char ibuf[16];
 451    int ibuf_len = 0;
 452    int complete = 0;
 453    
 454    spin_lock(&cuda_lock);
 455
 456    /* On powermacs, this handler is registered for the VIA IRQ. But they use
 457     * just the shift register IRQ -- other VIA interrupt sources are disabled.
 458     * On m68k macs, the VIA IRQ sources are dispatched individually. Unless
 459     * we are polling, the shift register IRQ flag has already been cleared.
 460     */
 461
 462#ifdef CONFIG_MAC
 463    if (!arg)
 464#endif
 465    {
 466        if ((in_8(&via[IFR]) & SR_INT) == 0) {
 467            spin_unlock(&cuda_lock);
 468            return IRQ_NONE;
 469        } else {
 470            out_8(&via[IFR], SR_INT);
 471        }
 472    }
 473    
 474    status = (~in_8(&via[B]) & (TIP|TREQ)) | (in_8(&via[ACR]) & SR_OUT);
 475    /* printk("cuda_interrupt: state=%d status=%x\n", cuda_state, status); */
 476    switch (cuda_state) {
 477    case idle:
 478        /* CUDA has sent us the first byte of data - unsolicited */
 479        if (status != TREQ)
 480            printk("cuda: state=idle, status=%x\n", status);
 481        (void)in_8(&via[SR]);
 482        out_8(&via[B], in_8(&via[B]) & ~TIP);
 483        cuda_state = reading;
 484        reply_ptr = cuda_rbuf;
 485        reading_reply = 0;
 486        break;
 487
 488    case awaiting_reply:
 489        /* CUDA has sent us the first byte of data of a reply */
 490        if (status != TREQ)
 491            printk("cuda: state=awaiting_reply, status=%x\n", status);
 492        (void)in_8(&via[SR]);
 493        out_8(&via[B], in_8(&via[B]) & ~TIP);
 494        cuda_state = reading;
 495        reply_ptr = current_req->reply;
 496        reading_reply = 1;
 497        break;
 498
 499    case sent_first_byte:
 500        if (status == TREQ + TIP + SR_OUT) {
 501            /* collision */
 502            out_8(&via[ACR], in_8(&via[ACR]) & ~SR_OUT);
 503            (void)in_8(&via[SR]);
 504            out_8(&via[B], in_8(&via[B]) | TIP | TACK);
 505            cuda_state = idle;
 506        } else {
 507            /* assert status == TIP + SR_OUT */
 508            if (status != TIP + SR_OUT)
 509                printk("cuda: state=sent_first_byte status=%x\n", status);
 510            out_8(&via[SR], current_req->data[1]);
 511            out_8(&via[B], in_8(&via[B]) ^ TACK);
 512            data_index = 2;
 513            cuda_state = sending;
 514        }
 515        break;
 516
 517    case sending:
 518        req = current_req;
 519        if (data_index >= req->nbytes) {
 520            out_8(&via[ACR], in_8(&via[ACR]) & ~SR_OUT);
 521            (void)in_8(&via[SR]);
 522            out_8(&via[B], in_8(&via[B]) | TACK | TIP);
 523            req->sent = 1;
 524            if (req->reply_expected) {
 525                cuda_state = awaiting_reply;
 526            } else {
 527                current_req = req->next;
 528                complete = 1;
 529                /* not sure about this */
 530                cuda_state = idle;
 531                cuda_start();
 532            }
 533        } else {
 534            out_8(&via[SR], req->data[data_index++]);
 535            out_8(&via[B], in_8(&via[B]) ^ TACK);
 536        }
 537        break;
 538
 539    case reading:
 540        *reply_ptr++ = in_8(&via[SR]);
 541        if (status == TIP) {
 542            /* that's all folks */
 543            out_8(&via[B], in_8(&via[B]) | TACK | TIP);
 544            cuda_state = read_done;
 545        } else {
 546            /* assert status == TIP | TREQ */
 547            if (status != TIP + TREQ)
 548                printk("cuda: state=reading status=%x\n", status);
 549            out_8(&via[B], in_8(&via[B]) ^ TACK);
 550        }
 551        break;
 552
 553    case read_done:
 554        (void)in_8(&via[SR]);
 555        if (reading_reply) {
 556            req = current_req;
 557            req->reply_len = reply_ptr - req->reply;
 558            if (req->data[0] == ADB_PACKET) {
 559                /* Have to adjust the reply from ADB commands */
 560                if (req->reply_len <= 2 || (req->reply[1] & 2) != 0) {
 561                    /* the 0x2 bit indicates no response */
 562                    req->reply_len = 0;
 563                } else {
 564                    /* leave just the command and result bytes in the reply */
 565                    req->reply_len -= 2;
 566                    memmove(req->reply, req->reply + 2, req->reply_len);
 567                }
 568            }
 569            current_req = req->next;
 570            complete = 1;
 571        } else {
 572            /* This is tricky. We must break the spinlock to call
 573             * cuda_input. However, doing so means we might get
 574             * re-entered from another CPU getting an interrupt
 575             * or calling cuda_poll(). I ended up using the stack
 576             * (it's only for 16 bytes) and moving the actual
 577             * call to cuda_input to outside of the lock.
 578             */
 579            ibuf_len = reply_ptr - cuda_rbuf;
 580            memcpy(ibuf, cuda_rbuf, ibuf_len);
 581        }
 582        if (status == TREQ) {
 583            out_8(&via[B], in_8(&via[B]) & ~TIP);
 584            cuda_state = reading;
 585            reply_ptr = cuda_rbuf;
 586            reading_reply = 0;
 587        } else {
 588            cuda_state = idle;
 589            cuda_start();
 590        }
 591        break;
 592
 593    default:
 594        printk("cuda_interrupt: unknown cuda_state %d?\n", cuda_state);
 595    }
 596    spin_unlock(&cuda_lock);
 597    if (complete && req) {
 598        void (*done)(struct adb_request *) = req->done;
 599        mb();
 600        req->complete = 1;
 601        /* Here, we assume that if the request has a done member, the
 602         * struct request will survive to setting req->complete to 1
 603         */
 604        if (done)
 605                (*done)(req);
 606    }
 607    if (ibuf_len)
 608        cuda_input(ibuf, ibuf_len);
 609    return IRQ_HANDLED;
 610}
 611
 612static void
 613cuda_input(unsigned char *buf, int nb)
 614{
 615    int i;
 616
 617    switch (buf[0]) {
 618    case ADB_PACKET:
 619#ifdef CONFIG_XMON
 620        if (nb == 5 && buf[2] == 0x2c) {
 621            extern int xmon_wants_key, xmon_adb_keycode;
 622            if (xmon_wants_key) {
 623                xmon_adb_keycode = buf[3];
 624                return;
 625            }
 626        }
 627#endif /* CONFIG_XMON */
 628#ifdef CONFIG_ADB
 629        adb_input(buf+2, nb-2, buf[1] & 0x40);
 630#endif /* CONFIG_ADB */
 631        break;
 632
 633    default:
 634        printk("data from cuda (%d bytes):", nb);
 635        for (i = 0; i < nb; ++i)
 636            printk(" %.2x", buf[i]);
 637        printk("\n");
 638    }
 639}
 640
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