via-maciisi.c

Go to the documentation of this file.

/*
 * Device driver for the IIsi-style ADB on some Mac LC and II-class machines
 *
 * Based on via-cuda.c and via-macii.c, as well as the original
 * adb-bus.c, which in turn is somewhat influenced by (but uses no
 * code from) the NetBSD HWDIRECT ADB code.  Original IIsi driver work
 * was done by Robert Thompson and integrated into the old style
 * driver by Michael Schmitz.
 *
 * Original sources (c) Alan Cox, Paul Mackerras, and others.
 *
 * Rewritten for Unified ADB by David Huggins-Daines <[email protected]>
 * 
 * 7/13/2000- extensive changes by Andrew McPherson <[email protected]>
 * Works about 30% of the time now.
 */

#include <linux/types.h>
#include <linux/errno.h>
#include <linux/kernel.h>
#include <linux/adb.h>
#include <linux/cuda.h>
#include <linux/delay.h>
#include <linux/interrupt.h>
#include <asm/macintosh.h>
#include <asm/macints.h>
#include <asm/mac_via.h>

static volatile unsigned char *via;

/* VIA registers - spaced 0x200 bytes apart - only the ones we actually use */
#define RS      0x200       /* skip between registers */
#define B       0       /* B-side data */
#define A       RS      /* A-side data */
#define DIRB        (2*RS)      /* B-side direction (1=output) */
#define DIRA        (3*RS)      /* A-side direction (1=output) */
#define SR      (10*RS)     /* Shift register */
#define ACR     (11*RS)     /* Auxiliary control register */
#define IFR     (13*RS)     /* Interrupt flag register */
#define IER     (14*RS)     /* Interrupt enable register */

/* Bits in B data register: all active low */
#define TREQ        0x08        /* Transfer request (input) */
#define TACK        0x10        /* Transfer acknowledge (output) */
#define TIP     0x20        /* Transfer in progress (output) */
#define ST_MASK     0x30        /* mask for selecting ADB state bits */

/* Bits in ACR */
#define SR_CTRL     0x1c        /* Shift register control bits */
#define SR_EXT      0x0c        /* Shift on external clock */
#define SR_OUT      0x10        /* Shift out if 1 */

/* Bits in IFR and IER */
#define IER_SET     0x80        /* set bits in IER */
#define IER_CLR     0       /* clear bits in IER */
#define SR_INT      0x04        /* Shift register full/empty */
#define SR_DATA     0x08        /* Shift register data */
#define SR_CLOCK    0x10        /* Shift register clock */

#define ADB_DELAY 150

#undef DEBUG_MACIISI_ADB

static struct adb_request* current_req;
static struct adb_request* last_req;
static unsigned char maciisi_rbuf[16];
static unsigned char *reply_ptr;
static int data_index;
static int reading_reply;
static int reply_len;
static int tmp;
static int need_sync;

static enum maciisi_state {
    idle,
    sending,
    reading,
} maciisi_state;

static int maciisi_probe(void);
static int maciisi_init(void);
static int maciisi_send_request(struct adb_request* req, int sync);
static void maciisi_sync(struct adb_request *req);
static int maciisi_write(struct adb_request* req);
static irqreturn_t maciisi_interrupt(int irq, void* arg);
static void maciisi_input(unsigned char *buf, int nb);
static int maciisi_init_via(void);
static void maciisi_poll(void);
static int maciisi_start(void);

struct adb_driver via_maciisi_driver = {
    "Mac IIsi",
    maciisi_probe,
    maciisi_init,
    maciisi_send_request,
    NULL, /* maciisi_adb_autopoll, */
    maciisi_poll,
    NULL /* maciisi_reset_adb_bus */
};

static int
maciisi_probe(void)
{
    if (macintosh_config->adb_type != MAC_ADB_IISI)
        return -ENODEV;

    via = via1;
    return 0;
}

static int
maciisi_init(void)
{
    int err;

    if (via == NULL)
        return -ENODEV;

    if ((err = maciisi_init_via())) {
        printk(KERN_ERR "maciisi_init: maciisi_init_via() failed, code %d\n", err);
        via = NULL;
        return err;
    }

    if (request_irq(IRQ_MAC_ADB, maciisi_interrupt, 0, "ADB",
            maciisi_interrupt)) {
        printk(KERN_ERR "maciisi_init: can't get irq %d\n", IRQ_MAC_ADB);
        return -EAGAIN;
    }

    printk("adb: Mac IIsi driver v0.2 for Unified ADB.\n");
    return 0;
}

/* Flush data from the ADB controller */
static void
maciisi_stfu(void)
{
    int status = via[B] & (TIP|TREQ);

    if (status & TREQ) {
#ifdef DEBUG_MACIISI_ADB
        printk (KERN_DEBUG "maciisi_stfu called with TREQ high!\n");
#endif
        return;
    }
    
    udelay(ADB_DELAY);
    via[ACR] &= ~SR_OUT;
    via[IER] = IER_CLR | SR_INT;

    udelay(ADB_DELAY);

    status = via[B] & (TIP|TREQ);

    if (!(status & TREQ))
    {
        via[B] |= TIP;

        while(1)
        {
            int poll_timeout = ADB_DELAY * 5;
            /* Poll for SR interrupt */
            while (!(via[IFR] & SR_INT) && poll_timeout-- > 0)
                status = via[B] & (TIP|TREQ);

            tmp = via[SR]; /* Clear shift register */
#ifdef DEBUG_MACIISI_ADB
            printk(KERN_DEBUG "maciisi_stfu: status %x timeout %d data %x\n",
                   status, poll_timeout, tmp);
#endif  
            if(via[B] & TREQ)
                break;
    
            /* ACK on-off */
            via[B] |= TACK;
            udelay(ADB_DELAY);
            via[B] &= ~TACK;
        }

        /* end frame */
        via[B] &= ~TIP;
        udelay(ADB_DELAY);
    }

    via[IER] = IER_SET | SR_INT;    
}

/* All specifically VIA-related initialization goes here */
static int
maciisi_init_via(void)
{
    int i;
    
    /* Set the lines up. We want TREQ as input TACK|TIP as output */
    via[DIRB] = (via[DIRB] | TACK | TIP) & ~TREQ;
    /* Shift register on input */
    via[ACR]  = (via[ACR] & ~SR_CTRL) | SR_EXT;
#ifdef DEBUG_MACIISI_ADB
    printk(KERN_DEBUG "maciisi_init_via: initial status %x\n", via[B] & (TIP|TREQ));
#endif
    /* Wipe any pending data and int */
    tmp = via[SR];
    /* Enable keyboard interrupts */
    via[IER] = IER_SET | SR_INT;
    /* Set initial state: idle */
    via[B] &= ~(TACK|TIP);
    /* Clear interrupt bit */
    via[IFR] = SR_INT;

    for(i = 0; i < 60; i++) {
        udelay(ADB_DELAY);
        maciisi_stfu();
        udelay(ADB_DELAY);
        if(via[B] & TREQ)
            break;
    }
    if (i == 60)
        printk(KERN_ERR "maciisi_init_via: bus jam?\n");

    maciisi_state = idle;
    need_sync = 0;

    return 0;
}

/* Send a request, possibly waiting for a reply */
static int
maciisi_send_request(struct adb_request* req, int sync)
{
    int i;

#ifdef DEBUG_MACIISI_ADB
    static int dump_packet = 0;
#endif

    if (via == NULL) {
        req->complete = 1;
        return -ENXIO;
    }

#ifdef DEBUG_MACIISI_ADB
    if (dump_packet) {
        printk(KERN_DEBUG "maciisi_send_request:");
        for (i = 0; i < req->nbytes; i++) {
            printk(" %.2x", req->data[i]);
        }
        printk(" sync %d\n", sync);
    }
#endif

    req->reply_expected = 1;
    
    i = maciisi_write(req);
    if (i)
    {
        /* Normally, if a packet requires syncing, that happens at the end of
         * maciisi_send_request. But if the transfer fails, it will be restarted
         * by maciisi_interrupt(). We use need_sync to tell maciisi_interrupt
         * when to sync a packet that it sends out.
         * 
         * Suggestions on a better way to do this are welcome.
         */
        if(i == -EBUSY && sync)
            need_sync = 1;
        else
            need_sync = 0;
        return i;
    }
    if(sync)
        maciisi_sync(req);
    
    return 0;
}

/* Poll the ADB chip until the request completes */
static void maciisi_sync(struct adb_request *req)
{
    int count = 0; 

#ifdef DEBUG_MACIISI_ADB
    printk(KERN_DEBUG "maciisi_sync called\n");
#endif

    /* If for some reason the ADB chip shuts up on us, we want to avoid an endless loop. */
    while (!req->complete && count++ < 50) {
        maciisi_poll();
    }
    /* This could be BAD... when the ADB controller doesn't respond
     * for this long, it's probably not coming back :-( */
    if (count > 50) /* Hopefully shouldn't happen */
        printk(KERN_ERR "maciisi_send_request: poll timed out!\n");
}

int
maciisi_request(struct adb_request *req, void (*done)(struct adb_request *),
        int nbytes, ...)
{
    va_list list;
    int i;

    req->nbytes = nbytes;
    req->done = done;
    req->reply_expected = 0;
    va_start(list, nbytes);
    for (i = 0; i < nbytes; i++)
        req->data[i++] = va_arg(list, int);
    va_end(list);

    return maciisi_send_request(req, 1);
}

/* Enqueue a request, and run the queue if possible */
static int
maciisi_write(struct adb_request* req)
{
    unsigned long flags;
    int i;

    /* We will accept CUDA packets - the VIA sends them to us, so
           it figures that we should be able to send them to it */
    if (req->nbytes < 2 || req->data[0] > CUDA_PACKET) {
        printk(KERN_ERR "maciisi_write: packet too small or not an ADB or CUDA packet\n");
        req->complete = 1;
        return -EINVAL;
    }
    req->next = NULL;
    req->sent = 0;
    req->complete = 0;
    req->reply_len = 0;
    
    local_irq_save(flags);

    if (current_req) {
        last_req->next = req;
        last_req = req;
    } else {
        current_req = req;
        last_req = req;
    }
    if (maciisi_state == idle)
    {
        i = maciisi_start();
        if(i != 0)
        {
            local_irq_restore(flags);
            return i;
        }
    }
    else
    {
#ifdef DEBUG_MACIISI_ADB
        printk(KERN_DEBUG "maciisi_write: would start, but state is %d\n", maciisi_state);
#endif
        local_irq_restore(flags);
        return -EBUSY;
    }

    local_irq_restore(flags);

    return 0;
}

static int
maciisi_start(void)
{
    struct adb_request* req;
    int status;

#ifdef DEBUG_MACIISI_ADB
    status = via[B] & (TIP | TREQ);

    printk(KERN_DEBUG "maciisi_start called, state=%d, status=%x, ifr=%x\n", maciisi_state, status, via[IFR]);
#endif

    if (maciisi_state != idle) {
        /* shouldn't happen */
        printk(KERN_ERR "maciisi_start: maciisi_start called when driver busy!\n");
        return -EBUSY;
    }

    req = current_req;
    if (req == NULL)
        return -EINVAL;

    status = via[B] & (TIP|TREQ);
    if (!(status & TREQ)) {
#ifdef DEBUG_MACIISI_ADB
        printk(KERN_DEBUG "maciisi_start: bus busy - aborting\n");
#endif
        return -EBUSY;
    }

    /* Okay, send */
#ifdef DEBUG_MACIISI_ADB
    printk(KERN_DEBUG "maciisi_start: sending\n");
#endif
    /* Set state to active */
    via[B] |= TIP;
    /* ACK off */
    via[B] &= ~TACK;
    /* Delay */
    udelay(ADB_DELAY);
    /* Shift out and send */
    via[ACR] |= SR_OUT;
    via[SR] = req->data[0];
    data_index = 1;
    /* ACK on */
    via[B] |= TACK;
    maciisi_state = sending;

    return 0;
}

void
maciisi_poll(void)
{
    unsigned long flags;

    local_irq_save(flags);
    if (via[IFR] & SR_INT) {
        maciisi_interrupt(0, NULL);
    }
    else /* avoid calling this function too quickly in a loop */
        udelay(ADB_DELAY);

    local_irq_restore(flags);
}

/* Shift register interrupt - this is *supposed* to mean that the
   register is either full or empty. In practice, I have no idea what
   it means :( */
static irqreturn_t
maciisi_interrupt(int irq, void* arg)
{
    int status;
    struct adb_request *req;
#ifdef DEBUG_MACIISI_ADB
    static int dump_reply = 0;
#endif
    int i;
    unsigned long flags;

    local_irq_save(flags);

    status = via[B] & (TIP|TREQ);
#ifdef DEBUG_MACIISI_ADB
    printk(KERN_DEBUG "state %d status %x ifr %x\n", maciisi_state, status, via[IFR]);
#endif

    if (!(via[IFR] & SR_INT)) {
        /* Shouldn't happen, we hope */
        printk(KERN_ERR "maciisi_interrupt: called without interrupt flag set\n");
        local_irq_restore(flags);
        return IRQ_NONE;
    }

    /* Clear the interrupt */
    /* via[IFR] = SR_INT; */

 switch_start:
    switch (maciisi_state) {
    case idle:
        if (status & TIP)
            printk(KERN_ERR "maciisi_interrupt: state is idle but TIP asserted!\n");

        if(!reading_reply)
            udelay(ADB_DELAY);
        /* Shift in */
        via[ACR] &= ~SR_OUT;
        /* Signal start of frame */
        via[B] |= TIP;
        /* Clear the interrupt (throw this value on the floor, it's useless) */
        tmp = via[SR];
        /* ACK adb chip, high-low */
        via[B] |= TACK;
        udelay(ADB_DELAY);
        via[B] &= ~TACK;
        reply_len = 0;
        maciisi_state = reading;
        if (reading_reply) {
            reply_ptr = current_req->reply;
        } else {
            reply_ptr = maciisi_rbuf;
        }
        break;

    case sending:
        /* via[SR]; */
        /* Set ACK off */
        via[B] &= ~TACK;
        req = current_req;

        if (!(status & TREQ)) {
            /* collision */
            printk(KERN_ERR "maciisi_interrupt: send collision\n");
            /* Set idle and input */
            via[ACR] &= ~SR_OUT;
            tmp = via[SR];
            via[B] &= ~TIP;
            /* Must re-send */
            reading_reply = 0;
            reply_len = 0;
            maciisi_state = idle;
            udelay(ADB_DELAY);
            /* process this now, because the IFR has been cleared */
            goto switch_start;
        }

        udelay(ADB_DELAY);

        if (data_index >= req->nbytes) {
            /* Sent the whole packet, put the bus back in idle state */
            /* Shift in, we are about to read a reply (hopefully) */
            via[ACR] &= ~SR_OUT;
            tmp = via[SR];
            /* End of frame */
            via[B] &= ~TIP;
            req->sent = 1;
            maciisi_state = idle;
            if (req->reply_expected) {
                /* Note: only set this once we've
                                   successfully sent the packet */
                reading_reply = 1;
            } else {
                current_req = req->next;
                if (req->done)
                    (*req->done)(req);
                /* Do any queued requests now */
                i = maciisi_start();
                if(i == 0 && need_sync) {
                    /* Packet needs to be synced */
                    maciisi_sync(current_req);
                }
                if(i != -EBUSY)
                    need_sync = 0;
            }
        } else {
            /* Sending more stuff */
            /* Shift out */
            via[ACR] |= SR_OUT;
            /* Write */
            via[SR] = req->data[data_index++];
            /* Signal 'byte ready' */
            via[B] |= TACK;
        }
        break;

    case reading:
        /* Shift in */
        /* via[ACR] &= ~SR_OUT; */ /* Not in 2.2 */
        if (reply_len++ > 16) {
            printk(KERN_ERR "maciisi_interrupt: reply too long, aborting read\n");
            via[B] |= TACK;
            udelay(ADB_DELAY);
            via[B] &= ~(TACK|TIP);
            maciisi_state = idle;
            i = maciisi_start();
            if(i == 0 && need_sync) {
                /* Packet needs to be synced */
                maciisi_sync(current_req);
            }
            if(i != -EBUSY)
                need_sync = 0;
            break;
        }
        /* Read data */
        *reply_ptr++ = via[SR];
        status = via[B] & (TIP|TREQ);
        /* ACK on/off */
        via[B] |= TACK;
        udelay(ADB_DELAY);
        via[B] &= ~TACK;    
        if (!(status & TREQ))
            break; /* more stuff to deal with */
        
        /* end of frame */
        via[B] &= ~TIP;
        tmp = via[SR]; /* That's what happens in 2.2 */
        udelay(ADB_DELAY); /* Give controller time to recover */

        /* end of packet, deal with it */
        if (reading_reply) {
            req = current_req;
            req->reply_len = reply_ptr - req->reply;
            if (req->data[0] == ADB_PACKET) {
                /* Have to adjust the reply from ADB commands */
                if (req->reply_len <= 2 || (req->reply[1] & 2) != 0) {
                    /* the 0x2 bit indicates no response */
                    req->reply_len = 0;
                } else {
                    /* leave just the command and result bytes in the reply */
                    req->reply_len -= 2;
                    memmove(req->reply, req->reply + 2, req->reply_len);
                }
            }
#ifdef DEBUG_MACIISI_ADB
            if (dump_reply) {
                int i;
                printk(KERN_DEBUG "maciisi_interrupt: reply is ");
                for (i = 0; i < req->reply_len; ++i)
                    printk(" %.2x", req->reply[i]);
                printk("\n");
            }
#endif
            req->complete = 1;
            current_req = req->next;
            if (req->done)
                (*req->done)(req);
            /* Obviously, we got it */
            reading_reply = 0;
        } else {
            maciisi_input(maciisi_rbuf, reply_ptr - maciisi_rbuf);
        }
        maciisi_state = idle;
        status = via[B] & (TIP|TREQ);
        if (!(status & TREQ)) {
            /* Timeout?! More likely, another packet coming in already */
#ifdef DEBUG_MACIISI_ADB
            printk(KERN_DEBUG "extra data after packet: status %x ifr %x\n",
                   status, via[IFR]);
#endif
#if 0
            udelay(ADB_DELAY);
            via[B] |= TIP;

            maciisi_state = reading;
            reading_reply = 0;
            reply_ptr = maciisi_rbuf;
#else
            /* Process the packet now */
            reading_reply = 0;
            goto switch_start;
#endif
            /* We used to do this... but the controller might actually have data for us */
            /* maciisi_stfu(); */
        }
        else {
            /* Do any queued requests now if possible */
            i = maciisi_start();
            if(i == 0 && need_sync) {
                /* Packet needs to be synced */
                maciisi_sync(current_req);
            }
            if(i != -EBUSY)
                need_sync = 0;
        }
        break;

    default:
        printk("maciisi_interrupt: unknown maciisi_state %d?\n", maciisi_state);
    }
    local_irq_restore(flags);
    return IRQ_HANDLED;
}

static void
maciisi_input(unsigned char *buf, int nb)
{
#ifdef DEBUG_MACIISI_ADB
    int i;
#endif

    switch (buf[0]) {
    case ADB_PACKET:
        adb_input(buf+2, nb-2, buf[1] & 0x40);
        break;
    default:
#ifdef DEBUG_MACIISI_ADB
        printk(KERN_DEBUG "data from IIsi ADB (%d bytes):", nb);
        for (i = 0; i < nb; ++i)
            printk(" %.2x", buf[i]);
        printk("\n");
#endif
        break;
    }
}