adb-iop.c

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/*
 * I/O Processor (IOP) ADB Driver
 * Written and (C) 1999 by Joshua M. Thompson ([email protected])
 * Based on via-cuda.c by Paul Mackerras.
 *
 * 1999-07-01 (jmt) - First implementation for new driver architecture.
 *
 * 1999-07-31 (jmt) - First working version.
 *
 * TODO:
 *
 * o Implement SRQ handling.
 */

#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/delay.h>
#include <linux/init.h>
#include <linux/proc_fs.h>

#include <asm/macintosh.h> 
#include <asm/macints.h> 
#include <asm/mac_iop.h>
#include <asm/mac_oss.h>
#include <asm/adb_iop.h>

#include <linux/adb.h> 

/*#define DEBUG_ADB_IOP*/

extern void iop_ism_irq(int, void *);

static struct adb_request *current_req;
static struct adb_request *last_req;
#if 0
static unsigned char reply_buff[16];
static unsigned char *reply_ptr;
#endif

static enum adb_iop_state {
    idle,
    sending,
    awaiting_reply
} adb_iop_state;

static void adb_iop_start(void);
static int adb_iop_probe(void);
static int adb_iop_init(void);
static int adb_iop_send_request(struct adb_request *, int);
static int adb_iop_write(struct adb_request *);
static int adb_iop_autopoll(int);
static void adb_iop_poll(void);
static int adb_iop_reset_bus(void);

struct adb_driver adb_iop_driver = {
    "ISM IOP",
    adb_iop_probe,
    adb_iop_init,
    adb_iop_send_request,
    adb_iop_autopoll,
    adb_iop_poll,
    adb_iop_reset_bus
};

static void adb_iop_end_req(struct adb_request *req, int state)
{
    req->complete = 1;
    current_req = req->next;
    if (req->done) (*req->done)(req);
    adb_iop_state = state;
}

/*
 * Completion routine for ADB commands sent to the IOP.
 *
 * This will be called when a packet has been successfully sent.
 */

static void adb_iop_complete(struct iop_msg *msg)
{
    struct adb_request *req;
    unsigned long flags;

    local_irq_save(flags);

    req = current_req;
    if ((adb_iop_state == sending) && req && req->reply_expected) {
        adb_iop_state = awaiting_reply;
    }

    local_irq_restore(flags);
}

/*
 * Listen for ADB messages from the IOP.
 *
 * This will be called when unsolicited messages (usually replies to TALK
 * commands or autopoll packets) are received.
 */

static void adb_iop_listen(struct iop_msg *msg)
{
    struct adb_iopmsg *amsg = (struct adb_iopmsg *) msg->message;
    struct adb_request *req;
    unsigned long flags;
#ifdef DEBUG_ADB_IOP
    int i;
#endif

    local_irq_save(flags);

    req = current_req;

#ifdef DEBUG_ADB_IOP
    printk("adb_iop_listen %p: rcvd packet, %d bytes: %02X %02X", req,
        (uint) amsg->count + 2, (uint) amsg->flags, (uint) amsg->cmd);
    for (i = 0; i < amsg->count; i++)
        printk(" %02X", (uint) amsg->data[i]);
    printk("\n");
#endif

    /* Handle a timeout. Timeout packets seem to occur even after */
    /* we've gotten a valid reply to a TALK, so I'm assuming that */
    /* a "timeout" is actually more like an "end-of-data" signal. */
    /* We need to send back a timeout packet to the IOP to shut   */
    /* it up, plus complete the current request, if any.          */

    if (amsg->flags & ADB_IOP_TIMEOUT) {
        msg->reply[0] = ADB_IOP_TIMEOUT | ADB_IOP_AUTOPOLL;
        msg->reply[1] = 0;
        msg->reply[2] = 0;
        if (req && (adb_iop_state != idle)) {
            adb_iop_end_req(req, idle);
        }
    } else {
        /* TODO: is it possible for more than one chunk of data  */
        /*       to arrive before the timeout? If so we need to */
        /*       use reply_ptr here like the other drivers do.  */
        if ((adb_iop_state == awaiting_reply) &&
            (amsg->flags & ADB_IOP_EXPLICIT)) {
            req->reply_len = amsg->count + 1;
            memcpy(req->reply, &amsg->cmd, req->reply_len);
        } else {
            adb_input(&amsg->cmd, amsg->count + 1,
                  amsg->flags & ADB_IOP_AUTOPOLL);
        }
        memcpy(msg->reply, msg->message, IOP_MSG_LEN);
    }
    iop_complete_message(msg);
    local_irq_restore(flags);
}

/*
 * Start sending an ADB packet, IOP style
 *
 * There isn't much to do other than hand the packet over to the IOP
 * after encapsulating it in an adb_iopmsg.
 */

static void adb_iop_start(void)
{
    unsigned long flags;
    struct adb_request *req;
    struct adb_iopmsg amsg;
#ifdef DEBUG_ADB_IOP
    int i;
#endif

    /* get the packet to send */
    req = current_req;
    if (!req) return;

    local_irq_save(flags);

#ifdef DEBUG_ADB_IOP
    printk("adb_iop_start %p: sending packet, %d bytes:", req, req->nbytes);
    for (i = 0 ; i < req->nbytes ; i++)
        printk(" %02X", (uint) req->data[i]);
    printk("\n");
#endif

    /* The IOP takes MacII-style packets, so */
    /* strip the initial ADB_PACKET byte.    */

    amsg.flags = ADB_IOP_EXPLICIT;
    amsg.count = req->nbytes - 2;

    /* amsg.data immediately follows amsg.cmd, effectively making */
    /* amsg.cmd a pointer to the beginning of a full ADB packet.  */
    memcpy(&amsg.cmd, req->data + 1, req->nbytes - 1);

    req->sent = 1;
    adb_iop_state = sending;
    local_irq_restore(flags);

    /* Now send it. The IOP manager will call adb_iop_complete */
    /* when the packet has been sent.                          */

    iop_send_message(ADB_IOP, ADB_CHAN, req,
             sizeof(amsg), (__u8 *) &amsg, adb_iop_complete);
}

int adb_iop_probe(void)
{
    if (!iop_ism_present) return -ENODEV;
    return 0;
}

int adb_iop_init(void)
{
    printk("adb: IOP ISM driver v0.4 for Unified ADB.\n");
    iop_listen(ADB_IOP, ADB_CHAN, adb_iop_listen, "ADB");
    return 0;
}

int adb_iop_send_request(struct adb_request *req, int sync)
{
    int err;

    err = adb_iop_write(req);
    if (err) return err;

    if (sync) {
        while (!req->complete) adb_iop_poll();
    }
    return 0;
}

static int adb_iop_write(struct adb_request *req)
{
    unsigned long flags;

    if ((req->nbytes < 2) || (req->data[0] != ADB_PACKET)) {
        req->complete = 1;
        return -EINVAL;
    }

    local_irq_save(flags);

    req->next = NULL;
    req->sent = 0;
    req->complete = 0;
    req->reply_len = 0;

    if (current_req != 0) {
        last_req->next = req;
        last_req = req;
    } else {
        current_req = req;
        last_req = req;
    }

    local_irq_restore(flags);
    if (adb_iop_state == idle) adb_iop_start();
    return 0;
}

int adb_iop_autopoll(int devs)
{
    /* TODO: how do we enable/disable autopoll? */
    return 0;
}

void adb_iop_poll(void)
{
    if (adb_iop_state == idle) adb_iop_start();
    iop_ism_irq(0, (void *) ADB_IOP);
}

int adb_iop_reset_bus(void)
{
    struct adb_request req = {
        .reply_expected = 0,
        .nbytes = 2,
        .data = { ADB_PACKET, 0 },
    };

    adb_iop_write(&req);
    while (!req.complete) {
        adb_iop_poll();
        schedule();
    }

    return 0;
}