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adb-iop.c

/*
 * I/O Processor (IOP) ADB Driver
 * Written and (C) 1999 by Joshua M. Thompson (funaho@jurai.org)
 * 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;
      uint 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;
      uint 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;
}

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