/*
   * 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;
  	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("
  ");
  #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("
  ");
  #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.
  ");
  	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;
  }