pdc4030.c

at91rm9200处理器ide接口驱动程序源代码

void __init ide_probe_for_pdc4030(void)
{
	unsigned int	index;
	ide_hwif_t	*hwif;

	if (enable_promise_support == 0)
		return;
	for (index = 0; index < MAX_HWIFS; index++) {
		hwif = &ide_hwifs[index];
		if (hwif->chipset == ide_unknown && detect_pdc4030(hwif)) {
			setup_pdc4030(hwif);
		}
	}
}

/*
 * promise_read_intr() is the handler for disk read/multread interrupts
 */
static ide_startstop_t promise_read_intr (ide_drive_t *drive)
{
	byte stat;
	int total_remaining;
	unsigned int sectors_left, sectors_avail, nsect;
	struct request *rq;

	if (!OK_STAT(stat=GET_STAT(),DATA_READY,BAD_R_STAT)) {
		return ide_error(drive, "promise_read_intr", stat);
	}

read_again:
	do {
		sectors_left = IN_BYTE(IDE_NSECTOR_REG);
		IN_BYTE(IDE_SECTOR_REG);
	} while (IN_BYTE(IDE_NSECTOR_REG) != sectors_left);
	rq = HWGROUP(drive)->rq;
	sectors_avail = rq->nr_sectors - sectors_left;
	if (!sectors_avail)
		goto read_again;

read_next:
	rq = HWGROUP(drive)->rq;
	nsect = rq->current_nr_sectors;
	if (nsect > sectors_avail)
		nsect = sectors_avail;
	sectors_avail -= nsect;
	ide_input_data(drive, rq->buffer, nsect * SECTOR_WORDS);
#ifdef DEBUG_READ
	printk(KERN_DEBUG "%s:  promise_read: sectors(%ld-%ld), "
	       "buf=0x%08lx, rem=%ld\n", drive->name, rq->sector,
	       rq->sector+nsect-1, (unsigned long) rq->buffer,
	       rq->nr_sectors-nsect);
#endif
	rq->sector += nsect;
	rq->buffer += nsect<<9;
	rq->errors = 0;
	rq->nr_sectors -= nsect;
	total_remaining = rq->nr_sectors;
	if ((rq->current_nr_sectors -= nsect) <= 0) {
		ide_end_request(1, HWGROUP(drive));
	}
/*
 * Now the data has been read in, do the following:
 * 
 * if there are still sectors left in the request, 
 *   if we know there are still sectors available from the interface,
 *     go back and read the next bit of the request.
 *   else if DRQ is asserted, there are more sectors available, so
 *     go back and find out how many, then read them in.
 *   else if BUSY is asserted, we are going to get an interrupt, so
 *     set the handler for the interrupt and just return
 */
	if (total_remaining > 0) {
		if (sectors_avail)
			goto read_next;
		stat = GET_STAT();
		if (stat & DRQ_STAT)
			goto read_again;
		if (stat & BUSY_STAT) {
			ide_set_handler (drive, &promise_read_intr, WAIT_CMD, NULL);
#ifdef DEBUG_READ
			printk(KERN_DEBUG "%s: promise_read: waiting for"
			       "interrupt\n", drive->name);
#endif
			return ide_started;
		}
		printk(KERN_ERR "%s: Eeek! promise_read_intr: sectors left "
		       "!DRQ !BUSY\n", drive->name);
		return ide_error(drive, "promise read intr", stat);
	}
	return ide_stopped;
}

/*
 * promise_complete_pollfunc()
 * This is the polling function for waiting (nicely!) until drive stops
 * being busy. It is invoked at the end of a write, after the previous poll
 * has finished.
 *
 * Once not busy, the end request is called.
 */
static ide_startstop_t promise_complete_pollfunc(ide_drive_t *drive)
{
	ide_hwgroup_t *hwgroup = HWGROUP(drive);
	struct request *rq = hwgroup->rq;
	int i;

	if (GET_STAT() & BUSY_STAT) {
		if (time_before(jiffies, hwgroup->poll_timeout)) {
			ide_set_handler(drive, &promise_complete_pollfunc, HZ/100, NULL);
			return ide_started; /* continue polling... */
		}
		hwgroup->poll_timeout = 0;
		printk(KERN_ERR "%s: completion timeout - still busy!\n",
		       drive->name);
		return ide_error(drive, "busy timeout", GET_STAT());
	}

	hwgroup->poll_timeout = 0;
#ifdef DEBUG_WRITE
	printk(KERN_DEBUG "%s: Write complete - end_request\n", drive->name);
#endif
	for (i = rq->nr_sectors; i > 0; ) {
		i -= rq->current_nr_sectors;
		ide_end_request(1, hwgroup);
	}
	return ide_stopped;
}

/*
 * promise_write_pollfunc() is the handler for disk write completion polling.
 */
static ide_startstop_t promise_write_pollfunc (ide_drive_t *drive)
{
	ide_hwgroup_t *hwgroup = HWGROUP(drive);

	if (IN_BYTE(IDE_NSECTOR_REG) != 0) {
		if (time_before(jiffies, hwgroup->poll_timeout)) {
			ide_set_handler (drive, &promise_write_pollfunc, HZ/100, NULL);
			return ide_started; /* continue polling... */
		}
		hwgroup->poll_timeout = 0;
		printk(KERN_ERR "%s: write timed-out!\n",drive->name);
		return ide_error (drive, "write timeout", GET_STAT());
	}

	/*
	 * Now write out last 4 sectors and poll for not BUSY
	 */
	ide_multwrite(drive, 4);
	hwgroup->poll_timeout = jiffies + WAIT_WORSTCASE;
	ide_set_handler(drive, &promise_complete_pollfunc, HZ/100, NULL);
#ifdef DEBUG_WRITE
	printk(KERN_DEBUG "%s: Done last 4 sectors - status = %02x\n",
		drive->name, GET_STAT());
#endif
	return ide_started;
}

/*
 * promise_write() transfers a block of one or more sectors of data to a
 * drive as part of a disk write operation. All but 4 sectors are transferred
 * in the first attempt, then the interface is polled (nicely!) for completion
 * before the final 4 sectors are transferred. There is no interrupt generated
 * on writes (at least on the DC4030VL-2), we just have to poll for NOT BUSY.
 */
static ide_startstop_t promise_write (ide_drive_t *drive)
{
	ide_hwgroup_t *hwgroup = HWGROUP(drive);
	struct request *rq = &hwgroup->wrq;

#ifdef DEBUG_WRITE
	printk(KERN_DEBUG "%s: promise_write: sectors(%ld-%ld), "
	       "buffer=%p\n", drive->name, rq->sector,
	       rq->sector + rq->nr_sectors - 1, rq->buffer);
#endif

	/*
	 * If there are more than 4 sectors to transfer, do n-4 then go into
	 * the polling strategy as defined above.
	 */
	if (rq->nr_sectors > 4) {
		if (ide_multwrite(drive, rq->nr_sectors - 4))
			return ide_stopped;
		hwgroup->poll_timeout = jiffies + WAIT_WORSTCASE;
		ide_set_handler (drive, &promise_write_pollfunc, HZ/100, NULL);
		return ide_started;
	} else {
	/*
	 * There are 4 or fewer sectors to transfer, do them all in one go
	 * and wait for NOT BUSY.
	 */
		if (ide_multwrite(drive, rq->nr_sectors))
			return ide_stopped;
		hwgroup->poll_timeout = jiffies + WAIT_WORSTCASE;
		ide_set_handler(drive, &promise_complete_pollfunc, HZ/100, NULL);
#ifdef DEBUG_WRITE
		printk(KERN_DEBUG "%s: promise_write: <= 4 sectors, "
			"status = %02x\n", drive->name, GET_STAT());
#endif
		return ide_started;
	}
}

/*
 * do_pdc4030_io() is called from do_rw_disk, having had the block number
 * already set up. It issues a READ or WRITE command to the Promise
 * controller, assuming LBA has been used to set up the block number.
 */
ide_startstop_t do_pdc4030_io (ide_drive_t *drive, struct request *rq)
{
	ide_startstop_t startstop;
	unsigned long timeout;
	byte stat;

	switch(rq->cmd) {
		case READ:
#ifndef __TASKFILE__IO
			OUT_BYTE(PROMISE_READ, IDE_COMMAND_REG);
#endif
/*
 * The card's behaviour is odd at this point. If the data is
 * available, DRQ will be true, and no interrupt will be
 * generated by the card. If this is the case, we need to call the 
 * "interrupt" handler (promise_read_intr) directly. Otherwise, if
 * an interrupt is going to occur, bit0 of the SELECT register will
 * be high, so we can set the handler the just return and be interrupted.
 * If neither of these is the case, we wait for up to 50ms (badly I'm
 * afraid!) until one of them is.
 */
			timeout = jiffies + HZ/20; /* 50ms wait */
			do {
				stat=GET_STAT();
				if (stat & DRQ_STAT) {
					udelay(1);
					return promise_read_intr(drive);
				}
				if (IN_BYTE(IDE_SELECT_REG) & 0x01) {
#ifdef DEBUG_READ
	printk(KERN_DEBUG "%s: read: waiting for interrupt\n", drive->name);
#endif
					ide_set_handler(drive, &promise_read_intr, WAIT_CMD, NULL);
					return ide_started;
				}
				udelay(1);
			} while (time_before(jiffies, timeout));

			printk(KERN_ERR "%s: reading: No DRQ and not waiting - Odd!\n", drive->name);
			return ide_stopped;
		case WRITE:
#ifndef __TASKFILE__IO
			OUT_BYTE(PROMISE_WRITE, IDE_COMMAND_REG);
#endif
			if (ide_wait_stat(&startstop, drive, DATA_READY, drive->bad_wstat, WAIT_DRQ)) {
				printk(KERN_ERR "%s: no DRQ after issuing PROMISE_WRITE\n", drive->name);
				return startstop;
		    	}
			if (!drive->unmask)
				__cli();	/* local CPU only */
			HWGROUP(drive)->wrq = *rq; /* scratchpad */
			return promise_write(drive);
		default:
			printk("KERN_WARNING %s: bad command: %d\n", drive->name, rq->cmd);
			ide_end_request(0, HWGROUP(drive));
			return ide_stopped;
	}
}

#ifdef __TASKFILE__IO

ide_startstop_t promise_rw_disk (ide_drive_t *drive, struct request *rq, unsigned long block)
{
	struct hd_drive_task_hdr taskfile;

	memset(&taskfile, 0, sizeof(struct hd_drive_task_hdr));

	taskfile.sector_count	= rq->nr_sectors;
	taskfile.sector_number	= block;
	taskfile.low_cylinder	= (block>>=8);
	taskfile.high_cylinder	= (block>>=8);
	taskfile.device_head	= ((block>>8)&0x0f)|drive->select.all;
	taskfile.command	= (rq->cmd==READ)?PROMISE_READ:PROMISE_WRITE;

	do_taskfile(drive, &taskfile, NULL, NULL);
	return do_pdc4030_io(drive, rq);
}
#endif