pdc4030.c

来自「Linux Kernel 2.6.9 for OMAP1710」· C语言 代码 · 共 680 行 · 第 1/2 页

		goto read_again;

read_next:
	nsect = rq->current_nr_sectors;
	if (nsect > sectors_avail)
		nsect = sectors_avail;
	sectors_avail -= nsect;

#ifdef DEBUG_READ
	printk(KERN_DEBUG "%s: %s: sectors(%lu-%lu), rem=%lu\n",
			  drive->name, __FUNCTION__,
			  (unsigned long)rq->sector,
			  (unsigned long)rq->sector + nsect - 1,
			  (unsigned long)rq->nr_sectors - nsect);
#endif /* DEBUG_READ */

	HWIF(drive)->ata_input_data(drive, rq->buffer, nsect * SECTOR_WORDS);
	rq->buffer += nsect<<9;
	rq->sector += nsect;
	rq->errors = 0;
	rq->nr_sectors -= nsect;
	if (!rq->current_nr_sectors)
		DRIVER(drive)->end_request(drive, 1, 0);

/*
 * 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 (rq->nr_sectors > 0) {
		if (sectors_avail)
			goto read_next;
		status.all = HWIF(drive)->INB(IDE_STATUS_REG);
		if (status.b.drq)
			goto read_again;
		if (status.b.bsy) {
			if (HWGROUP(drive)->handler != NULL)
				BUG();
			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 /* DEBUG_READ */
			return ide_started;
		}
		printk(KERN_ERR "%s: Eeek! promise_read_intr: sectors left "
		       "!DRQ !BUSY\n", drive->name);
		return DRIVER(drive)->error(drive,
				"promise read intr", status.all);
	}
	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->wrq;
	struct bio *bio = rq->bio;

	if ((HWIF(drive)->INB(IDE_STATUS_REG)) & BUSY_STAT) {
		if (time_before(jiffies, hwgroup->poll_timeout)) {
			if (hwgroup->handler != NULL)
				BUG();
			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 DRIVER(drive)->error(drive, "busy timeout",
				HWIF(drive)->INB(IDE_STATUS_REG));
	}

	hwgroup->poll_timeout = 0;
#ifdef DEBUG_WRITE
	printk(KERN_DEBUG "%s: Write complete - end_request\n", drive->name);
#endif /* DEBUG_WRITE */

	bio->bi_idx = bio->bi_vcnt - rq->nr_cbio_segments;
	rq = hwgroup->rq;
	DRIVER(drive)->end_request(drive, 1, rq->hard_nr_sectors);

	return ide_stopped;
}

/*
 * promise_multwrite() transfers a block of up to mcount sectors of data
 * to a drive as part of a disk multiple-sector write operation.
 */
static void promise_multwrite (ide_drive_t *drive, unsigned int mcount)
{
	ide_hwgroup_t *hwgroup	= HWGROUP(drive);
	struct request *rq	= &hwgroup->wrq;

	do {
		char *buffer;
		int nsect = rq->current_nr_sectors;

		if (nsect > mcount)
			nsect = mcount;
		mcount -= nsect;
		buffer = rq->buffer;

		rq->sector += nsect;
		rq->buffer += nsect << 9;
		rq->nr_sectors -= nsect;
		rq->current_nr_sectors -= nsect;

		/* Do we move to the next bh after this? */
		if (!rq->current_nr_sectors) {
			struct bio *bio = rq->bio;

			/*
			 * only move to next bio, when we have processed
			 * all bvecs in this one.
			 */
			if (++bio->bi_idx >= bio->bi_vcnt) {
				bio->bi_idx = bio->bi_vcnt - rq->nr_cbio_segments;
				bio = bio->bi_next;
			}

			/* end early early we ran out of requests */
			if (!bio) {
				mcount = 0;
			} else {
				rq->bio = bio;
				rq->nr_cbio_segments = bio_segments(bio);
				rq->current_nr_sectors = bio_cur_sectors(bio);
				rq->hard_cur_sectors = rq->current_nr_sectors;
			}
		}

		/*
		 * Ok, we're all setup for the interrupt
		 * re-entering us on the last transfer.
		 */
		taskfile_output_data(drive, buffer, nsect<<7);
	} while (mcount);
}

/*
 * 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);
	struct request *rq = &hwgroup->wrq;
	struct bio *bio = rq->bio;

	if (HWIF(drive)->INB(IDE_NSECTOR_REG) != 0) {
		if (time_before(jiffies, hwgroup->poll_timeout)) {
			if (hwgroup->handler != NULL)
				BUG();
			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);
		bio->bi_idx = bio->bi_vcnt - rq->nr_cbio_segments;
		return DRIVER(drive)->error(drive, "write timeout",
				HWIF(drive)->INB(IDE_STATUS_REG));
	}

	/*
	 * Now write out last 4 sectors and poll for not BUSY
	 */
	promise_multwrite(drive, 4);
	hwgroup->poll_timeout = jiffies + WAIT_WORSTCASE;
	if (hwgroup->handler != NULL)
		BUG();
	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, HWIF(drive)->INB(IDE_STATUS_REG));
#endif /* DEBUG_WRITE */
	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: %s: sectors(%lu-%lu)\n",
			  drive->name, __FUNCTION__,
			  (unsigned long)rq->sector,
			  (unsigned long)rq->sector + rq->nr_sectors - 1);
#endif /* DEBUG_WRITE */

	/*
	 * 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) {
		promise_multwrite(drive, rq->nr_sectors - 4);
		hwgroup->poll_timeout = jiffies + WAIT_WORSTCASE;
		if (hwgroup->handler != NULL)	/* paranoia check */
			BUG();
		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.
	 */
		promise_multwrite(drive, rq->nr_sectors);
		hwgroup->poll_timeout = jiffies + WAIT_WORSTCASE;
		if (hwgroup->handler != NULL)
			BUG();
		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,
			HWIF(drive)->INB(IDE_STATUS_REG));
#endif /* DEBUG_WRITE */
		return ide_started;
	}
}

/*
 * do_pdc4030_io() is called from promise_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;
	u8 stat = 0;

	if (rq_data_dir(rq) == READ) {
		HWIF(drive)->OUTB(PROMISE_READ, IDE_COMMAND_REG);
/*
 * 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 = HWIF(drive)->INB(IDE_STATUS_REG);
			if (stat & DRQ_STAT) {
				udelay(1);
				return promise_read_intr(drive);
			}
			if (HWIF(drive)->INB(IDE_SELECT_REG) & 0x01) {
#ifdef DEBUG_READ
				printk(KERN_DEBUG "%s: read: waiting for "
						"interrupt\n", drive->name);
#endif /* DEBUG_READ */
				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;
	} else {
		HWIF(drive)->OUTB(PROMISE_WRITE, IDE_COMMAND_REG);
		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)
			local_irq_disable();
		HWGROUP(drive)->wrq = *rq; /* scratchpad */
		return promise_write(drive);
	}
}

static ide_startstop_t promise_rw_disk (ide_drive_t *drive, struct request *rq, sector_t block)
{
	/* The four drives on the two logical (one physical) interfaces
	   are distinguished by writing the drive number (0-3) to the
	   Feature register.
	   FIXME: Is promise_selectproc now redundant??
	*/
	ide_hwif_t *hwif = HWIF(drive);
	int drive_number = (hwif->channel << 1) + drive->select.b.unit;

	BUG_ON(rq->nr_sectors > 127);

	if (IDE_CONTROL_REG)
		hwif->OUTB(drive->ctl, IDE_CONTROL_REG);
	hwif->OUTB(drive_number, IDE_FEATURE_REG);
	hwif->OUTB(rq->nr_sectors, IDE_NSECTOR_REG);
	hwif->OUTB(block,IDE_SECTOR_REG);
	hwif->OUTB(block>>=8,IDE_LCYL_REG);
	hwif->OUTB(block>>=8,IDE_HCYL_REG);
	hwif->OUTB(((block>>8)&0x0f)|drive->select.all,IDE_SELECT_REG);

	return do_pdc4030_io(drive, rq);
}