Commit cf176e1a authored by Tejun Heo's avatar Tejun Heo Committed by Jeff Garzik
Browse files

[PATCH] libata: implement ata_down_xfermask_limit() 



Implement ata_down_xfermask_limit().  This function manipulates
@dev->pio/mwdma/udma_mask such that the next lower transfer mode is
selected.  This will be used to improve ata_bus_probe() failure
handling and later by EH.

Signed-off-by: default avatarTejun Heo <htejun@gmail.com>
Signed-off-by: default avatarJeff Garzik <jeff@garzik.org>
parent edbabd86

drivers/scsi/libata-core.c

+52 −0
Original line number Diff line number Diff line
@@ -65,6 +65,8 @@ static unsigned int ata_dev_init_params(struct ata_port *ap, 
					struct ata_device *dev,

					u16 heads,

					u16 sectors);

static int ata_down_xfermask_limit(struct ata_port *ap, struct ata_device *dev,

				   int force_pio0);

static int ata_down_sata_spd_limit(struct ata_port *ap);

static int ata_set_mode(struct ata_port *ap, struct ata_device **r_failed_dev);

static unsigned int ata_dev_set_xfermode(struct ata_port *ap,
@@ -1859,6 +1861,56 @@ int ata_timing_compute(struct ata_device *adev, unsigned short speed, 
	return 0;

}



/**

 *	ata_down_xfermask_limit - adjust dev xfer masks downward

 *	@ap: Port associated with device @dev

 *	@dev: Device to adjust xfer masks

 *	@force_pio0: Force PIO0

 *

 *	Adjust xfer masks of @dev downward.  Note that this function

 *	does not apply the change.  Invoking ata_set_mode() afterwards

 *	will apply the limit.

 *

 *	LOCKING:

 *	Inherited from caller.

 *

 *	RETURNS:

 *	0 on success, negative errno on failure

 */

static int ata_down_xfermask_limit(struct ata_port *ap, struct ata_device *dev,

				   int force_pio0)

{

	unsigned long xfer_mask;

	int highbit;



	xfer_mask = ata_pack_xfermask(dev->pio_mask, dev->mwdma_mask,

				      dev->udma_mask);



	if (!xfer_mask)

		goto fail;

	/* don't gear down to MWDMA from UDMA, go directly to PIO */

	if (xfer_mask & ATA_MASK_UDMA)

		xfer_mask &= ~ATA_MASK_MWDMA;



	highbit = fls(xfer_mask) - 1;

	xfer_mask &= ~(1 << highbit);

	if (force_pio0)

		xfer_mask &= 1 << ATA_SHIFT_PIO;

	if (!xfer_mask)

		goto fail;



	ata_unpack_xfermask(xfer_mask, &dev->pio_mask, &dev->mwdma_mask,

			    &dev->udma_mask);



	printk(KERN_WARNING "ata%u: dev %u limiting speed to %s\n",

	       ap->id, dev->devno, ata_mode_string(xfer_mask));



	return 0;



 fail:

	return -EINVAL;

}



static int ata_dev_set_mode(struct ata_port *ap, struct ata_device *dev)

{

	unsigned int err_mask;