From: Mark Lord Date: Thu, 21 Feb 2008 20:52:25 +0000 (-0500) Subject: libata-pmp: clear hob for pmp register accesses X-Git-Tag: v2.6.25-rc3~8^2~3 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=39f25e70ca37b8a719e8274e6f3ec2ce2ea8df04;p=platform%2Fkernel%2Flinux-stable.git libata-pmp: clear hob for pmp register accesses >> Mark Lord wrote: >>> Tejun, I've added PMP to sata_mv, and am now trying to get it >>> to work with a Marvell PM attached. >>> >>> And the behaviour I see is very bizarre. >>> >>> After hard+soft resets, the PM signature is found, >>> and libata interrogates the PM registers. >>> >>> It successfully reads register 0, and then register 1. >>> But all subsequent registers read out (incorrectly) as zeros. ... This behavior has been confirmed by Marvell with a SATA analyzer. The Marvell port-multiplier apparently likes to see clean HOB information when accessing PMP registers. Since sata_mv uses PIO shadow register access, this doesn't happen automatically, as it might in a more purely FIS-based driver (eg. ahci). One way to fix this is to flag these commands with ATA_TFLAG_LBA48, forcing libata to write out the HOB fields with known (zero) values. Signed-off-by: Saeed Bishara Acked-by: Mark Lord Signed-off-by: Jeff Garzik --- diff --git a/drivers/ata/libata-pmp.c b/drivers/ata/libata-pmp.c index caef2bb..d91f509 100644 --- a/drivers/ata/libata-pmp.c +++ b/drivers/ata/libata-pmp.c @@ -35,7 +35,7 @@ static unsigned int sata_pmp_read(struct ata_link *link, int reg, u32 *r_val) ata_tf_init(pmp_dev, &tf); tf.command = ATA_CMD_PMP_READ; tf.protocol = ATA_PROT_NODATA; - tf.flags |= ATA_TFLAG_ISADDR | ATA_TFLAG_DEVICE; + tf.flags |= ATA_TFLAG_ISADDR | ATA_TFLAG_DEVICE | ATA_TFLAG_LBA48; tf.feature = reg; tf.device = link->pmp; @@ -71,7 +71,7 @@ static unsigned int sata_pmp_write(struct ata_link *link, int reg, u32 val) ata_tf_init(pmp_dev, &tf); tf.command = ATA_CMD_PMP_WRITE; tf.protocol = ATA_PROT_NODATA; - tf.flags |= ATA_TFLAG_ISADDR | ATA_TFLAG_DEVICE; + tf.flags |= ATA_TFLAG_ISADDR | ATA_TFLAG_DEVICE | ATA_TFLAG_LBA48; tf.feature = reg; tf.device = link->pmp; tf.nsect = val & 0xff;