[PATCH] libata: flush COMRESET set and clear
Updated patch to fix erroneous flush of COMRESET set and missing flush
of COMRESET clear. Created a new routine scr_write_flush() to try to
prevent this in the future. Also, this patch is based on libata-2.6
instead of the previous libata-dev-2.6 based patch.
Signed-off-by: Brett Russ <russb@emc.com>
Index: libata-2.6/drivers/scsi/libata-core.c
===================================================================
diff --git a/drivers/scsi/libata-core.c b/drivers/scsi/libata-core.c
index f70935c..ee9b96d 100644
--- a/drivers/scsi/libata-core.c
+++ b/drivers/scsi/libata-core.c
@@ -1253,11 +1253,11 @@
unsigned long timeout = jiffies + (HZ * 5);
if (ap->flags & ATA_FLAG_SATA_RESET) {
- scr_write(ap, SCR_CONTROL, 0x301); /* issue phy wake/reset */
- scr_read(ap, SCR_STATUS); /* dummy read; flush */
+ /* issue phy wake/reset */
+ scr_write_flush(ap, SCR_CONTROL, 0x301);
udelay(400); /* FIXME: a guess */
}
- scr_write(ap, SCR_CONTROL, 0x300); /* issue phy wake/clear reset */
+ scr_write_flush(ap, SCR_CONTROL, 0x300); /* phy wake/clear reset */
/* wait for phy to become ready, if necessary */
do {
diff --git a/include/linux/libata.h b/include/linux/libata.h
index 505160a..1f7e203 100644
--- a/include/linux/libata.h
+++ b/include/linux/libata.h
@@ -584,6 +584,13 @@
ap->ops->scr_write(ap, reg, val);
}
+static inline void scr_write_flush(struct ata_port *ap, unsigned int reg,
+ u32 val)
+{
+ ap->ops->scr_write(ap, reg, val);
+ (void) ap->ops->scr_read(ap, reg);
+}
+
static inline unsigned int sata_dev_present(struct ata_port *ap)
{
return ((scr_read(ap, SCR_STATUS) & 0xf) == 0x3) ? 1 : 0;