sata_promise: add ATA engine reset to reset ops

Promise ATA engines need to be reset when errors occur.
That's currently done for errors detected by sata_promise itself,
but it's not done for errors like timeouts detected outside of
the low-level driver.

The effect of this omission is that a timeout tends to result
in a sequence of failed COMRESETs after which libata EH gives
up and disables the port. At that point the port's ATA engine
hangs and even reloading the driver will not resume it.

To fix this, make sata_promise override ->hardreset on SATA
ports with code which calls pdc_reset_port() on the port in
question before calling libata's hardreset. PATA ports don't
use ->hardreset, so for those we override ->softreset instead.
Signed-off-by: Mikael Pettersson <mikpe@it.uu.se>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>

drivers/ata/sata_promise.c

@@ -153,6 +153,10 @@ static void pdc_freeze(struct ata_port *ap);
 static void pdc_sata_freeze(struct ata_port *ap);
 static void pdc_thaw(struct ata_port *ap);
 static void pdc_sata_thaw(struct ata_port *ap);
+static int pdc_pata_softreset(struct ata_link *link, unsigned int *class,
+			      unsigned long deadline);
+static int pdc_sata_hardreset(struct ata_link *link, unsigned int *class,
+			      unsigned long deadline);
 static void pdc_error_handler(struct ata_port *ap);
 static void pdc_post_internal_cmd(struct ata_queued_cmd *qc);
 static int pdc_pata_cable_detect(struct ata_port *ap);
@@ -186,6 +190,7 @@ static struct ata_port_operations pdc_sata_ops = {
 	.scr_read		= pdc_sata_scr_read,
 	.scr_write		= pdc_sata_scr_write,
 	.port_start		= pdc_sata_port_start,
+	.hardreset		= pdc_sata_hardreset,
 };
 
 /* First-generation chips need a more restrictive ->check_atapi_dma op */
@@ -200,6 +205,7 @@ static struct ata_port_operations pdc_pata_ops = {
 	.freeze			= pdc_freeze,
 	.thaw			= pdc_thaw,
 	.port_start		= pdc_common_port_start,
+	.softreset		= pdc_pata_softreset,
 };
 
 static const struct ata_port_info pdc_port_info[] = {
@@ -693,6 +699,20 @@ static void pdc_sata_thaw(struct ata_port *ap)
 	readl(host_mmio + hotplug_offset); /* flush */
 }
 
+static int pdc_pata_softreset(struct ata_link *link, unsigned int *class,
+			      unsigned long deadline)
+{
+	pdc_reset_port(link->ap);
+	return ata_sff_softreset(link, class, deadline);
+}
+
+static int pdc_sata_hardreset(struct ata_link *link, unsigned int *class,
+			      unsigned long deadline)
+{
+	pdc_reset_port(link->ap);
+	return sata_sff_hardreset(link, class, deadline);
+}
+
 static void pdc_error_handler(struct ata_port *ap)
 {
 	if (!(ap->pflags & ATA_PFLAG_FROZEN))