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Subject[PATCH 2.6.25-rc6] sata_promise: fix hardreset hotplug quirk
There is an undocumented hardware quirk in Promise's SATA controllers,
where a SATA COMRESET causes the controller to signal hotplug events.
These unexpected interrupts confuse libata's error handler and cause
a sequence of failed reset attempts until EH finally gives up.

This has not been a common problem so far, but the pending libata
hardreset-by-default changes makes it a critical issue.

The solution is to disable hotplug events before a reset, and to
reenable them afterwards. (Promise's driver uses the same solution.)

This patch adds SATA-specific versions of ->freeze() and ->thaw() that
also disable and enable hotplug events. PATA ports continue to use the
old versions of ->freeze() and ->thaw().

Although SATA hotplug status and control is per-port, it resides in
a single register shared by all ports. Therefore accesses to it must
be serialised: the controller's host->lock is used for that. The
interrupt handler is also adjusted so its hotplug register accesses
are inside the region protected by host->lock.

Tested on various chips (SATA300TX4, SATA300TX2plus, SATAII150TX4,
FastTrack TX4000) with various combinations of SATA and PATA disks,
with and without the pending hardreset-by-default changes.

Signed-off-by: Mikael Pettersson <mikpe@it.uu.se>
---
drivers/ata/sata_promise.c | 115 ++++++++++++++++++++++++++++++++++++---------
1 file changed, 94 insertions(+), 21 deletions(-)
diff -rupN linux-2.6.25-rc6/drivers/ata/sata_promise.c linux-2.6.25-rc6.sata_promise-fix-hardreset-hotplug-quirk/drivers/ata/sata_promise.c
--- linux-2.6.25-rc6/drivers/ata/sata_promise.c 2008-03-22 12:53:32.000000000 +0100
+++ linux-2.6.25-rc6.sata_promise-fix-hardreset-hotplug-quirk/drivers/ata/sata_promise.c 2008-03-22 12:59:36.000000000 +0100
@@ -46,7 +46,7 @@
#include "sata_promise.h"

#define DRV_NAME "sata_promise"
-#define DRV_VERSION "2.11"
+#define DRV_VERSION "2.12"

enum {
PDC_MAX_PORTS = 4,
@@ -145,7 +145,9 @@ static int pdc_old_sata_check_atapi_dma(
static void pdc_irq_clear(struct ata_port *ap);
static unsigned int pdc_qc_issue_prot(struct ata_queued_cmd *qc);
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 void pdc_pata_error_handler(struct ata_port *ap);
static void pdc_sata_error_handler(struct ata_port *ap);
static void pdc_post_internal_cmd(struct ata_queued_cmd *qc);
@@ -180,8 +182,8 @@ static const struct ata_port_operations

.qc_prep = pdc_qc_prep,
.qc_issue = pdc_qc_issue_prot,
- .freeze = pdc_freeze,
- .thaw = pdc_thaw,
+ .freeze = pdc_sata_freeze,
+ .thaw = pdc_sata_thaw,
.error_handler = pdc_sata_error_handler,
.post_internal_cmd = pdc_post_internal_cmd,
.cable_detect = pdc_sata_cable_detect,
@@ -205,8 +207,8 @@ static const struct ata_port_operations

.qc_prep = pdc_qc_prep,
.qc_issue = pdc_qc_issue_prot,
- .freeze = pdc_freeze,
- .thaw = pdc_thaw,
+ .freeze = pdc_sata_freeze,
+ .thaw = pdc_sata_thaw,
.error_handler = pdc_sata_error_handler,
.post_internal_cmd = pdc_post_internal_cmd,
.cable_detect = pdc_sata_cable_detect,
@@ -631,6 +633,78 @@ static void pdc_qc_prep(struct ata_queue
}
}

+static int pdc_is_sataii_tx4(unsigned long flags)
+{
+ const unsigned long mask = PDC_FLAG_GEN_II | PDC_FLAG_4_PORTS;
+ return (flags & mask) == mask;
+}
+
+static unsigned int pdc_port_no_to_ata_no(unsigned int port_no,
+ int is_sataii_tx4)
+{
+ static const unsigned char sataii_tx4_port_remap[4] = { 3, 1, 0, 2};
+ return is_sataii_tx4 ? sataii_tx4_port_remap[port_no] : port_no;
+}
+
+static unsigned int pdc_sata_nr_ports(const struct ata_port *ap)
+{
+ return (ap->flags & PDC_FLAG_4_PORTS) ? 4 : 2;
+}
+
+static unsigned int pdc_sata_ata_port_to_ata_no(const struct ata_port *ap)
+{
+ const struct ata_host *host = ap->host;
+ unsigned int nr_ports = pdc_sata_nr_ports(ap);
+ unsigned int i;
+
+ for(i = 0; i < nr_ports && host->ports[i] != ap; ++i)
+ ;
+ BUG_ON(i >= nr_ports);
+ return pdc_port_no_to_ata_no(i, pdc_is_sataii_tx4(ap->flags));
+}
+
+static unsigned int pdc_sata_hotplug_offset(const struct ata_port *ap)
+{
+ return (ap->flags & PDC_FLAG_GEN_II) ? PDC2_SATA_PLUG_CSR : PDC_SATA_PLUG_CSR;
+}
+
+static void pdc_sata_disable_hotplug(const struct ata_port *ap)
+{
+ struct ata_host *host = ap->host;
+ void __iomem *host_mmio = host->iomap[PDC_MMIO_BAR];
+ unsigned int hotplug_offset = pdc_sata_hotplug_offset(ap);
+ unsigned int ata_no = pdc_sata_ata_port_to_ata_no(ap);
+ u32 hotplug_status;
+
+ spin_lock(&host->lock);
+
+ hotplug_status = readl(host_mmio + hotplug_offset);
+ hotplug_status |= 0x11 << (ata_no + 16);
+ writel(hotplug_status, host_mmio + hotplug_offset);
+ readl(host_mmio + hotplug_offset); /* flush */
+
+ spin_unlock(&host->lock);
+}
+
+static void pdc_sata_enable_hotplug(const struct ata_port *ap)
+{
+ struct ata_host *host = ap->host;
+ void __iomem *host_mmio = host->iomap[PDC_MMIO_BAR];
+ unsigned int hotplug_offset = pdc_sata_hotplug_offset(ap);
+ unsigned int ata_no = pdc_sata_ata_port_to_ata_no(ap);
+ u32 hotplug_status;
+
+ spin_lock(&host->lock);
+
+ hotplug_status = readl(host_mmio + hotplug_offset);
+ hotplug_status |= 0x11 << ata_no;
+ hotplug_status &= ~(0x11 << (ata_no + 16));
+ writel(hotplug_status, host_mmio + hotplug_offset);
+ readl(host_mmio + hotplug_offset); /* flush */
+
+ spin_unlock(&host->lock);
+}
+
static void pdc_freeze(struct ata_port *ap)
{
void __iomem *mmio = ap->ioaddr.cmd_addr;
@@ -643,6 +717,12 @@ static void pdc_freeze(struct ata_port *
readl(mmio + PDC_CTLSTAT); /* flush */
}

+static void pdc_sata_freeze(struct ata_port *ap)
+{
+ pdc_sata_disable_hotplug(ap);
+ pdc_freeze(ap);
+}
+
static void pdc_thaw(struct ata_port *ap)
{
void __iomem *mmio = ap->ioaddr.cmd_addr;
@@ -658,6 +738,12 @@ static void pdc_thaw(struct ata_port *ap
readl(mmio + PDC_CTLSTAT); /* flush */
}

+static void pdc_sata_thaw(struct ata_port *ap)
+{
+ pdc_thaw(ap);
+ pdc_sata_enable_hotplug(ap);
+}
+
static void pdc_common_error_handler(struct ata_port *ap, ata_reset_fn_t hardreset)
{
if (!(ap->pflags & ATA_PFLAG_FROZEN))
@@ -765,19 +851,6 @@ static void pdc_irq_clear(struct ata_por
readl(mmio + PDC_INT_SEQMASK);
}

-static int pdc_is_sataii_tx4(unsigned long flags)
-{
- const unsigned long mask = PDC_FLAG_GEN_II | PDC_FLAG_4_PORTS;
- return (flags & mask) == mask;
-}
-
-static unsigned int pdc_port_no_to_ata_no(unsigned int port_no,
- int is_sataii_tx4)
-{
- static const unsigned char sataii_tx4_port_remap[4] = { 3, 1, 0, 2};
- return is_sataii_tx4 ? sataii_tx4_port_remap[port_no] : port_no;
-}
-
static irqreturn_t pdc_interrupt(int irq, void *dev_instance)
{
struct ata_host *host = dev_instance;
@@ -799,6 +872,8 @@ static irqreturn_t pdc_interrupt(int irq

mmio_base = host->iomap[PDC_MMIO_BAR];

+ spin_lock(&host->lock);
+
/* read and clear hotplug flags for all ports */
if (host->ports[0]->flags & PDC_FLAG_GEN_II)
hotplug_offset = PDC2_SATA_PLUG_CSR;
@@ -814,11 +889,9 @@ static irqreturn_t pdc_interrupt(int irq

if (mask == 0xffffffff && hotplug_status == 0) {
VPRINTK("QUICK EXIT 2\n");
- return IRQ_NONE;
+ goto done_irq;
}

- spin_lock(&host->lock);
-
mask &= 0xffff; /* only 16 tags possible */
if (mask == 0 && hotplug_status == 0) {
VPRINTK("QUICK EXIT 3\n");

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