libata: clear SError after link resume
SError used to be cleared in ->postreset. This has small hotplug race
condition. If a device is plugged in after reset is complete but
postreset hasn't run yet, its hotplug event gets lost when SError is
cleared. This patch makes sata_link_resume() clear SError. This
kills the race condition and makes a lot of sense as some PMP and host
PHYs don't work properly without SError cleared.
This change makes sata_pmp_std_{pre|post}_reset()'s unnecessary as
they become identical to ata_std counterparts. It also simplifies
sata_pmp_hardreset() and ahci_vt8251_hardreset().
Signed-off-by: Tejun Heo <htejun@gmail.com>
diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c
index c4fd4af..e00b620 100644
--- a/drivers/ata/libata-core.c
+++ b/drivers/ata/libata-core.c
@@ -90,9 +90,9 @@
const struct ata_port_operations sata_pmp_port_ops = {
.inherits = &sata_port_ops,
- .pmp_prereset = sata_pmp_std_prereset,
+ .pmp_prereset = ata_std_prereset,
.pmp_hardreset = sata_pmp_std_hardreset,
- .pmp_postreset = sata_pmp_std_postreset,
+ .pmp_postreset = ata_std_postreset,
.error_handler = sata_pmp_error_handler,
};
@@ -3493,7 +3493,7 @@
int sata_link_resume(struct ata_link *link, const unsigned long *params,
unsigned long deadline)
{
- u32 scontrol;
+ u32 scontrol, serror;
int rc;
if ((rc = sata_scr_read(link, SCR_CONTROL, &scontrol)))
@@ -3509,7 +3509,25 @@
*/
msleep(200);
- return sata_link_debounce(link, params, deadline);
+ if ((rc = sata_link_debounce(link, params, deadline)))
+ return rc;
+
+ /* Clear SError. PMP and some host PHYs require this to
+ * operate and clearing should be done before checking PHY
+ * online status to avoid race condition (hotplugging between
+ * link resume and status check).
+ */
+ if (!(rc = sata_scr_read(link, SCR_ERROR, &serror)))
+ rc = sata_scr_write(link, SCR_ERROR, serror);
+ if (rc == 0 || rc == -EINVAL) {
+ unsigned long flags;
+
+ spin_lock_irqsave(link->ap->lock, flags);
+ link->eh_info.serror = 0;
+ spin_unlock_irqrestore(link->ap->lock, flags);
+ rc = 0;
+ }
+ return rc;
}
/**
@@ -3701,18 +3719,11 @@
*/
void ata_std_postreset(struct ata_link *link, unsigned int *classes)
{
- u32 serror;
-
DPRINTK("ENTER\n");
/* print link status */
sata_print_link_status(link);
- /* clear SError */
- if (sata_scr_read(link, SCR_ERROR, &serror) == 0)
- sata_scr_write(link, SCR_ERROR, serror);
- link->eh_info.serror = 0;
-
DPRINTK("EXIT\n");
}
@@ -6296,9 +6307,7 @@
#endif /* CONFIG_PCI */
EXPORT_SYMBOL_GPL(sata_pmp_qc_defer_cmd_switch);
-EXPORT_SYMBOL_GPL(sata_pmp_std_prereset);
EXPORT_SYMBOL_GPL(sata_pmp_std_hardreset);
-EXPORT_SYMBOL_GPL(sata_pmp_std_postreset);
EXPORT_SYMBOL_GPL(sata_pmp_error_handler);
EXPORT_SYMBOL_GPL(__ata_ehi_push_desc);