With hotplug, PHY always needs to be debounced before a reset as any
reset might find new devices. Extract PHY waiting code from
sata_phy_resume() and extend it to include SStatus debouncing. Note
that sata_phy_debounce() is superset of what used to be done inside
sata_phy_resume().
Two sets of debounce timings are defined and an argument is added to
sata_phy_resume() to select between the two.
---
drivers/scsi/libata-core.c | 103 ++++++++++++++++++++++++++++++++++++++------
include/linux/libata.h | 13 ++++++
2 files changed, 101 insertions(+), 15 deletions(-)
31e0810e495194fb383ea61ddd059f22449352b0
diff --git a/drivers/scsi/libata-core.c b/drivers/scsi/libata-core.c
index 1861373..636f044 100644
--- a/drivers/scsi/libata-core.c
+++ b/drivers/scsi/libata-core.c
@@ -2417,10 +2417,83 @@ err_out:
DPRINTK("EXIT\n");
}
-static int sata_phy_resume(struct ata_port *ap)
+/**
+ * sata_phy_debounce - debounce SATA phy status
+ * @ap: ATA port to debounce SATA phy status for
+ * @interval_msec: polling interval in millisecs
+ * @duration_msec: debounce duration in millisecs
+ * @timeout_msec: timeout in millisecs
+ *
+ * Make sure SStatus of @ap reaches stable state, determined by
+ * holding the same value where DET is not 1 for @duration_msec
+ * polled every @interval_msec, before @timeout_msec. Timeout
+ * constraints the beginning of the stable state. Because, after
+ * hot unplugging, DET gets stuck at 1 on some controllers, this
+ * functions waits until timeout then returns 0 if DET is stable
+ * at 1.
+ *
+ * LOCKING:
+ * Kernel thread context (may sleep)
+ *
+ * RETURNS:
+ * 0 on success, -errno on failure.
+ */
+int sata_phy_debounce(struct ata_port *ap, unsigned long interval_msec,
+ unsigned long duration_msec, unsigned long timeout_msec)
+{
+ unsigned long duration = duration_msec * HZ / 1000;
+ unsigned long timeout = jiffies + timeout_msec * HZ / 1000;
+ unsigned long last_jiffies;
+ u32 last, cur;
+ int rc;
+
+ if ((rc = ata_scr_read(ap, SCR_STATUS, &cur)))
+ return rc;
+ cur &= 0xf;
+
+ last = cur;
+ last_jiffies = jiffies;
+
+ while (1) {
+ msleep(interval_msec);
+ if ((rc = ata_scr_read(ap, SCR_STATUS, &cur)))
+ return rc;
+ cur &= 0xf;
+
+ /* DET stable? */
+ if (cur == last) {
+ if (cur == 1 && time_before(jiffies, timeout))
+ continue;
+ if (time_after(jiffies, last_jiffies + duration))
+ return 0;
+ continue;
+ }
+
+ /* unstable, start over */
+ last = cur;
+ last_jiffies = jiffies;
+
+ /* check timeout */
+ if (time_after(jiffies, timeout))
+ return -EBUSY;
+ }
+}
+
+/**
+ * sata_phy_resume - resume SATA phy
+ * @ap: ATA port to resume SATA phy for
+ *
+ * Resume SATA phy of @ap and debounce it.
+ *
+ * LOCKING:
+ * Kernel thread context (may sleep)
+ *
+ * RETURNS:
+ * 0 on success, -errno on failure.
+ */
+int sata_phy_resume(struct ata_port *ap, int quick)
{
- unsigned long timeout = jiffies + (HZ * 5);
- u32 scontrol, sstatus;
+ u32 scontrol;
int rc;
if ((rc = ata_scr_read(ap, SCR_CONTROL, &scontrol)))
@@ -2431,16 +2504,14 @@ static int sata_phy_resume(struct ata_po
if ((rc = ata_scr_write(ap, SCR_CONTROL, scontrol)))
return rc;
- /* Wait for phy to become ready, if necessary. */
- do {
- msleep(200);
- if ((rc = ata_scr_read(ap, SCR_STATUS, &sstatus)))
- return rc;
- if ((sstatus & 0xf) != 1)
- return 0;
- } while (time_before(jiffies, timeout));
-
- return -EBUSY;
+ if (quick)
+ return sata_phy_debounce(ap, ATA_DEBOUNCE_QUICK_INTERVAL,
+ ATA_DEBOUNCE_QUICK_DURATION,
+ ATA_DEBOUNCE_QUICK_TIMEOUT);
+ else
+ return sata_phy_debounce(ap, ATA_DEBOUNCE_INTERVAL,
+ ATA_DEBOUNCE_DURATION,
+ ATA_DEBOUNCE_TIMEOUT);
}
/**
@@ -2459,7 +2530,7 @@ static int sata_phy_resume(struct ata_po
void ata_std_probeinit(struct ata_port *ap)
{
/* resume link */
- sata_phy_resume(ap);
+ sata_phy_resume(ap, 1);
/* wait for device */
if (ata_port_online(ap))
@@ -2575,7 +2646,7 @@ int sata_std_hardreset(struct ata_port *
msleep(1);
/* bring phy back */
- sata_phy_resume(ap);
+ sata_phy_resume(ap, 0);
/* TODO: phy layer with polling, timeouts, etc. */
if (ata_port_offline(ap)) {
@@ -5722,6 +5793,8 @@ EXPORT_SYMBOL_GPL(ata_set_sata_spd);
EXPORT_SYMBOL_GPL(sata_phy_reset);
EXPORT_SYMBOL_GPL(__sata_phy_reset);
EXPORT_SYMBOL_GPL(ata_bus_reset);
+EXPORT_SYMBOL_GPL(sata_phy_debounce);
+EXPORT_SYMBOL_GPL(sata_phy_resume);
EXPORT_SYMBOL_GPL(ata_std_probeinit);
EXPORT_SYMBOL_GPL(ata_std_softreset);
EXPORT_SYMBOL_GPL(sata_std_hardreset);
diff --git a/include/linux/libata.h b/include/linux/libata.h
index f4a544e..5c843a8 100644
--- a/include/linux/libata.h
+++ b/include/linux/libata.h
@@ -255,6 +255,15 @@ enum {
ATA_PROBE_MAX_TRIES = 3,
ATA_EH_RESET_TRIES = 3,
ATA_EH_DEV_TRIES = 3,
+
+ /* timing constants in millisecs */
+ ATA_DEBOUNCE_QUICK_INTERVAL = 5,
+ ATA_DEBOUNCE_QUICK_DURATION = 100,
+ ATA_DEBOUNCE_QUICK_TIMEOUT = 5000,
+
+ ATA_DEBOUNCE_INTERVAL = 10,
+ ATA_DEBOUNCE_DURATION = 500,
+ ATA_DEBOUNCE_TIMEOUT = 10000,
};
enum hsm_task_states {
@@ -600,6 +609,10 @@ extern void __sata_phy_reset(struct ata_
extern void sata_phy_reset(struct ata_port *ap);
extern void ata_bus_reset(struct ata_port *ap);
extern int ata_set_sata_spd(struct ata_port *ap);
+extern int sata_phy_debounce(struct ata_port *ap, unsigned long interval_msec,
+ unsigned long duration_msec,
+ unsigned long timeout_msec);
+extern int sata_phy_resume(struct ata_port *ap, int quick);
extern int ata_drive_probe_reset(struct ata_port *ap,
ata_probeinit_fn_t probeinit,
ata_reset_fn_t softreset, ata_reset_fn_t hardreset,
--
1.2.4
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