libata: track SLEEP state and issue SRST to wake it up

ATA devices in SLEEP mode don't respond to any commands.  SRST is
necessary to wake it up.  Till now, when a command is issued to a
device in SLEEP mode, the command times out, which makes EH reset the
device and retry the command after that, causing a long delay.

This patch makes libata track SLEEP state and issue SRST automatically
if a command is about to be issued to a device in SLEEP.

Signed-off-by: Tejun Heo <htejun@gmail.com>
Cc: Bruce Allen <ballen@gravity.phys.uwm.edu>
Cc: Andrew Paprocki <andrew@ishiboo.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>

4 files changed, 17 insertions, 1 deletions

diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c
index 5aedd1af06e6..50ae20101d10 100644
--- a/drivers/ata/libata-core.c
+++ b/drivers/ata/libata-core.c
@@ -5630,6 +5630,10 @@ void ata_qc_complete(struct ata_queued_cmd *qc)
                         ehi->dev_action[dev->devno] |= ATA_EH_REVALIDATE;
                         ata_port_schedule_eh(ap);
                         break;
+
+                case ATA_CMD_SLEEP:
+                        dev->flags |= ATA_DFLAG_SLEEPING;
+                        break;
                 }
 
                 __ata_qc_complete(qc);
@@ -5769,6 +5773,14 @@ void ata_qc_issue(struct ata_queued_cmd *qc)
                 qc->flags &= ~ATA_QCFLAG_DMAMAP;
         }
 
+        /* if device is sleeping, schedule softreset and abort the link */
+        if (unlikely(qc->dev->flags & ATA_DFLAG_SLEEPING)) {
+                link->eh_info.action |= ATA_EH_SOFTRESET;
+                ata_ehi_push_desc(&link->eh_info, "waking up from sleep");
+                ata_link_abort(link);
+                return;
+        }
+
         ap->ops->qc_prep(qc);
 
         qc->err_mask |= ap->ops->qc_issue(qc);
diff --git a/drivers/ata/libata-eh.c b/drivers/ata/libata-eh.c
index 8cb35bb87605..496edaff119a 100644
--- a/drivers/ata/libata-eh.c
+++ b/drivers/ata/libata-eh.c
@@ -2208,9 +2208,11 @@ int ata_eh_reset(struct ata_link *link, int classify,
                 ata_link_for_each_dev(dev, link) {
                         /* After the reset, the device state is PIO 0
                          * and the controller state is undefined.
-                         * Record the mode.
+                         * Reset also wakes up drives from sleeping
+                         * mode.
                          */
                         dev->pio_mode = XFER_PIO_0;
+                        dev->flags &= ~ATA_DFLAG_SLEEPING;
 
                         if (ata_link_offline(link))
                                 continue;
diff --git a/include/linux/ata.h b/include/linux/ata.h
index 8263a7b74d34..e21c002c3a4a 100644
--- a/include/linux/ata.h
+++ b/include/linux/ata.h
@@ -180,6 +180,7 @@ enum {
         ATA_CMD_VERIFY_EXT      = 0x42,
         ATA_CMD_STANDBYNOW1     = 0xE0,
         ATA_CMD_IDLEIMMEDIATE   = 0xE1,
+        ATA_CMD_SLEEP           = 0xE6,
         ATA_CMD_INIT_DEV_PARAMS = 0x91,
         ATA_CMD_READ_NATIVE_MAX = 0xF8,
         ATA_CMD_READ_NATIVE_MAX_EXT = 0x27,
diff --git a/include/linux/libata.h b/include/linux/libata.h
index 6fd24e03622e..2f0fc636b4b6 100644
--- a/include/linux/libata.h
+++ b/include/linux/libata.h
@@ -138,6 +138,7 @@ enum {
         ATA_DFLAG_PIO           = (1 << 12), /* device limited to PIO mode */
         ATA_DFLAG_NCQ_OFF       = (1 << 13), /* device limited to non-NCQ mode */
         ATA_DFLAG_SPUNDOWN      = (1 << 14), /* XXX: for spindown_compat */
+        ATA_DFLAG_SLEEPING      = (1 << 15), /* device is sleeping */
         ATA_DFLAG_INIT_MASK     = (1 << 16) - 1,
 
         ATA_DFLAG_DETACH        = (1 << 16),