Implement powersave timer. It is primarily for OS-driven HIPS
implementation but can be used for any other PS purpose LLD sees fit.
During normal operation, PS timer is automatically started with
timeout ap->ps_timeout on port idle and stopped when the port becomes
busy. The timer is also stopped while EH.
To minimize overhead and allow easy implementation of expected
operation model, ata_ps_timer_worker() is used as timer callback which
invokes LLD supplied ap->ps_timer_fn() if condition meets and also
helps implementing sequenced multi-step operation.
Signed-off-by: Tejun Heo <htejun@xxxxxxxxx>
---
drivers/scsi/libata-core.c | 90 +++++++++++++++++++++++++++++++++++++++++++-
drivers/scsi/libata-eh.c | 19 +++++++++
drivers/scsi/libata.h | 1
include/linux/libata.h | 8 ++++
4 files changed, 116 insertions(+), 2 deletions(-)
aa69e4ca8379e6db85e133f8e25bba00961201c7
diff --git a/drivers/scsi/libata-core.c b/drivers/scsi/libata-core.c
index b968b44..1658cd1 100644
--- a/drivers/scsi/libata-core.c
+++ b/drivers/scsi/libata-core.c
@@ -4425,13 +4425,15 @@ void ata_qc_complete(struct ata_queued_c
* taken care of.
*/
if (ap->ops->error_handler) {
+ int internal = ata_tag_internal(qc->tag);
+
WARN_ON(ap->pflags & ATA_PFLAG_FROZEN);
if (unlikely(qc->err_mask))
qc->flags |= ATA_QCFLAG_FAILED;
if (unlikely(qc->flags & ATA_QCFLAG_FAILED)) {
- if (!ata_tag_internal(qc->tag)) {
+ if (!internal) {
/* always fill result TF for failed qc */
ap->ops->tf_read(ap, &qc->result_tf);
ata_qc_schedule_eh(qc);
@@ -4444,6 +4446,13 @@ void ata_qc_complete(struct ata_queued_c
ap->ops->tf_read(ap, &qc->result_tf);
__ata_qc_complete(qc);
+
+ /* update PS timer */
+ if ((ap->pflags & ATA_PFLAG_PS_TIMER) &&
+ !ap->qc_active && !internal) {
+ ap->ps_seq = 0;
+ mod_timer(&ap->ps_timer, jiffies + ap->ps_timeout);
+ }
} else {
if (qc->flags & ATA_QCFLAG_EH_SCHEDULED)
return;
@@ -4551,6 +4560,9 @@ void ata_qc_issue(struct ata_queued_cmd
*/
WARN_ON(ap->ops->error_handler && ata_tag_valid(ap->active_tag));
+ if (ap->pflags & ATA_PFLAG_PS_TIMER)
+ del_timer(&ap->ps_timer);
+
if (qc->tf.protocol == ATA_PROT_NCQ) {
WARN_ON(ap->sactive & (1 << qc->tag));
ap->sactive |= 1 << qc->tag;
@@ -5207,6 +5219,77 @@ void ata_host_set_resume(struct ata_host
}
/**
+ * ata_kill_ps_timer - kill powersave timer
+ * @ap: ATA port of interest
+ *
+ * Kill powersave timer. On return from this function, powersave
+ * timer is guaranteed to be not pending && not running.
+ *
+ * LOCKING:
+ * None (must be called from EH context).
+ */
+void ata_kill_ps_timer(struct ata_port *ap)
+{
+ unsigned long flags;
+ int rc;
+
+ if (ap->pflags & ATA_PFLAG_PS_TIMER) {
+ do {
+ spin_lock_irqsave(ap->lock, flags);
+ rc = try_to_del_timer_sync(&ap->ps_timer);
+ ap->pflags &= ~ATA_PFLAG_PS_TIMER;
+ spin_unlock_irqrestore(ap->lock, flags);
+ cpu_relax();
+ } while (rc < 0);
+
+ ap->ps_timer_fn = NULL;
+ ap->ps_timeout = 0;
+ } else
+ BUG_ON(timer_pending(&ap->ps_timer));
+}
+
+/**
+ * ata_ps_timer_worker - powersave timer worker
+ * @arg: ATA port of interest
+ *
+ * This function is called when ap->ps_timer expires. If the
+ * condition is right, it calls ap->ps_timer_fn() with the
+ * current sequence number.
+ *
+ * libata automatically arms and cancels PS timer on port idle
+ * and command issue respectively. libata also initializes
+ * sequence number to zero when it arms PS timer because of port
+ * idle.
+ *
+ * ap->ps_timer_fn() can request requeue of PS timer by returning
+ * non-zero value which will be used as timeout. Each requeue
+ * increments PS sequence number by one.
+ *
+ * LOCKING:
+ * None.
+ */
+static void ata_ps_timer_worker(unsigned long arg)
+{
+ struct ata_port *ap = (void *)arg;
+ unsigned long flags;
+
+ spin_lock_irqsave(ap->lock, flags);
+
+ if (!ap->qc_active && !timer_pending(&ap->ps_timer)) {
+ unsigned long next_timeout;
+
+ next_timeout = ap->ps_timer_fn(ap, ap->ps_seq);
+ if (next_timeout) {
+ ap->ps_seq++;
+ ap->ps_timer.expires = jiffies + next_timeout;
+ add_timer(&ap->ps_timer);
+ }
+ }
+
+ spin_unlock_irqrestore(ap->lock, flags);
+}
+
+/**
* ata_port_start - Set port up for dma.
* @ap: Port to initialize
*
@@ -5439,6 +5522,7 @@ #endif
INIT_WORK(&ap->scsi_rescan_task, ata_scsi_dev_rescan, ap);
INIT_LIST_HEAD(&ap->eh_done_q);
init_waitqueue_head(&ap->eh_wait_q);
+ setup_timer(&ap->ps_timer, ata_ps_timer_worker, (unsigned long)ap);
/* set cable type */
ap->cbl = ATA_CBL_NONE;
@@ -5749,7 +5833,9 @@ void ata_port_detach(struct ata_port *ap
cancel_delayed_work(&ap->hotplug_task);
flush_workqueue(ata_aux_wq);
- /* turn it off */
+ /* kill PS timer and power off */
+ ata_kill_ps_timer(ap);
+
if (ap->ops->set_powersave)
ap->ops->set_powersave(ap, ATA_PS_STATIC);
diff --git a/drivers/scsi/libata-eh.c b/drivers/scsi/libata-eh.c
index d5126b7..b19eaae 100644
--- a/drivers/scsi/libata-eh.c
+++ b/drivers/scsi/libata-eh.c
@@ -261,6 +261,9 @@ void ata_scsi_error(struct Scsi_Host *ho
} else
spin_unlock_wait(ap->lock);
+ /* kill powersave timer before beginning EH */
+ ata_kill_ps_timer(ap);
+
repeat:
/* invoke error handler */
if (ap->ops->error_handler) {
@@ -340,6 +343,14 @@ void ata_scsi_error(struct Scsi_Host *ho
ap->pflags &= ~(ATA_PFLAG_SCSI_HOTPLUG | ATA_PFLAG_RECOVERED);
+ /* start PS timer if requested */
+ if (ap->pflags & ATA_PFLAG_PS_TIMER) {
+ BUG_ON(!ap->ps_timer_fn || !ap->ps_timeout);
+ ap->ps_seq = 0;
+ ap->ps_timer.expires = jiffies + ap->ps_timeout;
+ add_timer(&ap->ps_timer);
+ }
+
/* tell wait_eh that we're done */
ap->pflags &= ~ATA_PFLAG_EH_IN_PROGRESS;
wake_up_all(&ap->eh_wait_q);
@@ -1876,11 +1887,13 @@ static int ata_eh_set_powersave(struct a
void (*set_ps)(struct ata_port *, int) = ap->ops->set_powersave;
int ps_state, ps_static, ps_dynamic;
int dev_dips, dev_hips, i;
+ unsigned long flags;
/* power up for recovery */
if (r_failed_dev == NULL) {
if (ap->ps_state && set_ps)
set_ps(ap, ATA_PS_NONE);
+ WARN_ON(ap->flags & ATA_PFLAG_PS_TIMER);
return 0;
}
@@ -1929,9 +1942,15 @@ static int ata_eh_set_powersave(struct a
err_mask = ata_dev_set_dips(dev, is_dips);
if (err_mask) {
+ spin_lock_irqsave(ap->lock, flags);
+ ap->pflags &= ~ATA_PFLAG_PS_TIMER;
+ spin_unlock_irqrestore(ap->lock, flags);
+
if (ps_state && set_ps)
set_ps(ap, ATA_PS_NONE);
+
*r_failed_dev = dev;
+
return -EIO;
}
}
diff --git a/drivers/scsi/libata.h b/drivers/scsi/libata.h
index ce44e06..9e44f56 100644
--- a/drivers/scsi/libata.h
+++ b/drivers/scsi/libata.h
@@ -74,6 +74,7 @@ extern void ata_dev_select(struct ata_po
unsigned int wait, unsigned int can_sleep);
extern void swap_buf_le16(u16 *buf, unsigned int buf_words);
extern int ata_flush_cache(struct ata_device *dev);
+extern void ata_kill_ps_timer(struct ata_port *ap);
extern void ata_dev_init(struct ata_device *dev);
extern int ata_task_ioctl(struct scsi_device *scsidev, void __user *arg);
extern int ata_cmd_ioctl(struct scsi_device *scsidev, void __user *arg);
diff --git a/include/linux/libata.h b/include/linux/libata.h
index b3f56c5..0881814 100644
--- a/include/linux/libata.h
+++ b/include/linux/libata.h
@@ -185,6 +185,7 @@ enum {
ATA_PFLAG_FLUSH_PORT_TASK = (1 << 16), /* flush port task */
ATA_PFLAG_SUSPENDED = (1 << 17), /* port is suspended (power) */
ATA_PFLAG_PM_PENDING = (1 << 18), /* PM operation pending */
+ ATA_PFLAG_PS_TIMER = (1 << 19), /* PS timer active */
/* struct ata_queued_cmd flags */
ATA_QCFLAG_ACTIVE = (1 << 0), /* cmd not yet ack'd to scsi lyer */
@@ -335,6 +336,7 @@ typedef void (*ata_qc_cb_t) (struct ata_
typedef int (*ata_prereset_fn_t)(struct ata_port *ap);
typedef int (*ata_reset_fn_t)(struct ata_port *ap, unsigned int *classes);
typedef void (*ata_postreset_fn_t)(struct ata_port *ap, unsigned int *classes);
+typedef unsigned long (*ata_ps_timer_fn_t)(struct ata_port *ap, int seq);
struct ata_ioports {
unsigned long cmd_addr;
@@ -568,6 +570,12 @@ struct ata_port {
/* powersave (dynamic link power management) */
int target_ps_state;
int ps_state;
+ /* powersave timer, protected by ap->lock */
+ ata_ps_timer_fn_t ps_timer_fn; /* initialized by LLD */
+ unsigned long ps_timeout; /* ditto */
+
+ int ps_seq; /* managed by libata */
+ struct timer_list ps_timer; /* ditto */
/* power management (host suspend and resume) */
pm_message_t pm_mesg;
--
1.3.2
-
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