libata: add deadline support to prereset and reset methods

Add @deadline to prereset and reset methods and make them honor it.
ata_wait_ready() which directly takes @deadline is implemented to be
used as the wait function.  This patch is in preparation for EH timing
improvements.

* ata_wait_ready() never does busy sleep.  It's only used from EH and
  no wait in EH is that urgent.  This function also prints 'be
  patient' message automatically after 5 secs of waiting if more than
  3 secs is remaining till deadline.

* ata_bus_post_reset() now fails with error code if any of its wait
  fails.  This is important because earlier reset tries will have
  shorter timeout than the spec requires.  If a device fails to
  respond before the short timeout, reset should be retried with
  longer timeout rather than silently ignoring the device.

  There are three behavior differences.

  1. Timeout is applied to both devices at once, not separately.  This
     is more consistent with what the spec says.

  2. When a device passes devchk but fails to become ready before
     deadline.  Previouly, post_reset would just succeed and let
     device classification remove the device.  New code fails the
     reset thus causing reset retry.  After a few times, EH will give
     up disabling the port.

  3. When slave device passes devchk but fails to become accessible
     (TF-wise) after reset.  Original code disables dev1 after 30s
     timeout and continues as if the device doesn't exist, while the
     patched code fails reset.  When this happens, new code fails
     reset on whole port rather than proceeding with only the primary
     device.

  If the failing device is suffering transient problems, new code
  retries reset which is a better behavior.  If the failing device is
  actually broken, the net effect is identical to it, but not to the
  other device sharing the channel.  In the previous code, reset would
  have succeeded after 30s thus detecting the working one.  In the new
  code, reset fails and whole port gets disabled.  IMO, it's a
  pathological case anyway (broken device sharing bus with working
  one) and doesn't really matter.

* ata_bus_softreset() is changed to return error code from
  ata_bus_post_reset().  It used to return 0 unconditionally.

* Spin up waiting is to be removed and not converted to honor
  deadline.

* To be on the safe side, deadline is set to 40s for the time being.

Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>

1 files changed, 15 insertions, 9 deletions

diff --git a/include/linux/libata.h b/include/linux/libata.h
index d8cfc72ea9c1..69fc1b8a9215 100644
--- a/include/linux/libata.h
+++ b/include/linux/libata.h
@@ -348,8 +348,9 @@ struct ata_queued_cmd;
 
 /* typedefs */
 typedef void (*ata_qc_cb_t) (struct ata_queued_cmd *qc);
-typedef int (*ata_prereset_fn_t)(struct ata_port *ap);
-typedef int (*ata_reset_fn_t)(struct ata_port *ap, unsigned int *classes);
+typedef int (*ata_prereset_fn_t)(struct ata_port *ap, unsigned long deadline);
+typedef int (*ata_reset_fn_t)(struct ata_port *ap, unsigned int *classes,
+			      unsigned long deadline);
 typedef void (*ata_postreset_fn_t)(struct ata_port *ap, unsigned int *classes);
 
 struct ata_ioports {
@@ -688,13 +689,17 @@ extern void __sata_phy_reset(struct ata_port *ap);
 extern void sata_phy_reset(struct ata_port *ap);
 extern void ata_bus_reset(struct ata_port *ap);
 extern int sata_set_spd(struct ata_port *ap);
-extern int sata_phy_debounce(struct ata_port *ap, const unsigned long *param);
-extern int sata_phy_resume(struct ata_port *ap, const unsigned long *param);
-extern int ata_std_prereset(struct ata_port *ap);
-extern int ata_std_softreset(struct ata_port *ap, unsigned int *classes);
-extern int sata_port_hardreset(struct ata_port *ap,
-			       const unsigned long *timing);
-extern int sata_std_hardreset(struct ata_port *ap, unsigned int *class);
+extern int sata_phy_debounce(struct ata_port *ap, const unsigned long *param,
+			     unsigned long deadline);
+extern int sata_phy_resume(struct ata_port *ap, const unsigned long *param,
+			   unsigned long deadline);
+extern int ata_std_prereset(struct ata_port *ap, unsigned long deadline);
+extern int ata_std_softreset(struct ata_port *ap, unsigned int *classes,
+			     unsigned long deadline);
+extern int sata_port_hardreset(struct ata_port *ap, const unsigned long *timing,
+			       unsigned long deadline);
+extern int sata_std_hardreset(struct ata_port *ap, unsigned int *class,
+			      unsigned long deadline);
 extern void ata_std_postreset(struct ata_port *ap, unsigned int *classes);
 extern void ata_port_disable(struct ata_port *);
 extern void ata_std_ports(struct ata_ioports *ioaddr);
@@ -750,6 +755,7 @@ extern void ata_host_resume(struct ata_host *host);
 extern int ata_ratelimit(void);
 extern int ata_busy_sleep(struct ata_port *ap,
 			  unsigned long timeout_pat, unsigned long timeout);
+extern int ata_wait_ready(struct ata_port *ap, unsigned long deadline);
 extern void ata_port_queue_task(struct ata_port *ap, work_func_t fn,
 				void *data, unsigned long delay);
 extern u32 ata_wait_register(void __iomem *reg, u32 mask, u32 val,