ata: move sata_link_{debounce,resume}() to libata-sata.c

[linux-2.6-microblaze.git] / drivers / ata / libata-sata.c

diff --git a/drivers/ata/libata-sata.c b/drivers/ata/libata-sata.c
index d66afdc..34852fc 100644 (file)
--- a/drivers/ata/libata-sata.c
+++ b/drivers/ata/libata-sata.c
@@ -196,6 +196,144 @@ void ata_tf_from_fis(const u8 *fis, struct ata_taskfile *tf)
 }
 EXPORT_SYMBOL_GPL(ata_tf_from_fis);
 
+/**
+ *     sata_link_debounce - debounce SATA phy status
+ *     @link: ATA link to debounce SATA phy status for
+ *     @params: timing parameters { interval, duration, timeout } in msec
+ *     @deadline: deadline jiffies for the operation
+ *
+ *     Make sure SStatus of @link reaches stable state, determined by
+ *     holding the same value where DET is not 1 for @duration polled
+ *     every @interval, before @timeout.  Timeout constraints the
+ *     beginning of the stable state.  Because DET gets stuck at 1 on
+ *     some controllers after hot unplugging, this functions waits
+ *     until timeout then returns 0 if DET is stable at 1.
+ *
+ *     @timeout is further limited by @deadline.  The sooner of the
+ *     two is used.
+ *
+ *     LOCKING:
+ *     Kernel thread context (may sleep)
+ *
+ *     RETURNS:
+ *     0 on success, -errno on failure.
+ */
+int sata_link_debounce(struct ata_link *link, const unsigned long *params,
+                      unsigned long deadline)
+{
+       unsigned long interval = params[0];
+       unsigned long duration = params[1];
+       unsigned long last_jiffies, t;
+       u32 last, cur;
+       int rc;
+
+       t = ata_deadline(jiffies, params[2]);
+       if (time_before(t, deadline))
+               deadline = t;
+
+       if ((rc = sata_scr_read(link, SCR_STATUS, &cur)))
+               return rc;
+       cur &= 0xf;
+
+       last = cur;
+       last_jiffies = jiffies;
+
+       while (1) {
+               ata_msleep(link->ap, interval);
+               if ((rc = sata_scr_read(link, SCR_STATUS, &cur)))
+                       return rc;
+               cur &= 0xf;
+
+               /* DET stable? */
+               if (cur == last) {
+                       if (cur == 1 && time_before(jiffies, deadline))
+                               continue;
+                       if (time_after(jiffies,
+                                      ata_deadline(last_jiffies, duration)))
+                               return 0;
+                       continue;
+               }
+
+               /* unstable, start over */
+               last = cur;
+               last_jiffies = jiffies;
+
+               /* Check deadline.  If debouncing failed, return
+                * -EPIPE to tell upper layer to lower link speed.
+                */
+               if (time_after(jiffies, deadline))
+                       return -EPIPE;
+       }
+}
+EXPORT_SYMBOL_GPL(sata_link_debounce);
+
+/**
+ *     sata_link_resume - resume SATA link
+ *     @link: ATA link to resume SATA
+ *     @params: timing parameters { interval, duration, timeout } in msec
+ *     @deadline: deadline jiffies for the operation
+ *
+ *     Resume SATA phy @link and debounce it.
+ *
+ *     LOCKING:
+ *     Kernel thread context (may sleep)
+ *
+ *     RETURNS:
+ *     0 on success, -errno on failure.
+ */
+int sata_link_resume(struct ata_link *link, const unsigned long *params,
+                    unsigned long deadline)
+{
+       int tries = ATA_LINK_RESUME_TRIES;
+       u32 scontrol, serror;
+       int rc;
+
+       if ((rc = sata_scr_read(link, SCR_CONTROL, &scontrol)))
+               return rc;
+
+       /*
+        * Writes to SControl sometimes get ignored under certain
+        * controllers (ata_piix SIDPR).  Make sure DET actually is
+        * cleared.
+        */
+       do {
+               scontrol = (scontrol & 0x0f0) | 0x300;
+               if ((rc = sata_scr_write(link, SCR_CONTROL, scontrol)))
+                       return rc;
+               /*
+                * Some PHYs react badly if SStatus is pounded
+                * immediately after resuming.  Delay 200ms before
+                * debouncing.
+                */
+               if (!(link->flags & ATA_LFLAG_NO_DB_DELAY))
+                       ata_msleep(link->ap, 200);
+
+               /* is SControl restored correctly? */
+               if ((rc = sata_scr_read(link, SCR_CONTROL, &scontrol)))
+                       return rc;
+       } while ((scontrol & 0xf0f) != 0x300 && --tries);
+
+       if ((scontrol & 0xf0f) != 0x300) {
+               ata_link_warn(link, "failed to resume link (SControl %X)\n",
+                            scontrol);
+               return 0;
+       }
+
+       if (tries < ATA_LINK_RESUME_TRIES)
+               ata_link_warn(link, "link resume succeeded after %d retries\n",
+                             ATA_LINK_RESUME_TRIES - tries);
+
+       if ((rc = sata_link_debounce(link, params, deadline)))
+               return rc;
+
+       /* clear SError, some PHYs require this even for SRST to work */
+       if (!(rc = sata_scr_read(link, SCR_ERROR, &serror)))
+               rc = sata_scr_write(link, SCR_ERROR, serror);
+
+       return rc != -EINVAL ? rc : 0;
+}
+EXPORT_SYMBOL_GPL(sata_link_resume);
+
 /**
  *     sata_link_scr_lpm - manipulate SControl IPM and SPM fields
  *     @link: ATA link to manipulate SControl for