sata_mv delayed eh handling

Introduce a new "delayed error handling" mechanism in sata_mv,
to enable us to eventually deal with multiple simultaneous NCQ
failures on a single host link when a PM is present.

This involves a port flag (MV_PP_FLAG_DELAYED_EH) to prevent new
commands being queued, and a pmp bitmap to indicate which pmp links
had NCQ errors.

The new mv_pmp_error_handler() uses those values to invoke
ata_eh_analyze_ncq_error() on each failed link, prior to freezing
the port and passing control to sata_pmp_error_handler().

This is based upon a strategy suggested by Tejun.

For now, we just implement the delayed mechanism.
The next patch in this series will add the multiple-NCQ EH code
to take advantage of it.

Signed-off-by: Mark Lord <mlord@pobox.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>

1 files changed, 37 insertions, 1 deletions

diff --git a/drivers/ata/sata_mv.c b/drivers/ata/sata_mv.c
index 803578ef22f8..1991eb22e388 100644
--- a/drivers/ata/sata_mv.c
+++ b/drivers/ata/sata_mv.c
@@ -367,6 +367,7 @@ enum {
         MV_PP_FLAG_EDMA_EN      = (1 << 0),     /* is EDMA engine enabled? */
         MV_PP_FLAG_NCQ_EN       = (1 << 1),     /* is EDMA set up for NCQ? */
         MV_PP_FLAG_FBS_EN       = (1 << 2),     /* is EDMA set up for FBS? */
+        MV_PP_FLAG_DELAYED_EH   = (1 << 3),     /* delayed dev err handling */
 };
 
 #define IS_GEN_I(hpriv) ((hpriv)->hp_flags & MV_HP_GEN_I)
@@ -447,6 +448,7 @@ struct mv_port_priv {
         unsigned int            resp_idx;
 
         u32                     pp_flags;
+        unsigned int            delayed_eh_pmp_map;
 };
 
 struct mv_port_signal {
@@ -542,6 +544,7 @@ static int mv_pmp_hardreset(struct ata_link *link, unsigned int *class,
                                 unsigned long deadline);
 static int  mv_softreset(struct ata_link *link, unsigned int *class,
                                 unsigned long deadline);
+static void mv_pmp_error_handler(struct ata_port *ap);
 
 /* .sg_tablesize is (MV_MAX_SG_CT / 2) in the structures below
  * because we have to allow room for worst case splitting of
@@ -589,7 +592,7 @@ static struct ata_port_operations mv6_ops = {
         .pmp_hardreset          = mv_pmp_hardreset,
         .pmp_softreset          = mv_softreset,
         .softreset              = mv_softreset,
-        .error_handler          = sata_pmp_error_handler,
+        .error_handler          = mv_pmp_error_handler,
 };
 
 static struct ata_port_operations mv_iie_ops = {
@@ -1098,6 +1101,12 @@ static int mv_qc_defer(struct ata_queued_cmd *qc)
         struct mv_port_priv *pp = ap->private_data;
 
         /*
+         * Don't allow new commands if we're in a delayed EH state
+         * for NCQ and/or FIS-based switching.
+         */
+        if (pp->pp_flags & MV_PP_FLAG_DELAYED_EH)
+                return ATA_DEFER_PORT;
+        /*
          * If the port is completely idle, then allow the new qc.
          */
         if (ap->nr_active_links == 0)
@@ -1591,6 +1600,33 @@ static struct ata_queued_cmd *mv_get_active_qc(struct ata_port *ap)
         return qc;
 }
 
+static void mv_pmp_error_handler(struct ata_port *ap)
+{
+        unsigned int pmp, pmp_map;
+        struct mv_port_priv *pp = ap->private_data;
+
+        if (pp->pp_flags & MV_PP_FLAG_DELAYED_EH) {
+                /*
+                 * Perform NCQ error analysis on failed PMPs
+                 * before we freeze the port entirely.
+                 *
+                 * The failed PMPs are marked earlier by mv_pmp_eh_prep().
+                 */
+                pmp_map = pp->delayed_eh_pmp_map;
+                pp->pp_flags &= ~MV_PP_FLAG_DELAYED_EH;
+                for (pmp = 0; pmp_map != 0; pmp++) {
+                        unsigned int this_pmp = (1 << pmp);
+                        if (pmp_map & this_pmp) {
+                                struct ata_link *link = &ap->pmp_link[pmp];
+                                pmp_map &= ~this_pmp;
+                                ata_eh_analyze_ncq_error(link);
+                        }
+                }
+                ata_port_freeze(ap);
+        }
+        sata_pmp_error_handler(ap);
+}
+
 static void mv_unexpected_intr(struct ata_port *ap, int edma_was_enabled)
 {
         struct ata_eh_info *ehi = &ap->link.eh_info;