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>

diff --git a/drivers/ata/sata_mv.c b/drivers/ata/sata_mv.c
index 803578e..1991eb2 100644 (file)
--- 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;