[libata] sata_mv: Micro-optimization and cleanups

* Micro-optimization in the EDMA interrupt handling code
* s/EDMA_ERR_CRBQ_PAR/EDMA_ERR_CRQB_PAR/
* Document EDMA Error Interrupt Cause register bits

Signed-off-by: Jeff Garzik <jeff@garzik.org>

1 files changed, 31 insertions, 34 deletions

diff --git a/drivers/ata/sata_mv.c b/drivers/ata/sata_mv.c
index fb8a749423ca..0ccd990c8dac 100644
--- a/drivers/ata/sata_mv.c
+++ b/drivers/ata/sata_mv.c
@@ -227,26 +227,26 @@ enum {
 
         EDMA_ERR_IRQ_CAUSE_OFS  = 0x8,
         EDMA_ERR_IRQ_MASK_OFS   = 0xc,
-        EDMA_ERR_D_PAR          = (1 << 0),
-        EDMA_ERR_PRD_PAR        = (1 << 1),
-        EDMA_ERR_DEV            = (1 << 2),
-        EDMA_ERR_DEV_DCON       = (1 << 3),
-        EDMA_ERR_DEV_CON        = (1 << 4),
-        EDMA_ERR_SERR           = (1 << 5),
+        EDMA_ERR_D_PAR          = (1 << 0),     /* UDMA data parity err */
+        EDMA_ERR_PRD_PAR        = (1 << 1),     /* UDMA PRD parity err */
+        EDMA_ERR_DEV            = (1 << 2),     /* device error */
+        EDMA_ERR_DEV_DCON       = (1 << 3),     /* device disconnect */
+        EDMA_ERR_DEV_CON        = (1 << 4),     /* device connected */
+        EDMA_ERR_SERR           = (1 << 5),     /* SError bits [WBDST] raised */
         EDMA_ERR_SELF_DIS       = (1 << 7),     /* Gen II/IIE self-disable */
         EDMA_ERR_SELF_DIS_5     = (1 << 8),     /* Gen I self-disable */
-        EDMA_ERR_BIST_ASYNC     = (1 << 8),
+        EDMA_ERR_BIST_ASYNC     = (1 << 8),     /* BIST FIS or Async Notify */
         EDMA_ERR_TRANS_IRQ_7    = (1 << 8),     /* Gen IIE transprt layer irq */
-        EDMA_ERR_CRBQ_PAR       = (1 << 9),
-        EDMA_ERR_CRPB_PAR       = (1 << 10),
-        EDMA_ERR_INTRL_PAR      = (1 << 11),
-        EDMA_ERR_IORDY          = (1 << 12),
-        EDMA_ERR_LNK_CTRL_RX    = (0xf << 13),
+        EDMA_ERR_CRQB_PAR       = (1 << 9),     /* CRQB parity error */
+        EDMA_ERR_CRPB_PAR       = (1 << 10),    /* CRPB parity error */
+        EDMA_ERR_INTRL_PAR      = (1 << 11),    /* internal parity error */
+        EDMA_ERR_IORDY          = (1 << 12),    /* IORdy timeout */
+        EDMA_ERR_LNK_CTRL_RX    = (0xf << 13),  /* link ctrl rx error */
         EDMA_ERR_LNK_CTRL_RX_2  = (1 << 15),
-        EDMA_ERR_LNK_DATA_RX    = (0xf << 17),
-        EDMA_ERR_LNK_CTRL_TX    = (0x1f << 21),
-        EDMA_ERR_LNK_DATA_TX    = (0x1f << 26),
-        EDMA_ERR_TRANS_PROTO    = (1 << 31),
+        EDMA_ERR_LNK_DATA_RX    = (0xf << 17),  /* link data rx error */
+        EDMA_ERR_LNK_CTRL_TX    = (0x1f << 21), /* link ctrl tx error */
+        EDMA_ERR_LNK_DATA_TX    = (0x1f << 26), /* link data tx error */
+        EDMA_ERR_TRANS_PROTO    = (1 << 31),    /* transport protocol error */
         EDMA_ERR_OVERRUN_5      = (1 << 5),
         EDMA_ERR_UNDERRUN_5     = (1 << 6),
         EDMA_EH_FREEZE          = EDMA_ERR_D_PAR |
@@ -255,7 +255,7 @@ enum {
                                   EDMA_ERR_DEV_CON |
                                   EDMA_ERR_SERR |
                                   EDMA_ERR_SELF_DIS |
-                                  EDMA_ERR_CRBQ_PAR |
+                                  EDMA_ERR_CRQB_PAR |
                                   EDMA_ERR_CRPB_PAR |
                                   EDMA_ERR_INTRL_PAR |
                                   EDMA_ERR_IORDY |
@@ -270,7 +270,7 @@ enum {
                                   EDMA_ERR_OVERRUN_5 |
                                   EDMA_ERR_UNDERRUN_5 |
                                   EDMA_ERR_SELF_DIS_5 |
-                                  EDMA_ERR_CRBQ_PAR |
+                                  EDMA_ERR_CRQB_PAR |
                                   EDMA_ERR_CRPB_PAR |
                                   EDMA_ERR_INTRL_PAR |
                                   EDMA_ERR_IORDY,
@@ -1393,7 +1393,7 @@ static void mv_err_intr(struct ata_port *ap, struct ata_queued_cmd *qc)
         if (edma_err_cause & EDMA_ERR_DEV)
                 err_mask |= AC_ERR_DEV;
         if (edma_err_cause & (EDMA_ERR_D_PAR | EDMA_ERR_PRD_PAR |
-                        EDMA_ERR_CRBQ_PAR | EDMA_ERR_CRPB_PAR |
+                        EDMA_ERR_CRQB_PAR | EDMA_ERR_CRPB_PAR |
                         EDMA_ERR_INTRL_PAR)) {
                 err_mask |= AC_ERR_ATA_BUS;
                 action |= ATA_EH_HARDRESET;
@@ -1489,33 +1489,30 @@ static void mv_intr_edma(struct ata_port *ap)
 
         while (1) {
                 u16 status;
+                unsigned int tag;
 
                 /* get s/w response queue last-read pointer, and compare */
                 out_index = pp->resp_idx & MV_MAX_Q_DEPTH_MASK;
                 if (in_index == out_index)
                         break;
 
-                 
                 /* 50xx: get active ATA command */
                 if (IS_GEN_I(hpriv)) 
-                        qc = ata_qc_from_tag(ap, ap->active_tag);
+                        tag = ap->active_tag;
 
-                /* 60xx: get active ATA command via tag, to enable support
-                 * for queueing.  this works transparently for queued and
-                 * non-queued modes.
+                /* Gen II/IIE: get active ATA command via tag, to enable
+                 * support for queueing.  this works transparently for
+                 * queued and non-queued modes.
                  */
-                else {
-                        unsigned int tag;
+                else if (IS_GEN_II(hpriv))
+                        tag = (le16_to_cpu(pp->crpb[out_index].id)
+                                >> CRPB_IOID_SHIFT_6) & 0x3f;
 
-                        if (IS_GEN_II(hpriv))
-                                tag = (le16_to_cpu(pp->crpb[out_index].id)
-                                        >> CRPB_IOID_SHIFT_6) & 0x3f;
-                        else
-                                tag = (le16_to_cpu(pp->crpb[out_index].id)
-                                        >> CRPB_IOID_SHIFT_7) & 0x3f;
+                else /* IS_GEN_IIE */
+                        tag = (le16_to_cpu(pp->crpb[out_index].id)
+                                >> CRPB_IOID_SHIFT_7) & 0x3f;
 
-                        qc = ata_qc_from_tag(ap, tag);
-                }
+                qc = ata_qc_from_tag(ap, tag);
 
                 /* lower 8 bits of status are EDMA_ERR_IRQ_CAUSE_OFS
                  * bits (WARNING: might not necessarily be associated