[libata] sata_mv: Implement direct FIS transmission via mv_qc_issue_fis().

This is initially needed to work around NCQ errata,
whereby the READ_LOG_EXT command sometimes fails
when issued in the traditional (sff) fashion.

Portions of this code will likely be reused for
implementation of the target mode feature later on.

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 542e244..8cad3b2 100644 (file)
--- a/drivers/ata/sata_mv.c
+++ b/drivers/ata/sata_mv.c
@@ -1822,6 +1822,105 @@ static u8 mv_sff_check_status(struct ata_port *ap)
 }
 
 /**
+ *     mv_send_fis - Send a FIS, using the "Vendor-Unique FIS" register
+ *     @fis: fis to be sent
+ *     @nwords: number of 32-bit words in the fis
+ */
+static unsigned int mv_send_fis(struct ata_port *ap, u32 *fis, int nwords)
+{
+       void __iomem *port_mmio = mv_ap_base(ap);
+       u32 ifctl, old_ifctl, ifstat;
+       int i, timeout = 200, final_word = nwords - 1;
+
+       /* Initiate FIS transmission mode */
+       old_ifctl = readl(port_mmio + SATA_IFCTL_OFS);
+       ifctl = 0x100 | (old_ifctl & 0xf);
+       writelfl(ifctl, port_mmio + SATA_IFCTL_OFS);
+
+       /* Send all words of the FIS except for the final word */
+       for (i = 0; i < final_word; ++i)
+               writel(fis[i], port_mmio + VENDOR_UNIQUE_FIS_OFS);
+
+       /* Flag end-of-transmission, and then send the final word */
+       writelfl(ifctl | 0x200, port_mmio + SATA_IFCTL_OFS);
+       writelfl(fis[final_word], port_mmio + VENDOR_UNIQUE_FIS_OFS);
+
+       /*
+        * Wait for FIS transmission to complete.
+        * This typically takes just a single iteration.
+        */
+       do {
+               ifstat = readl(port_mmio + SATA_IFSTAT_OFS);
+       } while (!(ifstat & 0x1000) && --timeout);
+
+       /* Restore original port configuration */
+       writelfl(old_ifctl, port_mmio + SATA_IFCTL_OFS);
+
+       /* See if it worked */
+       if ((ifstat & 0x3000) != 0x1000) {
+               ata_port_printk(ap, KERN_WARNING,
+                               "%s transmission error, ifstat=%08x\n",
+                               __func__, ifstat);
+               return AC_ERR_OTHER;
+       }
+       return 0;
+}
+
+/**
+ *     mv_qc_issue_fis - Issue a command directly as a FIS
+ *     @qc: queued command to start
+ *
+ *     Note that the ATA shadow registers are not updated
+ *     after command issue, so the device will appear "READY"
+ *     if polled, even while it is BUSY processing the command.
+ *
+ *     So we use a status hook to fake ATA_BUSY until the drive changes state.
+ *
+ *     Note: we don't get updated shadow regs on *completion*
+ *     of non-data commands. So avoid sending them via this function,
+ *     as they will appear to have completed immediately.
+ *
+ *     GEN_IIE has special registers that we could get the result tf from,
+ *     but earlier chipsets do not.  For now, we ignore those registers.
+ */
+static unsigned int mv_qc_issue_fis(struct ata_queued_cmd *qc)
+{
+       struct ata_port *ap = qc->ap;
+       struct mv_port_priv *pp = ap->private_data;
+       struct ata_link *link = qc->dev->link;
+       u32 fis[5];
+       int err = 0;
+
+       ata_tf_to_fis(&qc->tf, link->pmp, 1, (void *)fis);
+       err = mv_send_fis(ap, fis, sizeof(fis) / sizeof(fis[0]));
+       if (err)
+               return err;
+
+       switch (qc->tf.protocol) {
+       case ATAPI_PROT_PIO:
+               pp->pp_flags |= MV_PP_FLAG_FAKE_ATA_BUSY;
+               /* fall through */
+       case ATAPI_PROT_NODATA:
+               ap->hsm_task_state = HSM_ST_FIRST;
+               break;
+       case ATA_PROT_PIO:
+               pp->pp_flags |= MV_PP_FLAG_FAKE_ATA_BUSY;
+               if (qc->tf.flags & ATA_TFLAG_WRITE)
+                       ap->hsm_task_state = HSM_ST_FIRST;
+               else
+                       ap->hsm_task_state = HSM_ST;
+               break;
+       default:
+               ap->hsm_task_state = HSM_ST_LAST;
+               break;
+       }
+
+       if (qc->tf.flags & ATA_TFLAG_POLLING)
+               ata_pio_queue_task(ap, qc, 0);
+       return 0;
+}
+
+/**
  *      mv_qc_issue - Initiate a command to the host
  *      @qc: queued command to start
  *
@@ -1896,6 +1995,23 @@ static unsigned int mv_qc_issue(struct ata_queued_cmd *qc)
        mv_stop_edma(ap);
        mv_clear_and_enable_port_irqs(ap, mv_ap_base(ap), port_irqs);
        mv_pmp_select(ap, qc->dev->link->pmp);
+
+       if (qc->tf.command == ATA_CMD_READ_LOG_EXT) {
+               struct mv_host_priv *hpriv = ap->host->private_data;
+               /*
+                * Workaround for 88SX60x1 FEr SATA#25 (part 2).
+                * 
+                * After any NCQ error, the READ_LOG_EXT command
+                * from libata-eh *must* use mv_qc_issue_fis().
+                * Otherwise it might fail, due to chip errata.
+                *
+                * Rather than special-case it, we'll just *always*
+                * use this method here for READ_LOG_EXT, making for
+                * easier testing.
+                */
+               if (IS_GEN_II(hpriv))
+                       return mv_qc_issue_fis(qc);
+       }
        return ata_sff_qc_issue(qc);
 }