pata_scc.c: Workaround for errata A308

Workaround for errata A308: turn down the UDMA mode and retry
the DMA command when the data lost condition is detected.

Signed-off-by: Kou Ishizaki <kou.ishizaki@toshiba.co.jp>
Signed-off-by: Akira Iguchi <akira2.iguchi@toshiba.co.jp>
Signed-off-by: Jeff Garzik <jeff@garzik.org>

diff --git a/drivers/ata/pata_scc.c b/drivers/ata/pata_scc.c
index 61502bc..274fabf 100644 (file)
--- a/drivers/ata/pata_scc.c
+++ b/drivers/ata/pata_scc.c
@@ -238,6 +238,12 @@ static void scc_set_dmamode (struct ata_port *ap, struct ata_device *adev)
        else
                offset = 0;     /* 100MHz */
 
+       /* errata A308 workaround: limit ATAPI UDMA mode to UDMA4 */
+       if (adev->class == ATA_DEV_ATAPI && speed > XFER_UDMA_4) {
+               printk(KERN_INFO "%s: limit ATAPI UDMA to UDMA4\n", DRV_NAME);
+               speed = XFER_UDMA_4;
+       }
+
        if (speed >= XFER_UDMA_0)
                idx = speed - XFER_UDMA_0;
        else
@@ -724,22 +730,36 @@ static void scc_bmdma_stop (struct ata_queued_cmd *qc)
 
 static u8 scc_bmdma_status (struct ata_port *ap)
 {
-       u8 host_stat;
        void __iomem *mmio = ap->ioaddr.bmdma_addr;
-
-       host_stat = in_be32(mmio + SCC_DMA_STATUS);
-
-       /* Workaround for PTERADD: emulate DMA_INTR when
-        * - IDE_STATUS[ERR] = 1
-        * - INT_STATUS[INTRQ] = 1
-        * - DMA_STATUS[IORACTA] = 1
-        */
-       if (!(host_stat & ATA_DMA_INTR)) {
-               u32 int_status = in_be32(mmio + SCC_DMA_INTST);
-               if (ata_altstatus(ap) & ATA_ERR &&
-                   int_status & INTSTS_INTRQ &&
-                   host_stat & ATA_DMA_ACTIVE)
-                       host_stat |= ATA_DMA_INTR;
+       u8 host_stat = in_be32(mmio + SCC_DMA_STATUS);
+       u32 int_status = in_be32(mmio + SCC_DMA_INTST);
+       struct ata_queued_cmd *qc = ata_qc_from_tag(ap, ap->active_tag);
+       static int retry = 0;
+
+       /* return if IOS_SS is cleared */
+       if (!(in_be32(mmio + SCC_DMA_CMD) & ATA_DMA_START))
+               return host_stat;
+
+       /* errata A252,A308 workaround: Step4 */
+       if (ata_altstatus(ap) & ATA_ERR && int_status & INTSTS_INTRQ)
+               return (host_stat | ATA_DMA_INTR);
+
+       /* errata A308 workaround Step5 */
+       if (int_status & INTSTS_IOIRQS) {
+               host_stat |= ATA_DMA_INTR;
+
+               /* We don't check ATAPI DMA because it is limited to UDMA4 */
+               if ((qc->tf.protocol == ATA_PROT_DMA &&
+                    qc->dev->xfer_mode > XFER_UDMA_4)) {
+                       if (!(int_status & INTSTS_ACTEINT)) {
+                               printk(KERN_WARNING "ata%u: data lost occurred. (ACTEINT==0, retry:%d)\n",
+                                      ap->print_id, retry);
+                               host_stat |= ATA_DMA_ERR;
+                               if (retry++)
+                                       ap->udma_mask >>= 1;
+                       } else
+                               retry = 0;
+               }
        }
 
        return host_stat;