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>

1 files changed, 35 insertions, 15 deletions

diff --git a/drivers/ata/pata_scc.c b/drivers/ata/pata_scc.c
index 61502bc7bf1d..274fabfc90e1 100644
--- 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;