scc_pata.c: Workaround for errata A308 (take 2)

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

take2:
udma_filter() hook is used to limit ATAPI UDMA mode.

Signed-off-by: Kou Ishizaki <kou.ishizaki@toshiba.co.jp>
Signed-off-by: Akira Iguchi <akira2.iguchi@toshiba.co.jp>
Cc: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>

1 files changed, 54 insertions, 13 deletions

diff --git a/drivers/ide/pci/scc_pata.c b/drivers/ide/pci/scc_pata.c
index a96333c74bf1..fd4b1a24ecab 100644
--- a/drivers/ide/pci/scc_pata.c
+++ b/drivers/ide/pci/scc_pata.c
@@ -401,6 +401,33 @@ static int scc_ide_dma_end(ide_drive_t * drive)
         ide_hwif_t *hwif = HWIF(drive);
         unsigned long intsts_port = hwif->dma_base + 0x014;
         u32 reg;
+        int dma_stat, data_loss = 0;
+        static int retry = 0;
+
+        /* errata A308 workaround: Step5 (check data loss) */
+        /* We don't check non ide_disk because it is limited to UDMA4 */
+        if (!(in_be32((void __iomem *)IDE_ALTSTATUS_REG) & ERR_STAT) &&
+            drive->media == ide_disk && drive->current_speed > XFER_UDMA_4) {
+                reg = in_be32((void __iomem *)intsts_port);
+                if (!(reg & INTSTS_ACTEINT)) {
+                        printk(KERN_WARNING "%s: operation failed (transfer data loss)\n",
+                               drive->name);
+                        data_loss = 1;
+                        if (retry++) {
+                                struct request *rq = HWGROUP(drive)->rq;
+                                int unit;
+                                /* ERROR_RESET and drive->crc_count are needed
+                                 * to reduce DMA transfer mode in retry process.
+                                 */
+                                if (rq)
+                                        rq->errors |= ERROR_RESET;
+                                for (unit = 0; unit < MAX_DRIVES; unit++) {
+                                        ide_drive_t *drive = &hwif->drives[unit];
+                                        drive->crc_count++;
+                                }
+                        }
+                }
+        }
 
         while (1) {
                 reg = in_be32((void __iomem *)intsts_port);
@@ -469,27 +496,25 @@ static int scc_ide_dma_end(ide_drive_t * drive)
                 break;
         }
 
-        return __ide_dma_end(drive);
+        dma_stat = __ide_dma_end(drive);
+        if (data_loss)
+                dma_stat |= 2; /* emulate DMA error (to retry command) */
+        return dma_stat;
 }
 
 /* returns 1 if dma irq issued, 0 otherwise */
 static int scc_dma_test_irq(ide_drive_t *drive)
 {
-        ide_hwif_t *hwif        = HWIF(drive);
-        u8 dma_stat             = hwif->INB(hwif->dma_status);
+        ide_hwif_t *hwif = HWIF(drive);
+        u32 int_stat = in_be32((void __iomem *)hwif->dma_base + 0x014);
 
-        /* return 1 if INTR asserted */
-        if ((dma_stat & 4) == 4)
+        /* SCC errata A252,A308 workaround: Step4 */
+        if ((in_be32((void __iomem *)IDE_ALTSTATUS_REG) & ERR_STAT) &&
+            (int_stat & INTSTS_INTRQ))
                 return 1;
 
-        /* Workaround for PTERADD: emulate DMA_INTR when
-         * - IDE_STATUS[ERR] = 1
-         * - INT_STATUS[INTRQ] = 1
-         * - DMA_STATUS[IORACTA] = 1
-         */
-        if (in_be32((void __iomem *)IDE_ALTSTATUS_REG) & ERR_STAT &&
-            in_be32((void __iomem *)(hwif->dma_base + 0x014)) & INTSTS_INTRQ &&
-                dma_stat & 1)
+        /* SCC errata A308 workaround: Step5 (polling IOIRQS) */
+        if (int_stat & INTSTS_IOIRQS)
                 return 1;
 
         if (!drive->waiting_for_dma)
@@ -498,6 +523,21 @@ static int scc_dma_test_irq(ide_drive_t *drive)
         return 0;
 }
 
+static u8 scc_udma_filter(ide_drive_t *drive)
+{
+        ide_hwif_t *hwif = drive->hwif;
+        u8 mask = hwif->ultra_mask;
+
+        /* errata A308 workaround: limit non ide_disk drive to UDMA4 */
+        if ((drive->media != ide_disk) && (mask & 0xE0)) {
+                printk(KERN_INFO "%s: limit %s to UDMA4\n",
+                       SCC_PATA_NAME, drive->name);
+                mask = 0x1F;
+        }
+
+        return mask;
+}
+
 /**
  *      setup_mmio_scc  -       map CTRL/BMID region
  *      @dev: PCI device we are configuring
@@ -702,6 +742,7 @@ static void __devinit init_hwif_scc(ide_hwif_t *hwif)
         hwif->tuneproc = scc_tuneproc;
         hwif->ide_dma_check = scc_config_drive_for_dma;
         hwif->ide_dma_test_irq = scc_dma_test_irq;
+        hwif->udma_filter = scc_udma_filter;
 
         hwif->drives[0].autotune = IDE_TUNE_AUTO;
         hwif->drives[1].autotune = IDE_TUNE_AUTO;