scc_pata: bugfix for checking DMA IRQ status

On Tuesday 27 February 2007, Akira Iguchi wrote:
>
> But since I sent the first patch, I found a bug for checking DMA IRQ status.
> (http://www.spinics.net/lists/linux-ide/msg06903.html)
> Then I sent the fixed patch for libata only. So my drivers/ide patch
> still has same bug and I want to fix it, too.
>
> The following patch fixes this bug. Please apply this patch.

From: Akira Iguchi <akira2.iguchi@toshiba.co.jp>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>

1 files changed, 27 insertions, 0 deletions

diff --git a/drivers/ide/ppc/scc_pata.c b/drivers/ide/ppc/scc_pata.c
index de64b022478b..f84bf791f72e 100644
--- a/drivers/ide/ppc/scc_pata.c
+++ b/drivers/ide/ppc/scc_pata.c
@@ -509,6 +509,32 @@ static int scc_ide_dma_end(ide_drive_t * drive)
         return __ide_dma_end(drive);
 }
 
+/* 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);
+
+        /* return 1 if INTR asserted */
+        if ((dma_stat & 4) == 4)
+                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)
+                return 1;
+
+        if (!drive->waiting_for_dma)
+                printk(KERN_WARNING "%s: (%s) called while not waiting\n",
+                        drive->name, __FUNCTION__);
+        return 0;
+}
+
 /**
  *      setup_mmio_scc  -       map CTRL/BMID region
  *      @dev: PCI device we are configuring
@@ -712,6 +738,7 @@ static void __devinit init_hwif_scc(ide_hwif_t *hwif)
         hwif->speedproc = scc_tune_chipset;
         hwif->tuneproc = scc_tuneproc;
         hwif->ide_dma_check = scc_config_drive_for_dma;
+        hwif->ide_dma_test_irq = scc_dma_test_irq;
 
         hwif->drives[0].autotune = IDE_TUNE_AUTO;
         hwif->drives[1].autotune = IDE_TUNE_AUTO;