ide: ->ide_dma_clear_irq() -> ->clear_irq()

* Rename ->ide_dma_clear_irq method to ->clear_irq
  and move it from ide_hwif_t to struct ide_port_ops.

* Move ->waiting_for_dma check inside ->clear_irq method.

* Move ->dma_base check inside ->clear_irq method.

piix.c:
* Add ich_port_ops and remove init_hwif_ich() wrapper.

There should be no functional changes caused by this patch.

Acked-by: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>

1 files changed, 23 insertions, 16 deletions

diff --git a/drivers/ide/pci/piix.c b/drivers/ide/pci/piix.c
index a909684ee61b..56feb939f82a 100644
--- a/drivers/ide/pci/piix.c
+++ b/drivers/ide/pci/piix.c
@@ -215,17 +215,26 @@ static unsigned int init_chipset_ich(struct pci_dev *dev)
 }
 
 /**
- *	piix_dma_clear_irq	-	clear BMDMA status
- *	@drive: IDE drive to clear
+ *	ich_clear_irq	-	clear BMDMA status
+ *	@drive: IDE drive
  *
- *	Called from ide_intr() for PIO interrupts
- *	to clear BMDMA status as needed by ICHx
+ *	ICHx contollers set DMA INTR no matter DMA or PIO.
+ *	BMDMA status might need to be cleared even for
+ *	PIO interrupts to prevent spurious/lost IRQ.
  */
-static void piix_dma_clear_irq(ide_drive_t *drive)
+static void ich_clear_irq(ide_drive_t *drive)
 {
 	ide_hwif_t *hwif = HWIF(drive);
 	u8 dma_stat;
 
+	/*
+	 * ide_dma_end() needs BMDMA status for error checking.
+	 * So, skip clearing BMDMA status here and leave it
+	 * to ide_dma_end() if this is DMA interrupt.
+	 */
+	if (drive->waiting_for_dma || hwif->dma_base == 0)
+		return;
+
 	/* clear the INTR & ERROR bits */
 	dma_stat = inb(hwif->dma_base + ATA_DMA_STATUS);
 	/* Should we force the bit as well ? */
@@ -293,21 +302,19 @@ static void __devinit init_hwif_piix(ide_hwif_t *hwif)
 		hwif->ultra_mask = hwif->mwdma_mask = hwif->swdma_mask = 0;
 }
 
-static void __devinit init_hwif_ich(ide_hwif_t *hwif)
-{
-	init_hwif_piix(hwif);
-
-	/* ICHx need to clear the BMDMA status for all interrupts */
-	if (hwif->dma_base)
-		hwif->ide_dma_clear_irq = &piix_dma_clear_irq;
-}
-
 static const struct ide_port_ops piix_port_ops = {
 	.set_pio_mode		= piix_set_pio_mode,
 	.set_dma_mode		= piix_set_dma_mode,
 	.cable_detect		= piix_cable_detect,
 };
 
+static const struct ide_port_ops ich_port_ops = {
+	.set_pio_mode		= piix_set_pio_mode,
+	.set_dma_mode		= piix_set_dma_mode,
+	.clear_irq		= ich_clear_irq,
+	.cable_detect		= piix_cable_detect,
+};
+
 #ifndef CONFIG_IA64
  #define IDE_HFLAGS_PIIX IDE_HFLAG_LEGACY_IRQS
 #else
@@ -331,9 +338,9 @@ static const struct ide_port_ops piix_port_ops = {
 	{ \
 		.name		= DRV_NAME, \
 		.init_chipset	= init_chipset_ich, \
-		.init_hwif	= init_hwif_ich, \
+		.init_hwif	= init_hwif_piix, \
 		.enablebits	= {{0x41,0x80,0x80}, {0x43,0x80,0x80}}, \
-		.port_ops	= &piix_port_ops, \
+		.port_ops	= &ich_port_ops, \
 		.host_flags	= IDE_HFLAGS_PIIX, \
 		.pio_mask	= ATA_PIO4, \
 		.swdma_mask	= ATA_SWDMA2_ONLY, \