[PATCH] sata_mv: deal with interrupt coalescing interrupts

In some systems, it is possible that the BIOS may have enabled interrupt coalescing
for the Marvell controllers which support it.  This patch adds code to detect/ack
interrupts from the chip's coalescing (combing) logic.
Signed-off-by: Mark Lord <liml@rtr.ca>
Signed-off-by: Jeff Garzik <jeff@garzik.org>

drivers/scsi/sata_mv.c

@@ -50,6 +50,12 @@ enum {
 
 	MV_PCI_REG_BASE		= 0,
 	MV_IRQ_COAL_REG_BASE	= 0x18000,	/* 6xxx part only */
+	MV_IRQ_COAL_CAUSE		= (MV_IRQ_COAL_REG_BASE + 0x08),
+	MV_IRQ_COAL_CAUSE_LO		= (MV_IRQ_COAL_REG_BASE + 0x88),
+	MV_IRQ_COAL_CAUSE_HI		= (MV_IRQ_COAL_REG_BASE + 0x8c),
+	MV_IRQ_COAL_THRESHOLD		= (MV_IRQ_COAL_REG_BASE + 0xcc),
+	MV_IRQ_COAL_TIME_THRESHOLD	= (MV_IRQ_COAL_REG_BASE + 0xd0),
+
 	MV_SATAHC0_REG_BASE	= 0x20000,
 	MV_FLASH_CTL		= 0x1046c,
 	MV_GPIO_PORT_CTL	= 0x104f0,
@@ -1448,6 +1454,7 @@ static irqreturn_t mv_interrupt(int irq, void *dev_instance,
 	struct ata_host_set *host_set = dev_instance;
 	unsigned int hc, handled = 0, n_hcs;
 	void __iomem *mmio = host_set->mmio_base;
+	struct mv_host_priv *hpriv;
 	u32 irq_stat;
 
 	irq_stat = readl(mmio + HC_MAIN_IRQ_CAUSE_OFS);
@@ -1469,6 +1476,17 @@ static irqreturn_t mv_interrupt(int irq, void *dev_instance,
 			handled++;
 		}
 	}
+
+	hpriv = host_set->private_data;
+	if (IS_60XX(hpriv)) {
+		/* deal with the interrupt coalescing bits */
+		if (irq_stat & (TRAN_LO_DONE | TRAN_HI_DONE | PORTS_0_7_COAL_DONE)) {
+			writelfl(0, mmio + MV_IRQ_COAL_CAUSE_LO);
+			writelfl(0, mmio + MV_IRQ_COAL_CAUSE_HI);
+			writelfl(0, mmio + MV_IRQ_COAL_CAUSE);
+		}
+	}
+
 	if (PCI_ERR & irq_stat) {
 		printk(KERN_ERR DRV_NAME ": PCI ERROR; PCI IRQ cause=0x%08x\n",
 		       readl(mmio + PCI_IRQ_CAUSE_OFS));