mmc: sdhci: clean up interrupt handling

sdhci interrupt handling is a mess; there is a lot of code doing very
similar things.  Let's clean this up a bit:

1. set's clear down cmd, data and bus power interrupts in one go - we're
   always going to handle these.
2. use a do { } while () loop for looping while there are pending
   interrupts.
3. group clearing of bits in intmask into one place.

This results in the code becoming simpler and easier to read.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Tested-by: Markus Pargmann <mpa@pengutronix.de>
Tested-by: Stephen Warren <swarren@nvidia.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Chris Ball <chris@printf.net>

drivers/mmc/host/sdhci.c

@@ -2431,7 +2431,7 @@ static irqreturn_t sdhci_irq(int irq, void *dev_id)
 {
 	irqreturn_t result;
 	struct sdhci_host *host = dev_id;
-	u32 intmask, unexpected = 0;
+	u32 intmask, mask, unexpected = 0;
 	int cardint = 0, max_loops = 16;
 
 	spin_lock(&host->lock);
@@ -2442,13 +2442,17 @@ static irqreturn_t sdhci_irq(int irq, void *dev_id)
 	}
 
 	intmask = sdhci_readl(host, SDHCI_INT_STATUS);
-
 	if (!intmask || intmask == 0xffffffff) {
 		result = IRQ_NONE;
 		goto out;
 	}
 
-again:
+	do {
+		/* Clear selected interrupts. */
+		mask = intmask & (SDHCI_INT_CMD_MASK | SDHCI_INT_DATA_MASK |
+				  SDHCI_INT_BUS_POWER);
+		sdhci_writel(host, mask, SDHCI_INT_STATUS);
+
 		DBG("*** %s got interrupt: 0x%08x\n",
 			mmc_hostname(host->mmc), intmask);
 
@@ -2457,14 +2461,15 @@ static irqreturn_t sdhci_irq(int irq, void *dev_id)
 				      SDHCI_CARD_PRESENT;
 
 			/*
-		 * There is a observation on i.mx esdhc.  INSERT bit will be
-		 * immediately set again when it gets cleared, if a card is
-		 * inserted.  We have to mask the irq to prevent interrupt
-		 * storm which will freeze the system.  And the REMOVE gets
-		 * the same situation.
+			 * There is a observation on i.mx esdhc.  INSERT
+			 * bit will be immediately set again when it gets
+			 * cleared, if a card is inserted.  We have to mask
+			 * the irq to prevent interrupt storm which will
+			 * freeze the system.  And the REMOVE gets the
+			 * same situation.
 			 *
-		 * More testing are needed here to ensure it works for other
-		 * platforms though.
+			 * More testing are needed here to ensure it works
+			 * for other platforms though.
 			 */
 			sdhci_mask_irqs(host, present ? SDHCI_INT_CARD_INSERT :
 							SDHCI_INT_CARD_REMOVE);
@@ -2473,38 +2478,26 @@ static irqreturn_t sdhci_irq(int irq, void *dev_id)
 
 			sdhci_writel(host, intmask & (SDHCI_INT_CARD_INSERT |
 				     SDHCI_INT_CARD_REMOVE), SDHCI_INT_STATUS);
-		intmask &= ~(SDHCI_INT_CARD_INSERT | SDHCI_INT_CARD_REMOVE);
 			tasklet_schedule(&host->card_tasklet);
 		}
 
-	if (intmask & SDHCI_INT_CMD_MASK) {
-		sdhci_writel(host, intmask & SDHCI_INT_CMD_MASK,
-			SDHCI_INT_STATUS);
+		if (intmask & SDHCI_INT_CMD_MASK)
 			sdhci_cmd_irq(host, intmask & SDHCI_INT_CMD_MASK);
-	}
 
-	if (intmask & SDHCI_INT_DATA_MASK) {
-		sdhci_writel(host, intmask & SDHCI_INT_DATA_MASK,
-			SDHCI_INT_STATUS);
+		if (intmask & SDHCI_INT_DATA_MASK)
 			sdhci_data_irq(host, intmask & SDHCI_INT_DATA_MASK);
-	}
 
-	intmask &= ~(SDHCI_INT_CMD_MASK | SDHCI_INT_DATA_MASK);
-
-	intmask &= ~SDHCI_INT_ERROR;
-
-	if (intmask & SDHCI_INT_BUS_POWER) {
+		if (intmask & SDHCI_INT_BUS_POWER)
 			pr_err("%s: Card is consuming too much power!\n",
 				mmc_hostname(host->mmc));
-		sdhci_writel(host, SDHCI_INT_BUS_POWER, SDHCI_INT_STATUS);
-	}
-
-	intmask &= ~SDHCI_INT_BUS_POWER;
 
 		if (intmask & SDHCI_INT_CARD_INT)
 			cardint = 1;
 
-	intmask &= ~SDHCI_INT_CARD_INT;
+		intmask &= ~(SDHCI_INT_CARD_INSERT | SDHCI_INT_CARD_REMOVE |
+			     SDHCI_INT_CMD_MASK | SDHCI_INT_DATA_MASK |
+			     SDHCI_INT_ERROR | SDHCI_INT_BUS_POWER |
+			     SDHCI_INT_CARD_INT);
 
 		if (intmask) {
 			unexpected |= intmask;
@@ -2516,14 +2509,13 @@ static irqreturn_t sdhci_irq(int irq, void *dev_id)
 		intmask = sdhci_readl(host, SDHCI_INT_STATUS);
 
 		/*
-	 * If we know we'll call the driver to signal SDIO IRQ, disregard
-	 * further indications of Card Interrupt in the status to avoid a
-	 * needless loop.
+		 * If we know we'll call the driver to signal SDIO IRQ,
+		 * disregard further indications of Card Interrupt in
+		 * the status to avoid a needless loop.
 		 */
 		if (cardint)
 			intmask &= ~SDHCI_INT_CARD_INT;
-	if (intmask && --max_loops)
-		goto again;
+	} while (intmask && --max_loops);
 out:
 	spin_unlock(&host->lock);