sdhci: handle dma boundary interrupts

When the device hits certain memory boundaries, it signals an
interrupt and expects to be serviced. We don't need the feature
but we need to make sure the device doesn't stall.

Signed-off-by: Pierre Ossman <drzeus@drzeus.cx>

drivers/mmc/host/sdhci.c

@@ -963,6 +963,15 @@ static void sdhci_data_irq(struct sdhci_host *host, u32 intmask)
 		if (intmask & (SDHCI_INT_DATA_AVAIL | SDHCI_INT_SPACE_AVAIL))
 			sdhci_transfer_pio(host);
 
+		/*
+		 * We currently don't do anything fancy with DMA
+		 * boundaries, but as we can't disable the feature
+		 * we need to at least restart the transfer.
+		 */
+		if (intmask & SDHCI_INT_DMA_END)
+			writel(readl(host->ioaddr + SDHCI_DMA_ADDRESS),
+				host->ioaddr + SDHCI_DMA_ADDRESS);
+
 		if (intmask & SDHCI_INT_DATA_END)
 			sdhci_finish_data(host);
 	}