sdhci-bcm2708: replace busy-waiting DMA sync by Auto-CMD12

Busy-waiting for the end of a DMA request is very bad, especially
because many SD cards are very slow. It's a much better idea to
delegate this waiting to the SDHCI controller, which can do this
easily with the Auto-CMD12 feature. This seems to be available and
work just fine on the Arasan controller, so enable it, and scrap the
sync-after-DMA code.

Author: grigorig

drivers/mmc/host/sdhci-bcm2708.c

@@ -52,7 +52,6 @@
 #undef CONFIG_MMC_SDHCI_BCM2708_DMA
 #define CONFIG_MMC_SDHCI_BCM2708_DMA y
 
-#define USE_SYNC_AFTER_DMA
 #ifdef CONFIG_MMC_SDHCI_BCM2708_DMA
 /* #define CHECK_DMA_USE */
 #endif
@@ -832,34 +831,6 @@ static void sdhci_bcm2708_dma_complete_irq(struct sdhci_host *host,
 						SDHCI_INT_SPACE_AVAIL);
 		}
 	} else {
-#ifdef USE_SYNC_AFTER_DMA
-		/* On the Arasan controller the stop command (which will be
-		   scheduled after this completes) does not seem to work
-		   properly if we allow it to be issued when we are
-		   transferring data to/from the SD card.
-		   We get CRC and DEND errors unless we wait for
-		   the SD controller to finish reading/writing to the card. */
-		u32 state_mask;
-		int timeout=5000;
-
-		DBG("PDMA over - sync card\n");
-		if (data->flags & MMC_DATA_READ)
-			state_mask = SDHCI_DOING_READ;
-		else
-			state_mask = SDHCI_DOING_WRITE;
-
-		while (0 != (sdhci_bcm2708_raw_readl(host, SDHCI_PRESENT_STATE) 
-			& state_mask) && --timeout > 0)
-		{
-			udelay(30);
-			continue;
-		}
-		if (timeout <= 0)
-			printk(KERN_ERR"%s: final %s to SD card still "
-			       "running\n",
-			       mmc_hostname(host->mmc),
-			       data->flags & MMC_DATA_READ? "read": "write");
-#endif
 		if (host_priv->complete) {
 			(*host_priv->complete)(host);
 			DBG("PDMA %s complete\n",
@@ -1315,7 +1286,8 @@ static int __devinit sdhci_bcm2708_probe(struct platform_device *pdev)
 		       SDHCI_QUIRK_DATA_TIMEOUT_USES_SDCLK |
 		       SDHCI_QUIRK_BROKEN_TIMEOUT_VAL |
                SDHCI_QUIRK_MISSING_CAPS |
-               SDHCI_QUIRK_NO_HISPD_BIT;
+               SDHCI_QUIRK_NO_HISPD_BIT |
+               SDHCI_QUIRK_MULTIBLOCK_READ_ACMD12;
 
 #ifdef CONFIG_MMC_SDHCI_BCM2708_DMA
 	host->flags = SDHCI_USE_PLATDMA;