[MMC] sdhci: Test for invalid block size

The controller has an upper limit on the block size. Make sure we do not
cross it.
Signed-off-by: Pierre Ossman <drzeus@drzeus.cx>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

drivers/mmc/sdhci.c

@@ -328,6 +328,8 @@ static void sdhci_prepare_data(struct sdhci_host *host, struct mmc_data *data)
 
 	/* Sanity checks */
 	BUG_ON(data->blksz * data->blocks > 524288);
+	BUG_ON(data->blksz > host->max_block);
+	BUG_ON(data->blocks > 65535);
 
 	/* timeout in us */
 	target_timeout = data->timeout_ns / 1000 +
@@ -1158,6 +1160,15 @@ static int __devinit sdhci_probe_slot(struct pci_dev *pdev, int slot)
 	if (caps & SDHCI_TIMEOUT_CLK_UNIT)
 		host->timeout_clk *= 1000;
 
+	host->max_block = (caps & SDHCI_MAX_BLOCK_MASK) >> SDHCI_MAX_BLOCK_SHIFT;
+	if (host->max_block >= 3) {
+		printk(KERN_ERR "%s: Invalid maximum block size.\n",
+			host->slot_descr);
+		ret = -ENODEV;
+		goto unmap;
+	}
+	host->max_block = 512 << host->max_block;
+
 	/*
 	 * Set host parameters.
 	 */

drivers/mmc/sdhci.h

@@ -131,6 +131,8 @@
 #define  SDHCI_TIMEOUT_CLK_UNIT	0x00000080
 #define  SDHCI_CLOCK_BASE_MASK	0x00003F00
 #define  SDHCI_CLOCK_BASE_SHIFT	8
+#define  SDHCI_MAX_BLOCK_MASK	0x00030000
+#define  SDHCI_MAX_BLOCK_SHIFT  16
 #define  SDHCI_CAN_DO_DMA	0x00400000
 #define  SDHCI_CAN_VDD_330	0x01000000
 #define  SDHCI_CAN_VDD_300	0x02000000
@@ -161,6 +163,7 @@ struct sdhci_host {
 
 	unsigned int		max_clk;	/* Max possible freq (MHz) */
 	unsigned int		timeout_clk;	/* Timeout freq (KHz) */
+	unsigned int		max_block;	/* Max block size (bytes) */
 
 	unsigned int		clock;		/* Current clock (MHz) */
 	unsigned short		power;		/* Current voltage */