[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>

2 files changed, 14 insertions, 0 deletions

diff --git a/drivers/mmc/sdhci.c b/drivers/mmc/sdhci.c
index 95fe0fdac484..302dd5bde751 100644
--- a/drivers/mmc/sdhci.c
+++ b/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.
          */
diff --git a/drivers/mmc/sdhci.h b/drivers/mmc/sdhci.h
index 8ed2a8973db6..b1aa3acf0906 100644
--- a/drivers/mmc/sdhci.h
+++ b/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 */