diff --git a/drivers/mmc/mmci.c b/drivers/mmc/mmci.c
index 1886562abdd40100956cc50b12962bd91bf484d3..8419489e7744fcc9eb9d6567193d0b202ef3e6ac 100644
--- a/drivers/mmc/mmci.c
+++ b/drivers/mmc/mmci.c
@@ -69,12 +69,13 @@ static void mmci_start_data(struct mmci_host *host, struct mmc_data *data)
 	unsigned int datactrl, timeout, irqmask;
 	unsigned long long clks;
 	void __iomem *base;
+	int blksz_bits;
 
 	DBG(host, "blksz %04x blks %04x flags %08x\n",
-	    1 << data->blksz_bits, data->blocks, data->flags);
+	    data->blksz, data->blocks, data->flags);
 
 	host->data = data;
-	host->size = data->blocks << data->blksz_bits;
+	host->size = data->blksz;
 	host->data_xfered = 0;
 
 	mmci_init_sg(host, data);
@@ -88,7 +89,10 @@ static void mmci_start_data(struct mmci_host *host, struct mmc_data *data)
 	writel(timeout, base + MMCIDATATIMER);
 	writel(host->size, base + MMCIDATALENGTH);
 
-	datactrl = MCI_DPSM_ENABLE | data->blksz_bits << 4;
+	blksz_bits = ffs(data->blksz) - 1;
+	BUG_ON(1 << blksz_bits != data->blksz);
+
+	datactrl = MCI_DPSM_ENABLE | blksz_bits << 4;
 	if (data->flags & MMC_DATA_READ) {
 		datactrl |= MCI_DPSM_DIRECTION;
 		irqmask = MCI_RXFIFOHALFFULLMASK;
@@ -145,7 +149,7 @@ mmci_data_irq(struct mmci_host *host, struct mmc_data *data,
 	      unsigned int status)
 {
 	if (status & MCI_DATABLOCKEND) {
-		host->data_xfered += 1 << data->blksz_bits;
+		host->data_xfered += data->blksz;
 	}
 	if (status & (MCI_DATACRCFAIL|MCI_DATATIMEOUT|MCI_TXUNDERRUN|MCI_RXOVERRUN)) {
 		if (status & MCI_DATACRCFAIL)