sunxi: mmc: set transfer timeout according to byte_cnt.

Originally a timeout value of 2 seconds was used regardless of the size
of data to be transfered.  This prevented slow devices from working
correctly while there was no much gain for faster devices, e.g. it takes
3708ms for a transfer of uImage of size 1899008 bytes.

Signed-off-by: Yousong Zhou <yszhou4tech@gmail.com>
Acked-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>

drivers/mmc/sunxi_mmc.c

@@ -257,9 +257,11 @@ static int mmc_trans_data_by_cpu(struct mmc *mmc, struct mmc_data *data)
 	const uint32_t status_bit = reading ? SUNXI_MMC_STATUS_FIFO_EMPTY :
 					      SUNXI_MMC_STATUS_FIFO_FULL;
 	unsigned i;
-	unsigned byte_cnt = data->blocksize * data->blocks;
-	unsigned timeout_msecs = 2000;
 	unsigned *buff = (unsigned int *)(reading ? data->dest : data->src);
+	unsigned byte_cnt = data->blocksize * data->blocks;
+	unsigned timeout_msecs = byte_cnt >> 8;
+	if (timeout_msecs < 2000)
+		timeout_msecs = 2000;
 
 	/* Always read / write data through the CPU */
 	setbits_le32(&mmchost->reg->gctrl, SUNXI_MMC_GCTRL_ACCESS_BY_AHB);