mmc: owl_mmc: Do not dereference data before NULL check

In owl_mmc_prepare_data there is a NULL check for the pointer data but
it happens after data has already been dereferenced. Refactor the code
so that the NULL check happens before any code dereferences data.

This issue was found by Smatch.

Signed-off-by: Andrew Goodbody <andrew.goodbody@linaro.org>

diff --git a/drivers/mmc/owl_mmc.c b/drivers/mmc/owl_mmc.c
index bd4906f..c18807b 100644 (file)
--- a/drivers/mmc/owl_mmc.c
+++ b/drivers/mmc/owl_mmc.c
@@ -135,19 +135,19 @@ static void owl_mmc_prepare_data(struct owl_mmc_priv *priv,
 
        setbits_le32(priv->reg_base + OWL_REG_SD_EN, OWL_SD_EN_BSEL);
 
-       writel(data->blocks, priv->reg_base + OWL_REG_SD_BLK_NUM);
-       writel(data->blocksize, priv->reg_base + OWL_REG_SD_BLK_SIZE);
-       total = data->blocksize * data->blocks;
-
-       if (total < 512)
-               writel(total, priv->reg_base + OWL_REG_SD_BUF_SIZE);
-       else
-               writel(512, priv->reg_base + OWL_REG_SD_BUF_SIZE);
-
        /* DMA STOP */
        writel(0x0, SD_DMA_CHANNEL(priv->dma_channel, 0) + DMA_START);
 
        if (data) {
+               writel(data->blocks, priv->reg_base + OWL_REG_SD_BLK_NUM);
+               writel(data->blocksize, priv->reg_base + OWL_REG_SD_BLK_SIZE);
+               total = data->blocksize * data->blocks;
+
+               if (total < 512)
+                       writel(total, priv->reg_base + OWL_REG_SD_BUF_SIZE);
+               else
+                       writel(512, priv->reg_base + OWL_REG_SD_BUF_SIZE);
+
                if (data->flags == MMC_DATA_READ) {
                        buf = (ulong) (data->dest);
                        owl_dma_config(priv, (ulong) priv->reg_base +