mmc: sdhci: fix cache flush

Only flush the memory range needed.

Signed-off-by: Lei Wen <leiwen@marvell.com>

drivers/mmc/sdhci.c

@@ -196,7 +196,7 @@ int sdhci_send_command(struct mmc *mmc, struct mmc_cmd *cmd,
 
 	sdhci_writel(host, cmd->cmdarg, SDHCI_ARGUMENT);
 #ifdef CONFIG_MMC_SDMA
-	flush_cache(0, ~0);
+	flush_cache(start_addr, trans_bytes);
 #endif
 	sdhci_writew(host, SDHCI_MAKE_CMD(cmd->cmdidx, flags), SDHCI_COMMAND);
 	do {