From 1de06b9fa5871b75012307ea736c8a43edf5a888 Mon Sep 17 00:00:00 2001
From: Jean-Jacques Hiblot <jjhiblot@ti.com>
Date: Thu, 30 Nov 2017 17:43:58 +0100
Subject: [PATCH] mmc: fix for old MMCs (below version 4)

The ext_csd is allocated only for MMC above version 4. The compare will
crash or fail for older MMCs.

Signed-off-by: Jean-Jacques Hiblot <jjhiblot@ti.com>
---
 drivers/mmc/mmc.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/mmc/mmc.c b/drivers/mmc/mmc.c
index 0ebcc45516..2a58031c19 100644
--- a/drivers/mmc/mmc.c
+++ b/drivers/mmc/mmc.c
@@ -1657,6 +1657,9 @@ static int mmc_read_and_compare_ext_csd(struct mmc *mmc)
 	const u8 *ext_csd = mmc->ext_csd;
 	ALLOC_CACHE_ALIGN_BUFFER(u8, test_csd, MMC_MAX_BLOCK_LEN);
 
+	if (mmc->version < MMC_VERSION_4)
+		return 0;
+
 	err = mmc_send_ext_csd(mmc, test_csd);
 	if (err)
 		return err;
-- 
2.39.5