UPSTREAM: mmc-utils: add ability to enable/disable optional eMMC cache

The MMC4.5 specification added an optional cache for eMMC devices.
This change will add the ability to enable/disable the cache.

Signed-off-by: Al Cooper <acooperx@gmail.com>
Signed-off-by: Chris Ball <chris@printf.net>
(cherry picked from commit d0b46442b50794217e53b2455c1344c548d9d088)
Signed-off-by: Gwendal Grignou <gwendal@chromium.org>

BUG=none
TEST=Compiled, Installed on gnawty

Change-Id: I0d9e12abbd2b29bad564b869392ba2b0c51e246e
Reviewed-on: https://chromium-review.googlesource.com/338082
Commit-Ready: Gwendal Grignou <gwendal@chromium.org>
Tested-by: Gwendal Grignou <gwendal@chromium.org>
Reviewed-by: Grant Grundler <grundler@chromium.org>
diff --git a/mmc.c b/mmc.c
index 16fe02a..284cdb9 100644
--- a/mmc.c
+++ b/mmc.c
@@ -174,6 +174,18 @@
 		  "    mmc rpmb write-block /dev/mmcblk0rpmb 0x02 - -",
 	  NULL
 	},
+	{ do_cache_en, -1,
+	  "cache enable", "<device>\n"
+		"Enable the eMMC cache feature on <device>.\n"
+		"NOTE! The cache is an optional feature on devices >= eMMC4.5.",
+	  NULL
+	},
+	{ do_cache_dis, -1,
+	  "cache disable", "<device>\n"
+		"Disable the eMMC cache feature on <device>.\n"
+		"NOTE! The cache is an optional feature on devices >= eMMC4.5.",
+	  NULL
+	},
 	{ 0, 0, 0, 0 }
 };