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>
diff --git a/mmc_cmds.c b/mmc_cmds.c
index bf3ff78..4aa0a11 100644
--- a/mmc_cmds.c
+++ b/mmc_cmds.c
@@ -98,7 +98,7 @@
void print_writeprotect_status(__u8 *ext_csd)
{
__u8 reg;
- __u8 ext_csd_rev = ext_csd[192];
+ __u8 ext_csd_rev = ext_csd[EXT_CSD_REV];
/* A43: reserved [174:0] */
if (ext_csd_rev >= 5) {
@@ -1014,7 +1014,7 @@
exit(1);
}
- ext_csd_rev = ext_csd[192];
+ ext_csd_rev = ext_csd[EXT_CSD_REV];
switch (ext_csd_rev) {
case 7:
@@ -1218,7 +1218,7 @@
if (reg & 0x01) printf(" HS eMMC @26MHz - at rated device voltage(s)\n");
printf("CSD structure version [CSD_STRUCTURE: 0x%02x]\n", ext_csd[194]);
- /* ext_csd_rev = ext_csd[192] (already done!!!) */
+ /* ext_csd_rev = ext_csd[EXT_CSD_REV] (already done!!!) */
printf("Command set [CMD_SET: 0x%02x]\n", ext_csd[191]);
printf("Command set revision [CMD_SET_REV: 0x%02x]\n", ext_csd[189]);
printf("Power class [POWER_CLASS: 0x%02x]\n", ext_csd[187]);
@@ -1971,3 +1971,64 @@
return ret;
}
+
+int do_cache_ctrl(int value, int nargs, char **argv)
+{
+ __u8 ext_csd[512];
+ int fd, ret;
+ char *device;
+
+ CHECK(nargs != 2, "Usage: mmc cache enable </path/to/mmcblkX>\n",
+ exit(1));
+
+ device = argv[1];
+
+ fd = open(device, O_RDWR);
+ if (fd < 0) {
+ perror("open");
+ exit(1);
+ }
+
+ ret = read_extcsd(fd, ext_csd);
+ if (ret) {
+ fprintf(stderr, "Could not read EXT_CSD from %s\n", device);
+ exit(1);
+ }
+
+ if (ext_csd[EXT_CSD_REV] < EXT_CSD_REV_V4_5) {
+ fprintf(stderr,
+ "The CACHE option is only availabe on devices >= "
+ "MMC 4.5 %s\n", device);
+ exit(1);
+ }
+
+ /* If the cache size is zero, this device does not have a cache */
+ if (!(ext_csd[EXT_CSD_CACHE_SIZE_3] ||
+ ext_csd[EXT_CSD_CACHE_SIZE_2] ||
+ ext_csd[EXT_CSD_CACHE_SIZE_1] ||
+ ext_csd[EXT_CSD_CACHE_SIZE_0])) {
+ fprintf(stderr,
+ "The CACHE option is not available on %s\n",
+ device);
+ exit(1);
+ }
+ ret = write_extcsd_value(fd, EXT_CSD_CACHE_CTRL, value);
+ if (ret) {
+ fprintf(stderr,
+ "Could not write 0x%02x to EXT_CSD[%d] in %s\n",
+ value, EXT_CSD_CACHE_CTRL, device);
+ exit(1);
+ }
+
+ return ret;
+}
+
+int do_cache_en(int nargs, char **argv)
+{
+ return do_cache_ctrl(1, nargs, argv);
+}
+
+int do_cache_dis(int nargs, char **argv)
+{
+ return do_cache_ctrl(0, nargs, argv);
+}