Support enable/disable of eMMC H/W Reset function
(Note: one-time programmable fuse.)
$ mmc hwreset enable /dev/mmcblk0
$ mmc hwreset disable /dev/mmcblk0
diff --git a/mmc_cmds.c b/mmc_cmds.c
index 05d7e13..b407f65 100644
--- a/mmc_cmds.c
+++ b/mmc_cmds.c
@@ -280,6 +280,65 @@
return ret;
}
+int do_hwreset(int value, int nargs, char **argv)
+{
+ __u8 ext_csd[512];
+ int fd, ret;
+ char *device;
+
+ CHECK(nargs != 2, "Usage: mmc hwreset 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_RST_N_FUNCTION] & EXT_CSD_RST_N_EN_MASK) ==
+ EXT_CSD_HW_RESET_EN) {
+ fprintf(stderr,
+ "H/W Reset is already permanently enabled on %s\n",
+ device);
+ exit(1);
+ }
+ if ((ext_csd[EXT_CSD_RST_N_FUNCTION] & EXT_CSD_RST_N_EN_MASK) ==
+ EXT_CSD_HW_RESET_DIS) {
+ fprintf(stderr,
+ "H/W Reset is already permanently disabled on %s\n",
+ device);
+ exit(1);
+ }
+
+ ret = write_extcsd_value(fd, EXT_CSD_RST_N_FUNCTION, value);
+ if (ret) {
+ fprintf(stderr,
+ "Could not write 0x%02x to EXT_CSD[%d] in %s\n",
+ value, EXT_CSD_RST_N_FUNCTION, device);
+ exit(1);
+ }
+
+ return ret;
+}
+
+int do_hwreset_en(int nargs, char **argv)
+{
+ return do_hwreset(EXT_CSD_HW_RESET_EN, nargs, argv);
+}
+
+int do_hwreset_dis(int nargs, char **argv)
+{
+ return do_hwreset(EXT_CSD_HW_RESET_DIS, nargs, argv);
+}
+
int do_write_bkops_en(int nargs, char **argv)
{
__u8 ext_csd[512], value = 0;