From: Saugata Das <saugata.das@xxxxxxxxxx>
In this patch, we add utility to disable emulation mode in the eMMC-4.5.
This is done to increase the data sector size to 4KB.
Signed-off-by: Saugata Das <saugata.das@xxxxxxxxxx>
changes in v2:
Review rework based on comments from Subhash
---
mmc.c | 6 ++++++
mmc.h | 10 ++++++++++
mmc_cmds.c | 51 +++++++++++++++++++++++++++++++++++++++++++++++++++
mmc_cmds.h | 1 +
4 files changed, 68 insertions(+), 0 deletions(-)
diff --git a/mmc.c b/mmc.c
index c27fc24..ebc7ab2 100644
--- a/mmc.c
+++ b/mmc.c
@@ -65,6 +65,12 @@ static struct Command commands[] = {
"Set the eMMC writeprotect status of <device>.",
NULL
},
+ { do_disable_512B_emulation, -1,
+ "disable 512B emulation", "<device>\n"
+ "Set the eMMC data sector size to 4KB by disabling emulation <device>.",
+ NULL
+ },
+
{ 0, 0, 0, 0 }
};
diff --git a/mmc.h b/mmc.h
index 3af36f1..34c31d3 100644
--- a/mmc.h
+++ b/mmc.h
@@ -35,6 +35,16 @@
#define EXT_CSD_PART_SWITCH_TIME 199
#define EXT_CSD_BOOT_CFG 179
#define EXT_CSD_BOOT_WP 173
+#define EXT_CSD_WR_REL_PARAM 166
+#define EXT_CSD_NATIVE_SECTOR_SIZE 63 /* R */
+#define EXT_CSD_USE_NATIVE_SECTOR 62 /* R/W */
+#define EXT_CSD_DATA_SECTOR_SIZE 61 /* R */
+
+/*
+ * WR_REL_PARAM field definitions
+ */
+#define HS_CTRL_REL (1<<0)
+#define EN_REL_WR (1<<2)
/*
* EXT_CSD field definitions
diff --git a/mmc_cmds.c b/mmc_cmds.c
index 4562cef..f0e64c9 100644
--- a/mmc_cmds.c
+++ b/mmc_cmds.c
@@ -168,6 +168,57 @@ int do_writeprotect_set(int nargs, char **argv)
return ret;
}
+
+int do_disable_512B_emulation(int nargs, char **argv)
+{
+ __u8 ext_csd[512], native_sector_size, data_sector_size, wr_rel_param;
+ int fd, ret;
+ char *device;
+
+ CHECK(nargs != 2, "Usage: mmc </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);
+ }
+
+ wr_rel_param = ext_csd[EXT_CSD_WR_REL_PARAM];
+ native_sector_size = ext_csd[EXT_CSD_NATIVE_SECTOR_SIZE];
+ data_sector_size = ext_csd[EXT_CSD_DATA_SECTOR_SIZE];
+
+ if (native_sector_size &&
+ !data_sector_size &&
+ (wr_rel_param & EN_REL_WR)) {
+ ret = write_extcsd_value(fd, EXT_CSD_USE_NATIVE_SECTOR, 1);
+
+ if (ret) {
+ fprintf(stderr, "Could not write 0x%02x to "
+ "EXT_CSD[%d] in %s\n",
+ 1, EXT_CSD_BOOT_WP, device);
+ exit(1);
+ }
+ printf("MMC disable 512B emulation successful\n"
+ "Now reset the device to switch to 4KB "
+ "native sector mode\n");
+ } else if (native_sector_size && data_sector_size) {
+ printf("MMC already disabled 512B emulation mode\n");
+ } else {
+ printf("MMC does not support disabling 512B emulation mode\n");
+ }
+
+ return ret;
+}
+
+
int do_read_extcsd(int nargs, char **argv)
{
__u8 ext_csd[512], ext_csd_rev, reg;
diff --git a/mmc_cmds.h b/mmc_cmds.h
index 66e9acb..56f46d7 100644
--- a/mmc_cmds.h
+++ b/mmc_cmds.h
@@ -19,3 +19,4 @@ int do_read_extcsd(int nargs, char **argv);
int do_write_extcsd(int nargs, char **argv);
int do_writeprotect_get(int nargs, char **argv);
int do_writeprotect_set(int nargs, char **argv);
+int do_disable_512B_emulation(int nargs, char **argv);
--
1.7.4.3
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