On 5/9/2012 8:18 PM, Saugata Das wrote:
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>
---
mmc.c | 6 ++++++
mmc.h | 2 ++
mmc_cmds.c | 42 ++++++++++++++++++++++++++++++++++++++++++
mmc_cmds.h | 1 +
4 files changed, 51 insertions(+), 0 deletions(-)
diff --git a/mmc.c b/mmc.c
index c27fc24..43b95aa 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_emulation, -1,
can we add good name? which emulation we are disabling? It's 512B
emulation mode, we are disabling.
+ "disable 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..a2050fa 100644
--- a/mmc.h
+++ b/mmc.h
@@ -35,6 +35,8 @@
#define EXT_CSD_PART_SWITCH_TIME 199
#define EXT_CSD_BOOT_CFG 179
#define EXT_CSD_BOOT_WP 173
+#define EXT_CSD_NATIVE_SECTOR_SIZE 63 /* R */
+#define EXT_CSD_NATIVE_SECTOR 62 /* R/W */
Can we name this as EXT_CSD_USE_NATIVE_SECTOR?
/*
* EXT_CSD field definitions
diff --git a/mmc_cmds.c b/mmc_cmds.c
index 4562cef..2713ccd 100644
--- a/mmc_cmds.c
+++ b/mmc_cmds.c
@@ -168,6 +168,48 @@ int do_writeprotect_set(int nargs, char **argv)
return ret;
}
+
+int do_disable_emulation(int nargs, char **argv)
+{
+ __u8 ext_csd[512], native_sector_size;
+ 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);
+ }
+
+ native_sector_size = ext_csd[EXT_CSD_NATIVE_SECTOR_SIZE];
+
+ if (native_sector_size) {
+ ret = write_extcsd_value(fd, EXT_CSD_NATIVE_SECTOR, 1);
Just curious, how are we going to power cycle the device after setting
the USE_NATIVE_SECTOR? because DATA_SECTOR_SIZE won't be changed to 4K
until we explicitly power cycle after setting this field.
+
+ if (ret) {
+ fprintf(stderr, "Could not write 0x%02x to "
+ "EXT_CSD[%d] in %s\n",
+ 1, EXT_CSD_BOOT_WP, device);
+ exit(1);
+ }
+ } else {
+ printf("MMC does not support 4KB native sector\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..dd107d5 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_emulation(int nargs, char **argv);
--
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