On 14 May 2012 16:09, Subhash Jadavani <subhashj@xxxxxxxxxxxxxx> wrote:
> 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.
>
Ok
>> + "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?
>
Ok
>>
>> /*
>> * 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.
>
I will add a "printf" instructing the user to power cycle the eMMC at
the end of the switch.
>> +
>> + 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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