RE: [PATCH v2 2/2] [MMC-4.5] [MMC UTIL] Disable emulation

["Subhash Jadavani" <subhashj@xxxxxxxxxxxxxx>]

Thanks Saugata. 

Looks good to me.
Reviewed-by: Subhash Jadavani <subhashj@xxxxxxxxxxxxxx>

Regards,
Subhash

> -----Original Message-----
> From: linux-mmc-owner@xxxxxxxxxxxxxxx [mailto:linux-mmc-
> owner@xxxxxxxxxxxxxxx] On Behalf Of Saugata Das
> Sent: Thursday, May 17, 2012 4:32 PM
> To: linux-mmc@xxxxxxxxxxxxxxx
> Cc: patches@xxxxxxxxxx; saugata.das@xxxxxxxxxx; subhashj@xxxxxxxxxxxxxx;
> arnd.bergmann@xxxxxxxxxx; venkat@xxxxxxxxxx; lporzio@xxxxxxxxxx;
> linkinjeon@xxxxxxxxx
> Subject: [PATCH v2 2/2] [MMC-4.5] [MMC UTIL] Disable emulation
> 
> 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:
> 	Removed extra blank lines around do_disable_512B_emulation
> 	Review rework based on comments from Subhash
> ---
>  mmc.c      |    6 ++++++
>  mmc.h      |   10 ++++++++++
>  mmc_cmds.c |   49
> +++++++++++++++++++++++++++++++++++++++++++++++++
>  mmc_cmds.h |    1 +
>  4 files changed, 66 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..4bc1fd6 100644
> --- a/mmc_cmds.c
> +++ b/mmc_cmds.c
> @@ -168,6 +168,55 @@ 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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