[PATCH v2] cmd: mmc: Add mmc reg read command for reading card registers

Jaehoon Chung jh80.chung at samsung.com
Tue Oct 31 07:08:23 CET 2023


Hi Marek,

On 10/10/23 21:47, Marek Vasut wrote:
> Add extension to the 'mmc' command to read out the card registers.
> Currently, only the eMMC OCR/CID/CSD/EXTCSD/RCA/DSR register are
> supported. A register value can either be displayed or read into
> an environment variable.
> 
> Signed-off-by: Marek Vasut <marex at denx.de>
> ---
> Cc: Abdellatif El Khlifi <abdellatif.elkhlifi at arm.com>
> Cc: Heinrich Schuchardt <xypron.glpk at gmx.de>
> Cc: Ilias Apalodimas <ilias.apalodimas at linaro.org>
> Cc: Jaehoon Chung <jh80.chung at samsung.com>
> Cc: Ramon Fried <rfried.dev at gmail.com>
> Cc: Roger Knecht <rknecht at pm.me>
> Cc: Sean Edmond <seanedmond at microsoft.com>
> Cc: Simon Glass <sjg at chromium.org>
> Cc: Tobias Waldekranz <tobias at waldekranz.com>

Looks good to me. I have tested with your patch on my target.

mmc reg read cid all
CID[0]: 0x15010042
=> mmc reg read extcsd all
EXT_CSD:
000:  00 00 00 00 00 00 00 00 00 00
010:  00 00 00 00 00 00 39 00 00 00
..[snip]..

Tested-by: Jaehoon Chung <jh80.chung at samsung.com>
Reviewed-by: Jaehoon Chung <jh80.chung at samsung.com>

Best Regards,
Jaehoon Chung

> ---
> V2: - Update documentation
> ---
>  cmd/Kconfig           |  8 ++++
>  cmd/mmc.c             | 96 +++++++++++++++++++++++++++++++++++++++++++
>  doc/usage/cmd/mmc.rst | 26 ++++++++++++
>  3 files changed, 130 insertions(+)
> 
> diff --git a/cmd/Kconfig b/cmd/Kconfig
> index 6470b138d2f..dcd99757a1e 100644
> --- a/cmd/Kconfig
> +++ b/cmd/Kconfig
> @@ -1307,6 +1307,14 @@ config CMD_BKOPS_ENABLE
>  	  on a eMMC device. The feature is optionally available on eMMC devices
>  	  conforming to standard >= 4.41.
>  
> +config CMD_MMC_REG
> +	bool "Enable support for reading card registers in the mmc command"
> +	depends on CMD_MMC
> +	default n
> +	help
> +	  Enable the commands for reading card registers. This is useful
> +	  mostly for debugging or extracting details from the card.
> +
>  config CMD_MMC_RPMB
>  	bool "Enable support for RPMB in the mmc command"
>  	depends on SUPPORT_EMMC_RPMB
> diff --git a/cmd/mmc.c b/cmd/mmc.c
> index c6bd81cebbc..c29f44b7a18 100644
> --- a/cmd/mmc.c
> +++ b/cmd/mmc.c
> @@ -1110,6 +1110,93 @@ static int do_mmc_boot_wp(struct cmd_tbl *cmdtp, int flag,
>  	return CMD_RET_SUCCESS;
>  }
>  
> +#if CONFIG_IS_ENABLED(CMD_MMC_REG)
> +static int do_mmc_reg(struct cmd_tbl *cmdtp, int flag,
> +		      int argc, char *const argv[])
> +{
> +	ALLOC_CACHE_ALIGN_BUFFER(u8, ext_csd, MMC_MAX_BLOCK_LEN);
> +	struct mmc *mmc;
> +	int i, ret;
> +	u32 off;
> +
> +	if (argc < 3 || argc > 5)
> +		return CMD_RET_USAGE;
> +
> +	mmc = find_mmc_device(curr_device);
> +	if (!mmc) {
> +		printf("no mmc device at slot %x\n", curr_device);
> +		return CMD_RET_FAILURE;
> +	}
> +
> +	if (IS_SD(mmc)) {
> +		printf("SD registers are not supported\n");
> +		return CMD_RET_FAILURE;
> +	}
> +
> +	off = simple_strtoul(argv[3], NULL, 10);
> +	if (!strcmp(argv[2], "cid")) {
> +		if (off > 3)
> +			return CMD_RET_USAGE;
> +		printf("CID[%i]: 0x%08x\n", off, mmc->cid[off]);
> +		if (argv[4])
> +			env_set_hex(argv[4], mmc->cid[off]);
> +		return CMD_RET_SUCCESS;
> +	}
> +	if (!strcmp(argv[2], "csd")) {
> +		if (off > 3)
> +			return CMD_RET_USAGE;
> +		printf("CSD[%i]: 0x%08x\n", off, mmc->csd[off]);
> +		if (argv[4])
> +			env_set_hex(argv[4], mmc->csd[off]);
> +		return CMD_RET_SUCCESS;
> +	}
> +	if (!strcmp(argv[2], "dsr")) {
> +		printf("DSR: 0x%08x\n", mmc->dsr);
> +		if (argv[4])
> +			env_set_hex(argv[4], mmc->dsr);
> +		return CMD_RET_SUCCESS;
> +	}
> +	if (!strcmp(argv[2], "ocr")) {
> +		printf("OCR: 0x%08x\n", mmc->ocr);
> +		if (argv[4])
> +			env_set_hex(argv[4], mmc->ocr);
> +		return CMD_RET_SUCCESS;
> +	}
> +	if (!strcmp(argv[2], "rca")) {
> +		printf("RCA: 0x%08x\n", mmc->rca);
> +		if (argv[4])
> +			env_set_hex(argv[4], mmc->rca);
> +		return CMD_RET_SUCCESS;
> +	}
> +	if (!strcmp(argv[2], "extcsd") &&
> +	    mmc->version >= MMC_VERSION_4_41) {
> +		ret = mmc_send_ext_csd(mmc, ext_csd);
> +		if (ret)
> +			return ret;
> +		if (!strcmp(argv[3], "all")) {
> +			/* Dump the entire register */
> +			printf("EXT_CSD:");
> +			for (i = 0; i < MMC_MAX_BLOCK_LEN; i++) {
> +				if (!(i % 10))
> +					printf("\n%03i: ", i);
> +				printf(" %02x", ext_csd[i]);
> +			}
> +			printf("\n");
> +			return CMD_RET_SUCCESS;
> +		}
> +		off = simple_strtoul(argv[3], NULL, 10);
> +		if (off > 512)
> +			return CMD_RET_USAGE;
> +		printf("EXT_CSD[%i]: 0x%02x\n", off, ext_csd[off]);
> +		if (argv[4])
> +			env_set_hex(argv[4], ext_csd[off]);
> +		return CMD_RET_SUCCESS;
> +	}
> +
> +	return CMD_RET_FAILURE;
> +}
> +#endif
> +
>  static struct cmd_tbl cmd_mmc[] = {
>  	U_BOOT_CMD_MKENT(info, 1, 0, do_mmcinfo, "", ""),
>  	U_BOOT_CMD_MKENT(read, 4, 1, do_mmc_read, "", ""),
> @@ -1142,6 +1229,9 @@ static struct cmd_tbl cmd_mmc[] = {
>  	U_BOOT_CMD_MKENT(bkops-enable, 2, 0, do_mmc_bkops_enable, "", ""),
>  	U_BOOT_CMD_MKENT(bkops, 4, 0, do_mmc_bkops, "", ""),
>  #endif
> +#if CONFIG_IS_ENABLED(CMD_MMC_REG)
> +	U_BOOT_CMD_MKENT(reg, 5, 0, do_mmc_reg, "", ""),
> +#endif
>  };
>  
>  static int do_mmcops(struct cmd_tbl *cmdtp, int flag, int argc,
> @@ -1229,6 +1319,12 @@ U_BOOT_CMD(
>  	"   WARNING: This is a write-once setting.\n"
>  	"mmc bkops <dev> [auto|manual] [enable|disable]\n"
>  	" - configure background operations handshake on device\n"
> +#endif
> +#if CONFIG_IS_ENABLED(CMD_MMC_REG)
> +	"mmc reg read <reg> <offset> [env] - read card register <reg> offset <offset>\n"
> +	"                                    (optionally into [env] variable)\n"
> +	" - reg: cid/csd/dsr/ocr/rca/extcsd\n"
> +	" - offset: for cid/csd [0..3], for extcsd [0..511,all]\n"
>  #endif
>  	);
>  
> diff --git a/doc/usage/cmd/mmc.rst b/doc/usage/cmd/mmc.rst
> index 71a0303109c..c0924ba5769 100644
> --- a/doc/usage/cmd/mmc.rst
> +++ b/doc/usage/cmd/mmc.rst
> @@ -21,6 +21,7 @@ Synopsis
>      mmc bootpart-resize <dev> <dev part size MB> <RPMB part size MB>
>      mmc partconf <dev> [[varname] | [<boot_ack> <boot_partition> <partition_access>]]
>      mmc rst-function <dev> <value>
> +    mmc reg read <reg> <offset> [env]
>  
>  Description
>  -----------
> @@ -183,6 +184,31 @@ The 'mmc rst-function' command changes the RST_n_FUNCTION field.
>          0x3
>              Reserved
>  
> +The 'mmc reg read <reg> <offset> [env]' reads eMMC card register and
> +either print it to standard output, or store the value in environment
> +variable.
> +
> +<reg> with
> +optional offset <offset> into the register array, and print it to
> +standard output or store it into environment variable [env].
> +
> +    reg
> +        cid
> +            The Device IDentification (CID) register. Uses offset.
> +        csd
> +            The Device-Specific Data (CSD) register. Uses offset.
> +        dsr
> +            The driver stage register (DSR).
> +        ocr
> +            The operation conditions register (OCR).
> +        rca
> +            The relative Device address (RCA) register.
> +        extcsd
> +            The Extended CSD register. Uses offset.
> +    offset
> +        For 'cid'/'csd' 128 bit registers '[0..3]' in 32-bit increments. For 'extcsd' 512 bit register '[0..512,all]' in 8-bit increments, or 'all' to read the entire register.
> +    env
> +        Optional environment variable into which 32-bit value read from register should be stored.
>  
>  Examples
>  --------



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