[U-Boot] mmc: add bkops-enable command

[Jaehoon Chung]

Hi,

On 11/16/2016 06:59 PM, tomas.melin at vaisala.com wrote:
> Add new command for enabling the background operations
> handshake functionality (BKOPS_EN, EXT_CSD byte [163])
> on eMMC devices.
> 
> This is an optional feature of eMMCs, the setting is write-once.

Why needs to set bkops on bootloader? Is there special reason?
And Linux kernel has already discussed about this.

I don't want to provide this command on u-boot side.
Don't handle Onetime programmable register on u-boot. So NACK.

Best Regards,
Jaehoon Chung


> 
> Signed-off-by: Tomas Melin <tomas.melin at vaisala.com>
> ---
>  cmd/mmc.c         | 26 ++++++++++++++++++++++++++
>  drivers/mmc/mmc.c | 30 ++++++++++++++++++++++++++++++
>  include/mmc.h     |  4 ++++
>  3 files changed, 60 insertions(+)
> 
> diff --git a/cmd/mmc.c b/cmd/mmc.c
> index b2761e9..3ae9682 100644
> --- a/cmd/mmc.c
> +++ b/cmd/mmc.c
> @@ -729,6 +729,29 @@ static int do_mmc_setdsr(cmd_tbl_t *cmdtp, int flag,
>  	return ret;
>  }
>  
> +static int do_mmc_bkops_enable(cmd_tbl_t *cmdtp, int flag,
> +				   int argc, char * const argv[])
> +{
> +	int dev;
> +	struct mmc *mmc;
> +
> +	if (argc != 2)
> +		return CMD_RET_USAGE;
> +
> +	dev = simple_strtoul(argv[1], NULL, 10);
> +
> +	mmc = init_mmc_device(dev, false);
> +	if (!mmc)
> +		return CMD_RET_FAILURE;
> +
> +	if (IS_SD(mmc)) {
> +		puts("BKOPS_EN only exists on eMMC\n");
> +		return CMD_RET_FAILURE;
> +	}
> +
> +	return mmc_set_bkops_enable(mmc);
> +}
> +
>  static cmd_tbl_t cmd_mmc[] = {
>  	U_BOOT_CMD_MKENT(info, 1, 0, do_mmcinfo, "", ""),
>  	U_BOOT_CMD_MKENT(read, 4, 1, do_mmc_read, "", ""),
> @@ -749,6 +772,7 @@ static cmd_tbl_t cmd_mmc[] = {
>  	U_BOOT_CMD_MKENT(rpmb, CONFIG_SYS_MAXARGS, 1, do_mmcrpmb, "", ""),
>  #endif
>  	U_BOOT_CMD_MKENT(setdsr, 2, 0, do_mmc_setdsr, "", ""),
> +	U_BOOT_CMD_MKENT(bkops-enable, 2, 0, do_mmc_bkops_enable, "", ""),
>  };
>  
>  static int do_mmcops(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
> @@ -813,6 +837,8 @@ U_BOOT_CMD(
>  	"mmc rpmb counter - read the value of the write counter\n"
>  #endif
>  	"mmc setdsr <value> - set DSR register value\n"
> +	"mmc bkops-enable <dev> - enable background operations handshake on device\n"
> +	"   WARNING: This is a write-once setting.\n"
>  	);
>  
>  /* Old command kept for compatibility. Same as 'mmc info' */
> diff --git a/drivers/mmc/mmc.c b/drivers/mmc/mmc.c
> index 0cec02c..d6f40cc 100644
> --- a/drivers/mmc/mmc.c
> +++ b/drivers/mmc/mmc.c
> @@ -1810,3 +1810,33 @@ int mmc_initialize(bd_t *bis)
>  	mmc_do_preinit();
>  	return 0;
>  }
> +
> +int mmc_set_bkops_enable(struct mmc *mmc)
> +{
> +	int err;
> +	ALLOC_CACHE_ALIGN_BUFFER(u8, ext_csd, MMC_MAX_BLOCK_LEN);
> +
> +	err = mmc_send_ext_csd(mmc, ext_csd);
> +	if (err) {
> +		puts("Could not get ext_csd register values\n");
> +		return err;
> +	}
> +
> +	if (!(ext_csd[EXT_CSD_BKOPS_SUPPORT] & 0x1)) {
> +		puts("Background operations not supported on device\n");
> +		return -EMEDIUMTYPE;
> +	}
> +
> +	if (ext_csd[EXT_CSD_BKOPS_EN] & 0x1) {
> +		puts("Background operations already enabled\n");
> +		return 0;
> +	}
> +
> +	err = mmc_switch(mmc, EXT_CSD_CMD_SET_NORMAL, EXT_CSD_BKOPS_EN, 1);
> +	if (err) {
> +		puts("Failed to enable background operations\n");
> +		return err;
> +	}
> +
> +	return 0;
> +}
> diff --git a/include/mmc.h b/include/mmc.h
> index 5ef37d3..0772d53 100644
> --- a/include/mmc.h
> +++ b/include/mmc.h
> @@ -175,6 +175,7 @@
>  #define EXT_CSD_MAX_ENH_SIZE_MULT	157	/* R */
>  #define EXT_CSD_PARTITIONING_SUPPORT	160	/* RO */
>  #define EXT_CSD_RST_N_FUNCTION		162	/* R/W */
> +#define EXT_CSD_BKOPS_EN		163	/* R/W */
>  #define EXT_CSD_WR_REL_PARAM		166	/* R */
>  #define EXT_CSD_WR_REL_SET		167	/* R/W */
>  #define EXT_CSD_RPMB_MULT		168	/* RO */
> @@ -189,6 +190,7 @@
>  #define EXT_CSD_HC_WP_GRP_SIZE		221	/* RO */
>  #define EXT_CSD_HC_ERASE_GRP_SIZE	224	/* RO */
>  #define EXT_CSD_BOOT_MULT		226	/* RO */
> +#define EXT_CSD_BKOPS_SUPPORT		502	/* RO */
>  
>  /*
>   * EXT_CSD field definitions
> @@ -541,6 +543,8 @@ int mmc_rpmb_read(struct mmc *mmc, void *addr, unsigned short blk,
>  		  unsigned short cnt, unsigned char *key);
>  int mmc_rpmb_write(struct mmc *mmc, void *addr, unsigned short blk,
>  		   unsigned short cnt, unsigned char *key);
> +int mmc_set_bkops_enable(struct mmc *mmc);
> +
>  /**
>   * Start device initialization and return immediately; it does not block on
>   * polling OCR (operation condition register) status.  Then you should call
> 
>