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

[Tomas Melin]

Hi,

On 11/16/2016 02:05 PM, Jaehoon Chung wrote:
> 
> Why needs to set bkops on bootloader? Is there special reason?
> And Linux kernel has already discussed about this.
> 
It is beneficial to be able to do all required eMMC settings without being dependent on Linux booting.
It saves time in production to do initial eMMC setup directly from bootloader.

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

U-Boot already provides One-time programmable commands such as hwpartition and rst-function.
This adds to that same palette of commands that are needed when properly configuring an eMMC device. 

One possible option going forward could be putting all eMMC-configure related commands behind a common CONFIG_ option.

BR,
Tomas


> 
>>
>> 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
>>
>>