CMD_CFG_LENGTH_MASK
mmc->max_blk_count = CMD_CFG_LENGTH_MASK;
desc[i].cmd_cfg |= FIELD_PREP(CMD_CFG_LENGTH_MASK, len);
cmd_cfg |= FIELD_PREP(CMD_CFG_LENGTH_MASK,
cmd_cfg |= FIELD_PREP(CMD_CFG_LENGTH_MASK, data->blksz);