[PATCH 3/4] cmd: mmc: display write protect state of boot partition

[Jaehoon Chung <jh80.chung@samsung.com>]

On 4/1/20 3:05 PM, Heinrich Schuchardt wrote:
> On 4/1/20 5:04 AM, Jaehoon Chung wrote:
>> Hi,
>>
>> On 3/30/20 2:24 PM, Heinrich Schuchardt wrote:
>>> Boot partitions of eMMC devices can be power on or permanently write
>>> protected. Let the 'mmc info' command display the protection state.
>>>
>>> Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
>>> ---
>>>  cmd/mmc.c | 24 ++++++++++++++++++++++++
>>>  1 file changed, 24 insertions(+)
>>>
>>> diff --git a/cmd/mmc.c b/cmd/mmc.c
>>> index 6f3cb85cc0..d62c85e439 100644
>>> --- a/cmd/mmc.c
>>> +++ b/cmd/mmc.c
>>> @@ -54,6 +54,8 @@ static void print_mmcinfo(struct mmc *mmc)
>>>  	if (!IS_SD(mmc) && mmc->version >= MMC_VERSION_4_41) {
>>>  		bool has_enh = (mmc->part_support & ENHNCD_SUPPORT) != 0;
>>>  		bool usr_enh = has_enh && (mmc->part_attr & EXT_CSD_ENH_USR);
>>> +		u8 wp, ext_csd[MMC_MAX_BLOCK_LEN];
>>> +		int ret;
>>>
>>>  #if CONFIG_IS_ENABLED(MMC_HW_PARTITIONING)
>>>  		puts("HC WP Group Size: ");
>>> @@ -90,6 +92,28 @@ static void print_mmcinfo(struct mmc *mmc)
>>>  					putc('\n');
>>>  			}
>>>  		}
>>> +		ret = mmc_send_ext_csd(mmc, ext_csd);
>>> +		if (ret)
>>> +			return;
>>
>> Is it really needed to call mmc_send_ext_csd() at here.
>> ext_csd register value was already read somewhere.
> 
> struct mmc does not contain the extended CSD. Performancewise it does
> not make sense to carry a copy which would have to be updated after each
> command that could potentially update it like SWITCH.

Why doesn't make sense to carry a copy? Its value can be updated whenever it's changed.
If someone want to set "write protect", then it has to follow sequence.
read ext_csd -> check value -> send_switch command 
Then it's possible to keep its value..

And some values are one-time programmable. it's not efficient about sending command to read again.

Best Regards,
Jaehoon Chung

> 
> The call to mmc_send_ext_csd() does not lead to any visible performance
> issue here.
> 
> Best regards
> 
> Heinrich
> 
>>
>> Best Regards,
>> Jaehoon Chung
>>
>>> +		wp = ext_csd[EXT_CSD_BOOT_WP_STATUS];
>>> +		for (i = 0; i < 2; ++i) {
>>> +			printf("Boot area %d is ", i);
>>> +			switch (wp & 3) {
>>> +			case 0:
>>> +				printf("not write protected\n");
>>> +				break;
>>> +			case 1:
>>> +				printf("power on protected\n");
>>> +				break;
>>> +			case 2:
>>> +				printf("permanently protected\n");
>>> +				break;
>>> +			default:
>>> +				printf("in reserved protection state\n");
>>> +				break;
>>> +			}
>>> +			wp >>= 2;
>>> +		}
>>>  	}
>>>  }
>>>  static struct mmc *init_mmc_device(int dev, bool force_init)
>>> --
>>> 2.25.1
>>>
>>>
>>>
>>
> 
> 
>