[PATCH] cmd: mmc: modify partconf to be used in script

[Jaehoon Chung]

On 12/14/20 11:45 PM, gr embeter wrote:
> Hi Jaehoon,
> thanks for replying.
> 
> On Mon, Dec 14, 2020 at 10:58 AM Jaehoon Chung <jh80.chung at samsung.com> wrote:
>>
>> Hi,
>>
>> On 12/12/20 4:46 PM, grygorii tertychnyi wrote:
>>> To implement dual-boot strategy we need to know what is the current
>>> boot partition for U-Boot. It can be easily identified by looking at
>>> the PARTITION_CONFIG value shown by "mmc partconf dev", but I didn't
>>> find any way to use it in the boot script.
>>>
>>> Hence, modify it, so that "mmc partboot dev part_num" command returns
>>> true if "part_num" is the current boot partition, otherwise it returns
>>> false.
>>
>> Sorry. I don't understand what you want.
> 
> Here is what I meant.
> We have two boot partitions on MMC: boot0 and boot1.
> And two kernels on MMC: "kernel-a" and "kernel-b".
> 
> I want to have a way to determine the current boot partition to
> implement the algorithm in the boot script:
> if (boot0 == currect_boot_partition())
>     boot("kernel-a")
> if (boot1 == currect_boot_partition())
>     boot("kernel-b")

According to my understanding, 
there are two kernels somewhere and you want to choose kernel according to boot partition, right?

Is there u-boot into boot partition? AFAIK, maybe there is some bl images, not u-boot.
Does it impossible to implement something in bl image?

> 
> With this patch it is possible to write:
> 
> if mmc partconf ${mmcdev} 1; then
>     echo "::::: booted from boot0"
>     ...
> fi
> if mmc partconf ${mmcdev} 2; then
>     echo "::::: booted from boot1"
>     ...
> fi
> 
>> And if you want to change something about mmc partconf, then you need to update the Usage.
>> There is no usage about yours.
>>
>> And i don't want to add its. It's too dangerous because of possible to set to wrong boot partition.
> 
> I will rework it and introduce a new mmc command for this specific action.
> 

If you need to add this behavior, adding new command is better than modifying partconf.

Best Regards,
Jaehoon Chung

> 
> 
>> Best Regards,
>> Jaehoon Chung
>>
>>>
>>> Signed-off-by: Grygorii Tertychnyi <grygorii.tertychnyi at leica-geosystems.com>
>>> ---
>>>  cmd/mmc.c | 23 ++++++++++++++++++++++-
>>>  1 file changed, 22 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/cmd/mmc.c b/cmd/mmc.c
>>> index 1529a3e05ddd..c8db008bc90d 100644
>>> --- a/cmd/mmc.c
>>> +++ b/cmd/mmc.c
>>> @@ -792,6 +792,23 @@ static int mmc_partconf_print(struct mmc *mmc)
>>>       return CMD_RET_SUCCESS;
>>>  }
>>>
>>> +static int mmc_partnum_cmp(struct mmc *mmc, u8 part_num)
>>> +{
>>> +     u8 part;
>>> +
>>> +     if (mmc->part_config == MMCPART_NOAVAILABLE) {
>>> +             printf("No part_config info for ver. 0x%x\n", mmc->version);
>>> +             return CMD_RET_FAILURE;
>>> +     }
>>> +
>>> +     part = EXT_CSD_EXTRACT_BOOT_PART(mmc->part_config);
>>> +
>>> +     if (part == part_num)
>>> +             return CMD_RET_SUCCESS;
>>> +     else
>>> +             return CMD_RET_FAILURE;
>>> +}
>>> +
>>>  static int do_mmc_partconf(struct cmd_tbl *cmdtp, int flag,
>>>                          int argc, char *const argv[])
>>>  {
>>> @@ -799,7 +816,7 @@ static int do_mmc_partconf(struct cmd_tbl *cmdtp, int flag,
>>>       struct mmc *mmc;
>>>       u8 ack, part_num, access;
>>>
>>> -     if (argc != 2 && argc != 5)
>>> +     if (argc != 2 && argc != 3 && argc != 5)
>>>               return CMD_RET_USAGE;
>>>
>>>       dev = simple_strtoul(argv[1], NULL, 10);
>>> @@ -815,6 +832,10 @@ static int do_mmc_partconf(struct cmd_tbl *cmdtp, int flag,
>>>
>>>       if (argc == 2)
>>>               return mmc_partconf_print(mmc);
>>> +     if (argc == 3) {
>>> +             part_num = simple_strtoul(argv[2], NULL, 10);
>>> +             return mmc_partnum_cmp(mmc, part_num);
>>> +     }
>>>
>>>       ack = simple_strtoul(argv[2], NULL, 10);
>>>       part_num = simple_strtoul(argv[3], NULL, 10);
>>>
>>
>