Hi Andrey, > Hi Lukasz, > > On Thu, Nov 9, 2017 at 2:28 PM, Lukasz Majewski > <l.majew...@majess.pl> wrote: > > On Thu, 9 Nov 2017 07:34:44 -0800 > > Andrey Yurovsky <yurov...@gmail.com> wrote: > > > >> On Thu, Nov 9, 2017 at 1:55 AM, Lukasz Majewski > >> <l.majew...@majess.pl> wrote: > >> > Hi Andrey, > >> > > >> >> Hi Otavio, > >> >> > >> >> On Wed, Nov 8, 2017 at 2:47 AM, Otavio Salvador > >> >> <otavio.salva...@ossystems.com.br> wrote: > >> >> > On Tue, Nov 7, 2017 at 10:43 PM, your name > >> >> > <yurov...@gmail.com> wrote: > >> >> >> From: Andrey Yurovsky <yurov...@gmail.com> > >> >> >> > >> >> >> It is useful to be able to retrieve a partition UUID or > >> >> >> number given the partition label, for instance some systems > >> >> >> use the partition label to indicate the purpose of the > >> >> >> partition (such as "rootfs0" being the 0th root file system > >> >> >> in an A/B image scheme). > >> >> >> > >> >> >> Add "gpt part-uuid" to retrieve the partition UUID for a > >> >> >> given label and "gpt part-num" to retrieve the partition > >> >> >> number for a given label along with some documentation. > >> >> >> > >> >> >> Signed-off-by: Andrey Yurovsky <yurov...@gmail.com> > >> >> > > >> >> > Why not use the 'part' cmd? it provides it. > >> >> > >> >> Sorry, I missed the part cmd, it doesn't seem to be documented > >> >> in doc/ and it's unclear what <dev> means there. > >> > > >> > If I may ask - Andrey, if you are now on this "topic" - would you > >> > dare to add some ./doc entry for 'part' command? > >> > >> Yes, I will do that. > > > > Thanks :-) > > On further investigation I am not sure that it's possible to extend > the part command to retrieve UUIDs by label because of the design of > the partition type drivers. Here is how I understand it to work: > 1. the "part" command uses part_get_info() and in turn gets a > partition driver and can call print() there (which is how EFI/GPT > disks are printed with "part list"). The right information (including > label) is printed but it's not tied to the caller in any way.
Maybe you can set some env variable with proper data? For example, please refer to ./cmd/part.c do_part_start() function. Example call from envs (include/configs/display5.h): "part start mmc ${mmcdev} ${kernel_part} lba_start; " \ > 2. "part uuid" blk_get_device_part_str() which in turn can get > information but referenced by partition number (and only partition > number, due to how part_get_info() works). There's nothing at the > 'part' layer tying a label to a number though so one would already > need to know the number, which is the problem I'm trying to solve. > > This layering keeps partitioning generalized and decoupled from the > underlying partition "driver" but there's no concept of a label in the > "driver" API. I'm not sure if it's reasonable to extend it since > part_get_info() and similar really don't have a way to map labels at > this layer so perhaps extending the GPT-specific command is the only > reasonable approach? > _______________________________________________ > U-Boot mailing list > U-Boot@lists.denx.de > https://lists.denx.de/listinfo/u-boot -- Best regards, Ćukasz Majewski
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