[U-Boot] [PATCH v2 2/2] fastboot: Fix slot names reported by getvar

[Lukasz Majewski <lukma@denx.de>]

Hi Sam,

> Fastboot tool recently underwent changes w.r.t. A/B slot format:
>   1. In commit [1] the new slot format was introduced, according to
> new A/B specification [2]. New slot format is "a", and old format "_a"
>      is now considered legacy.
>   2. In commit [3] the legacy format "_a" was fixed and fastboot tool
>      should support both "a" and "_a" slot formats now.
>   3. Finally, commit [4] drops the legacy slot format ("_a")
> completely. That makes the latest fastboot tool incompatible with
> "_a" format.
> 
> Last change leads to next error, when running "fastboot flash" with
> current U-Boot:
> 
>     $ fastboot flash boot boot.img
>     Sending 'boot__a' (11301 KB)    OKAY [  0.451s]
>     Writing 'boot__a'               FAILED (remote: 'cannot find
> partition') fastboot: error: Command failed
> 
> To overcome this issue we should report slot names in "a" format
> instead of "_a". Of course, this change breaks U-Boot compatibility
> with older fastboot tools, but that shouldn't be a problem as A/B is
> not implemented in U-Boot yet, and there are not users for slotted
> partitions out there anyway. This fact can be checked like this:
> 
>     $ grep -Ir \b'boot_a\b' *
> 
> Let's use new slot format in order to fix "fastboot flash" with
> slotted partitions and to be in sync with AOSP master.
> 
> With this patch, U-Boot depends on most recent fastboot tool (patch
> [1] or later), for working with slotted partitions.

Is there any "version" number scheme for the fastboot protocol
specification?

I do remember that in the past there were some mismatches for some
"fastboot" specification depending on vendor. Now it turns out that
there is a problem between AOSP versions ...

(My point is that for example even lthor had version number for
specification update. Is something similar for fastboot?). 

> 
> [1]
> https://android.googlesource.com/platform/system/core/+/8091947847d5e5130b09d2ac0a4bdc900f3b77c5
> [2]
> https://source.android.com/devices/tech/ota/ab/ab_implement#partitions
> [3]
> https://android.googlesource.com/platform/system/core/+/04396f62da6150b94e02d50e5302fd980048833d
> [4]
> https://android.googlesource.com/platform/system/core/+/42b18a518bac85c3eea14206f6cbafbd1e98a31f
> 
> Signed-off-by: Sam Protsenko <semen.protsenko@linaro.org>
> ---
> Changes in v2:
>   - don't change slot format in "slot-suffixes" variable (it's now
>     dropped in [PATCH 1/2])
>   - improve commit message
> 
>  drivers/fastboot/fb_getvar.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/fastboot/fb_getvar.c
> b/drivers/fastboot/fb_getvar.c index f89c7f62e6..9ee5054485 100644
> --- a/drivers/fastboot/fb_getvar.c
> +++ b/drivers/fastboot/fb_getvar.c
> @@ -174,8 +174,8 @@ static void getvar_platform(char *var_parameter,
> char *response) 
>  static void getvar_current_slot(char *var_parameter, char *response)
>  {
> -	/* A/B not implemented, for now always return _a */
> -	fastboot_okay("_a", response);
> +	/* A/B not implemented, for now always return "a" */
> +	fastboot_okay("a", response);
>  }
>  
>  #if CONFIG_IS_ENABLED(FASTBOOT_FLASH)




Best regards,

Lukasz Majewski

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