Re: [PATCH v3 2/6] treewide: bcb: move ab_select command to bcb subcommands

Dmitry Rokosov
2024-10-14T20:38:32Z

Hello Mattijs,

On Sat, Oct 12, 2024 at 10:49:08AM +0200, Mattijs Korpershoek wrote:
> Hi Dmitry,
>
> On ven., oct. 11, 2024 at 21:00, Dmitry Rokosov <ddrokosov@salutedevices.com> wrote:
>
> > On Fri, Oct 11, 2024 at 04:20:39PM +0200, Mattijs Korpershoek wrote:
> >> On ven., oct. 11, 2024 at 15:30, "Mattijs Korpershoek via groups.io" <mkorpershoek=baylibre.com@groups.io> wrote:
> >>
> >> > Hi Dmitry,
> >> >
> >> > Thank you for the patch.
> >> >
> >> > On mar., oct. 08, 2024 at 23:18, Dmitry Rokosov <ddrokosov@salutedevices.com> wrote:
> >> >
> >> >> To enhance code organization, it is beneficial to consolidate all A/B
> >> >> BCB management routines into a single super-command.
> >> >> The 'bcb' command is an excellent candidate for this purpose.
> >> >>
> >> >> This patch integrates the separate 'ab_select' command into the 'bcb'
> >> >> group as the 'ab_select' subcommand, maintaining the same parameter list
> >> >> for consistency.
> >> >>
> >> >> Signed-off-by: Dmitry Rokosov <ddrokosov@salutedevices.com>
> >> >> ---
> >> >> MAINTAINERS | 1 -
> >> >> cmd/Kconfig | 15 +------
> >> >> cmd/Makefile | 1 -
> >> >> cmd/ab_select.c | 66 -------------------------------
> >> >> cmd/bcb.c | 63 +++++++++++++++++++++++++++++
> >> >> configs/am57xx_hs_evm_usb_defconfig | 1 -
> >> >> configs/khadas-vim3_android_ab_defconfig | 1 -
> >> >> configs/khadas-vim3l_android_ab_defconfig | 1 -
> >> >> configs/sandbox64_defconfig | 4 +-
> >> >> configs/sandbox_defconfig | 4 +-
> >> >> doc/android/ab.rst | 12 +++---
> >> >> include/configs/khadas-vim3_android.h | 2 +-
> >> >> include/configs/khadas-vim3l_android.h | 2 +-
> >> >> include/configs/meson64_android.h | 4 +-
> >> >> include/configs/ti_omap5_common.h | 4 +-
> >> >> test/py/tests/test_android/test_ab.py | 8 ++--
> >> >> 16 files changed, 85 insertions(+), 104 deletions(-)
> >> >>
> >> >> diff --git a/MAINTAINERS b/MAINTAINERS
> >> >> index 7aefda93d017f07d616f0f6d191129914fbeb484..668ccec9ae6df47192b1af668e3fdbeb1dfa15ea 100644
> >> >> --- a/MAINTAINERS
> >> >> +++ b/MAINTAINERS
> >> >> @@ -65,7 +65,6 @@ R: Sam Protsenko <semen.protsenko@linaro.org>
> >> >> S: Maintained
> >> >> T: git https://source.denx.de/u-boot/custodians/u-boot-dfu.git
> >> >> F: boot/android_ab.c
> >> >> -F: cmd/ab_select.c
> >> >> F: doc/android/ab.rst
> >> >> F: include/android_ab.h
> >> >> F: test/py/tests/test_android/test_ab.py
> >> >> diff --git a/cmd/Kconfig b/cmd/Kconfig
> >> >> index dd33266cec70a2b134b7244acae1b7f098b921e8..11e8d363dc9b137723a86a240412d82dd0dbccc5 100644
> >> >> --- a/cmd/Kconfig
> >> >> +++ b/cmd/Kconfig
> >> >> @@ -1067,6 +1067,7 @@ config CMD_ADC
> >> >> config CMD_BCB
> >> >> bool "bcb"
> >> >> depends on PARTITIONS
> >> >> + depends on ANDROID_AB
> >> >
> >> > When building with khadas-vim3_android_defconfig, we can see that CMD_BCB is no
> >> > longer part of that build:
> >> >
> >> > $ grep CMD_BCB .config
> >> > <empty>
> >> >
> >> > However, if we look at include/configs/meson64_android.h, we can see
> >> > that the "bcb" command is not only used for checking the _slot suffix.
> >> >
> >> > It's also used for checking the bootloader reason. For example, in
> >> > BOOTENV_DEV_FASTBOOT, we call:
> >> >
> >> > "if bcb test command = bootonce-bootloader; then " \
> >> >
> >> > Since CMD_BCB is no longer part of the .config (due to this dependency),
> >> > the boot script now shows errors:
> >> >
> >> > """
> >> > U-Boot 2024.10-00796-g969325278805 (Oct 11 2024 - 14:46:00 +0200) khadas-vim3
> >> >
> >> > Model: Khadas VIM3
> >> > SoC: Amlogic Meson G12B (A311D) Revision 29:b (10:2)
> >> > DRAM: 2 GiB (effective 3.8 GiB)
> >> > Core: 411 devices, 36 uclasses, devicetree: separate
> >> > MMC: mmc@ffe03000: 0, mmc@ffe05000: 1, mmc@ffe07000: 2
> >> > Loading Environment from MMC... fs uses incompatible features: 00020000, ignoring
> >> > Reading from MMC(2)... *** Warning - bad CRC, using default environment
> >> >
> >> > In: usbkbd,serial
> >> > Out: vidconsole,serial
> >> > Err: vidconsole,serial
> >> > Net: eth0: ethernet@ff3f0000
> >> >
> >> > Hit any key to stop autoboot: 0
> >> > Verify GPT: success!
> >> > Unknown command 'bcb' - try 'help'
> >> > Warning: BCB is corrupted or does not exist
> >> > dev: pinctrl@14
> >> > dev: pinctrl@40
> >> > gpio: pin 88 (gpio 88) value is 1
> >> > Unknown command 'bcb' - try 'help'
> >> > Warning: BCB is corrupted or does not exist
> >> > Loading Android boot partition...
> >> > switch to partitions #0, OK
> >> > mmc2(part 0) is current device
> >> > """
> >> >
> >> > I know we should not be using a boot script, nor non A/B configs but
> >> > it's a bummer that this series breaks an upstream
> >> > defconfig (khadas-vim3_android_defconfig)
> >> >
> >> > My recommendation:
> >> >
> >> > Make BCB_CMD_AB_SELECT implementation dependant on ANDROID_AB.
> >> > This way, users can use CMD_BCB with and without ANDROID_AB being enabled.
> >> >
> >> > We could do:
> >> > When ANDROID_AB=y, implement bcb ab_select subcommand
> >> > When ANDROID_AB=n, command is not accessible.
> >> >
> >> > I'll send you a diff shortly for this.
> >>
> >> Here is an illustration on how that would work:
> >>
> >> diff --git a/cmd/Kconfig b/cmd/Kconfig
> >> index 861c31e26408..e1a4a97b042d 100644
> >> --- a/cmd/Kconfig
> >> +++ b/cmd/Kconfig
> >> @@ -1055,7 +1055,6 @@ config CMD_ADC
> >> config CMD_BCB
> >> bool "bcb"
> >> depends on PARTITIONS
> >> - depends on ANDROID_AB
> >> help
> >> Read/modify/write the fields of Bootloader Control Block, usually
> >> stored on the flash "misc" partition with its structure defined in:
> >> diff --git a/cmd/bcb.c b/cmd/bcb.c
> >> index 4fd32186ae65..4fe634f14cc5 100644
> >> --- a/cmd/bcb.c
> >> +++ b/cmd/bcb.c
> >> @@ -438,6 +438,9 @@ static int do_bcb_ab_select(struct cmd_tbl *cmdtp, int flag, int argc,
> >> char slot[2];
> >> bool dec_tries = true;
> >>
> >> + if (!CONFIG_IS_ENABLED(AB_SELECT))
> >> + return CMD_RET_SUCCESS;
> >> +
> >> for (int i = 4; i < argc; i++) {
> >> if (!strcmp(argv[i], "--no-dec"))
> >> dec_tries = false;
> >> @@ -474,6 +477,9 @@ static int do_bcb_ab_dump(struct cmd_tbl *cmdtp, int flag, int argc,
> >> struct blk_desc *dev_desc;
> >> struct disk_partition part_info;
> >>
> >> + if (!CONFIG_IS_ENABLED(AB_SELECT))
> >> + return CMD_RET_SUCCESS;
> >> +
> >> if (part_get_info_by_dev_and_name_or_num(argv[1], argv[2],
> >> &dev_desc, &part_info,
> >> false) < 0) {
> >>
> >
> > We also need to include an #ifdef directive for the ab_select_slot()
> > function usage; otherwise, the code will not compile successfully.
>
> Are you sure? Per my understanding, it's possible that the compiler
> optimizes this out because CONFIG_IS_ENABLED(AB_SELECT)
> is known as build time.
>
> When I tried this diff with khadas-vim3_android_defconfig I did not see
> any build errors. I will try again early next week.
>

As I recall, the IS_ENABLED() mechanism serves as a runtime checker to
determine whether specific CONFIG_* options are enabled. Consequently,
all code paths under this mechanism are always compiled. I attempted to
disable CONFIG_ANDROID_AB for the sandbox_defconfig, but it resulted in
the expected linker error.

/tmp/ccAvYrKL.ltrans25.ltrans.o: In function `do_bcb_ab_select':
<artificial>:(.text+0x6d5d): undefined reference to `ab_select_slot'
collect2: error: ld returned 1 exit status
Makefile:1813: recipe for target 'u-boot' failed
make: *** [u-boot] Error 1

I have already prepared a new version using #ifdef directives. I will
send it shortly.

[...]

--
Thank you,
Dmitry