[PATCH master] ARM: omap: add two smaller MLO defconfigs for AM335x

[Sohaib Mohamed]

Hi,

On Sun, Dec 01, 2024 at 10:29:59PM +0100, Ahmad Fatoum wrote:
> The Beaglebone Black remains a popular board and it's not a good look to
> have it not compile by default due to barebox getting too big.
>
> As we keep running into size issues with the MLO defconfig, let's accept
> that we die bite off more than we could chew and split off the defconfigs
> into one for SD/MMC and another for NOR/NAND and document that users
> should prefer those instead.
>
> Reported-by: Sohaib Mohamed <sohaib.amhmd at gmail.com>
> Signed-off-by: Ahmad Fatoum <a.fatoum at pengutronix.de>
> ---
>  Documentation/boards/am335x.rst    | 28 +++++++++++++++++++++++++---
>  arch/arm/Makefile                  |  6 ++++++
>  common/boards/configs/nomci.config |  1 +
>  common/boards/configs/nomtd.config |  1 +
>  4 files changed, 33 insertions(+), 3 deletions(-)
>  create mode 100644 common/boards/configs/nomci.config
>  create mode 100644 common/boards/configs/nomtd.config
>
> diff --git a/Documentation/boards/am335x.rst b/Documentation/boards/am335x.rst
> index f54611428bb3..ec7322a0acdf 100644
> --- a/Documentation/boards/am335x.rst
> +++ b/Documentation/boards/am335x.rst
> @@ -8,9 +8,15 @@ loader from the same medium.
>  Building barebox
>  ----------------
>
> -The TI AM335x boards in barebox are covered by the ``am335x_mlo_defconfig``
> -for the MLO and ``omap_defconfig`` for the regular barebox image. The
> -resulting images will be placed under ``images/``:
> +Booting with barebox on the TI AM335x is a two-stage process and unlike
> +more recently added SoCs, requires building barebox twice, each time
> +with a different defconfig:
> +
> +* ``omap_defconfig`` for the regular (second-stage) barebox image
> +* For the MLO first-stage, either ``am335x_mlo_sdmmc_defconfig`` for
> +  SD/eMMC or ``am335x_mlo_rawflash_defconfig`` for raw NOR/NAND.
> +
> +The resulting images will be placed under ``images/``:
>
>  ::
>
> @@ -30,6 +36,22 @@ resulting images will be placed under ``images/``:
>
>  Some boards come in different variants, make sure to pick the correct one.
>
> +Size Constraints
> +^^^^^^^^^^^^^^^^
> +
> +As the MLO needs to setup DRAM first, it must fit into the 109KiB
> +of available on-Chip SRAM. Depending on the boards, drivers and general
> +features enabled by your config, barebox may exceed this size resulting
> +in an error message during build, e.g.::
> +
> +  images/start_am33xx_myirtech_sram.pblb size 111800 > maximum size 111616
> +
> +If you run into this issue, consider disabling some unneeded config options
> +for the MLO via ``make menuconfig`` and try again.
> +The ``am335x_mlo_sdmmc_defconfig`` and ``am335x_mlo_rawflash_defconfig``
> +defconfigs do just that by disabling ``CONFIG_MTD`` and ``CONFIG_MCI``,
> +respectively.
> +
>  Starting and updating barebox
>  -----------------------------
>
> diff --git a/arch/arm/Makefile b/arch/arm/Makefile
> index 6785432c52ca..7138f638651e 100644
> --- a/arch/arm/Makefile
> +++ b/arch/arm/Makefile
> @@ -2,6 +2,12 @@
>
>  KBUILD_DEFCONFIG := multi_v8_defconfig
>
> +generated_configs += $(patsubst %, %_defconfig, sdmmc rawflash)
> +am335x_mlo_sdmmc_defconfig:
> +	$(call merge_into_defconfig,am335x_mlo_defconfig,nomtd)
> +am335x_mlo_rawflash_defconfig:
> +	$(call merge_into_defconfig,am335x_mlo_defconfig,nomci)
> +
>  KBUILD_CPPFLAGS	+= -D__ARM__ -fno-strict-aliasing
>  # Explicitly specifiy 32-bit ARM ISA since toolchain default can be -mthumb:
>  ifeq ($(CONFIG_CPU_64),y)
> diff --git a/common/boards/configs/nomci.config b/common/boards/configs/nomci.config
> new file mode 100644
> index 000000000000..f541645cccfc
> --- /dev/null
> +++ b/common/boards/configs/nomci.config
> @@ -0,0 +1 @@
> +# CONFIG_MCI is not set
> diff --git a/common/boards/configs/nomtd.config b/common/boards/configs/nomtd.config
> new file mode 100644
> index 000000000000..f29845573ae6
> --- /dev/null
> +++ b/common/boards/configs/nomtd.config
> @@ -0,0 +1 @@
> +# CONFIG_MTD is not set

Is it possible to remove also CONFIG_MACH_MYIRTECH_X335X by default, I
still get this error:

  OBJCOPYB images/start_am33xx_myirtech_sram.pblb
  CHKFILESIZE images/start_am33xx_myirtech_sram.pblb
  OBJCOPYB images/start_am33xx_phytec_phycore_r2_sram.pblb
images/start_am33xx_myirtech_sram.pblb size 111856 > maximum size 111616
make[1]: *** [/home/smalinux/repos/bbb/barebox_standalone/barebox/images/Makefile:82: images/start_am33xx_myirtech_sram.pblb] Error 1
make[1]: *** Deleting file 'images/start_am33xx_myirtech_sram.pblb'
make[1]: *** Waiting for unfinished jobs....
  CHKFILESIZE images/start_am33xx_phytec_phycore_r2_sram.pblb
make: *** [Makefile:736: images] Error 2



> --
> 2.39.5
>