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

[Ahmad Fatoum <a.fatoum@pengutronix.de>]

On 02.12.24 09:03, Sascha Hauer wrote:
> On Sun, Dec 01, 2024 at 11:53:59PM +0100, Sohaib Mohamed wrote:
>> 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@gmail.com>
>>> Signed-off-by: Ahmad Fatoum <a.fatoum@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:
> 
> With Ahamds patch you have to use either am335x_mlo_sdmmc_defconfig
> or am335x_mlo_rawflash_defconfig depending on where you are booting
> from. Did you use one of them? Even with Ahmads patch the old
> am335x_mlo_defconfig is still there and still leads to an image
> exceeding the size limit.

In addition to what Sascha said, I shaved off 400~ more bytes in my v2.
This should give us enough breathing room for the next release.

For the release after that, I intend to rework the size check, so it doesn't
fail the build, but just produces a warning at the end of it, e.g.:

  images built:
  barebox-nxp-imx8mm-evk.img
  barebox-prt-prt8mm.img
  ** barebox-tqma93xx.img skipped due to missing firmware **
  ** barebox-karo-qsxp-ml81.img skipped due to size 111856 > maximum size 111616 **

Cheers,
Ahmad

> 
> Sascha
> 
>>
>>   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
>>>
>>
>>
> 


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