[PATCH V2 2/5] fdtdec: Add weak function to patch U-Boot DT right after fdtdec_setup()

[Marek Vasut]

On 5/19/20 3:45 PM, Bin Meng wrote:
> On Tue, May 19, 2020 at 9:43 PM Marek Vasut <marek.vasut at gmail.com> wrote:
>>
>> On 5/19/20 3:33 PM, Bin Meng wrote:
>>> On Tue, May 19, 2020 at 8:40 PM Marek Vasut <marek.vasut at gmail.com> wrote:
>>>>
>>>> Add weak function which is called right after fdtdec_setup() configured
>>>> the U-Boot DT. This permits board-specific adjustments to the U-Boot DT
>>>> before U-Boot starts parsing the DT. This could be used e.g. to patch in
>>>> various custom nodes or merge in DT fragments from prior-stage firmware.
>>>>
>>>> Signed-off-by: Marek Vasut <marek.vasut+renesas at gmail.com>
>>>> Cc: Nobuhiro Iwamatsu <iwamatsu at nigauri.org>
>>>> Cc: Simon Glass <sjg at chromium.org>
>>>> Cc: Tom Rini <trini at konsulko.com>
>>>> ---
>>>> V2: Add the function to fdtdec.h
>>>> ---
>>>>  include/fdtdec.h |  5 +++++
>>>>  lib/fdtdec.c     | 11 ++++++++++-
>>>>  2 files changed, 15 insertions(+), 1 deletion(-)
>>>>
>>>> diff --git a/include/fdtdec.h b/include/fdtdec.h
>>>> index 166f29c55b..abd6d42671 100644
>>>> --- a/include/fdtdec.h
>>>> +++ b/include/fdtdec.h
>>>> @@ -1155,6 +1155,11 @@ int fdtdec_set_carveout(void *blob, const char *node, const char *prop_name,
>>>>   */
>>>>  int fdtdec_setup(void);
>>>>
>>>> +/**
>>>> + * Perform board-specific early DT adjustments
>>>> + */
>>>> +int fdtdec_board_setup(const void *fdt_blob);
>>>> +
>>>>  #if CONFIG_IS_ENABLED(MULTI_DTB_FIT)
>>>>  /**
>>>>   * fdtdec_resetup()  - Set up the device tree again
>>>> diff --git a/lib/fdtdec.c b/lib/fdtdec.c
>>>> index 0a3b860782..f366dcedb8 100644
>>>> --- a/lib/fdtdec.c
>>>> +++ b/lib/fdtdec.c
>>>> @@ -1472,8 +1472,14 @@ int fdtdec_set_carveout(void *blob, const char *node, const char *prop_name,
>>>>         return 0;
>>>>  }
>>>>
>>>> +__weak int fdtdec_board_setup(const void *fdt_blob)
>>>> +{
>>>> +       return 0;
>>>> +}
>>>> +
>>>>  int fdtdec_setup(void)
>>>>  {
>>>> +       int ret;
>>>>  #if CONFIG_IS_ENABLED(OF_CONTROL)
>>>>  # if CONFIG_IS_ENABLED(MULTI_DTB_FIT)
>>>>         void *fdt_blob;
>>>> @@ -1526,7 +1532,10 @@ int fdtdec_setup(void)
>>>>  # endif
>>>>  #endif
>>>>
>>>> -       return fdtdec_prepare_fdt();
>>>> +       ret = fdtdec_prepare_fdt();
>>>> +       if (!ret)
>>>> +               ret = fdtdec_board_setup(gd->fdt_blob);
>>>> +       return ret;
>>>>  }
>>>
>>> There is already a CONFIG_OF_BOARD_FIXUP (fix_fdt) in board_f.c
>>>
>>> Should we consider moving that into fdtdec_setup()?
>>
>> This one is run much earlier and this is the only fitting location.
> 
> I know. I was asking should we move the existing one into
> fdtdec_setup(). The basically do the same.

Sure, send a patch, but let's do that after the release to avoid
breakage. I suspect there are various cornercases just waiting to be
triggered.

-- 
Best regards,
Marek Vasut