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Date:   Thu, 21 Feb 2019 18:50:43 -0300
From:   Paul Cercueil <paul@crapouillou.net>
Subject: Re: [PATCH] MIPS: ingenic: Add support for appended devicetree
To:     Jonas Gorski <jonas.gorski@gmail.com>
Cc:     Ralf Baechle <ralf@linux-mips.org>,
        Paul Burton <paul.burton@mips.com>,
        James Hogan <jhogan@kernel.org>, linux-mips@vger.kernel.org,
        linux-kernel@vger.kernel.org
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Hi Jonas,

On Thu, 21 Feb 2019 at 21:39, Jonas Gorski <jonas.gorski@gmail.com> 
wrote:
> On Thu, 21 Feb 2019 at 21:39, Paul Cercueil <paul@crapouillou.net> 
> wrote:
>> 
>>  Add support for booting the kernel from an externally-appended
>>  devicetree, if no devicetree was built-in.
>> 
>>  Signed-off-by: Paul Cercueil <paul@crapouillou.net>
>>  ---
>>   arch/mips/Kconfig        |  2 +-
>>   arch/mips/jz4740/setup.c | 14 +++++++++++---
>>   2 files changed, 12 insertions(+), 4 deletions(-)
>> 
>>  diff --git a/arch/mips/Kconfig b/arch/mips/Kconfig
>>  index a84c24d894aa..8b7ea9062198 100644
>>  --- a/arch/mips/Kconfig
>>  +++ b/arch/mips/Kconfig
>>  @@ -391,7 +391,7 @@ config MACH_INGENIC
>>          select GPIOLIB
>>          select COMMON_CLK
>>          select GENERIC_IRQ_CHIP
>>  -       select BUILTIN_DTB
>>  +       select BUILTIN_DTB if MIPS_NO_APPENDED_DTB
>>          select USE_OF
>>          select LIBFDT
>> 
>>  diff --git a/arch/mips/jz4740/setup.c b/arch/mips/jz4740/setup.c
>>  index afb40f8bce96..5c00064937c4 100644
>>  --- a/arch/mips/jz4740/setup.c
>>  +++ b/arch/mips/jz4740/setup.c
>>  @@ -31,6 +31,7 @@
>> 
>>   #define JZ4740_EMC_SDRAM_CTRL 0x80
>> 
>>  +extern const char __appended_dtb;
> 
> Does this build/link with MIPS_NO_APPENDED_DTB? I would assume it
> won't be able to resolve the symbol in that case.

Oops. You're right.

> You can also just use fw_passed_dtb from asm/bootinfo.h, which will be
> populated automatically from fw_args (if UHI) or __appended_dtb (if
> present and valid)[1], without having to care where it came from.

Thanks, I will.

Regards,
-Paul