2019-02-21 20:40:56

by Paul Cercueil

Subject: [PATCH] MIPS: ingenic: Add support for appended devicetree

Add support for booting the kernel from an externally-appended
devicetree, if no devicetree was built-in.

Signed-off-by: Paul Cercueil <[email protected]>
---
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;

static void __init jz4740_detect_mem(void)
{
@@ -66,15 +67,22 @@ static unsigned long __init get_board_mach_type(const void *fdt)
void __init plat_mem_setup(void)
{
int offset;
+ void *dtb;

jz4740_reset_init();
- __dt_setup_arch(__dtb_start);

- offset = fdt_path_offset(__dtb_start, "/memory");
+ if (__dtb_start != __dtb_end)
+ dtb = __dtb_start;
+ else
+ dtb = (void *)&__appended_dtb;
+
+ __dt_setup_arch(dtb);
+
+ offset = fdt_path_offset(dtb, "/memory");
if (offset < 0)
jz4740_detect_mem();

- mips_machtype = get_board_mach_type(__dtb_start);
+ mips_machtype = get_board_mach_type(dtb);
}

void __init device_tree_init(void)
--
2.11.0

2019-02-21 21:14:42

by Jonas Gorski

Subject: Re: [PATCH] MIPS: ingenic: Add support for appended devicetree

On Thu, 21 Feb 2019 at 21:39, Paul Cercueil <[email protected]> wrote:
>
> Add support for booting the kernel from an externally-appended
> devicetree, if no devicetree was built-in.
>
> Signed-off-by: Paul Cercueil <[email protected]>
> ---
> 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.

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.

Regards
Jonas

[1] https://elixir.bootlin.com/linux/latest/source/arch/mips/kernel/head.S#L96

2019-02-21 21:51:38

by Paul Cercueil

Subject: Re: [PATCH] MIPS: ingenic: Add support for appended devicetree

Hi Jonas,

On Thu, 21 Feb 2019 at 21:39, Jonas Gorski <[email protected]>
wrote:
> On Thu, 21 Feb 2019 at 21:39, Paul Cercueil <[email protected]>
> wrote:
>>
>> Add support for booting the kernel from an externally-appended
>> devicetree, if no devicetree was built-in.
>>
>> Signed-off-by: Paul Cercueil <[email protected]>
>> ---
>> 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