[U-Boot] [PATCH v1 01/12] rockchip: define SUPPORT_SPL and SPL config in RK3288 config

[Simon Glass]

Hi,

On Oct 22, 2015 7:22 PM, "hl" <hl at rock-chips.com> wrote:
>
> Hi Simon,
>
>
> On 23/10/15 09:04, Simon Glass wrote:
>>
>> Hi Eddie,
>>
>> On 22 October 2015 at 18:54, Eddie Cai <eddie.cai at rock-chips.com> wrote:
>>>
>>> Hi Simon
>>>
>>> 2015-10-23 0:30 GMT+08:00 Simon Glass <sjg at chromium.org>:
>>>>
>>>> Hi Eddie,
>>>>
>>>> On 22 October 2015 at 10:01, Eddie Cai <eddie.cai at rock-chips.com>
wrote:
>>>>>
>>>>> Hi Simon
>>>>>
>>>>> 2015-10-22 22:07 GMT+08:00 Simon Glass <sjg at chromium.org>:
>>>>>>
>>>>>> Hi Lin,
>>>>>>
>>>>>> On 20 October 2015 at 20:37, Lin Huang <hl at rock-chips.com> wrote:
>>>>>>>
>>>>>>> it may not use SPL in other rockchip SOC, so move SUPPORT_SPL and
>>>>>>> SPL config to rk3288 configuration.
>>>>>>>
>>>>>>> Signed-off-by: Lin Huang <hl at rock-chips.com>
>>>>>>> ---
>>>>>>> Changes in v1: None
>>>>>>>
>>>>>>>   arch/arm/Kconfig               | 2 --
>>>>>>>   arch/arm/mach-rockchip/Kconfig | 2 ++
>>>>>>>   2 files changed, 2 insertions(+), 2 deletions(-)
>>>>>>>
>>>>>>> diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
>>>>>>> index 194fb7b..40fa741 100644
>>>>>>> --- a/arch/arm/Kconfig
>>>>>>> +++ b/arch/arm/Kconfig
>>>>>>> @@ -831,8 +831,6 @@ config TARGET_STM32F429_DISCOVERY
>>>>>>>
>>>>>>>   config ARCH_ROCKCHIP
>>>>>>>          bool "Support Rockchip SoCs"
>>>>>>> -       select SUPPORT_SPL
>>>>>>> -       select SPL
>>>>>>>          select OF_CONTROL
>>>>>>>          select CPU_V7
>>>>>>>          select DM
>>>>>>> diff --git a/arch/arm/mach-rockchip/Kconfig
>>>>>>> b/arch/arm/mach-rockchip/Kconfig
>>>>>>> index ab50f4e..15cd380 100644
>>>>>>> --- a/arch/arm/mach-rockchip/Kconfig
>>>>>>> +++ b/arch/arm/mach-rockchip/Kconfig
>>>>>>> @@ -2,6 +2,8 @@ if ARCH_ROCKCHIP
>>>>>>>
>>>>>>>   config ROCKCHIP_RK3288
>>>>>>>          bool "Support Rockchip RK3288"
>>>>>>> +       select SUPPORT_SPL
>>>>>>> +       select SPL
>>>>>>>          help
>>>>>>>            The Rockchip RK3288 is a ARM-based SoC with a quad-core
>>>>>>> Cortex-A17
>>>>>>>            including NEON and GPU, 1MB L2 cache, Mali-T7 graphics,
two
>>>>>>> --
>>>>>>> 1.9.1
>>>>>>>
>>>>>> We should avoid little binary blobs for booting the chip. I think we
>>>>>> can live with this as a stepping stone to having a proper SPL, but
>>>>>> what is the plan for a proper SPL in U-Boot?
>>>>>
>>>>> RK3036 have only 8k sram. 4k used by boot rom. The ddr initialize code
>>>>> is
>>>>> almost 4k. So i don't think we can do SPL.
>>>>
>>>> How does U-Boot get loaded in this case? Does it use ROM code? If so
>>>
>>> Yes, it use boot rom code to load U-Boot
>>>>
>>>> then I think we should create an SPL that handles the DDR init and
>>>> then returns to the ROM code for loading U-Boot. Also we should
>>>> document how this works in the README.
>>>
>>> It is a good news you agree we can return to boot rom from SPL. Do you
know
>>> what size of sram a smallest SPL need?
>>
>> Exynos does something a little similar - it has a jump table of ROM
>> routines that SPL can call.
>>
>> You can essentially write your own code for SPL. I very much hope you
>> can use start.S and cro0.S, but these add up to a tiny amount of code
>> so should not cause problems. You should be able to put all of your
>> code into your implementation of board_init_f(), using most of the 4KB
>> available. U-Boot's SPL framework does add some overhead, but if you
>> leave out the board_init_r() implementation this is very small.
>>
>> If you do get stuck and find the size if over 4KB we should discuss it
>> and see what can be done.
>
>
>      Okay, i will reference exynos to see how to do,  thank you.
>

One last point...  U-Boot is written in C so as much as possible of this
should be C, rather than assembler.

Regards,
Simon