[U-Boot] rk3288: 32KB SPL size restriction

[Jagan Teki]

On Thu, Aug 24, 2017 at 12:28 AM, Dr. Philipp Tomsich
<philipp.tomsich at theobroma-systems.com> wrote:
>
>> On 23 Aug 2017, at 20:44, Jagan Teki <jagannadh.teki at gmail.com> wrote:
>>
>> On Wed, Aug 23, 2017 at 6:22 PM, Dr. Philipp Tomsich
>> <philipp.tomsich at theobroma-systems.com> wrote:
>>>
>>>> On 23 Aug 2017, at 13:19, Jagan Teki <jagannadh.teki at gmail.com> wrote:
>>>>
>>>> Hi Philipp,
>>>>
>>>> On Tue, Aug 22, 2017 at 5:41 PM, Dr. Philipp Tomsich
>>>> <philipp.tomsich at theobroma-systems.com> wrote:
>>>>>
>>>>>> On 22 Aug 2017, at 14:05, Jagan Teki <jagannadh.teki at gmail.com> wrote:
>>>>>>
>>>>>> Philipp and Kever - Thanks for the response.
>>>>>>
>>>>>> Few comment below.
>>>>>>
>>>>>> On Thu, Aug 17, 2017 at 2:02 PM, Dr. Philipp Tomsich
>>>>>> <philipp.tomsich at theobroma-systems.com> wrote:
>>>>>>> Jagan,
>>>>>>>
>>>>>>>> On 17 Aug 2017, at 08:39, Kever Yang <kever.yang at rock-chips.com> wrote:
>>>>>>>>
>>>>>>>> Hi Jagan,
>>>>>>>>
>>>>>>>>
>>>>>>>> On 08/10/2017 05:07 PM, Jagan Teki wrote:
>>>>>>>>> Hi Simon/Philipp or any,
>>>>>>>>>
>>>>>>>>> I believe rk3288 has 20KB BootRom and 100KB internal SRAM and current
>>>>>>>>> u-boot can archive the maximum size of u-boot-spl-dtb.bin which the
>>>>>>>>> boot ROM will read is 32KB, do we have any possibility to increase the
>>>>>>>>> SPL size here.
>>>>>>>>
>>>>>>>> The limitation is decide by the boot rom design, so we are not able
>>>>>>>> to change this. Most of Rockchip SoCs have this limitation except RK3399.
>>>>>>>>
>>>>>>>> Thanks,
>>>>>>>> - Kever
>>>>>>>>>
>>>>>>>>> # ./tools/mkimage -n rk3288 -T rksd -d ./spl/u-boot-spl-dtb.bin out.img
>>>>>>>>> Warning: SPL image is too large (size 0x9000) and will not boot
>>>>>>>>> Error: image verification failed
>>>>>>>>>
>>>>>>>>> I tried to increase the spl_size from spl_infos (on tools/rkcommon.c)
>>>>>>>>> but not able to boot.
>>>>>>>
>>>>>>> I should have read this more carefully (I only parsed the 20KB and
>>>>>>> jumped to the conclusion that your had the error already when crossing
>>>>>>> the 20KB limit—even though 0x8000 bytes where allowed in mkimage)…
>>>>>>
>>>>>> Sorry I really didn't understand the size constraint here, because SPL
>>>>>> can be boot file after ROM handoff. Can't this sit on 100KB of SRAM?
>>>>>
>>>>> The ROM usually has different size constraints for each stage.
>>>>>
>>>>> E.g. for the RK3368 (just been there, done that), the first stage has a
>>>>> 0x7000 byte limit and the next stage (loaded to 0x0 in DRAM) has a
>>>>> much larger limit. Note that the SRAM on the 3368 has a capacity of
>>>>> 0x10000 bytes, so the size limit is also quite pronounced.
>>>>
>>>> OK, by looking at your rk3368[1] patch I think the first stage runs
>>>> under 0x7000 is TPL? and next stage(probably SPL) doesn't have limit
>>>> since SPL running here in DDR since DDR initialized DDR in TPL itself.
>>>> this is what the space distributed here?
>>>
>>> Yes, although there is some size limit even for SPL.
>>> If you are going for a falcon-mode implementation on the 3288, you will
>>> probably want to use TPL for DRAM setup and maybe clocking up the
>>> cores (I don’t know the constraints on what clocks the BROM needs
>>> untouched) and then have SPL w/ falcon mode loaded by the BROM.
>>
>> So, TPL should have DDR and MMC, and fit into 0x8000 bytes and SPL
>> will load from MMC and launch u-boot. Do we need spl_bootrom in TPL
>> instead of MMC? if so where we need to copy SPL?
>
> You probably just want DRAM-init and clocking and have everything else
> in SPL (for the falcon use-case).  The BROM will magically load the SPL
> stage for you, so no need for MMC support in TPL.

How does BROM will load SPL here? with
CONFIG_SPL_ROCKCHIP_BACK_TO_BROM=y ? because I will copy TPL at 64
sector of MMC card and where should I copy SPL?

thanks!
-- 
Jagan Teki
Free Software Engineer | www.openedev.com
U-Boot, Linux | Upstream Maintainer
Hyderabad, India.