[U-Boot] [PATCH] arm: socfpga: provide default SPL_SIZE_LIMIT for gen5

[Marek Vasut]

On 6/13/19 10:26 PM, Simon Goldschmidt wrote:
> 
> 
> On 13.06.19 22:14, Marek Vasut wrote:
>> On 6/13/19 9:50 PM, Simon Goldschmidt wrote:
>>> This provides an SPL_SIZE_LIMIT that makes the build check that the SPL
>>> binary loaded from flash fits into the SRAM (64 KiB) and leaves enough
>>> room for global data, heap  and stack (512 bytes assumed stack usage).
>>>
>>> Signed-off-by: Simon Goldschmidt <simon.k.r.goldschmidt at gmail.com>
>>> ---
>>>
>>>   arch/arm/mach-socfpga/Kconfig | 8 ++++++++
>>>   1 file changed, 8 insertions(+)
>>>
>>> diff --git a/arch/arm/mach-socfpga/Kconfig
>>> b/arch/arm/mach-socfpga/Kconfig
>>> index 48f02f08d4..1d914648e3 100644
>>> --- a/arch/arm/mach-socfpga/Kconfig
>>> +++ b/arch/arm/mach-socfpga/Kconfig
>>> @@ -3,6 +3,12 @@ if ARCH_SOCFPGA
>>>   config NR_DRAM_BANKS
>>>       default 1
>>>   +config SPL_SIZE_LIMIT
>>> +    default 65536 if TARGET_SOCFPGA_GEN5
>>> +
>>> +config SPL_SIZE_LIMIT_PROVIDE_STACK
>>> +    default 0x200 if TARGET_SOCFPGA_GEN5
>>> +
>>>   config SPL_STACK_R_ADDR
>>>       default 0x00800000 if TARGET_SOCFPGA_GEN5
>>>   @@ -49,6 +55,8 @@ config TARGET_SOCFPGA_GEN5
>>>       bool
>>>       select SPL_ALTERA_SDRAM
>>>       imply FPGA_SOCFPGA
>>> +    imply SPL_SIZE_LIMIT_SUBTRACT_GD
>>> +    imply SPL_SIZE_LIMIT_SUBTRACT_MALLOC
>>>       imply SPL_STACK_R
>>>       imply SPL_SYS_MALLOC_SIMPLE
>>>       imply USE_TINY_PRINTF
>>>
>> 512 bytes for stack looks like it's too little. I think the SPL started
>> misbehaving when it overgrew 50 kiB, no ?
> 
> To 1: Well, I tested the stack usage once, booting from eMMC, and was
> somewhere below that range. But yes, it's a problem for the future: once
> we get a more stack-consuming function, we might be lost. Which size
> would you suggest?

Hmmm, now that I think about it, the stack gets relocated to DRAM quite
early too, right ? So maybe we really don't need that much space for stack.

> To 2: No. The documentation says 60 KiB would be the limit (upper 4 KiB
> reserved for BootRom usage while loading SPL). I'm running SPL with the
> DM_CLK driver (still under development) with a binary (code + dtb) of
> about 58 KiB and it runs fine. Heap size before relocation increases to
> around 4KiB though, so that ensures the 60 KiB limit isn't breached.

OK, thanks for checking.

-- 
Best regards,
Marek Vasut