[U-Boot] [PATCH v3] armv8: fsl-layerscale: Rewrite reserving memory for MC and debug server

[Simon Glass]

Hi York,

On 7 December 2015 at 11:03, York Sun <yorksun at freescale.com> wrote:
>
>
> On 12/07/2015 09:54 AM, Simon Glass wrote:
>> Hi York,
>>
>> On 7 December 2015 at 10:43, York Sun <yorksun at freescale.com> wrote:
>>>
>>>
>>>
>>> On 11/22/2015 09:53 AM, York Sun wrote:
>>>>
>>>>
>>>> On 11/22/2015 08:11 AM, Simon Glass wrote:
>>>>> Hi York,
>>>>>
>>>
>>> <snip>
>>>
>>>>>> diff --git a/common/board_f.c b/common/board_f.c
>>>>>> index 8061105..2fd1c21 100644
>>>>>> --- a/common/board_f.c
>>>>>> +++ b/common/board_f.c
>>>>>> @@ -316,6 +316,15 @@ __weak ulong board_get_usable_ram_top(ulong total_size)
>>>>>>         return gd->ram_top;
>>>>>>  }
>>>>>>
>>>>>> +__weak phys_size_t board_reserve_ram_top(phys_size_t ram_size)
>>>>>> +{
>>>>>> +#ifdef CONFIG_SYS_MEM_TOP_HIDE
>>>>>> +       return ram_size - CONFIG_SYS_MEM_TOP_HIDE;
>>>>>> +#else
>>>>>> +       return ram_size;
>>>>>> +#endif
>>>>>> +}
>>>>>> +
>>>>>>  static int setup_dest_addr(void)
>>>>>>  {
>>>>>>         debug("Monitor len: %08lX\n", gd->mon_len);
>>>>>> @@ -332,19 +341,17 @@ static int setup_dest_addr(void)
>>>>>>          */
>>>>>>         gd->secure_ram = gd->ram_size;
>>>>>>  #endif
>>>>>> -#if defined(CONFIG_SYS_MEM_TOP_HIDE)
>>>>>>         /*
>>>>>>          * Subtract specified amount of memory to hide so that it won't
>>>>>>          * get "touched" at all by U-Boot. By fixing up gd->ram_size
>>>>>>          * the Linux kernel should now get passed the now "corrected"
>>>>>> -        * memory size and won't touch it either. This should work
>>>>>> -        * for arch/ppc and arch/powerpc. Only Linux board ports in
>>>>>> -        * arch/powerpc with bootwrapper support, that recalculate the
>>>>>> -        * memory size from the SDRAM controller setup will have to
>>>>>> -        * get fixed.
>>>>>> +        * memory size and won't touch it either. This has been used
>>>>>> +        * by arch/powerpc exclusively. Now ARMv8 takes advantage of
>>>>>> +        * thie mechanism. If memory is split into banks, addresses
>>>>>> +        * need to be calculated.
>>>>>>          */
>>>>>> -       gd->ram_size -= CONFIG_SYS_MEM_TOP_HIDE;
>>>>>> -#endif
>>>>>> +       gd->ram_size = board_reserve_ram_top(gd->ram_size);
>>>>>> +
>>>>>>  #ifdef CONFIG_SYS_SDRAM_BASE
>>>>>>         gd->ram_top = CONFIG_SYS_SDRAM_BASE;
>>>>>>  #endif
>>>>>
>>>>> Sorry I didn't notice this patch before...
>>>>>
>>>>> Can you use the existing board_get_usable_ram_top() for this?
>>>>>
>>>>
>>>> Simon,
>>>>
>>>> No. The "top" is not necessarily the end of memory. It is the top of
>>>> CONFIG_SYS_SDRAM_BASE + get_effective_memsize(). I am trying to avoid reserving
>>>> memory in the middle.
>>>>
>>>> I am using the same way as CONFIG_SYS_MEM_TOP_HIDE, but rewriting it with a weak
>>>> function.
>>>>
>>>
>>> Simon,
>>>
>>> If you are satisfied with my explanation, I am considering to merge this patch.
>>
>> I think this function is getting pretty complicated. Probably we need
>> to create a struct with the various parameters in it, and have a
>> single board function that is called to possibly make adjustments. At
>> present it is really hard to figure out what is going on and this
>> patch makes things worse.
>>
>> I'm fine with that happening later if you want to merge this patch
>> now. But I think it needs a look.
>>
>
> Simon,
>
> I agree we need look into this. It started to get complicated when we have more
> than 32-bit physical address. It got more complicated when the memory is divided
> into several banks (for ARMv8 case). This patch is needed if I merge another two
> patches to make DDR non-secure, which fixes some issue with non-secure masters.
> Let's spend some time after the holidays to restructure this.

OK thanks. Please send an email or a patch when you have some ideas.

Reviewed-by: Simon Glass <sjg at chromium.org>

Regards,
Simon