[U-Boot] [PATCH 3/5] x86: queensbay: Support pre-relocation dm pci

[Bin Meng]

Hi Simon,

On Thu, Aug 6, 2015 at 10:55 AM, Simon Glass <sjg at chromium.org> wrote:
> Hi Bin,
>
> On 5 August 2015 at 20:48, Bin Meng <bmeng.cn at gmail.com> wrote:
>> Hi Simon,
>>
>> On Wed, Aug 5, 2015 at 10:39 PM, Simon Glass <sjg at chromium.org> wrote:
>>> Hi Bin,
>>>
>>> On 2 August 2015 at 19:52, Bin Meng <bmeng.cn at gmail.com> wrote:
>>>> Hi Simon,
>>>>
>>>> On Mon, Aug 3, 2015 at 6:31 AM, Simon Glass <sjg at chromium.org> wrote:
>>>>> Hi Bin,
>>>>>
>>>>> On 27 July 2015 at 01:33, Bin Meng <bmeng.cn at gmail.com> wrote:
>>>>>> Increase CONFIG_MALLOC_F_LEN so that dm pci does not fail with -ENOMEM
>>>>>> before relocation. This makes pci uart work again on Intel Crown Bay.
>>>>>>
>>>>>> Signed-off-by: Bin Meng <bmeng.cn at gmail.com>
>>>>>> ---
>>>>>>
>>>>>>  arch/x86/cpu/queensbay/Kconfig |  3 +++
>>>>>>  arch/x86/cpu/queensbay/tnc.c   | 13 +++++++++++++
>>>>>>  arch/x86/dts/crownbay.dts      |  2 --
>>>>>>  3 files changed, 16 insertions(+), 2 deletions(-)
>>>>>>
>>>>>> diff --git a/arch/x86/cpu/queensbay/Kconfig b/arch/x86/cpu/queensbay/Kconfig
>>>>>> index fbf85f2..8eb619c 100644
>>>>>> --- a/arch/x86/cpu/queensbay/Kconfig
>>>>>> +++ b/arch/x86/cpu/queensbay/Kconfig
>>>>>> @@ -42,4 +42,7 @@ config CPU_ADDR_BITS
>>>>>>         int
>>>>>>         default 32
>>>>>>
>>>>>> +config SYS_MALLOC_F_LEN
>>>>>> +       default 0x8000
>>>>>
>>>>> 32KB? Wow that's a huge amount. How much does it actually use? Perhaps
>>>>> we should change PCI so that it respects the u-boot,dm-pre-reloc
>>>>> property?
>>>>>
>>>>
>>>> I just add a zero to the original value :) I did not measure the
>>>> actual memory consumption since after fsp_init() we have plenty of
>>>> memory to be used as the stack. For queensbay platform, it has lots of
>>>> pci devices each of which will need allocate some memory for dm pci to
>>>> use.
>>>
>>> I think it is worth checking this and using a value closer to what you
>>> need. board_init_f.c has a debug output for it I think.
>>>
>>
>> OK, I will have a check.
>>
>>> Also I wonder if we can avoid creating PCI devices for everything
>>> pre-relocation, when we only need serial?
>>>
>>
>> Yes, looks that we only need serial. However x86 is a specific case
>> since pci bus is the fundamental bus that is used to set up other
>> devices. After conversion to dm pci, if we implement it correctly, any
>> call to a pci api will trigger the enumeration and it is probably a
>> side effect of using dm?  I even think we can hardcoded pci uart in
>> the pre-relocation phase without using dm at all, but that is not a
>> portable way.
>
> Yes that's right. Of course for the UART we can do a special case at
> least for the debug UART, since that should be available early (before
> DM).
>
> How about this:
>
> - early stage, before board_init_f(): use special x86 PCI functions, enable UART
> - pre-reloc: set up only a few devices which are needed before relocation
> - post-reloc: full scan of PCI
>

This sounds good. I will need do more investigation on this.

Regards,
Bin