[U-Boot] [PATCH v4] x86: baytrail: Configure FSP UPD from device tree

[Bin Meng <bmeng.cn@gmail.com>]

Hi Simon,

On Tue, Aug 11, 2015 at 11:24 AM, Simon Glass <sjg@chromium.org> wrote:
> Hi Bin,
>
> On 10 August 2015 at 21:17, Bin Meng <bmeng.cn@gmail.com> wrote:
>> Hi Simon,
>>
>> On Tue, Aug 11, 2015 at 11:07 AM, Simon Glass <sjg@chromium.org> wrote:
>>> Hi Bin,
>>>
>>> On 10 August 2015 at 20:53, Bin Meng <bmeng.cn@gmail.com> wrote:
>>>> Hi Andrew,
>>>>
>>>> On Mon, Aug 10, 2015 at 7:32 PM, Andrew Bradford
>>>> <andrew@bradfordembedded.com> wrote:
>>>>> Hi Bin,
>>>>>
>>>>> On 08/09 10:52, Bin Meng wrote:
>>>>>> Hi Andrew,
>>>>>>
>>>>>> On Sun, Aug 9, 2015 at 9:08 AM, Andrew Bradford
>>>>>> <andrew@bradfordembedded.com> wrote:
>>>>>> > Hi Simon,
>>>>>> >
>>>>>> > On 08/08 10:18, Simon Glass wrote:
>>>>>> >> Hi,
>>>>>> >>
>>>>>> >> On 7 August 2015 at 06:44, Bin Meng <bmeng.cn@gmail.com> wrote:
>>>>>> >> > On Fri, Aug 7, 2015 at 8:36 PM, Andrew Bradford
>>>>>> >> > <andrew@bradfordembedded.com> wrote:
>>>>>> >> >> From: Andrew Bradford <andrew.bradford@kodakalaris.com>
>>>>>> >> >>
>>>>>> >> >> Allow for configuration of FSP UPD from the device tree which will
>>>>>> >> >> override any settings which the FSP was built with itself.
>>>>>> >> >>
>>>>>> >> >> Modify the MinnowMax and BayleyBay boards to transfer sensible UPD
>>>>>> >> >> settings from the Intel FSPv4 Gold release to the respective dts files,
>>>>>> >> >> with the condition that the memory-down parameters for MinnowMax are
>>>>>> >> >> also used.
>>>>>> >> >>
>>>>>> >> >> Signed-off-by: Andrew Bradford <andrew.bradford@kodakalaris.com>
>>>>>> >> >> ---
>>>>>> >> >>
>>>>>> >> >
>>>>>> >> > Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
>>>>>> >> > Tested-by: Bin Meng <bmeng.cn@gmail.com>
>>>>>> >> >
>>>>>> >>
>>>>>> >> Acked-by: Simon Glass <sjg@chromium.org>
>>>>>> >> Tested on minnowmax:
>>>>>> >> Tested-by: Simon Glass <sjg@chromium.org>
>>>>>> >>
>>>>>> >> I found that I need to remove two properties from the minnowmax.dts:
>>>>>> >>
>>>>>> >> - fsp,enable-xhci needs to be removed as this does not work in U-Boot
>>>>>> >> at present and stops EHCI from working
>>>>>> >> - fsp,mrc-debug-msg needs to be removed to prevent debug information
>>>>>> >> being displayed
>>>>>> >>
>>>>>> >> I plan to apply this with these changes - please let me know if this
>>>>>> >> doesn't suit.
>>>>>> >
>>>>>> > I'm OK with disabling xhci and the MRC debug output in the FSP.
>>>>>> >
>>>>>> > But if xhci is disabled then I believe when Linux boots that the USB 3.0
>>>>>> > port on Minnow Max will only act as a USB 2.0 port.  That u-boot doesn't
>>>>>> > yet have working XHCI on E3800 means there is a tradeoff and I wasn't
>>>>>> > sure which was a better choice.
>>>>>>
>>>>>> Does these xHCI ports on MinnowMax work fully on Linux kernel? If it
>>>>>> works, I'd rather we keep fsp,enable-xhci in the U-Boot.
>>>>>
>>>>> I believe that the xhci port does work on Minnow Max in Linux but I do
>>>>> not have a board so I'm unable to test, sorry.
>>>>>
>>>>
>>>> OK, my test shows that ehci works fine in U-Boot on Bayley Bay.
>>>>
>>>> Hi Simon,
>>>>
>>>> What do you think regarding to xhci vs. ehci in U-Boot?
>>>
>>> The problem is that USB is then broken in U-Boot. I think it is better
>>> to limit the speed for the moment until we have that fixed. It is
>>> quite useful to be able to use a keyboard or USB stick in U-Boot.
>>>
>>> With my testing the bottom (blue) port works fine but the top port
>>> does not. This happens regardless of the xhci setting.
>>
>> There are 3 ports on Intel Bayley Bay. One USB 3 (blue port) and two
>> USB 2 ports. The board user guide explicitly mentions that the top USB
>> 2 port does not work and needs PCB rework. For the other two ports,
>> I've tested U-Boot EHCI stack and it works fine. Interesting to hear
>> that MinnowMax also has some USB port issue. Maybe the board design is
>> following Bayley Bay.
>
> Maybe.
>
>>
>>>
>>> So overall I think we are in a better position to go with ehci for
>>> now, i.e. drop the fsp,enable-xhci property.
>>
>> OK, then could you please remove this for Bayley Bay as well? Also I
>> think we need remove the MRC debug output as well.
>
> Yes will do.
>
>>
>>>
>>> I think there is a little tweak needed to support both ports, but I
>>> haven't dug into it yet.
>>>
>>
>> This is not possible. According to Intel E3800 datasheet, the xHCI and
>> EHCI are mutually exclusive. We can either use xHCI, or EHCI.
>
> I believe you can put the ports into a mode where both work, although
> presumablly they are both either EHCI or xHCI. When I boot UEFI both
> ports work.
>

Yep, that's what I meant. When using EHCI the USB 3 port will function
as a USB 2 port and when using xHCI the USB 2 port will only get high
speed.

Regards,
Bin