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

[Andrew Bradford]

Hi Simon,

On 08/10 21:07, Simon Glass wrote:
> Hi Bin,
> 
> On 10 August 2015 at 20:53, Bin Meng <bmeng.cn at gmail.com> wrote:
> > Hi Andrew,
> >
> > On Mon, Aug 10, 2015 at 7:32 PM, Andrew Bradford
> > <andrew at 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 at 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 at gmail.com> wrote:
> >>> >> > On Fri, Aug 7, 2015 at 8:36 PM, Andrew Bradford
> >>> >> > <andrew at bradfordembedded.com> wrote:
> >>> >> >> From: Andrew Bradford <andrew.bradford at 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 at kodakalaris.com>
> >>> >> >> ---
> >>> >> >>
> >>> >> >
> >>> >> > Reviewed-by: Bin Meng <bmeng.cn at gmail.com>
> >>> >> > Tested-by: Bin Meng <bmeng.cn at gmail.com>
> >>> >> >
> >>> >>
> >>> >> Acked-by: Simon Glass <sjg at chromium.org>
> >>> >> Tested on minnowmax:
> >>> >> Tested-by: Simon Glass <sjg at 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.

Minnowmax has a USB power switch enable which determines if the VBUS2
net is turned on or not, which will supply or not supply power to the
USB 2.0 port.  The blue USB 3.0 port also has an enable.  Both enables
and the USB ports themselves are located on page 16 of the schematic
that I have.

The switches to enable the VBUS for each port are active high and pulled
down.  So to turn them on, I believe that's the point of the pinmuxing
and GPIO settings which are used in the minnowmax.dts.  Can you verify
if these are correctly turning on VBUS2 (since it sounds like they are
turning on VBUS1)?  If not, when you turn these GPIO on manually, does
the USB 2.0 port work correctly?

> 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, sounds good!

Thanks!
-Andrew