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

[Andrew Bradford]

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.

I enabled the MRC debug messages as it was helpful to me as there are a
set of FSP UPD device tree properties which during my development turned
out to boot enough for the MRC code in the FSP to run but which would
not actually end up starting u-boot.  At least having the MRC debug
message print out showed me that at least u-boot was operating enough to
call into the FSP and that likely I had something misconfigured in the
UPD memory settings.  Probably not showing these debug messages is the
right choice, as if someone wants more debug output then they can also
use the FSPv4 debug build that Intel now provides.

Thanks for your help with this patch! :)
-Andrew