Re: [PATCH V2 2/3] ARM: shmobile: r8a7790: Add PCI USB host clock support

[Ben Dooks <ben.dooks@codethink.co.uk>]

On 28/01/14 00:28, Magnus Damm wrote:
> On Fri, Jan 24, 2014 at 8:37 PM, Ben Dooks <ben.dooks@codethink.co.uk> wrote:
>> On 24/01/14 04:47, Magnus Damm wrote:
>>>
>>> On Sat, Jan 18, 2014 at 3:20 AM, Valentine Barshak
>>> <valentine.barshak@cogentembedded.com> wrote:
>>>>
>>>> This adds internal PCI USB host clock support.
>>>>
>>>> Signed-off-by: Valentine Barshak <valentine.barshak@cogentembedded.com>
>>>> ---
>>>>    arch/arm/mach-shmobile/clock-r8a7790.c | 6 +++++-
>>>>    1 file changed, 5 insertions(+), 1 deletion(-)
>>>>
>>>> Changes in V2:
>>>> * capitalized ARM in the subject;
>>>> * rebased on top the latest devel tag.
>>>
>>>
>>> This patch for PCI USB clock support seems fine to me.
>>>
>>> Acked-by: Magnus Damm <damm@opensource.se>
>>>
>>> It is common practice that maintainers reject code to encourage people
>>> to do further development. I don't think that will help us in this
>>> particular case, so I think it is best to merge this as-is but also
>>> request you to spend your future time on DT development.
>>>
>>> So please work on DT reference support together with CCF for PCI USB.
>>
>>
>> I've already posted a series for getting this device treeed.
>
> Thanks for that!
>
>> As a note, does channel 0 work for you? we are getting a lot of
>> failures with the OHCI controller failing to start with what looks
>> like a bus-master failure.
>
> I've only used USB0 as USBHS, and due to lack of cable detection
> hardware support on Lager (and me missing the cable needed for host) I
> plan on simply fixing USB0 as USBHS Function. Anyone wanting to test
> USB PCI Host should in my opinion use USB1 on Lager. USB2 is also fine
> until USB 3.0 support is tied in there.
>
> As both you and I have noted, the USB PCI stuff can't work well as-is
> due to mismatch in physical address space between the PCI hardware and
> the actual memory on Lager. So as we discussed, bounce buffers would
> be needed and perhaps also IOMMU support but my feeling is that may as
> well be for later in case of USB.
>
> So until I see USB PCI bounce buffer support or similar I will simply
> assume all errors on USB PCI on r8a7790 and r8a7791 are related to
> physical address size mismatch and lacking software support. Do you
> have anything that points in a different direction?
>
> Does USB1 and/or USB2 work for you as-is today?

Yes, although I have been doing my initial testing with the RAM size
limited to 1GiB of memory.

I've found a couple of minor issues with the PCI bridge driver that
so far have not actually fixed my problem which I hope to get reviewed
and sent to the lists today.

I am going to try the 'legacy' boot method today and see if I get the
same problems, just to verify if the problem is with the fdt conversion
or there is an issue with my board/code.

-- 
Ben Dooks				http://www.codethink.co.uk/
Senior Engineer				Codethink - Providing Genius