[U-Boot] U-Boot Rockchip dwc_hcd question for low-speed devices

[Simon Glass]

Hi Josh,

On 21 December 2015 at 07:11, Josh Sanford <joshs6502 at gmail.com> wrote:
> Thanks Simon.  I'm having difficulty finding anything by Stefan Bruns around
> that time frame, or much of anything recent pertaining to DWC.  (I only
> checked the u-boot-denx.git and u-boot-rockchip.git branches.)  Am I looking
> in the wrong place?

This is just patches at present - see here:

http://patchwork.ozlabs.org/project/uboot/list/?submitter=67055&state=*

Regards,
Simon

>
> On Sat, Dec 19, 2015 at 3:30 PM, Simon Glass <sjg at chromium.org> wrote:
>>
>> +Marek, Stephen
>>
>> Hi Josh,
>>
>> On 18 December 2015 at 06:26, Josh Sanford <joshs6502 at gmail.com> wrote:
>> > All,
>> >
>> > I am trying to use USB within U-Boot on a Firefly RK3288 (Rockchip)
>> > board,
>> > and I am able to enumerate high-speed devices, but not full-speed or
>> > low-speed devices.  I know that the devices are functional, because they
>> > work on the same physical hardware when I boot into Linux.  Note that
>> > I'm
>> > using "U-Boot 2014.10-RK3288-02".
>> >
>> > As an aside, the built-in "USB 2.0 Hub [MTT]" hub never generates a
>> > USB_PORT_STAT_C_CONNECTION for me, even though USB_PORT_STAT_CONNECTION
>> > goes
>> > high immediately after powering on, so I forcibly assert
>> > USB_PORT_STAT_C_CONNECTION to allow the rest of the tree to enumerate.
>> >
>> > High-speed devices can be nested as deeply as I wish and still show up
>> > properly, but I can't get low-speed devices (i.e. a keyboard) to work in
>> > any
>> > hub port, including any of the ports directly on the board.  All
>> > attempts to
>> > read from my low-speed devices return all zeros.  When I dig a little
>> > deeper, I find myself in int dwc_wait_for_complete(struct usb_device
>> > *dev,
>> > uint32_t channel_num, uint32_t *hcStat, uint32_t *errCnt) {}.
>> >
>> > On the second iteration through the goto loop, hcintn.b.chhltd and
>> > hcintn.b.xacterr are both asserted, but hcintn.b.ack, hcintn.b.nak, and
>> > hcintn.b.nyet are not, and errCnt is only 1, so the code sets *hcStat =
>> > HCSTAT_REINIT and returns.
>> >
>> > I do notice that dwc_hcd.c seems not to have any code to support split
>> > transactions (or perhaps I simply haven't seen it yet).  If true, I
>> > wonder
>> > whether this code is actually expected to support full-speed and
>> > low-speed
>> > devices.  Do you have any thoughts on the matter?  I wish I were more of
>> > a
>> > USB expert, but I'm regrettably quite a novice.
>>
>> I believe the split transaction issue is currently being resolved for
>> DWC. See for example Stefan Bruns' series from 13th December. It might
>> be worth trying that out.
>>
>> Regards,
>> Simon
>
>