Re: [PATCH v12 6/9] usb: xhci: use bus->sysdev for DMA configuration

[Vivek Gautam]

On Thu, Feb 9, 2017 at 7:11 AM, Peter Chen <hzpeterchen@xxxxxxxxx> wrote:
> On Wed, Feb 08, 2017 at 12:43:00PM -0800, Jack Pham wrote:
>> Hi Peter, Sriram, Arnd,
>>
>> On Mon, Feb 06, 2017 at 05:13:38PM +0800, Peter Chen wrote:
>> > From: Arnd Bergmann <arnd@xxxxxxxx>
>> >
>> > For xhci-hcd platform device, all the DMA parameters are not
>> > configured properly, notably dma ops for dwc3 devices. So, set
>> > the dma for xhci from sysdev. sysdev is pointing to device that
>> > is known to the system firmware or hardware.
>> >
>> > Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>
>> > Signed-off-by: Sriram Dash <sriram.dash@xxxxxxx>
>> > Tested-by: Baolin Wang <baolin.wang@xxxxxxxxxx>
>> > Tested-by: Vivek Gautam <vivek.gautam@xxxxxxxxxxxxxx>
>> > Tested-by: Alexander Sverdlin <alexander.sverdlin@xxxxxxxxx>
>> > Signed-off-by: Mathias Nyman <mathias.nyman@xxxxxxxxxxxxxxx>
>> > ---
>> > diff --git a/drivers/usb/host/xhci-plat.c b/drivers/usb/host/xhci-plat.c
>> > index 6d33b42..7a9c860 100644
>> > --- a/drivers/usb/host/xhci-plat.c
>> > +++ b/drivers/usb/host/xhci-plat.c
>>
>> > -   hcd = usb_create_hcd(driver, &pdev->dev, dev_name(&pdev->dev));
>> > +   hcd = __usb_create_hcd(driver, sysdev, &pdev->dev,
>> > +                          dev_name(&pdev->dev), NULL);
>>
>> As mentioned already in [1], usb_create_shared_hcd() is called to create
>> the second bus, however it also needs to be converted.
>>
>> Not exactly as Roger's suggestion but this worked for me:
>>
>> -       xhci->shared_hcd = usb_create_shared_hcd(driver, &pdev->dev,
>> +       xhci->shared_hcd = __usb_create_hcd(driver, sysdev, &pdev->dev,
>>                         dev_name(&pdev->dev), hcd);
>>         if (!xhci->shared_hcd) {
>>                 ret = -ENOMEM;
>>
>> Without this, SuperSpeed devices fail to enumerate:
>>
>>  usb 2-1: new SuperSpeed USB device number 2 using xhci-hcd
>>  usb 2-1: device descriptor read/8, error -11
>>  usb 2-1: new SuperSpeed USB device number 2 using xhci-hcd
>>  usb 2-1: device descriptor read/8, error -11
>>  usb 2-1: new SuperSpeed USB device number 3 using xhci-hcd
>>  usb 2-1: device descriptor read/8, error -11
>>  usb 2-1: new SuperSpeed USB device number 3 using xhci-hcd
>>  usb 2-1: device descriptor read/8, error -11
>>  <and continues...>
>>
>> Thanks,
>> Jack
>>
>
> Do you work at same platform with Vivek Gautam? I see his tested-by
> tag in this patch.

The patches [1] had worked for me on 4.9-rc4.
But with
(a) usb-next merged on 4.10-rc7
(b) this patch and [PATCH 3/9] in this series:
      [PATCH v12 3/9] usb: separate out sysdev pointer from usb_bus
and,
(c) phy patches for msm8996 [2] along with necessary device tree patches
I get a hang when SuperSpeed device is being enumerated on db820c.

The change above suggested by Jack works for me too, and i hope that's
the right way to do things.

I can give a Tested-by again with the changes for shared_hcd in the
next version.

[1] https://lkml.org/lkml/2016/11/17/339
[2] https://lkml.org/lkml/2017/1/10/225

>
> I have no dwc3 platform to test, I only got patches from [1], and rebase to
> Greg's usb-next, the rebase has a conflict, and I made a
> change which is similar to revert below patch, but it is definitely
> not your problem.
>
> commit 488dc164914ff5ce5e913abd32048d28fc0d06b8
> Author: Mathias Nyman <mathias.nyman@xxxxxxxxxxxxxxx>
> Date:   Fri Jan 20 15:38:24 2017 +0200
>
>     xhci: remove WARN_ON if dma mask is not set for platform devices
>
>
> [1] http://www.spinics.net/lists/linux-usb/msg152375.html
>
> --
>
> Best Regards,
> Peter Chen
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