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

[Roger Quadros]

On 09/02/17 13:53, Roger Quadros wrote:
> 
> 
> On 08/02/17 22:43, 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);
> 
> But we're creating a shared_hcd and there is an API for that so why not use it
> instead of calling __usb_create_hcd()?
> 

Just realized after I pressed send that there is no sysdev parameter
for create_shared_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
>>
>> [1] https://lkml.org/lkml/2016/12/9/240
>>
> 

-- 
cheers,
-roger