[PATCH 4/6] usb: xhci-pci: Move reset logic out of XHCI core

[Samuel Holland]

On 2/8/21 8:27 PM, Samuel Holland wrote:
> On 2/8/21 5:43 AM, Marek Vasut wrote:
>> On 2/8/21 6:57 AM, Samuel Holland wrote:
>>> Resetting an XHCI controller inside xhci_register undoes any register
>>> setup performed by the platform driver. And at least on the Allwinner
>>> H6, resetting the XHCI controller also resets the PHY, which prevents
>>> the controller from working. That means the controller must be taken out
>>> of reset before initializing the PHY, which must be done before calling
>>> xhci_register.
>>>
>>> The logic in the XHCI core was added to support the Raspberry Pi 4
>>> (although this was not mentioned in the commit log!), which uses the
>>> xhci-pci platform driver. Move the reset logic to the platform driver,
>>> where it belongs, and where it cannot interfere with other platform
>>> drivers.
>>
>> Are there any other XHCI drivers using the XHCI core code which might
>> stop resetting correctly due to this patch ?
> 
> Since commit 0b80371b350e was merged, the only new call to xhci_register
> is in USB_MTU3. Neither the binding for "mediatek,mtu3" nor any device
> tree node containing that compatible string has a "resets" property. And
> there have been no calls to reset_(de)assert since then, either. So I do

...no calls to reset_(de)assert *removed from any driver* since then...

> not see any other drivers that would be likely to break.
> 
> Samuel
>