linux-kernel - Re: [PATCH v3 2/2] usb:dwc3: pass arch data to xhci-hcd child

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Message-ID: <878u0x8ru4.fsf@intel.com>
Date:	Fri, 01 Apr 2016 14:57:07 +0300
From:	Felipe Balbi <felipe.balbi@...ux.intel.com>
To:	Grygorii Strashko <grygorii.strashko@...com>,
	"Thang Q. Nguyen" <tqnguyen@....com>
Cc:	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	linux-usb@...r.kernel.org, linux-omap@...r.kernel.org,
	linux-kernel@...r.kernel.org, linux-arm@...ts.infradead.org,
	Arnd Bergmann <arnd@...db.de>,
	"Karicheri\, Muralidharan" <m-karicheri2@...com>,
	Peter Ujfalusi <peter.ujfalusi@...com>, Phong Vo <pvo@....com>,
	Loc Ho <lho@....com>, patches <patches@....com>,
	Santosh Shilimkar <ssantosh@...nel.org>,
	"Ben Dooks \(embedded platforms\)" <ben-linux@...ff.org>
Subject: Re: [PATCH v3 2/2] usb:dwc3: pass arch data to xhci-hcd child


Hi,

Grygorii Strashko <grygorii.strashko@...com> writes:
> On 04/01/2016 01:20 PM, Felipe Balbi wrote:
>> 
>> Hi,
>> 
>> Grygorii Strashko <grygorii.strashko@...com> writes:
>>>> if of_dma_configure() does what you want, why don't you just stick it in
>>>> dwc3-keystone.c and let the driver continue to copy things for now ?
>>>> Something like below, perhaps ?
>>>>
>>>
>>> I know (and i have patch to fix that which I'm going to send) that DMA config
>>>   in dwc3-keystone.c is not correct and we are good till now just
>>> because dwc3_keystone is not used for DMA operations directly.
>>>
>>> Now about xhci and friends:
>>> dwc3_keystone *is created* from DT : of_platform_device_create() -> of_platform_device_create_pdata() -> of_dma_configure()
>>> |- dwc3 *is created* from DT : of_platform_device_create() -> of_platform_device_create_pdata() -> of_dma_configure()
>>>     |- [1] *creates* xhci dev manually : DMA configuration copied manually in dwc3_host_init()
>>>     |- [2] *creates* usb_gadget dev manually: DMA configuration copied manually in usb_add_gadget_udc_release()
>>>     |- *creates* usb_udc dev manually : not used for DMA operations directly (as I've checked)
>>>
>>> Now cases [1] & [2] introduces failures, because DMA configuration is not complete for
>>> these devices.
>> 
>> right, then we just copy whatever's missing, right ? Until there's a
>> generic way of copying these bits, I want to avoid introducing any of_*
>> specific methodologies and prefer to have the manual copy.
>
> Sry, I've found no other way (right now) to fix it, except by using of_dma_configure()
> which will do all work in DT case (including calling of arch specific callbacks).
> [it might be unsafe to just copy archdata, for example, as it might(will for arm)
>  contain pointers] 
>
>> 
>>> I can confirm that if I fix [1] & [2] as above USB Device/Dual modes will start
>>> working on K2E.
>
> Above is for 4.1 kernel
>
>> 
>> cool, I'd be happy to take both patches ;-)
>> 
>
> ok. And seems gadget case is fixed already
> commit 7ace8fc8219e4cbbfd5b4790390d9a01a2541cdf
> Author: Yoshihiro Shimoda <yoshihiro.shimoda.uh@...esas.com>
> Date:   Mon Jul 13 18:10:05 2015 +0900
>
>     usb: gadget: udc: core: Fix argument of dma_map_single for IOMMU
>     
>     The dma_map_single and dma_unmap_single should set "gadget->dev.parent"
>     instead of "&gadget->dev" in the first argument because the parent has
>     a udc controller's device pointer.
>     Otherwise, iommu functions are not called in ARM environment.
>     
>     Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@...esas.com>
>     Signed-off-by: Felipe Balbi <balbi@...com>
>
> Above actually means that DMA configuration code can be dropped from
> usb_add_gadget_udc_release() completely. Right?:

true, but now I'm not sure what's better: copy all necessary bits from
parent or just pass the parent device to all DMA API.

Anybody to shed a light here ?

-- 
balbi

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