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

[Felipe Balbi]

santosh shilimkar <santosh.shilimkar@xxxxxxxxxx> writes:
> +Arnd, RMK,
>
> On 4/1/2016 4:57 AM, Felipe Balbi wrote:
>>
>> Hi,
>>
>> Grygorii Strashko <grygorii.strashko@xxxxxx> writes:
>>> On 04/01/2016 01:20 PM, Felipe Balbi wrote:
>
> [...]
>
>>> commit 7ace8fc8219e4cbbfd5b4790390d9a01a2541cdf
>>> Author: Yoshihiro Shimoda <yoshihiro.shimoda.uh@xxxxxxxxxxx>
>>> 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@xxxxxxxxxxx>
>>>      Signed-off-by: Felipe Balbi <balbi@xxxxxx>
>>>
>>> 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 ?
>>
> The expectation is drivers should pass the proper dev pointers and let 
> core DMA code deal with it since it knows the per device dma properties.

okay, so how do you get proper DMA pointers with something like this:

	kdwc3_dma_mask = dma_get_mask(dev);
	dev->dma_mask = &kdwc3_dma_mask;

This doesn't anything.

-- 
balbi

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