From: Christoph Hellwig <hch@lst.de>
To: linux-aspeed@lists.ozlabs.org
Subject: [PATCH] usb: gadget: aspeed: set port_dev dma mask
Date: Mon, 29 Mar 2021 08:17:35 +0200 [thread overview]
Message-ID: <20210329061735.GA27510@lst.de> (raw)
In-Reply-To: <20210327221759.GA2997@taoren-ubuntu-R90MNF91>
On Sat, Mar 27, 2021 at 03:17:59PM -0700, Tao Ren wrote:
> On Fri, Mar 26, 2021 at 01:05:26PM +0100, Christoph Hellwig wrote:
> > On Fri, Mar 26, 2021 at 12:03:03PM +0000, Robin Murphy wrote:
> > > This might happen to work out, but is far from correct. Just wait until you
> > > try it on a platform where the USB controller is behind an IOMMU...
> > >
> > > It looks like something is more fundamentally wrong here - the device
> > > passed to DMA API calls must be the actual hardware device performing the
> > > DMA, which in USB-land I believe means the controller's sysdev.
> >
> > The shiny new usb_intf_get_dma_device API provides the device to use.
>
> Thanks Robin and Christoph for the feedback.
>
> If I understand correctly, usb_intf_get_dma_device API is mainly for usb
> host drivers? I just found usb_gadget_map_request_by_dev API: does it
> make sense to replace usb_gadget_map_request with
> usb_gadget_map_request_by_dev so we can pass the actual DMA-capable
> hardware device (aspeed-vhub platform device) to the API?
Oh, right you're dealing with a gadget side driver. Not sure about
the API there, I'll let the relevant maintainers chime in.
next prev parent reply other threads:[~2021-03-29 6:17 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-26 7:02 [PATCH] usb: gadget: aspeed: set port_dev dma mask rentao.bupt
[not found] ` <10920f34-289c-feac-79b6-71bff2aea67d@arm.com>
2021-03-26 12:05 ` Christoph Hellwig
2021-03-27 22:17 ` Tao Ren
2021-03-29 6:17 ` Christoph Hellwig [this message]
2021-03-31 3:47 ` Tao Ren
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