From: Tao Ren <rentao.bupt@gmail.com>
To: Christoph Hellwig <hch@lst.de>
Cc: Sasha Levin <sashal@kernel.org>, Felipe Balbi <balbi@kernel.org>,
Ryan Chen <ryan_chen@aspeedtech.com>,
kernel test robot <lkp@intel.com>,
linux-aspeed@lists.ozlabs.org,
Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>,
Andrew Jeffery <andrew@aj.id.au>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Masahiro Yamada <masahiroy@kernel.org>,
linux-usb@vger.kernel.org, Tao Ren <taoren@fb.com>,
linux-kernel@vger.kernel.org, openbmc@lists.ozlabs.org,
Robin Murphy <robin.murphy@arm.com>,
Thomas Tai <thomas.tai@oracle.com>,
linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH] usb: gadget: aspeed: set port_dev dma mask
Date: Tue, 30 Mar 2021 20:47:02 -0700 [thread overview]
Message-ID: <20210331034701.GA3185@taoren-ubuntu-R90MNF91> (raw)
In-Reply-To: <20210329061735.GA27510@lst.de>
On Mon, Mar 29, 2021 at 08:17:35AM +0200, Christoph Hellwig wrote:
> 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.
Given this is not the right path, I will drop the patch and work out a
new fix soon (by calling usb_gadget_map_request_by_dev, and with
modified subject).
Cheers,
Tao
prev parent reply other threads:[~2021-03-31 3:47 UTC|newest]
Thread overview: 6+ 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
2021-03-26 12:03 ` Robin Murphy
2021-03-26 12:05 ` Christoph Hellwig
2021-03-27 22:17 ` Tao Ren
2021-03-29 6:17 ` Christoph Hellwig
2021-03-31 3:47 ` Tao Ren [this message]
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