From: Arnd Bergmann <arnd@arndb.de>
To: linux-arm-kernel@lists.infradead.org
Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>,
Felipe Balbi <balbi@kernel.org>,
Grygorii Strashko <grygorii.strashko@ti.com>,
Russell King - ARM Linux <linux@arm.linux.org.uk>,
Catalin Marinas <catalin.marinas@arm.com>,
Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>,
"linux-usb@vger.kernel.org" <linux-usb@vger.kernel.org>,
Sekhar Nori <nsekhar@ti.com>, lkml <linux-kernel@vger.kernel.org>,
Stuart Yoder <stuart.yoder@nxp.com>,
Scott Wood <oss@buserror.net>,
David Fisher <david.fisher1@synopsys.com>,
"Thang Q. Nguyen" <tqnguyen@apm.com>, Leo Li <pku.leo@gmail.com>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Alan Stern <stern@rowland.harvard.edu>,
Robin Murphy <robin.murphy@arm.com>,
Peter Chen <hzpeterchen@gmail.com>
Subject: Re: [PATCH] usb: dwc3: host: inherit dma configuration from parent dev
Date: Wed, 14 Sep 2016 23:50:20 +0200 [thread overview]
Message-ID: <5948102.1fQRRodOXz@wuerfel> (raw)
In-Reply-To: <20160914163136.GA26842@red-moon>
On Wednesday, September 14, 2016 5:31:36 PM CEST Lorenzo Pieralisi wrote:
> On Wed, Sep 07, 2016 at 01:47:22PM +0300, Felipe Balbi wrote:
> >
> > Hi,
> >
> > Robin Murphy <robin.murphy@arm.com> writes:
> > > On 07/09/16 10:55, Peter Chen wrote:
> > > [...]
> > >>> Regarding the DMA configuration that you mention in ci_hdrc_add_device(),
> > >>> I think we should replace
> > >>>
> > >>> pdev->dev.dma_mask = dev->dma_mask;
> > >>> pdev->dev.dma_parms = dev->dma_parms;
> > >>> dma_set_coherent_mask(&pdev->dev, dev->coherent_dma_mask);
> > >>>
> > >>> with of_dma_configure(), which has the chance to configure more than
> > >>> just those three, as the dma API might look into different aspects:
> > >>>
> > >>> - iommu specific configuration
> > >>> - cache coherency information
> > >>> - bus type
> > >>> - dma offset
> > >>> - dma_map_ops pointer
> > >>>
> > >>> We try to handle everything in of_dma_configure() at configuration
> > >>> time, and that would be the place to add anything else that we might
> > >>> need in the future.
> > >>>
> > >>
> > >> Yes, I agree with you, but just like Felipe mentioned, we also need to
> > >> consider PCI device, can we do something like gpiod_get_index does? Are
> > >> there any similar APIs like of_dma_configure for ACPI?
> > >
> > > Not yet, but Lorenzo has one in progress[1], primarily for the sake of
> > > abstracting away the IOMMU configuration.
> > >
> > > Robin.
> > >
> > > [1]:http://www.mail-archive.com/linux-kernel@vger.kernel.org/msg1209911.html
> >
> > not exported for drivers to use. If Lorenzo is trying to making a
> > matching API for ACPI systems, then it needs to follow what
> > of_dma_configure() is doing, and add an EXPORT_SYMBOL_GPL()
>
> That's easy enough, not sure I understand though why
> of_dma_deconfigure() is not exported then. The second question mark
> is about the dma-ranges equivalent in ACPI world; the _DMA method
> seems to be the exact equivalent but to the best of my knowledge
> it is ignored by the kernel, to really have an of_dma_configure()
> equivalent that's really necessary, unless we want to resort to
> arch specific methods (is that what x86 is currently doing ?) to
> retrieve/build the dma masks.
Please see the follow-up emails after my proposed patch: if we add
a pointer to the device that firmware knows about in the USB core layer,
there is no longer a problem to be solved and the DMA operations will
do the right thing.
Arnd
next prev parent reply other threads:[~2016-09-14 21:51 UTC|newest]
Thread overview: 91+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-04-25 19:21 [PATCH] usb: dwc3: host: inherit dma configuration from parent dev Grygorii Strashko
2016-04-26 6:17 ` Felipe Balbi
2016-04-26 8:14 ` Grygorii Strashko
2016-04-27 5:41 ` Felipe Balbi
2016-04-27 11:55 ` Grygorii Strashko
2016-04-27 13:59 ` Catalin Marinas
2016-04-27 14:11 ` Arnd Bergmann
2016-04-27 15:50 ` Catalin Marinas
2016-04-27 16:04 ` Arnd Bergmann
2016-04-27 16:53 ` Felipe Balbi
2016-04-27 17:42 ` Arnd Bergmann
2016-04-27 17:59 ` Alan Stern
2016-04-27 18:08 ` Arnd Bergmann
2016-04-27 20:05 ` Felipe Balbi
2016-04-27 21:05 ` Arnd Bergmann
2016-04-28 6:37 ` Felipe Balbi
2016-04-28 14:16 ` Russell King - ARM Linux
2016-04-28 14:23 ` Arnd Bergmann
2016-04-28 14:27 ` Felipe Balbi
2016-09-01 22:14 ` Leo Li
2016-09-02 10:43 ` Arnd Bergmann
2016-09-02 10:47 ` Russell King - ARM Linux
2016-09-02 11:08 ` Felipe Balbi
2016-09-02 14:11 ` Felipe Balbi
2016-09-02 14:21 ` Alan Stern
2016-09-02 15:51 ` Arnd Bergmann
2016-09-07 7:17 ` Roger Quadros
2016-09-07 8:29 ` Arnd Bergmann
2016-09-07 13:04 ` Roger Quadros
2016-09-07 14:38 ` Arnd Bergmann
2016-09-02 16:23 ` Grygorii Strashko
2016-09-02 10:53 ` Felipe Balbi
2016-09-02 11:55 ` Robin Murphy
2016-09-02 12:56 ` Felipe Balbi
2016-09-02 13:10 ` Arnd Bergmann
2016-09-02 22:16 ` Leo Li
2016-09-05 15:39 ` Arnd Bergmann
2016-09-06 6:35 ` Peter Chen
2016-09-06 6:40 ` Felipe Balbi
2016-09-06 10:46 ` Arnd Bergmann
2016-09-06 10:50 ` Felipe Balbi
2016-09-06 13:27 ` Arnd Bergmann
2016-09-07 6:51 ` Felipe Balbi
2016-09-07 7:44 ` Peter Chen
2016-09-07 8:52 ` Arnd Bergmann
2016-09-07 9:29 ` Peter Chen
2016-09-07 9:35 ` Russell King - ARM Linux
2016-09-07 10:18 ` Felipe Balbi
2016-09-06 10:38 ` Arnd Bergmann
2016-09-07 6:33 ` Peter Chen
2016-09-07 8:48 ` Arnd Bergmann
2016-09-07 9:55 ` Peter Chen
2016-09-07 10:33 ` Robin Murphy
2016-09-07 10:47 ` Felipe Balbi
2016-09-14 16:31 ` Lorenzo Pieralisi
2016-09-14 21:50 ` Arnd Bergmann [this message]
2016-09-07 10:24 ` Felipe Balbi
2016-09-07 15:24 ` Arnd Bergmann
2016-09-07 16:08 ` Alan Stern
2016-09-07 19:45 ` Arnd Bergmann
2016-09-08 1:15 ` Peter Chen
2016-09-08 8:02 ` Arnd Bergmann
2016-09-08 8:03 ` Felipe Balbi
2016-09-08 8:26 ` Arnd Bergmann
2016-09-08 8:29 ` Felipe Balbi
2016-09-08 8:45 ` Arnd Bergmann
2016-09-08 9:43 ` Felipe Balbi
2016-09-08 10:17 ` Arnd Bergmann
2016-09-08 11:00 ` Felipe Balbi
2016-09-08 11:11 ` Arnd Bergmann
2016-09-08 11:20 ` Felipe Balbi
2016-09-08 11:39 ` Arnd Bergmann
2016-09-08 11:52 ` Felipe Balbi
2016-09-08 12:46 ` Arnd Bergmann
2016-09-08 12:02 ` Grygorii Strashko
2016-09-08 12:14 ` Arnd Bergmann
2016-09-08 12:28 ` Peter Chen
2016-09-08 12:52 ` Arnd Bergmann
2016-09-09 1:37 ` Peter Chen
2016-09-08 12:59 ` Grygorii Strashko
2016-09-09 1:52 ` Peter Chen
2016-09-21 11:06 ` Sriram Dash
2016-09-21 11:31 ` Arnd Bergmann
2016-09-21 11:43 ` Sriram Dash
2016-09-21 12:48 ` Arnd Bergmann
2016-09-22 5:02 ` Sriram Dash
2016-10-07 22:46 ` Leo Li
2016-09-21 17:14 ` [PATCH] usb: xhci: Fix the patch inherit dma configuration from kbuild test robot
2016-04-27 20:57 ` [PATCH] usb: dwc3: host: inherit dma configuration from parent dev Felipe Balbi
2016-04-27 14:14 ` Grygorii Strashko
2016-05-05 17:07 ` Brian Norris
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