From: balbi@kernel•org (Felipe Balbi)
To: linux-arm-kernel@lists•infradead.org
Subject: [PATCH] usb: dwc3: host: inherit dma configuration from parent dev
Date: Wed, 27 Apr 2016 23:05:42 +0300 [thread overview]
Message-ID: <8737q6stpl.fsf@ti.com> (raw)
In-Reply-To: <13248156.8VXoeOzRlg@wuerfel>
Hi,
Arnd Bergmann <arnd@arndb•de> writes:
> On Wednesday 27 April 2016 13:59:13 Alan Stern wrote:
>> On Wed, 27 Apr 2016, Arnd Bergmann wrote:
>>
>> > I've looked at the usb HCD code now and see this:
>> >
>> > struct usb_hcd *usb_create_shared_hcd(const struct hc_driver *driver,
>> > struct device *dev, const char *bus_name,
>> > struct usb_hcd *primary_hcd)
>> > {
>> > ...
>> > hcd->self.controller = dev;
>> > hcd->self.uses_dma = (dev->dma_mask != NULL);
>> > ...
>> > }
>> >
>> > What I think we need to do here is ensure that the device that gets
>> > passed here and assigned to hcd->self.controller is the actual DMA
>> > master device, i.e. the pci_device or platform_device that was created
>> > from outside of the xhci stack. This is after all the pointer that
>> > gets passed into all the dma_map_*/dma_sync_*/dma_alloc_*/...
>> > functions.
>>
>> It would be better to add a new field, since self.controller is also
>> used for lots of other purposes. Something like hcd->self.dma_dev.
>
> Ok, fair enough. I only took a brief look and all uses I found were
> either for the DMA mapping API or some printk logging.
I have a feeling you guys are not considering how the patch to implement
this will look like.
How are you expecting dwc3 to pass a pointer to the DMA device from
dwc3.ko to xhci-plat ? platform_data ? That's gonna be horrible :-)
Also, remember that the DMA device for dwc3 is not always
dwc3->dev->parent. It might be dwc3->dev itself. How are you expecting
us to figure that one out ?
I still think dma_inherit() (or something along those lines) is
necessary. Specially when you consider that, as I said previously,
that's pretty much what of_dma_configure() does.
Anyway, I'd really like to see a patch implementing this
hcd->self.dma_dev logic. Consider all the duplication with this
approach, btw. struct dwc3 will *also* need a dwc->dma_dev of its
own. Will that be passed to dwc3 as platform_data from glue layer ? What
about platforms which don't even use a glue layer ?
--
balbi
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next prev parent reply other threads:[~2016-04-27 20:05 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 [this message]
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
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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