From: Grygorii Strashko <grygorii.strashko@ti.com>
To: Felipe Balbi <balbi@kernel.org>, Arnd Bergmann <arnd@arndb.de>
Cc: Peter Chen <hzpeterchen@gmail.com>, Leo Li <pku.leo@gmail.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>,
Alan Stern <stern@rowland.harvard.edu>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
"linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>
Subject: Re: [PATCH] usb: dwc3: host: inherit dma configuration from parent dev
Date: Thu, 8 Sep 2016 15:02:56 +0300 [thread overview]
Message-ID: <01a5728b-9ea7-3ccf-34e8-7602a654306b@ti.com> (raw)
In-Reply-To: <87d1keirlu.fsf@linux.intel.com>
On 09/08/2016 02:00 PM, Felipe Balbi wrote:
>
> Hi,
>
> Arnd Bergmann <arnd@arndb.de> writes:
>> On Thursday, September 8, 2016 12:43:06 PM CEST Felipe Balbi wrote:
>>> Arnd Bergmann <arnd@arndb.de> writes:
>>>> On Thursday, September 8, 2016 11:29:04 AM CEST Felipe Balbi wrote:
>>>>>> If we do that, we have to put child devices of the dwc3 devices into
>>>>>> the platform glue, and it also breaks those dwc3 devices that don't
>>>>>> have a parent driver.
>>>>>
>>>>> Well, this is easy to fix:
>>>>>
>>>>> if (dwc->dev->parent) {
>>>>> dwc->sysdev = dwc->dev->parent;
>>>>> } else {
>>>>> dev_info(dwc->dev, "Please provide a glue layer!\n");
>>>>> dwc->sysdev = dwc->dev;
>>>>> }
>>>>
>>>> I don't understand. Do you mean we should have an extra level of
>>>> stacking and splitting "static struct platform_driver dwc3_driver"
>>>> in two so instead of
>>>>
>>>> "qcom,dwc3" -> "snps,dwc3" (usb_bus.sysdev) -> "xhci" (usb_bus.dev)
>>>>
>>>> we do this?
>>>>
>>>> "qcom,dwc3" -> "snps,dwc3" (usb_bus.sysdev) -> "dwc3-glue" -> "xhci" (usb_bus.dev)
>>>
>>> no
>>>
>>> If we have a parent device, use that as sysdev, otherwise use self as
>>> sysdev.
>>
>> But there is often a parent device in DT, as the xhci device is
>> attached to some internal bus that gets turned into a platform_device
>> as well, so checking whether there is a parent will get the wrong
>> device node.
>
> oh, that makes things more interesting :-s
>
>>>> That sounds a bit clumsy for the sake of consistency with PCI.
>>>> The advantage is that xhci can always use the grandparent device
>>>> as sysdev whenever it isn't probed through PCI or firmware
>>>> itself, but the purpose of the dwc3-glue is otherwise questionable.
>>>>
>>>> How about adding a 'compatible="snps,dwc3-pci"' property for the dwc3
>>>> device when that is created from the PCI driver and checking for that
>>>> with the device property interface instead? If it's "snps,dwc3"
>>>> we use the device itself while for "snps,dwc3-pci", we use the parent?
>>>
>>> Any reason why we wouldn't use e.g. dwc3-omap.dev as sysdev?
>>
>> That would be incompatible with the USB binding, as the sysdev
>> is assumed to be a USB host controller with #address-cells=<1>
>> and #size-cells=<0> in order to hold the child devices, for
>> example:
>>
>> / {
>> omap_dwc3_1: omap_dwc3_1@48880000 {
>> compatible = "ti,dwc3";
>> #address-cells = <1>;
>> #size-cells = <1>;
>> ranges;
>> usb1: usb@48890000 {
>> compatible = "snps,dwc3";
>> reg = <0x48890000 0x17000>;
>> #address-cells = <1>;
>> #size-cells = <0>;
>> interrupts = <GIC_SPI 71 IRQ_TYPE_LEVEL_HIGH>,
>> <GIC_SPI 71 IRQ_TYPE_LEVEL_HIGH>,
>> <GIC_SPI 72 IRQ_TYPE_LEVEL_HIGH>;
>> interrupt-names = "peripheral",
>> "host",
>> "otg";
>> phys = <&usb2_phy1>, <&usb3_phy1>;
>> phy-names = "usb2-phy", "usb3-phy";
>>
>> hub@1 {
>> compatible = "usb5e3,608";
>> reg = <1>;
>> #address-cells = <1>;
>> #size-cells = <0>;
>>
>> ethernet@1 {
>> compatible = "usb424,ec00";
>> mac-address = [00 11 22 33 44 55];
>> reg = <1>;
>> };
>> };
>> };
>> };
>>
>> It's also the node that contains the "phys" properties and
>> presumably other properties like "otg-rev", "maximum-speed"
>> etc.
>>
>> If we make the sysdev point to the parent, then we can no longer
>> look up those properties and child devices from the USB core code
>> by looking at "sysdev->of_node".
>
> this also makes things more interesting. I can't of anything other than
> having some type of flag passed via e.g. device_properties by dwc3-pci.c
> :-s
>
> It's quite a hack, though. I still think that inheriting DMA (or
> manually initializing a child with parent's DMA bits and pieces) is the
> best way to go. So we're back to of_dma_configure() and
> acpi_dma_configure(), right?
>
> But this needs to be done before dwc3_probe() executes. For dwc3-pci
> that's easy, but for DT devices, seems like it should be in of
> core. Below is, clearly, not enough but should show the idea:
>
> diff --git a/drivers/of/device.c b/drivers/of/device.c
> index fd5cfad7c403..a54610198946 100644
> --- a/drivers/of/device.c
> +++ b/drivers/of/device.c
> @@ -94,8 +94,12 @@ void of_dma_configure(struct device *dev, struct device_node *np)
> * Set default coherent_dma_mask to 32 bit. Drivers are expected to
> * setup the correct supported mask.
> */
> - if (!dev->coherent_dma_mask)
> - dev->coherent_dma_mask = DMA_BIT_MASK(32);
> + if (!dev->coherent_dma_mask) {
> + if (!dev->parent->coherent_dma_mask)
> + dev->coherent_dma_mask = DMA_BIT_MASK(32);
> + else
> + dev->coherent_dma_mask = dev->parent->coherent_dma_mask;
> + }
>
> /*
> * Set it to coherent_dma_mask by default if the architecture
>
>
I'd like to clarify few points here:
- the default dma_mask = DMA_BIT_MASK(32); assigned here to keep
backward compatibility with existing DT files at the moment when
of_dma_configure() has been introduced and it satisfies most of the cases
- if HW require specific DMA configuration then "dma-ranges" property have to be
defined and of_dma_configure() will take care of it just few lines down.
including parent-child case - as it will try to find "dma-ranes" prop in parent node
when called for child dev.
Personally, I think Arnd's approach should work, if the problem of selecting of proper
sysdev/dma_dev device will be solved.
Wouldn't it work if is_device_dma_capable() will be used?
For DT-case, the device DMA properties have to be configured from DT. So, now
there are 2 cases for dwc3:
1) dwc3-glue (of_dma)
|- dwc3 (of_dma)
|- xhci-plat (manual)
better to use dwc3-glue as sysdev, but can use dwc3 also
2) (arch/arm/boot/dts/ls1021a.dtsi)
|- dwc3 (of_dma)
|- xhci-plat (manual)
need to use dwc3 as sysdev
dwc3: probe()
if (!&pdev->dev->of_node)
legacy case - hard-code DMA props
dwc->sysdev = &pdev->dev;
else
dev = &pdev->dev;
do {
if (is_device_dma_capable(dev)) {
dwc->sysdev = dev;
break;
}
dev = dev->parent;
while (dev);
^this cycle can be limited in depth (2 for PCI)
if (!dwc->sysdev)
oops;
xhci_plat_probe:
do the same
Wouldn't above work for other cases PCI/ACPI?
--
regards,
-grygorii
next prev parent reply other threads:[~2016-09-08 12:04 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
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 [this message]
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
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=01a5728b-9ea7-3ccf-34e8-7602a654306b@ti.com \
--to=grygorii.strashko@ti.com \
--cc=arnd@arndb.de \
--cc=balbi@kernel.org \
--cc=catalin.marinas@arm.com \
--cc=david.fisher1@synopsys.com \
--cc=gregkh@linuxfoundation.org \
--cc=hzpeterchen@gmail.com \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-usb@vger.kernel.org \
--cc=linux@arm.linux.org.uk \
--cc=nsekhar@ti.com \
--cc=oss@buserror.net \
--cc=pku.leo@gmail.com \
--cc=stern@rowland.harvard.edu \
--cc=stuart.yoder@nxp.com \
--cc=tqnguyen@apm.com \
--cc=yoshihiro.shimoda.uh@renesas.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).