Re: [PATCH] usb: dwc3: host: inherit dma configuration from parent dev

Alan Stern
2016-09-07T16:08:36Z

On Wed, 7 Sep 2016, Arnd Bergmann wrote:

> However, to summarize the discussion so far, I agree that
> of_dma_configure() is not the solution to these problems, and I think
> we can do much better:
>
> Splitting the usb_bus->controller field into the Linux-internal device
> (used for the sysfs hierarchy, for printks and for power management)
> and a new pointer (used for DMA, DT enumeration and phy lookup) probably
> covers all that we really need.
>
> I've prototyped it below, with the dwc3, xhci and chipidea changes
> together with the core changes. I've surely made mistakes there and
> don't expect it to work out of the box, but this should give an
> idea of how I think this can all be solved in the least invasive
> way.
>
> I noticed that the gadget interface already has a way to handle the
> DMA allocation by device, so I added that in as well.
>
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
>
> drivers/usb/chipidea/core.c | 4 ----
> drivers/usb/chipidea/host.c | 3 ++-
> drivers/usb/chipidea/udc.c | 8 ++++----
> drivers/usb/core/buffer.c | 12 ++++++------
> drivers/usb/core/hcd.c | 48 +++++++++++++++++++++++++++++-------------------
> drivers/usb/core/usb.c | 16 ++++++++--------
> drivers/usb/dwc3/core.c | 28 +++++++++++++++-------------
> drivers/usb/dwc3/core.h | 1 +
> drivers/usb/dwc3/dwc3-exynos.c | 10 ----------
> drivers/usb/dwc3/dwc3-st.c | 1 -
> drivers/usb/dwc3/ep0.c | 8 ++++----
> drivers/usb/dwc3/gadget.c | 34 +++++++++++++++++-----------------
> drivers/usb/dwc3/host.c | 13 ++++---------
> drivers/usb/host/ehci-fsl.c | 4 ++--

How did this driver end up in the patch?

> drivers/usb/host/xhci-plat.c | 32 +++++++++++++++++++++++++-------
> include/linux/usb.h | 1 +
> include/linux/usb/hcd.h | 3 +++

> diff --git a/drivers/usb/host/ehci-fsl.c b/drivers/usb/host/ehci-fsl.c
> index 9f5ffb629973..b2419950221f 100644
> --- a/drivers/usb/host/ehci-fsl.c
> +++ b/drivers/usb/host/ehci-fsl.c
> @@ -96,8 +96,8 @@ static int fsl_ehci_drv_probe(struct platform_device *pdev)
> }
> irq = res->start;
>
> - hcd = usb_create_hcd(&fsl_ehci_hc_driver, &pdev->dev,
> - dev_name(&pdev->dev));
> + hcd = __usb_create_hcd(&fsl_ehci_hc_driver, &pdev->dev.parent,
> + &pdev->dev, dev_name(&pdev->dev), NULL);

Based on the

if (of_device_is_compatible(dev->parent->of_node,
"fsl,mpc5121-usb2-dr")) {

lines in the driver?

> if (!hcd) {
> retval = -ENOMEM;
> goto err1;

Alan Stern