Re: [PATCH v3 4/4] usb: host: add xhci-exynos driver

Jung Daehwan
2022-03-23T05:19:11Z

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On Tue, Mar 22, 2022 at 06:16:58PM +0100, Krzysztof Kozlowski wrote:
> On 21/03/2022 09:59, Daehwan Jung wrote:
> > This driver supports USB Audio offload with Co-processor.
> > It only cares DCBAA, Device Context, Transfer Ring, Event Ring, and ERST.
> > They are allocated on specific address with xhci hooks.
> > Co-processor could use them directly without xhci driver after then.
> >
> > Signed-off-by: Daehwan Jung <dh10.jung@samsung.com>
> > ---
> > drivers/usb/host/Kconfig | 9 +
> > drivers/usb/host/Makefile | 1 +
> > drivers/usb/host/xhci-exynos.c | 982 +++++++++++++++++++++++++++++++++
> > drivers/usb/host/xhci-exynos.h | 63 +++
> > 4 files changed, 1055 insertions(+)
> > create mode 100644 drivers/usb/host/xhci-exynos.c
> > create mode 100644 drivers/usb/host/xhci-exynos.h
> >
> > diff --git a/drivers/usb/host/Kconfig b/drivers/usb/host/Kconfig
> > index 57ca5f97a3dc..850e6b71fac5 100644
> > --- a/drivers/usb/host/Kconfig
> > +++ b/drivers/usb/host/Kconfig
> > @@ -783,3 +783,12 @@ config USB_XEN_HCD
> > by the Xen host (usually Dom0).
> > Only needed if the kernel is running in a Xen guest and generic
> > access to a USB device is needed.
> > +
> > +config USB_XHCI_EXYNOS
> > + tristate "XHCI support for Samsung Exynos SoC Series"
> > + depends on ARCH_EXYNOS || COMPILE_TEST
> > + help
> > + Enable support for the Samsung Exynos SOC's on-chip XHCI
> > + controller.
> > +
> > + If unsure, say N.
> > diff --git a/drivers/usb/host/Makefile b/drivers/usb/host/Makefile
> > index 2948983618fb..300f22b6eb1b 100644
> > --- a/drivers/usb/host/Makefile
> > +++ b/drivers/usb/host/Makefile
> > @@ -86,3 +86,4 @@ obj-$(CONFIG_USB_HCD_SSB) += ssb-hcd.o
> > obj-$(CONFIG_USB_FOTG210_HCD) += fotg210-hcd.o
> > obj-$(CONFIG_USB_MAX3421_HCD) += max3421-hcd.o
> > obj-$(CONFIG_USB_XEN_HCD) += xen-hcd.o
> > +obj-$(CONFIG_USB_XHCI_EXYNOS) += xhci-exynos.o
> > diff --git a/drivers/usb/host/xhci-exynos.c b/drivers/usb/host/xhci-exynos.c
> > new file mode 100644
> > index 000000000000..19ee21f1d024
> > --- /dev/null
> > +++ b/drivers/usb/host/xhci-exynos.c
> > @@ -0,0 +1,982 @@
> > +// SPDX-License-Identifier: GPL-2.0
> > +/*
> > + * xhci-exynos.c - xHCI host controller driver platform Bus Glue for Exynos.
> > + *
> > + * Copyright (C) 2022 Samsung Electronics Incorporated - http://www.samsung.com
> > + * Author: Daehwan Jung <dh10.jung@samsung.com>
> > + *
> > + * A lot of code borrowed from the Linux xHCI driver.
> > + */
> > +#include <linux/clk.h>
> > +#include <linux/dma-mapping.h>
> > +#include <linux/module.h>
> > +#include <linux/pci.h>
> > +#include <linux/of.h>
> > +#include <linux/of_device.h>
> > +#include <linux/platform_device.h>
> > +#include <linux/usb/phy.h>
> > +#include <linux/slab.h>
> > +#include <linux/acpi.h>
> > +#include <linux/usb/of.h>
> > +
> > +#include "xhci.h"
> > +#include "xhci-plat.h"
> > +#include "xhci-mvebu.h"
> > +#include "xhci-rcar.h"
>
> Could you explain why do you need RCAR and Marvell code in Exynos? Is it
> even a real driver here? On what platforms this can be tested? Where are
> the bindings?

2 headers you said are not needed. I'm going to remove it on next
submission. I tested on Exynos platform and it's real driver. I haven't
made bindings.

>
>
> (...)
>
>
> > +static const struct of_device_id usb_xhci_of_match[] = {
> > + {
> > + .compatible = "generic-xhci",
> > + }, {
> > + .compatible = "xhci-platform",
> > + },
> > + {},
> > +};
> > +MODULE_DEVICE_TABLE(of, usb_xhci_of_match);
> > +#endif
>
> No, this not generic-xhci but Exynos driver. This does not make any sense.
>

I agree with you and I'm going to remove it.

>
> Best regards,
> Krzysztof
>

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