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

Bjørn Mork
2022-03-21T15:56:43Z

Daehwan Jung <dh10.jung@samsung.com> writes:

> +++ 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"

The xhci-plat.c file is Copyright (C) 2012 Texas Instruments Incorporated
You can't just steal it.

Besides, even if you could, this isn't about copying as much code as
posible from A to B. The point is to add as *little* code as possible
to support your hardware.

> +static int xhci_exynos_vendor_init(struct xhci_hcd *xhci)
> +{
> + /* TODO */
> + return 0;
> +}

And you didn't even add that?

> +static int xhci_exynos_wake_lock(struct xhci_hcd_exynos *xhci_exynos,
> + int is_main_hcd, int is_lock)
> +{
> + struct usb_hcd *hcd = xhci_exynos->hcd;
> + struct xhci_hcd *xhci = hcd_to_xhci(hcd);
> + struct wakeup_source *main_wakelock, *shared_wakelock;
> +
> + main_wakelock = xhci_exynos->main_wakelock;
> + shared_wakelock = xhci_exynos->shared_wakelock;

Are these fields initialized anywhere?

> +
> + if (xhci->xhc_state & XHCI_STATE_REMOVING)
> + return -ESHUTDOWN;
> +
> + if (is_lock) {

bool?

> + if (is_main_hcd)

another bool?

> + __pm_stay_awake(main_wakelock);
> + else
> + __pm_stay_awake(shared_wakelock);
> + } else {
> + if (is_main_hcd)
> + __pm_relax(main_wakelock);
> + else
> + __pm_relax(shared_wakelock);
> + }

Looks interesting. Are you signalling relax/wakeups events to the PM
core on device suspend/resume? Why?

> +static int xhci_exynos_address_device(struct usb_hcd *hcd, struct usb_device *udev)
> +{
> + struct xhci_hcd *xhci;
> + int ret;
> +
> + ret = xhci_address_device(hcd, udev);
> + xhci = hcd_to_xhci(hcd);
> +
> + return ret;
> +}

What's left here if we drop the unused parts?

> +#ifdef CONFIG_OF
> +static const struct xhci_plat_priv xhci_plat_marvell_armada = {
> + .init_quirk = xhci_mvebu_mbus_init_quirk,
> +};
> +
> +static const struct xhci_plat_priv xhci_plat_marvell_armada3700 = {
> + .plat_setup = xhci_mvebu_a3700_plat_setup,
> + .init_quirk = xhci_mvebu_a3700_init_quirk,
> +};

Right...

> +#ifdef CONFIG_ACPI
> +static const struct acpi_device_id usb_xhci_acpi_match[] = {
> + /* XHCI-compliant USB Controller */
> + { "PNP0D10", },
> + { }
> +};
> +MODULE_DEVICE_TABLE(acpi, usb_xhci_acpi_match);
> +#endif

Nice one

There's no need to copy me if you plan to resend any of this. I'm just
a drive-by reader here anyway, and I've seen enough.

Good luck!

Bjørn