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

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Message-ID: <87r16v9uo2.fsf@miraculix.mork.no>
Date:   Mon, 21 Mar 2022 16:45:01 +0100
From:   Bjørn Mork <bjorn@...k.no>
To:     Daehwan Jung <dh10.jung@...sung.com>
Cc:     Mathias Nyman <mathias.nyman@...el.com>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        linux-usb@...r.kernel.org, linux-kernel@...r.kernel.org,
        Howard Yen <howardyen@...gle.com>,
        Jack Pham <jackp@...eaurora.org>,
        Puma Hsu <pumahsu@...gle.com>,
        "J . Avila" <elavila@...gle.com>, sc.suh@...sung.com
Subject: Re: [PATCH v3 4/4] usb: host: add xhci-exynos driver

Daehwan Jung <dh10.jung@...sung.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@...sung.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