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Date: Fri, 15 May 2020 15:07:54 +0200
From: Greg KH <gregkh@...uxfoundation.org>
To: Vladimir Stankovic <vladimir.stankovic@...playlink.com>
Cc: linux-kernel@...r.kernel.org, linux-usb@...r.kernel.org,
mausb-host-devel@...playlink.com
Subject: Re: [PATCH v6 3/8] usb: mausb_host: HCD initialization
On Fri, May 15, 2020 at 02:34:57PM +0200, Vladimir Stankovic wrote:
> --- /dev/null
> +++ b/drivers/usb/host/mausb/hcd.c
> @@ -0,0 +1,120 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Copyright (c) 2019 - 2020 DisplayLink (UK) Ltd.
> + */
> +#include "hcd.h"
> +
> +#include "utils.h"
> +
> +static int mausb_bus_match(struct device *dev, struct device_driver *drv);
> +
> +static const struct file_operations mausb_fops;
> +
> +static unsigned int major;
> +static unsigned int minor = 1;
> +static dev_t devt;
> +static struct device *device;
> +
> +struct mausb_hcd *mhcd;
> +static struct class *mausb_class;
> +static struct bus_type mausb_bus_type = {
> + .name = DEVICE_NAME,
> + .match = mausb_bus_match,
> +};
A static bus type??? For a single driver?
> +
> +static struct device_driver mausb_driver = {
> + .name = DEVICE_NAME,
> + .bus = &mausb_bus_type,
> + .owner = THIS_MODULE,
> +};
Wait, what??? A static "raw" struct device_driver? Why???
> +
> +static void mausb_remove(void)
> +{
> + struct usb_hcd *hcd, *shared_hcd;
> +
> + hcd = mhcd->hcd_hs_ctx->hcd;
> + shared_hcd = mhcd->hcd_ss_ctx->hcd;
> +
> + if (shared_hcd) {
> + usb_remove_hcd(shared_hcd);
> + usb_put_hcd(shared_hcd);
> + mhcd->hcd_ss_ctx = NULL;
> + }
> +
> + usb_remove_hcd(hcd);
> + usb_put_hcd(hcd);
> + mhcd->hcd_hs_ctx = NULL;
> +}
> +
> +static int mausb_bus_match(struct device *dev, struct device_driver *drv)
> +{
> + if (strncmp(dev->bus->name, drv->name, strlen(drv->name)))
> + return 0;
> + else
> + return 1;
> +}
> +
> +int mausb_init_hcd(void)
> +{
> + int retval = register_chrdev(0, DEVICE_NAME, &mausb_fops);
> +
> + if (retval < 0)
> + return retval;
> +
> + major = (unsigned int)retval;
> + retval = bus_register(&mausb_bus_type);
> + if (retval)
> + goto bus_register_error;
> +
> + mausb_class = class_create(THIS_MODULE, CLASS_NAME);
> + if (IS_ERR(mausb_class)) {
> + retval = (int)PTR_ERR(mausb_class);
> + goto class_error;
> + }
> +
> + retval = driver_register(&mausb_driver);
> + if (retval)
> + goto driver_register_error;
> +
> + mhcd = kzalloc(sizeof(*mhcd), GFP_ATOMIC);
> + if (!mhcd) {
> + retval = -ENOMEM;
> + goto mausb_hcd_alloc_failed;
> + }
> +
> + devt = MKDEV(major, minor);
> + device = device_create(mausb_class, NULL, devt, mhcd, DEVICE_NAME);
> + if (IS_ERR(device)) {
> + retval = (int)IS_ERR(device);
> + goto device_create_error;
> + }
> +
> + device->driver = &mausb_driver;
Why? What is this device going to do? What do you need it for?
> +
> + return retval;
> +device_create_error:
> + kfree(mhcd);
> + mhcd = NULL;
> +mausb_hcd_alloc_failed:
> + driver_unregister(&mausb_driver);
> +driver_register_error:
> + class_destroy(mausb_class);
> +class_error:
> + bus_unregister(&mausb_bus_type);
> +bus_register_error:
> + unregister_chrdev(major, DEVICE_NAME);
I thought you were using the misc device, what are you doing with a
class and chardev? Why is that still here?
> +
> + return retval;
> +}
> +
> +void mausb_deinit_hcd(void)
> +{
> + if (mhcd) {
> + mausb_remove();
> + device_destroy(mausb_class, devt);
> + driver_unregister(&mausb_driver);
> + class_destroy(mausb_class);
> + bus_unregister(&mausb_bus_type);
> + unregister_chrdev(major, DEVICE_NAME);
> + }
> +}
> diff --git a/drivers/usb/host/mausb/hcd.h b/drivers/usb/host/mausb/hcd.h
> new file mode 100644
> index 000000000000..e2374af67663
> --- /dev/null
> +++ b/drivers/usb/host/mausb/hcd.h
> @@ -0,0 +1,65 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +/*
> + * Copyright (c) 2019 - 2020 DisplayLink (UK) Ltd.
> + */
> +#ifndef __MAUSB_HCD_H__
> +#define __MAUSB_HCD_H__
> +
> +#include <linux/slab.h>
> +#include <linux/usb.h>
> +#include <linux/usb/hcd.h>
> +
> +#define DEVICE_NAME "mausb_host_hcd"
> +#define CLASS_NAME "mausb"
> +
> +#define NUMBER_OF_PORTS 15
Why this max?
> +
> +#define MAX_USB_DEVICE_DEPTH 6
Where does this max come from?
> +
> +#define RESPONSE_TIMEOUT 5000
Units?
> +
> +#define MAUSB_PORT_20_STATUS_LOW_SPEED 0x0200
> +#define MAUSB_PORT_20_STATUS_HIGH_SPEED 0x0400
Device ids? Something else?
If something else, use BIT()?
> +
> +enum mausb_device_type {
> + USBDEVICE = 0,
> + USB20HUB = 1,
> + USB30HUB = 2
Trailing , please
> +};
> +
> +enum mausb_device_speed {
> + LOW_SPEED = 0,
> + FULL_SPEED = 1,
> + HIGH_SPEED = 2,
> + SUPER_SPEED = 3,
> + SUPER_SPEED_PLUS = 4
, please.
> +};
Where do these values come from?
> +
> +struct mausb_hcd {
> + spinlock_t lock; /* Protect HCD during URB processing */
> + struct device *pdev;
> + u16 connected_ports;
Why u16?
> +
> + struct rb_root mausb_urbs;
> + struct hub_ctx *hcd_ss_ctx;
> + struct hub_ctx *hcd_hs_ctx;
> + struct notifier_block power_state_listener;
> +};
> +
> +struct mausb_dev {
> + u32 port_status;
> + struct rb_root usb_devices;
> + u8 dev_speed;
> + void *ma_dev;
> +};
> +
> +struct hub_ctx {
> + struct mausb_hcd *mhcd;
> + struct usb_hcd *hcd;
> + struct mausb_dev ma_devs[NUMBER_OF_PORTS];
> +};
> +
> +int mausb_init_hcd(void);
> +void mausb_deinit_hcd(void);
> +
> +#endif /* __MAUSB_HCD_H__ */
> diff --git a/drivers/usb/host/mausb/mausb_core.c b/drivers/usb/host/mausb/mausb_core.c
> index 44f76a1b74de..485f241d2b4c 100644
> --- a/drivers/usb/host/mausb/mausb_core.c
> +++ b/drivers/usb/host/mausb/mausb_core.c
> @@ -4,6 +4,7 @@
> */
> #include <linux/module.h>
>
> +#include "hcd.h"
> #include "utils.h"
>
> MODULE_LICENSE("GPL");
> @@ -11,12 +12,27 @@ MODULE_AUTHOR("DisplayLink (UK) Ltd.");
>
> static int mausb_host_init(void)
> {
> - return mausb_host_dev_register();
> + int status = mausb_host_dev_register();
> +
> + if (status < 0)
> + goto exit;
> +
> + status = mausb_init_hcd();
> + if (status < 0)
> + goto cleanup_dev;
> +
> + return 0;
> +
> +cleanup_dev:
> + mausb_host_dev_deregister();
> +exit:
> + return status;
> }
>
> static void mausb_host_exit(void)
> {
> dev_info(mausb_host_dev.this_device, "Module unloading started...");
This is debugging statements, please remove. If a driver works
properly, it does not print anything out.
Especially as you never give the user the chance to see if module
unloading ever finished :)
thanks,
greg k-h
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