[v5] watchdog: add driver for StreamLabs USB watchdog device

Message ID	20220725030605.1808710-1-klimov.linux@gmail.com
State	Superseded
Headers	show Return-Path: <linux-watchdog-owner@kernel.org> From: Alexey Klimov <klimov.linux@gmail.com> To: linux-watchdog@vger.kernel.org Cc: wim@linux-watchdog.org, linux@roeck-us.net, oneukum@suse.com, linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org, atishp@rivosinc.com, atishp@atishpatra.org, yury.norov@gmail.com, aklimov@redhat.com, atomlin@redhat.com, klimov.linux@gmail.com Subject: [PATCH v5] watchdog: add driver for StreamLabs USB watchdog device Date: Mon, 25 Jul 2022 04:06:05 +0100 Message-Id: <20220725030605.1808710-1-klimov.linux@gmail.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk
Series	[v5] watchdog: add driver for StreamLabs USB watchdog device \| expand [v5] watchdog: add driver for StreamLabs USB watchdog device

diff --git a/MAINTAINERS b/MAINTAINERS index 64379c699903..fb31c1823043 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -19190,6 +19190,12 @@ W: http://www.stlinux.com F: Documentation/networking/device_drivers/ethernet/stmicro/ F: drivers/net/ethernet/stmicro/stmmac/ +STREAMLABS USB WATCHDOG DRIVER +M: Alexey Klimov <klimov.linux@gmail.com> +L: linux-watchdog@vger.kernel.org +S: Maintained +F: drivers/watchdog/streamlabs_wdt.c + SUN3/3X M: Sam Creasey <sammy@sammy.net> S: Maintained diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig index 32fd37698932..64b7f947b196 100644 --- a/drivers/watchdog/Kconfig +++ b/drivers/watchdog/Kconfig @@ -2171,6 +2171,21 @@ config USBPCWATCHDOG Most people will say N. +config USB_STREAMLABS_WATCHDOG + tristate "StreamLabs USB watchdog driver" + depends on USB + help + This is the driver for the USB Watchdog dongle from StreamLabs. + If you correctly connect reset pins to motherboard Reset pin and + to Reset button then this device will simply watch your kernel to make + sure it doesn't freeze, and if it does, it reboots your computer + after a certain amount of time. + + To compile this driver as a module, choose M here: the + module will be called streamlabs_wdt. + + Most people will say N. Say yes or M if you want to use such usb device. + config KEEMBAY_WATCHDOG tristate "Intel Keem Bay SoC non-secure watchdog" depends on ARCH_KEEMBAY || (ARM64 && COMPILE_TEST) diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile index c324e9d820e9..2d601da9b5bd 100644 --- a/drivers/watchdog/Makefile +++ b/drivers/watchdog/Makefile @@ -33,6 +33,7 @@ obj-$(CONFIG_WDTPCI) += wdt_pci.o # USB-based Watchdog Cards obj-$(CONFIG_USBPCWATCHDOG) += pcwd_usb.o +obj-$(CONFIG_USB_STREAMLABS_WATCHDOG) += streamlabs_wdt.o # ALPHA Architecture diff --git a/drivers/watchdog/streamlabs_wdt.c b/drivers/watchdog/streamlabs_wdt.c new file mode 100644 index 000000000000..f1130fe5559c --- /dev/null +++ b/drivers/watchdog/streamlabs_wdt.c @@ -0,0 +1,360 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * StreamLabs USB Watchdog driver + * + * Copyright (c) 2016-2017,2022 Alexey Klimov <klimov.linux@gmail.com> + */ + +#include <linux/errno.h> +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/mutex.h> +#include <linux/slab.h> +#include <linux/types.h> +#include <linux/usb.h> +#include <linux/watchdog.h> +#include <asm/byteorder.h> + +/* + * USB Watchdog device from Streamlabs: + * https://www.stream-labs.com/products/devices/watch-dog/ + * + * USB commands have been reverse engineered using usbmon. + */ + +#define DRIVER_AUTHOR "Alexey Klimov <klimov.linux@gmail.com>" +#define DRIVER_DESC "StreamLabs USB watchdog driver" +#define DRIVER_NAME "usb_streamlabs_wdt" + +MODULE_AUTHOR(DRIVER_AUTHOR); +MODULE_DESCRIPTION(DRIVER_DESC); +MODULE_LICENSE("GPL"); + +#define USB_STREAMLABS_WATCHDOG_VENDOR 0x13c0 +#define USB_STREAMLABS_WATCHDOG_PRODUCT 0x0011 + +/* + * one buffer is used for communication, however transmitted message is only + * 32 bytes long + */ +#define BUFFER_TRANSFER_LENGTH 32 +#define BUFFER_LENGTH 64 +#define USB_TIMEOUT 350 + +#define STREAMLABS_CMD_START 0xaacc +#define STREAMLABS_CMD_STOP 0xbbff + +/* timeout values are taken from windows program */ +#define STREAMLABS_WDT_MIN_TIMEOUT 1 +#define STREAMLABS_WDT_MAX_TIMEOUT 46 + +struct streamlabs_wdt { + struct watchdog_device wdt_dev; + struct usb_interface *intf; + /* Serialises usb communication with a device */ + struct mutex lock; + __le16 *buffer; +}; + +static bool nowayout = WATCHDOG_NOWAYOUT; +module_param(nowayout, bool, 0); +MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" + __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); + +/* USB call wrappers to send and receive messages to/from the device. */ +static int usb_streamlabs_send_msg(struct usb_device *usbdev, __le16 *buf) +{ + int retval; + int size; + + retval = usb_interrupt_msg(usbdev, usb_sndintpipe(usbdev, 0x02), + buf, BUFFER_TRANSFER_LENGTH, + &size, USB_TIMEOUT); + + if (size != BUFFER_TRANSFER_LENGTH) + return -EIO; + + return retval; +} + +static int usb_streamlabs_get_msg(struct usb_device *usbdev, __le16 *buf) +{ + int retval; + int size; + + retval = usb_interrupt_msg(usbdev, usb_rcvintpipe(usbdev, 0x81), + buf, BUFFER_LENGTH, + &size, USB_TIMEOUT); + + if (size != BUFFER_LENGTH) + return -EIO; + + return retval; +} + +/* + * This function is used to check if watchdog timeout in the received buffer + * matches the timeout passed from watchdog subsystem. + */ +static int usb_streamlabs_wdt_check_timeout(__le16 *buf, unsigned long timeout) +{ + if (buf[3] != cpu_to_le16(timeout)) + return -EPROTO; + + return 0; +} + +static int usb_streamlabs_wdt_check_response(u8 *buf) +{ + /* + * If watchdog device understood the command it will acknowledge + * with values 1,2,3,4 at indexes 10, 11, 12, 13 in response message + * when response treated as 8bit message. + */ + if (buf[10] != 1 || buf[11] != 2 || buf[12] != 3 || buf[13] != 4) + return -EPROTO; + + return 0; +} + +/* + * This function is used to check if watchdog command in the received buffer + * matches the command passed to the device. + */ +static int usb_streamlabs_wdt_check_command(__le16 *buf, u16 cmd) +{ + if (buf[0] != cpu_to_le16(cmd)) + return -EPROTO; + + return 0; +} + +static int usb_streamlabs_wdt_validate_response(__le16 *buf, u16 cmd, + unsigned long timeout_msec) +{ + int retval; + + retval = usb_streamlabs_wdt_check_response((u8 *)buf); + if (retval) + return retval; + + retval = usb_streamlabs_wdt_check_command(buf, cmd); + if (retval) + return retval; + + retval = usb_streamlabs_wdt_check_timeout(buf, timeout_msec); + return retval; +} + +static void usb_streamlabs_wdt_prepare_buf(__le16 *buf, u16 cmd, + unsigned long timeout_msec) +{ + /* + * remaining elements expected to be zero everytime during + * communication + */ + buf[0] = cpu_to_le16(cmd); + buf[1] = cpu_to_le16(0x8000); + buf[3] = cpu_to_le16(timeout_msec); + buf[5] = 0x0; + buf[6] = 0x0; +} + +static int __usb_streamlabs_wdt_cmd(struct streamlabs_wdt *wdt, u16 cmd) +{ + struct usb_device *usbdev; + unsigned long timeout_msec; + /* how many times to re-try getting the state of the device */ + unsigned int retry_counter = 10; + int retval; + + if (unlikely(!wdt->intf)) + return -ENODEV; + + usbdev = interface_to_usbdev(wdt->intf); + timeout_msec = wdt->wdt_dev.timeout * MSEC_PER_SEC; + + usb_streamlabs_wdt_prepare_buf(wdt->buffer, cmd, timeout_msec); + + /* send command to watchdog */ + retval = usb_streamlabs_send_msg(usbdev, wdt->buffer); + if (retval) + return retval; + + /* + * Transition from one state to another in this device + * doesn't happen immediately, especially stopping the device + * is not observed on the first reading of the response. + * Plus to avoid potentially stale response message in the device + * we keep reading the state of the device until we see: + * -- that device recognised the sent command; + * -- the received state (started or stopped) matches the state + * that was requested; + * -- the timeout passed matches the timeout value read from + * the device. + * Keep retrying 10 times and if watchdog device doesn't respond + * correctly as expected we bail out and return an error. + */ + do { + retval = usb_streamlabs_get_msg(usbdev, wdt->buffer); + if (retval) + break; + + retval = usb_streamlabs_wdt_validate_response(wdt->buffer, cmd, + timeout_msec); + } while (retval && retry_counter--); + + return retry_counter ? retval : -EIO; +} + +static int usb_streamlabs_wdt_cmd(struct streamlabs_wdt *streamlabs_wdt, u16 cmd) +{ + int retval; + + mutex_lock(&streamlabs_wdt->lock); + retval = __usb_streamlabs_wdt_cmd(streamlabs_wdt, cmd); + mutex_unlock(&streamlabs_wdt->lock); + + return retval; +} + +static int usb_streamlabs_wdt_start(struct watchdog_device *wdt_dev) +{ + struct streamlabs_wdt *streamlabs_wdt = watchdog_get_drvdata(wdt_dev); + + return usb_streamlabs_wdt_cmd(streamlabs_wdt, STREAMLABS_CMD_START); +} + +static int usb_streamlabs_wdt_stop(struct watchdog_device *wdt_dev) +{ + struct streamlabs_wdt *streamlabs_wdt = watchdog_get_drvdata(wdt_dev); + + return usb_streamlabs_wdt_cmd(streamlabs_wdt, STREAMLABS_CMD_STOP); +} + +static const struct watchdog_info streamlabs_wdt_ident = { + .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING, + .identity = DRIVER_NAME, +}; + +static const struct watchdog_ops usb_streamlabs_wdt_ops = { + .owner = THIS_MODULE, + .start = usb_streamlabs_wdt_start, + .stop = usb_streamlabs_wdt_stop, +}; + +static int usb_streamlabs_wdt_probe(struct usb_interface *intf, + const struct usb_device_id *id) +{ + struct usb_device *usbdev = interface_to_usbdev(intf); + struct streamlabs_wdt *streamlabs_wdt; + int retval; + + /* + * USB IDs of this device appear to be weird/unregistered. Hence, do + * an additional check on product and manufacturer. + * If there is similar device in the field with same values then + * there is stop command in probe() below that checks if the device + * behaves as a watchdog. + */ + if (!usbdev->product || !usbdev->manufacturer || + strncmp(usbdev->product, "USBkit", 6) || + strncmp(usbdev->manufacturer, "STREAM LABS", 11)) + return -ENODEV; + + streamlabs_wdt = devm_kzalloc(&intf->dev, sizeof(struct streamlabs_wdt), + GFP_KERNEL); + if (!streamlabs_wdt) + return -ENOMEM; + + streamlabs_wdt->buffer = devm_kzalloc(&intf->dev, BUFFER_LENGTH, + GFP_KERNEL); + if (!streamlabs_wdt->buffer) + return -ENOMEM; + + mutex_init(&streamlabs_wdt->lock); + + streamlabs_wdt->wdt_dev.info = &streamlabs_wdt_ident; + streamlabs_wdt->wdt_dev.ops = &usb_streamlabs_wdt_ops; + streamlabs_wdt->wdt_dev.timeout = STREAMLABS_WDT_MAX_TIMEOUT; + streamlabs_wdt->wdt_dev.max_timeout = STREAMLABS_WDT_MAX_TIMEOUT; + streamlabs_wdt->wdt_dev.min_timeout = STREAMLABS_WDT_MIN_TIMEOUT; + streamlabs_wdt->wdt_dev.parent = &intf->dev; + + streamlabs_wdt->intf = intf; + usb_set_intfdata(intf, &streamlabs_wdt->wdt_dev); + watchdog_set_drvdata(&streamlabs_wdt->wdt_dev, streamlabs_wdt); + watchdog_set_nowayout(&streamlabs_wdt->wdt_dev, nowayout); + + retval = usb_streamlabs_wdt_stop(&streamlabs_wdt->wdt_dev); + if (retval) + return -ENODEV; + + retval = devm_watchdog_register_device(&intf->dev, + &streamlabs_wdt->wdt_dev); + if (retval) { + dev_err(&intf->dev, "failed to register watchdog device\n"); + return retval; + } + + dev_info(&intf->dev, "StreamLabs USB watchdog driver loaded.\n"); + return 0; +} + +static int usb_streamlabs_wdt_suspend(struct usb_interface *intf, + pm_message_t message) +{ + struct streamlabs_wdt *streamlabs_wdt = usb_get_intfdata(intf); + + if (watchdog_active(&streamlabs_wdt->wdt_dev)) + return usb_streamlabs_wdt_stop(&streamlabs_wdt->wdt_dev); + + return 0; +} + +static int usb_streamlabs_wdt_resume(struct usb_interface *intf) +{ + struct streamlabs_wdt *streamlabs_wdt = usb_get_intfdata(intf); + + if (watchdog_active(&streamlabs_wdt->wdt_dev)) + return usb_streamlabs_wdt_start(&streamlabs_wdt->wdt_dev); + + return 0; +} + +static void usb_streamlabs_wdt_disconnect(struct usb_interface *intf) +{ + struct streamlabs_wdt *streamlabs_wdt = usb_get_intfdata(intf); + + mutex_lock(&streamlabs_wdt->lock); + /* + * If disconnect happens via sysfs or on rmmod, then try to stop + * the watchdog. In case of physical detachment of the device this call + * will fail but we continue. + */ + if (!nowayout) + __usb_streamlabs_wdt_cmd(streamlabs_wdt, STREAMLABS_CMD_STOP); + /* Stop sending (new) messages to the device */ + streamlabs_wdt->intf = NULL; + mutex_unlock(&streamlabs_wdt->lock); +} + +static const struct usb_device_id usb_streamlabs_wdt_device_table[] = { + { USB_DEVICE(USB_STREAMLABS_WATCHDOG_VENDOR, USB_STREAMLABS_WATCHDOG_PRODUCT) }, + { } /* Terminating entry */ +}; + +MODULE_DEVICE_TABLE(usb, usb_streamlabs_wdt_device_table); + +static struct usb_driver usb_streamlabs_wdt_driver = { + .name = DRIVER_NAME, + .probe = usb_streamlabs_wdt_probe, + .disconnect = usb_streamlabs_wdt_disconnect, + .suspend = usb_streamlabs_wdt_suspend, + .resume = usb_streamlabs_wdt_resume, + .reset_resume = usb_streamlabs_wdt_resume, + .id_table = usb_streamlabs_wdt_device_table, + .soft_unbind = 1, +}; + +module_usb_driver(usb_streamlabs_wdt_driver);

[v5] watchdog: add driver for StreamLabs USB watchdog device

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