On Tue, Jul 20, 2021 at 05:45:11PM +0200, Linus Walleij wrote:
> This rewrites the IXP4xx watchdog driver as follows:
>
> - Spawn the watchdog driver as a platform device from the timer
> driver. It's one device in the hardware, and the fact that
> Linux splits the handling into two different devices is
> a Linux pecularity, and thus it becomes a Linux pecularity
> to spawn a separate watchdog driver.
>
> - Spawn the watchdog driver from the timer driver at probe().
> This is well after the timer driver as actually registered and
> started and we know the register base is available.
>
> - Instead of looping back callbacks to the timer drivers for all
> watchdog calls, pass the register base to the watchdog driver
> and manage the registers there. The two drivers aren't even
> interested in the same register so the spinlock is totally
> surplus, delete it.
>
> - Replace pretty much all of the content in the watchdog driver
> with a simple, modern watchdog driver utilizing the watchdog
> core instead of registering its own misc device and ioctl()
> handling.
>
> - Drop module parameters as the same already exist in the
> watchdog core.
>
> What remains is a slim elegant (IMO) watchdog driver using the
> watchdog core, spawning from device tree or boardfile alike.
>
> Cc: Daniel Lezcano <daniel.lezcano@xxxxxxxxxx>
> Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
> Signed-off-by: Linus Walleij <linus.walleij@xxxxxxxxxx>
> ---
> ChangeLog v1->v2:
> - Pull out dirty patches underneath this patch. Tested on a
> clean v5.14-rc1, sorry for the mess :(
> - Drop tick rate from the timer driver - was only used by this
> watchdog after all.
> - Retrieve a clock from the parent to get rate if possible,
> fallback to a default clock rate if not. Prepare and
> enable the clock.
> - Add a devres hook to disable the clock after use.
> - Drop pointless platfrom_set_drvdata()
> - Put a more technically correct print at end of probe.
> Merge path: I expect this to be merged through the watchdog
> subsystem once the timer maintainers are happy with the patch,
> so Daniel or tglx: once you approve the patch please ACK this.
> ---
> drivers/clocksource/timer-ixp4xx.c | 48 +++--
> drivers/watchdog/Kconfig | 3 +-
> drivers/watchdog/ixp4xx_wdt.c | 282 ++++++++++++-----------------
> 3 files changed, 157 insertions(+), 176 deletions(-)
>
> diff --git a/drivers/clocksource/timer-ixp4xx.c b/drivers/clocksource/timer-ixp4xx.c
> index 9396745e1c17..cbb184953510 100644
> --- a/drivers/clocksource/timer-ixp4xx.c
> +++ b/drivers/clocksource/timer-ixp4xx.c
> @@ -18,6 +18,7 @@
> #include <linux/delay.h>
> #include <linux/of_address.h>
> #include <linux/of_irq.h>
> +#include <linux/platform_device.h>
> /* Goes away with OF conversion */
> #include <linux/platform_data/timer-ixp4xx.h>
>
> @@ -29,9 +30,6 @@
> #define IXP4XX_OSRT1_OFFSET 0x08 /* Timer 1 Reload */
> #define IXP4XX_OST2_OFFSET 0x0C /* Timer 2 Timestamp */
> #define IXP4XX_OSRT2_OFFSET 0x10 /* Timer 2 Reload */
> -#define IXP4XX_OSWT_OFFSET 0x14 /* Watchdog Timer */
> -#define IXP4XX_OSWE_OFFSET 0x18 /* Watchdog Enable */
> -#define IXP4XX_OSWK_OFFSET 0x1C /* Watchdog Key */
> #define IXP4XX_OSST_OFFSET 0x20 /* Timer Status */
>
> /*
> @@ -45,17 +43,10 @@
> #define IXP4XX_OSST_TIMER_1_PEND 0x00000001
> #define IXP4XX_OSST_TIMER_2_PEND 0x00000002
> #define IXP4XX_OSST_TIMER_TS_PEND 0x00000004
> -#define IXP4XX_OSST_TIMER_WDOG_PEND 0x00000008
> -#define IXP4XX_OSST_TIMER_WARM_RESET 0x00000010
> -
> -#define IXP4XX_WDT_KEY 0x0000482E
> -#define IXP4XX_WDT_RESET_ENABLE 0x00000001
> -#define IXP4XX_WDT_IRQ_ENABLE 0x00000002
> -#define IXP4XX_WDT_COUNT_ENABLE 0x00000004
> +/* Remaining registers are for the watchdog and defined in the watchdog driver */
>
> struct ixp4xx_timer {
> void __iomem *base;
> - unsigned int tick_rate;
> u32 latch;
> struct clock_event_device clkevt;
> #ifdef CONFIG_ARM
> @@ -181,7 +172,6 @@ static __init int ixp4xx_timer_register(void __iomem *base,
> if (!tmr)
> return -ENOMEM;
> tmr->base = base;
> - tmr->tick_rate = timer_freq;
>
> /*
> * The timer register doesn't allow to specify the two least
> @@ -239,6 +229,40 @@ static __init int ixp4xx_timer_register(void __iomem *base,
> return 0;
> }
>
> +static struct platform_device ixp4xx_watchdog_device = {
> + .name = "ixp4xx-watchdog",
> + .id = -1,
> +};
> +
> +/*
> + * This probe gets called after the timer is already up and running. The main
> + * function on this platform is to spawn the watchdog device as a child.
> + */
> +static int ixp4xx_timer_probe(struct platform_device *pdev)
> +{
> + struct device *dev = &pdev->dev;
> +
> + /* Pass the base address as platform data and nothing else */
> + ixp4xx_watchdog_device.dev.platform_data = local_ixp4xx_timer->base;
> + ixp4xx_watchdog_device.dev.parent = dev;
> + return platform_device_register(&ixp4xx_watchdog_device);
> +}
> +
> +static const struct of_device_id ixp4xx_timer_dt_id[] = {
> + { .compatible = "intel,ixp4xx-timer", },
> + { /* sentinel */ },
> +};
> +
> +static struct platform_driver ixp4xx_timer_driver = {
> + .probe = ixp4xx_timer_probe,
> + .driver = {
> + .name = "ixp4xx-timer",
> + .of_match_table = ixp4xx_timer_dt_id,
> + .suppress_bind_attrs = true,
> + },
> +};
> +builtin_platform_driver(ixp4xx_timer_driver);
> +
> /**
> * ixp4xx_timer_setup() - Timer setup function to be called from boardfiles
> * @timerbase: physical base of timer block
> diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
> index 546dfc1e2349..33c97726144a 100644
> --- a/drivers/watchdog/Kconfig
> +++ b/drivers/watchdog/Kconfig
> @@ -486,7 +486,8 @@ config FTWDT010_WATCHDOG
>
> config IXP4XX_WATCHDOG
> tristate "IXP4xx Watchdog"
> - depends on ARCH_IXP4XX
> + depends on ARCH_IXP4XX || COMPILE_TEST
x86_64:allmodconfig:
drivers/watchdog/ixp4xx_wdt.c: In function ‘ixp4xx_wdt_probe’:
drivers/watchdog/ixp4xx_wdt.c:117:8: error: implicit declaration of function ‘read_cpuid_id’
You'd have to move the CPU check into the timer code to
be able to enable COMPILE_TEST.
> + select WATCHDOG_CORE
> help
> Say Y here if to include support for the watchdog timer
> in the Intel IXP4xx network processors. This driver can
> diff --git a/drivers/watchdog/ixp4xx_wdt.c b/drivers/watchdog/ixp4xx_wdt.c
> index aae29dcfaf11..9116ab097705 100644
> --- a/drivers/watchdog/ixp4xx_wdt.c
> +++ b/drivers/watchdog/ixp4xx_wdt.c
> @@ -1,220 +1,176 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> /*
> * drivers/char/watchdog/ixp4xx_wdt.c
> *
> * Watchdog driver for Intel IXP4xx network processors
> *
> * Author: Deepak Saxena <dsaxena@xxxxxxxxxxx>
> + * Author: Linus Walleij <linus.walleij@xxxxxxxxxx>
> *
> * Copyright 2004 (c) MontaVista, Software, Inc.
> * Based on sa1100 driver, Copyright (C) 2000 Oleg Drokin <green@xxxxxxxxxx>
> - *
> - * This file is licensed under the terms of the GNU General Public
> - * License version 2. This program is licensed "as is" without any
> - * warranty of any kind, whether express or implied.
> */
>
> -#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
> -
> #include <linux/module.h>
> -#include <linux/moduleparam.h>
> #include <linux/types.h>
> #include <linux/kernel.h>
> -#include <linux/fs.h>
> -#include <linux/miscdevice.h>
> -#include <linux/of.h>
> #include <linux/watchdog.h>
> #include <linux/init.h>
Is this still needed ?
> #include <linux/bitops.h>
I may be missing something, but I don't see any bit operations
in the driver.
> -#include <linux/uaccess.h>
> -#include <mach/hardware.h>
> +#include <linux/platform_device.h>
> +#include <linux/clk.h>
> +#include <linux/soc/ixp4xx/cpu.h>
> +
> +struct ixp4xx_wdt {
> + struct watchdog_device wdd;
> + void __iomem *base;
> + unsigned long rate;
> +};
>
> -static bool nowayout = WATCHDOG_NOWAYOUT;
> -static int heartbeat = 60; /* (secs) Default is 1 minute */
> -static unsigned long wdt_status;
> -static unsigned long boot_status;
> -static DEFINE_SPINLOCK(wdt_lock);
> +/* Fallback if we do not have a clock for this */
> +#define IXP4XX_TIMER_FREQ 66666000
Please use
#define<space>IXP4XX_TIMER_FREQ<tab>66666000
>
> -#define WDT_TICK_RATE (IXP4XX_PERIPHERAL_BUS_CLOCK * 1000000UL)
> +/* Registers after the timer registers */
> +#define IXP4XX_OSWT_OFFSET 0x14 /* Watchdog Timer */
> +#define IXP4XX_OSWE_OFFSET 0x18 /* Watchdog Enable */
> +#define IXP4XX_OSWK_OFFSET 0x1C /* Watchdog Key */
> +#define IXP4XX_OSST_OFFSET 0x20 /* Timer Status */
>
> -#define WDT_IN_USE 0
> -#define WDT_OK_TO_CLOSE 1
> +#define IXP4XX_OSST_TIMER_WDOG_PEND 0x00000008
> +#define IXP4XX_OSST_TIMER_WARM_RESET 0x00000010
> +#define IXP4XX_WDT_KEY 0x0000482E
> +#define IXP4XX_WDT_RESET_ENABLE 0x00000001
> +#define IXP4XX_WDT_IRQ_ENABLE 0x00000002
> +#define IXP4XX_WDT_COUNT_ENABLE 0x00000004
>
Please use
#define<space>DEFINE<tab>value
> -static void wdt_enable(void)
> +static inline
> +struct ixp4xx_wdt *to_ixp4xx_wdt(struct watchdog_device *wdd)
> {
> - spin_lock(&wdt_lock);
> - *IXP4XX_OSWK = IXP4XX_WDT_KEY;
> - *IXP4XX_OSWE = 0;
> - *IXP4XX_OSWT = WDT_TICK_RATE * heartbeat;
> - *IXP4XX_OSWE = IXP4XX_WDT_COUNT_ENABLE | IXP4XX_WDT_RESET_ENABLE;
> - *IXP4XX_OSWK = 0;
> - spin_unlock(&wdt_lock);
> + return container_of(wdd, struct ixp4xx_wdt, wdd);
> }
>
> -static void wdt_disable(void)
> +static int ixp4xx_wdt_start(struct watchdog_device *wdd)
> {
> - spin_lock(&wdt_lock);
> - *IXP4XX_OSWK = IXP4XX_WDT_KEY;
> - *IXP4XX_OSWE = 0;
> - *IXP4XX_OSWK = 0;
> - spin_unlock(&wdt_lock);
> -}
> + struct ixp4xx_wdt *iwdt = to_ixp4xx_wdt(wdd);
>
> -static int ixp4xx_wdt_open(struct inode *inode, struct file *file)
> -{
> - if (test_and_set_bit(WDT_IN_USE, &wdt_status))
> - return -EBUSY;
> + __raw_writel(IXP4XX_WDT_KEY, iwdt->base + IXP4XX_OSWK_OFFSET);
> + __raw_writel(0, iwdt->base + IXP4XX_OSWE_OFFSET);
> + __raw_writel(wdd->timeout * iwdt->rate,
> + iwdt->base + IXP4XX_OSWT_OFFSET);
> + __raw_writel(IXP4XX_WDT_COUNT_ENABLE | IXP4XX_WDT_RESET_ENABLE,
> + iwdt->base + IXP4XX_OSWE_OFFSET);
> + __raw_writel(0, iwdt->base + IXP4XX_OSWK_OFFSET);
>
> - clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
> - wdt_enable();
> - return stream_open(inode, file);
> -}
> -
> -static ssize_t
> -ixp4xx_wdt_write(struct file *file, const char *data, size_t len, loff_t *ppos)
> -{
> - if (len) {
> - if (!nowayout) {
> - size_t i;
> -
> - clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
> -
> - for (i = 0; i != len; i++) {
> - char c;
> -
> - if (get_user(c, data + i))
> - return -EFAULT;
> - if (c == 'V')
> - set_bit(WDT_OK_TO_CLOSE, &wdt_status);
> - }
> - }
> - wdt_enable();
> - }
> - return len;
> + return 0;
> }
>
> -static const struct watchdog_info ident = {
> - .options = WDIOF_CARDRESET | WDIOF_MAGICCLOSE |
> - WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
> - .identity = "IXP4xx Watchdog",
> -};
> -
> -
> -static long ixp4xx_wdt_ioctl(struct file *file, unsigned int cmd,
> - unsigned long arg)
> +static int ixp4xx_wdt_stop(struct watchdog_device *wdd)
> {
> - int ret = -ENOTTY;
> - int time;
> -
> - switch (cmd) {
> - case WDIOC_GETSUPPORT:
> - ret = copy_to_user((struct watchdog_info *)arg, &ident,
> - sizeof(ident)) ? -EFAULT : 0;
> - break;
> -
> - case WDIOC_GETSTATUS:
> - ret = put_user(0, (int *)arg);
> - break;
> -
> - case WDIOC_GETBOOTSTATUS:
> - ret = put_user(boot_status, (int *)arg);
> - break;
> -
> - case WDIOC_KEEPALIVE:
> - wdt_enable();
> - ret = 0;
> - break;
> -
> - case WDIOC_SETTIMEOUT:
> - ret = get_user(time, (int *)arg);
> - if (ret)
> - break;
> + struct ixp4xx_wdt *iwdt = to_ixp4xx_wdt(wdd);
>
> - if (time <= 0 || time > 60) {
> - ret = -EINVAL;
> - break;
> - }
> + __raw_writel(IXP4XX_WDT_KEY, iwdt->base + IXP4XX_OSWK_OFFSET);
> + __raw_writel(0, iwdt->base + IXP4XX_OSWE_OFFSET);
> + __raw_writel(0, iwdt->base + IXP4XX_OSWK_OFFSET);
>
> - heartbeat = time;
> - wdt_enable();
> - fallthrough;
> -
> - case WDIOC_GETTIMEOUT:
> - ret = put_user(heartbeat, (int *)arg);
> - break;
> - }
> - return ret;
> + return 0;
> }
>
> -static int ixp4xx_wdt_release(struct inode *inode, struct file *file)
> +static int ixp4xx_wdt_set_timeout(struct watchdog_device *wdd,
> + unsigned int timeout)
> {
> - if (test_bit(WDT_OK_TO_CLOSE, &wdt_status))
> - wdt_disable();
> - else
> - pr_crit("Device closed unexpectedly - timer will not stop\n");
> - clear_bit(WDT_IN_USE, &wdt_status);
> - clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
> + wdd->timeout = timeout;
> + if (watchdog_active(wdd))
> + ixp4xx_wdt_start(wdd);
>
> return 0;
> }
>
> -
> -static const struct file_operations ixp4xx_wdt_fops = {
> - .owner = THIS_MODULE,
> - .llseek = no_llseek,
> - .write = ixp4xx_wdt_write,
> - .unlocked_ioctl = ixp4xx_wdt_ioctl,
> - .compat_ioctl = compat_ptr_ioctl,
> - .open = ixp4xx_wdt_open,
> - .release = ixp4xx_wdt_release,
> +static const struct watchdog_ops ixp4xx_wdt_ops = {
> + .start = ixp4xx_wdt_start,
> + .stop = ixp4xx_wdt_stop,
> + .set_timeout = ixp4xx_wdt_set_timeout,
> + .owner = THIS_MODULE,
> };
>
> -static struct miscdevice ixp4xx_wdt_miscdev = {
> - .minor = WATCHDOG_MINOR,
> - .name = "watchdog",
> - .fops = &ixp4xx_wdt_fops,
> +static const struct watchdog_info ixp4xx_wdt_info = {
> + .options = WDIOF_KEEPALIVEPING
> + | WDIOF_MAGICCLOSE
> + | WDIOF_SETTIMEOUT,
> + .identity = KBUILD_MODNAME,
> };
>
> -static int __init ixp4xx_wdt_init(void)
> +/* Devres-handled clock disablement */
> +static void ixp4xx_clock_action(void *d)
> +{
> + struct clk *clk = d;
> +
> + clk_disable_unprepare(clk);
Oddly enough, while you can't call ixp4xx_clock_action() directly
with devm_add_action, you can call
clk_disable_unprepare(d);
directly, and the extra variable isn't needed.
> +}
> +
> +static int ixp4xx_wdt_probe(struct platform_device *pdev)
> {
> + struct device *dev = &pdev->dev;
> + struct ixp4xx_wdt *iwdt;
> + struct clk *clk;
> int ret;
>
> - /*
> - * FIXME: we bail out on device tree boot but this really needs
> - * to be fixed in a nicer way: this registers the MDIO bus before
> - * even matching the driver infrastructure, we should only probe
> - * detected hardware.
> - */
> - if (of_have_populated_dt())
> - return -ENODEV;
> if (!(read_cpuid_id() & 0xf) && !cpu_is_ixp46x()) {
> - pr_err("Rev. A0 IXP42x CPU detected - watchdog disabled\n");
> -
> + dev_err(dev, "Rev. A0 IXP42x CPU detected - watchdog disabled\n");
> return -ENODEV;
> }
> - boot_status = (*IXP4XX_OSST & IXP4XX_OSST_TIMER_WARM_RESET) ?
> - WDIOF_CARDRESET : 0;
> - ret = misc_register(&ixp4xx_wdt_miscdev);
> - if (ret == 0)
> - pr_info("timer heartbeat %d sec\n", heartbeat);
> - return ret;
> -}
>
> -static void __exit ixp4xx_wdt_exit(void)
> -{
> - misc_deregister(&ixp4xx_wdt_miscdev);
> -}
> + iwdt = devm_kzalloc(dev, sizeof(*iwdt), GFP_KERNEL);
> + if (!iwdt)
> + return -ENOMEM;
> + iwdt->base = dev->platform_data;
>
> + /*
> + * Retrieve rate from a fixed clock from the device tree if
> + * the parent has that, else use the default clock rate.
> + */
> + clk = devm_clk_get(dev->parent, NULL);
> + if (!IS_ERR(clk)) {
> + ret = clk_prepare_enable(clk);
> + if (ret)
> + return ret;
> + ret = devm_add_action_or_reset(dev, ixp4xx_clock_action, clk);
> + if (ret)
> + return ret;
> + iwdt->rate = clk_get_rate(clk);
> + }
> + if (!iwdt->rate)
> + iwdt->rate = IXP4XX_TIMER_FREQ;
>
> -module_init(ixp4xx_wdt_init);
> -module_exit(ixp4xx_wdt_exit);
> + iwdt->wdd.info = &ixp4xx_wdt_info;
> + iwdt->wdd.ops = &ixp4xx_wdt_ops;
> + iwdt->wdd.min_timeout = 1;
> + iwdt->wdd.max_timeout = U32_MAX / iwdt->rate;
> + iwdt->wdd.parent = dev;
> + /* Default to 60 seconds */
> + iwdt->wdd.timeout = 60U;
> + watchdog_init_timeout(&iwdt->wdd, 0, dev);
>
> -MODULE_AUTHOR("Deepak Saxena <dsaxena@xxxxxxxxxxx>");
> -MODULE_DESCRIPTION("IXP4xx Network Processor Watchdog");
> + if (__raw_readl(iwdt->base + IXP4XX_OSST_OFFSET) &
> + IXP4XX_OSST_TIMER_WARM_RESET)
> + iwdt->wdd.bootstatus = WDIOF_CARDRESET;
> +
> + ret = devm_watchdog_register_device(dev, &iwdt->wdd);
> + if (ret)
> + return ret;
> +
> + dev_info(dev, "IXP4xx watchdog available\n");
>
> -module_param(heartbeat, int, 0);
> -MODULE_PARM_DESC(heartbeat, "Watchdog heartbeat in seconds (default 60s)");
> + return 0;
> +}
>
> -module_param(nowayout, bool, 0);
> -MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started");
> +static struct platform_driver ixp4xx_wdt_driver = {
> + .probe = ixp4xx_wdt_probe,
> + .driver = {
> + .name = "ixp4xx-watchdog",
> + },
> +};
> +module_platform_driver(ixp4xx_wdt_driver);
>
> +MODULE_AUTHOR("Deepak Saxena <dsaxena@xxxxxxxxxxx>");
> +MODULE_DESCRIPTION("IXP4xx Network Processor Watchdog");
> MODULE_LICENSE("GPL");
> --
> 2.31.1
>
