[PATCH] watchdog: dw_wdt: convert to watchdog core api
Guenter Roeck
linux at roeck-us.net
Sun Jan 17 09:30:28 PST 2016
On 12/16/2015 02:27 AM, Jisheng Zhang wrote:
> Convert the dw_wdt driver to the new watchdog core api.
>
> Signed-off-by: Jisheng Zhang <jszhang at marvell.com>
> ---
> This patch depends on the signedness bug fix patch:
> http://lists.infradead.org/pipermail/linux-arm-kernel/2015-December/393872.html
>
Hi,
sorry for not getting back earlier.
I have a similar patch pending, but it depends on watchdog core changes which
are still being worked on. Hopefully those changes, together with the reworked
dw_wdt driver, can make it into 4.6.
Thanks,
Guenter
> drivers/watchdog/Kconfig | 1 +
> drivers/watchdog/dw_wdt.c | 316 +++++++++++++++++++---------------------------
> 2 files changed, 131 insertions(+), 186 deletions(-)
>
> diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
> index 7a8a6c6..886468a 100644
> --- a/drivers/watchdog/Kconfig
> +++ b/drivers/watchdog/Kconfig
> @@ -291,6 +291,7 @@ config SA1100_WATCHDOG
> config DW_WATCHDOG
> tristate "Synopsys DesignWare watchdog"
> depends on HAS_IOMEM
> + select WATCHDOG_CORE
> help
> Say Y here if to include support for the Synopsys DesignWare
> watchdog timer found in many chips.
> diff --git a/drivers/watchdog/dw_wdt.c b/drivers/watchdog/dw_wdt.c
> index 8fefa4ad..9e8706a 100644
> --- a/drivers/watchdog/dw_wdt.c
> +++ b/drivers/watchdog/dw_wdt.c
> @@ -24,10 +24,8 @@
> #include <linux/delay.h>
> #include <linux/device.h>
> #include <linux/err.h>
> -#include <linux/fs.h>
> #include <linux/io.h>
> #include <linux/kernel.h>
> -#include <linux/miscdevice.h>
> #include <linux/module.h>
> #include <linux/moduleparam.h>
> #include <linux/notifier.h>
> @@ -36,7 +34,6 @@
> #include <linux/platform_device.h>
> #include <linux/reboot.h>
> #include <linux/timer.h>
> -#include <linux/uaccess.h>
> #include <linux/watchdog.h>
>
> #define WDOG_CONTROL_REG_OFFSET 0x00
> @@ -59,59 +56,60 @@ MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started "
>
> #define WDT_TIMEOUT (HZ / 2)
>
> -static struct {
> +struct dw_wdt_device {
> void __iomem *regs;
> struct clk *clk;
> - unsigned long in_use;
> - unsigned long next_heartbeat;
> struct timer_list timer;
> - int expect_close;
> + struct watchdog_device wdog;
> struct notifier_block restart_handler;
> -} dw_wdt;
> +};
>
> -static inline int dw_wdt_is_enabled(void)
> +static inline bool dw_wdt_is_enabled(struct dw_wdt_device *wdev)
> {
> - return readl(dw_wdt.regs + WDOG_CONTROL_REG_OFFSET) &
> + return readl(wdev->regs + WDOG_CONTROL_REG_OFFSET) &
> WDOG_CONTROL_REG_WDT_EN_MASK;
> }
>
> -static inline int dw_wdt_top_in_seconds(unsigned top)
> +static inline unsigned int dw_wdt_top_in_seconds(struct dw_wdt_device *wdev,
> + unsigned int top)
> {
> /*
> * There are 16 possible timeout values in 0..15 where the number of
> * cycles is 2 ^ (16 + i) and the watchdog counts down.
> */
> - return (1U << (16 + top)) / clk_get_rate(dw_wdt.clk);
> + return (1U << (16 + top)) / clk_get_rate(wdev->clk);
> }
>
> -static int dw_wdt_get_top(void)
> +static unsigned int dw_wdt_get_timeleft(struct watchdog_device *wdog)
> {
> - int top = readl(dw_wdt.regs + WDOG_TIMEOUT_RANGE_REG_OFFSET) & 0xF;
> + struct dw_wdt_device *wdev = watchdog_get_drvdata(wdog);
>
> - return dw_wdt_top_in_seconds(top);
> + return readl(wdev->regs + WDOG_CURRENT_COUNT_REG_OFFSET) /
> + clk_get_rate(wdev->clk);
> }
>
> -static inline void dw_wdt_set_next_heartbeat(void)
> +static int dw_wdt_ping(struct watchdog_device *wdog)
> {
> - dw_wdt.next_heartbeat = jiffies + dw_wdt_get_top() * HZ;
> -}
> + struct dw_wdt_device *wdev = watchdog_get_drvdata(wdog);
>
> -static void dw_wdt_keepalive(void)
> -{
> - writel(WDOG_COUNTER_RESTART_KICK_VALUE, dw_wdt.regs +
> + writel(WDOG_COUNTER_RESTART_KICK_VALUE, wdev->regs +
> WDOG_COUNTER_RESTART_REG_OFFSET);
> +
> + return 0;
> }
>
> -static int dw_wdt_set_top(unsigned top_s)
> +static int dw_wdt_set_timeout(struct watchdog_device *wdog,
> + unsigned int new_timeout)
> {
> - int i, top_val = DW_WDT_MAX_TOP;
> + unsigned int i, top_val = DW_WDT_MAX_TOP;
> + struct dw_wdt_device *wdev = watchdog_get_drvdata(wdog);
>
> /*
> * Iterate over the timeout values until we find the closest match. We
> * always look for >=.
> */
> for (i = 0; i <= DW_WDT_MAX_TOP; ++i)
> - if (dw_wdt_top_in_seconds(i) >= top_s) {
> + if (dw_wdt_top_in_seconds(wdev, i) >= new_timeout) {
> top_val = i;
> break;
> }
> @@ -123,33 +121,34 @@ static int dw_wdt_set_top(unsigned top_s)
> * effectively get a pat of the watchdog right here.
> */
> writel(top_val | top_val << WDOG_TIMEOUT_RANGE_TOPINIT_SHIFT,
> - dw_wdt.regs + WDOG_TIMEOUT_RANGE_REG_OFFSET);
> + wdev->regs + WDOG_TIMEOUT_RANGE_REG_OFFSET);
>
> /*
> * Add an explicit pat to handle versions of the watchdog that
> * don't have TOPINIT. This won't hurt on versions that have
> * it.
> */
> - dw_wdt_keepalive();
> -
> - dw_wdt_set_next_heartbeat();
> + dw_wdt_ping(wdog);
>
> - return dw_wdt_top_in_seconds(top_val);
> + return 0;
> }
>
> static int dw_wdt_restart_handle(struct notifier_block *this,
> unsigned long mode, void *cmd)
> {
> u32 val;
> + struct dw_wdt_device *wdev = container_of(this,
> + struct dw_wdt_device,
> + restart_handler);
>
> - writel(0, dw_wdt.regs + WDOG_TIMEOUT_RANGE_REG_OFFSET);
> - val = readl(dw_wdt.regs + WDOG_CONTROL_REG_OFFSET);
> + writel(0, wdev->regs + WDOG_TIMEOUT_RANGE_REG_OFFSET);
> + val = readl(wdev->regs + WDOG_CONTROL_REG_OFFSET);
> if (val & WDOG_CONTROL_REG_WDT_EN_MASK)
> - writel(WDOG_COUNTER_RESTART_KICK_VALUE, dw_wdt.regs +
> + writel(WDOG_COUNTER_RESTART_KICK_VALUE, wdev->regs +
> WDOG_COUNTER_RESTART_REG_OFFSET);
> else
> writel(WDOG_CONTROL_REG_WDT_EN_MASK,
> - dw_wdt.regs + WDOG_CONTROL_REG_OFFSET);
> + wdev->regs + WDOG_CONTROL_REG_OFFSET);
>
> /* wait for reset to assert... */
> mdelay(500);
> @@ -157,74 +156,52 @@ static int dw_wdt_restart_handle(struct notifier_block *this,
> return NOTIFY_DONE;
> }
>
> -static void dw_wdt_ping(unsigned long data)
> +static void dw_wdt_timer_ping(unsigned long arg)
> {
> - if (time_before(jiffies, dw_wdt.next_heartbeat) ||
> - (!nowayout && !dw_wdt.in_use)) {
> - dw_wdt_keepalive();
> - mod_timer(&dw_wdt.timer, jiffies + WDT_TIMEOUT);
> - } else
> - pr_crit("keepalive missed, machine will reset\n");
> + struct watchdog_device *wdog = (struct watchdog_device *)arg;
> + struct dw_wdt_device *wdev = watchdog_get_drvdata(wdog);
> +
> + /* ping it every wdog->timeout / 2 seconds to prevent reboot */
> + dw_wdt_ping(wdog);
> + mod_timer(&wdev->timer, jiffies + wdog->timeout * HZ / 2);
> }
>
> -static int dw_wdt_open(struct inode *inode, struct file *filp)
> +static int dw_wdt_start(struct watchdog_device *wdog)
> {
> - if (test_and_set_bit(0, &dw_wdt.in_use))
> - return -EBUSY;
> -
> - /* Make sure we don't get unloaded. */
> - __module_get(THIS_MODULE);
> -
> - if (!dw_wdt_is_enabled()) {
> - /*
> - * The watchdog is not currently enabled. Set the timeout to
> - * something reasonable and then start it.
> - */
> - dw_wdt_set_top(DW_WDT_DEFAULT_SECONDS);
> + struct dw_wdt_device *wdev = watchdog_get_drvdata(wdog);
> +
> + if (!dw_wdt_is_enabled(wdev)) {
> + dw_wdt_set_timeout(wdog, wdog->timeout);
> writel(WDOG_CONTROL_REG_WDT_EN_MASK,
> - dw_wdt.regs + WDOG_CONTROL_REG_OFFSET);
> + wdev->regs + WDOG_CONTROL_REG_OFFSET);
> + } else {
> + /* delete the timer that pings the watchdog after close */
> + del_timer_sync(&wdev->timer);
> + dw_wdt_set_timeout(wdog, wdog->timeout);
> }
>
> - dw_wdt_set_next_heartbeat();
> -
> - return nonseekable_open(inode, filp);
> + return 0;
> }
>
> -static ssize_t dw_wdt_write(struct file *filp, const char __user *buf,
> - size_t len, loff_t *offset)
> +static int dw_wdt_stop(struct watchdog_device *wdog)
> {
> - if (!len)
> - return 0;
> -
> - if (!nowayout) {
> - size_t i;
> -
> - dw_wdt.expect_close = 0;
> -
> - for (i = 0; i < len; ++i) {
> - char c;
> -
> - if (get_user(c, buf + i))
> - return -EFAULT;
> -
> - if (c == 'V') {
> - dw_wdt.expect_close = 1;
> - break;
> - }
> - }
> - }
> -
> - dw_wdt_set_next_heartbeat();
> - dw_wdt_keepalive();
> - mod_timer(&dw_wdt.timer, jiffies + WDT_TIMEOUT);
> -
> - return len;
> + /*
> + * We don't need a clk_disable_unprepare, the wdt cannot be disabled
> + * once started. We use a timer to ping the watchdog while the
> + * /dev/watchdog is closed
> + */
> + dw_wdt_timer_ping((unsigned long)wdog);
> + return 0;
> }
>
> -static u32 dw_wdt_time_left(void)
> +static inline void dw_wdt_ping_if_active(struct watchdog_device *wdog)
> {
> - return readl(dw_wdt.regs + WDOG_CURRENT_COUNT_REG_OFFSET) /
> - clk_get_rate(dw_wdt.clk);
> + struct dw_wdt_device *wdev = watchdog_get_drvdata(wdog);
> +
> + if (dw_wdt_is_enabled(wdev)) {
> + dw_wdt_set_timeout(wdog, wdog->timeout);
> + dw_wdt_timer_ping((unsigned long)wdog);
> + }
> }
>
> static const struct watchdog_info dw_wdt_ident = {
> @@ -233,78 +210,37 @@ static const struct watchdog_info dw_wdt_ident = {
> .identity = "Synopsys DesignWare Watchdog",
> };
>
> -static long dw_wdt_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
> -{
> - unsigned long val;
> - int timeout;
> -
> - switch (cmd) {
> - case WDIOC_GETSUPPORT:
> - return copy_to_user((void __user *)arg, &dw_wdt_ident,
> - sizeof(dw_wdt_ident)) ? -EFAULT : 0;
> -
> - case WDIOC_GETSTATUS:
> - case WDIOC_GETBOOTSTATUS:
> - return put_user(0, (int __user *)arg);
> -
> - case WDIOC_KEEPALIVE:
> - dw_wdt_set_next_heartbeat();
> - return 0;
> -
> - case WDIOC_SETTIMEOUT:
> - if (get_user(val, (int __user *)arg))
> - return -EFAULT;
> - timeout = dw_wdt_set_top(val);
> - return put_user(timeout , (int __user *)arg);
> -
> - case WDIOC_GETTIMEOUT:
> - return put_user(dw_wdt_get_top(), (int __user *)arg);
> -
> - case WDIOC_GETTIMELEFT:
> - /* Get the time left until expiry. */
> - if (get_user(val, (int __user *)arg))
> - return -EFAULT;
> - return put_user(dw_wdt_time_left(), (int __user *)arg);
> -
> - default:
> - return -ENOTTY;
> - }
> -}
> -
> -static int dw_wdt_release(struct inode *inode, struct file *filp)
> -{
> - clear_bit(0, &dw_wdt.in_use);
> -
> - if (!dw_wdt.expect_close) {
> - del_timer(&dw_wdt.timer);
> -
> - if (!nowayout)
> - pr_crit("unexpected close, system will reboot soon\n");
> - else
> - pr_crit("watchdog cannot be disabled, system will reboot soon\n");
> - }
> -
> - dw_wdt.expect_close = 0;
> -
> - return 0;
> -}
> +static const struct watchdog_ops dw_wdt_ops = {
> + .owner = THIS_MODULE,
> + .start = dw_wdt_start,
> + .stop = dw_wdt_stop,
> + .ping = dw_wdt_ping,
> + .set_timeout = dw_wdt_set_timeout,
> + .get_timeleft = dw_wdt_get_timeleft,
> +};
>
> #ifdef CONFIG_PM_SLEEP
> static int dw_wdt_suspend(struct device *dev)
> {
> - clk_disable_unprepare(dw_wdt.clk);
> + struct watchdog_device *wdog = dev_get_drvdata(dev);
> + struct dw_wdt_device *wdev = watchdog_get_drvdata(wdog);
> +
> + clk_disable_unprepare(wdev->clk);
>
> return 0;
> }
>
> static int dw_wdt_resume(struct device *dev)
> {
> - int err = clk_prepare_enable(dw_wdt.clk);
> + struct watchdog_device *wdog = dev_get_drvdata(dev);
> + struct dw_wdt_device *wdev = watchdog_get_drvdata(wdog);
> +
> + int err = clk_prepare_enable(wdev->clk);
>
> if (err)
> return err;
>
> - dw_wdt_keepalive();
> + dw_wdt_ping(wdog);
>
> return 0;
> }
> @@ -312,67 +248,75 @@ static int dw_wdt_resume(struct device *dev)
>
> static SIMPLE_DEV_PM_OPS(dw_wdt_pm_ops, dw_wdt_suspend, dw_wdt_resume);
>
> -static const struct file_operations wdt_fops = {
> - .owner = THIS_MODULE,
> - .llseek = no_llseek,
> - .open = dw_wdt_open,
> - .write = dw_wdt_write,
> - .unlocked_ioctl = dw_wdt_ioctl,
> - .release = dw_wdt_release
> -};
> -
> -static struct miscdevice dw_wdt_miscdev = {
> - .fops = &wdt_fops,
> - .name = "watchdog",
> - .minor = WATCHDOG_MINOR,
> -};
> -
> static int dw_wdt_drv_probe(struct platform_device *pdev)
> {
> int ret;
> - struct resource *mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> -
> - dw_wdt.regs = devm_ioremap_resource(&pdev->dev, mem);
> - if (IS_ERR(dw_wdt.regs))
> - return PTR_ERR(dw_wdt.regs);
> -
> - dw_wdt.clk = devm_clk_get(&pdev->dev, NULL);
> - if (IS_ERR(dw_wdt.clk))
> - return PTR_ERR(dw_wdt.clk);
> -
> - ret = clk_prepare_enable(dw_wdt.clk);
> + struct dw_wdt_device *wdev;
> + struct watchdog_device *wdog;
> + struct resource *mem;
> +
> + wdev = devm_kzalloc(&pdev->dev, sizeof(*wdev), GFP_KERNEL);
> + if (!wdev)
> + return -ENOMEM;
> +
> + mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> + wdev->regs = devm_ioremap_resource(&pdev->dev, mem);
> + if (IS_ERR(wdev->regs))
> + return PTR_ERR(wdev->regs);
> +
> + wdev->clk = devm_clk_get(&pdev->dev, NULL);
> + if (IS_ERR(wdev->clk))
> + return PTR_ERR(wdev->clk);
> +
> + wdog = &wdev->wdog;
> + wdog->info = &dw_wdt_ident;
> + wdog->ops = &dw_wdt_ops;
> + wdog->min_timeout = dw_wdt_top_in_seconds(wdev, 0);
> + wdog->max_timeout = dw_wdt_top_in_seconds(wdev, DW_WDT_MAX_TOP);
> +
> + ret = clk_prepare_enable(wdev->clk);
> if (ret)
> return ret;
>
> - ret = misc_register(&dw_wdt_miscdev);
> - if (ret)
> - goto out_disable_clk;
> + platform_set_drvdata(pdev, wdog);
> + watchdog_set_drvdata(wdog, wdev);
> + watchdog_set_nowayout(wdog, nowayout);
> + watchdog_init_timeout(wdog, wdog->max_timeout, &pdev->dev);
>
> - dw_wdt.restart_handler.notifier_call = dw_wdt_restart_handle;
> - dw_wdt.restart_handler.priority = 128;
> - ret = register_restart_handler(&dw_wdt.restart_handler);
> + wdev->restart_handler.notifier_call = dw_wdt_restart_handle;
> + wdev->restart_handler.priority = 128;
> + ret = register_restart_handler(&wdev->restart_handler);
> if (ret)
> - pr_warn("cannot register restart handler\n");
> + dev_warn(&pdev->dev, "cannot register restart handler\n");
>
> - dw_wdt_set_next_heartbeat();
> - setup_timer(&dw_wdt.timer, dw_wdt_ping, 0);
> - mod_timer(&dw_wdt.timer, jiffies + WDT_TIMEOUT);
> + setup_timer(&wdev->timer, dw_wdt_timer_ping, (unsigned long)wdog);
> +
> + dw_wdt_ping_if_active(wdog);
> +
> + ret = watchdog_register_device(wdog);
> + if (ret) {
> + dev_err(&pdev->dev, "cannot register watchdog device\n");
> + goto out_disable_clk;
> + }
>
> return 0;
>
> out_disable_clk:
> - clk_disable_unprepare(dw_wdt.clk);
> + clk_disable_unprepare(wdev->clk);
>
> return ret;
> }
>
> static int dw_wdt_drv_remove(struct platform_device *pdev)
> {
> - unregister_restart_handler(&dw_wdt.restart_handler);
> + struct watchdog_device *wdog = platform_get_drvdata(pdev);
> + struct dw_wdt_device *wdev = watchdog_get_drvdata(wdog);
> +
> + unregister_restart_handler(&wdev->restart_handler);
>
> - misc_deregister(&dw_wdt_miscdev);
> + watchdog_unregister_device(wdog);
>
> - clk_disable_unprepare(dw_wdt.clk);
> + clk_disable_unprepare(wdev->clk);
>
> return 0;
> }
>
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