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Message-ID: <20110804181244.GA2445@mwesterb-mobl.ger.corp.intel.com>
Date: Thu, 4 Aug 2011 21:12:44 +0300
From: Mika Westerberg <mika.westerberg@....fi>
To: H Hartley Sweeten <hartleys@...ionengravers.com>
Cc: Linux Kernel <linux-kernel@...r.kernel.org>,
linux-watchdog@...r.kernel.org, wim@...ana.be,
mika.westerberg@...ux.intel.com
Subject: Re: [RFC PATCH v2] watchdog: ep93xx: Use the WatchDog Timer Driver
Core.
On Wed, Aug 03, 2011 at 10:21:26AM -0700, H Hartley Sweeten wrote:
> Convert the ep93xx watchdog driver to using the WatchDog Timer Driver Core.
>
> Signed-off-by: H Hartley Sweeten <hsweeten@...ionengravers.com>
> Cc: Wim Van Sebroeck <wim@...ana.be>
> Cc: Mika Westerberg <mika.westerberg@...ux.intel.com>
Tested-by: Mika Westerberg <mika.westerberg@....fi>
BTW, now that the driver uses watchdog core should we also select
WATCHDOG_CORE in the Kconfig? If it is not enabled we get:
drivers/built-in.o: In function `ep93xx_wdt_init':
clkdev.c:(.init.text+0x2bd8): undefined reference to
`watchdog_register_device'
make: *** [.tmp_vmlinux1] Error 1
Other than that, you can also add my
Reviewed-by: Mika Westerberg <mika.westerberg@....fi>
if you like.
>
> ---
>
> v2: use the pr_* functions instead of printk(KERN_* PFX
> document the register magic numbers and bits
> fold the register access functions into the callers
> add WDIOF_KEEPALIVEPING to the options
> fix the bootstatus use, any detected reset is reported as WDIOF_CARDRESET
> add a boot message so the user can see what actually caused the reset
> validate that the user's requested timeout is actually valid
> fix a typo in the v1 patch (extra void in ep93xx_wdt_start)
> fix ep93xx_wdt_exit, ep93xx_wdt_stop should be called not wdt_shutdown
>
> diff --git a/drivers/watchdog/ep93xx_wdt.c b/drivers/watchdog/ep93xx_wdt.c
> index 726b7df..4309db3 100644
> --- a/drivers/watchdog/ep93xx_wdt.c
> +++ b/drivers/watchdog/ep93xx_wdt.c
> @@ -23,184 +23,102 @@
> * - Add a few missing ioctls
> */
>
> +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
> +
> #include <linux/module.h>
> -#include <linux/fs.h>
> #include <linux/miscdevice.h>
> #include <linux/watchdog.h>
> #include <linux/timer.h>
> -#include <linux/uaccess.h>
> #include <linux/io.h>
> #include <mach/hardware.h>
>
> #define WDT_VERSION "0.3"
> -#define PFX "ep93xx_wdt: "
>
> /* default timeout (secs) */
> #define WDT_TIMEOUT 30
>
> static int nowayout = WATCHDOG_NOWAYOUT;
> +module_param(nowayout, int, 0);
> +MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started");
> +
> static int timeout = WDT_TIMEOUT;
> +module_param(timeout, int, 0);
> +MODULE_PARM_DESC(timeout,
> + "Watchdog timeout in seconds. (1<=timeout<=3600, default="
> + __MODULE_STRING(WDT_TIMEOUT) ")");
>
> static struct timer_list timer;
> static unsigned long next_heartbeat;
> -static unsigned long wdt_status;
> -static unsigned long boot_status;
> -
> -#define WDT_IN_USE 0
> -#define WDT_OK_TO_CLOSE 1
>
> #define EP93XX_WDT_REG(x) (EP93XX_WATCHDOG_BASE + (x))
> #define EP93XX_WDT_WATCHDOG EP93XX_WDT_REG(0x00)
> #define EP93XX_WDT_WDSTATUS EP93XX_WDT_REG(0x04)
>
> +/* Watchdog register write only values */
> +#define EP93XX_WATCHDOG_RESTART 0x5555
> +#define EP93XX_WATCHDOG_DISABLE 0xaa55
> +#define EP93XX_WATCHDOG_ENABLE 0xaaaa
> +
> +/* Watchdog register read only bits */
> +#define EP93XX_WATCHDOG_PLSDSN (1 << 6)
> +#define EP93XX_WATCHDOG_OVRID (1 << 5)
> +#define EP93XX_WATCHDOG_SWDIS (1 << 4)
> +#define EP93XX_WATCHDOG_HWDIS (1 << 3)
> +#define EP93XX_WATCHDOG_URST (1 << 2)
> +#define EP93XX_WATCHDOG_3KRST (1 << 1)
> +#define EP93XX_WATCHDOG_WD (1 << 0)
> +#define EP93XX_WATCHDOG_RESET_MASK (0x07)
> +
> /* reset the wdt every ~200ms */
> #define WDT_INTERVAL (HZ/5)
>
> -static void wdt_enable(void)
> -{
> - __raw_writew(0xaaaa, EP93XX_WDT_WATCHDOG);
> -}
> -
> -static void wdt_disable(void)
> +static int ep93xx_wdt_start(struct watchdog_device *wdd)
> {
> - __raw_writew(0xaa55, EP93XX_WDT_WATCHDOG);
> -}
> -
> -static inline void wdt_ping(void)
> -{
> - __raw_writew(0x5555, EP93XX_WDT_WATCHDOG);
> -}
> + next_heartbeat = jiffies + (wdd->timeout * HZ);
>
> -static void wdt_startup(void)
> -{
> - next_heartbeat = jiffies + (timeout * HZ);
> -
> - wdt_enable();
> + __raw_writew(EP93XX_WATCHDOG_ENABLE, EP93XX_WDT_WATCHDOG);
> mod_timer(&timer, jiffies + WDT_INTERVAL);
> + return 0;
> }
>
> -static void wdt_shutdown(void)
> +static int ep93xx_wdt_stop(struct watchdog_device *wdd)
> {
> del_timer_sync(&timer);
> - wdt_disable();
> + __raw_writew(EP93XX_WATCHDOG_DISABLE, EP93XX_WDT_WATCHDOG);
> + return 0;
> }
>
> -static void wdt_keepalive(void)
> +static int ep93xx_wdt_keepalive(struct watchdog_device *wdd)
> {
> /* user land ping */
> - next_heartbeat = jiffies + (timeout * HZ);
> -}
> -
> -static int ep93xx_wdt_open(struct inode *inode, struct file *file)
> -{
> - if (test_and_set_bit(WDT_IN_USE, &wdt_status))
> - return -EBUSY;
> -
> - clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
> -
> - wdt_startup();
> -
> - return nonseekable_open(inode, file);
> -}
> -
> -static ssize_t
> -ep93xx_wdt_write(struct file *file, const char __user *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);
> - else
> - clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
> - }
> - }
> - wdt_keepalive();
> - }
> -
> - return len;
> + next_heartbeat = jiffies + (wdd->timeout * HZ);
> + return 0;
> }
>
> -static const struct watchdog_info ident = {
> - .options = WDIOF_CARDRESET | WDIOF_MAGICCLOSE,
> - .identity = "EP93xx Watchdog",
> +static const struct watchdog_info ep93xx_wdt_ident = {
> + .options = WDIOF_CARDRESET | WDIOF_MAGICCLOSE |
> + WDIOF_KEEPALIVEPING,
> + .identity = "EP93xx Watchdog",
> };
>
> -static long ep93xx_wdt_ioctl(struct file *file,
> - unsigned int cmd, unsigned long arg)
> -{
> - int ret = -ENOTTY;
> -
> - switch (cmd) {
> - case WDIOC_GETSUPPORT:
> - ret = copy_to_user((struct watchdog_info __user *)arg, &ident,
> - sizeof(ident)) ? -EFAULT : 0;
> - break;
> -
> - case WDIOC_GETSTATUS:
> - ret = put_user(0, (int __user *)arg);
> - break;
> -
> - case WDIOC_GETBOOTSTATUS:
> - ret = put_user(boot_status, (int __user *)arg);
> - break;
> -
> - case WDIOC_KEEPALIVE:
> - wdt_keepalive();
> - ret = 0;
> - break;
> -
> - case WDIOC_GETTIMEOUT:
> - /* actually, it is 0.250 seconds.... */
> - ret = put_user(1, (int __user *)arg);
> - break;
> - }
> - return ret;
> -}
> -
> -static int ep93xx_wdt_release(struct inode *inode, struct file *file)
> -{
> - if (test_bit(WDT_OK_TO_CLOSE, &wdt_status))
> - wdt_shutdown();
> - else
> - printk(KERN_CRIT PFX
> - "Device closed unexpectedly - timer will not stop\n");
> -
> - clear_bit(WDT_IN_USE, &wdt_status);
> - clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
> -
> - return 0;
> -}
> -
> -static const struct file_operations ep93xx_wdt_fops = {
> +static const struct watchdog_ops ep93xx_wdt_ops = {
> .owner = THIS_MODULE,
> - .write = ep93xx_wdt_write,
> - .unlocked_ioctl = ep93xx_wdt_ioctl,
> - .open = ep93xx_wdt_open,
> - .release = ep93xx_wdt_release,
> - .llseek = no_llseek,
> + .start = ep93xx_wdt_start,
> + .stop = ep93xx_wdt_stop,
> + .ping = ep93xx_wdt_keepalive,
> };
>
> -static struct miscdevice ep93xx_wdt_miscdev = {
> - .minor = WATCHDOG_MINOR,
> - .name = "watchdog",
> - .fops = &ep93xx_wdt_fops,
> +static struct watchdog_device ep93xx_wdd = {
> + .info = &ep93xx_wdt_ident,
> + .ops = &ep93xx_wdt_ops,
> + .min_timeout = 1,
> + .max_timeout = 3600,
> };
>
> static void ep93xx_timer_ping(unsigned long data)
> {
> if (time_before(jiffies, next_heartbeat))
> - wdt_ping();
> + __raw_writew(EP93XX_WATCHDOG_RESTART, EP93XX_WDT_WATCHDOG);
>
> /* Re-set the timer interval */
> mod_timer(&timer, jiffies + WDT_INTERVAL);
> @@ -208,45 +126,50 @@ static void ep93xx_timer_ping(unsigned long data)
>
> static int __init ep93xx_wdt_init(void)
> {
> + int v;
> int err;
>
> - err = misc_register(&ep93xx_wdt_miscdev);
> -
> - boot_status = __raw_readl(EP93XX_WDT_WATCHDOG) & 0x01 ? 1 : 0;
> -
> - printk(KERN_INFO PFX "EP93XX watchdog, driver version "
> - WDT_VERSION "%s\n",
> - (__raw_readl(EP93XX_WDT_WATCHDOG) & 0x08)
> - ? " (nCS1 disable detected)" : "");
> + v = readl(EP93XX_WDT_WATCHDOG);
> + ep93xx_wdd.bootstatus = (v & EP93XX_WATCHDOG_RESET_MASK)
> + ? WDIOF_CARDRESET : 0;
> + if (ep93xx_wdd.bootstatus) {
> + /* Only a power-on-reset will clear these bits */
> + pr_info("Last reset was due to %s%s%s\n",
> + (v & EP93XX_WATCHDOG_WD) ? "- watchdog timeout " : "",
> + (v & EP93XX_WATCHDOG_3KRST) ? "- 3-key reset " : "",
> + (v & EP93XX_WATCHDOG_URST) ? "- user reset" : "");
> + }
>
> - if (timeout < 1 || timeout > 3600) {
> - timeout = WDT_TIMEOUT;
> - printk(KERN_INFO PFX
> - "timeout value must be 1<=x<=3600, using %d\n",
> - timeout);
> + if (timeout < ep93xx_wdd.min_timeout ||
> + timeout > ep93xx_wdd.max_timeout) {
> + ep93xx_wdd.timeout = WDT_TIMEOUT;
> + pr_info("timeout value must be %d<=x<=%d, using %d\n",
> + ep93xx_wdd.min_timeout, ep93xx_wdd.max_timeout,
> + ep93xx_wdd.timeout);
> + } else {
> + ep93xx_wdd.timeout = timeout;
> }
>
> + err = watchdog_register_device(&ep93xx_wdd);
> + if (err)
> + return err;
> +
> setup_timer(&timer, ep93xx_timer_ping, 1);
> - return err;
> +
> + pr_info("EP93XX watchdog, driver version " WDT_VERSION "%s\n",
> + (v & EP93XX_WATCHDOG_HWDIS) ? " (nCS1 disable detected)" : "");
> +
> + return 0;
> }
> +module_init(ep93xx_wdt_init);
>
> static void __exit ep93xx_wdt_exit(void)
> {
> - wdt_shutdown();
> - misc_deregister(&ep93xx_wdt_miscdev);
> + ep93xx_wdt_stop(&ep93xx_wdd);
> + watchdog_unregister_device(&ep93xx_wdd);
> }
> -
> -module_init(ep93xx_wdt_init);
> module_exit(ep93xx_wdt_exit);
>
> -module_param(nowayout, int, 0);
> -MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started");
> -
> -module_param(timeout, int, 0);
> -MODULE_PARM_DESC(timeout,
> - "Watchdog timeout in seconds. (1<=timeout<=3600, default="
> - __MODULE_STRING(WDT_TIMEOUT) ")");
> -
> MODULE_AUTHOR("Ray Lehtiniemi <rayl@...l.com>,"
> "Alessandro Zummo <a.zummo@...ertech.it>");
> MODULE_DESCRIPTION("EP93xx Watchdog");
--
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