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Date: Tue, 2 Aug 2011 11:55:36 -0500
From: H Hartley Sweeten <hartleys@...ionengravers.com>
To: Mika Westerberg <mika.westerberg@...ux.intel.com>
CC: Linux Kernel <linux-kernel@...r.kernel.org>,
"linux-watchdog@...r.kernel.org" <linux-watchdog@...r.kernel.org>,
"wim@...ana.be" <wim@...ana.be>
Subject: RE: [RFC PATCH] watchdog: ep93xx: Use the WatchDog Timer Driver
Core.
On Tuesday, August 02, 2011 2:17 AM, Mika Westerberg wrote:
> On Mon, Aug 01, 2011 at 01:57:24PM -0700, H Hartley Sweeten wrote:
>> Signed-off-by: H Hartley Sweeten <hsweeten@...ionengravers.com>
>> Cc: Wim Van Sebroeck <wim@...ana.be> (maintainer:WATCHDOG DEVICE D...)
>
> Nice. I'll try to test the patch later today.
>
> I have few minor comments, see below.
>
>>
>> ---
>>
>> diff --git a/drivers/watchdog/ep93xx_wdt.c b/drivers/watchdog/ep93xx_wdt.c
>> index 726b7df..bb97351 100644
>> --- a/drivers/watchdog/ep93xx_wdt.c
>> +++ b/drivers/watchdog/ep93xx_wdt.c
>> @@ -24,11 +24,9 @@
>> */
>>
>> #include <linux/module.h>
>> -#include <linux/fs.h>
>> #include <linux/miscdevice.h>
>
> Is the above header still needed?
I think so due to the MODULE_ALIAS_MISCDEV() at the end of the file. But,
I'm not sure if that is really needed... Wim?
>> #include <linux/watchdog.h>
>> #include <linux/timer.h>
>> -#include <linux/uaccess.h>
>> #include <linux/io.h>
>> #include <mach/hardware.h>
>>
>> @@ -39,15 +37,17 @@
>> #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)
>> @@ -71,130 +71,46 @@ static inline void wdt_ping(void)
>> __raw_writew(0x5555, EP93XX_WDT_WATCHDOG);
>> }
>>
>> -static void wdt_startup(void)
>> +static int void ep93xx_wdt_start(struct watchdog_device *wdd)
> ^^^^
> extra 'void' above
Argh... I need more sleep... I guess that's what happens when your first
child is born...
Fixed.
>> {
>> - next_heartbeat = jiffies + (timeout * HZ);
>> + next_heartbeat = jiffies + (wdd->timeout * HZ);
>>
>> wdt_enable();
>> 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();
>> + 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,
>> + .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)
>> @@ -210,43 +126,31 @@ static int __init ep93xx_wdt_init(void)
>> {
>> int err;
>>
>> - err = misc_register(&ep93xx_wdt_miscdev);
>> + ep93xx_wdd.bootstatus = readl(EP93XX_WDT_WATCHDOG);
>> + ep93xx_wdd.timeout = timeout;
>
> Should you check that the given timeout is in valid range here, like it is
> done in the original driver?
I thought the core would handle that. If not maybe it should validate the
timeout based on the min/max values. Wim?
>> +
>> + err = watchdog_register_device(&ep93xx_wdd);
>> + if (err)
>> + return err;
>>
>> - boot_status = __raw_readl(EP93XX_WDT_WATCHDOG) & 0x01 ? 1 : 0;
>> + setup_timer(&timer, ep93xx_timer_ping, 1);
>>
>> printk(KERN_INFO PFX "EP93XX watchdog, driver version "
>> WDT_VERSION "%s\n",
>> - (__raw_readl(EP93XX_WDT_WATCHDOG) & 0x08)
>> + (ep93xx_wdd.bootstatus & 0x08)
>> ? " (nCS1 disable detected)" : "");
>>
>> - if (timeout < 1 || timeout > 3600) {
>> - timeout = WDT_TIMEOUT;
>> - printk(KERN_INFO PFX
>> - "timeout value must be 1<=x<=3600, using %d\n",
>> - timeout);
>> - }
>> -
>> - setup_timer(&timer, ep93xx_timer_ping, 1);
>> - return err;
>> + return 0;
>> }
>> +module_init(ep93xx_wdt_init);
>>
>> static void __exit ep93xx_wdt_exit(void)
>> {
>> - wdt_shutdown();
>> - misc_deregister(&ep93xx_wdt_miscdev);
>> + wdt_shutdown(&ep93xx_wdd);
>
> ep93xx_wdt_stop(&ep93xx_wdd);
Oops.. You are correct. Fixed.
>> + 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");
Thanks for the feedback. I'll post an updated patch later.
Regards,
Hartley--
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