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294 lines
6.2 KiB
294 lines
6.2 KiB
/*
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* drivers/watchdog/orion5x_wdt.c
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*
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* Watchdog driver for Orion5x processors
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*
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* Author: Sylver Bruneau <sylver.bruneau@googlemail.com>
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*
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* This file is licensed under the terms of the GNU General Public
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* License version 2. This program is licensed "as is" without any
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* warranty of any kind, whether express or implied.
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*/
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#include <linux/module.h>
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#include <linux/moduleparam.h>
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#include <linux/types.h>
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#include <linux/kernel.h>
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#include <linux/fs.h>
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#include <linux/miscdevice.h>
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#include <linux/platform_device.h>
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#include <linux/watchdog.h>
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#include <linux/init.h>
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#include <linux/uaccess.h>
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#include <linux/io.h>
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#include <linux/spinlock.h>
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#include <plat/orion5x_wdt.h>
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/*
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* Watchdog timer block registers.
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*/
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#define TIMER_CTRL (TIMER_VIRT_BASE + 0x0000)
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#define WDT_EN 0x0010
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#define WDT_VAL (TIMER_VIRT_BASE + 0x0024)
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#define WDT_MAX_CYCLE_COUNT 0xffffffff
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#define WDT_IN_USE 0
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#define WDT_OK_TO_CLOSE 1
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static int nowayout = WATCHDOG_NOWAYOUT;
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static int heartbeat = -1; /* module parameter (seconds) */
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static unsigned int wdt_max_duration; /* (seconds) */
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static unsigned int wdt_tclk;
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static unsigned long wdt_status;
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static spinlock_t wdt_lock;
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static void wdt_enable(void)
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{
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u32 reg;
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spin_lock(&wdt_lock);
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/* Set watchdog duration */
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writel(wdt_tclk * heartbeat, WDT_VAL);
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/* Clear watchdog timer interrupt */
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reg = readl(BRIDGE_CAUSE);
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reg &= ~WDT_INT_REQ;
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writel(reg, BRIDGE_CAUSE);
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/* Enable watchdog timer */
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reg = readl(TIMER_CTRL);
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reg |= WDT_EN;
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writel(reg, TIMER_CTRL);
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/* Enable reset on watchdog */
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reg = readl(CPU_RESET_MASK);
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reg |= WDT_RESET;
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writel(reg, CPU_RESET_MASK);
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spin_unlock(&wdt_lock);
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}
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static void wdt_disable(void)
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{
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u32 reg;
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spin_lock(&wdt_lock);
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/* Disable reset on watchdog */
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reg = readl(CPU_RESET_MASK);
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reg &= ~WDT_RESET;
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writel(reg, CPU_RESET_MASK);
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/* Disable watchdog timer */
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reg = readl(TIMER_CTRL);
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reg &= ~WDT_EN;
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writel(reg, TIMER_CTRL);
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spin_unlock(&wdt_lock);
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}
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static int orion5x_wdt_get_timeleft(int *time_left)
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{
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spin_lock(&wdt_lock);
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*time_left = readl(WDT_VAL) / wdt_tclk;
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spin_unlock(&wdt_lock);
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return 0;
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}
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static int orion5x_wdt_open(struct inode *inode, struct file *file)
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{
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if (test_and_set_bit(WDT_IN_USE, &wdt_status))
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return -EBUSY;
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clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
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wdt_enable();
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return nonseekable_open(inode, file);
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}
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static ssize_t orion5x_wdt_write(struct file *file, const char *data,
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size_t len, loff_t *ppos)
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{
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if (len) {
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if (!nowayout) {
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size_t i;
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clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
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for (i = 0; i != len; i++) {
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char c;
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if (get_user(c, data + i))
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return -EFAULT;
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if (c == 'V')
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set_bit(WDT_OK_TO_CLOSE, &wdt_status);
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}
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}
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wdt_enable();
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}
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return len;
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}
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static struct watchdog_info ident = {
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.options = WDIOF_MAGICCLOSE | WDIOF_SETTIMEOUT |
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WDIOF_KEEPALIVEPING,
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.identity = "Orion5x Watchdog",
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};
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static long orion5x_wdt_ioctl(struct file *file, unsigned int cmd,
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unsigned long arg)
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{
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int ret = -ENOTTY;
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int time;
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switch (cmd) {
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case WDIOC_GETSUPPORT:
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ret = copy_to_user((struct watchdog_info *)arg, &ident,
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sizeof(ident)) ? -EFAULT : 0;
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break;
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case WDIOC_GETSTATUS:
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case WDIOC_GETBOOTSTATUS:
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ret = put_user(0, (int *)arg);
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break;
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case WDIOC_KEEPALIVE:
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wdt_enable();
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ret = 0;
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break;
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case WDIOC_SETTIMEOUT:
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ret = get_user(time, (int *)arg);
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if (ret)
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break;
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if (time <= 0 || time > wdt_max_duration) {
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ret = -EINVAL;
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break;
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}
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heartbeat = time;
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wdt_enable();
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/* Fall through */
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case WDIOC_GETTIMEOUT:
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ret = put_user(heartbeat, (int *)arg);
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break;
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case WDIOC_GETTIMELEFT:
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if (orion5x_wdt_get_timeleft(&time)) {
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ret = -EINVAL;
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break;
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}
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ret = put_user(time, (int *)arg);
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break;
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}
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return ret;
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}
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static int orion5x_wdt_release(struct inode *inode, struct file *file)
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{
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if (test_bit(WDT_OK_TO_CLOSE, &wdt_status))
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wdt_disable();
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else
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printk(KERN_CRIT "WATCHDOG: Device closed unexpectedly - "
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"timer will not stop\n");
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clear_bit(WDT_IN_USE, &wdt_status);
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clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
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return 0;
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}
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static const struct file_operations orion5x_wdt_fops = {
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.owner = THIS_MODULE,
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.llseek = no_llseek,
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.write = orion5x_wdt_write,
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.unlocked_ioctl = orion5x_wdt_ioctl,
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.open = orion5x_wdt_open,
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.release = orion5x_wdt_release,
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};
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static struct miscdevice orion5x_wdt_miscdev = {
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.minor = WATCHDOG_MINOR,
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.name = "watchdog",
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.fops = &orion5x_wdt_fops,
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};
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static int __devinit orion5x_wdt_probe(struct platform_device *pdev)
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{
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struct orion5x_wdt_platform_data *pdata = pdev->dev.platform_data;
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int ret;
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if (pdata) {
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wdt_tclk = pdata->tclk;
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} else {
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printk(KERN_ERR "Orion5x Watchdog misses platform data\n");
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return -ENODEV;
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}
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if (orion5x_wdt_miscdev.parent)
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return -EBUSY;
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orion5x_wdt_miscdev.parent = &pdev->dev;
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wdt_max_duration = WDT_MAX_CYCLE_COUNT / wdt_tclk;
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if (heartbeat <= 0 || heartbeat > wdt_max_duration)
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heartbeat = wdt_max_duration;
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ret = misc_register(&orion5x_wdt_miscdev);
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if (ret)
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return ret;
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printk(KERN_INFO "Orion5x Watchdog Timer: Initial timeout %d sec%s\n",
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heartbeat, nowayout ? ", nowayout" : "");
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return 0;
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}
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static int __devexit orion5x_wdt_remove(struct platform_device *pdev)
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{
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int ret;
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if (test_bit(WDT_IN_USE, &wdt_status)) {
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wdt_disable();
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clear_bit(WDT_IN_USE, &wdt_status);
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}
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ret = misc_deregister(&orion5x_wdt_miscdev);
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if (!ret)
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orion5x_wdt_miscdev.parent = NULL;
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return ret;
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}
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static struct platform_driver orion5x_wdt_driver = {
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.probe = orion5x_wdt_probe,
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.remove = __devexit_p(orion5x_wdt_remove),
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.driver = {
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.owner = THIS_MODULE,
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.name = "orion5x_wdt",
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},
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};
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static int __init orion5x_wdt_init(void)
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{
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spin_lock_init(&wdt_lock);
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return platform_driver_register(&orion5x_wdt_driver);
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}
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static void __exit orion5x_wdt_exit(void)
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{
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platform_driver_unregister(&orion5x_wdt_driver);
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}
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module_init(orion5x_wdt_init);
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module_exit(orion5x_wdt_exit);
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MODULE_AUTHOR("Sylver Bruneau <sylver.bruneau@googlemail.com>");
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MODULE_DESCRIPTION("Orion5x Processor Watchdog");
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module_param(heartbeat, int, 0);
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MODULE_PARM_DESC(heartbeat, "Watchdog heartbeat in seconds");
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module_param(nowayout, int, 0);
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MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started");
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MODULE_LICENSE("GPL");
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MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
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