289 lines
6.3 KiB
C
289 lines
6.3 KiB
C
/*
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* Watchdog driver for Freescale STMP37XX/STMP378X
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*
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* Author: Vitaly Wool <vital@embeddedalley.com>
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*
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* Copyright 2008 Freescale Semiconductor, Inc. All Rights Reserved.
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* Copyright 2008 Embedded Alley Solutions, Inc All Rights Reserved.
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*/
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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#include <linux/init.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/watchdog.h>
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#include <linux/platform_device.h>
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#include <linux/spinlock.h>
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#include <linux/uaccess.h>
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#include <linux/module.h>
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#include <mach/platform.h>
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#include <mach/regs-rtc.h>
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#define DEFAULT_HEARTBEAT 19
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#define MAX_HEARTBEAT (0x10000000 >> 6)
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/* missing bitmask in headers */
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#define BV_RTC_PERSISTENT1_GENERAL__RTC_FORCE_UPDATER 0x80000000
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#define WDT_IN_USE 0
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#define WDT_OK_TO_CLOSE 1
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#define WDOG_COUNTER_RATE 1000 /* 1 kHz clock */
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static DEFINE_SPINLOCK(stmp3xxx_wdt_io_lock);
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static unsigned long wdt_status;
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static const bool nowayout = WATCHDOG_NOWAYOUT;
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static int heartbeat = DEFAULT_HEARTBEAT;
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static unsigned long boot_status;
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static void wdt_enable(u32 value)
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{
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spin_lock(&stmp3xxx_wdt_io_lock);
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__raw_writel(value, REGS_RTC_BASE + HW_RTC_WATCHDOG);
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stmp3xxx_setl(BM_RTC_CTRL_WATCHDOGEN, REGS_RTC_BASE + HW_RTC_CTRL);
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stmp3xxx_setl(BV_RTC_PERSISTENT1_GENERAL__RTC_FORCE_UPDATER,
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REGS_RTC_BASE + HW_RTC_PERSISTENT1);
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spin_unlock(&stmp3xxx_wdt_io_lock);
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}
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static void wdt_disable(void)
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{
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spin_lock(&stmp3xxx_wdt_io_lock);
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stmp3xxx_clearl(BV_RTC_PERSISTENT1_GENERAL__RTC_FORCE_UPDATER,
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REGS_RTC_BASE + HW_RTC_PERSISTENT1);
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stmp3xxx_clearl(BM_RTC_CTRL_WATCHDOGEN, REGS_RTC_BASE + HW_RTC_CTRL);
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spin_unlock(&stmp3xxx_wdt_io_lock);
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}
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static void wdt_ping(void)
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{
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wdt_enable(heartbeat * WDOG_COUNTER_RATE);
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}
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static int stmp3xxx_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_ping();
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return nonseekable_open(inode, file);
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}
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static ssize_t stmp3xxx_wdt_write(struct file *file, const char __user *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_ping();
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}
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return len;
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}
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static const struct watchdog_info ident = {
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.options = WDIOF_CARDRESET |
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WDIOF_MAGICCLOSE |
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WDIOF_SETTIMEOUT |
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WDIOF_KEEPALIVEPING,
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.identity = "STMP3XXX Watchdog",
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};
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static long stmp3xxx_wdt_ioctl(struct file *file, unsigned int cmd,
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unsigned long arg)
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{
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void __user *argp = (void __user *)arg;
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int __user *p = argp;
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int new_heartbeat, opts;
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int ret = -ENOTTY;
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switch (cmd) {
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case WDIOC_GETSUPPORT:
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ret = copy_to_user(argp, &ident, sizeof(ident)) ? -EFAULT : 0;
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break;
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case WDIOC_GETSTATUS:
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ret = put_user(0, p);
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break;
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case WDIOC_GETBOOTSTATUS:
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ret = put_user(boot_status, p);
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break;
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case WDIOC_SETOPTIONS:
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if (get_user(opts, p)) {
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ret = -EFAULT;
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break;
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}
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if (opts & WDIOS_DISABLECARD)
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wdt_disable();
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else if (opts & WDIOS_ENABLECARD)
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wdt_ping();
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else {
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pr_debug("%s: unknown option 0x%x\n", __func__, opts);
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ret = -EINVAL;
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break;
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}
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ret = 0;
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break;
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case WDIOC_KEEPALIVE:
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wdt_ping();
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ret = 0;
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break;
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case WDIOC_SETTIMEOUT:
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if (get_user(new_heartbeat, p)) {
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ret = -EFAULT;
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break;
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}
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if (new_heartbeat <= 0 || new_heartbeat > MAX_HEARTBEAT) {
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ret = -EINVAL;
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break;
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}
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heartbeat = new_heartbeat;
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wdt_ping();
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/* Fall through */
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case WDIOC_GETTIMEOUT:
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ret = put_user(heartbeat, p);
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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 stmp3xxx_wdt_release(struct inode *inode, struct file *file)
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{
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int ret = 0;
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if (!nowayout) {
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if (!test_bit(WDT_OK_TO_CLOSE, &wdt_status)) {
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wdt_ping();
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pr_debug("%s: Device closed unexpectedly\n", __func__);
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ret = -EINVAL;
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} else {
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wdt_disable();
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clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
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}
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}
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clear_bit(WDT_IN_USE, &wdt_status);
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return ret;
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}
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static const struct file_operations stmp3xxx_wdt_fops = {
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.owner = THIS_MODULE,
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.llseek = no_llseek,
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.write = stmp3xxx_wdt_write,
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.unlocked_ioctl = stmp3xxx_wdt_ioctl,
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.open = stmp3xxx_wdt_open,
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.release = stmp3xxx_wdt_release,
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};
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static struct miscdevice stmp3xxx_wdt_miscdev = {
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.minor = WATCHDOG_MINOR,
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.name = "watchdog",
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.fops = &stmp3xxx_wdt_fops,
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};
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static int stmp3xxx_wdt_probe(struct platform_device *pdev)
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{
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int ret = 0;
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if (heartbeat < 1 || heartbeat > MAX_HEARTBEAT)
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heartbeat = DEFAULT_HEARTBEAT;
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boot_status = __raw_readl(REGS_RTC_BASE + HW_RTC_PERSISTENT1) &
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BV_RTC_PERSISTENT1_GENERAL__RTC_FORCE_UPDATER;
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boot_status = !!boot_status;
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stmp3xxx_clearl(BV_RTC_PERSISTENT1_GENERAL__RTC_FORCE_UPDATER,
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REGS_RTC_BASE + HW_RTC_PERSISTENT1);
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wdt_disable(); /* disable for now */
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ret = misc_register(&stmp3xxx_wdt_miscdev);
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if (ret < 0) {
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dev_err(&pdev->dev, "cannot register misc device\n");
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return ret;
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}
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pr_info("initialized, heartbeat %d sec\n", heartbeat);
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return ret;
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}
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static int stmp3xxx_wdt_remove(struct platform_device *pdev)
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{
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misc_deregister(&stmp3xxx_wdt_miscdev);
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return 0;
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}
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#ifdef CONFIG_PM
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static int wdt_suspended;
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static u32 wdt_saved_time;
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static int stmp3xxx_wdt_suspend(struct platform_device *pdev,
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pm_message_t state)
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{
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if (__raw_readl(REGS_RTC_BASE + HW_RTC_CTRL) &
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BM_RTC_CTRL_WATCHDOGEN) {
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wdt_suspended = 1;
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wdt_saved_time = __raw_readl(REGS_RTC_BASE + HW_RTC_WATCHDOG);
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wdt_disable();
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}
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return 0;
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}
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static int stmp3xxx_wdt_resume(struct platform_device *pdev)
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{
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if (wdt_suspended) {
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wdt_enable(wdt_saved_time);
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wdt_suspended = 0;
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}
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return 0;
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}
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#else
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#define stmp3xxx_wdt_suspend NULL
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#define stmp3xxx_wdt_resume NULL
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#endif
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static struct platform_driver platform_wdt_driver = {
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.driver = {
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.name = "stmp3xxx_wdt",
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},
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.probe = stmp3xxx_wdt_probe,
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.remove = stmp3xxx_wdt_remove,
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.suspend = stmp3xxx_wdt_suspend,
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.resume = stmp3xxx_wdt_resume,
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};
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module_platform_driver(platform_wdt_driver);
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MODULE_DESCRIPTION("STMP3XXX Watchdog Driver");
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MODULE_LICENSE("GPL");
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module_param(heartbeat, int, 0);
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MODULE_PARM_DESC(heartbeat,
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"Watchdog heartbeat period in seconds from 1 to "
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__MODULE_STRING(MAX_HEARTBEAT) ", default "
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__MODULE_STRING(DEFAULT_HEARTBEAT));
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MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
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