--- /dev/null
+/*
+ * Ralink RT288X/RT305X built-in hardware watchdog timer
+ *
+ * Copyright (C) 2011 Gabor Juhos <juhosg@openwrt.org>
+ *
+ * This driver was based on: drivers/watchdog/ixp4xx_wdt.c
+ * Author: Deepak Saxena <dsaxena@plexity.net>
+ * Copyright 2004 (c) MontaVista, Software, Inc.
+ *
+ * which again was based on sa1100 driver,
+ * Copyright (C) 2000 Oleg Drokin <green@crimea.edu>
+ *
+ * parts of the driver are based on Ralink's 2.6.21 BSP
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 as published
+ * by the Free Software Foundation.
+ */
+
+#include <linux/bitops.h>
+#include <linux/errno.h>
+#include <linux/fs.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/miscdevice.h>
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/platform_device.h>
+#include <linux/types.h>
+#include <linux/watchdog.h>
+#include <linux/clk.h>
+#include <linux/err.h>
+
+#define DRIVER_NAME "ramips-wdt"
+
+#define RAMIPS_WDT_TIMEOUT 20 /* seconds */
+#define RAMIPS_WDT_PRESCALE 65536
+
+#define TIMER_REG_TMRSTAT 0x00
+#define TIMER_REG_TMR1LOAD 0x20
+#define TIMER_REG_TMR1CTL 0x28
+
+#define TMRSTAT_TMR1RST BIT(5)
+
+#define TMR1CTL_ENABLE BIT(7)
+#define TMR1CTL_MODE_SHIFT 4
+#define TMR1CTL_MODE_MASK 0x3
+#define TMR1CTL_MODE_FREE_RUNNING 0x0
+#define TMR1CTL_MODE_PERIODIC 0x1
+#define TMR1CTL_MODE_TIMEOUT 0x2
+#define TMR1CTL_MODE_WDT 0x3
+#define TMR1CTL_PRESCALE_MASK 0xf
+#define TMR1CTL_PRESCALE_65536 0xf
+
+static int nowayout = WATCHDOG_NOWAYOUT;
+module_param(nowayout, int, 0);
+MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started "
+ "(default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
+
+static int ramips_wdt_timeout = RAMIPS_WDT_TIMEOUT;
+module_param_named(timeout, ramips_wdt_timeout, int, 0);
+MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds "
+ "(default=" __MODULE_STRING(RAMIPS_WDT_TIMEOUT) "s)");
+
+static unsigned long ramips_wdt_flags;
+
+#define WDT_FLAGS_BUSY 0
+#define WDT_FLAGS_EXPECT_CLOSE 1
+
+static struct clk *ramips_wdt_clk;
+static unsigned long ramips_wdt_freq;
+static int ramips_wdt_max_timeout;
+static void __iomem *ramips_wdt_base;
+
+static inline void ramips_wdt_wr(unsigned reg, u32 val)
+{
+ __raw_writel(val, ramips_wdt_base + reg);
+}
+
+static inline u32 ramips_wdt_rr(unsigned reg)
+{
+ return __raw_readl(ramips_wdt_base + reg);
+}
+
+static inline void ramips_wdt_keepalive(void)
+{
+ ramips_wdt_wr(TIMER_REG_TMR1LOAD, ramips_wdt_timeout * ramips_wdt_freq);
+}
+
+static inline void ramips_wdt_enable(void)
+{
+ u32 t;
+
+ ramips_wdt_keepalive();
+
+ t = ramips_wdt_rr(TIMER_REG_TMR1CTL);
+ t |= TMR1CTL_ENABLE;
+ ramips_wdt_wr(TIMER_REG_TMR1CTL, t);
+}
+
+static inline void ramips_wdt_disable(void)
+{
+ u32 t;
+
+ ramips_wdt_keepalive();
+
+ t = ramips_wdt_rr(TIMER_REG_TMR1CTL);
+ t &= ~TMR1CTL_ENABLE;
+ ramips_wdt_wr(TIMER_REG_TMR1CTL, t);
+}
+
+static int ramips_wdt_set_timeout(int val)
+{
+ if (val < 1 || val > ramips_wdt_max_timeout) {
+ pr_crit(DRIVER_NAME
+ ": timeout value %d must be 0 < timeout < %d\n",
+ val, ramips_wdt_max_timeout);
+ return -EINVAL;
+ }
+
+ ramips_wdt_timeout = val;
+ ramips_wdt_keepalive();
+
+ return 0;
+}
+
+static int ramips_wdt_open(struct inode *inode, struct file *file)
+{
+ u32 t;
+
+ if (test_and_set_bit(WDT_FLAGS_BUSY, &ramips_wdt_flags))
+ return -EBUSY;
+
+ clear_bit(WDT_FLAGS_EXPECT_CLOSE, &ramips_wdt_flags);
+
+ t = ramips_wdt_rr(TIMER_REG_TMR1CTL);
+ t &= ~(TMR1CTL_MODE_MASK << TMR1CTL_MODE_SHIFT |
+ TMR1CTL_PRESCALE_MASK);
+ t |= (TMR1CTL_MODE_WDT << TMR1CTL_MODE_SHIFT |
+ TMR1CTL_PRESCALE_65536);
+ ramips_wdt_wr(TIMER_REG_TMR1CTL, t);
+
+ ramips_wdt_enable();
+
+ return nonseekable_open(inode, file);
+}
+
+static int ramips_wdt_release(struct inode *inode, struct file *file)
+{
+ if (test_bit(WDT_FLAGS_EXPECT_CLOSE, &ramips_wdt_flags))
+ ramips_wdt_disable();
+ else {
+ pr_crit(DRIVER_NAME ": device closed unexpectedly, "
+ "watchdog timer will not stop!\n");
+ ramips_wdt_keepalive();
+ }
+
+ clear_bit(WDT_FLAGS_BUSY, &ramips_wdt_flags);
+ clear_bit(WDT_FLAGS_EXPECT_CLOSE, &ramips_wdt_flags);
+
+ return 0;
+}
+
+static ssize_t ramips_wdt_write(struct file *file, const char *data,
+ size_t len, loff_t *ppos)
+{
+ if (len) {
+ if (!nowayout) {
+ size_t i;
+
+ clear_bit(WDT_FLAGS_EXPECT_CLOSE, &ramips_wdt_flags);
+
+ for (i = 0; i != len; i++) {
+ char c;
+
+ if (get_user(c, data + i))
+ return -EFAULT;
+
+ if (c == 'V')
+ set_bit(WDT_FLAGS_EXPECT_CLOSE,
+ &ramips_wdt_flags);
+ }
+ }
+
+ ramips_wdt_keepalive();
+ }
+
+ return len;
+}
+
+static const struct watchdog_info ramips_wdt_info = {
+ .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING |
+ WDIOF_MAGICCLOSE,
+ .firmware_version = 0,
+ .identity = "RAMIPS watchdog",
+};
+
+static long ramips_wdt_ioctl(struct file *file, unsigned int cmd,
+ unsigned long arg)
+{
+ void __user *argp = (void __user *)arg;
+ int __user *p = argp;
+ int err;
+ int t;
+
+ switch (cmd) {
+ case WDIOC_GETSUPPORT:
+ err = copy_to_user(argp, &ramips_wdt_info,
+ sizeof(ramips_wdt_info)) ? -EFAULT : 0;
+ break;
+
+ case WDIOC_GETSTATUS:
+ err = put_user(0, p);
+ break;
+
+ case WDIOC_KEEPALIVE:
+ ramips_wdt_keepalive();
+ err = 0;
+ break;
+
+ case WDIOC_SETTIMEOUT:
+ err = get_user(t, p);
+ if (err)
+ break;
+
+ err = ramips_wdt_set_timeout(t);
+ if (err)
+ break;
+
+ /* fallthrough */
+ case WDIOC_GETTIMEOUT:
+ err = put_user(ramips_wdt_timeout, p);
+ break;
+
+ default:
+ err = -ENOTTY;
+ break;
+ }
+
+ return err;
+}
+
+static const struct file_operations ramips_wdt_fops = {
+ .owner = THIS_MODULE,
+ .llseek = no_llseek,
+ .write = ramips_wdt_write,
+ .unlocked_ioctl = ramips_wdt_ioctl,
+ .open = ramips_wdt_open,
+ .release = ramips_wdt_release,
+};
+
+static struct miscdevice ramips_wdt_miscdev = {
+ .minor = WATCHDOG_MINOR,
+ .name = "watchdog",
+ .fops = &ramips_wdt_fops,
+};
+
+static int __devinit ramips_wdt_probe(struct platform_device *pdev)
+{
+ struct resource *res;
+ int err;
+
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ if (!res) {
+ dev_err(&pdev->dev, "no memory resource found\n");
+ return -EINVAL;
+ }
+
+ ramips_wdt_base = ioremap(res->start, resource_size(res));
+ if (!ramips_wdt_base)
+ return -ENOMEM;
+
+ ramips_wdt_clk = clk_get(&pdev->dev, "wdt");
+ if (IS_ERR(ramips_wdt_clk)) {
+ err = PTR_ERR(ramips_wdt_clk);
+ goto err_unmap;
+ }
+
+ err = clk_enable(ramips_wdt_clk);
+ if (err)
+ goto err_clk_put;
+
+ ramips_wdt_freq = clk_get_rate(ramips_wdt_clk) / RAMIPS_WDT_PRESCALE;
+ if (!ramips_wdt_freq) {
+ err = -EINVAL;
+ goto err_clk_disable;
+ }
+
+ ramips_wdt_max_timeout = (0xfffful / ramips_wdt_freq);
+ if (ramips_wdt_timeout < 1 ||
+ ramips_wdt_timeout > ramips_wdt_max_timeout) {
+ ramips_wdt_timeout = ramips_wdt_max_timeout;
+ dev_info(&pdev->dev,
+ "timeout value must be 0 < timeout < %d, using %d\n",
+ ramips_wdt_max_timeout, ramips_wdt_timeout);
+ }
+
+ err = misc_register(&ramips_wdt_miscdev);
+ if (err) {
+ dev_err(&pdev->dev,
+ "unable to register misc device, err=%d\n", err);
+ goto err_clk_disable;
+ }
+
+ return 0;
+
+err_clk_disable:
+ clk_disable(ramips_wdt_clk);
+err_clk_put:
+ clk_put(ramips_wdt_clk);
+err_unmap:
+ iounmap(ramips_wdt_base);
+ return err;
+}
+
+static int __devexit ramips_wdt_remove(struct platform_device *pdev)
+{
+ misc_deregister(&ramips_wdt_miscdev);
+ clk_disable(ramips_wdt_clk);
+ clk_put(ramips_wdt_clk);
+ iounmap(ramips_wdt_base);
+ return 0;
+}
+
+static void ramips_wdt_shutdown(struct platform_device *pdev)
+{
+ ramips_wdt_disable();
+}
+
+static struct platform_driver ramips_wdt_driver = {
+ .remove = __devexit_p(ramips_wdt_remove),
+ .shutdown = ramips_wdt_shutdown,
+ .driver = {
+ .name = DRIVER_NAME,
+ .owner = THIS_MODULE,
+ },
+};
+
+static int __init ramips_wdt_init(void)
+{
+ return platform_driver_probe(&ramips_wdt_driver, ramips_wdt_probe);
+}
+module_init(ramips_wdt_init);
+
+static void __exit ramips_wdt_exit(void)
+{
+ platform_driver_unregister(&ramips_wdt_driver);
+}
+module_exit(ramips_wdt_exit);
+
+MODULE_DESCRIPTION("Ralink RT288X/RT305X hardware watchdog driver");
+MODULE_AUTHOR("Gabor Juhos <juhosg@openwrt.org");
+MODULE_LICENSE("GPL v2");
+MODULE_ALIAS("platform:" DRIVER_NAME);
+MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
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