--- /dev/null
+/*
+ * Watchdog driver for Atmel AT32AP700X devices
+ *
+ * Copyright (C) 2005-2006 Atmel Corporation
+ *
+ * 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/init.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/miscdevice.h>
+#include <linux/fs.h>
+#include <linux/platform_device.h>
+#include <linux/watchdog.h>
+
+#include <asm/uaccess.h>
+#include <asm/io.h>
+
+#define TIMEOUT_MIN 1
+#define TIMEOUT_DEFAULT CONFIG_AT32AP700X_WDT_TIMEOUT
+#define TIMEOUT_MAX 2
+
+/* Watchdog registers and write/read macro */
+#define WDT_CTRL 0x00
+#define WDT_CTRL_EN 0
+#define WDT_CTRL_PSEL 8
+#define WDT_CTRL_KEY 24
+
+#define WDT_CLR 0x04
+
+#define WDT_BIT(name) (1 << WDT_##name)
+#define WDT_BF(name,value) ((value) << WDT_##name)
+
+#define wdt_readl(dev,reg) \
+ __raw_readl((dev)->regs + WDT_##reg)
+#define wdt_writel(dev,reg,value) \
+ __raw_writel((value), (dev)->regs + WDT_##reg)
+
+struct wdt_at32ap700x {
+ void __iomem *regs;
+ int timeout;
+ int users;
+ struct miscdevice miscdev;
+};
+
+static struct wdt_at32ap700x *wdt;
+
+/*
+ * Disable the watchdog.
+ */
+static void inline at32_wdt_stop(void)
+{
+ unsigned long psel = wdt_readl(wdt, CTRL) & WDT_BF(CTRL_PSEL, 0x0f);
+ wdt_writel(wdt, CTRL, psel | WDT_BF(CTRL_KEY, 0x55));
+ wdt_writel(wdt, CTRL, psel | WDT_BF(CTRL_KEY, 0xaa));
+}
+
+/*
+ * Enable and reset the watchdog.
+ */
+static void inline at32_wdt_start(void)
+{
+ /* 0xf is 2^16 divider = 2 sec, 0xe is 2^15 divider = 1 sec */
+ unsigned long psel = (wdt->timeout > 1) ? 0xf : 0xe;
+
+ wdt_writel(wdt, CTRL, WDT_BIT(CTRL_EN)
+ | WDT_BF(CTRL_PSEL, psel)
+ | WDT_BF(CTRL_KEY, 0x55));
+ wdt_writel(wdt, CTRL, WDT_BIT(CTRL_EN)
+ | WDT_BF(CTRL_PSEL, psel)
+ | WDT_BF(CTRL_KEY, 0xaa));
+}
+
+/*
+ * Pat the watchdog timer.
+ */
+static void inline at32_wdt_pat(void)
+{
+ wdt_writel(wdt, CLR, 0x42);
+}
+
+/*
+ * Watchdog device is opened, and watchdog starts running.
+ */
+static int at32_wdt_open(struct inode *inode, struct file *file)
+{
+ if (test_and_set_bit(1, &wdt->users))
+ return -EBUSY;
+
+ at32_wdt_start();
+ return nonseekable_open(inode, file);
+}
+
+/*
+ * Close the watchdog device. If CONFIG_WATCHDOG_NOWAYOUT is _not_ defined then
+ * the watchdog is also disabled.
+ */
+static int at32_wdt_close(struct inode *inode, struct file *file)
+{
+#ifndef CONFIG_WATCHDOG_NOWAYOUT
+ at32_wdt_stop();
+#endif
+ clear_bit(1, &wdt->users);
+ return 0;
+}
+
+/*
+ * Change the watchdog time interval.
+ */
+static int at32_wdt_settimeout(int time)
+{
+ /*
+ * All counting occurs at 1 / SLOW_CLOCK (32 kHz) and max prescaler is
+ * 2 ^ 16 allowing up to 2 seconds timeout.
+ */
+ if ((time < TIMEOUT_MIN) || (time > TIMEOUT_MAX))
+ return -EINVAL;
+
+ /* Set new watchdog time. It will be used when at32_wdt_start() is called. */
+ wdt->timeout = time;
+ return 0;
+}
+
+static struct watchdog_info at32_wdt_info = {
+ .identity = "at32ap700x watchdog",
+ .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
+};
+
+/*
+ * Handle commands from user-space.
+ */
+static int at32_wdt_ioctl(struct inode *inode, struct file *file,
+ unsigned int cmd, unsigned long arg)
+{
+ int ret = -ENOTTY;
+ int time;
+ void __user *argp = (void __user *)arg;
+ int __user *p = argp;
+
+ switch(cmd) {
+ case WDIOC_KEEPALIVE:
+ at32_wdt_pat();
+ ret = 0;
+ break;
+ case WDIOC_GETSUPPORT:
+ ret = copy_to_user(argp, &at32_wdt_info,
+ sizeof(at32_wdt_info)) ? -EFAULT : 0;
+ break;
+ case WDIOC_SETTIMEOUT:
+ ret = get_user(time, p);
+ if (ret)
+ break;
+ ret = at32_wdt_settimeout(time);
+ if (ret)
+ break;
+ /* Enable new time value */
+ at32_wdt_start();
+ /* fall through */
+ case WDIOC_GETTIMEOUT:
+ ret = put_user(wdt->timeout, p);
+ break;
+ case WDIOC_GETSTATUS: /* fall through */
+ case WDIOC_GETBOOTSTATUS:
+ ret = put_user(0, p);
+ break;
+ case WDIOC_SETOPTIONS:
+ ret = get_user(time, p);
+ if (ret)
+ break;
+ if (time & WDIOS_DISABLECARD)
+ at32_wdt_stop();
+ if (time & WDIOS_ENABLECARD)
+ at32_wdt_start();
+ ret = 0;
+ break;
+ }
+
+ return ret;
+}
+
+static ssize_t at32_wdt_write(struct file *file, const char *data, size_t len, loff_t *ppos)
+{
+ at32_wdt_pat();
+ return len;
+}
+
+static const struct file_operations at32_wdt_fops = {
+ .owner = THIS_MODULE,
+ .llseek = no_llseek,
+ .ioctl = at32_wdt_ioctl,
+ .open = at32_wdt_open,
+ .release = at32_wdt_close,
+ .write = at32_wdt_write,
+};
+
+static int __init at32_wdt_probe(struct platform_device *pdev)
+{
+ struct resource *regs;
+ int ret;
+
+ if (wdt) {
+ dev_dbg(&pdev->dev, "only 1 wdt instance supported.\n");
+ return -EBUSY;
+ }
+
+ regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ if (!regs) {
+ dev_dbg(&pdev->dev, "missing mmio resource\n");
+ return -ENXIO;
+ }
+
+ wdt = kzalloc(sizeof(struct wdt_at32ap700x), GFP_KERNEL);
+ if (!wdt) {
+ dev_dbg(&pdev->dev, "no memory for wdt structure\n");
+ return -ENOMEM;
+ }
+
+ wdt->regs = ioremap(regs->start, regs->end - regs->start + 1);
+ wdt->users = 0;
+ wdt->miscdev.minor = WATCHDOG_MINOR;
+ wdt->miscdev.name = "watchdog";
+ wdt->miscdev.fops = &at32_wdt_fops;
+
+ if (at32_wdt_settimeout(TIMEOUT_DEFAULT)) {
+ at32_wdt_settimeout(TIMEOUT_MAX);
+ dev_dbg(&pdev->dev,
+ "default timeout invalid, set to %d sec.\n",
+ TIMEOUT_MAX);
+ }
+
+ ret = misc_register(&wdt->miscdev);
+ if (ret) {
+ dev_dbg(&pdev->dev, "failed to register wdt miscdev\n");
+ goto err_register;
+ }
+
+ platform_set_drvdata(pdev, wdt);
+ wdt->miscdev.parent = &pdev->dev;
+ dev_info(&pdev->dev, "AT32AP700X WDT at 0x%p\n", wdt->regs);
+
+ return 0;
+
+err_register:
+ kfree(wdt);
+ wdt = NULL;
+ return ret;
+}
+
+static int __exit at32_wdt_remove(struct platform_device *pdev)
+{
+ if (wdt && platform_get_drvdata(pdev) == wdt) {
+ misc_deregister(&wdt->miscdev);
+ kfree(wdt);
+ wdt = NULL;
+ platform_set_drvdata(pdev, NULL);
+ }
+
+ return 0;
+}
+
+static void at32_wdt_shutdown(struct platform_device *pdev)
+{
+ at32_wdt_stop();
+}
+
+#ifdef CONFIG_PM
+static int at32_wdt_suspend(struct platform_device *pdev, pm_message_t message)
+{
+ at32_wdt_stop();
+ return 0;
+}
+
+static int at32_wdt_resume(struct platform_device *pdev)
+{
+ if (wdt->users)
+ at32_wdt_start();
+ return 0;
+}
+#endif
+
+static struct platform_driver at32_wdt_driver = {
+ .remove = __exit_p(at32_wdt_remove),
+#ifdef CONFIG_PM
+ .suspend = at32_wdt_suspend,
+ .resume = at32_wdt_resume,
+#endif
+ .driver = {
+ .name = "at32_wdt",
+ .owner = THIS_MODULE,
+ },
+ .shutdown = at32_wdt_shutdown,
+};
+
+static int __init at32_wdt_init(void)
+{
+ return platform_driver_probe(&at32_wdt_driver, at32_wdt_probe);
+}
+module_init(at32_wdt_init);
+
+static void __exit at32_wdt_exit(void)
+{
+ platform_driver_unregister(&at32_wdt_driver);
+}
+module_exit(at32_wdt_exit);
+
+MODULE_AUTHOR("Hans-Christian Egtvedt <hcegtvedt@atmel.com>");
+MODULE_DESCRIPTION("Watchdog driver for Atmel AT32AP700X");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
projects / linux-2.6 / commitdiff