aboutsummaryrefslogtreecommitdiff
path: root/drivers/char/watchdog/at32ap700x_wdt.c
diff options
context:
space:
mode:
Diffstat (limited to 'drivers/char/watchdog/at32ap700x_wdt.c')
-rw-r--r--drivers/char/watchdog/at32ap700x_wdt.c386
1 files changed, 386 insertions, 0 deletions
diff --git a/drivers/char/watchdog/at32ap700x_wdt.c b/drivers/char/watchdog/at32ap700x_wdt.c
new file mode 100644
index 00000000000..54a516169d0
--- /dev/null
+++ b/drivers/char/watchdog/at32ap700x_wdt.c
@@ -0,0 +1,386 @@
+/*
+ * 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 <linux/uaccess.h>
+#include <linux/io.h>
+#include <linux/spinlock.h>
+
+#define TIMEOUT_MIN 1
+#define TIMEOUT_MAX 2
+#define TIMEOUT_DEFAULT TIMEOUT_MAX
+
+/* module parameters */
+static int timeout = TIMEOUT_DEFAULT;
+module_param(timeout, int, 0);
+MODULE_PARM_DESC(timeout,
+ "Timeout value. Limited to be 1 or 2 seconds. (default="
+ __MODULE_STRING(TIMEOUT_DEFAULT) ")");
+
+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) ")");
+
+/* 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;
+ spinlock_t io_lock;
+ int timeout;
+ unsigned long users;
+ struct miscdevice miscdev;
+};
+
+static struct wdt_at32ap700x *wdt;
+static char expect_release;
+
+/*
+ * Disable the watchdog.
+ */
+static inline void at32_wdt_stop(void)
+{
+ unsigned long psel;
+
+ spin_lock(&wdt->io_lock);
+ 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));
+ spin_unlock(&wdt->io_lock);
+}
+
+/*
+ * Enable and reset the watchdog.
+ */
+static inline void 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;
+
+ spin_lock(&wdt->io_lock);
+ 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));
+ spin_unlock(&wdt->io_lock);
+}
+
+/*
+ * Pat the watchdog timer.
+ */
+static inline void at32_wdt_pat(void)
+{
+ spin_lock(&wdt->io_lock);
+ wdt_writel(wdt, CLR, 0x42);
+ spin_unlock(&wdt->io_lock);
+}
+
+/*
+ * 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.
+ */
+static int at32_wdt_close(struct inode *inode, struct file *file)
+{
+ if (expect_release == 42) {
+ at32_wdt_stop();
+ } else {
+ dev_dbg(wdt->miscdev.parent,
+ "Unexpected close, not stopping watchdog!\n");
+ at32_wdt_pat();
+ }
+ clear_bit(1, &wdt->users);
+ expect_release = 0;
+ 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 |
+ WDIOF_MAGICCLOSE,
+};
+
+/*
+ * 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 __user *data,
+ size_t len, loff_t *ppos)
+{
+ /* See if we got the magic character 'V' and reload the timer */
+ if (len) {
+ if (!nowayout) {
+ size_t i;
+
+ /*
+ * note: just in case someone wrote the magic
+ * character five months ago...
+ */
+ expect_release = 0;
+
+ /*
+ * scan to see whether or not we got the magic
+ * character
+ */
+ for (i = 0; i != len; i++) {
+ char c;
+ if (get_user(c, data+i))
+ return -EFAULT;
+ if (c == 'V')
+ expect_release = 42;
+ }
+ }
+ /* someone wrote to us, we should pat the watchdog */
+ 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);
+ if (!wdt->regs) {
+ ret = -ENOMEM;
+ dev_dbg(&pdev->dev, "could not map I/O memory\n");
+ goto err_free;
+ }
+ spin_lock_init(&wdt->io_lock);
+ wdt->users = 0;
+ wdt->miscdev.minor = WATCHDOG_MINOR;
+ wdt->miscdev.name = "watchdog";
+ wdt->miscdev.fops = &at32_wdt_fops;
+
+ if (at32_wdt_settimeout(timeout)) {
+ at32_wdt_settimeout(TIMEOUT_DEFAULT);
+ dev_dbg(&pdev->dev,
+ "default timeout invalid, set to %d sec.\n",
+ TIMEOUT_DEFAULT);
+ }
+
+ ret = misc_register(&wdt->miscdev);
+ if (ret) {
+ dev_dbg(&pdev->dev, "failed to register wdt miscdev\n");
+ goto err_iounmap;
+ }
+
+ platform_set_drvdata(pdev, wdt);
+ wdt->miscdev.parent = &pdev->dev;
+ dev_info(&pdev->dev,
+ "AT32AP700X WDT at 0x%p, timeout %d sec (nowayout=%d)\n",
+ wdt->regs, wdt->timeout, nowayout);
+
+ return 0;
+
+err_iounmap:
+ iounmap(wdt->regs);
+err_free:
+ kfree(wdt);
+ wdt = NULL;
+ return ret;
+}
+
+static int __exit at32_wdt_remove(struct platform_device *pdev)
+{
+ if (wdt && platform_get_drvdata(pdev) == wdt) {
+ /* Stop the timer before we leave */
+ if (!nowayout)
+ at32_wdt_stop();
+
+ misc_deregister(&wdt->miscdev);
+ iounmap(wdt->regs);
+ 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;
+}
+#else
+#define at32_wdt_suspend NULL
+#define at32_wdt_resume NULL
+#endif
+
+static struct platform_driver at32_wdt_driver = {
+ .remove = __exit_p(at32_wdt_remove),
+ .suspend = at32_wdt_suspend,
+ .resume = at32_wdt_resume,
+ .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);