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Diffstat (limited to 'kernel/drivers/watchdog/nuc900_wdt.c')
-rw-r--r--kernel/drivers/watchdog/nuc900_wdt.c308
1 files changed, 308 insertions, 0 deletions
diff --git a/kernel/drivers/watchdog/nuc900_wdt.c b/kernel/drivers/watchdog/nuc900_wdt.c
new file mode 100644
index 000000000..d5bed78c4
--- /dev/null
+++ b/kernel/drivers/watchdog/nuc900_wdt.c
@@ -0,0 +1,308 @@
+/*
+ * Copyright (c) 2009 Nuvoton technology corporation.
+ *
+ * Wan ZongShun <mcuos.com@gmail.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation;version 2 of the License.
+ *
+ */
+
+#include <linux/bitops.h>
+#include <linux/errno.h>
+#include <linux/fs.h>
+#include <linux/io.h>
+#include <linux/clk.h>
+#include <linux/kernel.h>
+#include <linux/miscdevice.h>
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+#include <linux/interrupt.h>
+#include <linux/types.h>
+#include <linux/watchdog.h>
+#include <linux/uaccess.h>
+
+#define REG_WTCR 0x1c
+#define WTCLK (0x01 << 10)
+#define WTE (0x01 << 7) /*wdt enable*/
+#define WTIS (0x03 << 4)
+#define WTIF (0x01 << 3)
+#define WTRF (0x01 << 2)
+#define WTRE (0x01 << 1)
+#define WTR (0x01 << 0)
+/*
+ * The watchdog time interval can be calculated via following formula:
+ * WTIS real time interval (formula)
+ * 0x00 ((2^ 14 ) * ((external crystal freq) / 256))seconds
+ * 0x01 ((2^ 16 ) * ((external crystal freq) / 256))seconds
+ * 0x02 ((2^ 18 ) * ((external crystal freq) / 256))seconds
+ * 0x03 ((2^ 20 ) * ((external crystal freq) / 256))seconds
+ *
+ * The external crystal freq is 15Mhz in the nuc900 evaluation board.
+ * So 0x00 = +-0.28 seconds, 0x01 = +-1.12 seconds, 0x02 = +-4.48 seconds,
+ * 0x03 = +- 16.92 seconds..
+ */
+#define WDT_HW_TIMEOUT 0x02
+#define WDT_TIMEOUT (HZ/2)
+#define WDT_HEARTBEAT 15
+
+static int heartbeat = WDT_HEARTBEAT;
+module_param(heartbeat, int, 0);
+MODULE_PARM_DESC(heartbeat, "Watchdog heartbeats in seconds. "
+ "(default = " __MODULE_STRING(WDT_HEARTBEAT) ")");
+
+static bool nowayout = WATCHDOG_NOWAYOUT;
+module_param(nowayout, bool, 0);
+MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started "
+ "(default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
+
+struct nuc900_wdt {
+ struct clk *wdt_clock;
+ struct platform_device *pdev;
+ void __iomem *wdt_base;
+ char expect_close;
+ struct timer_list timer;
+ spinlock_t wdt_lock;
+ unsigned long next_heartbeat;
+};
+
+static unsigned long nuc900wdt_busy;
+static struct nuc900_wdt *nuc900_wdt;
+
+static inline void nuc900_wdt_keepalive(void)
+{
+ unsigned int val;
+
+ spin_lock(&nuc900_wdt->wdt_lock);
+
+ val = __raw_readl(nuc900_wdt->wdt_base + REG_WTCR);
+ val |= (WTR | WTIF);
+ __raw_writel(val, nuc900_wdt->wdt_base + REG_WTCR);
+
+ spin_unlock(&nuc900_wdt->wdt_lock);
+}
+
+static inline void nuc900_wdt_start(void)
+{
+ unsigned int val;
+
+ spin_lock(&nuc900_wdt->wdt_lock);
+
+ val = __raw_readl(nuc900_wdt->wdt_base + REG_WTCR);
+ val |= (WTRE | WTE | WTR | WTCLK | WTIF);
+ val &= ~WTIS;
+ val |= (WDT_HW_TIMEOUT << 0x04);
+ __raw_writel(val, nuc900_wdt->wdt_base + REG_WTCR);
+
+ spin_unlock(&nuc900_wdt->wdt_lock);
+
+ nuc900_wdt->next_heartbeat = jiffies + heartbeat * HZ;
+ mod_timer(&nuc900_wdt->timer, jiffies + WDT_TIMEOUT);
+}
+
+static inline void nuc900_wdt_stop(void)
+{
+ unsigned int val;
+
+ del_timer(&nuc900_wdt->timer);
+
+ spin_lock(&nuc900_wdt->wdt_lock);
+
+ val = __raw_readl(nuc900_wdt->wdt_base + REG_WTCR);
+ val &= ~WTE;
+ __raw_writel(val, nuc900_wdt->wdt_base + REG_WTCR);
+
+ spin_unlock(&nuc900_wdt->wdt_lock);
+}
+
+static inline void nuc900_wdt_ping(void)
+{
+ nuc900_wdt->next_heartbeat = jiffies + heartbeat * HZ;
+}
+
+static int nuc900_wdt_open(struct inode *inode, struct file *file)
+{
+
+ if (test_and_set_bit(0, &nuc900wdt_busy))
+ return -EBUSY;
+
+ nuc900_wdt_start();
+
+ return nonseekable_open(inode, file);
+}
+
+static int nuc900_wdt_close(struct inode *inode, struct file *file)
+{
+ if (nuc900_wdt->expect_close == 42)
+ nuc900_wdt_stop();
+ else {
+ dev_crit(&nuc900_wdt->pdev->dev,
+ "Unexpected close, not stopping watchdog!\n");
+ nuc900_wdt_ping();
+ }
+
+ nuc900_wdt->expect_close = 0;
+ clear_bit(0, &nuc900wdt_busy);
+ return 0;
+}
+
+static const struct watchdog_info nuc900_wdt_info = {
+ .identity = "nuc900 watchdog",
+ .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING |
+ WDIOF_MAGICCLOSE,
+};
+
+static long nuc900_wdt_ioctl(struct file *file,
+ unsigned int cmd, unsigned long arg)
+{
+ void __user *argp = (void __user *)arg;
+ int __user *p = argp;
+ int new_value;
+
+ switch (cmd) {
+ case WDIOC_GETSUPPORT:
+ return copy_to_user(argp, &nuc900_wdt_info,
+ sizeof(nuc900_wdt_info)) ? -EFAULT : 0;
+ case WDIOC_GETSTATUS:
+ case WDIOC_GETBOOTSTATUS:
+ return put_user(0, p);
+
+ case WDIOC_KEEPALIVE:
+ nuc900_wdt_ping();
+ return 0;
+
+ case WDIOC_SETTIMEOUT:
+ if (get_user(new_value, p))
+ return -EFAULT;
+
+ heartbeat = new_value;
+ nuc900_wdt_ping();
+
+ return put_user(new_value, p);
+ case WDIOC_GETTIMEOUT:
+ return put_user(heartbeat, p);
+ default:
+ return -ENOTTY;
+ }
+}
+
+static ssize_t nuc900_wdt_write(struct file *file, const char __user *data,
+ size_t len, loff_t *ppos)
+{
+ if (!len)
+ return 0;
+
+ /* Scan for magic character */
+ if (!nowayout) {
+ size_t i;
+
+ nuc900_wdt->expect_close = 0;
+
+ for (i = 0; i < len; i++) {
+ char c;
+ if (get_user(c, data + i))
+ return -EFAULT;
+ if (c == 'V') {
+ nuc900_wdt->expect_close = 42;
+ break;
+ }
+ }
+ }
+
+ nuc900_wdt_ping();
+ return len;
+}
+
+static void nuc900_wdt_timer_ping(unsigned long data)
+{
+ if (time_before(jiffies, nuc900_wdt->next_heartbeat)) {
+ nuc900_wdt_keepalive();
+ mod_timer(&nuc900_wdt->timer, jiffies + WDT_TIMEOUT);
+ } else
+ dev_warn(&nuc900_wdt->pdev->dev, "Will reset the machine !\n");
+}
+
+static const struct file_operations nuc900wdt_fops = {
+ .owner = THIS_MODULE,
+ .llseek = no_llseek,
+ .unlocked_ioctl = nuc900_wdt_ioctl,
+ .open = nuc900_wdt_open,
+ .release = nuc900_wdt_close,
+ .write = nuc900_wdt_write,
+};
+
+static struct miscdevice nuc900wdt_miscdev = {
+ .minor = WATCHDOG_MINOR,
+ .name = "watchdog",
+ .fops = &nuc900wdt_fops,
+};
+
+static int nuc900wdt_probe(struct platform_device *pdev)
+{
+ struct resource *res;
+ int ret = 0;
+
+ nuc900_wdt = devm_kzalloc(&pdev->dev, sizeof(*nuc900_wdt),
+ GFP_KERNEL);
+ if (!nuc900_wdt)
+ return -ENOMEM;
+
+ nuc900_wdt->pdev = pdev;
+
+ spin_lock_init(&nuc900_wdt->wdt_lock);
+
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ nuc900_wdt->wdt_base = devm_ioremap_resource(&pdev->dev, res);
+ if (IS_ERR(nuc900_wdt->wdt_base))
+ return PTR_ERR(nuc900_wdt->wdt_base);
+
+ nuc900_wdt->wdt_clock = devm_clk_get(&pdev->dev, NULL);
+ if (IS_ERR(nuc900_wdt->wdt_clock)) {
+ dev_err(&pdev->dev, "failed to find watchdog clock source\n");
+ return PTR_ERR(nuc900_wdt->wdt_clock);
+ }
+
+ clk_enable(nuc900_wdt->wdt_clock);
+
+ setup_timer(&nuc900_wdt->timer, nuc900_wdt_timer_ping, 0);
+
+ ret = misc_register(&nuc900wdt_miscdev);
+ if (ret) {
+ dev_err(&pdev->dev, "err register miscdev on minor=%d (%d)\n",
+ WATCHDOG_MINOR, ret);
+ goto err_clk;
+ }
+
+ return 0;
+
+err_clk:
+ clk_disable(nuc900_wdt->wdt_clock);
+ return ret;
+}
+
+static int nuc900wdt_remove(struct platform_device *pdev)
+{
+ misc_deregister(&nuc900wdt_miscdev);
+
+ clk_disable(nuc900_wdt->wdt_clock);
+
+ return 0;
+}
+
+static struct platform_driver nuc900wdt_driver = {
+ .probe = nuc900wdt_probe,
+ .remove = nuc900wdt_remove,
+ .driver = {
+ .name = "nuc900-wdt",
+ },
+};
+
+module_platform_driver(nuc900wdt_driver);
+
+MODULE_AUTHOR("Wan ZongShun <mcuos.com@gmail.com>");
+MODULE_DESCRIPTION("Watchdog driver for NUC900");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:nuc900-wdt");