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path: root/drivers/watchdog/txx9wdt.c
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-rw-r--r--drivers/watchdog/txx9wdt.c276
1 files changed, 276 insertions, 0 deletions
diff --git a/drivers/watchdog/txx9wdt.c b/drivers/watchdog/txx9wdt.c
new file mode 100644
index 000000000000..328b3c7211ef
--- /dev/null
+++ b/drivers/watchdog/txx9wdt.c
@@ -0,0 +1,276 @@
+/*
+ * txx9wdt: A Hardware Watchdog Driver for TXx9 SoCs
+ *
+ * Copyright (C) 2007 Atsushi Nemoto <anemo@mba.ocn.ne.jp>
+ *
+ * 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/module.h>
+#include <linux/moduleparam.h>
+#include <linux/types.h>
+#include <linux/miscdevice.h>
+#include <linux/watchdog.h>
+#include <linux/fs.h>
+#include <linux/reboot.h>
+#include <linux/init.h>
+#include <linux/uaccess.h>
+#include <linux/platform_device.h>
+#include <linux/clk.h>
+#include <linux/err.h>
+#include <linux/io.h>
+#include <asm/txx9tmr.h>
+
+#define TIMER_MARGIN 60 /* Default is 60 seconds */
+
+static int timeout = TIMER_MARGIN; /* in seconds */
+module_param(timeout, int, 0);
+MODULE_PARM_DESC(timeout,
+ "Watchdog timeout in seconds. "
+ "(0<timeout<((2^" __MODULE_STRING(TXX9_TIMER_BITS) ")/(IMCLK/256)), "
+ "default=" __MODULE_STRING(TIMER_MARGIN) ")");
+
+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) ")");
+
+#define WD_TIMER_CCD 7 /* 1/256 */
+#define WD_TIMER_CLK (clk_get_rate(txx9_imclk) / (2 << WD_TIMER_CCD))
+#define WD_MAX_TIMEOUT ((0xffffffff >> (32 - TXX9_TIMER_BITS)) / WD_TIMER_CLK)
+
+static unsigned long txx9wdt_alive;
+static int expect_close;
+static struct txx9_tmr_reg __iomem *txx9wdt_reg;
+static struct clk *txx9_imclk;
+
+static void txx9wdt_ping(void)
+{
+ __raw_writel(TXx9_TMWTMR_TWIE | TXx9_TMWTMR_TWC, &txx9wdt_reg->wtmr);
+}
+
+static void txx9wdt_start(void)
+{
+ __raw_writel(WD_TIMER_CLK * timeout, &txx9wdt_reg->cpra);
+ __raw_writel(WD_TIMER_CCD, &txx9wdt_reg->ccdr);
+ __raw_writel(0, &txx9wdt_reg->tisr); /* clear pending interrupt */
+ __raw_writel(TXx9_TMTCR_TCE | TXx9_TMTCR_CCDE | TXx9_TMTCR_TMODE_WDOG,
+ &txx9wdt_reg->tcr);
+ __raw_writel(TXx9_TMWTMR_TWIE | TXx9_TMWTMR_TWC, &txx9wdt_reg->wtmr);
+}
+
+static void txx9wdt_stop(void)
+{
+ __raw_writel(TXx9_TMWTMR_WDIS, &txx9wdt_reg->wtmr);
+ __raw_writel(__raw_readl(&txx9wdt_reg->tcr) & ~TXx9_TMTCR_TCE,
+ &txx9wdt_reg->tcr);
+}
+
+static int txx9wdt_open(struct inode *inode, struct file *file)
+{
+ if (test_and_set_bit(0, &txx9wdt_alive))
+ return -EBUSY;
+
+ if (__raw_readl(&txx9wdt_reg->tcr) & TXx9_TMTCR_TCE) {
+ clear_bit(0, &txx9wdt_alive);
+ return -EBUSY;
+ }
+
+ if (nowayout)
+ __module_get(THIS_MODULE);
+
+ txx9wdt_start();
+ return nonseekable_open(inode, file);
+}
+
+static int txx9wdt_release(struct inode *inode, struct file *file)
+{
+ if (expect_close)
+ txx9wdt_stop();
+ else {
+ printk(KERN_CRIT "txx9wdt: "
+ "Unexpected close, not stopping watchdog!\n");
+ txx9wdt_ping();
+ }
+ clear_bit(0, &txx9wdt_alive);
+ expect_close = 0;
+ return 0;
+}
+
+static ssize_t txx9wdt_write(struct file *file, const char __user *data,
+ size_t len, loff_t *ppos)
+{
+ if (len) {
+ if (!nowayout) {
+ size_t i;
+
+ expect_close = 0;
+ for (i = 0; i != len; i++) {
+ char c;
+ if (get_user(c, data + i))
+ return -EFAULT;
+ if (c == 'V')
+ expect_close = 1;
+ }
+ }
+ txx9wdt_ping();
+ }
+ return len;
+}
+
+static int txx9wdt_ioctl(struct inode *inode, struct file *file,
+ unsigned int cmd, unsigned long arg)
+{
+ void __user *argp = (void __user *)arg;
+ int __user *p = argp;
+ int new_timeout;
+ static struct watchdog_info ident = {
+ .options = WDIOF_SETTIMEOUT |
+ WDIOF_KEEPALIVEPING |
+ WDIOF_MAGICCLOSE,
+ .firmware_version = 0,
+ .identity = "Hardware Watchdog for TXx9",
+ };
+
+ switch (cmd) {
+ default:
+ return -ENOTTY;
+ case WDIOC_GETSUPPORT:
+ return copy_to_user(argp, &ident, sizeof(ident)) ? -EFAULT : 0;
+ case WDIOC_GETSTATUS:
+ case WDIOC_GETBOOTSTATUS:
+ return put_user(0, p);
+ case WDIOC_KEEPALIVE:
+ txx9wdt_ping();
+ return 0;
+ case WDIOC_SETTIMEOUT:
+ if (get_user(new_timeout, p))
+ return -EFAULT;
+ if (new_timeout < 1 || new_timeout > WD_MAX_TIMEOUT)
+ return -EINVAL;
+ timeout = new_timeout;
+ txx9wdt_stop();
+ txx9wdt_start();
+ /* Fall */
+ case WDIOC_GETTIMEOUT:
+ return put_user(timeout, p);
+ }
+}
+
+static int txx9wdt_notify_sys(struct notifier_block *this, unsigned long code,
+ void *unused)
+{
+ if (code == SYS_DOWN || code == SYS_HALT)
+ txx9wdt_stop();
+ return NOTIFY_DONE;
+}
+
+static const struct file_operations txx9wdt_fops = {
+ .owner = THIS_MODULE,
+ .llseek = no_llseek,
+ .write = txx9wdt_write,
+ .ioctl = txx9wdt_ioctl,
+ .open = txx9wdt_open,
+ .release = txx9wdt_release,
+};
+
+static struct miscdevice txx9wdt_miscdev = {
+ .minor = WATCHDOG_MINOR,
+ .name = "watchdog",
+ .fops = &txx9wdt_fops,
+};
+
+static struct notifier_block txx9wdt_notifier = {
+ .notifier_call = txx9wdt_notify_sys
+};
+
+static int __init txx9wdt_probe(struct platform_device *dev)
+{
+ struct resource *res;
+ int ret;
+
+ txx9_imclk = clk_get(NULL, "imbus_clk");
+ if (IS_ERR(txx9_imclk)) {
+ ret = PTR_ERR(txx9_imclk);
+ txx9_imclk = NULL;
+ goto exit;
+ }
+ ret = clk_enable(txx9_imclk);
+ if (ret) {
+ clk_put(txx9_imclk);
+ txx9_imclk = NULL;
+ goto exit;
+ }
+
+ res = platform_get_resource(dev, IORESOURCE_MEM, 0);
+ if (!res)
+ goto exit_busy;
+ if (!devm_request_mem_region(&dev->dev,
+ res->start, res->end - res->start + 1,
+ "txx9wdt"))
+ goto exit_busy;
+ txx9wdt_reg = devm_ioremap(&dev->dev,
+ res->start, res->end - res->start + 1);
+ if (!txx9wdt_reg)
+ goto exit_busy;
+
+ ret = register_reboot_notifier(&txx9wdt_notifier);
+ if (ret)
+ goto exit;
+
+ ret = misc_register(&txx9wdt_miscdev);
+ if (ret) {
+ unregister_reboot_notifier(&txx9wdt_notifier);
+ goto exit;
+ }
+
+ printk(KERN_INFO "Hardware Watchdog Timer for TXx9: "
+ "timeout=%d sec (max %ld) (nowayout= %d)\n",
+ timeout, WD_MAX_TIMEOUT, nowayout);
+
+ return 0;
+exit_busy:
+ ret = -EBUSY;
+exit:
+ if (txx9_imclk) {
+ clk_disable(txx9_imclk);
+ clk_put(txx9_imclk);
+ }
+ return ret;
+}
+
+static int __exit txx9wdt_remove(struct platform_device *dev)
+{
+ misc_deregister(&txx9wdt_miscdev);
+ unregister_reboot_notifier(&txx9wdt_notifier);
+ clk_disable(txx9_imclk);
+ clk_put(txx9_imclk);
+ return 0;
+}
+
+static struct platform_driver txx9wdt_driver = {
+ .remove = __exit_p(txx9wdt_remove),
+ .driver = {
+ .name = "txx9wdt",
+ .owner = THIS_MODULE,
+ },
+};
+
+static int __init watchdog_init(void)
+{
+ return platform_driver_probe(&txx9wdt_driver, txx9wdt_probe);
+}
+
+static void __exit watchdog_exit(void)
+{
+ platform_driver_unregister(&txx9wdt_driver);
+}
+
+module_init(watchdog_init);
+module_exit(watchdog_exit);
+
+MODULE_DESCRIPTION("TXx9 Watchdog Driver");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
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