ramips: add watchdog driver

git-svn-id: svn://svn.openwrt.org/openwrt/trunk@25126 3c298f89-4303-0410-b956-a3cf2f4a3e73

1 files changed, 355 insertions, 0 deletions

diff --git a/target/linux/ramips/files/drivers/watchdog/ramips_wdt.c b/target/linux/ramips/files/drivers/watchdog/ramips_wdt.c
new file mode 100644
index 000000000..a0b56c8cb
--- /dev/null
+++ b/target/linux/ramips/files/drivers/watchdog/ramips_wdt.c
@@ -0,0 +1,355 @@
+/*
+ * 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);