[WATCHDOG] MIPS RM9000 on-chip watchdog device

This is a driver for the on-chip watchdog device found on some
MIPS RM9000 processors.
Signed-off-by: NThomas Koeller <thomas.koeller@baslerweb.com>
Signed-off-by: NWim Van Sebroeck <wim@iguana.be>

drivers/char/watchdog/Kconfig

@@ -575,6 +575,16 @@ config INDYDOG
 	  timer expired and no process has written to /dev/watchdog during
 	  that time.
 
+config WDT_RM9K_GPI
+	tristate "RM9000/GPI hardware watchdog"
+	depends on WATCHDOG && CPU_RM9000
+	help
+	  Watchdog implementation using the GPI hardware found on
+	  PMC-Sierra RM9xxx CPUs.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called rm9k_wdt.
+
 # S390 Architecture
 
 config ZVM_WATCHDOG

drivers/char/watchdog/Makefile

@@ -73,6 +73,7 @@ obj-$(CONFIG_WATCHDOG_RTAS) += wdrtas.o
 
 # MIPS Architecture
 obj-$(CONFIG_INDYDOG) += indydog.o
+obj-$(CONFIG_WDT_RM9K_GPI) += rm9k_wdt.o
 
 # S390 Architecture
 

drivers/char/watchdog/rm9k_wdt.c

+/*
+ *  Watchdog implementation for GPI h/w found on PMC-Sierra RM9xxx
+ *  chips.
+ *
+ *  Copyright (C) 2004 by Basler Vision Technologies AG
+ *  Author: Thomas Koeller <thomas.koeller@baslerweb.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; either version 2 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program; if not, write to the Free Software
+ *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#include <linux/platform_device.h>
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/interrupt.h>
+#include <linux/fs.h>
+#include <linux/reboot.h>
+#include <linux/miscdevice.h>
+#include <linux/watchdog.h>
+#include <asm/io.h>
+#include <asm/atomic.h>
+#include <asm/processor.h>
+#include <asm/uaccess.h>
+#include <asm/system.h>
+#include <asm/rm9k-ocd.h>
+
+#include <rm9k_wdt.h>
+
+
+#define CLOCK                  125000000
+#define MAX_TIMEOUT_SECONDS    32
+#define CPCCR                  0x0080
+#define CPGIG1SR               0x0044
+#define CPGIG1ER               0x0054
+
+
+
+/* Function prototypes */
+static int __init wdt_gpi_probe(struct device *);
+static int __exit wdt_gpi_remove(struct device *);
+static void wdt_gpi_set_timeout(unsigned int);
+static int wdt_gpi_open(struct inode *, struct file *);
+static int wdt_gpi_release(struct inode *, struct file *);
+static ssize_t wdt_gpi_write(struct file *, const char __user *, size_t, loff_t *);
+static long wdt_gpi_ioctl(struct file *, unsigned int, unsigned long);
+static const struct resource *wdt_gpi_get_resource(struct platform_device *, const char *, unsigned int);
+static int wdt_gpi_notify(struct notifier_block *, unsigned long, void *);
+static irqreturn_t wdt_gpi_irqhdl(int, void *, struct pt_regs *);
+
+
+
+
+static const char wdt_gpi_name[] = "wdt_gpi";
+static atomic_t opencnt;
+static int expect_close;
+static int locked = 0;
+
+
+
+/* These are set from device resources */
+static void __iomem * wd_regs;
+static unsigned int wd_irq, wd_ctr;
+
+
+
+/* Module arguments */
+static int timeout = MAX_TIMEOUT_SECONDS;
+module_param(timeout, int, 0444);
+static unsigned long resetaddr = 0xbffdc200;
+module_param(resetaddr, ulong, 0444);
+static unsigned long flagaddr = 0xbffdc104;
+module_param(flagaddr, ulong, 0444);
+static int powercycle = 0;
+module_param(powercycle, bool, 0444);
+
+static int nowayout = WATCHDOG_NOWAYOUT;
+module_param(nowayout, bool, 0444);
+
+
+
+static struct file_operations fops = {
+	.owner		= THIS_MODULE,
+	.open		= wdt_gpi_open,
+	.release	= wdt_gpi_release,
+	.write		= wdt_gpi_write,
+	.unlocked_ioctl	= wdt_gpi_ioctl,
+};
+
+static struct miscdevice miscdev = {
+	.minor		= WATCHDOG_MINOR,
+	.name		= wdt_gpi_name,
+	.fops		= &fops,
+};
+
+static struct device_driver wdt_gpi_driver = {
+	.name		= (char *) wdt_gpi_name,
+	.bus		= &platform_bus_type,
+	.owner		= THIS_MODULE,
+	.probe		= wdt_gpi_probe,
+	.remove		= __exit_p(wdt_gpi_remove),
+	.shutdown	= NULL,
+	.suspend	= NULL,
+	.resume		= NULL,
+};
+
+static struct notifier_block wdt_gpi_shutdown = {
+	.notifier_call	= wdt_gpi_notify,
+};
+
+
+
+static const struct resource *
+wdt_gpi_get_resource(struct platform_device *pdv, const char *name,
+		      unsigned int type)
+{
+	char buf[80];
+	if (snprintf(buf, sizeof buf, "%s_0", name) >= sizeof buf)
+		return NULL;
+	return platform_get_resource_byname(pdv, type, buf);
+}
+
+
+
+/* No hotplugging on the platform bus - use __init */
+static int __init wdt_gpi_probe(struct device *dev)
+{
+	int res;
+	struct platform_device * const pdv = to_platform_device(dev);
+	const struct resource
+		* const rr = wdt_gpi_get_resource(pdv, WDT_RESOURCE_REGS,
+						  IORESOURCE_MEM),
+		* const ri = wdt_gpi_get_resource(pdv, WDT_RESOURCE_IRQ,
+						  IORESOURCE_IRQ),
+		* const rc = wdt_gpi_get_resource(pdv, WDT_RESOURCE_COUNTER,
+						  0);
+
+	if (unlikely(!rr || !ri || !rc))
+		return -ENXIO;
+
+	wd_regs = ioremap_nocache(rr->start, rr->end + 1 - rr->start);
+	if (unlikely(!wd_regs))
+		return -ENOMEM;
+	wd_irq = ri->start;
+	wd_ctr = rc->start;
+	res = misc_register(&miscdev);
+	if (res)
+		iounmap(wd_regs);
+	else
+		register_reboot_notifier(&wdt_gpi_shutdown);
+	return res;
+}
+
+
+
+static int __exit wdt_gpi_remove(struct device *dev)
+{
+	int res;
+
+	unregister_reboot_notifier(&wdt_gpi_shutdown);
+	res = misc_deregister(&miscdev);
+	iounmap(wd_regs);
+	wd_regs = NULL;
+	return res;
+}
+
+
+static void wdt_gpi_set_timeout(unsigned int to)
+{
+	u32 reg;
+	const u32 wdval = (to * CLOCK) & ~0x0000000f;
+
+	lock_titan_regs();
+	reg = titan_readl(CPCCR) & ~(0xf << (wd_ctr * 4));
+	titan_writel(reg, CPCCR);
+	wmb();
+	__raw_writel(wdval, wd_regs + 0x0000);
+	wmb();
+	titan_writel(reg | (0x2 << (wd_ctr * 4)), CPCCR);
+	wmb();
+	titan_writel(reg | (0x5 << (wd_ctr * 4)), CPCCR);
+	iob();
+	unlock_titan_regs();
+}
+
+
+
+static int wdt_gpi_open(struct inode *i, struct file *f)
+{
+	int res;
+	u32 reg;
+
+	if (unlikely(0 > atomic_dec_if_positive(&opencnt)))
+		return -EBUSY;
+
+	expect_close = 0;
+	if (locked) {
+		module_put(THIS_MODULE);
+		free_irq(wd_irq, &miscdev);
+		locked = 0;
+	}
+
+	res = request_irq(wd_irq, wdt_gpi_irqhdl, SA_SHIRQ | SA_INTERRUPT,
+			  wdt_gpi_name, &miscdev);
+	if (unlikely(res))
+		return res;
+
+	wdt_gpi_set_timeout(timeout);
+
+	lock_titan_regs();
+	reg = titan_readl(CPGIG1ER);
+	titan_writel(reg | (0x100 << wd_ctr), CPGIG1ER);
+	iob();
+	unlock_titan_regs();
+
+	printk(KERN_INFO "%s: watchdog started, timeout = %u seconds\n",
+		wdt_gpi_name, timeout);
+	return 0;
+}
+
+
+
+static int wdt_gpi_release(struct inode *i, struct file *f)
+{
+	if (nowayout) {
+		printk(KERN_NOTICE "%s: no way out - watchdog left running\n",
+			wdt_gpi_name);
+		__module_get(THIS_MODULE);
+		locked = 1;
+	} else {
+		if (expect_close) {
+			u32 reg;
+
+			lock_titan_regs();
+			reg = titan_readl(CPCCR) & ~(0xf << (wd_ctr * 4));
+			titan_writel(reg, CPCCR);
+			reg = titan_readl(CPGIG1ER);
+			titan_writel(reg & ~(0x100 << wd_ctr), CPGIG1ER);
+			iob();
+			unlock_titan_regs();
+			free_irq(wd_irq, &miscdev);
+			printk(KERN_INFO "%s: watchdog stopped\n", wdt_gpi_name);
+		} else {
+			printk(KERN_NOTICE "%s: unexpected close() -"
+				" watchdog left running\n",
+				wdt_gpi_name);
+			wdt_gpi_set_timeout(timeout);
+			__module_get(THIS_MODULE);
+			locked = 1;
+		}
+	}
+
+	atomic_inc(&opencnt);
+	return 0;
+}
+
+
+
+static ssize_t
+wdt_gpi_write(struct file *f, const char __user *d, size_t s, loff_t *o)
+{
+	char val;
+
+	wdt_gpi_set_timeout(timeout);
+	expect_close = (s > 0) && !get_user(val, d) && (val == 'V');
+	return s ? 1 : 0;
+}
+
+
+
+static long
+wdt_gpi_ioctl(struct file *f, unsigned int cmd, unsigned long arg)
+{
+	long res = -ENOTTY;
+	const long size = _IOC_SIZE(cmd);
+	int stat;
+	static struct watchdog_info wdinfo = {
+		.identity               = "RM9xxx/GPI watchdog",
+		.firmware_version       = 0,
+		.options                = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING
+	};
+
+	if (unlikely(_IOC_TYPE(cmd) != WATCHDOG_IOCTL_BASE))
+		return -ENOTTY;
+
+	if ((_IOC_DIR(cmd) & _IOC_READ)
+	    && !access_ok(VERIFY_WRITE, arg, size))
+		return -EFAULT;
+
+	if ((_IOC_DIR(cmd) & _IOC_WRITE)
+	    && !access_ok(VERIFY_READ, arg, size))
+		return -EFAULT;
+
+	expect_close = 0;
+
+	switch (cmd) {
+	case WDIOC_GETSUPPORT:
+		wdinfo.options = nowayout ?
+			WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING :
+			WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE;
+		res = __copy_to_user((void __user *)arg, &wdinfo, size) ?
+			-EFAULT : size;
+		break;
+
+	case WDIOC_GETSTATUS:
+		break;
+
+	case WDIOC_GETBOOTSTATUS:
+		stat = (*(volatile char *) flagaddr & 0x01)
+			? WDIOF_CARDRESET : 0;
+		res = __copy_to_user((void __user *)arg, &stat, size) ?
+			-EFAULT : size;
+		break;
+
+	case WDIOC_SETOPTIONS:
+		break;
+
+	case WDIOC_KEEPALIVE:
+		wdt_gpi_set_timeout(timeout);
+		res = size;
+		break;
+
+	case WDIOC_SETTIMEOUT:
+		{
+			int val;
+			if (unlikely(__copy_from_user(&val, (const void __user *) arg,
+					size))) {
+				res = -EFAULT;
+				break;
+			}
+
+			if (val > 32)
+				val = 32;
+			timeout = val;
+			wdt_gpi_set_timeout(val);
+			res = size;
+			printk("%s: timeout set to %u seconds\n",
+				wdt_gpi_name, timeout);
+		}
+		break;
+
+	case WDIOC_GETTIMEOUT:
+		res = __copy_to_user((void __user *) arg, &timeout, size) ?
+			-EFAULT : size;
+		break;
+	}
+
+	return res;
+}
+
+
+
+
+static irqreturn_t wdt_gpi_irqhdl(int irq, void *ctxt, struct pt_regs *regs)
+{
+	if (!unlikely(__raw_readl(wd_regs + 0x0008) & 0x1))
+		return IRQ_NONE;
+	__raw_writel(0x1, wd_regs + 0x0008);
+
+
+	printk(KERN_WARNING "%s: watchdog expired - resetting system\n",
+		wdt_gpi_name);
+
+	*(volatile char *) flagaddr |= 0x01;
+	*(volatile char *) resetaddr = powercycle ? 0x01 : 0x2;
+	iob();
+	while (1)
+		cpu_relax();
+}
+
+
+
+static int
+wdt_gpi_notify(struct notifier_block *this, unsigned long code, void *unused)
+{
+	if(code == SYS_DOWN || code == SYS_HALT) {
+		u32 reg;
+
+		lock_titan_regs();
+		reg = titan_readl(CPCCR) & ~(0xf << (wd_ctr * 4));
+		titan_writel(reg, CPCCR);
+		reg = titan_readl(CPGIG1ER);
+		titan_writel(reg & ~(0x100 << wd_ctr), CPGIG1ER);
+		iob();
+		unlock_titan_regs();
+	}
+	return NOTIFY_DONE;
+}
+
+
+
+static int __init wdt_gpi_init_module(void)
+{
+	atomic_set(&opencnt, 1);
+	if (timeout > MAX_TIMEOUT_SECONDS)
+		timeout = MAX_TIMEOUT_SECONDS;
+	return driver_register(&wdt_gpi_driver);
+}
+
+
+
+static void __exit wdt_gpi_cleanup_module(void)
+{
+	driver_unregister(&wdt_gpi_driver);
+}
+
+module_init(wdt_gpi_init_module);
+module_exit(wdt_gpi_cleanup_module);
+
+
+
+MODULE_AUTHOR("Thomas Koeller <thomas.koeller@baslerweb.com>");
+MODULE_DESCRIPTION("Basler eXcite watchdog driver for gpi devices");
+MODULE_VERSION("0.1");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
+MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds");
+MODULE_PARM_DESC(resetaddr, "Address to write to to force a reset");
+MODULE_PARM_DESC(flagaddr, "Address to write to boot flags to");
+MODULE_PARM_DESC(nowayout, "Watchdog cannot be disabled once started");
+MODULE_PARM_DESC(powercycle, "Cycle power if watchdog expires");