[WATCHDOG] Pika Warp appliance watchdog timer

The FPGA based watchdog timer used by the Pika Warp appliance.
Signed-off-by: Sean MacLennan <smaclennan@pikatech.com>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>

drivers/watchdog/Kconfig

@@ -796,6 +796,14 @@ config MV64X60_WDT
 	tristate "MV64X60 (Marvell Discovery) Watchdog Timer"
 	depends on MV64X60
 
+config PIKA_WDT
+	tristate "PIKA FPGA Watchdog"
+	depends on WARP
+	default y
+	help
+	  This enables the watchdog in the PIKA FPGA. Currently used on
+	  the Warp platform.
+
 config BOOKE_WDT
 	bool "PowerPC Book-E Watchdog Timer"
 	depends on BOOKE || 4xx

drivers/watchdog/Makefile

@@ -115,6 +115,7 @@ obj-$(CONFIG_GEF_WDT) += gef_wdt.o
 obj-$(CONFIG_MPC5200_WDT) += mpc5200_wdt.o
 obj-$(CONFIG_8xxx_WDT) += mpc8xxx_wdt.o
 obj-$(CONFIG_MV64X60_WDT) += mv64x60_wdt.o
+obj-$(CONFIG_PIKA_WDT) += pika_wdt.o
 obj-$(CONFIG_BOOKE_WDT) += booke_wdt.o
 
 # PPC64 Architecture

drivers/watchdog/pika_wdt.c

+/*
+ * PIKA FPGA based Watchdog Timer
+ *
+ * Copyright (c) 2008 PIKA Technologies
+ *   Sean MacLennan <smaclennan@pikatech.com>
+ */
+
+#include <linux/init.h>
+#include <linux/errno.h>
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/types.h>
+#include <linux/kernel.h>
+#include <linux/fs.h>
+#include <linux/miscdevice.h>
+#include <linux/watchdog.h>
+#include <linux/reboot.h>
+#include <linux/jiffies.h>
+#include <linux/timer.h>
+#include <linux/bitops.h>
+#include <linux/uaccess.h>
+#include <linux/io.h>
+#include <linux/of_platform.h>
+
+#define DRV_NAME "PIKA-WDT"
+#define PFX DRV_NAME ": "
+
+/* Hardware timeout in seconds */
+#define WDT_HW_TIMEOUT 2
+
+/* Timer heartbeat (500ms) */
+#define WDT_TIMEOUT	(HZ/2)
+
+/* User land timeout */
+#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 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 struct {
+	void __iomem *fpga;
+	unsigned long next_heartbeat;	/* the next_heartbeat for the timer */
+	unsigned long open;
+	char expect_close;
+	int bootstatus;
+	struct timer_list timer;	/* The timer that pings the watchdog */
+} pikawdt_private;
+
+static struct watchdog_info ident = {
+	.identity	= DRV_NAME,
+	.options	= WDIOF_CARDRESET |
+			  WDIOF_SETTIMEOUT |
+			  WDIOF_KEEPALIVEPING |
+			  WDIOF_MAGICCLOSE,
+};
+
+/*
+ * Reload the watchdog timer.  (ie, pat the watchdog)
+ */
+static inline void pikawdt_reset(void)
+{
+	/* -- FPGA: Reset Control Register (32bit R/W) (Offset: 0x14) --
+	 * Bit 7,    WTCHDG_EN: When set to 1, the watchdog timer is enabled.
+	 *           Once enabled, it cannot be disabled. The watchdog can be
+	 *           kicked by performing any write access to the reset
+	 *           control register (this register).
+	 * Bit 8-11, WTCHDG_TIMEOUT_SEC: Sets the watchdog timeout value in
+	 *           seconds. Valid ranges are 1 to 15 seconds. The value can
+	 *           be modified dynamically.
+	 */
+	unsigned reset = in_be32(pikawdt_private.fpga + 0x14);
+	/* enable with max timeout - 15 seconds */
+	reset |= (1 << 7) + (WDT_HW_TIMEOUT << 8);
+	out_be32(pikawdt_private.fpga + 0x14, reset);
+}
+
+/*
+ * Timer tick
+ */
+static void pikawdt_ping(unsigned long data)
+{
+	if (time_before(jiffies, pikawdt_private.next_heartbeat) ||
+			(!nowayout && !pikawdt_private.open)) {
+		pikawdt_reset();
+		mod_timer(&pikawdt_private.timer, jiffies + WDT_TIMEOUT);
+	} else
+		printk(KERN_CRIT PFX "I will reset your machine !\n");
+}
+
+
+static void pikawdt_keepalive(void)
+{
+	pikawdt_private.next_heartbeat = jiffies + heartbeat * HZ;
+}
+
+static void pikawdt_start(void)
+{
+	pikawdt_keepalive();
+	mod_timer(&pikawdt_private.timer, jiffies + WDT_TIMEOUT);
+}
+
+/*
+ * Watchdog device is opened, and watchdog starts running.
+ */
+static int pikawdt_open(struct inode *inode, struct file *file)
+{
+	/* /dev/watchdog can only be opened once */
+	if (test_and_set_bit(0, &pikawdt_private.open))
+		return -EBUSY;
+
+	pikawdt_start();
+
+	return nonseekable_open(inode, file);
+}
+
+/*
+ * Close the watchdog device.
+ */
+static int pikawdt_release(struct inode *inode, struct file *file)
+{
+	/* stop internal ping */
+	if (!pikawdt_private.expect_close)
+		del_timer(&pikawdt_private.timer);
+
+	clear_bit(0, &pikawdt_private.open);
+	pikawdt_private.expect_close = 0;
+	return 0;
+}
+
+/*
+ * Pat the watchdog whenever device is written to.
+ */
+static ssize_t pikawdt_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;
+
+		pikawdt_private.expect_close = 0;
+
+		for (i = 0; i < len; i++) {
+			char c;
+			if (get_user(c, data + i))
+				return -EFAULT;
+			if (c == 'V') {
+				pikawdt_private.expect_close = 42;
+				break;
+			}
+		}
+	}
+
+	pikawdt_keepalive();
+
+	return len;
+}
+
+/*
+ * Handle commands from user-space.
+ */
+static long pikawdt_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, &ident, sizeof(ident)) ? -EFAULT : 0;
+
+	case WDIOC_GETSTATUS:
+		return put_user(0, p);
+
+	case WDIOC_GETBOOTSTATUS:
+		return put_user(pikawdt_private.bootstatus, p);
+
+	case WDIOC_KEEPALIVE:
+		pikawdt_keepalive();
+		return 0;
+
+	case WDIOC_SETTIMEOUT:
+		if (get_user(new_value, p))
+			return -EFAULT;
+
+		heartbeat = new_value;
+		pikawdt_keepalive();
+
+		return put_user(new_value, p);  /* return current value */
+
+	case WDIOC_GETTIMEOUT:
+		return put_user(heartbeat, p);
+	}
+	return -ENOTTY;
+}
+
+
+static const struct file_operations pikawdt_fops = {
+	.owner		= THIS_MODULE,
+	.llseek		= no_llseek,
+	.open		= pikawdt_open,
+	.release	= pikawdt_release,
+	.write		= pikawdt_write,
+	.unlocked_ioctl	= pikawdt_ioctl,
+};
+
+static struct miscdevice pikawdt_miscdev = {
+	.minor	= WATCHDOG_MINOR,
+	.name	= "watchdog",
+	.fops	= &pikawdt_fops,
+};
+
+static int __init pikawdt_init(void)
+{
+	struct device_node *np;
+	void __iomem *fpga;
+	static u32 post1;
+	int ret;
+
+	np = of_find_compatible_node(NULL, NULL, "pika,fpga");
+	if (np == NULL) {
+		printk(KERN_ERR PFX "Unable to find fpga.\n");
+		return -ENOENT;
+	}
+
+	pikawdt_private.fpga = of_iomap(np, 0);
+	of_node_put(np);
+	if (pikawdt_private.fpga == NULL) {
+		printk(KERN_ERR PFX "Unable to map fpga.\n");
+		return -ENOMEM;
+	}
+
+	ident.firmware_version = in_be32(pikawdt_private.fpga + 0x1c) & 0xffff;
+
+	/* POST information is in the sd area. */
+	np = of_find_compatible_node(NULL, NULL, "pika,fpga-sd");
+	if (np == NULL) {
+		printk(KERN_ERR PFX "Unable to find fpga-sd.\n");
+		ret = -ENOENT;
+		goto out;
+	}
+
+	fpga = of_iomap(np, 0);
+	of_node_put(np);
+	if (fpga == NULL) {
+		printk(KERN_ERR PFX "Unable to map fpga-sd.\n");
+		ret = -ENOMEM;
+		goto out;
+	}
+
+	/* -- FPGA: POST Test Results Register 1 (32bit R/W) (Offset: 0x4040) --
+	 * Bit 31,   WDOG: Set to 1 when the last reset was caused by a watchdog
+	 *           timeout.
+	 */
+	post1 = in_be32(fpga + 0x40);
+	if (post1 & 0x80000000)
+		pikawdt_private.bootstatus = WDIOF_CARDRESET;
+
+	iounmap(fpga);
+
+	setup_timer(&pikawdt_private.timer, pikawdt_ping, 0);
+
+	ret = misc_register(&pikawdt_miscdev);
+	if (ret) {
+		printk(KERN_ERR PFX "Unable to register miscdev.\n");
+		goto out;
+	}
+
+	printk(KERN_INFO PFX "initialized. heartbeat=%d sec (nowayout=%d)\n",
+							heartbeat, nowayout);
+	return 0;
+
+out:
+	iounmap(pikawdt_private.fpga);
+	return ret;
+}
+
+static void __exit pikawdt_exit(void)
+{
+	misc_deregister(&pikawdt_miscdev);
+
+	iounmap(pikawdt_private.fpga);
+}
+
+module_init(pikawdt_init);
+module_exit(pikawdt_exit);
+
+MODULE_AUTHOR("Sean MacLennan <smaclennan@pikatech.com>");
+MODULE_DESCRIPTION("PIKA FPGA based Watchdog Timer");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
+