[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>

1 files changed, 301 insertions, 0 deletions

diff --git a/drivers/watchdog/pika_wdt.c b/drivers/watchdog/pika_wdt.c
new file mode 100644
index 000000000000..2d22e996e996
--- /dev/null
+++ b/drivers/watchdog/pika_wdt.c
@@ -0,0 +1,301 @@
+/*
+ * 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);
+