--- /dev/null
+/*
+ * 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);
+
projects / mirror_ubuntu-eoan-kernel.git / commitdiff