/* * PIKA FPGA based Watchdog Timer * * Copyright (c) 2008 PIKA Technologies * Sean MacLennan <smaclennan@pikatech.com> */ #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt #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_address.h> #include <linux/of_platform.h> #define DRV_NAME "PIKA-WDT" /* 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 bool nowayout = WATCHDOG_NOWAYOUT; module_param(nowayout, bool, 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 __ro_after_init = { .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(struct timer_list *unused) { if (time_before(jiffies, pikawdt_private.next_heartbeat) || (!nowayout && !pikawdt_private.open)) { pikawdt_reset(); mod_timer(&pikawdt_private.timer, jiffies + WDT_TIMEOUT); } else pr_crit("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) { pr_err("Unable to find fpga\n"); return -ENOENT; } pikawdt_private.fpga = of_iomap(np, 0); of_node_put(np); if (pikawdt_private.fpga == NULL) { pr_err("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) { pr_err("Unable to find fpga-sd\n"); ret = -ENOENT; goto out; } fpga = of_iomap(np, 0); of_node_put(np); if (fpga == NULL) { pr_err("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); timer_setup(&pikawdt_private.timer, pikawdt_ping, 0); ret = misc_register(&pikawdt_miscdev); if (ret) { pr_err("Unable to register miscdev\n"); goto out; } pr_info("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");