// SPDX-License-Identifier: GPL-2.0+ /* * NS pc87413-wdt Watchdog Timer driver for Linux 2.6.x.x * * This code is based on wdt.c with original copyright. * * (C) Copyright 2006 Sven Anders, <anders@anduras.de> * and Marcus Junker, <junker@anduras.de> * * Neither Sven Anders, Marcus Junker nor ANDURAS AG * admit liability nor provide warranty for any of this software. * This material is provided "AS-IS" and at no charge. * * Release 1.1 */ #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt #include <linux/module.h> #include <linux/types.h> #include <linux/miscdevice.h> #include <linux/watchdog.h> #include <linux/ioport.h> #include <linux/delay.h> #include <linux/notifier.h> #include <linux/fs.h> #include <linux/reboot.h> #include <linux/init.h> #include <linux/spinlock.h> #include <linux/moduleparam.h> #include <linux/io.h> #include <linux/uaccess.h> /* #define DEBUG 1 */ #define DEFAULT_TIMEOUT 1 /* 1 minute */ #define MAX_TIMEOUT 255 #define VERSION "1.1" #define MODNAME "pc87413 WDT" #define DPFX MODNAME " - DEBUG: " #define WDT_INDEX_IO_PORT (io+0) /* I/O port base (index register) */ #define WDT_DATA_IO_PORT (WDT_INDEX_IO_PORT+1) #define SWC_LDN 0x04 #define SIOCFG2 0x22 /* Serial IO register */ #define WDCTL 0x10 /* Watchdog-Timer-Control-Register */ #define WDTO 0x11 /* Watchdog timeout register */ #define WDCFG 0x12 /* Watchdog config register */ #define IO_DEFAULT 0x2E /* Address used on Portwell Boards */ static int io = IO_DEFAULT; static int swc_base_addr = -1; static int timeout = DEFAULT_TIMEOUT; /* timeout value */ static unsigned long timer_enabled; /* is the timer enabled? */ static char expect_close; /* is the close expected? */ static DEFINE_SPINLOCK(io_lock); /* to guard us from io races */ static bool nowayout = WATCHDOG_NOWAYOUT; /* -- Low level function ----------------------------------------*/ /* Select pins for Watchdog output */ static inline void pc87413_select_wdt_out(void) { unsigned int cr_data = 0; /* Step 1: Select multiple pin,pin55,as WDT output */ outb_p(SIOCFG2, WDT_INDEX_IO_PORT); cr_data = inb(WDT_DATA_IO_PORT); cr_data |= 0x80; /* Set Bit7 to 1*/ outb_p(SIOCFG2, WDT_INDEX_IO_PORT); outb_p(cr_data, WDT_DATA_IO_PORT); #ifdef DEBUG pr_info(DPFX "Select multiple pin,pin55,as WDT output: Bit7 to 1: %d\n", cr_data); #endif } /* Enable SWC functions */ static inline void pc87413_enable_swc(void) { unsigned int cr_data = 0; /* Step 2: Enable SWC functions */ outb_p(0x07, WDT_INDEX_IO_PORT); /* Point SWC_LDN (LDN=4) */ outb_p(SWC_LDN, WDT_DATA_IO_PORT); outb_p(0x30, WDT_INDEX_IO_PORT); /* Read Index 0x30 First */ cr_data = inb(WDT_DATA_IO_PORT); cr_data |= 0x01; /* Set Bit0 to 1 */ outb_p(0x30, WDT_INDEX_IO_PORT); outb_p(cr_data, WDT_DATA_IO_PORT); /* Index0x30_bit0P1 */ #ifdef DEBUG pr_info(DPFX "pc87413 - Enable SWC functions\n"); #endif } /* Read SWC I/O base address */ static void pc87413_get_swc_base_addr(void) { unsigned char addr_l, addr_h = 0; /* Step 3: Read SWC I/O Base Address */ outb_p(0x60, WDT_INDEX_IO_PORT); /* Read Index 0x60 */ addr_h = inb(WDT_DATA_IO_PORT); outb_p(0x61, WDT_INDEX_IO_PORT); /* Read Index 0x61 */ addr_l = inb(WDT_DATA_IO_PORT); swc_base_addr = (addr_h << 8) + addr_l; #ifdef DEBUG pr_info(DPFX "Read SWC I/O Base Address: low %d, high %d, res %d\n", addr_l, addr_h, swc_base_addr); #endif } /* Select Bank 3 of SWC */ static inline void pc87413_swc_bank3(void) { /* Step 4: Select Bank3 of SWC */ outb_p(inb(swc_base_addr + 0x0f) | 0x03, swc_base_addr + 0x0f); #ifdef DEBUG pr_info(DPFX "Select Bank3 of SWC\n"); #endif } /* Set watchdog timeout to x minutes */ static inline void pc87413_programm_wdto(char pc87413_time) { /* Step 5: Programm WDTO, Twd. */ outb_p(pc87413_time, swc_base_addr + WDTO); #ifdef DEBUG pr_info(DPFX "Set WDTO to %d minutes\n", pc87413_time); #endif } /* Enable WDEN */ static inline void pc87413_enable_wden(void) { /* Step 6: Enable WDEN */ outb_p(inb(swc_base_addr + WDCTL) | 0x01, swc_base_addr + WDCTL); #ifdef DEBUG pr_info(DPFX "Enable WDEN\n"); #endif } /* Enable SW_WD_TREN */ static inline void pc87413_enable_sw_wd_tren(void) { /* Enable SW_WD_TREN */ outb_p(inb(swc_base_addr + WDCFG) | 0x80, swc_base_addr + WDCFG); #ifdef DEBUG pr_info(DPFX "Enable SW_WD_TREN\n"); #endif } /* Disable SW_WD_TREN */ static inline void pc87413_disable_sw_wd_tren(void) { /* Disable SW_WD_TREN */ outb_p(inb(swc_base_addr + WDCFG) & 0x7f, swc_base_addr + WDCFG); #ifdef DEBUG pr_info(DPFX "pc87413 - Disable SW_WD_TREN\n"); #endif } /* Enable SW_WD_TRG */ static inline void pc87413_enable_sw_wd_trg(void) { /* Enable SW_WD_TRG */ outb_p(inb(swc_base_addr + WDCTL) | 0x80, swc_base_addr + WDCTL); #ifdef DEBUG pr_info(DPFX "pc87413 - Enable SW_WD_TRG\n"); #endif } /* Disable SW_WD_TRG */ static inline void pc87413_disable_sw_wd_trg(void) { /* Disable SW_WD_TRG */ outb_p(inb(swc_base_addr + WDCTL) & 0x7f, swc_base_addr + WDCTL); #ifdef DEBUG pr_info(DPFX "Disable SW_WD_TRG\n"); #endif } /* -- Higher level functions ------------------------------------*/ /* Enable the watchdog */ static void pc87413_enable(void) { spin_lock(&io_lock); pc87413_swc_bank3(); pc87413_programm_wdto(timeout); pc87413_enable_wden(); pc87413_enable_sw_wd_tren(); pc87413_enable_sw_wd_trg(); spin_unlock(&io_lock); } /* Disable the watchdog */ static void pc87413_disable(void) { spin_lock(&io_lock); pc87413_swc_bank3(); pc87413_disable_sw_wd_tren(); pc87413_disable_sw_wd_trg(); pc87413_programm_wdto(0); spin_unlock(&io_lock); } /* Refresh the watchdog */ static void pc87413_refresh(void) { spin_lock(&io_lock); pc87413_swc_bank3(); pc87413_disable_sw_wd_tren(); pc87413_disable_sw_wd_trg(); pc87413_programm_wdto(timeout); pc87413_enable_wden(); pc87413_enable_sw_wd_tren(); pc87413_enable_sw_wd_trg(); spin_unlock(&io_lock); } /* -- File operations -------------------------------------------*/ /** * pc87413_open: * @inode: inode of device * @file: file handle to device * */ static int pc87413_open(struct inode *inode, struct file *file) { /* /dev/watchdog can only be opened once */ if (test_and_set_bit(0, &timer_enabled)) return -EBUSY; if (nowayout) __module_get(THIS_MODULE); /* Reload and activate timer */ pc87413_refresh(); pr_info("Watchdog enabled. Timeout set to %d minute(s).\n", timeout); return stream_open(inode, file); } /** * pc87413_release: * @inode: inode to board * @file: file handle to board * * The watchdog has a configurable API. There is a religious dispute * between people who want their watchdog to be able to shut down and * those who want to be sure if the watchdog manager dies the machine * reboots. In the former case we disable the counters, in the latter * case you have to open it again very soon. */ static int pc87413_release(struct inode *inode, struct file *file) { /* Shut off the timer. */ if (expect_close == 42) { pc87413_disable(); pr_info("Watchdog disabled, sleeping again...\n"); } else { pr_crit("Unexpected close, not stopping watchdog!\n"); pc87413_refresh(); } clear_bit(0, &timer_enabled); expect_close = 0; return 0; } /** * pc87413_status: * * return, if the watchdog is enabled (timeout is set...) */ static int pc87413_status(void) { return 0; /* currently not supported */ } /** * pc87413_write: * @file: file handle to the watchdog * @data: data buffer to write * @len: length in bytes * @ppos: pointer to the position to write. No seeks allowed * * A write to a watchdog device is defined as a keepalive signal. Any * write of data will do, as we we don't define content meaning. */ static ssize_t pc87413_write(struct file *file, const char __user *data, size_t len, loff_t *ppos) { /* See if we got the magic character 'V' and reload the timer */ if (len) { if (!nowayout) { size_t i; /* reset expect flag */ expect_close = 0; /* scan to see whether or not we got the magic character */ for (i = 0; i != len; i++) { char c; if (get_user(c, data + i)) return -EFAULT; if (c == 'V') expect_close = 42; } } /* someone wrote to us, we should reload the timer */ pc87413_refresh(); } return len; } /** * pc87413_ioctl: * @file: file handle to the device * @cmd: watchdog command * @arg: argument pointer * * The watchdog API defines a common set of functions for all watchdogs * according to their available features. We only actually usefully support * querying capabilities and current status. */ static long pc87413_ioctl(struct file *file, unsigned int cmd, unsigned long arg) { int new_timeout; union { struct watchdog_info __user *ident; int __user *i; } uarg; static const struct watchdog_info ident = { .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE, .firmware_version = 1, .identity = "PC87413(HF/F) watchdog", }; uarg.i = (int __user *)arg; switch (cmd) { case WDIOC_GETSUPPORT: return copy_to_user(uarg.ident, &ident, sizeof(ident)) ? -EFAULT : 0; case WDIOC_GETSTATUS: return put_user(pc87413_status(), uarg.i); case WDIOC_GETBOOTSTATUS: return put_user(0, uarg.i); case WDIOC_SETOPTIONS: { int options, retval = -EINVAL; if (get_user(options, uarg.i)) return -EFAULT; if (options & WDIOS_DISABLECARD) { pc87413_disable(); retval = 0; } if (options & WDIOS_ENABLECARD) { pc87413_enable(); retval = 0; } return retval; } case WDIOC_KEEPALIVE: pc87413_refresh(); #ifdef DEBUG pr_info(DPFX "keepalive\n"); #endif return 0; case WDIOC_SETTIMEOUT: if (get_user(new_timeout, uarg.i)) return -EFAULT; /* the API states this is given in secs */ new_timeout /= 60; if (new_timeout < 0 || new_timeout > MAX_TIMEOUT) return -EINVAL; timeout = new_timeout; pc87413_refresh(); fallthrough; /* and return the new timeout */ case WDIOC_GETTIMEOUT: new_timeout = timeout * 60; return put_user(new_timeout, uarg.i); default: return -ENOTTY; } } /* -- Notifier functions -----------------------------------------*/ /** * pc87413_notify_sys: * @this: our notifier block * @code: the event being reported * @unused: unused * * Our notifier is called on system shutdowns. We want to turn the card * off at reboot otherwise the machine will reboot again during memory * test or worse yet during the following fsck. This would suck, in fact * trust me - if it happens it does suck. */ static int pc87413_notify_sys(struct notifier_block *this, unsigned long code, void *unused) { if (code == SYS_DOWN || code == SYS_HALT) /* Turn the card off */ pc87413_disable(); return NOTIFY_DONE; } /* -- Module's structures ---------------------------------------*/ static const struct file_operations pc87413_fops = { .owner = THIS_MODULE, .llseek = no_llseek, .write = pc87413_write, .unlocked_ioctl = pc87413_ioctl, .compat_ioctl = compat_ptr_ioctl, .open = pc87413_open, .release = pc87413_release, }; static struct notifier_block pc87413_notifier = { .notifier_call = pc87413_notify_sys, }; static struct miscdevice pc87413_miscdev = { .minor = WATCHDOG_MINOR, .name = "watchdog", .fops = &pc87413_fops, }; /* -- Module init functions -------------------------------------*/ /** * pc87413_init: module's "constructor" * * Set up the WDT watchdog board. All we have to do is grab the * resources we require and bitch if anyone beat us to them. * The open() function will actually kick the board off. */ static int __init pc87413_init(void) { int ret; pr_info("Version " VERSION " at io 0x%X\n", WDT_INDEX_IO_PORT); if (!request_muxed_region(io, 2, MODNAME)) return -EBUSY; ret = register_reboot_notifier(&pc87413_notifier); if (ret != 0) pr_err("cannot register reboot notifier (err=%d)\n", ret); ret = misc_register(&pc87413_miscdev); if (ret != 0) { pr_err("cannot register miscdev on minor=%d (err=%d)\n", WATCHDOG_MINOR, ret); goto reboot_unreg; } pr_info("initialized. timeout=%d min\n", timeout); pc87413_select_wdt_out(); pc87413_enable_swc(); pc87413_get_swc_base_addr(); if (!request_region(swc_base_addr, 0x20, MODNAME)) { pr_err("cannot request SWC region at 0x%x\n", swc_base_addr); ret = -EBUSY; goto misc_unreg; } pc87413_enable(); release_region(io, 2); return 0; misc_unreg: misc_deregister(&pc87413_miscdev); reboot_unreg: unregister_reboot_notifier(&pc87413_notifier); release_region(io, 2); return ret; } /** * pc87413_exit: module's "destructor" * * Unload the watchdog. You cannot do this with any file handles open. * If your watchdog is set to continue ticking on close and you unload * it, well it keeps ticking. We won't get the interrupt but the board * will not touch PC memory so all is fine. You just have to load a new * module in 60 seconds or reboot. */ static void __exit pc87413_exit(void) { /* Stop the timer before we leave */ if (!nowayout) { pc87413_disable(); pr_info("Watchdog disabled\n"); } misc_deregister(&pc87413_miscdev); unregister_reboot_notifier(&pc87413_notifier); release_region(swc_base_addr, 0x20); pr_info("watchdog component driver removed\n"); } module_init(pc87413_init); module_exit(pc87413_exit); MODULE_AUTHOR("Sven Anders <anders@anduras.de>"); MODULE_AUTHOR("Marcus Junker <junker@anduras.de>"); MODULE_DESCRIPTION("PC87413 WDT driver"); MODULE_LICENSE("GPL"); module_param_hw(io, int, ioport, 0); MODULE_PARM_DESC(io, MODNAME " I/O port (default: " __MODULE_STRING(IO_DEFAULT) ")."); module_param(timeout, int, 0); MODULE_PARM_DESC(timeout, "Watchdog timeout in minutes (default=" __MODULE_STRING(DEFAULT_TIMEOUT) ")."); module_param(nowayout, bool, 0); MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");