// SPDX-License-Identifier: GPL-2.0-or-later /* * nv_tco 0.01: TCO timer driver for NV chipsets * * (c) Copyright 2005 Google Inc., All Rights Reserved. * * Based off i8xx_tco.c: * (c) Copyright 2000 kernel concepts <nils@kernelconcepts.de>, All Rights * Reserved. * http://www.kernelconcepts.de * * TCO timer driver for NV chipsets * based on softdog.c by Alan Cox <alan@redhat.com> */ /* * Includes, defines, variables, module parameters, ... */ #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt #include <linux/module.h> #include <linux/moduleparam.h> #include <linux/types.h> #include <linux/miscdevice.h> #include <linux/watchdog.h> #include <linux/init.h> #include <linux/fs.h> #include <linux/pci.h> #include <linux/ioport.h> #include <linux/jiffies.h> #include <linux/platform_device.h> #include <linux/uaccess.h> #include <linux/io.h> #include "nv_tco.h" /* Module and version information */ #define TCO_VERSION "0.01" #define TCO_MODULE_NAME "NV_TCO" #define TCO_DRIVER_NAME TCO_MODULE_NAME ", v" TCO_VERSION /* internal variables */ static unsigned int tcobase; static DEFINE_SPINLOCK(tco_lock); /* Guards the hardware */ static unsigned long timer_alive; static char tco_expect_close; static struct pci_dev *tco_pci; /* the watchdog platform device */ static struct platform_device *nv_tco_platform_device; /* module parameters */ #define WATCHDOG_HEARTBEAT 30 /* 30 sec default heartbeat (2<heartbeat<39) */ static int heartbeat = WATCHDOG_HEARTBEAT; /* in seconds */ module_param(heartbeat, int, 0); MODULE_PARM_DESC(heartbeat, "Watchdog heartbeat in seconds. (2<heartbeat<39, " "default=" __MODULE_STRING(WATCHDOG_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) ")"); /* * Some TCO specific functions */ static inline unsigned char seconds_to_ticks(int seconds) { /* the internal timer is stored as ticks which decrement * every 0.6 seconds */ return (seconds * 10) / 6; } static void tco_timer_start(void) { u32 val; unsigned long flags; spin_lock_irqsave(&tco_lock, flags); val = inl(TCO_CNT(tcobase)); val &= ~TCO_CNT_TCOHALT; outl(val, TCO_CNT(tcobase)); spin_unlock_irqrestore(&tco_lock, flags); } static void tco_timer_stop(void) { u32 val; unsigned long flags; spin_lock_irqsave(&tco_lock, flags); val = inl(TCO_CNT(tcobase)); val |= TCO_CNT_TCOHALT; outl(val, TCO_CNT(tcobase)); spin_unlock_irqrestore(&tco_lock, flags); } static void tco_timer_keepalive(void) { unsigned long flags; spin_lock_irqsave(&tco_lock, flags); outb(0x01, TCO_RLD(tcobase)); spin_unlock_irqrestore(&tco_lock, flags); } static int tco_timer_set_heartbeat(int t) { int ret = 0; unsigned char tmrval; unsigned long flags; u8 val; /* * note seconds_to_ticks(t) > t, so if t > 0x3f, so is * tmrval=seconds_to_ticks(t). Check that the count in seconds isn't * out of range on it's own (to avoid overflow in tmrval). */ if (t < 0 || t > 0x3f) return -EINVAL; tmrval = seconds_to_ticks(t); /* "Values of 0h-3h are ignored and should not be attempted" */ if (tmrval > 0x3f || tmrval < 0x04) return -EINVAL; /* Write new heartbeat to watchdog */ spin_lock_irqsave(&tco_lock, flags); val = inb(TCO_TMR(tcobase)); val &= 0xc0; val |= tmrval; outb(val, TCO_TMR(tcobase)); val = inb(TCO_TMR(tcobase)); if ((val & 0x3f) != tmrval) ret = -EINVAL; spin_unlock_irqrestore(&tco_lock, flags); if (ret) return ret; heartbeat = t; return 0; } /* * /dev/watchdog handling */ static int nv_tco_open(struct inode *inode, struct file *file) { /* /dev/watchdog can only be opened once */ if (test_and_set_bit(0, &timer_alive)) return -EBUSY; /* Reload and activate timer */ tco_timer_keepalive(); tco_timer_start(); return stream_open(inode, file); } static int nv_tco_release(struct inode *inode, struct file *file) { /* Shut off the timer */ if (tco_expect_close == 42) { tco_timer_stop(); } else { pr_crit("Unexpected close, not stopping watchdog!\n"); tco_timer_keepalive(); } clear_bit(0, &timer_alive); tco_expect_close = 0; return 0; } static ssize_t nv_tco_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; /* * note: just in case someone wrote the magic character * five months ago... */ tco_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') tco_expect_close = 42; } } /* someone wrote to us, we should reload the timer */ tco_timer_keepalive(); } return len; } static long nv_tco_ioctl(struct file *file, unsigned int cmd, unsigned long arg) { int new_options, retval = -EINVAL; int new_heartbeat; void __user *argp = (void __user *)arg; int __user *p = argp; static const struct watchdog_info ident = { .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE, .firmware_version = 0, .identity = TCO_MODULE_NAME, }; switch (cmd) { case WDIOC_GETSUPPORT: return copy_to_user(argp, &ident, sizeof(ident)) ? -EFAULT : 0; case WDIOC_GETSTATUS: case WDIOC_GETBOOTSTATUS: return put_user(0, p); case WDIOC_SETOPTIONS: if (get_user(new_options, p)) return -EFAULT; if (new_options & WDIOS_DISABLECARD) { tco_timer_stop(); retval = 0; } if (new_options & WDIOS_ENABLECARD) { tco_timer_keepalive(); tco_timer_start(); retval = 0; } return retval; case WDIOC_KEEPALIVE: tco_timer_keepalive(); return 0; case WDIOC_SETTIMEOUT: if (get_user(new_heartbeat, p)) return -EFAULT; if (tco_timer_set_heartbeat(new_heartbeat)) return -EINVAL; tco_timer_keepalive(); /* Fall through */ case WDIOC_GETTIMEOUT: return put_user(heartbeat, p); default: return -ENOTTY; } } /* * Kernel Interfaces */ static const struct file_operations nv_tco_fops = { .owner = THIS_MODULE, .llseek = no_llseek, .write = nv_tco_write, .unlocked_ioctl = nv_tco_ioctl, .compat_ioctl = compat_ptr_ioctl, .open = nv_tco_open, .release = nv_tco_release, }; static struct miscdevice nv_tco_miscdev = { .minor = WATCHDOG_MINOR, .name = "watchdog", .fops = &nv_tco_fops, }; /* * Data for PCI driver interface * * This data only exists for exporting the supported * PCI ids via MODULE_DEVICE_TABLE. We do not actually * register a pci_driver, because someone else might one day * want to register another driver on the same PCI id. */ static const struct pci_device_id tco_pci_tbl[] = { { PCI_VENDOR_ID_NVIDIA, PCI_DEVICE_ID_NVIDIA_NFORCE_MCP51_SMBUS, PCI_ANY_ID, PCI_ANY_ID, }, { PCI_VENDOR_ID_NVIDIA, PCI_DEVICE_ID_NVIDIA_NFORCE_MCP55_SMBUS, PCI_ANY_ID, PCI_ANY_ID, }, { PCI_VENDOR_ID_NVIDIA, PCI_DEVICE_ID_NVIDIA_NFORCE_MCP78S_SMBUS, PCI_ANY_ID, PCI_ANY_ID, }, { PCI_VENDOR_ID_NVIDIA, PCI_DEVICE_ID_NVIDIA_NFORCE_MCP79_SMBUS, PCI_ANY_ID, PCI_ANY_ID, }, { 0, }, /* End of list */ }; MODULE_DEVICE_TABLE(pci, tco_pci_tbl); /* * Init & exit routines */ static unsigned char nv_tco_getdevice(void) { struct pci_dev *dev = NULL; u32 val; /* Find the PCI device */ for_each_pci_dev(dev) { if (pci_match_id(tco_pci_tbl, dev) != NULL) { tco_pci = dev; break; } } if (!tco_pci) return 0; /* Find the base io port */ pci_read_config_dword(tco_pci, 0x64, &val); val &= 0xffff; if (val == 0x0001 || val == 0x0000) { /* Something is wrong here, bar isn't setup */ pr_err("failed to get tcobase address\n"); return 0; } val &= 0xff00; tcobase = val + 0x40; if (!request_region(tcobase, 0x10, "NV TCO")) { pr_err("I/O address 0x%04x already in use\n", tcobase); return 0; } /* Set a reasonable heartbeat before we stop the timer */ tco_timer_set_heartbeat(30); /* * Stop the TCO before we change anything so we don't race with * a zeroed timer. */ tco_timer_keepalive(); tco_timer_stop(); /* Disable SMI caused by TCO */ if (!request_region(MCP51_SMI_EN(tcobase), 4, "NV TCO")) { pr_err("I/O address 0x%04x already in use\n", MCP51_SMI_EN(tcobase)); goto out; } val = inl(MCP51_SMI_EN(tcobase)); val &= ~MCP51_SMI_EN_TCO; outl(val, MCP51_SMI_EN(tcobase)); val = inl(MCP51_SMI_EN(tcobase)); release_region(MCP51_SMI_EN(tcobase), 4); if (val & MCP51_SMI_EN_TCO) { pr_err("Could not disable SMI caused by TCO\n"); goto out; } /* Check chipset's NO_REBOOT bit */ pci_read_config_dword(tco_pci, MCP51_SMBUS_SETUP_B, &val); val |= MCP51_SMBUS_SETUP_B_TCO_REBOOT; pci_write_config_dword(tco_pci, MCP51_SMBUS_SETUP_B, val); pci_read_config_dword(tco_pci, MCP51_SMBUS_SETUP_B, &val); if (!(val & MCP51_SMBUS_SETUP_B_TCO_REBOOT)) { pr_err("failed to reset NO_REBOOT flag, reboot disabled by hardware\n"); goto out; } return 1; out: release_region(tcobase, 0x10); return 0; } static int nv_tco_init(struct platform_device *dev) { int ret; /* Check whether or not the hardware watchdog is there */ if (!nv_tco_getdevice()) return -ENODEV; /* Check to see if last reboot was due to watchdog timeout */ pr_info("Watchdog reboot %sdetected\n", inl(TCO_STS(tcobase)) & TCO_STS_TCO2TO_STS ? "" : "not "); /* Clear out the old status */ outl(TCO_STS_RESET, TCO_STS(tcobase)); /* * Check that the heartbeat value is within it's range. * If not, reset to the default. */ if (tco_timer_set_heartbeat(heartbeat)) { heartbeat = WATCHDOG_HEARTBEAT; tco_timer_set_heartbeat(heartbeat); pr_info("heartbeat value must be 2<heartbeat<39, using %d\n", heartbeat); } ret = misc_register(&nv_tco_miscdev); if (ret != 0) { pr_err("cannot register miscdev on minor=%d (err=%d)\n", WATCHDOG_MINOR, ret); goto unreg_region; } clear_bit(0, &timer_alive); tco_timer_stop(); pr_info("initialized (0x%04x). heartbeat=%d sec (nowayout=%d)\n", tcobase, heartbeat, nowayout); return 0; unreg_region: release_region(tcobase, 0x10); return ret; } static void nv_tco_cleanup(void) { u32 val; /* Stop the timer before we leave */ if (!nowayout) tco_timer_stop(); /* Set the NO_REBOOT bit to prevent later reboots, just for sure */ pci_read_config_dword(tco_pci, MCP51_SMBUS_SETUP_B, &val); val &= ~MCP51_SMBUS_SETUP_B_TCO_REBOOT; pci_write_config_dword(tco_pci, MCP51_SMBUS_SETUP_B, val); pci_read_config_dword(tco_pci, MCP51_SMBUS_SETUP_B, &val); if (val & MCP51_SMBUS_SETUP_B_TCO_REBOOT) { pr_crit("Couldn't unset REBOOT bit. Machine may soon reset\n"); } /* Deregister */ misc_deregister(&nv_tco_miscdev); release_region(tcobase, 0x10); } static int nv_tco_remove(struct platform_device *dev) { if (tcobase) nv_tco_cleanup(); return 0; } static void nv_tco_shutdown(struct platform_device *dev) { u32 val; tco_timer_stop(); /* Some BIOSes fail the POST (once) if the NO_REBOOT flag is not * unset during shutdown. */ pci_read_config_dword(tco_pci, MCP51_SMBUS_SETUP_B, &val); val &= ~MCP51_SMBUS_SETUP_B_TCO_REBOOT; pci_write_config_dword(tco_pci, MCP51_SMBUS_SETUP_B, val); } static struct platform_driver nv_tco_driver = { .probe = nv_tco_init, .remove = nv_tco_remove, .shutdown = nv_tco_shutdown, .driver = { .name = TCO_MODULE_NAME, }, }; static int __init nv_tco_init_module(void) { int err; pr_info("NV TCO WatchDog Timer Driver v%s\n", TCO_VERSION); err = platform_driver_register(&nv_tco_driver); if (err) return err; nv_tco_platform_device = platform_device_register_simple( TCO_MODULE_NAME, -1, NULL, 0); if (IS_ERR(nv_tco_platform_device)) { err = PTR_ERR(nv_tco_platform_device); goto unreg_platform_driver; } return 0; unreg_platform_driver: platform_driver_unregister(&nv_tco_driver); return err; } static void __exit nv_tco_cleanup_module(void) { platform_device_unregister(nv_tco_platform_device); platform_driver_unregister(&nv_tco_driver); pr_info("NV TCO Watchdog Module Unloaded\n"); } module_init(nv_tco_init_module); module_exit(nv_tco_cleanup_module); MODULE_AUTHOR("Mike Waychison"); MODULE_DESCRIPTION("TCO timer driver for NV chipsets"); MODULE_LICENSE("GPL");