diff options
Diffstat (limited to 'drivers/watchdog/nv_tco.c')
| -rw-r--r-- | drivers/watchdog/nv_tco.c | 515 |
1 files changed, 515 insertions, 0 deletions
diff --git a/drivers/watchdog/nv_tco.c b/drivers/watchdog/nv_tco.c new file mode 100644 index 000000000..f6902a337 --- /dev/null +++ b/drivers/watchdog/nv_tco.c @@ -0,0 +1,515 @@ +// 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. + * https://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(); + fallthrough; + 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"); |