// SPDX-License-Identifier: GPL-2.0-only /* * VIA Chipset Watchdog Driver * * Copyright (C) 2011 Sigfox * Author: Marc Vertes <marc.vertes@sigfox.com> * Based on a preliminary version from Harald Welte <HaraldWelte@viatech.com> * Timer code by Wim Van Sebroeck <wim@iguana.be> * * Caveat: PnP must be enabled in BIOS to allow full access to watchdog * control registers. If not, the watchdog must be configured in BIOS manually. */ #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt #include <linux/device.h> #include <linux/io.h> #include <linux/jiffies.h> #include <linux/module.h> #include <linux/pci.h> #include <linux/timer.h> #include <linux/watchdog.h> /* Configuration registers relative to the pci device */ #define VIA_WDT_MMIO_BASE 0xe8 /* MMIO region base address */ #define VIA_WDT_CONF 0xec /* watchdog enable state */ /* Relevant bits for the VIA_WDT_CONF register */ #define VIA_WDT_CONF_ENABLE 0x01 /* 1: enable watchdog */ #define VIA_WDT_CONF_MMIO 0x02 /* 1: enable watchdog MMIO */ /* * The MMIO region contains the watchdog control register and the * hardware timer counter. */ #define VIA_WDT_MMIO_LEN 8 /* MMIO region length in bytes */ #define VIA_WDT_CTL 0 /* MMIO addr+0: state/control reg. */ #define VIA_WDT_COUNT 4 /* MMIO addr+4: timer counter reg. */ /* Bits for the VIA_WDT_CTL register */ #define VIA_WDT_RUNNING 0x01 /* 0: stop, 1: running */ #define VIA_WDT_FIRED 0x02 /* 1: restarted by expired watchdog */ #define VIA_WDT_PWROFF 0x04 /* 0: reset, 1: poweroff */ #define VIA_WDT_DISABLED 0x08 /* 1: timer is disabled */ #define VIA_WDT_TRIGGER 0x80 /* 1: start a new countdown */ /* Hardware heartbeat in seconds */ #define WDT_HW_HEARTBEAT 1 /* Timer heartbeat (500ms) */ #define WDT_HEARTBEAT (HZ/2) /* should be <= ((WDT_HW_HEARTBEAT*HZ)/2) */ /* User space timeout in seconds */ #define WDT_TIMEOUT_MAX 1023 /* approx. 17 min. */ #define WDT_TIMEOUT 60 static int timeout = WDT_TIMEOUT; module_param(timeout, int, 0); MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds, between 1 and 1023 " "(default = " __MODULE_STRING(WDT_TIMEOUT) ")"); 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 watchdog_device wdt_dev; static struct resource wdt_res; static void __iomem *wdt_mem; static unsigned int mmio; static void wdt_timer_tick(struct timer_list *unused); static DEFINE_TIMER(timer, wdt_timer_tick); /* The timer that pings the watchdog */ static unsigned long next_heartbeat; /* the next_heartbeat for the timer */ static inline void wdt_reset(void) { unsigned int ctl = readl(wdt_mem); writel(ctl | VIA_WDT_TRIGGER, wdt_mem); } /* * Timer tick: the timer will make sure that the watchdog timer hardware * is being reset in time. The conditions to do this are: * 1) the watchdog timer has been started and /dev/watchdog is open * and there is still time left before userspace should send the * next heartbeat/ping. (note: the internal heartbeat is much smaller * then the external/userspace heartbeat). * 2) the watchdog timer has been stopped by userspace. */ static void wdt_timer_tick(struct timer_list *unused) { if (time_before(jiffies, next_heartbeat) || (!watchdog_active(&wdt_dev))) { wdt_reset(); mod_timer(&timer, jiffies + WDT_HEARTBEAT); } else pr_crit("I will reboot your machine !\n"); } static int wdt_ping(struct watchdog_device *wdd) { /* calculate when the next userspace timeout will be */ next_heartbeat = jiffies + wdd->timeout * HZ; return 0; } static int wdt_start(struct watchdog_device *wdd) { unsigned int ctl = readl(wdt_mem); writel(wdd->timeout, wdt_mem + VIA_WDT_COUNT); writel(ctl | VIA_WDT_RUNNING | VIA_WDT_TRIGGER, wdt_mem); wdt_ping(wdd); mod_timer(&timer, jiffies + WDT_HEARTBEAT); return 0; } static int wdt_stop(struct watchdog_device *wdd) { unsigned int ctl = readl(wdt_mem); writel(ctl & ~VIA_WDT_RUNNING, wdt_mem); return 0; } static int wdt_set_timeout(struct watchdog_device *wdd, unsigned int new_timeout) { writel(new_timeout, wdt_mem + VIA_WDT_COUNT); wdd->timeout = new_timeout; return 0; } static const struct watchdog_info wdt_info = { .identity = "VIA watchdog", .options = WDIOF_CARDRESET | WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING, }; static const struct watchdog_ops wdt_ops = { .owner = THIS_MODULE, .start = wdt_start, .stop = wdt_stop, .ping = wdt_ping, .set_timeout = wdt_set_timeout, }; static struct watchdog_device wdt_dev = { .info = &wdt_info, .ops = &wdt_ops, .min_timeout = 1, .max_timeout = WDT_TIMEOUT_MAX, }; static int wdt_probe(struct pci_dev *pdev, const struct pci_device_id *ent) { unsigned char conf; int ret = -ENODEV; if (pci_enable_device(pdev)) { dev_err(&pdev->dev, "cannot enable PCI device\n"); return -ENODEV; } /* * Allocate a MMIO region which contains watchdog control register * and counter, then configure the watchdog to use this region. * This is possible only if PnP is properly enabled in BIOS. * If not, the watchdog must be configured in BIOS manually. */ if (allocate_resource(&iomem_resource, &wdt_res, VIA_WDT_MMIO_LEN, 0xf0000000, 0xffffff00, 0xff, NULL, NULL)) { dev_err(&pdev->dev, "MMIO allocation failed\n"); goto err_out_disable_device; } pci_write_config_dword(pdev, VIA_WDT_MMIO_BASE, wdt_res.start); pci_read_config_byte(pdev, VIA_WDT_CONF, &conf); conf |= VIA_WDT_CONF_ENABLE | VIA_WDT_CONF_MMIO; pci_write_config_byte(pdev, VIA_WDT_CONF, conf); pci_read_config_dword(pdev, VIA_WDT_MMIO_BASE, &mmio); if (mmio) { dev_info(&pdev->dev, "VIA Chipset watchdog MMIO: %x\n", mmio); } else { dev_err(&pdev->dev, "MMIO setting failed. Check BIOS.\n"); goto err_out_resource; } if (!request_mem_region(mmio, VIA_WDT_MMIO_LEN, "via_wdt")) { dev_err(&pdev->dev, "MMIO region busy\n"); goto err_out_resource; } wdt_mem = ioremap(mmio, VIA_WDT_MMIO_LEN); if (wdt_mem == NULL) { dev_err(&pdev->dev, "cannot remap VIA wdt MMIO registers\n"); goto err_out_release; } if (timeout < 1 || timeout > WDT_TIMEOUT_MAX) timeout = WDT_TIMEOUT; wdt_dev.timeout = timeout; wdt_dev.parent = &pdev->dev; watchdog_set_nowayout(&wdt_dev, nowayout); if (readl(wdt_mem) & VIA_WDT_FIRED) wdt_dev.bootstatus |= WDIOF_CARDRESET; ret = watchdog_register_device(&wdt_dev); if (ret) goto err_out_iounmap; /* start triggering, in case of watchdog already enabled by BIOS */ mod_timer(&timer, jiffies + WDT_HEARTBEAT); return 0; err_out_iounmap: iounmap(wdt_mem); err_out_release: release_mem_region(mmio, VIA_WDT_MMIO_LEN); err_out_resource: release_resource(&wdt_res); err_out_disable_device: pci_disable_device(pdev); return ret; } static void wdt_remove(struct pci_dev *pdev) { watchdog_unregister_device(&wdt_dev); del_timer_sync(&timer); iounmap(wdt_mem); release_mem_region(mmio, VIA_WDT_MMIO_LEN); release_resource(&wdt_res); pci_disable_device(pdev); } static const struct pci_device_id wdt_pci_table[] = { { PCI_DEVICE(PCI_VENDOR_ID_VIA, PCI_DEVICE_ID_VIA_CX700) }, { PCI_DEVICE(PCI_VENDOR_ID_VIA, PCI_DEVICE_ID_VIA_VX800) }, { PCI_DEVICE(PCI_VENDOR_ID_VIA, PCI_DEVICE_ID_VIA_VX855) }, { 0 } }; static struct pci_driver wdt_driver = { .name = "via_wdt", .id_table = wdt_pci_table, .probe = wdt_probe, .remove = wdt_remove, }; module_pci_driver(wdt_driver); MODULE_AUTHOR("Marc Vertes"); MODULE_DESCRIPTION("Driver for watchdog timer on VIA chipset"); MODULE_LICENSE("GPL");