1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * VIA Chipset Watchdog Driver 4 * 5 * Copyright (C) 2011 Sigfox 6 * Author: Marc Vertes <marc.vertes@sigfox.com> 7 * Based on a preliminary version from Harald Welte <HaraldWelte@viatech.com> 8 * Timer code by Wim Van Sebroeck <wim@iguana.be> 9 * 10 * Caveat: PnP must be enabled in BIOS to allow full access to watchdog 11 * control registers. If not, the watchdog must be configured in BIOS manually. 12 */ 13 14 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 15 16 #include <linux/device.h> 17 #include <linux/io.h> 18 #include <linux/jiffies.h> 19 #include <linux/module.h> 20 #include <linux/pci.h> 21 #include <linux/timer.h> 22 #include <linux/watchdog.h> 23 24 /* Configuration registers relative to the pci device */ 25 #define VIA_WDT_MMIO_BASE 0xe8 /* MMIO region base address */ 26 #define VIA_WDT_CONF 0xec /* watchdog enable state */ 27 28 /* Relevant bits for the VIA_WDT_CONF register */ 29 #define VIA_WDT_CONF_ENABLE 0x01 /* 1: enable watchdog */ 30 #define VIA_WDT_CONF_MMIO 0x02 /* 1: enable watchdog MMIO */ 31 32 /* 33 * The MMIO region contains the watchdog control register and the 34 * hardware timer counter. 35 */ 36 #define VIA_WDT_MMIO_LEN 8 /* MMIO region length in bytes */ 37 #define VIA_WDT_CTL 0 /* MMIO addr+0: state/control reg. */ 38 #define VIA_WDT_COUNT 4 /* MMIO addr+4: timer counter reg. */ 39 40 /* Bits for the VIA_WDT_CTL register */ 41 #define VIA_WDT_RUNNING 0x01 /* 0: stop, 1: running */ 42 #define VIA_WDT_FIRED 0x02 /* 1: restarted by expired watchdog */ 43 #define VIA_WDT_PWROFF 0x04 /* 0: reset, 1: poweroff */ 44 #define VIA_WDT_DISABLED 0x08 /* 1: timer is disabled */ 45 #define VIA_WDT_TRIGGER 0x80 /* 1: start a new countdown */ 46 47 /* Hardware heartbeat in seconds */ 48 #define WDT_HW_HEARTBEAT 1 49 50 /* Timer heartbeat (500ms) */ 51 #define WDT_HEARTBEAT (HZ/2) /* should be <= ((WDT_HW_HEARTBEAT*HZ)/2) */ 52 53 /* User space timeout in seconds */ 54 #define WDT_TIMEOUT_MAX 1023 /* approx. 17 min. */ 55 #define WDT_TIMEOUT 60 56 static int timeout = WDT_TIMEOUT; 57 module_param(timeout, int, 0); 58 MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds, between 1 and 1023 " 59 "(default = " __MODULE_STRING(WDT_TIMEOUT) ")"); 60 61 static bool nowayout = WATCHDOG_NOWAYOUT; 62 module_param(nowayout, bool, 0); 63 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started " 64 "(default = " __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); 65 66 static struct watchdog_device wdt_dev; 67 static struct resource wdt_res; 68 static void __iomem *wdt_mem; 69 static unsigned int mmio; 70 static void wdt_timer_tick(struct timer_list *unused); 71 static DEFINE_TIMER(timer, wdt_timer_tick); 72 /* The timer that pings the watchdog */ 73 static unsigned long next_heartbeat; /* the next_heartbeat for the timer */ 74 75 static inline void wdt_reset(void) 76 { 77 unsigned int ctl = readl(wdt_mem); 78 79 writel(ctl | VIA_WDT_TRIGGER, wdt_mem); 80 } 81 82 /* 83 * Timer tick: the timer will make sure that the watchdog timer hardware 84 * is being reset in time. The conditions to do this are: 85 * 1) the watchdog timer has been started and /dev/watchdog is open 86 * and there is still time left before userspace should send the 87 * next heartbeat/ping. (note: the internal heartbeat is much smaller 88 * then the external/userspace heartbeat). 89 * 2) the watchdog timer has been stopped by userspace. 90 */ 91 static void wdt_timer_tick(struct timer_list *unused) 92 { 93 if (time_before(jiffies, next_heartbeat) || 94 (!watchdog_active(&wdt_dev))) { 95 wdt_reset(); 96 mod_timer(&timer, jiffies + WDT_HEARTBEAT); 97 } else 98 pr_crit("I will reboot your machine !\n"); 99 } 100 101 static int wdt_ping(struct watchdog_device *wdd) 102 { 103 /* calculate when the next userspace timeout will be */ 104 next_heartbeat = jiffies + wdd->timeout * HZ; 105 return 0; 106 } 107 108 static int wdt_start(struct watchdog_device *wdd) 109 { 110 unsigned int ctl = readl(wdt_mem); 111 112 writel(wdd->timeout, wdt_mem + VIA_WDT_COUNT); 113 writel(ctl | VIA_WDT_RUNNING | VIA_WDT_TRIGGER, wdt_mem); 114 wdt_ping(wdd); 115 mod_timer(&timer, jiffies + WDT_HEARTBEAT); 116 return 0; 117 } 118 119 static int wdt_stop(struct watchdog_device *wdd) 120 { 121 unsigned int ctl = readl(wdt_mem); 122 123 writel(ctl & ~VIA_WDT_RUNNING, wdt_mem); 124 return 0; 125 } 126 127 static int wdt_set_timeout(struct watchdog_device *wdd, 128 unsigned int new_timeout) 129 { 130 writel(new_timeout, wdt_mem + VIA_WDT_COUNT); 131 wdd->timeout = new_timeout; 132 return 0; 133 } 134 135 static const struct watchdog_info wdt_info = { 136 .identity = "VIA watchdog", 137 .options = WDIOF_CARDRESET | 138 WDIOF_SETTIMEOUT | 139 WDIOF_MAGICCLOSE | 140 WDIOF_KEEPALIVEPING, 141 }; 142 143 static const struct watchdog_ops wdt_ops = { 144 .owner = THIS_MODULE, 145 .start = wdt_start, 146 .stop = wdt_stop, 147 .ping = wdt_ping, 148 .set_timeout = wdt_set_timeout, 149 }; 150 151 static struct watchdog_device wdt_dev = { 152 .info = &wdt_info, 153 .ops = &wdt_ops, 154 .min_timeout = 1, 155 .max_timeout = WDT_TIMEOUT_MAX, 156 }; 157 158 static int wdt_probe(struct pci_dev *pdev, 159 const struct pci_device_id *ent) 160 { 161 unsigned char conf; 162 int ret = -ENODEV; 163 164 if (pci_enable_device(pdev)) { 165 dev_err(&pdev->dev, "cannot enable PCI device\n"); 166 return -ENODEV; 167 } 168 169 /* 170 * Allocate a MMIO region which contains watchdog control register 171 * and counter, then configure the watchdog to use this region. 172 * This is possible only if PnP is properly enabled in BIOS. 173 * If not, the watchdog must be configured in BIOS manually. 174 */ 175 if (allocate_resource(&iomem_resource, &wdt_res, VIA_WDT_MMIO_LEN, 176 0xf0000000, 0xffffff00, 0xff, NULL, NULL)) { 177 dev_err(&pdev->dev, "MMIO allocation failed\n"); 178 goto err_out_disable_device; 179 } 180 181 pci_write_config_dword(pdev, VIA_WDT_MMIO_BASE, wdt_res.start); 182 pci_read_config_byte(pdev, VIA_WDT_CONF, &conf); 183 conf |= VIA_WDT_CONF_ENABLE | VIA_WDT_CONF_MMIO; 184 pci_write_config_byte(pdev, VIA_WDT_CONF, conf); 185 186 pci_read_config_dword(pdev, VIA_WDT_MMIO_BASE, &mmio); 187 if (mmio) { 188 dev_info(&pdev->dev, "VIA Chipset watchdog MMIO: %x\n", mmio); 189 } else { 190 dev_err(&pdev->dev, "MMIO setting failed. Check BIOS.\n"); 191 goto err_out_resource; 192 } 193 194 if (!request_mem_region(mmio, VIA_WDT_MMIO_LEN, "via_wdt")) { 195 dev_err(&pdev->dev, "MMIO region busy\n"); 196 goto err_out_resource; 197 } 198 199 wdt_mem = ioremap(mmio, VIA_WDT_MMIO_LEN); 200 if (wdt_mem == NULL) { 201 dev_err(&pdev->dev, "cannot remap VIA wdt MMIO registers\n"); 202 goto err_out_release; 203 } 204 205 if (timeout < 1 || timeout > WDT_TIMEOUT_MAX) 206 timeout = WDT_TIMEOUT; 207 208 wdt_dev.timeout = timeout; 209 wdt_dev.parent = &pdev->dev; 210 watchdog_set_nowayout(&wdt_dev, nowayout); 211 if (readl(wdt_mem) & VIA_WDT_FIRED) 212 wdt_dev.bootstatus |= WDIOF_CARDRESET; 213 214 ret = watchdog_register_device(&wdt_dev); 215 if (ret) 216 goto err_out_iounmap; 217 218 /* start triggering, in case of watchdog already enabled by BIOS */ 219 mod_timer(&timer, jiffies + WDT_HEARTBEAT); 220 return 0; 221 222 err_out_iounmap: 223 iounmap(wdt_mem); 224 err_out_release: 225 release_mem_region(mmio, VIA_WDT_MMIO_LEN); 226 err_out_resource: 227 release_resource(&wdt_res); 228 err_out_disable_device: 229 pci_disable_device(pdev); 230 return ret; 231 } 232 233 static void wdt_remove(struct pci_dev *pdev) 234 { 235 watchdog_unregister_device(&wdt_dev); 236 del_timer_sync(&timer); 237 iounmap(wdt_mem); 238 release_mem_region(mmio, VIA_WDT_MMIO_LEN); 239 release_resource(&wdt_res); 240 pci_disable_device(pdev); 241 } 242 243 static const struct pci_device_id wdt_pci_table[] = { 244 { PCI_DEVICE(PCI_VENDOR_ID_VIA, PCI_DEVICE_ID_VIA_CX700) }, 245 { PCI_DEVICE(PCI_VENDOR_ID_VIA, PCI_DEVICE_ID_VIA_VX800) }, 246 { PCI_DEVICE(PCI_VENDOR_ID_VIA, PCI_DEVICE_ID_VIA_VX855) }, 247 { 0 } 248 }; 249 250 static struct pci_driver wdt_driver = { 251 .name = "via_wdt", 252 .id_table = wdt_pci_table, 253 .probe = wdt_probe, 254 .remove = wdt_remove, 255 }; 256 257 module_pci_driver(wdt_driver); 258 259 MODULE_AUTHOR("Marc Vertes"); 260 MODULE_DESCRIPTION("Driver for watchdog timer on VIA chipset"); 261 MODULE_LICENSE("GPL"); 262