1/* 2 * Watchdog for the 7101 PMU version found in the ALi1535 chipsets 3 * 4 * This program is free software; you can redistribute it and/or 5 * modify it under the terms of the GNU General Public License 6 * as published by the Free Software Foundation; either version 7 * 2 of the License, or (at your option) any later version. 8 */ 9 10#include <linux/module.h> 11#include <linux/types.h> 12#include <linux/kernel.h> 13#include <linux/fs.h> 14#include <linux/mm.h> 15#include <linux/miscdevice.h> 16#include <linux/watchdog.h> 17#include <linux/reboot.h> 18#include <linux/init.h> 19#include <linux/pci.h> 20#include <linux/ioport.h> 21#include <asm/uaccess.h> 22#include <asm/io.h> 23 24static spinlock_t ali_lock; /* Guards the hardware */ 25 26#ifdef CONFIG_WATCHDOG_NOWAYOUT 27static int nowayout = 1; 28#else 29static int nowayout = 0; 30#endif 31 32MODULE_PARM(nowayout,"i"); 33MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=CONFIG_WATCHDOG_NOWAYOUT)"); 34 35static unsigned long timer_alive; 36static char ali_expect_close; 37static u32 ali_timeout = 60; /* 60 seconds */ 38static u32 ali_timeout_bits = 1 | (1<<7); /* 1 count in minutes */ 39 40static struct pci_dev *ali_pci; 41 42/** 43 * ali_timer_start - start watchdog countdown 44 * @dev: PCI device of the PMU 45 * 46 * Starts the timer running providing the timer has a counter 47 * configuration set. 48 */ 49 50static void ali_timer_start(struct pci_dev *pdev) 51{ 52 u32 val; 53 54 spin_lock(&ali_lock); 55 56 pci_read_config_dword(pdev, 0xCC, &val); 57 val &= ~0x3F; /* Mask count */ 58 val |= (1<<25) | ali_timeout_bits; 59 pci_write_config_dword(pdev, 0xCC, val); 60 spin_unlock(&ali_lock); 61} 62 63/** 64 * ali_timer_stop - stop the timer countdown 65 * @pdev: PCI device of the PMU 66 * 67 * Stop the ALi watchdog countdown 68 */ 69 70static void ali_timer_stop (struct pci_dev *pdev) 71{ 72 u32 val; 73 74 spin_lock(&ali_lock); 75 pci_read_config_dword(pdev, 0xCC, &val); 76 val &= ~0x3F; /* Mask count to zero (disabled) */ 77 val &= ~(1<<25);/* and for safety mask the reset enable */ 78 pci_write_config_dword(pdev, 0xCC, val); 79 spin_unlock(&ali_lock); 80} 81 82/** 83 * ali_timer_settimer - compute the timer reload value 84 * @pdev: PCI device of the PMU 85 * @t: time in seconds 86 * 87 * Computes the timeout values needed and then restarts the timer 88 * running with the new timeout values 89 */ 90 91static int ali_timer_settimer(struct pci_dev *pdev, unsigned long t) 92{ 93 if(t < 60) 94 ali_timeout_bits = t|(1<<6); 95 else if(t < 3600) 96 ali_timeout_bits = (t/60)|(1<<7); 97 else if(t < 18000) 98 ali_timeout_bits = (t/300)|(1<<6)|(1<<7); 99 else return -EINVAL; 100 101 ali_timeout = t; 102 ali_timer_start(pdev); 103 return 0; 104} 105 106/** 107 * ali_open - handle open of ali watchdog 108 * @inode: inode from VFS 109 * @file: file from VFS 110 * 111 * Open the ALi watchdog device. Ensure only one person opens it 112 * at a time. Also start the watchdog running. 113 */ 114 115static int ali_open(struct inode *inode, struct file *file) 116{ 117 if (test_and_set_bit(0, &timer_alive)) 118 return -EBUSY; 119 ali_timer_start (ali_pci); 120 return 0; 121} 122 123/** 124 * ali_release - close an ALi watchdog 125 * @inode: inode from VFS 126 * @file: file from VFS 127 * 128 * Close the ALi watchdog device. Actual shutdown of the timer 129 * only occurs if the magic sequence has been set or nowayout is 130 * disabled 131 */ 132 133static int ali_release (struct inode *inode, struct file *file) 134{ 135 /* 136 * Shut off the timer. 137 */ 138 if (ali_expect_close == 42 && !nowayout) { 139 ali_timer_stop(ali_pci); 140 } else { 141 ali_timer_start(ali_pci); 142 printk(KERN_CRIT "ali1535_wdt: Unexpected close, not stopping watchdog!\n"); 143 } 144 clear_bit(0, &timer_alive); 145 ali_expect_close = 0; 146 return 0; 147} 148 149/** 150 * ali_write - writes to ALi watchdog 151 * @file: file from VFS 152 * @data: user address of data 153 * @len: length of data 154 * @ppos: pointer to the file offset 155 * 156 * Handle a write to the ALi watchdog. Writing to the file pings 157 * the watchdog and resets it. Writing the magic 'V' sequence allows 158 * the next close to turn off the watchdog. 159 */ 160 161static ssize_t ali_write (struct file *file, const char *data, 162 size_t len, loff_t * ppos) 163{ 164 /* Can't seek (pwrite) on this device */ 165 if (ppos != &file->f_pos) 166 return -ESPIPE; 167 168 /* See if we got the magic character 'V' and reload the timer */ 169 if (len) { 170 size_t i; 171 172 ali_expect_close = 0; 173 174 /* scan to see wether or not we got the magic character */ 175 for (i = 0; i != len; i++) { 176 u8 c; 177 if(get_user(c, data+i)) 178 return -EFAULT; 179 if (c == 'V') 180 ali_expect_close = 42; 181 } 182 183 /* someone wrote to us, we should reload the timer */ 184 ali_timer_start(ali_pci); 185 return 1; 186 } 187 return 0; 188} 189 190/** 191 * ali_ioctl - handle watchdog ioctls 192 * @inode: VFS inode 193 * @file: VFS file pointer 194 * @cmd: ioctl number 195 * @arg: arguments to the ioctl 196 * 197 * Handle the watchdog ioctls supported by the ALi driver. Really 198 * we want an extension to enable irq ack monitoring and the like 199 */ 200 201static int ali_ioctl (struct inode *inode, struct file *file, 202 unsigned int cmd, unsigned long arg) 203{ 204 int options, retval = -EINVAL; 205 u32 t; 206 static struct watchdog_info ident = { 207 options: WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING, 208 firmware_version: 0, 209 identity: "ALi 1535D+ TCO timer", 210 }; 211 switch (cmd) { 212 default: 213 return -ENOTTY; 214 case WDIOC_GETSUPPORT: 215 if (copy_to_user((struct watchdog_info *) arg, &ident, sizeof (ident))) 216 return -EFAULT; 217 return 0; 218 case WDIOC_GETSTATUS: 219 case WDIOC_GETBOOTSTATUS: 220 return put_user(0, (int *) arg); 221 case WDIOC_SETOPTIONS: 222 if (get_user (options, (int *) arg)) 223 return -EFAULT; 224 if (options & WDIOS_DISABLECARD) { 225 ali_timer_stop(ali_pci); 226 retval = 0; 227 } 228 if (options & WDIOS_ENABLECARD) { 229 ali_timer_start(ali_pci); 230 retval = 0; 231 } 232 return retval; 233 case WDIOC_KEEPALIVE: 234 ali_timer_start(ali_pci); 235 return 0; 236 case WDIOC_SETTIMEOUT: 237 if (get_user(t, (int *) arg)) 238 return -EFAULT; 239 if (ali_timer_settimer(ali_pci, t)) 240 return -EINVAL; 241 ali_timer_start(ali_pci); 242 /* Fall */ 243 case WDIOC_GETTIMEOUT: 244 return put_user(ali_timeout, (int *)arg); 245 } 246} 247 248/* 249 * Data for PCI driver interface 250 * 251 * This data only exists for exporting the supported 252 * PCI ids via MODULE_DEVICE_TABLE. We do not actually 253 * register a pci_driver, because someone else might one day 254 * want to register another driver on the same PCI id. 255 */ 256 257static struct pci_device_id ali_pci_tbl[] __initdata = { 258 { PCI_VENDOR_ID_AL, 1535, PCI_ANY_ID, PCI_ANY_ID,}, 259 { 0, }, 260}; 261MODULE_DEVICE_TABLE (pci, ali_pci_tbl); 262 263 264/** 265 * ali_find_watchdog - find a 1535 and 7101 266 * 267 * Scans the PCI hardware for a 1535 series bridge and matching 7101 268 * watchdog device. This may be overtight but it is better to be safe 269 */ 270 271static int __init ali_find_watchdog(void) 272{ 273 struct pci_dev *pdev; 274 u32 wdog; 275 276 /* Check for a 1535 series bridge */ 277 pdev = pci_find_device(PCI_VENDOR_ID_AL, 0x1535, NULL); 278 if(pdev == NULL) 279 return -ENODEV; 280 281 /* Check for the a 7101 PMU */ 282 pdev = pci_find_device(PCI_VENDOR_ID_AL, 0x7101, NULL); 283 if(pdev == NULL) 284 return -ENODEV; 285 286 if(pci_enable_device(pdev)) 287 return -EIO; 288 289 ali_pci = pdev; 290 291 /* 292 * Initialize the timer bits 293 */ 294 295 pci_read_config_dword(pdev, 0xCC, &wdog); 296 297 wdog &= ~0x3F; /* Timer bits */ 298 wdog &= ~((1<<27)|(1<<26)|(1<<25)|(1<<24)); /* Issued events */ 299 wdog &= ~((1<<16)|(1<<13)|(1<<12)|(1<<11)|(1<<10)|(1<<9)); /* No monitor bits */ 300 301 pci_write_config_dword(pdev, 0xCC, wdog); 302 return 0; 303} 304 305static struct file_operations ali_fops = { 306 owner: THIS_MODULE, 307 write: ali_write, 308 ioctl: ali_ioctl, 309 open: ali_open, 310 release: ali_release, 311}; 312 313static struct miscdevice ali_miscdev = { 314 minor: WATCHDOG_MINOR, 315 name: "watchdog", 316 fops: &ali_fops, 317}; 318 319/** 320 * watchdog_init - module initialiser 321 * 322 * Scan for a suitable watchdog and if so initialize it. Return an error 323 * if we cannot, the error causes the module to unload 324 */ 325 326static int __init watchdog_init (void) 327{ 328 spin_lock_init(&ali_lock); 329 if (!ali_find_watchdog()) 330 return -ENODEV; 331 if (misc_register (&ali_miscdev) != 0) { 332 printk (KERN_ERR "alim1535d: cannot register watchdog device node.\n"); 333 return -EIO; 334 } 335 return 0; 336} 337 338/** 339 * watchdog_cleanup - unload watchdog 340 * 341 * Called on the unload of a successfully installed watchdog module. 342 */ 343 344static void __exit watchdog_cleanup (void) 345{ 346 ali_timer_stop(ali_pci); 347 misc_deregister (&ali_miscdev); 348} 349 350module_init(watchdog_init); 351module_exit(watchdog_cleanup); 352 353MODULE_AUTHOR("Alan Cox"); 354MODULE_DESCRIPTION("Watchdog driver for the ALi 1535+ PMU"); 355MODULE_LICENSE("GPL"); 356EXPORT_NO_SYMBOLS; 357