drivers/char/watchdog/pnx4008_wdt.c

   1 /*
   2  * drivers/char/watchdog/pnx4008_wdt.c
   3  *
   4  * Watchdog driver for PNX4008 board
   5  *
   6  * Authors: Dmitry Chigirev <source@mvista.com>,
   7  *          Vitaly Wool <vitalywool@gmail.com>
   8  * Based on sa1100 driver,
   9  * Copyright (C) 2000 Oleg Drokin <green@crimea.edu>
  10  *
  11  * 2005-2006 (c) MontaVista Software, Inc. This file is licensed under
  12  * the terms of the GNU General Public License version 2. This program
  13  * is licensed "as is" without any warranty of any kind, whether express
  14  * or implied.
  15  */
  16
  17 #include <linux/config.h>
  18 #include <linux/module.h>
  19 #include <linux/moduleparam.h>
  20 #include <linux/types.h>
  21 #include <linux/kernel.h>
  22 #include <linux/fs.h>
  23 #include <linux/miscdevice.h>
  24 #include <linux/watchdog.h>
  25 #include <linux/init.h>
  26 #include <linux/bitops.h>
  27 #include <linux/ioport.h>
  28 #include <linux/device.h>
  29 #include <linux/platform_device.h>
  30 #include <linux/clk.h>
  31 #include <linux/spinlock.h>
  32
  33 #include <asm/hardware.h>
  34 #include <asm/uaccess.h>
  35 #include <asm/io.h>
  36
  37 #define MODULE_NAME "PNX4008-WDT: "
  38
  39 /* WatchDog Timer - Chapter 23 Page 207 */
  40
  41 #define DEFAULT_HEARTBEAT 19
  42 #define MAX_HEARTBEAT     60
  43
  44 /* Watchdog timer register set definition */
  45 #define WDTIM_INT(p)     ((p) + 0x0)
  46 #define WDTIM_CTRL(p)    ((p) + 0x4)
  47 #define WDTIM_COUNTER(p) ((p) + 0x8)
  48 #define WDTIM_MCTRL(p)   ((p) + 0xC)
  49 #define WDTIM_MATCH0(p)  ((p) + 0x10)
  50 #define WDTIM_EMR(p)     ((p) + 0x14)
  51 #define WDTIM_PULSE(p)   ((p) + 0x18)
  52 #define WDTIM_RES(p)     ((p) + 0x1C)
  53
  54 /* WDTIM_INT bit definitions */
  55 #define MATCH_INT      1
  56
  57 /* WDTIM_CTRL bit definitions */
  58 #define COUNT_ENAB     1
  59 #define RESET_COUNT    (1<<1)
  60 #define DEBUG_EN       (1<<2)
  61
  62 /* WDTIM_MCTRL bit definitions */
  63 #define MR0_INT        1
  64 #undef  RESET_COUNT0
  65 #define RESET_COUNT0   (1<<2)
  66 #define STOP_COUNT0    (1<<2)
  67 #define M_RES1         (1<<3)
  68 #define M_RES2         (1<<4)
  69 #define RESFRC1        (1<<5)
  70 #define RESFRC2        (1<<6)
  71
  72 /* WDTIM_EMR bit definitions */
  73 #define EXT_MATCH0      1
  74 #define MATCH_OUTPUT_HIGH (2<<4)        /*a MATCH_CTRL setting */
  75
  76 /* WDTIM_RES bit definitions */
  77 #define WDOG_RESET      1       /* read only */
  78
  79 #define WDOG_COUNTER_RATE 13000000      /*the counter clock is 13 MHz fixed */
  80
  81 static int nowayout = WATCHDOG_NOWAYOUT;
  82 static int heartbeat = DEFAULT_HEARTBEAT;
  83
  84 static spinlock_t io_lock;
  85 static unsigned long wdt_status;
  86 #define WDT_IN_USE        0
  87 #define WDT_OK_TO_CLOSE   1
  88 #define WDT_REGION_INITED 2
  89 #define WDT_DEVICE_INITED 3
  90
  91 static unsigned long boot_status;
  92
  93 static struct resource  *wdt_mem;
  94 static void __iomem     *wdt_base;
  95 struct clk              *wdt_clk;
  96
  97 static void wdt_enable(void)
  98 {
  99         spin_lock(&io_lock);
 100
 101         if (wdt_clk)
 102                 clk_set_rate(wdt_clk, 1);
 103
 104         /* stop counter, initiate counter reset */
 105         __raw_writel(RESET_COUNT, WDTIM_CTRL(wdt_base));
 106         /*wait for reset to complete. 100% guarantee event */
 107         while (__raw_readl(WDTIM_COUNTER(wdt_base)))
 108                 cpu_relax();
 109         /* internal and external reset, stop after that */
 110         __raw_writel(M_RES2 | STOP_COUNT0 | RESET_COUNT0,
 111                 WDTIM_MCTRL(wdt_base));
 112         /* configure match output */
 113         __raw_writel(MATCH_OUTPUT_HIGH, WDTIM_EMR(wdt_base));
 114         /* clear interrupt, just in case */
 115         __raw_writel(MATCH_INT, WDTIM_INT(wdt_base));
 116         /* the longest pulse period 65541/(13*10^6) seconds ~ 5 ms. */
 117         __raw_writel(0xFFFF, WDTIM_PULSE(wdt_base));
 118         __raw_writel(heartbeat * WDOG_COUNTER_RATE, WDTIM_MATCH0(wdt_base));
 119         /*enable counter, stop when debugger active */
 120         __raw_writel(COUNT_ENAB | DEBUG_EN, WDTIM_CTRL(wdt_base));
 121
 122         spin_unlock(&io_lock);
 123 }
 124
 125 static void wdt_disable(void)
 126 {
 127         spin_lock(&io_lock);
 128
 129         __raw_writel(0, WDTIM_CTRL(wdt_base));  /*stop counter */
 130         if (wdt_clk)
 131                 clk_set_rate(wdt_clk, 0);
 132
 133         spin_unlock(&io_lock);
 134 }
 135
 136 static int pnx4008_wdt_open(struct inode *inode, struct file *file)
 137 {
 138         if (test_and_set_bit(WDT_IN_USE, &wdt_status))
 139                 return -EBUSY;
 140
 141         clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
 142
 143         wdt_enable();
 144
 145         return nonseekable_open(inode, file);
 146 }
 147
 148 static ssize_t
 149 pnx4008_wdt_write(struct file *file, const char *data, size_t len,
 150                   loff_t * ppos)
 151 {
 152         /*  Can't seek (pwrite) on this device  */
 153         if (ppos != &file->f_pos)
 154                 return -ESPIPE;
 155
 156         if (len) {
 157                 if (!nowayout) {
 158                         size_t i;
 159
 160                         clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
 161
 162                         for (i = 0; i != len; i++) {
 163                                 char c;
 164
 165                                 if (get_user(c, data + i))
 166                                         return -EFAULT;
 167                                 if (c == 'V')
 168                                         set_bit(WDT_OK_TO_CLOSE, &wdt_status);
 169                         }
 170                 }
 171                 wdt_enable();
 172         }
 173
 174         return len;
 175 }
 176
 177 static struct watchdog_info ident = {
 178         .options = WDIOF_CARDRESET | WDIOF_MAGICCLOSE |
 179             WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
 180         .identity = "PNX4008 Watchdog",
 181 };
 182
 183 static int
 184 pnx4008_wdt_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
 185                   unsigned long arg)
 186 {
 187         int ret = -ENOTTY;
 188         int time;
 189
 190         switch (cmd) {
 191         case WDIOC_GETSUPPORT:
 192                 ret = copy_to_user((struct watchdog_info *)arg, &ident,
 193                                    sizeof(ident)) ? -EFAULT : 0;
 194                 break;
 195
 196         case WDIOC_GETSTATUS:
 197                 ret = put_user(0, (int *)arg);
 198                 break;
 199
 200         case WDIOC_GETBOOTSTATUS:
 201                 ret = put_user(boot_status, (int *)arg);
 202                 break;
 203
 204         case WDIOC_SETTIMEOUT:
 205                 ret = get_user(time, (int *)arg);
 206                 if (ret)
 207                         break;
 208
 209                 if (time <= 0 || time > MAX_HEARTBEAT) {
 210                         ret = -EINVAL;
 211                         break;
 212                 }
 213
 214                 heartbeat = time;
 215                 wdt_enable();
 216                 /* Fall through */
 217
 218         case WDIOC_GETTIMEOUT:
 219                 ret = put_user(heartbeat, (int *)arg);
 220                 break;
 221
 222         case WDIOC_KEEPALIVE:
 223                 wdt_enable();
 224                 ret = 0;
 225                 break;
 226         }
 227         return ret;
 228 }
 229
 230 static int pnx4008_wdt_release(struct inode *inode, struct file *file)
 231 {
 232         if (!test_bit(WDT_OK_TO_CLOSE, &wdt_status))
 233                 printk(KERN_WARNING "WATCHDOG: Device closed unexpectdly\n");
 234
 235         wdt_disable();
 236         clear_bit(WDT_IN_USE, &wdt_status);
 237         clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
 238
 239         return 0;
 240 }
 241
 242 static struct file_operations pnx4008_wdt_fops = {
 243         .owner = THIS_MODULE,
 244         .llseek = no_llseek,
 245         .write = pnx4008_wdt_write,
 246         .ioctl = pnx4008_wdt_ioctl,
 247         .open = pnx4008_wdt_open,
 248         .release = pnx4008_wdt_release,
 249 };
 250
 251 static struct miscdevice pnx4008_wdt_miscdev = {
 252         .minor = WATCHDOG_MINOR,
 253         .name = "watchdog",
 254         .fops = &pnx4008_wdt_fops,
 255 };
 256
 257 static int pnx4008_wdt_probe(struct platform_device *pdev)
 258 {
 259         int ret = 0, size;
 260         struct resource *res;
 261
 262         spin_lock_init(&io_lock);
 263
 264         if (heartbeat < 1 || heartbeat > MAX_HEARTBEAT)
 265                 heartbeat = DEFAULT_HEARTBEAT;
 266
 267         printk(KERN_INFO MODULE_NAME
 268                 "PNX4008 Watchdog Timer: heartbeat %d sec\n", heartbeat);
 269
 270         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 271         if (res == NULL) {
 272                 printk(KERN_INFO MODULE_NAME
 273                         "failed to get memory region resouce\n");
 274                 return -ENOENT;
 275         }
 276
 277         size = res->end - res->start + 1;
 278         wdt_mem = request_mem_region(res->start, size, pdev->name);
 279
 280         if (wdt_mem == NULL) {
 281                 printk(KERN_INFO MODULE_NAME "failed to get memory region\n");
 282                 return -ENOENT;
 283         }
 284         wdt_base = (void __iomem *)IO_ADDRESS(res->start);
 285
 286         wdt_clk = clk_get(&pdev->dev, "wdt_ck");
 287         if (!wdt_clk) {
 288                 release_resource(wdt_mem);
 289                 kfree(wdt_mem);
 290                 goto out;
 291         } else
 292                 clk_set_rate(wdt_clk, 1);
 293
 294         ret = misc_register(&pnx4008_wdt_miscdev);
 295         if (ret < 0) {
 296                 printk(KERN_ERR MODULE_NAME "cannot register misc device\n");
 297                 release_resource(wdt_mem);
 298                 kfree(wdt_mem);
 299                 clk_set_rate(wdt_clk, 0);
 300         } else {
 301                 boot_status = (__raw_readl(WDTIM_RES(wdt_base)) & WDOG_RESET) ?
 302                     WDIOF_CARDRESET : 0;
 303                 wdt_disable();          /*disable for now */
 304                 set_bit(WDT_DEVICE_INITED, &wdt_status);
 305         }
 306
 307 out:
 308         return ret;
 309 }
 310
 311 static int pnx4008_wdt_remove(struct platform_device *pdev)
 312 {
 313         misc_deregister(&pnx4008_wdt_miscdev);
 314         if (wdt_clk) {
 315                 clk_set_rate(wdt_clk, 0);
 316                 clk_put(wdt_clk);
 317                 wdt_clk = NULL;
 318         }
 319         if (wdt_mem) {
 320                 release_resource(wdt_mem);
 321                 kfree(wdt_mem);
 322                 wdt_mem = NULL;
 323         }
 324         return 0;
 325 }
 326
 327 static struct platform_driver platform_wdt_driver = {
 328         .driver = {
 329                 .name = "watchdog",
 330         },
 331         .probe = pnx4008_wdt_probe,
 332         .remove = pnx4008_wdt_remove,
 333 };
 334
 335 static int __init pnx4008_wdt_init(void)
 336 {
 337         return platform_driver_register(&platform_wdt_driver);
 338 }
 339
 340 static void __exit pnx4008_wdt_exit(void)
 341 {
 342         return platform_driver_unregister(&platform_wdt_driver);
 343 }
 344
 345 module_init(pnx4008_wdt_init);
 346 module_exit(pnx4008_wdt_exit);
 347
 348 MODULE_AUTHOR("MontaVista Software, Inc. <source@mvista.com>");
 349 MODULE_DESCRIPTION("PNX4008 Watchdog Driver");
 350
 351 module_param(heartbeat, int, 0);
 352 MODULE_PARM_DESC(heartbeat,
 353                  "Watchdog heartbeat period in seconds from 1 to "
 354                  __MODULE_STRING(MAX_HEARTBEAT) ", default "
 355                  __MODULE_STRING(DEFAULT_HEARTBEAT));
 356
 357 module_param(nowayout, int, 0);
 358 MODULE_PARM_DESC(nowayout,
 359                  "Set to 1 to keep watchdog running after device release");
 360
 361 MODULE_LICENSE("GPL");
 362 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);