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