drivers/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 #include <linux/uaccess.h>
  32 #include <linux/io.h>
  33 #include <linux/slab.h>
  34 #include <mach/hardware.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 DEFINE_SPINLOCK(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         /* stop counter, initiate counter reset */
 101         __raw_writel(RESET_COUNT, WDTIM_CTRL(wdt_base));
 102         /*wait for reset to complete. 100% guarantee event */
 103         while (__raw_readl(WDTIM_COUNTER(wdt_base)))
 104                 cpu_relax();
 105         /* internal and external reset, stop after that */
 106         __raw_writel(M_RES2 | STOP_COUNT0 | RESET_COUNT0,
 107                 WDTIM_MCTRL(wdt_base));
 108         /* configure match output */
 109         __raw_writel(MATCH_OUTPUT_HIGH, WDTIM_EMR(wdt_base));
 110         /* clear interrupt, just in case */
 111         __raw_writel(MATCH_INT, WDTIM_INT(wdt_base));
 112         /* the longest pulse period 65541/(13*10^6) seconds ~ 5 ms. */
 113         __raw_writel(0xFFFF, WDTIM_PULSE(wdt_base));
 114         __raw_writel(heartbeat * WDOG_COUNTER_RATE, WDTIM_MATCH0(wdt_base));
 115         /*enable counter, stop when debugger active */
 116         __raw_writel(COUNT_ENAB | DEBUG_EN, WDTIM_CTRL(wdt_base));
 117
 118         spin_unlock(&io_lock);
 119 }
 120
 121 static void wdt_disable(void)
 122 {
 123         spin_lock(&io_lock);
 124
 125         __raw_writel(0, WDTIM_CTRL(wdt_base));  /*stop counter */
 126
 127         spin_unlock(&io_lock);
 128 }
 129
 130 static int pnx4008_wdt_open(struct inode *inode, struct file *file)
 131 {
 132         int ret;
 133
 134         if (test_and_set_bit(WDT_IN_USE, &wdt_status))
 135                 return -EBUSY;
 136
 137         clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
 138
 139         ret = clk_enable(wdt_clk);
 140         if (ret) {
 141                 clear_bit(WDT_IN_USE, &wdt_status);
 142                 return ret;
 143         }
 144
 145         wdt_enable();
 146
 147         return nonseekable_open(inode, file);
 148 }
 149
 150 static ssize_t pnx4008_wdt_write(struct file *file, const char *data,
 151                                         size_t len, loff_t *ppos)
 152 {
 153         if (len) {
 154                 if (!nowayout) {
 155                         size_t i;
 156
 157                         clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
 158
 159                         for (i = 0; i != len; i++) {
 160                                 char c;
 161
 162                                 if (get_user(c, data + i))
 163                                         return -EFAULT;
 164                                 if (c == 'V')
 165                                         set_bit(WDT_OK_TO_CLOSE, &wdt_status);
 166                         }
 167                 }
 168                 wdt_enable();
 169         }
 170
 171         return len;
 172 }
 173
 174 static const struct watchdog_info ident = {
 175         .options = WDIOF_CARDRESET | WDIOF_MAGICCLOSE |
 176             WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
 177         .identity = "PNX4008 Watchdog",
 178 };
 179
 180 static long pnx4008_wdt_ioctl(struct file *file, unsigned int cmd,
 181                                 unsigned long arg)
 182 {
 183         int ret = -ENOTTY;
 184         int time;
 185
 186         switch (cmd) {
 187         case WDIOC_GETSUPPORT:
 188                 ret = copy_to_user((struct watchdog_info *)arg, &ident,
 189                                    sizeof(ident)) ? -EFAULT : 0;
 190                 break;
 191
 192         case WDIOC_GETSTATUS:
 193                 ret = put_user(0, (int *)arg);
 194                 break;
 195
 196         case WDIOC_GETBOOTSTATUS:
 197                 ret = put_user(boot_status, (int *)arg);
 198                 break;
 199
 200         case WDIOC_KEEPALIVE:
 201                 wdt_enable();
 202                 ret = 0;
 203                 break;
 204
 205         case WDIOC_SETTIMEOUT:
 206                 ret = get_user(time, (int *)arg);
 207                 if (ret)
 208                         break;
 209
 210                 if (time <= 0 || time > MAX_HEARTBEAT) {
 211                         ret = -EINVAL;
 212                         break;
 213                 }
 214
 215                 heartbeat = time;
 216                 wdt_enable();
 217                 /* Fall through */
 218
 219         case WDIOC_GETTIMEOUT:
 220                 ret = put_user(heartbeat, (int *)arg);
 221                 break;
 222         }
 223         return ret;
 224 }
 225
 226 static int pnx4008_wdt_release(struct inode *inode, struct file *file)
 227 {
 228         if (!test_bit(WDT_OK_TO_CLOSE, &wdt_status))
 229                 printk(KERN_WARNING "WATCHDOG: Device closed unexpectedly\n");
 230
 231         wdt_disable();
 232         clk_disable(wdt_clk);
 233         clear_bit(WDT_IN_USE, &wdt_status);
 234         clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
 235
 236         return 0;
 237 }
 238
 239 static const struct file_operations pnx4008_wdt_fops = {
 240         .owner = THIS_MODULE,
 241         .llseek = no_llseek,
 242         .write = pnx4008_wdt_write,
 243         .unlocked_ioctl = pnx4008_wdt_ioctl,
 244         .open = pnx4008_wdt_open,
 245         .release = pnx4008_wdt_release,
 246 };
 247
 248 static struct miscdevice pnx4008_wdt_miscdev = {
 249         .minor = WATCHDOG_MINOR,
 250         .name = "watchdog",
 251         .fops = &pnx4008_wdt_fops,
 252 };
 253
 254 static int __devinit pnx4008_wdt_probe(struct platform_device *pdev)
 255 {
 256         int ret = 0, size;
 257
 258         if (heartbeat < 1 || heartbeat > MAX_HEARTBEAT)
 259                 heartbeat = DEFAULT_HEARTBEAT;
 260
 261         printk(KERN_INFO MODULE_NAME
 262                 "PNX4008 Watchdog Timer: heartbeat %d sec\n", heartbeat);
 263
 264         wdt_mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 265         if (wdt_mem == NULL) {
 266                 printk(KERN_INFO MODULE_NAME
 267                         "failed to get memory region resource\n");
 268                 return -ENOENT;
 269         }
 270
 271         size = resource_size(wdt_mem);
 272
 273         if (!request_mem_region(wdt_mem->start, size, pdev->name)) {
 274                 printk(KERN_INFO MODULE_NAME "failed to get memory region\n");
 275                 return -ENOENT;
 276         }
 277         wdt_base = (void __iomem *)IO_ADDRESS(wdt_mem->start);
 278
 279         wdt_clk = clk_get(&pdev->dev, NULL);
 280         if (IS_ERR(wdt_clk)) {
 281                 ret = PTR_ERR(wdt_clk);
 282                 release_mem_region(wdt_mem->start, size);
 283                 wdt_mem = NULL;
 284                 goto out;
 285         }
 286
 287         ret = clk_enable(wdt_clk);
 288         if (ret) {
 289                 release_mem_region(wdt_mem->start, size);
 290                 wdt_mem = NULL;
 291                 clk_put(wdt_clk);
 292                 goto out;
 293         }
 294
 295         ret = misc_register(&pnx4008_wdt_miscdev);
 296         if (ret < 0) {
 297                 printk(KERN_ERR MODULE_NAME "cannot register misc device\n");
 298                 release_mem_region(wdt_mem->start, size);
 299                 wdt_mem = NULL;
 300                 clk_disable(wdt_clk);
 301                 clk_put(wdt_clk);
 302         } else {
 303                 boot_status = (__raw_readl(WDTIM_RES(wdt_base)) & WDOG_RESET) ?
 304                     WDIOF_CARDRESET : 0;
 305                 wdt_disable();          /*disable for now */
 306                 clk_disable(wdt_clk);
 307                 set_bit(WDT_DEVICE_INITED, &wdt_status);
 308         }
 309
 310 out:
 311         return ret;
 312 }
 313
 314 static int __devexit pnx4008_wdt_remove(struct platform_device *pdev)
 315 {
 316         misc_deregister(&pnx4008_wdt_miscdev);
 317
 318         clk_disable(wdt_clk);
 319         clk_put(wdt_clk);
 320
 321         if (wdt_mem) {
 322                 release_mem_region(wdt_mem->start, resource_size(wdt_mem));
 323                 wdt_mem = NULL;
 324         }
 325         return 0;
 326 }
 327
 328 static struct platform_driver platform_wdt_driver = {
 329         .driver = {
 330                 .name = "pnx4008-watchdog",
 331                 .owner  = THIS_MODULE,
 332         },
 333         .probe = pnx4008_wdt_probe,
 334         .remove = __devexit_p(pnx4008_wdt_remove),
 335 };
 336
 337 module_platform_driver(platform_wdt_driver);
 338
 339 MODULE_AUTHOR("MontaVista Software, Inc. <source@mvista.com>");
 340 MODULE_DESCRIPTION("PNX4008 Watchdog Driver");
 341
 342 module_param(heartbeat, int, 0);
 343 MODULE_PARM_DESC(heartbeat,
 344                  "Watchdog heartbeat period in seconds from 1 to "
 345                  __MODULE_STRING(MAX_HEARTBEAT) ", default "
 346                  __MODULE_STRING(DEFAULT_HEARTBEAT));
 347
 348 module_param(nowayout, int, 0);
 349 MODULE_PARM_DESC(nowayout,
 350                  "Set to 1 to keep watchdog running after device release");
 351
 352 MODULE_LICENSE("GPL");
 353 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
 354 MODULE_ALIAS("platform:pnx4008-watchdog");