target/linux/gemini/files-4.4/drivers/watchdog/gemini_wdt.c

   1 /*
   2  *  Watchdog driver for Cortina Systems Gemini SoC
   3  *
   4  *  Copyright (C) 2009 Paulius Zaleckas <paulius.zaleckas@teltonika.lt>
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License version 2 as
   8  * published by the Free Software Foundation.
   9  */
  10
  11 #include <linux/kernel.h>
  12 #include <linux/init.h>
  13 #include <linux/module.h>
  14 #include <linux/io.h>
  15 #include <linux/fs.h>
  16 #include <linux/uaccess.h>
  17 #include <linux/miscdevice.h>
  18 #include <linux/platform_device.h>
  19 #include <linux/watchdog.h>
  20 #include <linux/slab.h>
  21
  22 #define GEMINI_WDCOUNTER        0x0
  23 #define GEMINI_WDLOAD           0x4
  24 #define GEMINI_WDRESTART        0x8
  25
  26 #define WDRESTART_MAGIC         0x5AB9
  27
  28 #define GEMINI_WDCR             0xC
  29
  30 #define WDCR_CLOCK_5MHZ         (1 << 4)
  31 #define WDCR_SYS_RST            (1 << 1)
  32 #define WDCR_ENABLE             (1 << 0)
  33
  34 #define WDT_CLOCK               5000000         /* 5 MHz */
  35 #define WDT_DEFAULT_TIMEOUT     13
  36 #define WDT_MAX_TIMEOUT         (0xFFFFFFFF / WDT_CLOCK)
  37
  38 /* status bits */
  39 #define WDT_ACTIVE              0
  40 #define WDT_OK_TO_CLOSE         1
  41
  42 static unsigned int timeout = WDT_DEFAULT_TIMEOUT;
  43 static int nowayout = WATCHDOG_NOWAYOUT;
  44
  45 static DEFINE_SPINLOCK(gemini_wdt_lock);
  46
  47 static struct platform_device *gemini_wdt_dev;
  48
  49 struct gemini_wdt_struct {
  50         struct resource         *res;
  51         struct device           *dev;
  52         void __iomem            *base;
  53         unsigned long           status;
  54 };
  55
  56 static struct watchdog_info gemini_wdt_info = {
  57         .identity       = "Gemini watchdog",
  58         .options        = WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING |
  59                           WDIOF_SETTIMEOUT,
  60 };
  61
  62 /* Disable the watchdog. */
  63 static void gemini_wdt_stop(struct gemini_wdt_struct *gemini_wdt)
  64 {
  65         spin_lock(&gemini_wdt_lock);
  66
  67         __raw_writel(0, gemini_wdt->base + GEMINI_WDCR);
  68
  69         clear_bit(WDT_ACTIVE, &gemini_wdt->status);
  70
  71         spin_unlock(&gemini_wdt_lock);
  72 }
  73
  74 /* Service the watchdog */
  75 static void gemini_wdt_service(struct gemini_wdt_struct *gemini_wdt)
  76 {
  77         __raw_writel(WDRESTART_MAGIC, gemini_wdt->base + GEMINI_WDRESTART);
  78 }
  79
  80 /* Enable and reset the watchdog. */
  81 static void gemini_wdt_start(struct gemini_wdt_struct *gemini_wdt)
  82 {
  83         spin_lock(&gemini_wdt_lock);
  84
  85         __raw_writel(timeout * WDT_CLOCK, gemini_wdt->base + GEMINI_WDLOAD);
  86
  87         gemini_wdt_service(gemini_wdt);
  88
  89         /* set clock before enabling */
  90         __raw_writel(WDCR_CLOCK_5MHZ | WDCR_SYS_RST,
  91                         gemini_wdt->base + GEMINI_WDCR);
  92
  93         __raw_writel(WDCR_CLOCK_5MHZ | WDCR_SYS_RST | WDCR_ENABLE,
  94                         gemini_wdt->base + GEMINI_WDCR);
  95
  96         set_bit(WDT_ACTIVE, &gemini_wdt->status);
  97
  98         spin_unlock(&gemini_wdt_lock);
  99 }
 100
 101 /* Watchdog device is opened, and watchdog starts running. */
 102 static int gemini_wdt_open(struct inode *inode, struct file *file)
 103 {
 104         struct gemini_wdt_struct *gemini_wdt = platform_get_drvdata(gemini_wdt_dev);
 105
 106         if (test_bit(WDT_ACTIVE, &gemini_wdt->status))
 107                 return -EBUSY;
 108
 109         file->private_data = gemini_wdt;
 110
 111         gemini_wdt_start(gemini_wdt);
 112
 113         return nonseekable_open(inode, file);
 114 }
 115
 116 /* Close the watchdog device. */
 117 static int gemini_wdt_close(struct inode *inode, struct file *file)
 118 {
 119         struct gemini_wdt_struct *gemini_wdt = file->private_data;
 120
 121         /* Disable the watchdog if possible */
 122         if (test_bit(WDT_OK_TO_CLOSE, &gemini_wdt->status))
 123                 gemini_wdt_stop(gemini_wdt);
 124         else
 125                 dev_warn(gemini_wdt->dev, "Device closed unexpectedly - timer will not stop\n");
 126
 127         return 0;
 128 }
 129
 130 /* Handle commands from user-space. */
 131 static long gemini_wdt_ioctl(struct file *file, unsigned int cmd,
 132                              unsigned long arg)
 133 {
 134         struct gemini_wdt_struct *gemini_wdt = file->private_data;
 135
 136         int value;
 137
 138         switch (cmd) {
 139         case WDIOC_KEEPALIVE:
 140                 gemini_wdt_service(gemini_wdt);
 141                 return 0;
 142
 143         case WDIOC_GETSUPPORT:
 144                 return copy_to_user((struct watchdog_info *)arg, &gemini_wdt_info,
 145                         sizeof(gemini_wdt_info)) ? -EFAULT : 0;
 146
 147         case WDIOC_SETTIMEOUT:
 148                 if (get_user(value, (int *)arg))
 149                         return -EFAULT;
 150
 151                 if ((value < 1) || (value > WDT_MAX_TIMEOUT))
 152                         return -EINVAL;
 153
 154                 timeout = value;
 155
 156                 /* restart wdt to use new timeout */
 157                 gemini_wdt_stop(gemini_wdt);
 158                 gemini_wdt_start(gemini_wdt);
 159
 160                 /* Fall through */
 161         case WDIOC_GETTIMEOUT:
 162                 return put_user(timeout, (int *)arg);
 163
 164         case WDIOC_GETTIMELEFT:
 165                 value = __raw_readl(gemini_wdt->base + GEMINI_WDCOUNTER);
 166                 return put_user(value / WDT_CLOCK, (int *)arg);
 167
 168         default:
 169                 return -ENOTTY;
 170         }
 171 }
 172
 173 /* Refresh the watchdog whenever device is written to. */
 174 static ssize_t gemini_wdt_write(struct file *file, const char *data,
 175                                                 size_t len, loff_t *ppos)
 176 {
 177         struct gemini_wdt_struct *gemini_wdt = file->private_data;
 178
 179         if (len) {
 180                 if (!nowayout) {
 181                         size_t i;
 182
 183                         clear_bit(WDT_OK_TO_CLOSE, &gemini_wdt->status);
 184                         for (i = 0; i != len; i++) {
 185                                 char c;
 186
 187                                 if (get_user(c, data + i))
 188                                         return -EFAULT;
 189                                 if (c == 'V')
 190                                         set_bit(WDT_OK_TO_CLOSE,
 191                                                 &gemini_wdt->status);
 192                         }
 193                 }
 194                 gemini_wdt_service(gemini_wdt);
 195         }
 196
 197         return len;
 198 }
 199
 200 static const struct file_operations gemini_wdt_fops = {
 201         .owner          = THIS_MODULE,
 202         .llseek         = no_llseek,
 203         .unlocked_ioctl = gemini_wdt_ioctl,
 204         .open           = gemini_wdt_open,
 205         .release        = gemini_wdt_close,
 206         .write          = gemini_wdt_write,
 207 };
 208
 209 static struct miscdevice gemini_wdt_miscdev = {
 210         .minor          = WATCHDOG_MINOR,
 211         .name           = "watchdog",
 212         .fops           = &gemini_wdt_fops,
 213 };
 214
 215 static void gemini_wdt_shutdown(struct platform_device *pdev)
 216 {
 217         struct gemini_wdt_struct *gemini_wdt = platform_get_drvdata(pdev);
 218
 219         gemini_wdt_stop(gemini_wdt);
 220 }
 221
 222 static int gemini_wdt_probe(struct platform_device *pdev)
 223 {
 224         int ret;
 225         int res_size;
 226         struct resource *res;
 227         void __iomem *base;
 228         struct gemini_wdt_struct *gemini_wdt;
 229         unsigned int reg;
 230
 231         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 232         if (!res) {
 233                 dev_err(&pdev->dev, "can't get device resources\n");
 234                 return -ENODEV;
 235         }
 236
 237         res_size = resource_size(res);
 238         if (!request_mem_region(res->start, res_size, res->name)) {
 239                 dev_err(&pdev->dev, "can't allocate %d bytes at %d address\n",
 240                         res_size, res->start);
 241                 return -ENOMEM;
 242         }
 243
 244         base = ioremap(res->start, res_size);
 245         if (!base) {
 246                 dev_err(&pdev->dev, "ioremap failed\n");
 247                 ret = -EIO;
 248                 goto fail0;
 249         }
 250
 251         gemini_wdt = kzalloc(sizeof(struct gemini_wdt_struct), GFP_KERNEL);
 252         if (!gemini_wdt) {
 253                 dev_err(&pdev->dev, "can't allocate interface\n");
 254                 ret = -ENOMEM;
 255                 goto fail1;
 256         }
 257
 258         /* Setup gemini_wdt driver structure */
 259         gemini_wdt->base = base;
 260         gemini_wdt->res = res;
 261
 262         /* Set up platform driver data */
 263         platform_set_drvdata(pdev, gemini_wdt);
 264         gemini_wdt_dev = pdev;
 265
 266         if (gemini_wdt_miscdev.parent) {
 267                 ret = -EBUSY;
 268                 goto fail2;
 269         }
 270
 271         gemini_wdt_miscdev.parent = &pdev->dev;
 272
 273         reg = __raw_readw(gemini_wdt->base + GEMINI_WDCR);
 274         if (reg & WDCR_ENABLE) {
 275                 /* Watchdog was enabled by the bootloader, disable it. */
 276                 reg &= ~(WDCR_ENABLE);
 277                 __raw_writel(reg, gemini_wdt->base + GEMINI_WDCR);
 278         }
 279
 280         ret = misc_register(&gemini_wdt_miscdev);
 281         if (ret)
 282                 goto fail2;
 283
 284         return 0;
 285
 286 fail2:
 287         platform_set_drvdata(pdev, NULL);
 288         kfree(gemini_wdt);
 289 fail1:
 290         iounmap(base);
 291 fail0:
 292         release_mem_region(res->start, res_size);
 293
 294         return ret;
 295 }
 296
 297 static int gemini_wdt_remove(struct platform_device *pdev)
 298 {
 299         struct gemini_wdt_struct *gemini_wdt = platform_get_drvdata(pdev);
 300
 301         platform_set_drvdata(pdev, NULL);
 302         misc_deregister(&gemini_wdt_miscdev);
 303         gemini_wdt_dev = NULL;
 304         iounmap(gemini_wdt->base);
 305         release_mem_region(gemini_wdt->res->start, resource_size(gemini_wdt->res));
 306
 307         kfree(gemini_wdt);
 308
 309         return 0;
 310 }
 311
 312 #ifdef CONFIG_PM
 313 static int gemini_wdt_suspend(struct platform_device *pdev, pm_message_t message)
 314 {
 315         struct gemini_wdt_struct *gemini_wdt = platform_get_drvdata(pdev);
 316         unsigned int reg;
 317
 318         reg = __raw_readw(gemini_wdt->base + GEMINI_WDCR);
 319         reg &= ~(WDCR_WDENABLE);
 320         __raw_writel(reg, gemini_wdt->base + GEMINI_WDCR);
 321
 322         return 0;
 323 }
 324
 325 static int gemini_wdt_resume(struct platform_device *pdev)
 326 {
 327         struct gemini_wdt_struct *gemini_wdt = platform_get_drvdata(pdev);
 328         unsigned int reg;
 329
 330         if (gemini_wdt->status) {
 331                 reg = __raw_readw(gemini_wdt->base + GEMINI_WDCR);
 332                 reg |= WDCR_WDENABLE;
 333                 __raw_writel(reg, gemini_wdt->base + GEMINI_WDCR);
 334         }
 335
 336         return 0;
 337 }
 338 #else
 339 #define gemini_wdt_suspend      NULL
 340 #define gemini_wdt_resume       NULL
 341 #endif
 342
 343 static struct platform_driver gemini_wdt_driver = {
 344         .probe          = gemini_wdt_probe,
 345         .remove         = gemini_wdt_remove,
 346         .shutdown       = gemini_wdt_shutdown,
 347         .suspend        = gemini_wdt_suspend,
 348         .resume         = gemini_wdt_resume,
 349         .driver         = {
 350                 .name   = "gemini-wdt",
 351                 .owner  = THIS_MODULE,
 352         },
 353 };
 354
 355 static int __init gemini_wdt_init(void)
 356 {
 357         return platform_driver_probe(&gemini_wdt_driver, gemini_wdt_probe);
 358 }
 359
 360 static void __exit gemini_wdt_exit(void)
 361 {
 362         platform_driver_unregister(&gemini_wdt_driver);
 363 }
 364
 365 module_init(gemini_wdt_init);
 366 module_exit(gemini_wdt_exit);
 367
 368 module_param(timeout, uint, 0);
 369 MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds");
 370
 371 module_param(nowayout, int, 0);
 372 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started");
 373
 374 MODULE_AUTHOR("Paulius Zaleckas");
 375 MODULE_DESCRIPTION("Watchdog driver for Gemini");
 376 MODULE_LICENSE("GPL");
 377 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
 378 MODULE_ALIAS("platform:gemini-wdt");