target/linux/lantiq/patches-2.6.32/0013-MIPS-Lantiq-Add-watchdog-support.patch

   1 From 3466449c8f455da0cb646231602e6af16190f592 Mon Sep 17 00:00:00 2001
   2 From: John Crispin <blogic@openwrt.org>
   3 Date: Thu, 5 May 2011 23:00:23 +0200
   4 Subject: [PATCH 13/13] MIPS: Lantiq: Add watchdog support
   5
   6 This patch adds the driver for the watchdog found inside the Lantiq SoC family.
   7
   8 Signed-off-by: John Crispin <blogic@openwrt.org>
   9 Signed-off-by: Ralph Hempel <ralph.hempel@lantiq.com>
  10 Cc: Wim Van Sebroeck <wim@iguana.be>
  11 Cc: linux-mips@linux-mips.org
  12 Cc: linux-watchdog@vger.kernel.org
  13 Patchwork: https://patchwork.linux-mips.org/patch/2327/
  14 Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
  15 ---
  16  drivers/watchdog/Kconfig      |    6 +
  17  drivers/watchdog/Makefile     |    1 +
  18  drivers/watchdog/lantiq_wdt.c |  261 +++++++++++++++++++++++++++++++++++++++++
  19  3 files changed, 268 insertions(+), 0 deletions(-)
  20  create mode 100644 drivers/watchdog/lantiq_wdt.c
  21
  22 --- a/drivers/watchdog/Kconfig
  23 +++ b/drivers/watchdog/Kconfig
  24 @@ -850,6 +850,12 @@
  25         help
  26           Hardware driver for the built-in watchdog timer on TXx9 MIPS SoCs.
  27
  28 +config LANTIQ_WDT
  29 +       tristate "Lantiq SoC watchdog"
  30 +       depends on LANTIQ
  31 +       help
  32 +         Hardware driver for the Lantiq SoC Watchdog Timer.
  33 +
  34  # PARISC Architecture
  35
  36  # POWERPC Architecture
  37 --- a/drivers/watchdog/Makefile
  38 +++ b/drivers/watchdog/Makefile
  39 @@ -113,6 +113,7 @@
  40  obj-$(CONFIG_SIBYTE_WDOG) += sb_wdog.o
  41  obj-$(CONFIG_AR7_WDT) += ar7_wdt.o
  42  obj-$(CONFIG_TXX9_WDT) += txx9wdt.o
  43 +obj-$(CONFIG_LANTIQ_WDT) += lantiq_wdt.o
  44
  45  # PARISC Architecture
  46
  47 --- /dev/null
  48 +++ b/drivers/watchdog/lantiq_wdt.c
  49 @@ -0,0 +1,261 @@
  50 +/*
  51 + *  This program is free software; you can redistribute it and/or modify it
  52 + *  under the terms of the GNU General Public License version 2 as published
  53 + *  by the Free Software Foundation.
  54 + *
  55 + *  Copyright (C) 2010 John Crispin <blogic@openwrt.org>
  56 + *  Based on EP93xx wdt driver
  57 + */
  58 +
  59 +#include <linux/module.h>
  60 +#include <linux/fs.h>
  61 +#include <linux/miscdevice.h>
  62 +#include <linux/watchdog.h>
  63 +#include <linux/platform_device.h>
  64 +#include <linux/uaccess.h>
  65 +#include <linux/clk.h>
  66 +#include <linux/io.h>
  67 +
  68 +#include <lantiq.h>
  69 +
  70 +/* Section 3.4 of the datasheet
  71 + * The password sequence protects the WDT control register from unintended
  72 + * write actions, which might cause malfunction of the WDT.
  73 + *
  74 + * essentially the following two magic passwords need to be written to allow
  75 + * IO access to the WDT core
  76 + */
  77 +#define LTQ_WDT_PW1            0x00BE0000
  78 +#define LTQ_WDT_PW2            0x00DC0000
  79 +
  80 +#define LTQ_WDT_CR             0x0     /* watchdog control register */
  81 +#define LTQ_WDT_SR             0x8     /* watchdog status register */
  82 +
  83 +#define LTQ_WDT_SR_EN          (0x1 << 31)     /* enable bit */
  84 +#define LTQ_WDT_SR_PWD         (0x3 << 26)     /* turn on power */
  85 +#define LTQ_WDT_SR_CLKDIV      (0x3 << 24)     /* turn on clock and set */
  86 +                                               /* divider to 0x40000 */
  87 +#define LTQ_WDT_DIVIDER                0x40000
  88 +#define LTQ_MAX_TIMEOUT                ((1 << 16) - 1) /* the reload field is 16 bit */
  89 +
  90 +static int nowayout = WATCHDOG_NOWAYOUT;
  91 +
  92 +static void __iomem *ltq_wdt_membase;
  93 +static unsigned long ltq_io_region_clk_rate;
  94 +
  95 +static unsigned long ltq_wdt_bootstatus;
  96 +static unsigned long ltq_wdt_in_use;
  97 +static int ltq_wdt_timeout = 30;
  98 +static int ltq_wdt_ok_to_close;
  99 +
 100 +static void
 101 +ltq_wdt_enable(void)
 102 +{
 103 +       ltq_wdt_timeout = ltq_wdt_timeout *
 104 +                       (ltq_io_region_clk_rate / LTQ_WDT_DIVIDER) + 0x1000;
 105 +       if (ltq_wdt_timeout > LTQ_MAX_TIMEOUT)
 106 +               ltq_wdt_timeout = LTQ_MAX_TIMEOUT;
 107 +
 108 +       /* write the first password magic */
 109 +       ltq_w32(LTQ_WDT_PW1, ltq_wdt_membase + LTQ_WDT_CR);
 110 +       /* write the second magic plus the configuration and new timeout */
 111 +       ltq_w32(LTQ_WDT_SR_EN | LTQ_WDT_SR_PWD | LTQ_WDT_SR_CLKDIV |
 112 +               LTQ_WDT_PW2 | ltq_wdt_timeout, ltq_wdt_membase + LTQ_WDT_CR);
 113 +}
 114 +
 115 +static void
 116 +ltq_wdt_disable(void)
 117 +{
 118 +       /* write the first password magic */
 119 +       ltq_w32(LTQ_WDT_PW1, ltq_wdt_membase + LTQ_WDT_CR);
 120 +       /* write the second password magic with no config
 121 +        * this turns the watchdog off
 122 +        */
 123 +       ltq_w32(LTQ_WDT_PW2, ltq_wdt_membase + LTQ_WDT_CR);
 124 +}
 125 +
 126 +static ssize_t
 127 +ltq_wdt_write(struct file *file, const char __user *data,
 128 +               size_t len, loff_t *ppos)
 129 +{
 130 +       if (len) {
 131 +               if (!nowayout) {
 132 +                       size_t i;
 133 +
 134 +                       ltq_wdt_ok_to_close = 0;
 135 +                       for (i = 0; i != len; i++) {
 136 +                               char c;
 137 +
 138 +                               if (get_user(c, data + i))
 139 +                                       return -EFAULT;
 140 +                               if (c == 'V')
 141 +                                       ltq_wdt_ok_to_close = 1;
 142 +                               else
 143 +                                       ltq_wdt_ok_to_close = 0;
 144 +                       }
 145 +               }
 146 +               ltq_wdt_enable();
 147 +       }
 148 +
 149 +       return len;
 150 +}
 151 +
 152 +static struct watchdog_info ident = {
 153 +       .options = WDIOF_MAGICCLOSE | WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING |
 154 +                       WDIOF_CARDRESET,
 155 +       .identity = "ltq_wdt",
 156 +};
 157 +
 158 +static long
 159 +ltq_wdt_ioctl(struct file *file,
 160 +               unsigned int cmd, unsigned long arg)
 161 +{
 162 +       int ret = -ENOTTY;
 163 +
 164 +       switch (cmd) {
 165 +       case WDIOC_GETSUPPORT:
 166 +               ret = copy_to_user((struct watchdog_info __user *)arg, &ident,
 167 +                               sizeof(ident)) ? -EFAULT : 0;
 168 +               break;
 169 +
 170 +       case WDIOC_GETBOOTSTATUS:
 171 +               ret = put_user(ltq_wdt_bootstatus, (int __user *)arg);
 172 +               break;
 173 +
 174 +       case WDIOC_GETSTATUS:
 175 +               ret = put_user(0, (int __user *)arg);
 176 +               break;
 177 +
 178 +       case WDIOC_SETTIMEOUT:
 179 +               ret = get_user(ltq_wdt_timeout, (int __user *)arg);
 180 +               if (!ret)
 181 +                       ltq_wdt_enable();
 182 +               /* intentional drop through */
 183 +       case WDIOC_GETTIMEOUT:
 184 +               ret = put_user(ltq_wdt_timeout, (int __user *)arg);
 185 +               break;
 186 +
 187 +       case WDIOC_KEEPALIVE:
 188 +               ltq_wdt_enable();
 189 +               ret = 0;
 190 +               break;
 191 +       }
 192 +       return ret;
 193 +}
 194 +
 195 +static int
 196 +ltq_wdt_open(struct inode *inode, struct file *file)
 197 +{
 198 +       if (test_and_set_bit(0, &ltq_wdt_in_use))
 199 +               return -EBUSY;
 200 +       ltq_wdt_in_use = 1;
 201 +       ltq_wdt_enable();
 202 +
 203 +       return nonseekable_open(inode, file);
 204 +}
 205 +
 206 +static int
 207 +ltq_wdt_release(struct inode *inode, struct file *file)
 208 +{
 209 +       if (ltq_wdt_ok_to_close)
 210 +               ltq_wdt_disable();
 211 +       else
 212 +               pr_err("ltq_wdt: watchdog closed without warning\n");
 213 +       ltq_wdt_ok_to_close = 0;
 214 +       clear_bit(0, &ltq_wdt_in_use);
 215 +
 216 +       return 0;
 217 +}
 218 +
 219 +static const struct file_operations ltq_wdt_fops = {
 220 +       .owner          = THIS_MODULE,
 221 +       .write          = ltq_wdt_write,
 222 +       .unlocked_ioctl = ltq_wdt_ioctl,
 223 +       .open           = ltq_wdt_open,
 224 +       .release        = ltq_wdt_release,
 225 +       .llseek         = no_llseek,
 226 +};
 227 +
 228 +static struct miscdevice ltq_wdt_miscdev = {
 229 +       .minor  = WATCHDOG_MINOR,
 230 +       .name   = "watchdog",
 231 +       .fops   = &ltq_wdt_fops,
 232 +};
 233 +
 234 +static int __init
 235 +ltq_wdt_probe(struct platform_device *pdev)
 236 +{
 237 +       struct resource *res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 238 +       struct clk *clk;
 239 +
 240 +       if (!res) {
 241 +               dev_err(&pdev->dev, "cannot obtain I/O memory region");
 242 +               return -ENOENT;
 243 +       }
 244 +       res = devm_request_mem_region(&pdev->dev, res->start,
 245 +               resource_size(res), dev_name(&pdev->dev));
 246 +       if (!res) {
 247 +               dev_err(&pdev->dev, "cannot request I/O memory region");
 248 +               return -EBUSY;
 249 +       }
 250 +       ltq_wdt_membase = devm_ioremap_nocache(&pdev->dev, res->start,
 251 +               resource_size(res));
 252 +       if (!ltq_wdt_membase) {
 253 +               dev_err(&pdev->dev, "cannot remap I/O memory region\n");
 254 +               return -ENOMEM;
 255 +       }
 256 +
 257 +       /* we do not need to enable the clock as it is always running */
 258 +       clk = clk_get(&pdev->dev, "io");
 259 +       WARN_ON(!clk);
 260 +       ltq_io_region_clk_rate = clk_get_rate(clk);
 261 +       clk_put(clk);
 262 +
 263 +       if (ltq_reset_cause() == LTQ_RST_CAUSE_WDTRST)
 264 +               ltq_wdt_bootstatus = WDIOF_CARDRESET;
 265 +
 266 +       return misc_register(&ltq_wdt_miscdev);
 267 +}
 268 +
 269 +static int __devexit
 270 +ltq_wdt_remove(struct platform_device *pdev)
 271 +{
 272 +       misc_deregister(&ltq_wdt_miscdev);
 273 +
 274 +       if (ltq_wdt_membase)
 275 +               iounmap(ltq_wdt_membase);
 276 +
 277 +       return 0;
 278 +}
 279 +
 280 +
 281 +static struct platform_driver ltq_wdt_driver = {
 282 +       .remove = __devexit_p(ltq_wdt_remove),
 283 +       .driver = {
 284 +               .name = "ltq_wdt",
 285 +               .owner = THIS_MODULE,
 286 +       },
 287 +};
 288 +
 289 +static int __init
 290 +init_ltq_wdt(void)
 291 +{
 292 +       return platform_driver_probe(&ltq_wdt_driver, ltq_wdt_probe);
 293 +}
 294 +
 295 +static void __exit
 296 +exit_ltq_wdt(void)
 297 +{
 298 +       return platform_driver_unregister(&ltq_wdt_driver);
 299 +}
 300 +
 301 +module_init(init_ltq_wdt);
 302 +module_exit(exit_ltq_wdt);
 303 +
 304 +module_param(nowayout, int, 0);
 305 +MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started");
 306 +
 307 +MODULE_AUTHOR("John Crispin <blogic@openwrt.org>");
 308 +MODULE_DESCRIPTION("Lantiq SoC Watchdog");
 309 +MODULE_LICENSE("GPL");
 310 +MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);