drivers/watchdog/orion_wdt.c

   1 /*
   2  * drivers/watchdog/orion_wdt.c
   3  *
   4  * Watchdog driver for Orion/Kirkwood processors
   5  *
   6  * Author: Sylver Bruneau <sylver.bruneau@googlemail.com>
   7  *
   8  * This file is licensed under  the terms of the GNU General Public
   9  * License version 2. This program is licensed "as is" without any
  10  * warranty of any kind, whether express or implied.
  11  */
  12
  13 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  14
  15 #include <linux/module.h>
  16 #include <linux/moduleparam.h>
  17 #include <linux/types.h>
  18 #include <linux/kernel.h>
  19 #include <linux/platform_device.h>
  20 #include <linux/watchdog.h>
  21 #include <linux/interrupt.h>
  22 #include <linux/io.h>
  23 #include <linux/clk.h>
  24 #include <linux/err.h>
  25 #include <linux/of.h>
  26 #include <linux/of_device.h>
  27
  28 /* RSTOUT mask register physical address for Orion5x, Kirkwood and Dove */
  29 #define ORION_RSTOUT_MASK_OFFSET        0x20108
  30
  31 /* Internal registers can be configured at any 1 MiB aligned address */
  32 #define INTERNAL_REGS_MASK              ~(SZ_1M - 1)
  33
  34 /*
  35  * Watchdog timer block registers.
  36  */
  37 #define TIMER_CTRL              0x0000
  38 #define TIMER_A370_STATUS       0x04
  39
  40 #define WDT_MAX_CYCLE_COUNT     0xffffffff
  41
  42 #define WDT_A370_RATIO_MASK(v)  ((v) << 16)
  43 #define WDT_A370_RATIO_SHIFT    5
  44 #define WDT_A370_RATIO          (1 << WDT_A370_RATIO_SHIFT)
  45
  46 #define WDT_AXP_FIXED_ENABLE_BIT BIT(10)
  47 #define WDT_A370_EXPIRED        BIT(31)
  48
  49 static bool nowayout = WATCHDOG_NOWAYOUT;
  50 static int heartbeat = -1;              /* module parameter (seconds) */
  51
  52 struct orion_watchdog;
  53
  54 struct orion_watchdog_data {
  55         int wdt_counter_offset;
  56         int wdt_enable_bit;
  57         int rstout_enable_bit;
  58         int (*clock_init)(struct platform_device *,
  59                           struct orion_watchdog *);
  60         int (*start)(struct watchdog_device *);
  61 };
  62
  63 struct orion_watchdog {
  64         struct watchdog_device wdt;
  65         void __iomem *reg;
  66         void __iomem *rstout;
  67         unsigned long clk_rate;
  68         struct clk *clk;
  69         const struct orion_watchdog_data *data;
  70 };
  71
  72 static int orion_wdt_clock_init(struct platform_device *pdev,
  73                                 struct orion_watchdog *dev)
  74 {
  75         int ret;
  76
  77         dev->clk = clk_get(&pdev->dev, NULL);
  78         if (IS_ERR(dev->clk))
  79                 return PTR_ERR(dev->clk);
  80         ret = clk_prepare_enable(dev->clk);
  81         if (ret) {
  82                 clk_put(dev->clk);
  83                 return ret;
  84         }
  85
  86         dev->clk_rate = clk_get_rate(dev->clk);
  87         return 0;
  88 }
  89
  90 static int armada370_wdt_clock_init(struct platform_device *pdev,
  91                                     struct orion_watchdog *dev)
  92 {
  93         int ret;
  94
  95         dev->clk = clk_get(&pdev->dev, NULL);
  96         if (IS_ERR(dev->clk))
  97                 return PTR_ERR(dev->clk);
  98         ret = clk_prepare_enable(dev->clk);
  99         if (ret) {
 100                 clk_put(dev->clk);
 101                 return ret;
 102         }
 103
 104         /* Setup watchdog input clock */
 105         atomic_io_modify(dev->reg + TIMER_CTRL,
 106                         WDT_A370_RATIO_MASK(WDT_A370_RATIO_SHIFT),
 107                         WDT_A370_RATIO_MASK(WDT_A370_RATIO_SHIFT));
 108
 109         dev->clk_rate = clk_get_rate(dev->clk) / WDT_A370_RATIO;
 110         return 0;
 111 }
 112
 113 static int armadaxp_wdt_clock_init(struct platform_device *pdev,
 114                                    struct orion_watchdog *dev)
 115 {
 116         int ret;
 117
 118         dev->clk = of_clk_get_by_name(pdev->dev.of_node, "fixed");
 119         if (IS_ERR(dev->clk))
 120                 return PTR_ERR(dev->clk);
 121         ret = clk_prepare_enable(dev->clk);
 122         if (ret) {
 123                 clk_put(dev->clk);
 124                 return ret;
 125         }
 126
 127         /* Enable the fixed watchdog clock input */
 128         atomic_io_modify(dev->reg + TIMER_CTRL,
 129                          WDT_AXP_FIXED_ENABLE_BIT,
 130                          WDT_AXP_FIXED_ENABLE_BIT);
 131
 132         dev->clk_rate = clk_get_rate(dev->clk);
 133         return 0;
 134 }
 135
 136 static int orion_wdt_ping(struct watchdog_device *wdt_dev)
 137 {
 138         struct orion_watchdog *dev = watchdog_get_drvdata(wdt_dev);
 139         /* Reload watchdog duration */
 140         writel(dev->clk_rate * wdt_dev->timeout,
 141                dev->reg + dev->data->wdt_counter_offset);
 142         return 0;
 143 }
 144
 145 static int armada370_start(struct watchdog_device *wdt_dev)
 146 {
 147         struct orion_watchdog *dev = watchdog_get_drvdata(wdt_dev);
 148
 149         /* Set watchdog duration */
 150         writel(dev->clk_rate * wdt_dev->timeout,
 151                dev->reg + dev->data->wdt_counter_offset);
 152
 153         /* Clear the watchdog expiration bit */
 154         atomic_io_modify(dev->reg + TIMER_A370_STATUS, WDT_A370_EXPIRED, 0);
 155
 156         /* Enable watchdog timer */
 157         atomic_io_modify(dev->reg + TIMER_CTRL, dev->data->wdt_enable_bit,
 158                                                 dev->data->wdt_enable_bit);
 159
 160         atomic_io_modify(dev->rstout, dev->data->rstout_enable_bit,
 161                                       dev->data->rstout_enable_bit);
 162         return 0;
 163 }
 164
 165 static int orion_start(struct watchdog_device *wdt_dev)
 166 {
 167         struct orion_watchdog *dev = watchdog_get_drvdata(wdt_dev);
 168
 169         /* Set watchdog duration */
 170         writel(dev->clk_rate * wdt_dev->timeout,
 171                dev->reg + dev->data->wdt_counter_offset);
 172
 173         /* Enable watchdog timer */
 174         atomic_io_modify(dev->reg + TIMER_CTRL, dev->data->wdt_enable_bit,
 175                                                 dev->data->wdt_enable_bit);
 176
 177         /* Enable reset on watchdog */
 178         atomic_io_modify(dev->rstout, dev->data->rstout_enable_bit,
 179                                       dev->data->rstout_enable_bit);
 180
 181         return 0;
 182 }
 183
 184 static int orion_wdt_start(struct watchdog_device *wdt_dev)
 185 {
 186         struct orion_watchdog *dev = watchdog_get_drvdata(wdt_dev);
 187
 188         /* There are some per-SoC quirks to handle */
 189         return dev->data->start(wdt_dev);
 190 }
 191
 192 static int orion_wdt_stop(struct watchdog_device *wdt_dev)
 193 {
 194         struct orion_watchdog *dev = watchdog_get_drvdata(wdt_dev);
 195
 196         /* Disable reset on watchdog */
 197         atomic_io_modify(dev->rstout, dev->data->rstout_enable_bit, 0);
 198
 199         /* Disable watchdog timer */
 200         atomic_io_modify(dev->reg + TIMER_CTRL, dev->data->wdt_enable_bit, 0);
 201
 202         return 0;
 203 }
 204
 205 static int orion_wdt_enabled(struct orion_watchdog *dev)
 206 {
 207         bool enabled, running;
 208
 209         enabled = readl(dev->rstout) & dev->data->rstout_enable_bit;
 210         running = readl(dev->reg + TIMER_CTRL) & dev->data->wdt_enable_bit;
 211
 212         return enabled && running;
 213 }
 214
 215 static unsigned int orion_wdt_get_timeleft(struct watchdog_device *wdt_dev)
 216 {
 217         struct orion_watchdog *dev = watchdog_get_drvdata(wdt_dev);
 218         return readl(dev->reg + dev->data->wdt_counter_offset) / dev->clk_rate;
 219 }
 220
 221 static int orion_wdt_set_timeout(struct watchdog_device *wdt_dev,
 222                                  unsigned int timeout)
 223 {
 224         wdt_dev->timeout = timeout;
 225         return 0;
 226 }
 227
 228 static const struct watchdog_info orion_wdt_info = {
 229         .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
 230         .identity = "Orion Watchdog",
 231 };
 232
 233 static const struct watchdog_ops orion_wdt_ops = {
 234         .owner = THIS_MODULE,
 235         .start = orion_wdt_start,
 236         .stop = orion_wdt_stop,
 237         .ping = orion_wdt_ping,
 238         .set_timeout = orion_wdt_set_timeout,
 239         .get_timeleft = orion_wdt_get_timeleft,
 240 };
 241
 242 static irqreturn_t orion_wdt_irq(int irq, void *devid)
 243 {
 244         panic("Watchdog Timeout");
 245         return IRQ_HANDLED;
 246 }
 247
 248 /*
 249  * The original devicetree binding for this driver specified only
 250  * one memory resource, so in order to keep DT backwards compatibility
 251  * we try to fallback to a hardcoded register address, if the resource
 252  * is missing from the devicetree.
 253  */
 254 static void __iomem *orion_wdt_ioremap_rstout(struct platform_device *pdev,
 255                                               phys_addr_t internal_regs)
 256 {
 257         struct resource *res;
 258         phys_addr_t rstout;
 259
 260         res = platform_get_resource(pdev, IORESOURCE_MEM, 1);
 261         if (res)
 262                 return devm_ioremap(&pdev->dev, res->start,
 263                                     resource_size(res));
 264
 265         /* This workaround works only for "orion-wdt", DT-enabled */
 266         if (!of_device_is_compatible(pdev->dev.of_node, "marvell,orion-wdt"))
 267                 return NULL;
 268
 269         rstout = internal_regs + ORION_RSTOUT_MASK_OFFSET;
 270
 271         WARN(1, FW_BUG "falling back to harcoded RSTOUT reg %pa\n", &rstout);
 272         return devm_ioremap(&pdev->dev, rstout, 0x4);
 273 }
 274
 275 static const struct orion_watchdog_data orion_data = {
 276         .rstout_enable_bit = BIT(1),
 277         .wdt_enable_bit = BIT(4),
 278         .wdt_counter_offset = 0x24,
 279         .clock_init = orion_wdt_clock_init,
 280         .start = orion_start,
 281 };
 282
 283 static const struct orion_watchdog_data armada370_data = {
 284         .rstout_enable_bit = BIT(8),
 285         .wdt_enable_bit = BIT(8),
 286         .wdt_counter_offset = 0x34,
 287         .clock_init = armada370_wdt_clock_init,
 288         .start = armada370_start,
 289 };
 290
 291 static const struct orion_watchdog_data armadaxp_data = {
 292         .rstout_enable_bit = BIT(8),
 293         .wdt_enable_bit = BIT(8),
 294         .wdt_counter_offset = 0x34,
 295         .clock_init = armadaxp_wdt_clock_init,
 296         .start = armada370_start,
 297 };
 298
 299 static const struct of_device_id orion_wdt_of_match_table[] = {
 300         {
 301                 .compatible = "marvell,orion-wdt",
 302                 .data = &orion_data,
 303         },
 304         {
 305                 .compatible = "marvell,armada-370-wdt",
 306                 .data = &armada370_data,
 307         },
 308         {
 309                 .compatible = "marvell,armada-xp-wdt",
 310                 .data = &armadaxp_data,
 311         },
 312         {},
 313 };
 314 MODULE_DEVICE_TABLE(of, orion_wdt_of_match_table);
 315
 316 static int orion_wdt_probe(struct platform_device *pdev)
 317 {
 318         struct orion_watchdog *dev;
 319         const struct of_device_id *match;
 320         unsigned int wdt_max_duration;  /* (seconds) */
 321         struct resource *res;
 322         int ret, irq;
 323
 324         dev = devm_kzalloc(&pdev->dev, sizeof(struct orion_watchdog),
 325                            GFP_KERNEL);
 326         if (!dev)
 327                 return -ENOMEM;
 328
 329         match = of_match_device(orion_wdt_of_match_table, &pdev->dev);
 330         if (!match)
 331                 /* Default legacy match */
 332                 match = &orion_wdt_of_match_table[0];
 333
 334         dev->wdt.info = &orion_wdt_info;
 335         dev->wdt.ops = &orion_wdt_ops;
 336         dev->wdt.min_timeout = 1;
 337         dev->data = match->data;
 338
 339         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 340         if (!res)
 341                 return -ENODEV;
 342
 343         dev->reg = devm_ioremap(&pdev->dev, res->start,
 344                                resource_size(res));
 345         if (!dev->reg)
 346                 return -ENOMEM;
 347
 348         dev->rstout = orion_wdt_ioremap_rstout(pdev, res->start &
 349                                                      INTERNAL_REGS_MASK);
 350         if (!dev->rstout)
 351                 return -ENODEV;
 352
 353         ret = dev->data->clock_init(pdev, dev);
 354         if (ret) {
 355                 dev_err(&pdev->dev, "cannot initialize clock\n");
 356                 return ret;
 357         }
 358
 359         wdt_max_duration = WDT_MAX_CYCLE_COUNT / dev->clk_rate;
 360
 361         dev->wdt.timeout = wdt_max_duration;
 362         dev->wdt.max_timeout = wdt_max_duration;
 363         watchdog_init_timeout(&dev->wdt, heartbeat, &pdev->dev);
 364
 365         platform_set_drvdata(pdev, &dev->wdt);
 366         watchdog_set_drvdata(&dev->wdt, dev);
 367
 368         /*
 369          * Let's make sure the watchdog is fully stopped, unless it's
 370          * explicitly enabled. This may be the case if the module was
 371          * removed and re-insterted, or if the bootloader explicitly
 372          * set a running watchdog before booting the kernel.
 373          */
 374         if (!orion_wdt_enabled(dev))
 375                 orion_wdt_stop(&dev->wdt);
 376
 377         /* Request the IRQ only after the watchdog is disabled */
 378         irq = platform_get_irq(pdev, 0);
 379         if (irq > 0) {
 380                 /*
 381                  * Not all supported platforms specify an interrupt for the
 382                  * watchdog, so let's make it optional.
 383                  */
 384                 ret = devm_request_irq(&pdev->dev, irq, orion_wdt_irq, 0,
 385                                        pdev->name, dev);
 386                 if (ret < 0) {
 387                         dev_err(&pdev->dev, "failed to request IRQ\n");
 388                         goto disable_clk;
 389                 }
 390         }
 391
 392         watchdog_set_nowayout(&dev->wdt, nowayout);
 393         ret = watchdog_register_device(&dev->wdt);
 394         if (ret)
 395                 goto disable_clk;
 396
 397         pr_info("Initial timeout %d sec%s\n",
 398                 dev->wdt.timeout, nowayout ? ", nowayout" : "");
 399         return 0;
 400
 401 disable_clk:
 402         clk_disable_unprepare(dev->clk);
 403         clk_put(dev->clk);
 404         return ret;
 405 }
 406
 407 static int orion_wdt_remove(struct platform_device *pdev)
 408 {
 409         struct watchdog_device *wdt_dev = platform_get_drvdata(pdev);
 410         struct orion_watchdog *dev = watchdog_get_drvdata(wdt_dev);
 411
 412         watchdog_unregister_device(wdt_dev);
 413         clk_disable_unprepare(dev->clk);
 414         clk_put(dev->clk);
 415         return 0;
 416 }
 417
 418 static void orion_wdt_shutdown(struct platform_device *pdev)
 419 {
 420         struct watchdog_device *wdt_dev = platform_get_drvdata(pdev);
 421         orion_wdt_stop(wdt_dev);
 422 }
 423
 424 static struct platform_driver orion_wdt_driver = {
 425         .probe          = orion_wdt_probe,
 426         .remove         = orion_wdt_remove,
 427         .shutdown       = orion_wdt_shutdown,
 428         .driver         = {
 429                 .owner  = THIS_MODULE,
 430                 .name   = "orion_wdt",
 431                 .of_match_table = orion_wdt_of_match_table,
 432         },
 433 };
 434
 435 module_platform_driver(orion_wdt_driver);
 436
 437 MODULE_AUTHOR("Sylver Bruneau <sylver.bruneau@googlemail.com>");
 438 MODULE_DESCRIPTION("Orion Processor Watchdog");
 439
 440 module_param(heartbeat, int, 0);
 441 MODULE_PARM_DESC(heartbeat, "Initial watchdog heartbeat in seconds");
 442
 443 module_param(nowayout, bool, 0);
 444 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
 445                                 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
 446
 447 MODULE_LICENSE("GPL");
 448 MODULE_ALIAS("platform:orion_wdt");