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 (*enabled)(struct orion_watchdog *);
  61         int (*start)(struct watchdog_device *);
  62         int (*stop)(struct watchdog_device *);
  63 };
  64
  65 struct orion_watchdog {
  66         struct watchdog_device wdt;
  67         void __iomem *reg;
  68         void __iomem *rstout;
  69         unsigned long clk_rate;
  70         struct clk *clk;
  71         const struct orion_watchdog_data *data;
  72 };
  73
  74 static int orion_wdt_clock_init(struct platform_device *pdev,
  75                                 struct orion_watchdog *dev)
  76 {
  77         int ret;
  78
  79         dev->clk = clk_get(&pdev->dev, NULL);
  80         if (IS_ERR(dev->clk))
  81                 return PTR_ERR(dev->clk);
  82         ret = clk_prepare_enable(dev->clk);
  83         if (ret) {
  84                 clk_put(dev->clk);
  85                 return ret;
  86         }
  87
  88         dev->clk_rate = clk_get_rate(dev->clk);
  89         return 0;
  90 }
  91
  92 static int armada370_wdt_clock_init(struct platform_device *pdev,
  93                                     struct orion_watchdog *dev)
  94 {
  95         int ret;
  96
  97         dev->clk = clk_get(&pdev->dev, NULL);
  98         if (IS_ERR(dev->clk))
  99                 return PTR_ERR(dev->clk);
 100         ret = clk_prepare_enable(dev->clk);
 101         if (ret) {
 102                 clk_put(dev->clk);
 103                 return ret;
 104         }
 105
 106         /* Setup watchdog input clock */
 107         atomic_io_modify(dev->reg + TIMER_CTRL,
 108                         WDT_A370_RATIO_MASK(WDT_A370_RATIO_SHIFT),
 109                         WDT_A370_RATIO_MASK(WDT_A370_RATIO_SHIFT));
 110
 111         dev->clk_rate = clk_get_rate(dev->clk) / WDT_A370_RATIO;
 112         return 0;
 113 }
 114
 115 static int armadaxp_wdt_clock_init(struct platform_device *pdev,
 116                                    struct orion_watchdog *dev)
 117 {
 118         int ret;
 119
 120         dev->clk = of_clk_get_by_name(pdev->dev.of_node, "fixed");
 121         if (IS_ERR(dev->clk))
 122                 return PTR_ERR(dev->clk);
 123         ret = clk_prepare_enable(dev->clk);
 124         if (ret) {
 125                 clk_put(dev->clk);
 126                 return ret;
 127         }
 128
 129         /* Enable the fixed watchdog clock input */
 130         atomic_io_modify(dev->reg + TIMER_CTRL,
 131                          WDT_AXP_FIXED_ENABLE_BIT,
 132                          WDT_AXP_FIXED_ENABLE_BIT);
 133
 134         dev->clk_rate = clk_get_rate(dev->clk);
 135         return 0;
 136 }
 137
 138 static int orion_wdt_ping(struct watchdog_device *wdt_dev)
 139 {
 140         struct orion_watchdog *dev = watchdog_get_drvdata(wdt_dev);
 141         /* Reload watchdog duration */
 142         writel(dev->clk_rate * wdt_dev->timeout,
 143                dev->reg + dev->data->wdt_counter_offset);
 144         return 0;
 145 }
 146
 147 static int armada370_start(struct watchdog_device *wdt_dev)
 148 {
 149         struct orion_watchdog *dev = watchdog_get_drvdata(wdt_dev);
 150         u32 reg;
 151
 152         /* Set watchdog duration */
 153         writel(dev->clk_rate * wdt_dev->timeout,
 154                dev->reg + dev->data->wdt_counter_offset);
 155
 156         /* Clear the watchdog expiration bit */
 157         atomic_io_modify(dev->reg + TIMER_A370_STATUS, WDT_A370_EXPIRED, 0);
 158
 159         /* Enable watchdog timer */
 160         atomic_io_modify(dev->reg + TIMER_CTRL, dev->data->wdt_enable_bit,
 161                                                 dev->data->wdt_enable_bit);
 162
 163         /* Enable reset on watchdog */
 164         reg = readl(dev->rstout);
 165         reg |= dev->data->rstout_enable_bit;
 166         writel(reg, dev->rstout);
 167         return 0;
 168 }
 169
 170 static int orion_start(struct watchdog_device *wdt_dev)
 171 {
 172         struct orion_watchdog *dev = watchdog_get_drvdata(wdt_dev);
 173
 174         /* Set watchdog duration */
 175         writel(dev->clk_rate * wdt_dev->timeout,
 176                dev->reg + dev->data->wdt_counter_offset);
 177
 178         /* Enable watchdog timer */
 179         atomic_io_modify(dev->reg + TIMER_CTRL, dev->data->wdt_enable_bit,
 180                                                 dev->data->wdt_enable_bit);
 181
 182         /* Enable reset on watchdog */
 183         atomic_io_modify(dev->rstout, dev->data->rstout_enable_bit,
 184                                       dev->data->rstout_enable_bit);
 185
 186         return 0;
 187 }
 188
 189 static int orion_wdt_start(struct watchdog_device *wdt_dev)
 190 {
 191         struct orion_watchdog *dev = watchdog_get_drvdata(wdt_dev);
 192
 193         /* There are some per-SoC quirks to handle */
 194         return dev->data->start(wdt_dev);
 195 }
 196
 197 static int orion_stop(struct watchdog_device *wdt_dev)
 198 {
 199         struct orion_watchdog *dev = watchdog_get_drvdata(wdt_dev);
 200
 201         /* Disable reset on watchdog */
 202         atomic_io_modify(dev->rstout, dev->data->rstout_enable_bit, 0);
 203
 204         /* Disable watchdog timer */
 205         atomic_io_modify(dev->reg + TIMER_CTRL, dev->data->wdt_enable_bit, 0);
 206
 207         return 0;
 208 }
 209
 210 static int armada370_stop(struct watchdog_device *wdt_dev)
 211 {
 212         struct orion_watchdog *dev = watchdog_get_drvdata(wdt_dev);
 213         u32 reg;
 214
 215         /* Disable reset on watchdog */
 216         reg = readl(dev->rstout);
 217         reg &= ~dev->data->rstout_enable_bit;
 218         writel(reg, dev->rstout);
 219
 220         /* Disable watchdog timer */
 221         atomic_io_modify(dev->reg + TIMER_CTRL, dev->data->wdt_enable_bit, 0);
 222
 223         return 0;
 224 }
 225
 226 static int orion_wdt_stop(struct watchdog_device *wdt_dev)
 227 {
 228         struct orion_watchdog *dev = watchdog_get_drvdata(wdt_dev);
 229
 230         return dev->data->stop(wdt_dev);
 231 }
 232
 233 static int orion_enabled(struct orion_watchdog *dev)
 234 {
 235         bool enabled, running;
 236
 237         enabled = readl(dev->rstout) & dev->data->rstout_enable_bit;
 238         running = readl(dev->reg + TIMER_CTRL) & dev->data->wdt_enable_bit;
 239
 240         return enabled && running;
 241 }
 242
 243 static int orion_wdt_enabled(struct watchdog_device *wdt_dev)
 244 {
 245         struct orion_watchdog *dev = watchdog_get_drvdata(wdt_dev);
 246
 247         return dev->data->enabled(dev);
 248 }
 249
 250 static unsigned int orion_wdt_get_timeleft(struct watchdog_device *wdt_dev)
 251 {
 252         struct orion_watchdog *dev = watchdog_get_drvdata(wdt_dev);
 253         return readl(dev->reg + dev->data->wdt_counter_offset) / dev->clk_rate;
 254 }
 255
 256 static int orion_wdt_set_timeout(struct watchdog_device *wdt_dev,
 257                                  unsigned int timeout)
 258 {
 259         wdt_dev->timeout = timeout;
 260         return 0;
 261 }
 262
 263 static const struct watchdog_info orion_wdt_info = {
 264         .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
 265         .identity = "Orion Watchdog",
 266 };
 267
 268 static const struct watchdog_ops orion_wdt_ops = {
 269         .owner = THIS_MODULE,
 270         .start = orion_wdt_start,
 271         .stop = orion_wdt_stop,
 272         .ping = orion_wdt_ping,
 273         .set_timeout = orion_wdt_set_timeout,
 274         .get_timeleft = orion_wdt_get_timeleft,
 275 };
 276
 277 static irqreturn_t orion_wdt_irq(int irq, void *devid)
 278 {
 279         panic("Watchdog Timeout");
 280         return IRQ_HANDLED;
 281 }
 282
 283 /*
 284  * The original devicetree binding for this driver specified only
 285  * one memory resource, so in order to keep DT backwards compatibility
 286  * we try to fallback to a hardcoded register address, if the resource
 287  * is missing from the devicetree.
 288  */
 289 static void __iomem *orion_wdt_ioremap_rstout(struct platform_device *pdev,
 290                                               phys_addr_t internal_regs)
 291 {
 292         struct resource *res;
 293         phys_addr_t rstout;
 294
 295         res = platform_get_resource(pdev, IORESOURCE_MEM, 1);
 296         if (res)
 297                 return devm_ioremap(&pdev->dev, res->start,
 298                                     resource_size(res));
 299
 300         rstout = internal_regs + ORION_RSTOUT_MASK_OFFSET;
 301
 302         WARN(1, FW_BUG "falling back to harcoded RSTOUT reg %pa\n", &rstout);
 303         return devm_ioremap(&pdev->dev, rstout, 0x4);
 304 }
 305
 306 static const struct orion_watchdog_data orion_data = {
 307         .rstout_enable_bit = BIT(1),
 308         .wdt_enable_bit = BIT(4),
 309         .wdt_counter_offset = 0x24,
 310         .clock_init = orion_wdt_clock_init,
 311         .enabled = orion_enabled,
 312         .start = orion_start,
 313         .stop = orion_stop,
 314 };
 315
 316 static const struct orion_watchdog_data armada370_data = {
 317         .rstout_enable_bit = BIT(8),
 318         .wdt_enable_bit = BIT(8),
 319         .wdt_counter_offset = 0x34,
 320         .clock_init = armada370_wdt_clock_init,
 321         .enabled = orion_enabled,
 322         .start = armada370_start,
 323         .stop = armada370_stop,
 324 };
 325
 326 static const struct orion_watchdog_data armadaxp_data = {
 327         .rstout_enable_bit = BIT(8),
 328         .wdt_enable_bit = BIT(8),
 329         .wdt_counter_offset = 0x34,
 330         .clock_init = armadaxp_wdt_clock_init,
 331         .enabled = orion_enabled,
 332         .start = armada370_start,
 333         .stop = armada370_stop,
 334 };
 335
 336 static const struct of_device_id orion_wdt_of_match_table[] = {
 337         {
 338                 .compatible = "marvell,orion-wdt",
 339                 .data = &orion_data,
 340         },
 341         {
 342                 .compatible = "marvell,armada-370-wdt",
 343                 .data = &armada370_data,
 344         },
 345         {
 346                 .compatible = "marvell,armada-xp-wdt",
 347                 .data = &armadaxp_data,
 348         },
 349         {},
 350 };
 351 MODULE_DEVICE_TABLE(of, orion_wdt_of_match_table);
 352
 353 static int orion_wdt_get_regs(struct platform_device *pdev,
 354                               struct orion_watchdog *dev)
 355 {
 356         struct device_node *node = pdev->dev.of_node;
 357         struct resource *res;
 358
 359         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 360         if (!res)
 361                 return -ENODEV;
 362         dev->reg = devm_ioremap(&pdev->dev, res->start,
 363                                 resource_size(res));
 364         if (!dev->reg)
 365                 return -ENOMEM;
 366
 367         /* Each supported compatible has some RSTOUT register quirk */
 368         if (of_device_is_compatible(node, "marvell,orion-wdt")) {
 369
 370                 dev->rstout = orion_wdt_ioremap_rstout(pdev, res->start &
 371                                                        INTERNAL_REGS_MASK);
 372                 if (!dev->rstout)
 373                         return -ENODEV;
 374
 375         } else if (of_device_is_compatible(node, "marvell,armada-370-wdt") ||
 376                    of_device_is_compatible(node, "marvell,armada-xp-wdt")) {
 377
 378                 /* Dedicated RSTOUT register, can be requested. */
 379                 res = platform_get_resource(pdev, IORESOURCE_MEM, 1);
 380                 dev->rstout = devm_ioremap_resource(&pdev->dev, res);
 381                 if (IS_ERR(dev->rstout))
 382                         return PTR_ERR(dev->rstout);
 383
 384         } else {
 385                 return -ENODEV;
 386         }
 387
 388         return 0;
 389 }
 390
 391 static int orion_wdt_probe(struct platform_device *pdev)
 392 {
 393         struct orion_watchdog *dev;
 394         const struct of_device_id *match;
 395         unsigned int wdt_max_duration;  /* (seconds) */
 396         int ret, irq;
 397
 398         dev = devm_kzalloc(&pdev->dev, sizeof(struct orion_watchdog),
 399                            GFP_KERNEL);
 400         if (!dev)
 401                 return -ENOMEM;
 402
 403         match = of_match_device(orion_wdt_of_match_table, &pdev->dev);
 404         if (!match)
 405                 /* Default legacy match */
 406                 match = &orion_wdt_of_match_table[0];
 407
 408         dev->wdt.info = &orion_wdt_info;
 409         dev->wdt.ops = &orion_wdt_ops;
 410         dev->wdt.min_timeout = 1;
 411         dev->data = match->data;
 412
 413         ret = orion_wdt_get_regs(pdev, dev);
 414         if (ret)
 415                 return ret;
 416
 417         ret = dev->data->clock_init(pdev, dev);
 418         if (ret) {
 419                 dev_err(&pdev->dev, "cannot initialize clock\n");
 420                 return ret;
 421         }
 422
 423         wdt_max_duration = WDT_MAX_CYCLE_COUNT / dev->clk_rate;
 424
 425         dev->wdt.timeout = wdt_max_duration;
 426         dev->wdt.max_timeout = wdt_max_duration;
 427         watchdog_init_timeout(&dev->wdt, heartbeat, &pdev->dev);
 428
 429         platform_set_drvdata(pdev, &dev->wdt);
 430         watchdog_set_drvdata(&dev->wdt, dev);
 431
 432         /*
 433          * Let's make sure the watchdog is fully stopped, unless it's
 434          * explicitly enabled. This may be the case if the module was
 435          * removed and re-insterted, or if the bootloader explicitly
 436          * set a running watchdog before booting the kernel.
 437          */
 438         if (!orion_wdt_enabled(&dev->wdt))
 439                 orion_wdt_stop(&dev->wdt);
 440
 441         /* Request the IRQ only after the watchdog is disabled */
 442         irq = platform_get_irq(pdev, 0);
 443         if (irq > 0) {
 444                 /*
 445                  * Not all supported platforms specify an interrupt for the
 446                  * watchdog, so let's make it optional.
 447                  */
 448                 ret = devm_request_irq(&pdev->dev, irq, orion_wdt_irq, 0,
 449                                        pdev->name, dev);
 450                 if (ret < 0) {
 451                         dev_err(&pdev->dev, "failed to request IRQ\n");
 452                         goto disable_clk;
 453                 }
 454         }
 455
 456         watchdog_set_nowayout(&dev->wdt, nowayout);
 457         ret = watchdog_register_device(&dev->wdt);
 458         if (ret)
 459                 goto disable_clk;
 460
 461         pr_info("Initial timeout %d sec%s\n",
 462                 dev->wdt.timeout, nowayout ? ", nowayout" : "");
 463         return 0;
 464
 465 disable_clk:
 466         clk_disable_unprepare(dev->clk);
 467         clk_put(dev->clk);
 468         return ret;
 469 }
 470
 471 static int orion_wdt_remove(struct platform_device *pdev)
 472 {
 473         struct watchdog_device *wdt_dev = platform_get_drvdata(pdev);
 474         struct orion_watchdog *dev = watchdog_get_drvdata(wdt_dev);
 475
 476         watchdog_unregister_device(wdt_dev);
 477         clk_disable_unprepare(dev->clk);
 478         clk_put(dev->clk);
 479         return 0;
 480 }
 481
 482 static void orion_wdt_shutdown(struct platform_device *pdev)
 483 {
 484         struct watchdog_device *wdt_dev = platform_get_drvdata(pdev);
 485         orion_wdt_stop(wdt_dev);
 486 }
 487
 488 static struct platform_driver orion_wdt_driver = {
 489         .probe          = orion_wdt_probe,
 490         .remove         = orion_wdt_remove,
 491         .shutdown       = orion_wdt_shutdown,
 492         .driver         = {
 493                 .owner  = THIS_MODULE,
 494                 .name   = "orion_wdt",
 495                 .of_match_table = orion_wdt_of_match_table,
 496         },
 497 };
 498
 499 module_platform_driver(orion_wdt_driver);
 500
 501 MODULE_AUTHOR("Sylver Bruneau <sylver.bruneau@googlemail.com>");
 502 MODULE_DESCRIPTION("Orion Processor Watchdog");
 503
 504 module_param(heartbeat, int, 0);
 505 MODULE_PARM_DESC(heartbeat, "Initial watchdog heartbeat in seconds");
 506
 507 module_param(nowayout, bool, 0);
 508 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
 509                                 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
 510
 511 MODULE_LICENSE("GPL");
 512 MODULE_ALIAS("platform:orion_wdt");