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