drivers/watchdog/imx7ulp_wdt.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Copyright 2019 NXP.
   4  */
   5
   6 #include <linux/clk.h>
   7 #include <linux/io.h>
   8 #include <linux/iopoll.h>
   9 #include <linux/kernel.h>
  10 #include <linux/module.h>
  11 #include <linux/of.h>
  12 #include <linux/platform_device.h>
  13 #include <linux/reboot.h>
  14 #include <linux/watchdog.h>
  15
  16 #define WDOG_CS                 0x0
  17 #define WDOG_CS_FLG             BIT(14)
  18 #define WDOG_CS_CMD32EN         BIT(13)
  19 #define WDOG_CS_PRES            BIT(12)
  20 #define WDOG_CS_ULK             BIT(11)
  21 #define WDOG_CS_RCS             BIT(10)
  22 #define LPO_CLK                 0x1
  23 #define LPO_CLK_SHIFT           8
  24 #define WDOG_CS_CLK             (LPO_CLK << LPO_CLK_SHIFT)
  25 #define WDOG_CS_EN              BIT(7)
  26 #define WDOG_CS_INT_EN          BIT(6)
  27 #define WDOG_CS_UPDATE          BIT(5)
  28 #define WDOG_CS_WAIT            BIT(1)
  29 #define WDOG_CS_STOP            BIT(0)
  30
  31 #define WDOG_CNT        0x4
  32 #define WDOG_TOVAL      0x8
  33
  34 #define REFRESH_SEQ0    0xA602
  35 #define REFRESH_SEQ1    0xB480
  36 #define REFRESH         ((REFRESH_SEQ1 << 16) | REFRESH_SEQ0)
  37
  38 #define UNLOCK_SEQ0     0xC520
  39 #define UNLOCK_SEQ1     0xD928
  40 #define UNLOCK          ((UNLOCK_SEQ1 << 16) | UNLOCK_SEQ0)
  41
  42 #define DEFAULT_TIMEOUT 60
  43 #define MAX_TIMEOUT     128
  44 #define WDOG_CLOCK_RATE 1000
  45 #define WDOG_ULK_WAIT_TIMEOUT   1000
  46 #define WDOG_RCS_WAIT_TIMEOUT   10000
  47 #define WDOG_RCS_POST_WAIT 3000
  48
  49 #define RETRY_MAX 5
  50
  51 static bool nowayout = WATCHDOG_NOWAYOUT;
  52 module_param(nowayout, bool, 0000);
  53 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
  54                  __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
  55
  56 struct imx_wdt_hw_feature {
  57         bool prescaler_enable;
  58         bool post_rcs_wait;
  59         u32 wdog_clock_rate;
  60 };
  61
  62 struct imx7ulp_wdt_device {
  63         struct watchdog_device wdd;
  64         void __iomem *base;
  65         struct clk *clk;
  66         bool ext_reset;
  67         const struct imx_wdt_hw_feature *hw;
  68 };
  69
  70 static int imx7ulp_wdt_wait_ulk(void __iomem *base)
  71 {
  72         u32 val = readl(base + WDOG_CS);
  73
  74         if (!(val & WDOG_CS_ULK) &&
  75             readl_poll_timeout_atomic(base + WDOG_CS, val,
  76                                       val & WDOG_CS_ULK, 0,
  77                                       WDOG_ULK_WAIT_TIMEOUT))
  78                 return -ETIMEDOUT;
  79
  80         return 0;
  81 }
  82
  83 static int imx7ulp_wdt_wait_rcs(struct imx7ulp_wdt_device *wdt)
  84 {
  85         int ret = 0;
  86         u32 val = readl(wdt->base + WDOG_CS);
  87         u64 timeout = (val & WDOG_CS_PRES) ?
  88                 WDOG_RCS_WAIT_TIMEOUT * 256 : WDOG_RCS_WAIT_TIMEOUT;
  89         unsigned long wait_min = (val & WDOG_CS_PRES) ?
  90                 WDOG_RCS_POST_WAIT * 256 : WDOG_RCS_POST_WAIT;
  91
  92         if (!(val & WDOG_CS_RCS) &&
  93             readl_poll_timeout(wdt->base + WDOG_CS, val, val & WDOG_CS_RCS, 100,
  94                                timeout))
  95                 ret = -ETIMEDOUT;
  96
  97         /* Wait 2.5 clocks after RCS done */
  98         if (wdt->hw->post_rcs_wait)
  99                 usleep_range(wait_min, wait_min + 2000);
 100
 101         return ret;
 102 }
 103
 104 static int _imx7ulp_wdt_enable(struct imx7ulp_wdt_device *wdt, bool enable)
 105 {
 106         u32 val = readl(wdt->base + WDOG_CS);
 107         int ret;
 108
 109         local_irq_disable();
 110         writel(UNLOCK, wdt->base + WDOG_CNT);
 111         ret = imx7ulp_wdt_wait_ulk(wdt->base);
 112         if (ret)
 113                 goto enable_out;
 114         if (enable)
 115                 writel(val | WDOG_CS_EN, wdt->base + WDOG_CS);
 116         else
 117                 writel(val & ~WDOG_CS_EN, wdt->base + WDOG_CS);
 118
 119         local_irq_enable();
 120         ret = imx7ulp_wdt_wait_rcs(wdt);
 121
 122         return ret;
 123
 124 enable_out:
 125         local_irq_enable();
 126         return ret;
 127 }
 128
 129 static int imx7ulp_wdt_enable(struct watchdog_device *wdog, bool enable)
 130 {
 131         struct imx7ulp_wdt_device *wdt = watchdog_get_drvdata(wdog);
 132         int ret;
 133         u32 val;
 134         u32 loop = RETRY_MAX;
 135
 136         do {
 137                 ret = _imx7ulp_wdt_enable(wdt, enable);
 138                 val = readl(wdt->base + WDOG_CS);
 139         } while (--loop > 0 && ((!!(val & WDOG_CS_EN)) != enable || ret));
 140
 141         if (loop == 0)
 142                 return -EBUSY;
 143
 144         return ret;
 145 }
 146
 147 static int imx7ulp_wdt_ping(struct watchdog_device *wdog)
 148 {
 149         struct imx7ulp_wdt_device *wdt = watchdog_get_drvdata(wdog);
 150
 151         writel(REFRESH, wdt->base + WDOG_CNT);
 152
 153         return 0;
 154 }
 155
 156 static int imx7ulp_wdt_start(struct watchdog_device *wdog)
 157 {
 158         return imx7ulp_wdt_enable(wdog, true);
 159 }
 160
 161 static int imx7ulp_wdt_stop(struct watchdog_device *wdog)
 162 {
 163         return imx7ulp_wdt_enable(wdog, false);
 164 }
 165
 166 static int _imx7ulp_wdt_set_timeout(struct imx7ulp_wdt_device *wdt,
 167                                    unsigned int toval)
 168 {
 169         int ret;
 170
 171         local_irq_disable();
 172         writel(UNLOCK, wdt->base + WDOG_CNT);
 173         ret = imx7ulp_wdt_wait_ulk(wdt->base);
 174         if (ret)
 175                 goto timeout_out;
 176         writel(toval, wdt->base + WDOG_TOVAL);
 177         local_irq_enable();
 178         ret = imx7ulp_wdt_wait_rcs(wdt);
 179         return ret;
 180
 181 timeout_out:
 182         local_irq_enable();
 183         return ret;
 184 }
 185
 186 static int imx7ulp_wdt_set_timeout(struct watchdog_device *wdog,
 187                                    unsigned int timeout)
 188 {
 189         struct imx7ulp_wdt_device *wdt = watchdog_get_drvdata(wdog);
 190         u32 toval = wdt->hw->wdog_clock_rate * timeout;
 191         u32 val;
 192         int ret;
 193         u32 loop = RETRY_MAX;
 194
 195         do {
 196                 ret = _imx7ulp_wdt_set_timeout(wdt, toval);
 197                 val = readl(wdt->base + WDOG_TOVAL);
 198         } while (--loop > 0 && (val != toval || ret));
 199
 200         if (loop == 0)
 201                 return -EBUSY;
 202
 203         wdog->timeout = timeout;
 204         return ret;
 205 }
 206
 207 static int imx7ulp_wdt_restart(struct watchdog_device *wdog,
 208                                unsigned long action, void *data)
 209 {
 210         struct imx7ulp_wdt_device *wdt = watchdog_get_drvdata(wdog);
 211         int ret;
 212
 213         ret = imx7ulp_wdt_enable(wdog, true);
 214         if (ret)
 215                 return ret;
 216
 217         ret = imx7ulp_wdt_set_timeout(&wdt->wdd, 1);
 218         if (ret)
 219                 return ret;
 220
 221         /* wait for wdog to fire */
 222         while (true)
 223                 ;
 224
 225         return NOTIFY_DONE;
 226 }
 227
 228 static const struct watchdog_ops imx7ulp_wdt_ops = {
 229         .owner = THIS_MODULE,
 230         .start = imx7ulp_wdt_start,
 231         .stop  = imx7ulp_wdt_stop,
 232         .ping  = imx7ulp_wdt_ping,
 233         .set_timeout = imx7ulp_wdt_set_timeout,
 234         .restart = imx7ulp_wdt_restart,
 235 };
 236
 237 static const struct watchdog_info imx7ulp_wdt_info = {
 238         .identity = "i.MX7ULP watchdog timer",
 239         .options  = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING |
 240                     WDIOF_MAGICCLOSE,
 241 };
 242
 243 static int _imx7ulp_wdt_init(struct imx7ulp_wdt_device *wdt, unsigned int timeout, unsigned int cs)
 244 {
 245         u32 val;
 246         int ret;
 247
 248         local_irq_disable();
 249
 250         val = readl(wdt->base + WDOG_CS);
 251         if (val & WDOG_CS_CMD32EN) {
 252                 writel(UNLOCK, wdt->base + WDOG_CNT);
 253         } else {
 254                 mb();
 255                 /* unlock the wdog for reconfiguration */
 256                 writel_relaxed(UNLOCK_SEQ0, wdt->base + WDOG_CNT);
 257                 writel_relaxed(UNLOCK_SEQ1, wdt->base + WDOG_CNT);
 258                 mb();
 259         }
 260
 261         ret = imx7ulp_wdt_wait_ulk(wdt->base);
 262         if (ret)
 263                 goto init_out;
 264
 265         /* set an initial timeout value in TOVAL */
 266         writel(timeout, wdt->base + WDOG_TOVAL);
 267         writel(cs, wdt->base + WDOG_CS);
 268         local_irq_enable();
 269         ret = imx7ulp_wdt_wait_rcs(wdt);
 270
 271         return ret;
 272
 273 init_out:
 274         local_irq_enable();
 275         return ret;
 276 }
 277
 278 static int imx7ulp_wdt_init(struct imx7ulp_wdt_device *wdt, unsigned int timeout)
 279 {
 280         /* enable 32bit command sequence and reconfigure */
 281         u32 val = WDOG_CS_CMD32EN | WDOG_CS_CLK | WDOG_CS_UPDATE |
 282                   WDOG_CS_WAIT | WDOG_CS_STOP;
 283         u32 cs, toval;
 284         int ret;
 285         u32 loop = RETRY_MAX;
 286
 287         if (wdt->hw->prescaler_enable)
 288                 val |= WDOG_CS_PRES;
 289
 290         if (wdt->ext_reset)
 291                 val |= WDOG_CS_INT_EN;
 292
 293         if (readl(wdt->base + WDOG_CS) & WDOG_CS_EN) {
 294                 set_bit(WDOG_HW_RUNNING, &wdt->wdd.status);
 295                 val |= WDOG_CS_EN;
 296         }
 297
 298         do {
 299                 ret = _imx7ulp_wdt_init(wdt, timeout, val);
 300                 toval = readl(wdt->base + WDOG_TOVAL);
 301                 cs = readl(wdt->base + WDOG_CS);
 302                 cs &= ~(WDOG_CS_FLG | WDOG_CS_ULK | WDOG_CS_RCS);
 303         } while (--loop > 0 && (cs != val || toval != timeout || ret));
 304
 305         if (loop == 0)
 306                 return -EBUSY;
 307
 308         return ret;
 309 }
 310
 311 static int imx7ulp_wdt_probe(struct platform_device *pdev)
 312 {
 313         struct imx7ulp_wdt_device *imx7ulp_wdt;
 314         struct device *dev = &pdev->dev;
 315         struct watchdog_device *wdog;
 316         int ret;
 317
 318         imx7ulp_wdt = devm_kzalloc(dev, sizeof(*imx7ulp_wdt), GFP_KERNEL);
 319         if (!imx7ulp_wdt)
 320                 return -ENOMEM;
 321
 322         platform_set_drvdata(pdev, imx7ulp_wdt);
 323
 324         imx7ulp_wdt->base = devm_platform_ioremap_resource(pdev, 0);
 325         if (IS_ERR(imx7ulp_wdt->base))
 326                 return PTR_ERR(imx7ulp_wdt->base);
 327
 328         imx7ulp_wdt->clk = devm_clk_get_enabled(dev, NULL);
 329         if (IS_ERR(imx7ulp_wdt->clk)) {
 330                 dev_err(dev, "Failed to get watchdog clock\n");
 331                 return PTR_ERR(imx7ulp_wdt->clk);
 332         }
 333
 334         /* The WDOG may need to do external reset through dedicated pin */
 335         imx7ulp_wdt->ext_reset = of_property_read_bool(dev->of_node, "fsl,ext-reset-output");
 336
 337         wdog = &imx7ulp_wdt->wdd;
 338         wdog->info = &imx7ulp_wdt_info;
 339         wdog->ops = &imx7ulp_wdt_ops;
 340         wdog->min_timeout = 1;
 341         wdog->max_timeout = MAX_TIMEOUT;
 342         wdog->parent = dev;
 343         wdog->timeout = DEFAULT_TIMEOUT;
 344
 345         watchdog_init_timeout(wdog, 0, dev);
 346         watchdog_stop_on_reboot(wdog);
 347         watchdog_stop_on_unregister(wdog);
 348         watchdog_set_drvdata(wdog, imx7ulp_wdt);
 349
 350         imx7ulp_wdt->hw = of_device_get_match_data(dev);
 351         ret = imx7ulp_wdt_init(imx7ulp_wdt, wdog->timeout * imx7ulp_wdt->hw->wdog_clock_rate);
 352         if (ret)
 353                 return ret;
 354
 355         return devm_watchdog_register_device(dev, wdog);
 356 }
 357
 358 static int __maybe_unused imx7ulp_wdt_suspend_noirq(struct device *dev)
 359 {
 360         struct imx7ulp_wdt_device *imx7ulp_wdt = dev_get_drvdata(dev);
 361
 362         if (watchdog_active(&imx7ulp_wdt->wdd))
 363                 imx7ulp_wdt_stop(&imx7ulp_wdt->wdd);
 364
 365         clk_disable_unprepare(imx7ulp_wdt->clk);
 366
 367         return 0;
 368 }
 369
 370 static int __maybe_unused imx7ulp_wdt_resume_noirq(struct device *dev)
 371 {
 372         struct imx7ulp_wdt_device *imx7ulp_wdt = dev_get_drvdata(dev);
 373         u32 timeout = imx7ulp_wdt->wdd.timeout * imx7ulp_wdt->hw->wdog_clock_rate;
 374         int ret;
 375
 376         ret = clk_prepare_enable(imx7ulp_wdt->clk);
 377         if (ret)
 378                 return ret;
 379
 380         if (watchdog_active(&imx7ulp_wdt->wdd)) {
 381                 imx7ulp_wdt_init(imx7ulp_wdt, timeout);
 382                 imx7ulp_wdt_start(&imx7ulp_wdt->wdd);
 383                 imx7ulp_wdt_ping(&imx7ulp_wdt->wdd);
 384         }
 385
 386         return 0;
 387 }
 388
 389 static const struct dev_pm_ops imx7ulp_wdt_pm_ops = {
 390         SET_NOIRQ_SYSTEM_SLEEP_PM_OPS(imx7ulp_wdt_suspend_noirq,
 391                                       imx7ulp_wdt_resume_noirq)
 392 };
 393
 394 static const struct imx_wdt_hw_feature imx7ulp_wdt_hw = {
 395         .prescaler_enable = false,
 396         .wdog_clock_rate = 1000,
 397         .post_rcs_wait = true,
 398 };
 399
 400 static const struct imx_wdt_hw_feature imx8ulp_wdt_hw = {
 401         .prescaler_enable = false,
 402         .wdog_clock_rate = 1000,
 403 };
 404
 405 static const struct imx_wdt_hw_feature imx93_wdt_hw = {
 406         .prescaler_enable = true,
 407         .wdog_clock_rate = 125,
 408 };
 409
 410 static const struct of_device_id imx7ulp_wdt_dt_ids[] = {
 411         { .compatible = "fsl,imx7ulp-wdt", .data = &imx7ulp_wdt_hw, },
 412         { .compatible = "fsl,imx8ulp-wdt", .data = &imx8ulp_wdt_hw, },
 413         { .compatible = "fsl,imx93-wdt", .data = &imx93_wdt_hw, },
 414         { /* sentinel */ }
 415 };
 416 MODULE_DEVICE_TABLE(of, imx7ulp_wdt_dt_ids);
 417
 418 static struct platform_driver imx7ulp_wdt_driver = {
 419         .probe          = imx7ulp_wdt_probe,
 420         .driver         = {
 421                 .name   = "imx7ulp-wdt",
 422                 .pm     = &imx7ulp_wdt_pm_ops,
 423                 .of_match_table = imx7ulp_wdt_dt_ids,
 424         },
 425 };
 426 module_platform_driver(imx7ulp_wdt_driver);
 427
 428 MODULE_AUTHOR("Anson Huang <[email protected]>");
 429 MODULE_DESCRIPTION("Freescale i.MX7ULP watchdog driver");
 430 MODULE_LICENSE("GPL v2");