drivers/watchdog/sprd_wdt.c

   1 /*
   2  * Spreadtrum watchdog driver
   3  * Copyright (C) 2017 Spreadtrum - http://www.spreadtrum.com
   4  *
   5  * This program is free software; you can redistribute it and/or
   6  * modify it under the terms of the GNU General Public License
   7  * version 2 as published by the Free Software Foundation.
   8  *
   9  * This program is distributed in the hope that it will be useful, but
  10  * WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12  * General Public License for more details.
  13  */
  14
  15 #include <linux/bitops.h>
  16 #include <linux/clk.h>
  17 #include <linux/device.h>
  18 #include <linux/err.h>
  19 #include <linux/interrupt.h>
  20 #include <linux/io.h>
  21 #include <linux/kernel.h>
  22 #include <linux/module.h>
  23 #include <linux/of.h>
  24 #include <linux/of_address.h>
  25 #include <linux/platform_device.h>
  26 #include <linux/watchdog.h>
  27
  28 #define SPRD_WDT_LOAD_LOW               0x0
  29 #define SPRD_WDT_LOAD_HIGH              0x4
  30 #define SPRD_WDT_CTRL                   0x8
  31 #define SPRD_WDT_INT_CLR                0xc
  32 #define SPRD_WDT_INT_RAW                0x10
  33 #define SPRD_WDT_INT_MSK                0x14
  34 #define SPRD_WDT_CNT_LOW                0x18
  35 #define SPRD_WDT_CNT_HIGH               0x1c
  36 #define SPRD_WDT_LOCK                   0x20
  37 #define SPRD_WDT_IRQ_LOAD_LOW           0x2c
  38 #define SPRD_WDT_IRQ_LOAD_HIGH          0x30
  39
  40 /* WDT_CTRL */
  41 #define SPRD_WDT_INT_EN_BIT             BIT(0)
  42 #define SPRD_WDT_CNT_EN_BIT             BIT(1)
  43 #define SPRD_WDT_NEW_VER_EN             BIT(2)
  44 #define SPRD_WDT_RST_EN_BIT             BIT(3)
  45
  46 /* WDT_INT_CLR */
  47 #define SPRD_WDT_INT_CLEAR_BIT          BIT(0)
  48 #define SPRD_WDT_RST_CLEAR_BIT          BIT(3)
  49
  50 /* WDT_INT_RAW */
  51 #define SPRD_WDT_INT_RAW_BIT            BIT(0)
  52 #define SPRD_WDT_RST_RAW_BIT            BIT(3)
  53 #define SPRD_WDT_LD_BUSY_BIT            BIT(4)
  54
  55 /* 1s equal to 32768 counter steps */
  56 #define SPRD_WDT_CNT_STEP               32768
  57
  58 #define SPRD_WDT_UNLOCK_KEY             0xe551
  59 #define SPRD_WDT_MIN_TIMEOUT            3
  60 #define SPRD_WDT_MAX_TIMEOUT            60
  61
  62 #define SPRD_WDT_CNT_HIGH_SHIFT         16
  63 #define SPRD_WDT_LOW_VALUE_MASK         GENMASK(15, 0)
  64 #define SPRD_WDT_LOAD_TIMEOUT           1000
  65
  66 struct sprd_wdt {
  67         void __iomem *base;
  68         struct watchdog_device wdd;
  69         struct clk *enable;
  70         struct clk *rtc_enable;
  71         int irq;
  72 };
  73
  74 static inline struct sprd_wdt *to_sprd_wdt(struct watchdog_device *wdd)
  75 {
  76         return container_of(wdd, struct sprd_wdt, wdd);
  77 }
  78
  79 static inline void sprd_wdt_lock(void __iomem *addr)
  80 {
  81         writel_relaxed(0x0, addr + SPRD_WDT_LOCK);
  82 }
  83
  84 static inline void sprd_wdt_unlock(void __iomem *addr)
  85 {
  86         writel_relaxed(SPRD_WDT_UNLOCK_KEY, addr + SPRD_WDT_LOCK);
  87 }
  88
  89 static irqreturn_t sprd_wdt_isr(int irq, void *dev_id)
  90 {
  91         struct sprd_wdt *wdt = (struct sprd_wdt *)dev_id;
  92
  93         sprd_wdt_unlock(wdt->base);
  94         writel_relaxed(SPRD_WDT_INT_CLEAR_BIT, wdt->base + SPRD_WDT_INT_CLR);
  95         sprd_wdt_lock(wdt->base);
  96         watchdog_notify_pretimeout(&wdt->wdd);
  97         return IRQ_HANDLED;
  98 }
  99
 100 static u32 sprd_wdt_get_cnt_value(struct sprd_wdt *wdt)
 101 {
 102         u32 val;
 103
 104         val = readl_relaxed(wdt->base + SPRD_WDT_CNT_HIGH) <<
 105                 SPRD_WDT_CNT_HIGH_SHIFT;
 106         val |= readl_relaxed(wdt->base + SPRD_WDT_CNT_LOW) &
 107                 SPRD_WDT_LOW_VALUE_MASK;
 108
 109         return val;
 110 }
 111
 112 static int sprd_wdt_load_value(struct sprd_wdt *wdt, u32 timeout,
 113                                u32 pretimeout)
 114 {
 115         u32 val, delay_cnt = 0;
 116         u32 tmr_step = timeout * SPRD_WDT_CNT_STEP;
 117         u32 prtmr_step = pretimeout * SPRD_WDT_CNT_STEP;
 118
 119         /*
 120          * Waiting the load value operation done,
 121          * it needs two or three RTC clock cycles.
 122          */
 123         do {
 124                 val = readl_relaxed(wdt->base + SPRD_WDT_INT_RAW);
 125                 if (!(val & SPRD_WDT_LD_BUSY_BIT))
 126                         break;
 127
 128                 cpu_relax();
 129         } while (delay_cnt++ < SPRD_WDT_LOAD_TIMEOUT);
 130
 131         if (delay_cnt >= SPRD_WDT_LOAD_TIMEOUT)
 132                 return -EBUSY;
 133
 134         sprd_wdt_unlock(wdt->base);
 135         writel_relaxed((tmr_step >> SPRD_WDT_CNT_HIGH_SHIFT) &
 136                       SPRD_WDT_LOW_VALUE_MASK, wdt->base + SPRD_WDT_LOAD_HIGH);
 137         writel_relaxed((tmr_step & SPRD_WDT_LOW_VALUE_MASK),
 138                        wdt->base + SPRD_WDT_LOAD_LOW);
 139         writel_relaxed((prtmr_step >> SPRD_WDT_CNT_HIGH_SHIFT) &
 140                         SPRD_WDT_LOW_VALUE_MASK,
 141                        wdt->base + SPRD_WDT_IRQ_LOAD_HIGH);
 142         writel_relaxed(prtmr_step & SPRD_WDT_LOW_VALUE_MASK,
 143                        wdt->base + SPRD_WDT_IRQ_LOAD_LOW);
 144         sprd_wdt_lock(wdt->base);
 145
 146         return 0;
 147 }
 148
 149 static int sprd_wdt_enable(struct sprd_wdt *wdt)
 150 {
 151         u32 val;
 152         int ret;
 153
 154         ret = clk_prepare_enable(wdt->enable);
 155         if (ret)
 156                 return ret;
 157         ret = clk_prepare_enable(wdt->rtc_enable);
 158         if (ret) {
 159                 clk_disable_unprepare(wdt->enable);
 160                 return ret;
 161         }
 162
 163         sprd_wdt_unlock(wdt->base);
 164         val = readl_relaxed(wdt->base + SPRD_WDT_CTRL);
 165         val |= SPRD_WDT_NEW_VER_EN;
 166         writel_relaxed(val, wdt->base + SPRD_WDT_CTRL);
 167         sprd_wdt_lock(wdt->base);
 168         return 0;
 169 }
 170
 171 static void sprd_wdt_disable(void *_data)
 172 {
 173         struct sprd_wdt *wdt = _data;
 174
 175         sprd_wdt_unlock(wdt->base);
 176         writel_relaxed(0x0, wdt->base + SPRD_WDT_CTRL);
 177         sprd_wdt_lock(wdt->base);
 178
 179         clk_disable_unprepare(wdt->rtc_enable);
 180         clk_disable_unprepare(wdt->enable);
 181 }
 182
 183 static int sprd_wdt_start(struct watchdog_device *wdd)
 184 {
 185         struct sprd_wdt *wdt = to_sprd_wdt(wdd);
 186         u32 val;
 187         int ret;
 188
 189         ret = sprd_wdt_load_value(wdt, wdd->timeout, wdd->pretimeout);
 190         if (ret)
 191                 return ret;
 192
 193         sprd_wdt_unlock(wdt->base);
 194         val = readl_relaxed(wdt->base + SPRD_WDT_CTRL);
 195         val |= SPRD_WDT_CNT_EN_BIT | SPRD_WDT_INT_EN_BIT | SPRD_WDT_RST_EN_BIT;
 196         writel_relaxed(val, wdt->base + SPRD_WDT_CTRL);
 197         sprd_wdt_lock(wdt->base);
 198         set_bit(WDOG_HW_RUNNING, &wdd->status);
 199
 200         return 0;
 201 }
 202
 203 static int sprd_wdt_stop(struct watchdog_device *wdd)
 204 {
 205         struct sprd_wdt *wdt = to_sprd_wdt(wdd);
 206         u32 val;
 207
 208         sprd_wdt_unlock(wdt->base);
 209         val = readl_relaxed(wdt->base + SPRD_WDT_CTRL);
 210         val &= ~(SPRD_WDT_CNT_EN_BIT | SPRD_WDT_RST_EN_BIT |
 211                 SPRD_WDT_INT_EN_BIT);
 212         writel_relaxed(val, wdt->base + SPRD_WDT_CTRL);
 213         sprd_wdt_lock(wdt->base);
 214         return 0;
 215 }
 216
 217 static int sprd_wdt_set_timeout(struct watchdog_device *wdd,
 218                                 u32 timeout)
 219 {
 220         struct sprd_wdt *wdt = to_sprd_wdt(wdd);
 221
 222         if (timeout == wdd->timeout)
 223                 return 0;
 224
 225         wdd->timeout = timeout;
 226
 227         return sprd_wdt_load_value(wdt, timeout, wdd->pretimeout);
 228 }
 229
 230 static int sprd_wdt_set_pretimeout(struct watchdog_device *wdd,
 231                                    u32 new_pretimeout)
 232 {
 233         struct sprd_wdt *wdt = to_sprd_wdt(wdd);
 234
 235         if (new_pretimeout < wdd->min_timeout)
 236                 return -EINVAL;
 237
 238         wdd->pretimeout = new_pretimeout;
 239
 240         return sprd_wdt_load_value(wdt, wdd->timeout, new_pretimeout);
 241 }
 242
 243 static u32 sprd_wdt_get_timeleft(struct watchdog_device *wdd)
 244 {
 245         struct sprd_wdt *wdt = to_sprd_wdt(wdd);
 246         u32 val;
 247
 248         val = sprd_wdt_get_cnt_value(wdt);
 249         val = val / SPRD_WDT_CNT_STEP;
 250
 251         return val;
 252 }
 253
 254 static const struct watchdog_ops sprd_wdt_ops = {
 255         .owner = THIS_MODULE,
 256         .start = sprd_wdt_start,
 257         .stop = sprd_wdt_stop,
 258         .set_timeout = sprd_wdt_set_timeout,
 259         .set_pretimeout = sprd_wdt_set_pretimeout,
 260         .get_timeleft = sprd_wdt_get_timeleft,
 261 };
 262
 263 static const struct watchdog_info sprd_wdt_info = {
 264         .options = WDIOF_SETTIMEOUT |
 265                    WDIOF_PRETIMEOUT |
 266                    WDIOF_MAGICCLOSE |
 267                    WDIOF_KEEPALIVEPING,
 268         .identity = "Spreadtrum Watchdog Timer",
 269 };
 270
 271 static int sprd_wdt_probe(struct platform_device *pdev)
 272 {
 273         struct resource *wdt_res;
 274         struct sprd_wdt *wdt;
 275         int ret;
 276
 277         wdt = devm_kzalloc(&pdev->dev, sizeof(*wdt), GFP_KERNEL);
 278         if (!wdt)
 279                 return -ENOMEM;
 280
 281         wdt_res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 282         wdt->base = devm_ioremap_resource(&pdev->dev, wdt_res);
 283         if (IS_ERR(wdt->base))
 284                 return PTR_ERR(wdt->base);
 285
 286         wdt->enable = devm_clk_get(&pdev->dev, "enable");
 287         if (IS_ERR(wdt->enable)) {
 288                 dev_err(&pdev->dev, "can't get the enable clock\n");
 289                 return PTR_ERR(wdt->enable);
 290         }
 291
 292         wdt->rtc_enable = devm_clk_get(&pdev->dev, "rtc_enable");
 293         if (IS_ERR(wdt->rtc_enable)) {
 294                 dev_err(&pdev->dev, "can't get the rtc enable clock\n");
 295                 return PTR_ERR(wdt->rtc_enable);
 296         }
 297
 298         wdt->irq = platform_get_irq(pdev, 0);
 299         if (wdt->irq < 0) {
 300                 dev_err(&pdev->dev, "failed to get IRQ resource\n");
 301                 return wdt->irq;
 302         }
 303
 304         ret = devm_request_irq(&pdev->dev, wdt->irq, sprd_wdt_isr,
 305                                IRQF_NO_SUSPEND, "sprd-wdt", (void *)wdt);
 306         if (ret) {
 307                 dev_err(&pdev->dev, "failed to register irq\n");
 308                 return ret;
 309         }
 310
 311         wdt->wdd.info = &sprd_wdt_info;
 312         wdt->wdd.ops = &sprd_wdt_ops;
 313         wdt->wdd.parent = &pdev->dev;
 314         wdt->wdd.min_timeout = SPRD_WDT_MIN_TIMEOUT;
 315         wdt->wdd.max_timeout = SPRD_WDT_MAX_TIMEOUT;
 316         wdt->wdd.timeout = SPRD_WDT_MAX_TIMEOUT;
 317
 318         ret = sprd_wdt_enable(wdt);
 319         if (ret) {
 320                 dev_err(&pdev->dev, "failed to enable wdt\n");
 321                 return ret;
 322         }
 323         ret = devm_add_action(&pdev->dev, sprd_wdt_disable, wdt);
 324         if (ret) {
 325                 sprd_wdt_disable(wdt);
 326                 dev_err(&pdev->dev, "Failed to add wdt disable action\n");
 327                 return ret;
 328         }
 329
 330         watchdog_set_nowayout(&wdt->wdd, WATCHDOG_NOWAYOUT);
 331         watchdog_init_timeout(&wdt->wdd, 0, &pdev->dev);
 332
 333         ret = devm_watchdog_register_device(&pdev->dev, &wdt->wdd);
 334         if (ret) {
 335                 sprd_wdt_disable(wdt);
 336                 dev_err(&pdev->dev, "failed to register watchdog\n");
 337                 return ret;
 338         }
 339         platform_set_drvdata(pdev, wdt);
 340
 341         return 0;
 342 }
 343
 344 static int __maybe_unused sprd_wdt_pm_suspend(struct device *dev)
 345 {
 346         struct sprd_wdt *wdt = dev_get_drvdata(dev);
 347
 348         if (watchdog_active(&wdt->wdd))
 349                 sprd_wdt_stop(&wdt->wdd);
 350         sprd_wdt_disable(wdt);
 351
 352         return 0;
 353 }
 354
 355 static int __maybe_unused sprd_wdt_pm_resume(struct device *dev)
 356 {
 357         struct sprd_wdt *wdt = dev_get_drvdata(dev);
 358         int ret;
 359
 360         ret = sprd_wdt_enable(wdt);
 361         if (ret)
 362                 return ret;
 363
 364         if (watchdog_active(&wdt->wdd))
 365                 ret = sprd_wdt_start(&wdt->wdd);
 366
 367         return ret;
 368 }
 369
 370 static const struct dev_pm_ops sprd_wdt_pm_ops = {
 371         SET_SYSTEM_SLEEP_PM_OPS(sprd_wdt_pm_suspend,
 372                                 sprd_wdt_pm_resume)
 373 };
 374
 375 static const struct of_device_id sprd_wdt_match_table[] = {
 376         { .compatible = "sprd,sp9860-wdt", },
 377         {},
 378 };
 379 MODULE_DEVICE_TABLE(of, sprd_wdt_match_table);
 380
 381 static struct platform_driver sprd_watchdog_driver = {
 382         .probe  = sprd_wdt_probe,
 383         .driver = {
 384                 .name = "sprd-wdt",
 385                 .of_match_table = sprd_wdt_match_table,
 386                 .pm = &sprd_wdt_pm_ops,
 387         },
 388 };
 389 module_platform_driver(sprd_watchdog_driver);
 390
 391 MODULE_AUTHOR("Eric Long <eric.long@spreadtrum.com>");
 392 MODULE_DESCRIPTION("Spreadtrum Watchdog Timer Controller Driver");
 393 MODULE_LICENSE("GPL v2");