drivers/watchdog/qcom-wdt.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /* Copyright (c) 2014, The Linux Foundation. All rights reserved.
   3  */
   4 #include <linux/bits.h>
   5 #include <linux/clk.h>
   6 #include <linux/delay.h>
   7 #include <linux/interrupt.h>
   8 #include <linux/io.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/watchdog.h>
  14
  15 enum wdt_reg {
  16         WDT_RST,
  17         WDT_EN,
  18         WDT_STS,
  19         WDT_BARK_TIME,
  20         WDT_BITE_TIME,
  21 };
  22
  23 #define QCOM_WDT_ENABLE         BIT(0)
  24
  25 static const u32 reg_offset_data_apcs_tmr[] = {
  26         [WDT_RST] = 0x38,
  27         [WDT_EN] = 0x40,
  28         [WDT_STS] = 0x44,
  29         [WDT_BARK_TIME] = 0x4C,
  30         [WDT_BITE_TIME] = 0x5C,
  31 };
  32
  33 static const u32 reg_offset_data_kpss[] = {
  34         [WDT_RST] = 0x4,
  35         [WDT_EN] = 0x8,
  36         [WDT_STS] = 0xC,
  37         [WDT_BARK_TIME] = 0x10,
  38         [WDT_BITE_TIME] = 0x14,
  39 };
  40
  41 struct qcom_wdt_match_data {
  42         const u32 *offset;
  43         bool pretimeout;
  44         u32 max_tick_count;
  45 };
  46
  47 struct qcom_wdt {
  48         struct watchdog_device  wdd;
  49         unsigned long           rate;
  50         void __iomem            *base;
  51         const u32               *layout;
  52 };
  53
  54 static void __iomem *wdt_addr(struct qcom_wdt *wdt, enum wdt_reg reg)
  55 {
  56         return wdt->base + wdt->layout[reg];
  57 }
  58
  59 static inline
  60 struct qcom_wdt *to_qcom_wdt(struct watchdog_device *wdd)
  61 {
  62         return container_of(wdd, struct qcom_wdt, wdd);
  63 }
  64
  65 static irqreturn_t qcom_wdt_isr(int irq, void *arg)
  66 {
  67         struct watchdog_device *wdd = arg;
  68
  69         watchdog_notify_pretimeout(wdd);
  70
  71         return IRQ_HANDLED;
  72 }
  73
  74 static int qcom_wdt_start(struct watchdog_device *wdd)
  75 {
  76         struct qcom_wdt *wdt = to_qcom_wdt(wdd);
  77         unsigned int bark = wdd->timeout - wdd->pretimeout;
  78
  79         writel(0, wdt_addr(wdt, WDT_EN));
  80         writel(1, wdt_addr(wdt, WDT_RST));
  81         writel(bark * wdt->rate, wdt_addr(wdt, WDT_BARK_TIME));
  82         writel(wdd->timeout * wdt->rate, wdt_addr(wdt, WDT_BITE_TIME));
  83         writel(QCOM_WDT_ENABLE, wdt_addr(wdt, WDT_EN));
  84         return 0;
  85 }
  86
  87 static int qcom_wdt_stop(struct watchdog_device *wdd)
  88 {
  89         struct qcom_wdt *wdt = to_qcom_wdt(wdd);
  90
  91         writel(0, wdt_addr(wdt, WDT_EN));
  92         return 0;
  93 }
  94
  95 static int qcom_wdt_ping(struct watchdog_device *wdd)
  96 {
  97         struct qcom_wdt *wdt = to_qcom_wdt(wdd);
  98
  99         writel(1, wdt_addr(wdt, WDT_RST));
 100         return 0;
 101 }
 102
 103 static int qcom_wdt_set_timeout(struct watchdog_device *wdd,
 104                                 unsigned int timeout)
 105 {
 106         wdd->timeout = timeout;
 107         return qcom_wdt_start(wdd);
 108 }
 109
 110 static int qcom_wdt_set_pretimeout(struct watchdog_device *wdd,
 111                                    unsigned int timeout)
 112 {
 113         wdd->pretimeout = timeout;
 114         return qcom_wdt_start(wdd);
 115 }
 116
 117 static int qcom_wdt_restart(struct watchdog_device *wdd, unsigned long action,
 118                             void *data)
 119 {
 120         struct qcom_wdt *wdt = to_qcom_wdt(wdd);
 121         u32 timeout;
 122
 123         /*
 124          * Trigger watchdog bite:
 125          *    Setup BITE_TIME to be 128ms, and enable WDT.
 126          */
 127         timeout = 128 * wdt->rate / 1000;
 128
 129         writel(0, wdt_addr(wdt, WDT_EN));
 130         writel(1, wdt_addr(wdt, WDT_RST));
 131         writel(timeout, wdt_addr(wdt, WDT_BARK_TIME));
 132         writel(timeout, wdt_addr(wdt, WDT_BITE_TIME));
 133         writel(QCOM_WDT_ENABLE, wdt_addr(wdt, WDT_EN));
 134
 135         /*
 136          * Actually make sure the above sequence hits hardware before sleeping.
 137          */
 138         wmb();
 139
 140         mdelay(150);
 141         return 0;
 142 }
 143
 144 static int qcom_wdt_is_running(struct watchdog_device *wdd)
 145 {
 146         struct qcom_wdt *wdt = to_qcom_wdt(wdd);
 147
 148         return (readl(wdt_addr(wdt, WDT_EN)) & QCOM_WDT_ENABLE);
 149 }
 150
 151 static const struct watchdog_ops qcom_wdt_ops = {
 152         .start          = qcom_wdt_start,
 153         .stop           = qcom_wdt_stop,
 154         .ping           = qcom_wdt_ping,
 155         .set_timeout    = qcom_wdt_set_timeout,
 156         .set_pretimeout = qcom_wdt_set_pretimeout,
 157         .restart        = qcom_wdt_restart,
 158         .owner          = THIS_MODULE,
 159 };
 160
 161 static const struct watchdog_info qcom_wdt_info = {
 162         .options        = WDIOF_KEEPALIVEPING
 163                         | WDIOF_MAGICCLOSE
 164                         | WDIOF_SETTIMEOUT
 165                         | WDIOF_CARDRESET,
 166         .identity       = KBUILD_MODNAME,
 167 };
 168
 169 static const struct watchdog_info qcom_wdt_pt_info = {
 170         .options        = WDIOF_KEEPALIVEPING
 171                         | WDIOF_MAGICCLOSE
 172                         | WDIOF_SETTIMEOUT
 173                         | WDIOF_PRETIMEOUT
 174                         | WDIOF_CARDRESET,
 175         .identity       = KBUILD_MODNAME,
 176 };
 177
 178 static const struct qcom_wdt_match_data match_data_apcs_tmr = {
 179         .offset = reg_offset_data_apcs_tmr,
 180         .pretimeout = false,
 181         .max_tick_count = 0x10000000U,
 182 };
 183
 184 static const struct qcom_wdt_match_data match_data_kpss = {
 185         .offset = reg_offset_data_kpss,
 186         .pretimeout = true,
 187         .max_tick_count = 0xFFFFFU,
 188 };
 189
 190 static int qcom_wdt_probe(struct platform_device *pdev)
 191 {
 192         struct device *dev = &pdev->dev;
 193         struct qcom_wdt *wdt;
 194         struct resource *res;
 195         struct device_node *np = dev->of_node;
 196         const struct qcom_wdt_match_data *data;
 197         u32 percpu_offset;
 198         int irq, ret;
 199         struct clk *clk;
 200
 201         data = of_device_get_match_data(dev);
 202         if (!data) {
 203                 dev_err(dev, "Unsupported QCOM WDT module\n");
 204                 return -ENODEV;
 205         }
 206
 207         wdt = devm_kzalloc(dev, sizeof(*wdt), GFP_KERNEL);
 208         if (!wdt)
 209                 return -ENOMEM;
 210
 211         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 212         if (!res)
 213                 return -ENOMEM;
 214
 215         /* We use CPU0's DGT for the watchdog */
 216         if (of_property_read_u32(np, "cpu-offset", &percpu_offset))
 217                 percpu_offset = 0;
 218
 219         res->start += percpu_offset;
 220         res->end += percpu_offset;
 221
 222         wdt->base = devm_ioremap_resource(dev, res);
 223         if (IS_ERR(wdt->base))
 224                 return PTR_ERR(wdt->base);
 225
 226         clk = devm_clk_get_enabled(dev, NULL);
 227         if (IS_ERR(clk)) {
 228                 dev_err(dev, "failed to get input clock\n");
 229                 return PTR_ERR(clk);
 230         }
 231
 232         /*
 233          * We use the clock rate to calculate the max timeout, so ensure it's
 234          * not zero to avoid a divide-by-zero exception.
 235          *
 236          * WATCHDOG_CORE assumes units of seconds, if the WDT is clocked such
 237          * that it would bite before a second elapses it's usefulness is
 238          * limited.  Bail if this is the case.
 239          */
 240         wdt->rate = clk_get_rate(clk);
 241         if (wdt->rate == 0 ||
 242             wdt->rate > data->max_tick_count) {
 243                 dev_err(dev, "invalid clock rate\n");
 244                 return -EINVAL;
 245         }
 246
 247         /* check if there is pretimeout support */
 248         irq = platform_get_irq_optional(pdev, 0);
 249         if (data->pretimeout && irq > 0) {
 250                 ret = devm_request_irq(dev, irq, qcom_wdt_isr, 0,
 251                                        "wdt_bark", &wdt->wdd);
 252                 if (ret)
 253                         return ret;
 254
 255                 wdt->wdd.info = &qcom_wdt_pt_info;
 256                 wdt->wdd.pretimeout = 1;
 257         } else {
 258                 if (irq == -EPROBE_DEFER)
 259                         return -EPROBE_DEFER;
 260
 261                 wdt->wdd.info = &qcom_wdt_info;
 262         }
 263
 264         wdt->wdd.ops = &qcom_wdt_ops;
 265         wdt->wdd.min_timeout = 1;
 266         wdt->wdd.max_timeout = data->max_tick_count / wdt->rate;
 267         wdt->wdd.parent = dev;
 268         wdt->layout = data->offset;
 269
 270         if (readl(wdt_addr(wdt, WDT_STS)) & 1)
 271                 wdt->wdd.bootstatus = WDIOF_CARDRESET;
 272
 273         /*
 274          * If 'timeout-sec' unspecified in devicetree, assume a 30 second
 275          * default, unless the max timeout is less than 30 seconds, then use
 276          * the max instead.
 277          */
 278         wdt->wdd.timeout = min(wdt->wdd.max_timeout, 30U);
 279         watchdog_init_timeout(&wdt->wdd, 0, dev);
 280
 281         /*
 282          * If WDT is already running, call WDT start which
 283          * will stop the WDT, set timeouts as bootloader
 284          * might use different ones and set running bit
 285          * to inform the WDT subsystem to ping the WDT
 286          */
 287         if (qcom_wdt_is_running(&wdt->wdd)) {
 288                 qcom_wdt_start(&wdt->wdd);
 289                 set_bit(WDOG_HW_RUNNING, &wdt->wdd.status);
 290         }
 291
 292         ret = devm_watchdog_register_device(dev, &wdt->wdd);
 293         if (ret)
 294                 return ret;
 295
 296         platform_set_drvdata(pdev, wdt);
 297         return 0;
 298 }
 299
 300 static int __maybe_unused qcom_wdt_suspend(struct device *dev)
 301 {
 302         struct qcom_wdt *wdt = dev_get_drvdata(dev);
 303
 304         if (watchdog_active(&wdt->wdd))
 305                 qcom_wdt_stop(&wdt->wdd);
 306
 307         return 0;
 308 }
 309
 310 static int __maybe_unused qcom_wdt_resume(struct device *dev)
 311 {
 312         struct qcom_wdt *wdt = dev_get_drvdata(dev);
 313
 314         if (watchdog_active(&wdt->wdd))
 315                 qcom_wdt_start(&wdt->wdd);
 316
 317         return 0;
 318 }
 319
 320 static const struct dev_pm_ops qcom_wdt_pm_ops = {
 321         SET_LATE_SYSTEM_SLEEP_PM_OPS(qcom_wdt_suspend, qcom_wdt_resume)
 322 };
 323
 324 static const struct of_device_id qcom_wdt_of_table[] = {
 325         { .compatible = "qcom,kpss-timer", .data = &match_data_apcs_tmr },
 326         { .compatible = "qcom,scss-timer", .data = &match_data_apcs_tmr },
 327         { .compatible = "qcom,kpss-wdt", .data = &match_data_kpss },
 328         { },
 329 };
 330 MODULE_DEVICE_TABLE(of, qcom_wdt_of_table);
 331
 332 static struct platform_driver qcom_watchdog_driver = {
 333         .probe  = qcom_wdt_probe,
 334         .driver = {
 335                 .name           = KBUILD_MODNAME,
 336                 .of_match_table = qcom_wdt_of_table,
 337                 .pm             = &qcom_wdt_pm_ops,
 338         },
 339 };
 340 module_platform_driver(qcom_watchdog_driver);
 341
 342 MODULE_DESCRIPTION("QCOM KPSS Watchdog Driver");
 343 MODULE_LICENSE("GPL v2");