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_CMD32EN         BIT(13)
  18 #define WDOG_CS_ULK             BIT(11)
  19 #define WDOG_CS_RCS             BIT(10)
  20 #define LPO_CLK                 0x1
  21 #define LPO_CLK_SHIFT           8
  22 #define WDOG_CS_CLK             (LPO_CLK << LPO_CLK_SHIFT)
  23 #define WDOG_CS_EN              BIT(7)
  24 #define WDOG_CS_UPDATE          BIT(5)
  25 #define WDOG_CS_WAIT            BIT(1)
  26 #define WDOG_CS_STOP            BIT(0)
  27
  28 #define WDOG_CNT        0x4
  29 #define WDOG_TOVAL      0x8
  30
  31 #define REFRESH_SEQ0    0xA602
  32 #define REFRESH_SEQ1    0xB480
  33 #define REFRESH         ((REFRESH_SEQ1 << 16) | REFRESH_SEQ0)
  34
  35 #define UNLOCK_SEQ0     0xC520
  36 #define UNLOCK_SEQ1     0xD928
  37 #define UNLOCK          ((UNLOCK_SEQ1 << 16) | UNLOCK_SEQ0)
  38
  39 #define DEFAULT_TIMEOUT 60
  40 #define MAX_TIMEOUT     128
  41 #define WDOG_CLOCK_RATE 1000
  42 #define WDOG_WAIT_TIMEOUT       20
  43
  44 static bool nowayout = WATCHDOG_NOWAYOUT;
  45 module_param(nowayout, bool, 0000);
  46 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
  47                  __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
  48
  49 struct imx7ulp_wdt_device {
  50         struct watchdog_device wdd;
  51         void __iomem *base;
  52         struct clk *clk;
  53 };
  54
  55 static int imx7ulp_wdt_wait(void __iomem *base, u32 mask)
  56 {
  57         u32 val = readl(base + WDOG_CS);
  58
  59         if (!(val & mask) && readl_poll_timeout_atomic(base + WDOG_CS, val,
  60                                                        val & mask, 0,
  61                                                        WDOG_WAIT_TIMEOUT))
  62                 return -ETIMEDOUT;
  63
  64         return 0;
  65 }
  66
  67 static int imx7ulp_wdt_enable(struct watchdog_device *wdog, bool enable)
  68 {
  69         struct imx7ulp_wdt_device *wdt = watchdog_get_drvdata(wdog);
  70
  71         u32 val = readl(wdt->base + WDOG_CS);
  72         int ret;
  73
  74         local_irq_disable();
  75         writel(UNLOCK, wdt->base + WDOG_CNT);
  76         ret = imx7ulp_wdt_wait(wdt->base, WDOG_CS_ULK);
  77         if (ret)
  78                 goto enable_out;
  79         if (enable)
  80                 writel(val | WDOG_CS_EN, wdt->base + WDOG_CS);
  81         else
  82                 writel(val & ~WDOG_CS_EN, wdt->base + WDOG_CS);
  83         imx7ulp_wdt_wait(wdt->base, WDOG_CS_RCS);
  84
  85 enable_out:
  86         local_irq_enable();
  87
  88         return ret;
  89 }
  90
  91 static bool imx7ulp_wdt_is_enabled(void __iomem *base)
  92 {
  93         u32 val = readl(base + WDOG_CS);
  94
  95         return val & WDOG_CS_EN;
  96 }
  97
  98 static int imx7ulp_wdt_ping(struct watchdog_device *wdog)
  99 {
 100         struct imx7ulp_wdt_device *wdt = watchdog_get_drvdata(wdog);
 101
 102         writel(REFRESH, wdt->base + WDOG_CNT);
 103
 104         return 0;
 105 }
 106
 107 static int imx7ulp_wdt_start(struct watchdog_device *wdog)
 108 {
 109         return imx7ulp_wdt_enable(wdog, true);
 110 }
 111
 112 static int imx7ulp_wdt_stop(struct watchdog_device *wdog)
 113 {
 114         return imx7ulp_wdt_enable(wdog, false);
 115 }
 116
 117 static int imx7ulp_wdt_set_timeout(struct watchdog_device *wdog,
 118                                    unsigned int timeout)
 119 {
 120         struct imx7ulp_wdt_device *wdt = watchdog_get_drvdata(wdog);
 121         u32 val = WDOG_CLOCK_RATE * timeout;
 122         int ret;
 123
 124         local_irq_disable();
 125         writel(UNLOCK, wdt->base + WDOG_CNT);
 126         ret = imx7ulp_wdt_wait(wdt->base, WDOG_CS_ULK);
 127         if (ret)
 128                 goto timeout_out;
 129         writel(val, wdt->base + WDOG_TOVAL);
 130         imx7ulp_wdt_wait(wdt->base, WDOG_CS_RCS);
 131
 132         wdog->timeout = timeout;
 133
 134 timeout_out:
 135         local_irq_enable();
 136
 137         return ret;
 138 }
 139
 140 static int imx7ulp_wdt_restart(struct watchdog_device *wdog,
 141                                unsigned long action, void *data)
 142 {
 143         struct imx7ulp_wdt_device *wdt = watchdog_get_drvdata(wdog);
 144         int ret;
 145
 146         ret = imx7ulp_wdt_enable(wdog, true);
 147         if (ret)
 148                 return ret;
 149
 150         ret = imx7ulp_wdt_set_timeout(&wdt->wdd, 1);
 151         if (ret)
 152                 return ret;
 153
 154         /* wait for wdog to fire */
 155         while (true)
 156                 ;
 157
 158         return NOTIFY_DONE;
 159 }
 160
 161 static const struct watchdog_ops imx7ulp_wdt_ops = {
 162         .owner = THIS_MODULE,
 163         .start = imx7ulp_wdt_start,
 164         .stop  = imx7ulp_wdt_stop,
 165         .ping  = imx7ulp_wdt_ping,
 166         .set_timeout = imx7ulp_wdt_set_timeout,
 167         .restart = imx7ulp_wdt_restart,
 168 };
 169
 170 static const struct watchdog_info imx7ulp_wdt_info = {
 171         .identity = "i.MX7ULP watchdog timer",
 172         .options  = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING |
 173                     WDIOF_MAGICCLOSE,
 174 };
 175
 176 static int imx7ulp_wdt_init(void __iomem *base, unsigned int timeout)
 177 {
 178         u32 val;
 179         int ret;
 180
 181         local_irq_disable();
 182         /* unlock the wdog for reconfiguration */
 183         writel_relaxed(UNLOCK_SEQ0, base + WDOG_CNT);
 184         writel_relaxed(UNLOCK_SEQ1, base + WDOG_CNT);
 185         ret = imx7ulp_wdt_wait(base, WDOG_CS_ULK);
 186         if (ret)
 187                 goto init_out;
 188
 189         /* set an initial timeout value in TOVAL */
 190         writel(timeout, base + WDOG_TOVAL);
 191         /* enable 32bit command sequence and reconfigure */
 192         val = WDOG_CS_CMD32EN | WDOG_CS_CLK | WDOG_CS_UPDATE |
 193               WDOG_CS_WAIT | WDOG_CS_STOP;
 194         writel(val, base + WDOG_CS);
 195         imx7ulp_wdt_wait(base, WDOG_CS_RCS);
 196
 197 init_out:
 198         local_irq_enable();
 199
 200         return ret;
 201 }
 202
 203 static void imx7ulp_wdt_action(void *data)
 204 {
 205         clk_disable_unprepare(data);
 206 }
 207
 208 static int imx7ulp_wdt_probe(struct platform_device *pdev)
 209 {
 210         struct imx7ulp_wdt_device *imx7ulp_wdt;
 211         struct device *dev = &pdev->dev;
 212         struct watchdog_device *wdog;
 213         int ret;
 214
 215         imx7ulp_wdt = devm_kzalloc(dev, sizeof(*imx7ulp_wdt), GFP_KERNEL);
 216         if (!imx7ulp_wdt)
 217                 return -ENOMEM;
 218
 219         platform_set_drvdata(pdev, imx7ulp_wdt);
 220
 221         imx7ulp_wdt->base = devm_platform_ioremap_resource(pdev, 0);
 222         if (IS_ERR(imx7ulp_wdt->base))
 223                 return PTR_ERR(imx7ulp_wdt->base);
 224
 225         imx7ulp_wdt->clk = devm_clk_get(dev, NULL);
 226         if (IS_ERR(imx7ulp_wdt->clk)) {
 227                 dev_err(dev, "Failed to get watchdog clock\n");
 228                 return PTR_ERR(imx7ulp_wdt->clk);
 229         }
 230
 231         ret = clk_prepare_enable(imx7ulp_wdt->clk);
 232         if (ret)
 233                 return ret;
 234
 235         ret = devm_add_action_or_reset(dev, imx7ulp_wdt_action, imx7ulp_wdt->clk);
 236         if (ret)
 237                 return ret;
 238
 239         wdog = &imx7ulp_wdt->wdd;
 240         wdog->info = &imx7ulp_wdt_info;
 241         wdog->ops = &imx7ulp_wdt_ops;
 242         wdog->min_timeout = 1;
 243         wdog->max_timeout = MAX_TIMEOUT;
 244         wdog->parent = dev;
 245         wdog->timeout = DEFAULT_TIMEOUT;
 246
 247         watchdog_init_timeout(wdog, 0, dev);
 248         watchdog_stop_on_reboot(wdog);
 249         watchdog_stop_on_unregister(wdog);
 250         watchdog_set_drvdata(wdog, imx7ulp_wdt);
 251         ret = imx7ulp_wdt_init(imx7ulp_wdt->base, wdog->timeout * WDOG_CLOCK_RATE);
 252         if (ret)
 253                 return ret;
 254
 255         return devm_watchdog_register_device(dev, wdog);
 256 }
 257
 258 static int __maybe_unused imx7ulp_wdt_suspend(struct device *dev)
 259 {
 260         struct imx7ulp_wdt_device *imx7ulp_wdt = dev_get_drvdata(dev);
 261
 262         if (watchdog_active(&imx7ulp_wdt->wdd))
 263                 imx7ulp_wdt_stop(&imx7ulp_wdt->wdd);
 264
 265         clk_disable_unprepare(imx7ulp_wdt->clk);
 266
 267         return 0;
 268 }
 269
 270 static int __maybe_unused imx7ulp_wdt_resume(struct device *dev)
 271 {
 272         struct imx7ulp_wdt_device *imx7ulp_wdt = dev_get_drvdata(dev);
 273         u32 timeout = imx7ulp_wdt->wdd.timeout * WDOG_CLOCK_RATE;
 274         int ret;
 275
 276         ret = clk_prepare_enable(imx7ulp_wdt->clk);
 277         if (ret)
 278                 return ret;
 279
 280         if (imx7ulp_wdt_is_enabled(imx7ulp_wdt->base))
 281                 imx7ulp_wdt_init(imx7ulp_wdt->base, timeout);
 282
 283         if (watchdog_active(&imx7ulp_wdt->wdd))
 284                 imx7ulp_wdt_start(&imx7ulp_wdt->wdd);
 285
 286         return 0;
 287 }
 288
 289 static SIMPLE_DEV_PM_OPS(imx7ulp_wdt_pm_ops, imx7ulp_wdt_suspend,
 290                          imx7ulp_wdt_resume);
 291
 292 static const struct of_device_id imx7ulp_wdt_dt_ids[] = {
 293         { .compatible = "fsl,imx7ulp-wdt", },
 294         { /* sentinel */ }
 295 };
 296 MODULE_DEVICE_TABLE(of, imx7ulp_wdt_dt_ids);
 297
 298 static struct platform_driver imx7ulp_wdt_driver = {
 299         .probe          = imx7ulp_wdt_probe,
 300         .driver         = {
 301                 .name   = "imx7ulp-wdt",
 302                 .pm     = &imx7ulp_wdt_pm_ops,
 303                 .of_match_table = imx7ulp_wdt_dt_ids,
 304         },
 305 };
 306 module_platform_driver(imx7ulp_wdt_driver);
 307
 308 MODULE_AUTHOR("Anson Huang <Anson.Huang@nxp.com>");
 309 MODULE_DESCRIPTION("Freescale i.MX7ULP watchdog driver");
 310 MODULE_LICENSE("GPL v2");