drivers/watchdog/keembay_wdt.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Watchdog driver for Intel Keem Bay non-secure watchdog.
   4  *
   5  * Copyright (C) 2020 Intel Corporation
   6  */
   7
   8 #include <linux/arm-smccc.h>
   9 #include <linux/bits.h>
  10 #include <linux/clk.h>
  11 #include <linux/interrupt.h>
  12 #include <linux/io.h>
  13 #include <linux/limits.h>
  14 #include <linux/module.h>
  15 #include <linux/mod_devicetable.h>
  16 #include <linux/platform_device.h>
  17 #include <linux/reboot.h>
  18 #include <linux/watchdog.h>
  19
  20 /* Non-secure watchdog register offsets */
  21 #define TIM_WATCHDOG            0x0
  22 #define TIM_WATCHDOG_INT_THRES  0x4
  23 #define TIM_WDOG_EN             0x8
  24 #define TIM_SAFE                0xc
  25
  26 #define WDT_TH_INT_MASK         BIT(8)
  27 #define WDT_TO_INT_MASK         BIT(9)
  28 #define WDT_INT_CLEAR_SMC       0x8200ff18
  29
  30 #define WDT_UNLOCK              0xf1d0dead
  31 #define WDT_DISABLE             0x0
  32 #define WDT_ENABLE              0x1
  33
  34 #define WDT_LOAD_MAX            U32_MAX
  35 #define WDT_LOAD_MIN            1
  36
  37 #define WDT_TIMEOUT             5
  38 #define WDT_PRETIMEOUT          4
  39
  40 static unsigned int timeout = WDT_TIMEOUT;
  41 module_param(timeout, int, 0);
  42 MODULE_PARM_DESC(timeout, "Watchdog timeout period in seconds (default = "
  43                  __MODULE_STRING(WDT_TIMEOUT) ")");
  44
  45 static bool nowayout = WATCHDOG_NOWAYOUT;
  46 module_param(nowayout, bool, 0);
  47 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default = "
  48                  __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
  49
  50 struct keembay_wdt {
  51         struct watchdog_device  wdd;
  52         struct clk              *clk;
  53         unsigned int            rate;
  54         int                     to_irq;
  55         int                     th_irq;
  56         void __iomem            *base;
  57 };
  58
  59 static inline u32 keembay_wdt_readl(struct keembay_wdt *wdt, u32 offset)
  60 {
  61         return readl(wdt->base + offset);
  62 }
  63
  64 static inline void keembay_wdt_writel(struct keembay_wdt *wdt, u32 offset, u32 val)
  65 {
  66         writel(WDT_UNLOCK, wdt->base + TIM_SAFE);
  67         writel(val, wdt->base + offset);
  68 }
  69
  70 static void keembay_wdt_set_timeout_reg(struct watchdog_device *wdog)
  71 {
  72         struct keembay_wdt *wdt = watchdog_get_drvdata(wdog);
  73
  74         keembay_wdt_writel(wdt, TIM_WATCHDOG, wdog->timeout * wdt->rate);
  75 }
  76
  77 static void keembay_wdt_set_pretimeout_reg(struct watchdog_device *wdog)
  78 {
  79         struct keembay_wdt *wdt = watchdog_get_drvdata(wdog);
  80         u32 th_val = 0;
  81
  82         if (wdog->pretimeout)
  83                 th_val = wdog->timeout - wdog->pretimeout;
  84
  85         keembay_wdt_writel(wdt, TIM_WATCHDOG_INT_THRES, th_val * wdt->rate);
  86 }
  87
  88 static int keembay_wdt_start(struct watchdog_device *wdog)
  89 {
  90         struct keembay_wdt *wdt = watchdog_get_drvdata(wdog);
  91
  92         keembay_wdt_writel(wdt, TIM_WDOG_EN, WDT_ENABLE);
  93
  94         return 0;
  95 }
  96
  97 static int keembay_wdt_stop(struct watchdog_device *wdog)
  98 {
  99         struct keembay_wdt *wdt = watchdog_get_drvdata(wdog);
 100
 101         keembay_wdt_writel(wdt, TIM_WDOG_EN, WDT_DISABLE);
 102
 103         return 0;
 104 }
 105
 106 static int keembay_wdt_ping(struct watchdog_device *wdog)
 107 {
 108         keembay_wdt_set_timeout_reg(wdog);
 109
 110         return 0;
 111 }
 112
 113 static int keembay_wdt_set_timeout(struct watchdog_device *wdog, u32 t)
 114 {
 115         wdog->timeout = t;
 116         keembay_wdt_set_timeout_reg(wdog);
 117         keembay_wdt_set_pretimeout_reg(wdog);
 118
 119         return 0;
 120 }
 121
 122 static int keembay_wdt_set_pretimeout(struct watchdog_device *wdog, u32 t)
 123 {
 124         if (t > wdog->timeout)
 125                 return -EINVAL;
 126
 127         wdog->pretimeout = t;
 128         keembay_wdt_set_pretimeout_reg(wdog);
 129
 130         return 0;
 131 }
 132
 133 static unsigned int keembay_wdt_get_timeleft(struct watchdog_device *wdog)
 134 {
 135         struct keembay_wdt *wdt = watchdog_get_drvdata(wdog);
 136
 137         return keembay_wdt_readl(wdt, TIM_WATCHDOG) / wdt->rate;
 138 }
 139
 140 /*
 141  * SMC call is used to clear the interrupt bits, because the TIM_GEN_CONFIG
 142  * register is in the secure bank.
 143  */
 144 static irqreturn_t keembay_wdt_to_isr(int irq, void *dev_id)
 145 {
 146         struct keembay_wdt *wdt = dev_id;
 147         struct arm_smccc_res res;
 148
 149         arm_smccc_smc(WDT_INT_CLEAR_SMC, WDT_TO_INT_MASK, 0, 0, 0, 0, 0, 0, &res);
 150         dev_crit(wdt->wdd.parent, "Intel Keem Bay non-secure wdt timeout.\n");
 151         emergency_restart();
 152
 153         return IRQ_HANDLED;
 154 }
 155
 156 static irqreturn_t keembay_wdt_th_isr(int irq, void *dev_id)
 157 {
 158         struct keembay_wdt *wdt = dev_id;
 159         struct arm_smccc_res res;
 160
 161         keembay_wdt_set_pretimeout(&wdt->wdd, 0x0);
 162
 163         arm_smccc_smc(WDT_INT_CLEAR_SMC, WDT_TH_INT_MASK, 0, 0, 0, 0, 0, 0, &res);
 164         dev_crit(wdt->wdd.parent, "Intel Keem Bay non-secure wdt pre-timeout.\n");
 165         watchdog_notify_pretimeout(&wdt->wdd);
 166
 167         return IRQ_HANDLED;
 168 }
 169
 170 static const struct watchdog_info keembay_wdt_info = {
 171         .identity       = "Intel Keem Bay Watchdog Timer",
 172         .options        = WDIOF_SETTIMEOUT |
 173                           WDIOF_PRETIMEOUT |
 174                           WDIOF_MAGICCLOSE |
 175                           WDIOF_KEEPALIVEPING,
 176 };
 177
 178 static const struct watchdog_ops keembay_wdt_ops = {
 179         .owner          = THIS_MODULE,
 180         .start          = keembay_wdt_start,
 181         .stop           = keembay_wdt_stop,
 182         .ping           = keembay_wdt_ping,
 183         .set_timeout    = keembay_wdt_set_timeout,
 184         .set_pretimeout = keembay_wdt_set_pretimeout,
 185         .get_timeleft   = keembay_wdt_get_timeleft,
 186 };
 187
 188 static int keembay_wdt_probe(struct platform_device *pdev)
 189 {
 190         struct device *dev = &pdev->dev;
 191         struct keembay_wdt *wdt;
 192         int ret;
 193
 194         wdt = devm_kzalloc(dev, sizeof(*wdt), GFP_KERNEL);
 195         if (!wdt)
 196                 return -ENOMEM;
 197
 198         wdt->base = devm_platform_ioremap_resource(pdev, 0);
 199         if (IS_ERR(wdt->base))
 200                 return PTR_ERR(wdt->base);
 201
 202         /* we do not need to enable the clock as it is enabled by default */
 203         wdt->clk = devm_clk_get(dev, NULL);
 204         if (IS_ERR(wdt->clk))
 205                 return dev_err_probe(dev, PTR_ERR(wdt->clk), "Failed to get clock\n");
 206
 207         wdt->rate = clk_get_rate(wdt->clk);
 208         if (!wdt->rate)
 209                 return dev_err_probe(dev, -EINVAL, "Failed to get clock rate\n");
 210
 211         wdt->th_irq = platform_get_irq_byname(pdev, "threshold");
 212         if (wdt->th_irq < 0)
 213                 return dev_err_probe(dev, wdt->th_irq, "Failed to get IRQ for threshold\n");
 214
 215         ret = devm_request_irq(dev, wdt->th_irq, keembay_wdt_th_isr, 0,
 216                                "keembay-wdt", wdt);
 217         if (ret)
 218                 return dev_err_probe(dev, ret, "Failed to request IRQ for threshold\n");
 219
 220         wdt->to_irq = platform_get_irq_byname(pdev, "timeout");
 221         if (wdt->to_irq < 0)
 222                 return dev_err_probe(dev, wdt->to_irq, "Failed to get IRQ for timeout\n");
 223
 224         ret = devm_request_irq(dev, wdt->to_irq, keembay_wdt_to_isr, 0,
 225                                "keembay-wdt", wdt);
 226         if (ret)
 227                 return dev_err_probe(dev, ret, "Failed to request IRQ for timeout\n");
 228
 229         wdt->wdd.parent         = dev;
 230         wdt->wdd.info           = &keembay_wdt_info;
 231         wdt->wdd.ops            = &keembay_wdt_ops;
 232         wdt->wdd.min_timeout    = WDT_LOAD_MIN;
 233         wdt->wdd.max_timeout    = WDT_LOAD_MAX / wdt->rate;
 234         wdt->wdd.timeout        = WDT_TIMEOUT;
 235         wdt->wdd.pretimeout     = WDT_PRETIMEOUT;
 236
 237         watchdog_set_drvdata(&wdt->wdd, wdt);
 238         watchdog_set_nowayout(&wdt->wdd, nowayout);
 239         watchdog_init_timeout(&wdt->wdd, timeout, dev);
 240         keembay_wdt_set_timeout(&wdt->wdd, wdt->wdd.timeout);
 241         keembay_wdt_set_pretimeout(&wdt->wdd, wdt->wdd.pretimeout);
 242
 243         ret = devm_watchdog_register_device(dev, &wdt->wdd);
 244         if (ret)
 245                 return dev_err_probe(dev, ret, "Failed to register watchdog device.\n");
 246
 247         platform_set_drvdata(pdev, wdt);
 248         dev_info(dev, "Initial timeout %d sec%s.\n",
 249                  wdt->wdd.timeout, nowayout ? ", nowayout" : "");
 250
 251         return 0;
 252 }
 253
 254 static int __maybe_unused keembay_wdt_suspend(struct device *dev)
 255 {
 256         struct keembay_wdt *wdt = dev_get_drvdata(dev);
 257
 258         if (watchdog_active(&wdt->wdd))
 259                 return keembay_wdt_stop(&wdt->wdd);
 260
 261         return 0;
 262 }
 263
 264 static int __maybe_unused keembay_wdt_resume(struct device *dev)
 265 {
 266         struct keembay_wdt *wdt = dev_get_drvdata(dev);
 267
 268         if (watchdog_active(&wdt->wdd))
 269                 return keembay_wdt_start(&wdt->wdd);
 270
 271         return 0;
 272 }
 273
 274 static SIMPLE_DEV_PM_OPS(keembay_wdt_pm_ops, keembay_wdt_suspend,
 275                          keembay_wdt_resume);
 276
 277 static const struct of_device_id keembay_wdt_match[] = {
 278         { .compatible = "intel,keembay-wdt" },
 279         { }
 280 };
 281 MODULE_DEVICE_TABLE(of, keembay_wdt_match);
 282
 283 static struct platform_driver keembay_wdt_driver = {
 284         .probe  = keembay_wdt_probe,
 285         .driver = {
 286                 .name           = "keembay_wdt",
 287                 .of_match_table = keembay_wdt_match,
 288                 .pm             = &keembay_wdt_pm_ops,
 289         },
 290 };
 291
 292 module_platform_driver(keembay_wdt_driver);
 293
 294 MODULE_DESCRIPTION("Intel Keem Bay SoC watchdog driver");
 295 MODULE_AUTHOR("Wan Ahmad Zainie <wan.ahmad.zainie.wan.mohamad@intel.com");
 296 MODULE_LICENSE("GPL v2");