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"); 297