1 /* 2 * Watchdog driver for Faraday Technology FTWDT010 3 * 4 * Copyright (C) 2017 Linus Walleij <linus.walleij@linaro.org> 5 * 6 * Inspired by the out-of-tree drivers from OpenWRT: 7 * Copyright (C) 2009 Paulius Zaleckas <paulius.zaleckas@teltonika.lt> 8 * 9 * This program is free software; you can redistribute it and/or modify 10 * it under the terms of the GNU General Public License version 2 as 11 * published by the Free Software Foundation. 12 */ 13 14 #include <linux/bitops.h> 15 #include <linux/init.h> 16 #include <linux/interrupt.h> 17 #include <linux/io.h> 18 #include <linux/kernel.h> 19 #include <linux/module.h> 20 #include <linux/of_device.h> 21 #include <linux/platform_device.h> 22 #include <linux/slab.h> 23 #include <linux/watchdog.h> 24 25 #define FTWDT010_WDCOUNTER 0x0 26 #define FTWDT010_WDLOAD 0x4 27 #define FTWDT010_WDRESTART 0x8 28 #define FTWDT010_WDCR 0xC 29 30 #define WDRESTART_MAGIC 0x5AB9 31 32 #define WDCR_CLOCK_5MHZ BIT(4) 33 #define WDCR_WDEXT BIT(3) 34 #define WDCR_WDINTR BIT(2) 35 #define WDCR_SYS_RST BIT(1) 36 #define WDCR_ENABLE BIT(0) 37 38 #define WDT_CLOCK 5000000 /* 5 MHz */ 39 40 struct ftwdt010_wdt { 41 struct watchdog_device wdd; 42 struct device *dev; 43 void __iomem *base; 44 bool has_irq; 45 }; 46 47 static inline 48 struct ftwdt010_wdt *to_ftwdt010_wdt(struct watchdog_device *wdd) 49 { 50 return container_of(wdd, struct ftwdt010_wdt, wdd); 51 } 52 53 static int ftwdt010_wdt_start(struct watchdog_device *wdd) 54 { 55 struct ftwdt010_wdt *gwdt = to_ftwdt010_wdt(wdd); 56 u32 enable; 57 58 writel(wdd->timeout * WDT_CLOCK, gwdt->base + FTWDT010_WDLOAD); 59 writel(WDRESTART_MAGIC, gwdt->base + FTWDT010_WDRESTART); 60 /* set clock before enabling */ 61 enable = WDCR_CLOCK_5MHZ | WDCR_SYS_RST; 62 writel(enable, gwdt->base + FTWDT010_WDCR); 63 if (gwdt->has_irq) 64 enable |= WDCR_WDINTR; 65 enable |= WDCR_ENABLE; 66 writel(enable, gwdt->base + FTWDT010_WDCR); 67 68 return 0; 69 } 70 71 static int ftwdt010_wdt_stop(struct watchdog_device *wdd) 72 { 73 struct ftwdt010_wdt *gwdt = to_ftwdt010_wdt(wdd); 74 75 writel(0, gwdt->base + FTWDT010_WDCR); 76 77 return 0; 78 } 79 80 static int ftwdt010_wdt_ping(struct watchdog_device *wdd) 81 { 82 struct ftwdt010_wdt *gwdt = to_ftwdt010_wdt(wdd); 83 84 writel(WDRESTART_MAGIC, gwdt->base + FTWDT010_WDRESTART); 85 86 return 0; 87 } 88 89 static int ftwdt010_wdt_set_timeout(struct watchdog_device *wdd, 90 unsigned int timeout) 91 { 92 wdd->timeout = timeout; 93 if (watchdog_active(wdd)) 94 ftwdt010_wdt_start(wdd); 95 96 return 0; 97 } 98 99 static irqreturn_t ftwdt010_wdt_interrupt(int irq, void *data) 100 { 101 struct ftwdt010_wdt *gwdt = data; 102 103 watchdog_notify_pretimeout(&gwdt->wdd); 104 105 return IRQ_HANDLED; 106 } 107 108 static const struct watchdog_ops ftwdt010_wdt_ops = { 109 .start = ftwdt010_wdt_start, 110 .stop = ftwdt010_wdt_stop, 111 .ping = ftwdt010_wdt_ping, 112 .set_timeout = ftwdt010_wdt_set_timeout, 113 .owner = THIS_MODULE, 114 }; 115 116 static const struct watchdog_info ftwdt010_wdt_info = { 117 .options = WDIOF_KEEPALIVEPING 118 | WDIOF_MAGICCLOSE 119 | WDIOF_SETTIMEOUT, 120 .identity = KBUILD_MODNAME, 121 }; 122 123 124 static int ftwdt010_wdt_probe(struct platform_device *pdev) 125 { 126 struct device *dev = &pdev->dev; 127 struct resource *res; 128 struct ftwdt010_wdt *gwdt; 129 unsigned int reg; 130 int irq; 131 int ret; 132 133 gwdt = devm_kzalloc(dev, sizeof(*gwdt), GFP_KERNEL); 134 if (!gwdt) 135 return -ENOMEM; 136 137 res = platform_get_resource(pdev, IORESOURCE_MEM, 0); 138 gwdt->base = devm_ioremap_resource(dev, res); 139 if (IS_ERR(gwdt->base)) 140 return PTR_ERR(gwdt->base); 141 142 gwdt->dev = dev; 143 gwdt->wdd.info = &ftwdt010_wdt_info; 144 gwdt->wdd.ops = &ftwdt010_wdt_ops; 145 gwdt->wdd.min_timeout = 1; 146 gwdt->wdd.max_timeout = 0xFFFFFFFF / WDT_CLOCK; 147 gwdt->wdd.parent = dev; 148 149 /* 150 * If 'timeout-sec' unspecified in devicetree, assume a 13 second 151 * default. 152 */ 153 gwdt->wdd.timeout = 13U; 154 watchdog_init_timeout(&gwdt->wdd, 0, dev); 155 156 reg = readw(gwdt->base + FTWDT010_WDCR); 157 if (reg & WDCR_ENABLE) { 158 /* Watchdog was enabled by the bootloader, disable it. */ 159 reg &= ~WDCR_ENABLE; 160 writel(reg, gwdt->base + FTWDT010_WDCR); 161 } 162 163 irq = platform_get_irq(pdev, 0); 164 if (irq) { 165 ret = devm_request_irq(dev, irq, ftwdt010_wdt_interrupt, 0, 166 "watchdog bark", gwdt); 167 if (ret) 168 return ret; 169 gwdt->has_irq = true; 170 } 171 172 ret = devm_watchdog_register_device(dev, &gwdt->wdd); 173 if (ret) { 174 dev_err(&pdev->dev, "failed to register watchdog\n"); 175 return ret; 176 } 177 178 /* Set up platform driver data */ 179 platform_set_drvdata(pdev, gwdt); 180 dev_info(dev, "FTWDT010 watchdog driver enabled\n"); 181 182 return 0; 183 } 184 185 static int __maybe_unused ftwdt010_wdt_suspend(struct device *dev) 186 { 187 struct ftwdt010_wdt *gwdt = dev_get_drvdata(dev); 188 unsigned int reg; 189 190 reg = readw(gwdt->base + FTWDT010_WDCR); 191 reg &= ~WDCR_ENABLE; 192 writel(reg, gwdt->base + FTWDT010_WDCR); 193 194 return 0; 195 } 196 197 static int __maybe_unused ftwdt010_wdt_resume(struct device *dev) 198 { 199 struct ftwdt010_wdt *gwdt = dev_get_drvdata(dev); 200 unsigned int reg; 201 202 if (watchdog_active(&gwdt->wdd)) { 203 reg = readw(gwdt->base + FTWDT010_WDCR); 204 reg |= WDCR_ENABLE; 205 writel(reg, gwdt->base + FTWDT010_WDCR); 206 } 207 208 return 0; 209 } 210 211 static const struct dev_pm_ops ftwdt010_wdt_dev_pm_ops = { 212 SET_SYSTEM_SLEEP_PM_OPS(ftwdt010_wdt_suspend, 213 ftwdt010_wdt_resume) 214 }; 215 216 #ifdef CONFIG_OF 217 static const struct of_device_id ftwdt010_wdt_match[] = { 218 { .compatible = "faraday,ftwdt010" }, 219 { .compatible = "cortina,gemini-watchdog" }, 220 {}, 221 }; 222 MODULE_DEVICE_TABLE(of, ftwdt010_wdt_match); 223 #endif 224 225 static struct platform_driver ftwdt010_wdt_driver = { 226 .probe = ftwdt010_wdt_probe, 227 .driver = { 228 .name = "ftwdt010-wdt", 229 .of_match_table = of_match_ptr(ftwdt010_wdt_match), 230 .pm = &ftwdt010_wdt_dev_pm_ops, 231 }, 232 }; 233 module_platform_driver(ftwdt010_wdt_driver); 234 MODULE_AUTHOR("Linus Walleij"); 235 MODULE_DESCRIPTION("Watchdog driver for Faraday Technology FTWDT010"); 236 MODULE_LICENSE("GPL"); 237