1 /* 2 * Ralink RT288x/RT3xxx/MT76xx built-in hardware watchdog timer 3 * 4 * Copyright (C) 2011 Gabor Juhos <juhosg@openwrt.org> 5 * Copyright (C) 2013 John Crispin <blogic@openwrt.org> 6 * 7 * This driver was based on: drivers/watchdog/softdog.c 8 * 9 * This program is free software; you can redistribute it and/or modify it 10 * under the terms of the GNU General Public License version 2 as published 11 * by the Free Software Foundation. 12 */ 13 14 #include <linux/clk.h> 15 #include <linux/reset.h> 16 #include <linux/module.h> 17 #include <linux/kernel.h> 18 #include <linux/watchdog.h> 19 #include <linux/moduleparam.h> 20 #include <linux/platform_device.h> 21 22 #include <asm/mach-ralink/ralink_regs.h> 23 24 #define SYSC_RSTSTAT 0x38 25 #define WDT_RST_CAUSE BIT(1) 26 27 #define RALINK_WDT_TIMEOUT 30 28 #define RALINK_WDT_PRESCALE 65536 29 30 #define TIMER_REG_TMR1LOAD 0x00 31 #define TIMER_REG_TMR1CTL 0x08 32 33 #define TMRSTAT_TMR1RST BIT(5) 34 35 #define TMR1CTL_ENABLE BIT(7) 36 #define TMR1CTL_MODE_SHIFT 4 37 #define TMR1CTL_MODE_MASK 0x3 38 #define TMR1CTL_MODE_FREE_RUNNING 0x0 39 #define TMR1CTL_MODE_PERIODIC 0x1 40 #define TMR1CTL_MODE_TIMEOUT 0x2 41 #define TMR1CTL_MODE_WDT 0x3 42 #define TMR1CTL_PRESCALE_MASK 0xf 43 #define TMR1CTL_PRESCALE_65536 0xf 44 45 static struct clk *rt288x_wdt_clk; 46 static unsigned long rt288x_wdt_freq; 47 static void __iomem *rt288x_wdt_base; 48 49 static bool nowayout = WATCHDOG_NOWAYOUT; 50 module_param(nowayout, bool, 0); 51 MODULE_PARM_DESC(nowayout, 52 "Watchdog cannot be stopped once started (default=" 53 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); 54 55 static inline void rt_wdt_w32(unsigned reg, u32 val) 56 { 57 iowrite32(val, rt288x_wdt_base + reg); 58 } 59 60 static inline u32 rt_wdt_r32(unsigned reg) 61 { 62 return ioread32(rt288x_wdt_base + reg); 63 } 64 65 static int rt288x_wdt_ping(struct watchdog_device *w) 66 { 67 rt_wdt_w32(TIMER_REG_TMR1LOAD, w->timeout * rt288x_wdt_freq); 68 69 return 0; 70 } 71 72 static int rt288x_wdt_start(struct watchdog_device *w) 73 { 74 u32 t; 75 76 t = rt_wdt_r32(TIMER_REG_TMR1CTL); 77 t &= ~(TMR1CTL_MODE_MASK << TMR1CTL_MODE_SHIFT | 78 TMR1CTL_PRESCALE_MASK); 79 t |= (TMR1CTL_MODE_WDT << TMR1CTL_MODE_SHIFT | 80 TMR1CTL_PRESCALE_65536); 81 rt_wdt_w32(TIMER_REG_TMR1CTL, t); 82 83 rt288x_wdt_ping(w); 84 85 t = rt_wdt_r32(TIMER_REG_TMR1CTL); 86 t |= TMR1CTL_ENABLE; 87 rt_wdt_w32(TIMER_REG_TMR1CTL, t); 88 89 return 0; 90 } 91 92 static int rt288x_wdt_stop(struct watchdog_device *w) 93 { 94 u32 t; 95 96 rt288x_wdt_ping(w); 97 98 t = rt_wdt_r32(TIMER_REG_TMR1CTL); 99 t &= ~TMR1CTL_ENABLE; 100 rt_wdt_w32(TIMER_REG_TMR1CTL, t); 101 102 return 0; 103 } 104 105 static int rt288x_wdt_set_timeout(struct watchdog_device *w, unsigned int t) 106 { 107 w->timeout = t; 108 rt288x_wdt_ping(w); 109 110 return 0; 111 } 112 113 static int rt288x_wdt_bootcause(void) 114 { 115 if (rt_sysc_r32(SYSC_RSTSTAT) & WDT_RST_CAUSE) 116 return WDIOF_CARDRESET; 117 118 return 0; 119 } 120 121 static struct watchdog_info rt288x_wdt_info = { 122 .identity = "Ralink Watchdog", 123 .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE, 124 }; 125 126 static struct watchdog_ops rt288x_wdt_ops = { 127 .owner = THIS_MODULE, 128 .start = rt288x_wdt_start, 129 .stop = rt288x_wdt_stop, 130 .ping = rt288x_wdt_ping, 131 .set_timeout = rt288x_wdt_set_timeout, 132 }; 133 134 static struct watchdog_device rt288x_wdt_dev = { 135 .info = &rt288x_wdt_info, 136 .ops = &rt288x_wdt_ops, 137 .min_timeout = 1, 138 }; 139 140 static int rt288x_wdt_probe(struct platform_device *pdev) 141 { 142 struct resource *res; 143 int ret; 144 145 res = platform_get_resource(pdev, IORESOURCE_MEM, 0); 146 rt288x_wdt_base = devm_ioremap_resource(&pdev->dev, res); 147 if (IS_ERR(rt288x_wdt_base)) 148 return PTR_ERR(rt288x_wdt_base); 149 150 rt288x_wdt_clk = devm_clk_get(&pdev->dev, NULL); 151 if (IS_ERR(rt288x_wdt_clk)) 152 return PTR_ERR(rt288x_wdt_clk); 153 154 device_reset(&pdev->dev); 155 156 rt288x_wdt_freq = clk_get_rate(rt288x_wdt_clk) / RALINK_WDT_PRESCALE; 157 158 rt288x_wdt_dev.dev = &pdev->dev; 159 rt288x_wdt_dev.bootstatus = rt288x_wdt_bootcause(); 160 161 rt288x_wdt_dev.max_timeout = (0xfffful / rt288x_wdt_freq); 162 rt288x_wdt_dev.timeout = rt288x_wdt_dev.max_timeout; 163 164 watchdog_set_nowayout(&rt288x_wdt_dev, nowayout); 165 166 ret = watchdog_register_device(&rt288x_wdt_dev); 167 if (!ret) 168 dev_info(&pdev->dev, "Initialized\n"); 169 170 return 0; 171 } 172 173 static int rt288x_wdt_remove(struct platform_device *pdev) 174 { 175 watchdog_unregister_device(&rt288x_wdt_dev); 176 177 return 0; 178 } 179 180 static void rt288x_wdt_shutdown(struct platform_device *pdev) 181 { 182 rt288x_wdt_stop(&rt288x_wdt_dev); 183 } 184 185 static const struct of_device_id rt288x_wdt_match[] = { 186 { .compatible = "ralink,rt2880-wdt" }, 187 {}, 188 }; 189 MODULE_DEVICE_TABLE(of, rt288x_wdt_match); 190 191 static struct platform_driver rt288x_wdt_driver = { 192 .probe = rt288x_wdt_probe, 193 .remove = rt288x_wdt_remove, 194 .shutdown = rt288x_wdt_shutdown, 195 .driver = { 196 .name = KBUILD_MODNAME, 197 .owner = THIS_MODULE, 198 .of_match_table = rt288x_wdt_match, 199 }, 200 }; 201 202 module_platform_driver(rt288x_wdt_driver); 203 204 MODULE_DESCRIPTION("MediaTek/Ralink RT288x/RT3xxx hardware watchdog driver"); 205 MODULE_AUTHOR("Gabor Juhos <juhosg@openwrt.org"); 206 MODULE_LICENSE("GPL v2"); 207