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 <john@phrozen.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 static struct reset_control *rt288x_wdt_reset; 49 50 static bool nowayout = WATCHDOG_NOWAYOUT; 51 module_param(nowayout, bool, 0); 52 MODULE_PARM_DESC(nowayout, 53 "Watchdog cannot be stopped once started (default=" 54 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); 55 56 static inline void rt_wdt_w32(unsigned reg, u32 val) 57 { 58 iowrite32(val, rt288x_wdt_base + reg); 59 } 60 61 static inline u32 rt_wdt_r32(unsigned reg) 62 { 63 return ioread32(rt288x_wdt_base + reg); 64 } 65 66 static int rt288x_wdt_ping(struct watchdog_device *w) 67 { 68 rt_wdt_w32(TIMER_REG_TMR1LOAD, w->timeout * rt288x_wdt_freq); 69 70 return 0; 71 } 72 73 static int rt288x_wdt_start(struct watchdog_device *w) 74 { 75 u32 t; 76 77 t = rt_wdt_r32(TIMER_REG_TMR1CTL); 78 t &= ~(TMR1CTL_MODE_MASK << TMR1CTL_MODE_SHIFT | 79 TMR1CTL_PRESCALE_MASK); 80 t |= (TMR1CTL_MODE_WDT << TMR1CTL_MODE_SHIFT | 81 TMR1CTL_PRESCALE_65536); 82 rt_wdt_w32(TIMER_REG_TMR1CTL, t); 83 84 rt288x_wdt_ping(w); 85 86 t = rt_wdt_r32(TIMER_REG_TMR1CTL); 87 t |= TMR1CTL_ENABLE; 88 rt_wdt_w32(TIMER_REG_TMR1CTL, t); 89 90 return 0; 91 } 92 93 static int rt288x_wdt_stop(struct watchdog_device *w) 94 { 95 u32 t; 96 97 rt288x_wdt_ping(w); 98 99 t = rt_wdt_r32(TIMER_REG_TMR1CTL); 100 t &= ~TMR1CTL_ENABLE; 101 rt_wdt_w32(TIMER_REG_TMR1CTL, t); 102 103 return 0; 104 } 105 106 static int rt288x_wdt_set_timeout(struct watchdog_device *w, unsigned int t) 107 { 108 w->timeout = t; 109 rt288x_wdt_ping(w); 110 111 return 0; 112 } 113 114 static int rt288x_wdt_bootcause(void) 115 { 116 if (rt_sysc_r32(SYSC_RSTSTAT) & WDT_RST_CAUSE) 117 return WDIOF_CARDRESET; 118 119 return 0; 120 } 121 122 static const struct watchdog_info rt288x_wdt_info = { 123 .identity = "Ralink Watchdog", 124 .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE, 125 }; 126 127 static const struct watchdog_ops rt288x_wdt_ops = { 128 .owner = THIS_MODULE, 129 .start = rt288x_wdt_start, 130 .stop = rt288x_wdt_stop, 131 .ping = rt288x_wdt_ping, 132 .set_timeout = rt288x_wdt_set_timeout, 133 }; 134 135 static struct watchdog_device rt288x_wdt_dev = { 136 .info = &rt288x_wdt_info, 137 .ops = &rt288x_wdt_ops, 138 .min_timeout = 1, 139 }; 140 141 static int rt288x_wdt_probe(struct platform_device *pdev) 142 { 143 struct resource *res; 144 int ret; 145 146 res = platform_get_resource(pdev, IORESOURCE_MEM, 0); 147 rt288x_wdt_base = devm_ioremap_resource(&pdev->dev, res); 148 if (IS_ERR(rt288x_wdt_base)) 149 return PTR_ERR(rt288x_wdt_base); 150 151 rt288x_wdt_clk = devm_clk_get(&pdev->dev, NULL); 152 if (IS_ERR(rt288x_wdt_clk)) 153 return PTR_ERR(rt288x_wdt_clk); 154 155 rt288x_wdt_reset = devm_reset_control_get_exclusive(&pdev->dev, NULL); 156 if (!IS_ERR(rt288x_wdt_reset)) 157 reset_control_deassert(rt288x_wdt_reset); 158 159 rt288x_wdt_freq = clk_get_rate(rt288x_wdt_clk) / RALINK_WDT_PRESCALE; 160 161 rt288x_wdt_dev.bootstatus = rt288x_wdt_bootcause(); 162 rt288x_wdt_dev.max_timeout = (0xfffful / rt288x_wdt_freq); 163 rt288x_wdt_dev.parent = &pdev->dev; 164 165 watchdog_init_timeout(&rt288x_wdt_dev, rt288x_wdt_dev.max_timeout, 166 &pdev->dev); 167 watchdog_set_nowayout(&rt288x_wdt_dev, nowayout); 168 169 ret = watchdog_register_device(&rt288x_wdt_dev); 170 if (!ret) 171 dev_info(&pdev->dev, "Initialized\n"); 172 173 return 0; 174 } 175 176 static int rt288x_wdt_remove(struct platform_device *pdev) 177 { 178 watchdog_unregister_device(&rt288x_wdt_dev); 179 180 return 0; 181 } 182 183 static void rt288x_wdt_shutdown(struct platform_device *pdev) 184 { 185 rt288x_wdt_stop(&rt288x_wdt_dev); 186 } 187 188 static const struct of_device_id rt288x_wdt_match[] = { 189 { .compatible = "ralink,rt2880-wdt" }, 190 {}, 191 }; 192 MODULE_DEVICE_TABLE(of, rt288x_wdt_match); 193 194 static struct platform_driver rt288x_wdt_driver = { 195 .probe = rt288x_wdt_probe, 196 .remove = rt288x_wdt_remove, 197 .shutdown = rt288x_wdt_shutdown, 198 .driver = { 199 .name = KBUILD_MODNAME, 200 .of_match_table = rt288x_wdt_match, 201 }, 202 }; 203 204 module_platform_driver(rt288x_wdt_driver); 205 206 MODULE_DESCRIPTION("MediaTek/Ralink RT288x/RT3xxx hardware watchdog driver"); 207 MODULE_AUTHOR("Gabor Juhos <juhosg@openwrt.org"); 208 MODULE_LICENSE("GPL v2"); 209