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 #include <linux/mod_devicetable.h> 22 23 #include <asm/mach-ralink/ralink_regs.h> 24 25 #define SYSC_RSTSTAT 0x38 26 #define WDT_RST_CAUSE BIT(1) 27 28 #define RALINK_WDT_TIMEOUT 30 29 #define RALINK_WDT_PRESCALE 65536 30 31 #define TIMER_REG_TMR1LOAD 0x00 32 #define TIMER_REG_TMR1CTL 0x08 33 34 #define TMRSTAT_TMR1RST BIT(5) 35 36 #define TMR1CTL_ENABLE BIT(7) 37 #define TMR1CTL_MODE_SHIFT 4 38 #define TMR1CTL_MODE_MASK 0x3 39 #define TMR1CTL_MODE_FREE_RUNNING 0x0 40 #define TMR1CTL_MODE_PERIODIC 0x1 41 #define TMR1CTL_MODE_TIMEOUT 0x2 42 #define TMR1CTL_MODE_WDT 0x3 43 #define TMR1CTL_PRESCALE_MASK 0xf 44 #define TMR1CTL_PRESCALE_65536 0xf 45 46 static struct clk *rt288x_wdt_clk; 47 static unsigned long rt288x_wdt_freq; 48 static void __iomem *rt288x_wdt_base; 49 static struct reset_control *rt288x_wdt_reset; 50 51 static bool nowayout = WATCHDOG_NOWAYOUT; 52 module_param(nowayout, bool, 0); 53 MODULE_PARM_DESC(nowayout, 54 "Watchdog cannot be stopped once started (default=" 55 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); 56 57 static inline void rt_wdt_w32(unsigned reg, u32 val) 58 { 59 iowrite32(val, rt288x_wdt_base + reg); 60 } 61 62 static inline u32 rt_wdt_r32(unsigned reg) 63 { 64 return ioread32(rt288x_wdt_base + reg); 65 } 66 67 static int rt288x_wdt_ping(struct watchdog_device *w) 68 { 69 rt_wdt_w32(TIMER_REG_TMR1LOAD, w->timeout * rt288x_wdt_freq); 70 71 return 0; 72 } 73 74 static int rt288x_wdt_start(struct watchdog_device *w) 75 { 76 u32 t; 77 78 t = rt_wdt_r32(TIMER_REG_TMR1CTL); 79 t &= ~(TMR1CTL_MODE_MASK << TMR1CTL_MODE_SHIFT | 80 TMR1CTL_PRESCALE_MASK); 81 t |= (TMR1CTL_MODE_WDT << TMR1CTL_MODE_SHIFT | 82 TMR1CTL_PRESCALE_65536); 83 rt_wdt_w32(TIMER_REG_TMR1CTL, t); 84 85 rt288x_wdt_ping(w); 86 87 t = rt_wdt_r32(TIMER_REG_TMR1CTL); 88 t |= TMR1CTL_ENABLE; 89 rt_wdt_w32(TIMER_REG_TMR1CTL, t); 90 91 return 0; 92 } 93 94 static int rt288x_wdt_stop(struct watchdog_device *w) 95 { 96 u32 t; 97 98 rt288x_wdt_ping(w); 99 100 t = rt_wdt_r32(TIMER_REG_TMR1CTL); 101 t &= ~TMR1CTL_ENABLE; 102 rt_wdt_w32(TIMER_REG_TMR1CTL, t); 103 104 return 0; 105 } 106 107 static int rt288x_wdt_set_timeout(struct watchdog_device *w, unsigned int t) 108 { 109 w->timeout = t; 110 rt288x_wdt_ping(w); 111 112 return 0; 113 } 114 115 static int rt288x_wdt_bootcause(void) 116 { 117 if (rt_sysc_r32(SYSC_RSTSTAT) & WDT_RST_CAUSE) 118 return WDIOF_CARDRESET; 119 120 return 0; 121 } 122 123 static const struct watchdog_info rt288x_wdt_info = { 124 .identity = "Ralink Watchdog", 125 .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE, 126 }; 127 128 static const struct watchdog_ops rt288x_wdt_ops = { 129 .owner = THIS_MODULE, 130 .start = rt288x_wdt_start, 131 .stop = rt288x_wdt_stop, 132 .ping = rt288x_wdt_ping, 133 .set_timeout = rt288x_wdt_set_timeout, 134 }; 135 136 static struct watchdog_device rt288x_wdt_dev = { 137 .info = &rt288x_wdt_info, 138 .ops = &rt288x_wdt_ops, 139 .min_timeout = 1, 140 }; 141 142 static int rt288x_wdt_probe(struct platform_device *pdev) 143 { 144 struct resource *res; 145 int ret; 146 147 res = platform_get_resource(pdev, IORESOURCE_MEM, 0); 148 rt288x_wdt_base = devm_ioremap_resource(&pdev->dev, res); 149 if (IS_ERR(rt288x_wdt_base)) 150 return PTR_ERR(rt288x_wdt_base); 151 152 rt288x_wdt_clk = devm_clk_get(&pdev->dev, NULL); 153 if (IS_ERR(rt288x_wdt_clk)) 154 return PTR_ERR(rt288x_wdt_clk); 155 156 rt288x_wdt_reset = devm_reset_control_get_exclusive(&pdev->dev, NULL); 157 if (!IS_ERR(rt288x_wdt_reset)) 158 reset_control_deassert(rt288x_wdt_reset); 159 160 rt288x_wdt_freq = clk_get_rate(rt288x_wdt_clk) / RALINK_WDT_PRESCALE; 161 162 rt288x_wdt_dev.bootstatus = rt288x_wdt_bootcause(); 163 rt288x_wdt_dev.max_timeout = (0xfffful / rt288x_wdt_freq); 164 rt288x_wdt_dev.parent = &pdev->dev; 165 166 watchdog_init_timeout(&rt288x_wdt_dev, rt288x_wdt_dev.max_timeout, 167 &pdev->dev); 168 watchdog_set_nowayout(&rt288x_wdt_dev, nowayout); 169 170 ret = watchdog_register_device(&rt288x_wdt_dev); 171 if (!ret) 172 dev_info(&pdev->dev, "Initialized\n"); 173 174 return 0; 175 } 176 177 static int rt288x_wdt_remove(struct platform_device *pdev) 178 { 179 watchdog_unregister_device(&rt288x_wdt_dev); 180 181 return 0; 182 } 183 184 static void rt288x_wdt_shutdown(struct platform_device *pdev) 185 { 186 rt288x_wdt_stop(&rt288x_wdt_dev); 187 } 188 189 static const struct of_device_id rt288x_wdt_match[] = { 190 { .compatible = "ralink,rt2880-wdt" }, 191 {}, 192 }; 193 MODULE_DEVICE_TABLE(of, rt288x_wdt_match); 194 195 static struct platform_driver rt288x_wdt_driver = { 196 .probe = rt288x_wdt_probe, 197 .remove = rt288x_wdt_remove, 198 .shutdown = rt288x_wdt_shutdown, 199 .driver = { 200 .name = KBUILD_MODNAME, 201 .of_match_table = rt288x_wdt_match, 202 }, 203 }; 204 205 module_platform_driver(rt288x_wdt_driver); 206 207 MODULE_DESCRIPTION("MediaTek/Ralink RT288x/RT3xxx hardware watchdog driver"); 208 MODULE_AUTHOR("Gabor Juhos <juhosg@openwrt.org"); 209 MODULE_LICENSE("GPL v2"); 210