1 /* 2 * txx9wdt: A Hardware Watchdog Driver for TXx9 SoCs 3 * 4 * Copyright (C) 2007 Atsushi Nemoto <anemo@mba.ocn.ne.jp> 5 * 6 * This program is free software; you can redistribute it and/or modify 7 * it under the terms of the GNU General Public License version 2 as 8 * published by the Free Software Foundation. 9 */ 10 11 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 12 13 #include <linux/module.h> 14 #include <linux/moduleparam.h> 15 #include <linux/types.h> 16 #include <linux/watchdog.h> 17 #include <linux/init.h> 18 #include <linux/platform_device.h> 19 #include <linux/clk.h> 20 #include <linux/err.h> 21 #include <linux/io.h> 22 #include <asm/txx9tmr.h> 23 24 #define WD_TIMER_CCD 7 /* 1/256 */ 25 #define WD_TIMER_CLK (clk_get_rate(txx9_imclk) / (2 << WD_TIMER_CCD)) 26 #define WD_MAX_TIMEOUT ((0xffffffff >> (32 - TXX9_TIMER_BITS)) / WD_TIMER_CLK) 27 #define TIMER_MARGIN 60 /* Default is 60 seconds */ 28 29 static unsigned int timeout = TIMER_MARGIN; /* in seconds */ 30 module_param(timeout, uint, 0); 31 MODULE_PARM_DESC(timeout, 32 "Watchdog timeout in seconds. " 33 "(0<timeout<((2^" __MODULE_STRING(TXX9_TIMER_BITS) ")/(IMCLK/256)), " 34 "default=" __MODULE_STRING(TIMER_MARGIN) ")"); 35 36 static bool nowayout = WATCHDOG_NOWAYOUT; 37 module_param(nowayout, bool, 0); 38 MODULE_PARM_DESC(nowayout, 39 "Watchdog cannot be stopped once started " 40 "(default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); 41 42 static struct txx9_tmr_reg __iomem *txx9wdt_reg; 43 static struct clk *txx9_imclk; 44 static DEFINE_SPINLOCK(txx9_lock); 45 46 static int txx9wdt_ping(struct watchdog_device *wdt_dev) 47 { 48 spin_lock(&txx9_lock); 49 __raw_writel(TXx9_TMWTMR_TWIE | TXx9_TMWTMR_TWC, &txx9wdt_reg->wtmr); 50 spin_unlock(&txx9_lock); 51 return 0; 52 } 53 54 static int txx9wdt_start(struct watchdog_device *wdt_dev) 55 { 56 spin_lock(&txx9_lock); 57 __raw_writel(WD_TIMER_CLK * wdt_dev->timeout, &txx9wdt_reg->cpra); 58 __raw_writel(WD_TIMER_CCD, &txx9wdt_reg->ccdr); 59 __raw_writel(0, &txx9wdt_reg->tisr); /* clear pending interrupt */ 60 __raw_writel(TXx9_TMTCR_TCE | TXx9_TMTCR_CCDE | TXx9_TMTCR_TMODE_WDOG, 61 &txx9wdt_reg->tcr); 62 __raw_writel(TXx9_TMWTMR_TWIE | TXx9_TMWTMR_TWC, &txx9wdt_reg->wtmr); 63 spin_unlock(&txx9_lock); 64 return 0; 65 } 66 67 static int txx9wdt_stop(struct watchdog_device *wdt_dev) 68 { 69 spin_lock(&txx9_lock); 70 __raw_writel(TXx9_TMWTMR_WDIS, &txx9wdt_reg->wtmr); 71 __raw_writel(__raw_readl(&txx9wdt_reg->tcr) & ~TXx9_TMTCR_TCE, 72 &txx9wdt_reg->tcr); 73 spin_unlock(&txx9_lock); 74 return 0; 75 } 76 77 static int txx9wdt_set_timeout(struct watchdog_device *wdt_dev, 78 unsigned int new_timeout) 79 { 80 wdt_dev->timeout = new_timeout; 81 txx9wdt_stop(wdt_dev); 82 txx9wdt_start(wdt_dev); 83 return 0; 84 } 85 86 static const struct watchdog_info txx9wdt_info = { 87 .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE, 88 .identity = "Hardware Watchdog for TXx9", 89 }; 90 91 static const struct watchdog_ops txx9wdt_ops = { 92 .owner = THIS_MODULE, 93 .start = txx9wdt_start, 94 .stop = txx9wdt_stop, 95 .ping = txx9wdt_ping, 96 .set_timeout = txx9wdt_set_timeout, 97 }; 98 99 static struct watchdog_device txx9wdt = { 100 .info = &txx9wdt_info, 101 .ops = &txx9wdt_ops, 102 }; 103 104 static int __init txx9wdt_probe(struct platform_device *dev) 105 { 106 struct resource *res; 107 int ret; 108 109 txx9_imclk = clk_get(NULL, "imbus_clk"); 110 if (IS_ERR(txx9_imclk)) { 111 ret = PTR_ERR(txx9_imclk); 112 txx9_imclk = NULL; 113 goto exit; 114 } 115 ret = clk_prepare_enable(txx9_imclk); 116 if (ret) { 117 clk_put(txx9_imclk); 118 txx9_imclk = NULL; 119 goto exit; 120 } 121 122 res = platform_get_resource(dev, IORESOURCE_MEM, 0); 123 txx9wdt_reg = devm_ioremap_resource(&dev->dev, res); 124 if (IS_ERR(txx9wdt_reg)) { 125 ret = PTR_ERR(txx9wdt_reg); 126 goto exit; 127 } 128 129 if (timeout < 1 || timeout > WD_MAX_TIMEOUT) 130 timeout = TIMER_MARGIN; 131 txx9wdt.timeout = timeout; 132 txx9wdt.min_timeout = 1; 133 txx9wdt.max_timeout = WD_MAX_TIMEOUT; 134 txx9wdt.parent = &dev->dev; 135 watchdog_set_nowayout(&txx9wdt, nowayout); 136 137 ret = watchdog_register_device(&txx9wdt); 138 if (ret) 139 goto exit; 140 141 pr_info("Hardware Watchdog Timer: timeout=%d sec (max %ld) (nowayout= %d)\n", 142 timeout, WD_MAX_TIMEOUT, nowayout); 143 144 return 0; 145 exit: 146 if (txx9_imclk) { 147 clk_disable_unprepare(txx9_imclk); 148 clk_put(txx9_imclk); 149 } 150 return ret; 151 } 152 153 static int __exit txx9wdt_remove(struct platform_device *dev) 154 { 155 watchdog_unregister_device(&txx9wdt); 156 clk_disable_unprepare(txx9_imclk); 157 clk_put(txx9_imclk); 158 return 0; 159 } 160 161 static void txx9wdt_shutdown(struct platform_device *dev) 162 { 163 txx9wdt_stop(&txx9wdt); 164 } 165 166 static struct platform_driver txx9wdt_driver = { 167 .remove = __exit_p(txx9wdt_remove), 168 .shutdown = txx9wdt_shutdown, 169 .driver = { 170 .name = "txx9wdt", 171 }, 172 }; 173 174 module_platform_driver_probe(txx9wdt_driver, txx9wdt_probe); 175 176 MODULE_DESCRIPTION("TXx9 Watchdog Driver"); 177 MODULE_LICENSE("GPL"); 178 MODULE_ALIAS("platform:txx9wdt"); 179