1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * txx9wdt: A Hardware Watchdog Driver for TXx9 SoCs 4 * 5 * Copyright (C) 2007 Atsushi Nemoto <anemo@mba.ocn.ne.jp> 6 */ 7 8 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 9 10 #include <linux/module.h> 11 #include <linux/moduleparam.h> 12 #include <linux/types.h> 13 #include <linux/watchdog.h> 14 #include <linux/init.h> 15 #include <linux/platform_device.h> 16 #include <linux/clk.h> 17 #include <linux/err.h> 18 #include <linux/io.h> 19 #include <asm/txx9tmr.h> 20 21 #define WD_TIMER_CCD 7 /* 1/256 */ 22 #define WD_TIMER_CLK (clk_get_rate(txx9_imclk) / (2 << WD_TIMER_CCD)) 23 #define WD_MAX_TIMEOUT ((0xffffffff >> (32 - TXX9_TIMER_BITS)) / WD_TIMER_CLK) 24 #define TIMER_MARGIN 60 /* Default is 60 seconds */ 25 26 static unsigned int timeout = TIMER_MARGIN; /* in seconds */ 27 module_param(timeout, uint, 0); 28 MODULE_PARM_DESC(timeout, 29 "Watchdog timeout in seconds. " 30 "(0<timeout<((2^" __MODULE_STRING(TXX9_TIMER_BITS) ")/(IMCLK/256)), " 31 "default=" __MODULE_STRING(TIMER_MARGIN) ")"); 32 33 static bool nowayout = WATCHDOG_NOWAYOUT; 34 module_param(nowayout, bool, 0); 35 MODULE_PARM_DESC(nowayout, 36 "Watchdog cannot be stopped once started " 37 "(default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); 38 39 static struct txx9_tmr_reg __iomem *txx9wdt_reg; 40 static struct clk *txx9_imclk; 41 static DEFINE_SPINLOCK(txx9_lock); 42 43 static int txx9wdt_ping(struct watchdog_device *wdt_dev) 44 { 45 spin_lock(&txx9_lock); 46 __raw_writel(TXx9_TMWTMR_TWIE | TXx9_TMWTMR_TWC, &txx9wdt_reg->wtmr); 47 spin_unlock(&txx9_lock); 48 return 0; 49 } 50 51 static int txx9wdt_start(struct watchdog_device *wdt_dev) 52 { 53 spin_lock(&txx9_lock); 54 __raw_writel(WD_TIMER_CLK * wdt_dev->timeout, &txx9wdt_reg->cpra); 55 __raw_writel(WD_TIMER_CCD, &txx9wdt_reg->ccdr); 56 __raw_writel(0, &txx9wdt_reg->tisr); /* clear pending interrupt */ 57 __raw_writel(TXx9_TMTCR_TCE | TXx9_TMTCR_CCDE | TXx9_TMTCR_TMODE_WDOG, 58 &txx9wdt_reg->tcr); 59 __raw_writel(TXx9_TMWTMR_TWIE | TXx9_TMWTMR_TWC, &txx9wdt_reg->wtmr); 60 spin_unlock(&txx9_lock); 61 return 0; 62 } 63 64 static int txx9wdt_stop(struct watchdog_device *wdt_dev) 65 { 66 spin_lock(&txx9_lock); 67 __raw_writel(TXx9_TMWTMR_WDIS, &txx9wdt_reg->wtmr); 68 __raw_writel(__raw_readl(&txx9wdt_reg->tcr) & ~TXx9_TMTCR_TCE, 69 &txx9wdt_reg->tcr); 70 spin_unlock(&txx9_lock); 71 return 0; 72 } 73 74 static int txx9wdt_set_timeout(struct watchdog_device *wdt_dev, 75 unsigned int new_timeout) 76 { 77 wdt_dev->timeout = new_timeout; 78 txx9wdt_stop(wdt_dev); 79 txx9wdt_start(wdt_dev); 80 return 0; 81 } 82 83 static const struct watchdog_info txx9wdt_info = { 84 .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE, 85 .identity = "Hardware Watchdog for TXx9", 86 }; 87 88 static const struct watchdog_ops txx9wdt_ops = { 89 .owner = THIS_MODULE, 90 .start = txx9wdt_start, 91 .stop = txx9wdt_stop, 92 .ping = txx9wdt_ping, 93 .set_timeout = txx9wdt_set_timeout, 94 }; 95 96 static struct watchdog_device txx9wdt = { 97 .info = &txx9wdt_info, 98 .ops = &txx9wdt_ops, 99 }; 100 101 static int __init txx9wdt_probe(struct platform_device *dev) 102 { 103 int ret; 104 105 txx9_imclk = clk_get(NULL, "imbus_clk"); 106 if (IS_ERR(txx9_imclk)) { 107 ret = PTR_ERR(txx9_imclk); 108 txx9_imclk = NULL; 109 goto exit; 110 } 111 ret = clk_prepare_enable(txx9_imclk); 112 if (ret) { 113 clk_put(txx9_imclk); 114 txx9_imclk = NULL; 115 goto exit; 116 } 117 118 txx9wdt_reg = devm_platform_ioremap_resource(dev, 0); 119 if (IS_ERR(txx9wdt_reg)) { 120 ret = PTR_ERR(txx9wdt_reg); 121 goto exit; 122 } 123 124 if (timeout < 1 || timeout > WD_MAX_TIMEOUT) 125 timeout = TIMER_MARGIN; 126 txx9wdt.timeout = timeout; 127 txx9wdt.min_timeout = 1; 128 txx9wdt.max_timeout = WD_MAX_TIMEOUT; 129 txx9wdt.parent = &dev->dev; 130 watchdog_set_nowayout(&txx9wdt, nowayout); 131 132 ret = watchdog_register_device(&txx9wdt); 133 if (ret) 134 goto exit; 135 136 pr_info("Hardware Watchdog Timer: timeout=%d sec (max %ld) (nowayout= %d)\n", 137 timeout, WD_MAX_TIMEOUT, nowayout); 138 139 return 0; 140 exit: 141 if (txx9_imclk) { 142 clk_disable_unprepare(txx9_imclk); 143 clk_put(txx9_imclk); 144 } 145 return ret; 146 } 147 148 static int __exit txx9wdt_remove(struct platform_device *dev) 149 { 150 watchdog_unregister_device(&txx9wdt); 151 clk_disable_unprepare(txx9_imclk); 152 clk_put(txx9_imclk); 153 return 0; 154 } 155 156 static void txx9wdt_shutdown(struct platform_device *dev) 157 { 158 txx9wdt_stop(&txx9wdt); 159 } 160 161 static struct platform_driver txx9wdt_driver = { 162 .remove = __exit_p(txx9wdt_remove), 163 .shutdown = txx9wdt_shutdown, 164 .driver = { 165 .name = "txx9wdt", 166 }, 167 }; 168 169 module_platform_driver_probe(txx9wdt_driver, txx9wdt_probe); 170 171 MODULE_DESCRIPTION("TXx9 Watchdog Driver"); 172 MODULE_LICENSE("GPL"); 173 MODULE_ALIAS("platform:txx9wdt"); 174