1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * Copyright (C) 2010, Paul Cercueil <paul@crapouillou.net> 4 * JZ4740 Watchdog driver 5 */ 6 7 #include <linux/mfd/ingenic-tcu.h> 8 #include <linux/module.h> 9 #include <linux/moduleparam.h> 10 #include <linux/types.h> 11 #include <linux/kernel.h> 12 #include <linux/watchdog.h> 13 #include <linux/platform_device.h> 14 #include <linux/io.h> 15 #include <linux/device.h> 16 #include <linux/clk.h> 17 #include <linux/slab.h> 18 #include <linux/err.h> 19 #include <linux/of.h> 20 21 #define DEFAULT_HEARTBEAT 5 22 #define MAX_HEARTBEAT 2048 23 24 static bool nowayout = WATCHDOG_NOWAYOUT; 25 module_param(nowayout, bool, 0); 26 MODULE_PARM_DESC(nowayout, 27 "Watchdog cannot be stopped once started (default=" 28 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); 29 30 static unsigned int heartbeat = DEFAULT_HEARTBEAT; 31 module_param(heartbeat, uint, 0); 32 MODULE_PARM_DESC(heartbeat, 33 "Watchdog heartbeat period in seconds from 1 to " 34 __MODULE_STRING(MAX_HEARTBEAT) ", default " 35 __MODULE_STRING(DEFAULT_HEARTBEAT)); 36 37 struct jz4740_wdt_drvdata { 38 struct watchdog_device wdt; 39 void __iomem *base; 40 struct clk *clk; 41 unsigned long clk_rate; 42 }; 43 44 static int jz4740_wdt_ping(struct watchdog_device *wdt_dev) 45 { 46 struct jz4740_wdt_drvdata *drvdata = watchdog_get_drvdata(wdt_dev); 47 48 writew(0x0, drvdata->base + TCU_REG_WDT_TCNT); 49 return 0; 50 } 51 52 static int jz4740_wdt_set_timeout(struct watchdog_device *wdt_dev, 53 unsigned int new_timeout) 54 { 55 struct jz4740_wdt_drvdata *drvdata = watchdog_get_drvdata(wdt_dev); 56 u16 timeout_value = (u16)(drvdata->clk_rate * new_timeout); 57 u8 tcer; 58 59 tcer = readb(drvdata->base + TCU_REG_WDT_TCER); 60 writeb(0x0, drvdata->base + TCU_REG_WDT_TCER); 61 62 writew((u16)timeout_value, drvdata->base + TCU_REG_WDT_TDR); 63 writew(0x0, drvdata->base + TCU_REG_WDT_TCNT); 64 65 if (tcer & TCU_WDT_TCER_TCEN) 66 writeb(TCU_WDT_TCER_TCEN, drvdata->base + TCU_REG_WDT_TCER); 67 68 wdt_dev->timeout = new_timeout; 69 return 0; 70 } 71 72 static int jz4740_wdt_start(struct watchdog_device *wdt_dev) 73 { 74 struct jz4740_wdt_drvdata *drvdata = watchdog_get_drvdata(wdt_dev); 75 int ret; 76 u8 tcer; 77 78 ret = clk_prepare_enable(drvdata->clk); 79 if (ret) 80 return ret; 81 82 tcer = readb(drvdata->base + TCU_REG_WDT_TCER); 83 84 jz4740_wdt_set_timeout(wdt_dev, wdt_dev->timeout); 85 86 /* Start watchdog if it wasn't started already */ 87 if (!(tcer & TCU_WDT_TCER_TCEN)) 88 writeb(TCU_WDT_TCER_TCEN, drvdata->base + TCU_REG_WDT_TCER); 89 90 return 0; 91 } 92 93 static int jz4740_wdt_stop(struct watchdog_device *wdt_dev) 94 { 95 struct jz4740_wdt_drvdata *drvdata = watchdog_get_drvdata(wdt_dev); 96 97 writeb(0x0, drvdata->base + TCU_REG_WDT_TCER); 98 clk_disable_unprepare(drvdata->clk); 99 100 return 0; 101 } 102 103 static int jz4740_wdt_restart(struct watchdog_device *wdt_dev, 104 unsigned long action, void *data) 105 { 106 wdt_dev->timeout = 0; 107 jz4740_wdt_start(wdt_dev); 108 return 0; 109 } 110 111 static const struct watchdog_info jz4740_wdt_info = { 112 .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE, 113 .identity = "jz4740 Watchdog", 114 }; 115 116 static const struct watchdog_ops jz4740_wdt_ops = { 117 .owner = THIS_MODULE, 118 .start = jz4740_wdt_start, 119 .stop = jz4740_wdt_stop, 120 .ping = jz4740_wdt_ping, 121 .set_timeout = jz4740_wdt_set_timeout, 122 .restart = jz4740_wdt_restart, 123 }; 124 125 #ifdef CONFIG_OF 126 static const struct of_device_id jz4740_wdt_of_matches[] = { 127 { .compatible = "ingenic,jz4740-watchdog", }, 128 { .compatible = "ingenic,jz4780-watchdog", }, 129 { /* sentinel */ } 130 }; 131 MODULE_DEVICE_TABLE(of, jz4740_wdt_of_matches); 132 #endif 133 134 static int jz4740_wdt_probe(struct platform_device *pdev) 135 { 136 struct device *dev = &pdev->dev; 137 struct jz4740_wdt_drvdata *drvdata; 138 struct watchdog_device *jz4740_wdt; 139 long rate; 140 int ret; 141 142 drvdata = devm_kzalloc(dev, sizeof(struct jz4740_wdt_drvdata), 143 GFP_KERNEL); 144 if (!drvdata) 145 return -ENOMEM; 146 147 drvdata->clk = devm_clk_get(&pdev->dev, "wdt"); 148 if (IS_ERR(drvdata->clk)) { 149 dev_err(&pdev->dev, "cannot find WDT clock\n"); 150 return PTR_ERR(drvdata->clk); 151 } 152 153 /* Set smallest clock possible */ 154 rate = clk_round_rate(drvdata->clk, 1); 155 if (rate < 0) 156 return rate; 157 158 ret = clk_set_rate(drvdata->clk, rate); 159 if (ret) 160 return ret; 161 162 drvdata->clk_rate = rate; 163 jz4740_wdt = &drvdata->wdt; 164 jz4740_wdt->info = &jz4740_wdt_info; 165 jz4740_wdt->ops = &jz4740_wdt_ops; 166 jz4740_wdt->min_timeout = 1; 167 jz4740_wdt->max_timeout = 0xffff / rate; 168 jz4740_wdt->timeout = clamp(heartbeat, 169 jz4740_wdt->min_timeout, 170 jz4740_wdt->max_timeout); 171 jz4740_wdt->parent = dev; 172 watchdog_set_nowayout(jz4740_wdt, nowayout); 173 watchdog_set_drvdata(jz4740_wdt, drvdata); 174 175 drvdata->base = devm_platform_ioremap_resource(pdev, 0); 176 if (IS_ERR(drvdata->base)) 177 return PTR_ERR(drvdata->base); 178 179 return devm_watchdog_register_device(dev, &drvdata->wdt); 180 } 181 182 static struct platform_driver jz4740_wdt_driver = { 183 .probe = jz4740_wdt_probe, 184 .driver = { 185 .name = "jz4740-wdt", 186 .of_match_table = of_match_ptr(jz4740_wdt_of_matches), 187 }, 188 }; 189 190 module_platform_driver(jz4740_wdt_driver); 191 192 MODULE_AUTHOR("Paul Cercueil <paul@crapouillou.net>"); 193 MODULE_DESCRIPTION("jz4740 Watchdog Driver"); 194 MODULE_LICENSE("GPL"); 195 MODULE_ALIAS("platform:jz4740-wdt"); 196