1 // SPDX-License-Identifier: GPL-2.0+ 2 /* 3 * Copyright (C) 2015 Broadcom Corporation 4 * 5 */ 6 7 #include <linux/clk.h> 8 #include <linux/init.h> 9 #include <linux/io.h> 10 #include <linux/module.h> 11 #include <linux/of.h> 12 #include <linux/platform_device.h> 13 #include <linux/platform_data/bcm7038_wdt.h> 14 #include <linux/pm.h> 15 #include <linux/watchdog.h> 16 17 #define WDT_START_1 0xff00 18 #define WDT_START_2 0x00ff 19 #define WDT_STOP_1 0xee00 20 #define WDT_STOP_2 0x00ee 21 22 #define WDT_TIMEOUT_REG 0x0 23 #define WDT_CMD_REG 0x4 24 25 #define WDT_MIN_TIMEOUT 1 /* seconds */ 26 #define WDT_DEFAULT_TIMEOUT 30 /* seconds */ 27 #define WDT_DEFAULT_RATE 27000000 28 29 struct bcm7038_watchdog { 30 void __iomem *base; 31 struct watchdog_device wdd; 32 u32 rate; 33 struct clk *clk; 34 }; 35 36 static bool nowayout = WATCHDOG_NOWAYOUT; 37 38 static inline void bcm7038_wdt_write(u32 value, void __iomem *addr) 39 { 40 /* MIPS chips strapped for BE will automagically configure the 41 * peripheral registers for CPU-native byte order. 42 */ 43 if (IS_ENABLED(CONFIG_MIPS) && IS_ENABLED(CONFIG_CPU_BIG_ENDIAN)) 44 __raw_writel(value, addr); 45 else 46 writel_relaxed(value, addr); 47 } 48 49 static inline u32 bcm7038_wdt_read(void __iomem *addr) 50 { 51 if (IS_ENABLED(CONFIG_MIPS) && IS_ENABLED(CONFIG_CPU_BIG_ENDIAN)) 52 return __raw_readl(addr); 53 else 54 return readl_relaxed(addr); 55 } 56 57 static void bcm7038_wdt_set_timeout_reg(struct watchdog_device *wdog) 58 { 59 struct bcm7038_watchdog *wdt = watchdog_get_drvdata(wdog); 60 u32 timeout; 61 62 timeout = wdt->rate * wdog->timeout; 63 64 bcm7038_wdt_write(timeout, wdt->base + WDT_TIMEOUT_REG); 65 } 66 67 static int bcm7038_wdt_ping(struct watchdog_device *wdog) 68 { 69 struct bcm7038_watchdog *wdt = watchdog_get_drvdata(wdog); 70 71 bcm7038_wdt_write(WDT_START_1, wdt->base + WDT_CMD_REG); 72 bcm7038_wdt_write(WDT_START_2, wdt->base + WDT_CMD_REG); 73 74 return 0; 75 } 76 77 static int bcm7038_wdt_start(struct watchdog_device *wdog) 78 { 79 bcm7038_wdt_set_timeout_reg(wdog); 80 bcm7038_wdt_ping(wdog); 81 82 return 0; 83 } 84 85 static int bcm7038_wdt_stop(struct watchdog_device *wdog) 86 { 87 struct bcm7038_watchdog *wdt = watchdog_get_drvdata(wdog); 88 89 bcm7038_wdt_write(WDT_STOP_1, wdt->base + WDT_CMD_REG); 90 bcm7038_wdt_write(WDT_STOP_2, wdt->base + WDT_CMD_REG); 91 92 return 0; 93 } 94 95 static int bcm7038_wdt_set_timeout(struct watchdog_device *wdog, 96 unsigned int t) 97 { 98 /* Can't modify timeout value if watchdog timer is running */ 99 bcm7038_wdt_stop(wdog); 100 wdog->timeout = t; 101 bcm7038_wdt_start(wdog); 102 103 return 0; 104 } 105 106 static unsigned int bcm7038_wdt_get_timeleft(struct watchdog_device *wdog) 107 { 108 struct bcm7038_watchdog *wdt = watchdog_get_drvdata(wdog); 109 u32 time_left; 110 111 time_left = bcm7038_wdt_read(wdt->base + WDT_CMD_REG); 112 113 return time_left / wdt->rate; 114 } 115 116 static const struct watchdog_info bcm7038_wdt_info = { 117 .identity = "Broadcom BCM7038 Watchdog Timer", 118 .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | 119 WDIOF_MAGICCLOSE 120 }; 121 122 static const struct watchdog_ops bcm7038_wdt_ops = { 123 .owner = THIS_MODULE, 124 .start = bcm7038_wdt_start, 125 .stop = bcm7038_wdt_stop, 126 .set_timeout = bcm7038_wdt_set_timeout, 127 .get_timeleft = bcm7038_wdt_get_timeleft, 128 }; 129 130 static int bcm7038_wdt_probe(struct platform_device *pdev) 131 { 132 struct bcm7038_wdt_platform_data *pdata = pdev->dev.platform_data; 133 struct device *dev = &pdev->dev; 134 struct bcm7038_watchdog *wdt; 135 const char *clk_name = NULL; 136 int err; 137 138 wdt = devm_kzalloc(dev, sizeof(*wdt), GFP_KERNEL); 139 if (!wdt) 140 return -ENOMEM; 141 142 platform_set_drvdata(pdev, wdt); 143 144 wdt->base = devm_platform_ioremap_resource(pdev, 0); 145 if (IS_ERR(wdt->base)) 146 return PTR_ERR(wdt->base); 147 148 if (pdata && pdata->clk_name) 149 clk_name = pdata->clk_name; 150 151 wdt->clk = devm_clk_get_enabled(dev, clk_name); 152 /* If unable to get clock, use default frequency */ 153 if (!IS_ERR(wdt->clk)) { 154 wdt->rate = clk_get_rate(wdt->clk); 155 /* Prevent divide-by-zero exception */ 156 if (!wdt->rate) 157 wdt->rate = WDT_DEFAULT_RATE; 158 } else { 159 wdt->rate = WDT_DEFAULT_RATE; 160 wdt->clk = NULL; 161 } 162 163 wdt->wdd.info = &bcm7038_wdt_info; 164 wdt->wdd.ops = &bcm7038_wdt_ops; 165 wdt->wdd.min_timeout = WDT_MIN_TIMEOUT; 166 wdt->wdd.timeout = WDT_DEFAULT_TIMEOUT; 167 wdt->wdd.max_timeout = 0xffffffff / wdt->rate; 168 wdt->wdd.parent = dev; 169 watchdog_set_drvdata(&wdt->wdd, wdt); 170 171 watchdog_stop_on_reboot(&wdt->wdd); 172 watchdog_stop_on_unregister(&wdt->wdd); 173 err = devm_watchdog_register_device(dev, &wdt->wdd); 174 if (err) 175 return err; 176 177 dev_info(dev, "Registered BCM7038 Watchdog\n"); 178 179 return 0; 180 } 181 182 static int bcm7038_wdt_suspend(struct device *dev) 183 { 184 struct bcm7038_watchdog *wdt = dev_get_drvdata(dev); 185 186 if (watchdog_active(&wdt->wdd)) 187 return bcm7038_wdt_stop(&wdt->wdd); 188 189 return 0; 190 } 191 192 static int bcm7038_wdt_resume(struct device *dev) 193 { 194 struct bcm7038_watchdog *wdt = dev_get_drvdata(dev); 195 196 if (watchdog_active(&wdt->wdd)) 197 return bcm7038_wdt_start(&wdt->wdd); 198 199 return 0; 200 } 201 202 static DEFINE_SIMPLE_DEV_PM_OPS(bcm7038_wdt_pm_ops, 203 bcm7038_wdt_suspend, bcm7038_wdt_resume); 204 205 static const struct of_device_id bcm7038_wdt_match[] = { 206 { .compatible = "brcm,bcm6345-wdt" }, 207 { .compatible = "brcm,bcm7038-wdt" }, 208 {}, 209 }; 210 MODULE_DEVICE_TABLE(of, bcm7038_wdt_match); 211 212 static const struct platform_device_id bcm7038_wdt_devtype[] = { 213 { .name = "bcm63xx-wdt" }, 214 { /* sentinel */ }, 215 }; 216 MODULE_DEVICE_TABLE(platform, bcm7038_wdt_devtype); 217 218 static struct platform_driver bcm7038_wdt_driver = { 219 .probe = bcm7038_wdt_probe, 220 .id_table = bcm7038_wdt_devtype, 221 .driver = { 222 .name = "bcm7038-wdt", 223 .of_match_table = bcm7038_wdt_match, 224 .pm = pm_sleep_ptr(&bcm7038_wdt_pm_ops), 225 } 226 }; 227 module_platform_driver(bcm7038_wdt_driver); 228 229 module_param(nowayout, bool, 0); 230 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" 231 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); 232 MODULE_LICENSE("GPL"); 233 MODULE_DESCRIPTION("Driver for Broadcom 7038 SoCs Watchdog"); 234 MODULE_AUTHOR("Justin Chen"); 235