1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * drivers/char/watchdog/ixp4xx_wdt.c 4 * 5 * Watchdog driver for Intel IXP4xx network processors 6 * 7 * Author: Deepak Saxena <dsaxena@plexity.net> 8 * Author: Linus Walleij <linus.walleij@linaro.org> 9 * 10 * Copyright 2004 (c) MontaVista, Software, Inc. 11 * Based on sa1100 driver, Copyright (C) 2000 Oleg Drokin <green@crimea.edu> 12 */ 13 14 #include <linux/module.h> 15 #include <linux/types.h> 16 #include <linux/kernel.h> 17 #include <linux/watchdog.h> 18 #include <linux/bits.h> 19 #include <linux/platform_device.h> 20 #include <linux/clk.h> 21 #include <linux/soc/ixp4xx/cpu.h> 22 23 struct ixp4xx_wdt { 24 struct watchdog_device wdd; 25 void __iomem *base; 26 unsigned long rate; 27 }; 28 29 /* Fallback if we do not have a clock for this */ 30 #define IXP4XX_TIMER_FREQ 66666000 31 32 /* Registers after the timer registers */ 33 #define IXP4XX_OSWT_OFFSET 0x14 /* Watchdog Timer */ 34 #define IXP4XX_OSWE_OFFSET 0x18 /* Watchdog Enable */ 35 #define IXP4XX_OSWK_OFFSET 0x1C /* Watchdog Key */ 36 #define IXP4XX_OSST_OFFSET 0x20 /* Timer Status */ 37 38 #define IXP4XX_OSST_TIMER_WDOG_PEND 0x00000008 39 #define IXP4XX_OSST_TIMER_WARM_RESET 0x00000010 40 #define IXP4XX_WDT_KEY 0x0000482E 41 #define IXP4XX_WDT_RESET_ENABLE 0x00000001 42 #define IXP4XX_WDT_IRQ_ENABLE 0x00000002 43 #define IXP4XX_WDT_COUNT_ENABLE 0x00000004 44 45 static inline 46 struct ixp4xx_wdt *to_ixp4xx_wdt(struct watchdog_device *wdd) 47 { 48 return container_of(wdd, struct ixp4xx_wdt, wdd); 49 } 50 51 static int ixp4xx_wdt_start(struct watchdog_device *wdd) 52 { 53 struct ixp4xx_wdt *iwdt = to_ixp4xx_wdt(wdd); 54 55 __raw_writel(IXP4XX_WDT_KEY, iwdt->base + IXP4XX_OSWK_OFFSET); 56 __raw_writel(0, iwdt->base + IXP4XX_OSWE_OFFSET); 57 __raw_writel(wdd->timeout * iwdt->rate, 58 iwdt->base + IXP4XX_OSWT_OFFSET); 59 __raw_writel(IXP4XX_WDT_COUNT_ENABLE | IXP4XX_WDT_RESET_ENABLE, 60 iwdt->base + IXP4XX_OSWE_OFFSET); 61 __raw_writel(0, iwdt->base + IXP4XX_OSWK_OFFSET); 62 63 return 0; 64 } 65 66 static int ixp4xx_wdt_stop(struct watchdog_device *wdd) 67 { 68 struct ixp4xx_wdt *iwdt = to_ixp4xx_wdt(wdd); 69 70 __raw_writel(IXP4XX_WDT_KEY, iwdt->base + IXP4XX_OSWK_OFFSET); 71 __raw_writel(0, iwdt->base + IXP4XX_OSWE_OFFSET); 72 __raw_writel(0, iwdt->base + IXP4XX_OSWK_OFFSET); 73 74 return 0; 75 } 76 77 static int ixp4xx_wdt_set_timeout(struct watchdog_device *wdd, 78 unsigned int timeout) 79 { 80 wdd->timeout = timeout; 81 if (watchdog_active(wdd)) 82 ixp4xx_wdt_start(wdd); 83 84 return 0; 85 } 86 87 static const struct watchdog_ops ixp4xx_wdt_ops = { 88 .start = ixp4xx_wdt_start, 89 .stop = ixp4xx_wdt_stop, 90 .set_timeout = ixp4xx_wdt_set_timeout, 91 .owner = THIS_MODULE, 92 }; 93 94 static const struct watchdog_info ixp4xx_wdt_info = { 95 .options = WDIOF_KEEPALIVEPING 96 | WDIOF_MAGICCLOSE 97 | WDIOF_SETTIMEOUT, 98 .identity = KBUILD_MODNAME, 99 }; 100 101 /* Devres-handled clock disablement */ 102 static void ixp4xx_clock_action(void *d) 103 { 104 clk_disable_unprepare(d); 105 } 106 107 static int ixp4xx_wdt_probe(struct platform_device *pdev) 108 { 109 struct device *dev = &pdev->dev; 110 struct ixp4xx_wdt *iwdt; 111 struct clk *clk; 112 int ret; 113 114 if (!(read_cpuid_id() & 0xf) && !cpu_is_ixp46x()) { 115 dev_err(dev, "Rev. A0 IXP42x CPU detected - watchdog disabled\n"); 116 return -ENODEV; 117 } 118 119 iwdt = devm_kzalloc(dev, sizeof(*iwdt), GFP_KERNEL); 120 if (!iwdt) 121 return -ENOMEM; 122 iwdt->base = dev->platform_data; 123 124 /* 125 * Retrieve rate from a fixed clock from the device tree if 126 * the parent has that, else use the default clock rate. 127 */ 128 clk = devm_clk_get(dev->parent, NULL); 129 if (!IS_ERR(clk)) { 130 ret = clk_prepare_enable(clk); 131 if (ret) 132 return ret; 133 ret = devm_add_action_or_reset(dev, ixp4xx_clock_action, clk); 134 if (ret) 135 return ret; 136 iwdt->rate = clk_get_rate(clk); 137 } 138 if (!iwdt->rate) 139 iwdt->rate = IXP4XX_TIMER_FREQ; 140 141 iwdt->wdd.info = &ixp4xx_wdt_info; 142 iwdt->wdd.ops = &ixp4xx_wdt_ops; 143 iwdt->wdd.min_timeout = 1; 144 iwdt->wdd.max_timeout = U32_MAX / iwdt->rate; 145 iwdt->wdd.parent = dev; 146 /* Default to 60 seconds */ 147 iwdt->wdd.timeout = 60U; 148 watchdog_init_timeout(&iwdt->wdd, 0, dev); 149 150 if (__raw_readl(iwdt->base + IXP4XX_OSST_OFFSET) & 151 IXP4XX_OSST_TIMER_WARM_RESET) 152 iwdt->wdd.bootstatus = WDIOF_CARDRESET; 153 154 ret = devm_watchdog_register_device(dev, &iwdt->wdd); 155 if (ret) 156 return ret; 157 158 dev_info(dev, "IXP4xx watchdog available\n"); 159 160 return 0; 161 } 162 163 static struct platform_driver ixp4xx_wdt_driver = { 164 .probe = ixp4xx_wdt_probe, 165 .driver = { 166 .name = "ixp4xx-watchdog", 167 }, 168 }; 169 module_platform_driver(ixp4xx_wdt_driver); 170 171 MODULE_AUTHOR("Deepak Saxena <dsaxena@plexity.net>"); 172 MODULE_DESCRIPTION("IXP4xx Network Processor Watchdog"); 173 MODULE_LICENSE("GPL"); 174