Linus Walleij | eca10ae | 2017-01-28 23:59:37 +0100 | [diff] [blame] | 1 | /* |
| 2 | * Watchdog driver for Cortina Systems Gemini SoC |
| 3 | * |
| 4 | * Copyright (C) 2017 Linus Walleij <linus.walleij@linaro.org> |
| 5 | * |
| 6 | * Inspired by the out-of-tree drivers from OpenWRT: |
| 7 | * Copyright (C) 2009 Paulius Zaleckas <paulius.zaleckas@teltonika.lt> |
| 8 | * |
| 9 | * This program is free software; you can redistribute it and/or modify |
| 10 | * it under the terms of the GNU General Public License version 2 as |
| 11 | * published by the Free Software Foundation. |
| 12 | */ |
| 13 | |
| 14 | #include <linux/bitops.h> |
| 15 | #include <linux/init.h> |
| 16 | #include <linux/interrupt.h> |
| 17 | #include <linux/io.h> |
| 18 | #include <linux/kernel.h> |
| 19 | #include <linux/module.h> |
| 20 | #include <linux/of_device.h> |
| 21 | #include <linux/platform_device.h> |
| 22 | #include <linux/slab.h> |
| 23 | #include <linux/watchdog.h> |
| 24 | |
| 25 | #define GEMINI_WDCOUNTER 0x0 |
| 26 | #define GEMINI_WDLOAD 0x4 |
| 27 | #define GEMINI_WDRESTART 0x8 |
| 28 | #define GEMINI_WDCR 0xC |
| 29 | |
| 30 | #define WDRESTART_MAGIC 0x5AB9 |
| 31 | |
| 32 | #define WDCR_CLOCK_5MHZ BIT(4) |
| 33 | #define WDCR_SYS_RST BIT(1) |
| 34 | #define WDCR_ENABLE BIT(0) |
| 35 | |
| 36 | #define WDT_CLOCK 5000000 /* 5 MHz */ |
| 37 | |
| 38 | struct gemini_wdt { |
| 39 | struct watchdog_device wdd; |
| 40 | struct device *dev; |
| 41 | void __iomem *base; |
| 42 | }; |
| 43 | |
| 44 | static inline |
| 45 | struct gemini_wdt *to_gemini_wdt(struct watchdog_device *wdd) |
| 46 | { |
| 47 | return container_of(wdd, struct gemini_wdt, wdd); |
| 48 | } |
| 49 | |
| 50 | static int gemini_wdt_start(struct watchdog_device *wdd) |
| 51 | { |
| 52 | struct gemini_wdt *gwdt = to_gemini_wdt(wdd); |
| 53 | |
| 54 | writel(wdd->timeout * WDT_CLOCK, gwdt->base + GEMINI_WDLOAD); |
| 55 | writel(WDRESTART_MAGIC, gwdt->base + GEMINI_WDRESTART); |
| 56 | /* set clock before enabling */ |
| 57 | writel(WDCR_CLOCK_5MHZ | WDCR_SYS_RST, |
| 58 | gwdt->base + GEMINI_WDCR); |
| 59 | writel(WDCR_CLOCK_5MHZ | WDCR_SYS_RST | WDCR_ENABLE, |
| 60 | gwdt->base + GEMINI_WDCR); |
| 61 | |
| 62 | return 0; |
| 63 | } |
| 64 | |
| 65 | static int gemini_wdt_stop(struct watchdog_device *wdd) |
| 66 | { |
| 67 | struct gemini_wdt *gwdt = to_gemini_wdt(wdd); |
| 68 | |
| 69 | writel(0, gwdt->base + GEMINI_WDCR); |
| 70 | |
| 71 | return 0; |
| 72 | } |
| 73 | |
| 74 | static int gemini_wdt_ping(struct watchdog_device *wdd) |
| 75 | { |
| 76 | struct gemini_wdt *gwdt = to_gemini_wdt(wdd); |
| 77 | |
| 78 | writel(WDRESTART_MAGIC, gwdt->base + GEMINI_WDRESTART); |
| 79 | |
| 80 | return 0; |
| 81 | } |
| 82 | |
| 83 | static int gemini_wdt_set_timeout(struct watchdog_device *wdd, |
| 84 | unsigned int timeout) |
| 85 | { |
| 86 | wdd->timeout = timeout; |
| 87 | if (watchdog_active(wdd)) |
| 88 | gemini_wdt_start(wdd); |
| 89 | |
| 90 | return 0; |
| 91 | } |
| 92 | |
| 93 | static irqreturn_t gemini_wdt_interrupt(int irq, void *data) |
| 94 | { |
| 95 | struct gemini_wdt *gwdt = data; |
| 96 | |
| 97 | watchdog_notify_pretimeout(&gwdt->wdd); |
| 98 | |
| 99 | return IRQ_HANDLED; |
| 100 | } |
| 101 | |
| 102 | static const struct watchdog_ops gemini_wdt_ops = { |
| 103 | .start = gemini_wdt_start, |
| 104 | .stop = gemini_wdt_stop, |
| 105 | .ping = gemini_wdt_ping, |
| 106 | .set_timeout = gemini_wdt_set_timeout, |
| 107 | .owner = THIS_MODULE, |
| 108 | }; |
| 109 | |
| 110 | static const struct watchdog_info gemini_wdt_info = { |
| 111 | .options = WDIOF_KEEPALIVEPING |
| 112 | | WDIOF_MAGICCLOSE |
| 113 | | WDIOF_SETTIMEOUT, |
| 114 | .identity = KBUILD_MODNAME, |
| 115 | }; |
| 116 | |
| 117 | |
| 118 | static int gemini_wdt_probe(struct platform_device *pdev) |
| 119 | { |
| 120 | struct device *dev = &pdev->dev; |
| 121 | struct resource *res; |
| 122 | struct gemini_wdt *gwdt; |
| 123 | unsigned int reg; |
| 124 | int irq; |
| 125 | int ret; |
| 126 | |
| 127 | gwdt = devm_kzalloc(dev, sizeof(*gwdt), GFP_KERNEL); |
| 128 | if (!gwdt) |
| 129 | return -ENOMEM; |
| 130 | |
| 131 | res = platform_get_resource(pdev, IORESOURCE_MEM, 0); |
| 132 | gwdt->base = devm_ioremap_resource(dev, res); |
| 133 | if (IS_ERR(gwdt->base)) |
| 134 | return PTR_ERR(gwdt->base); |
| 135 | |
| 136 | irq = platform_get_irq(pdev, 0); |
| 137 | if (!irq) |
| 138 | return -EINVAL; |
| 139 | |
| 140 | gwdt->dev = dev; |
| 141 | gwdt->wdd.info = &gemini_wdt_info; |
| 142 | gwdt->wdd.ops = &gemini_wdt_ops; |
| 143 | gwdt->wdd.min_timeout = 1; |
| 144 | gwdt->wdd.max_timeout = 0xFFFFFFFF / WDT_CLOCK; |
| 145 | gwdt->wdd.parent = dev; |
| 146 | |
| 147 | /* |
| 148 | * If 'timeout-sec' unspecified in devicetree, assume a 13 second |
| 149 | * default. |
| 150 | */ |
| 151 | gwdt->wdd.timeout = 13U; |
| 152 | watchdog_init_timeout(&gwdt->wdd, 0, dev); |
| 153 | |
| 154 | reg = readw(gwdt->base + GEMINI_WDCR); |
| 155 | if (reg & WDCR_ENABLE) { |
| 156 | /* Watchdog was enabled by the bootloader, disable it. */ |
| 157 | reg &= ~WDCR_ENABLE; |
| 158 | writel(reg, gwdt->base + GEMINI_WDCR); |
| 159 | } |
| 160 | |
| 161 | ret = devm_request_irq(dev, irq, gemini_wdt_interrupt, 0, |
| 162 | "watchdog bark", gwdt); |
| 163 | if (ret) |
| 164 | return ret; |
| 165 | |
| 166 | ret = devm_watchdog_register_device(dev, &gwdt->wdd); |
| 167 | if (ret) { |
| 168 | dev_err(&pdev->dev, "failed to register watchdog\n"); |
| 169 | return ret; |
| 170 | } |
| 171 | |
| 172 | /* Set up platform driver data */ |
| 173 | platform_set_drvdata(pdev, gwdt); |
| 174 | dev_info(dev, "Gemini watchdog driver enabled\n"); |
| 175 | |
| 176 | return 0; |
| 177 | } |
| 178 | |
| 179 | static int __maybe_unused gemini_wdt_suspend(struct device *dev) |
| 180 | { |
| 181 | struct gemini_wdt *gwdt = dev_get_drvdata(dev); |
| 182 | unsigned int reg; |
| 183 | |
| 184 | reg = readw(gwdt->base + GEMINI_WDCR); |
| 185 | reg &= ~WDCR_ENABLE; |
| 186 | writel(reg, gwdt->base + GEMINI_WDCR); |
| 187 | |
| 188 | return 0; |
| 189 | } |
| 190 | |
| 191 | static int __maybe_unused gemini_wdt_resume(struct device *dev) |
| 192 | { |
| 193 | struct gemini_wdt *gwdt = dev_get_drvdata(dev); |
| 194 | unsigned int reg; |
| 195 | |
| 196 | if (watchdog_active(&gwdt->wdd)) { |
| 197 | reg = readw(gwdt->base + GEMINI_WDCR); |
| 198 | reg |= WDCR_ENABLE; |
| 199 | writel(reg, gwdt->base + GEMINI_WDCR); |
| 200 | } |
| 201 | |
| 202 | return 0; |
| 203 | } |
| 204 | |
| 205 | static const struct dev_pm_ops gemini_wdt_dev_pm_ops = { |
| 206 | SET_SYSTEM_SLEEP_PM_OPS(gemini_wdt_suspend, |
| 207 | gemini_wdt_resume) |
| 208 | }; |
| 209 | |
| 210 | #ifdef CONFIG_OF |
| 211 | static const struct of_device_id gemini_wdt_match[] = { |
| 212 | { .compatible = "cortina,gemini-watchdog" }, |
| 213 | {}, |
| 214 | }; |
| 215 | MODULE_DEVICE_TABLE(of, gemini_wdt_match); |
| 216 | #endif |
| 217 | |
| 218 | static struct platform_driver gemini_wdt_driver = { |
| 219 | .probe = gemini_wdt_probe, |
| 220 | .driver = { |
| 221 | .name = "gemini-wdt", |
| 222 | .of_match_table = of_match_ptr(gemini_wdt_match), |
| 223 | .pm = &gemini_wdt_dev_pm_ops, |
| 224 | }, |
| 225 | }; |
| 226 | module_platform_driver(gemini_wdt_driver); |
| 227 | MODULE_AUTHOR("Linus Walleij"); |
| 228 | MODULE_DESCRIPTION("Watchdog driver for Gemini"); |
| 229 | MODULE_LICENSE("GPL"); |