diff options
Diffstat (limited to 'drivers/watchdog/gemini_wdt.c')
| -rw-r--r-- | drivers/watchdog/gemini_wdt.c | 229 |
1 files changed, 229 insertions, 0 deletions
diff --git a/drivers/watchdog/gemini_wdt.c b/drivers/watchdog/gemini_wdt.c new file mode 100644 index 000000000000..8155aa619e4c --- /dev/null +++ b/drivers/watchdog/gemini_wdt.c @@ -0,0 +1,229 @@ +/* + * Watchdog driver for Cortina Systems Gemini SoC + * + * Copyright (C) 2017 Linus Walleij <linus.walleij@linaro.org> + * + * Inspired by the out-of-tree drivers from OpenWRT: + * Copyright (C) 2009 Paulius Zaleckas <paulius.zaleckas@teltonika.lt> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + */ + +#include <linux/bitops.h> +#include <linux/init.h> +#include <linux/interrupt.h> +#include <linux/io.h> +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/of_device.h> +#include <linux/platform_device.h> +#include <linux/slab.h> +#include <linux/watchdog.h> + +#define GEMINI_WDCOUNTER 0x0 +#define GEMINI_WDLOAD 0x4 +#define GEMINI_WDRESTART 0x8 +#define GEMINI_WDCR 0xC + +#define WDRESTART_MAGIC 0x5AB9 + +#define WDCR_CLOCK_5MHZ BIT(4) +#define WDCR_SYS_RST BIT(1) +#define WDCR_ENABLE BIT(0) + +#define WDT_CLOCK 5000000 /* 5 MHz */ + +struct gemini_wdt { + struct watchdog_device wdd; + struct device *dev; + void __iomem *base; +}; + +static inline +struct gemini_wdt *to_gemini_wdt(struct watchdog_device *wdd) +{ + return container_of(wdd, struct gemini_wdt, wdd); +} + +static int gemini_wdt_start(struct watchdog_device *wdd) +{ + struct gemini_wdt *gwdt = to_gemini_wdt(wdd); + + writel(wdd->timeout * WDT_CLOCK, gwdt->base + GEMINI_WDLOAD); + writel(WDRESTART_MAGIC, gwdt->base + GEMINI_WDRESTART); + /* set clock before enabling */ + writel(WDCR_CLOCK_5MHZ | WDCR_SYS_RST, + gwdt->base + GEMINI_WDCR); + writel(WDCR_CLOCK_5MHZ | WDCR_SYS_RST | WDCR_ENABLE, + gwdt->base + GEMINI_WDCR); + + return 0; +} + +static int gemini_wdt_stop(struct watchdog_device *wdd) +{ + struct gemini_wdt *gwdt = to_gemini_wdt(wdd); + + writel(0, gwdt->base + GEMINI_WDCR); + + return 0; +} + +static int gemini_wdt_ping(struct watchdog_device *wdd) +{ + struct gemini_wdt *gwdt = to_gemini_wdt(wdd); + + writel(WDRESTART_MAGIC, gwdt->base + GEMINI_WDRESTART); + + return 0; +} + +static int gemini_wdt_set_timeout(struct watchdog_device *wdd, + unsigned int timeout) +{ + wdd->timeout = timeout; + if (watchdog_active(wdd)) + gemini_wdt_start(wdd); + + return 0; +} + +static irqreturn_t gemini_wdt_interrupt(int irq, void *data) +{ + struct gemini_wdt *gwdt = data; + + watchdog_notify_pretimeout(&gwdt->wdd); + + return IRQ_HANDLED; +} + +static const struct watchdog_ops gemini_wdt_ops = { + .start = gemini_wdt_start, + .stop = gemini_wdt_stop, + .ping = gemini_wdt_ping, + .set_timeout = gemini_wdt_set_timeout, + .owner = THIS_MODULE, +}; + +static const struct watchdog_info gemini_wdt_info = { + .options = WDIOF_KEEPALIVEPING + | WDIOF_MAGICCLOSE + | WDIOF_SETTIMEOUT, + .identity = KBUILD_MODNAME, +}; + + +static int gemini_wdt_probe(struct platform_device *pdev) +{ + struct device *dev = &pdev->dev; + struct resource *res; + struct gemini_wdt *gwdt; + unsigned int reg; + int irq; + int ret; + + gwdt = devm_kzalloc(dev, sizeof(*gwdt), GFP_KERNEL); + if (!gwdt) + return -ENOMEM; + + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); + gwdt->base = devm_ioremap_resource(dev, res); + if (IS_ERR(gwdt->base)) + return PTR_ERR(gwdt->base); + + irq = platform_get_irq(pdev, 0); + if (!irq) + return -EINVAL; + + gwdt->dev = dev; + gwdt->wdd.info = &gemini_wdt_info; + gwdt->wdd.ops = &gemini_wdt_ops; + gwdt->wdd.min_timeout = 1; + gwdt->wdd.max_timeout = 0xFFFFFFFF / WDT_CLOCK; + gwdt->wdd.parent = dev; + + /* + * If 'timeout-sec' unspecified in devicetree, assume a 13 second + * default. + */ + gwdt->wdd.timeout = 13U; + watchdog_init_timeout(&gwdt->wdd, 0, dev); + + reg = readw(gwdt->base + GEMINI_WDCR); + if (reg & WDCR_ENABLE) { + /* Watchdog was enabled by the bootloader, disable it. */ + reg &= ~WDCR_ENABLE; + writel(reg, gwdt->base + GEMINI_WDCR); + } + + ret = devm_request_irq(dev, irq, gemini_wdt_interrupt, 0, + "watchdog bark", gwdt); + if (ret) + return ret; + + ret = devm_watchdog_register_device(dev, &gwdt->wdd); + if (ret) { + dev_err(&pdev->dev, "failed to register watchdog\n"); + return ret; + } + + /* Set up platform driver data */ + platform_set_drvdata(pdev, gwdt); + dev_info(dev, "Gemini watchdog driver enabled\n"); + + return 0; +} + +static int __maybe_unused gemini_wdt_suspend(struct device *dev) +{ + struct gemini_wdt *gwdt = dev_get_drvdata(dev); + unsigned int reg; + + reg = readw(gwdt->base + GEMINI_WDCR); + reg &= ~WDCR_ENABLE; + writel(reg, gwdt->base + GEMINI_WDCR); + + return 0; +} + +static int __maybe_unused gemini_wdt_resume(struct device *dev) +{ + struct gemini_wdt *gwdt = dev_get_drvdata(dev); + unsigned int reg; + + if (watchdog_active(&gwdt->wdd)) { + reg = readw(gwdt->base + GEMINI_WDCR); + reg |= WDCR_ENABLE; + writel(reg, gwdt->base + GEMINI_WDCR); + } + + return 0; +} + +static const struct dev_pm_ops gemini_wdt_dev_pm_ops = { + SET_SYSTEM_SLEEP_PM_OPS(gemini_wdt_suspend, + gemini_wdt_resume) +}; + +#ifdef CONFIG_OF +static const struct of_device_id gemini_wdt_match[] = { + { .compatible = "cortina,gemini-watchdog" }, + {}, +}; +MODULE_DEVICE_TABLE(of, gemini_wdt_match); +#endif + +static struct platform_driver gemini_wdt_driver = { + .probe = gemini_wdt_probe, + .driver = { + .name = "gemini-wdt", + .of_match_table = of_match_ptr(gemini_wdt_match), + .pm = &gemini_wdt_dev_pm_ops, + }, +}; +module_platform_driver(gemini_wdt_driver); +MODULE_AUTHOR("Linus Walleij"); +MODULE_DESCRIPTION("Watchdog driver for Gemini"); +MODULE_LICENSE("GPL"); |