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Release 4.14 drivers/watchdog/gemini_wdt.c

Directory: drivers/watchdog
/*
 * 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); }

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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; }

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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; }

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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; }

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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; }

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static irqreturn_t gemini_wdt_interrupt(int irq, void *data) { struct gemini_wdt *gwdt = data; watchdog_notify_pretimeout(&gwdt->wdd); return IRQ_HANDLED; }

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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; }

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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; }

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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; }

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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");

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Directory: drivers/watchdog
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