164 строки
3.8 KiB
C
164 строки
3.8 KiB
C
// SPDX-License-Identifier: GPL-2.0+
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/*
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* Watchdog driver for Conexant Digicolor
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*
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* Copyright (C) 2015 Paradox Innovation Ltd.
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*
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*/
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#include <linux/types.h>
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#include <linux/module.h>
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#include <linux/io.h>
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#include <linux/delay.h>
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#include <linux/clk.h>
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#include <linux/watchdog.h>
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#include <linux/platform_device.h>
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#include <linux/of_address.h>
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#define TIMER_A_CONTROL 0
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#define TIMER_A_COUNT 4
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#define TIMER_A_ENABLE_COUNT BIT(0)
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#define TIMER_A_ENABLE_WATCHDOG BIT(1)
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struct dc_wdt {
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void __iomem *base;
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struct clk *clk;
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spinlock_t lock;
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};
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static unsigned timeout;
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module_param(timeout, uint, 0);
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MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds");
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static void dc_wdt_set(struct dc_wdt *wdt, u32 ticks)
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{
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unsigned long flags;
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spin_lock_irqsave(&wdt->lock, flags);
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writel_relaxed(0, wdt->base + TIMER_A_CONTROL);
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writel_relaxed(ticks, wdt->base + TIMER_A_COUNT);
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writel_relaxed(TIMER_A_ENABLE_COUNT | TIMER_A_ENABLE_WATCHDOG,
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wdt->base + TIMER_A_CONTROL);
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spin_unlock_irqrestore(&wdt->lock, flags);
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}
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static int dc_wdt_restart(struct watchdog_device *wdog, unsigned long action,
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void *data)
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{
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struct dc_wdt *wdt = watchdog_get_drvdata(wdog);
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dc_wdt_set(wdt, 1);
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/* wait for reset to assert... */
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mdelay(500);
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return 0;
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}
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static int dc_wdt_start(struct watchdog_device *wdog)
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{
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struct dc_wdt *wdt = watchdog_get_drvdata(wdog);
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dc_wdt_set(wdt, wdog->timeout * clk_get_rate(wdt->clk));
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return 0;
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}
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static int dc_wdt_stop(struct watchdog_device *wdog)
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{
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struct dc_wdt *wdt = watchdog_get_drvdata(wdog);
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writel_relaxed(0, wdt->base + TIMER_A_CONTROL);
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return 0;
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}
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static int dc_wdt_set_timeout(struct watchdog_device *wdog, unsigned int t)
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{
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struct dc_wdt *wdt = watchdog_get_drvdata(wdog);
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dc_wdt_set(wdt, t * clk_get_rate(wdt->clk));
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wdog->timeout = t;
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return 0;
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}
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static unsigned int dc_wdt_get_timeleft(struct watchdog_device *wdog)
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{
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struct dc_wdt *wdt = watchdog_get_drvdata(wdog);
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uint32_t count = readl_relaxed(wdt->base + TIMER_A_COUNT);
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return count / clk_get_rate(wdt->clk);
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}
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static const struct watchdog_ops dc_wdt_ops = {
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.owner = THIS_MODULE,
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.start = dc_wdt_start,
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.stop = dc_wdt_stop,
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.set_timeout = dc_wdt_set_timeout,
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.get_timeleft = dc_wdt_get_timeleft,
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.restart = dc_wdt_restart,
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};
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static const struct watchdog_info dc_wdt_info = {
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.options = WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE
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| WDIOF_KEEPALIVEPING,
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.identity = "Conexant Digicolor Watchdog",
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};
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static struct watchdog_device dc_wdt_wdd = {
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.info = &dc_wdt_info,
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.ops = &dc_wdt_ops,
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.min_timeout = 1,
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};
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static int dc_wdt_probe(struct platform_device *pdev)
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{
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struct device *dev = &pdev->dev;
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struct dc_wdt *wdt;
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wdt = devm_kzalloc(dev, sizeof(struct dc_wdt), GFP_KERNEL);
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if (!wdt)
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return -ENOMEM;
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wdt->base = devm_platform_ioremap_resource(pdev, 0);
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if (IS_ERR(wdt->base))
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return PTR_ERR(wdt->base);
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wdt->clk = devm_clk_get(dev, NULL);
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if (IS_ERR(wdt->clk))
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return PTR_ERR(wdt->clk);
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dc_wdt_wdd.max_timeout = U32_MAX / clk_get_rate(wdt->clk);
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dc_wdt_wdd.timeout = dc_wdt_wdd.max_timeout;
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dc_wdt_wdd.parent = dev;
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spin_lock_init(&wdt->lock);
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watchdog_set_drvdata(&dc_wdt_wdd, wdt);
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watchdog_set_restart_priority(&dc_wdt_wdd, 128);
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watchdog_init_timeout(&dc_wdt_wdd, timeout, dev);
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watchdog_stop_on_reboot(&dc_wdt_wdd);
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return devm_watchdog_register_device(dev, &dc_wdt_wdd);
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}
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static const struct of_device_id dc_wdt_of_match[] = {
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{ .compatible = "cnxt,cx92755-wdt", },
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{},
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};
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MODULE_DEVICE_TABLE(of, dc_wdt_of_match);
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static struct platform_driver dc_wdt_driver = {
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.probe = dc_wdt_probe,
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.driver = {
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.name = "digicolor-wdt",
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.of_match_table = dc_wdt_of_match,
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},
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};
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module_platform_driver(dc_wdt_driver);
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MODULE_AUTHOR("Baruch Siach <baruch@tkos.co.il>");
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MODULE_DESCRIPTION("Driver for Conexant Digicolor watchdog timer");
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MODULE_LICENSE("GPL");
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