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209 lines
4.8 KiB
209 lines
4.8 KiB
// SPDX-License-Identifier: GPL-2.0+ |
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/* |
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* Copyright (C) 2015 Mans Rullgard <[email protected]> |
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* SMP86xx/SMP87xx Watchdog driver |
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*/ |
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#include <linux/bitops.h> |
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#include <linux/clk.h> |
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#include <linux/delay.h> |
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#include <linux/io.h> |
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#include <linux/kernel.h> |
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#include <linux/module.h> |
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#include <linux/moduleparam.h> |
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#include <linux/mod_devicetable.h> |
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#include <linux/platform_device.h> |
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#include <linux/watchdog.h> |
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#define DEFAULT_TIMEOUT 30 |
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static bool nowayout = WATCHDOG_NOWAYOUT; |
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module_param(nowayout, bool, 0); |
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MODULE_PARM_DESC(nowayout, |
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"Watchdog cannot be stopped once started (default=" |
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__MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); |
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static unsigned int timeout; |
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module_param(timeout, int, 0); |
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MODULE_PARM_DESC(timeout, "Watchdog timeout"); |
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/* |
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* Counter counts down from programmed value. Reset asserts when |
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* the counter reaches 1. |
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*/ |
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#define WD_COUNTER 0 |
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#define WD_CONFIG 4 |
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#define WD_CONFIG_XTAL_IN BIT(0) |
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#define WD_CONFIG_DISABLE BIT(31) |
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struct tangox_wdt_device { |
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struct watchdog_device wdt; |
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void __iomem *base; |
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unsigned long clk_rate; |
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struct clk *clk; |
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}; |
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static int tangox_wdt_set_timeout(struct watchdog_device *wdt, |
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unsigned int new_timeout) |
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{ |
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wdt->timeout = new_timeout; |
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return 0; |
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} |
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static int tangox_wdt_start(struct watchdog_device *wdt) |
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{ |
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struct tangox_wdt_device *dev = watchdog_get_drvdata(wdt); |
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u32 ticks; |
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ticks = 1 + wdt->timeout * dev->clk_rate; |
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writel(ticks, dev->base + WD_COUNTER); |
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return 0; |
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} |
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static int tangox_wdt_stop(struct watchdog_device *wdt) |
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{ |
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struct tangox_wdt_device *dev = watchdog_get_drvdata(wdt); |
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writel(0, dev->base + WD_COUNTER); |
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return 0; |
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} |
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static unsigned int tangox_wdt_get_timeleft(struct watchdog_device *wdt) |
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{ |
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struct tangox_wdt_device *dev = watchdog_get_drvdata(wdt); |
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u32 count; |
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count = readl(dev->base + WD_COUNTER); |
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if (!count) |
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return 0; |
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return (count - 1) / dev->clk_rate; |
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} |
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static const struct watchdog_info tangox_wdt_info = { |
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.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE, |
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.identity = "tangox watchdog", |
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}; |
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static int tangox_wdt_restart(struct watchdog_device *wdt, |
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unsigned long action, void *data) |
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{ |
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struct tangox_wdt_device *dev = watchdog_get_drvdata(wdt); |
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writel(1, dev->base + WD_COUNTER); |
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return 0; |
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} |
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static const struct watchdog_ops tangox_wdt_ops = { |
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.start = tangox_wdt_start, |
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.stop = tangox_wdt_stop, |
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.set_timeout = tangox_wdt_set_timeout, |
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.get_timeleft = tangox_wdt_get_timeleft, |
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.restart = tangox_wdt_restart, |
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}; |
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static void tangox_clk_disable_unprepare(void *data) |
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{ |
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clk_disable_unprepare(data); |
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} |
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static int tangox_wdt_probe(struct platform_device *pdev) |
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{ |
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struct tangox_wdt_device *dev; |
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u32 config; |
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int err; |
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dev = devm_kzalloc(&pdev->dev, sizeof(*dev), GFP_KERNEL); |
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if (!dev) |
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return -ENOMEM; |
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dev->base = devm_platform_ioremap_resource(pdev, 0); |
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if (IS_ERR(dev->base)) |
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return PTR_ERR(dev->base); |
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dev->clk = devm_clk_get(&pdev->dev, NULL); |
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if (IS_ERR(dev->clk)) |
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return PTR_ERR(dev->clk); |
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err = clk_prepare_enable(dev->clk); |
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if (err) |
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return err; |
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err = devm_add_action_or_reset(&pdev->dev, |
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tangox_clk_disable_unprepare, dev->clk); |
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if (err) |
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return err; |
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dev->clk_rate = clk_get_rate(dev->clk); |
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if (!dev->clk_rate) |
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return -EINVAL; |
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dev->wdt.parent = &pdev->dev; |
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dev->wdt.info = &tangox_wdt_info; |
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dev->wdt.ops = &tangox_wdt_ops; |
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dev->wdt.timeout = DEFAULT_TIMEOUT; |
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dev->wdt.min_timeout = 1; |
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dev->wdt.max_hw_heartbeat_ms = (U32_MAX - 1) / dev->clk_rate; |
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watchdog_init_timeout(&dev->wdt, timeout, &pdev->dev); |
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watchdog_set_nowayout(&dev->wdt, nowayout); |
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watchdog_set_drvdata(&dev->wdt, dev); |
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/* |
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* Deactivate counter if disable bit is set to avoid |
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* accidental reset. |
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*/ |
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config = readl(dev->base + WD_CONFIG); |
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if (config & WD_CONFIG_DISABLE) |
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writel(0, dev->base + WD_COUNTER); |
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writel(WD_CONFIG_XTAL_IN, dev->base + WD_CONFIG); |
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/* |
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* Mark as active and restart with configured timeout if |
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* already running. |
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*/ |
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if (readl(dev->base + WD_COUNTER)) { |
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set_bit(WDOG_HW_RUNNING, &dev->wdt.status); |
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tangox_wdt_start(&dev->wdt); |
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} |
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watchdog_set_restart_priority(&dev->wdt, 128); |
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watchdog_stop_on_unregister(&dev->wdt); |
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err = devm_watchdog_register_device(&pdev->dev, &dev->wdt); |
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if (err) |
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return err; |
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platform_set_drvdata(pdev, dev); |
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dev_info(&pdev->dev, "SMP86xx/SMP87xx watchdog registered\n"); |
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return 0; |
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} |
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static const struct of_device_id tangox_wdt_dt_ids[] = { |
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{ .compatible = "sigma,smp8642-wdt" }, |
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{ .compatible = "sigma,smp8759-wdt" }, |
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{ } |
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}; |
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MODULE_DEVICE_TABLE(of, tangox_wdt_dt_ids); |
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static struct platform_driver tangox_wdt_driver = { |
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.probe = tangox_wdt_probe, |
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.driver = { |
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.name = "tangox-wdt", |
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.of_match_table = tangox_wdt_dt_ids, |
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}, |
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}; |
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module_platform_driver(tangox_wdt_driver); |
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MODULE_AUTHOR("Mans Rullgard <[email protected]>"); |
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MODULE_DESCRIPTION("SMP86xx/SMP87xx Watchdog driver"); |
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MODULE_LICENSE("GPL");
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