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189 lines
4.5 KiB
189 lines
4.5 KiB
// SPDX-License-Identifier: GPL-2.0-only |
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/* |
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* Ralink MT7621/MT7628 built-in hardware watchdog timer |
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* |
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* Copyright (C) 2014 John Crispin <[email protected]> |
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* |
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* This driver was based on: drivers/watchdog/rt2880_wdt.c |
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*/ |
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#include <linux/clk.h> |
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#include <linux/reset.h> |
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#include <linux/module.h> |
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#include <linux/kernel.h> |
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#include <linux/watchdog.h> |
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#include <linux/moduleparam.h> |
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#include <linux/platform_device.h> |
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#include <linux/mod_devicetable.h> |
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#include <asm/mach-ralink/ralink_regs.h> |
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#define SYSC_RSTSTAT 0x38 |
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#define WDT_RST_CAUSE BIT(1) |
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#define RALINK_WDT_TIMEOUT 30 |
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#define TIMER_REG_TMRSTAT 0x00 |
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#define TIMER_REG_TMR1LOAD 0x24 |
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#define TIMER_REG_TMR1CTL 0x20 |
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#define TMR1CTL_ENABLE BIT(7) |
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#define TMR1CTL_RESTART BIT(9) |
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#define TMR1CTL_PRESCALE_SHIFT 16 |
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static void __iomem *mt7621_wdt_base; |
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static struct reset_control *mt7621_wdt_reset; |
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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 inline void rt_wdt_w32(unsigned reg, u32 val) |
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{ |
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iowrite32(val, mt7621_wdt_base + reg); |
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} |
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static inline u32 rt_wdt_r32(unsigned reg) |
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{ |
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return ioread32(mt7621_wdt_base + reg); |
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} |
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static int mt7621_wdt_ping(struct watchdog_device *w) |
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{ |
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rt_wdt_w32(TIMER_REG_TMRSTAT, TMR1CTL_RESTART); |
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return 0; |
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} |
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static int mt7621_wdt_set_timeout(struct watchdog_device *w, unsigned int t) |
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{ |
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w->timeout = t; |
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rt_wdt_w32(TIMER_REG_TMR1LOAD, t * 1000); |
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mt7621_wdt_ping(w); |
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return 0; |
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} |
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static int mt7621_wdt_start(struct watchdog_device *w) |
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{ |
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u32 t; |
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/* set the prescaler to 1ms == 1000us */ |
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rt_wdt_w32(TIMER_REG_TMR1CTL, 1000 << TMR1CTL_PRESCALE_SHIFT); |
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mt7621_wdt_set_timeout(w, w->timeout); |
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t = rt_wdt_r32(TIMER_REG_TMR1CTL); |
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t |= TMR1CTL_ENABLE; |
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rt_wdt_w32(TIMER_REG_TMR1CTL, t); |
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return 0; |
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} |
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static int mt7621_wdt_stop(struct watchdog_device *w) |
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{ |
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u32 t; |
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mt7621_wdt_ping(w); |
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t = rt_wdt_r32(TIMER_REG_TMR1CTL); |
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t &= ~TMR1CTL_ENABLE; |
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rt_wdt_w32(TIMER_REG_TMR1CTL, t); |
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return 0; |
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} |
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static int mt7621_wdt_bootcause(void) |
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{ |
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if (rt_sysc_r32(SYSC_RSTSTAT) & WDT_RST_CAUSE) |
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return WDIOF_CARDRESET; |
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return 0; |
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} |
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static int mt7621_wdt_is_running(struct watchdog_device *w) |
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{ |
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return !!(rt_wdt_r32(TIMER_REG_TMR1CTL) & TMR1CTL_ENABLE); |
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} |
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static const struct watchdog_info mt7621_wdt_info = { |
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.identity = "Mediatek Watchdog", |
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.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE, |
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}; |
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static const struct watchdog_ops mt7621_wdt_ops = { |
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.owner = THIS_MODULE, |
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.start = mt7621_wdt_start, |
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.stop = mt7621_wdt_stop, |
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.ping = mt7621_wdt_ping, |
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.set_timeout = mt7621_wdt_set_timeout, |
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}; |
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static struct watchdog_device mt7621_wdt_dev = { |
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.info = &mt7621_wdt_info, |
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.ops = &mt7621_wdt_ops, |
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.min_timeout = 1, |
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.max_timeout = 0xfffful / 1000, |
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}; |
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static int mt7621_wdt_probe(struct platform_device *pdev) |
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{ |
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struct device *dev = &pdev->dev; |
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mt7621_wdt_base = devm_platform_ioremap_resource(pdev, 0); |
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if (IS_ERR(mt7621_wdt_base)) |
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return PTR_ERR(mt7621_wdt_base); |
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mt7621_wdt_reset = devm_reset_control_get_exclusive(dev, NULL); |
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if (!IS_ERR(mt7621_wdt_reset)) |
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reset_control_deassert(mt7621_wdt_reset); |
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mt7621_wdt_dev.bootstatus = mt7621_wdt_bootcause(); |
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watchdog_init_timeout(&mt7621_wdt_dev, mt7621_wdt_dev.max_timeout, |
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dev); |
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watchdog_set_nowayout(&mt7621_wdt_dev, nowayout); |
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if (mt7621_wdt_is_running(&mt7621_wdt_dev)) { |
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/* |
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* Make sure to apply timeout from watchdog core, taking |
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* the prescaler of this driver here into account (the |
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* boot loader might be using a different prescaler). |
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* |
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* To avoid spurious resets because of different scaling, |
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* we first disable the watchdog, set the new prescaler |
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* and timeout, and then re-enable the watchdog. |
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*/ |
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mt7621_wdt_stop(&mt7621_wdt_dev); |
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mt7621_wdt_start(&mt7621_wdt_dev); |
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set_bit(WDOG_HW_RUNNING, &mt7621_wdt_dev.status); |
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} |
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return devm_watchdog_register_device(dev, &mt7621_wdt_dev); |
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} |
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static void mt7621_wdt_shutdown(struct platform_device *pdev) |
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{ |
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mt7621_wdt_stop(&mt7621_wdt_dev); |
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} |
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static const struct of_device_id mt7621_wdt_match[] = { |
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{ .compatible = "mediatek,mt7621-wdt" }, |
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{}, |
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}; |
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MODULE_DEVICE_TABLE(of, mt7621_wdt_match); |
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static struct platform_driver mt7621_wdt_driver = { |
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.probe = mt7621_wdt_probe, |
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.shutdown = mt7621_wdt_shutdown, |
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.driver = { |
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.name = KBUILD_MODNAME, |
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.of_match_table = mt7621_wdt_match, |
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}, |
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}; |
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module_platform_driver(mt7621_wdt_driver); |
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MODULE_DESCRIPTION("MediaTek MT762x hardware watchdog driver"); |
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MODULE_AUTHOR("John Crispin <[email protected]"); |
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MODULE_LICENSE("GPL v2");
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