diff options
Diffstat (limited to 'drivers/watchdog/mt7621_wdt.c')
| -rw-r--r-- | drivers/watchdog/mt7621_wdt.c | 189 |
1 files changed, 189 insertions, 0 deletions
diff --git a/drivers/watchdog/mt7621_wdt.c b/drivers/watchdog/mt7621_wdt.c new file mode 100644 index 000000000..a8aa3522c --- /dev/null +++ b/drivers/watchdog/mt7621_wdt.c @@ -0,0 +1,189 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Ralink MT7621/MT7628 built-in hardware watchdog timer + * + * Copyright (C) 2014 John Crispin <john@phrozen.org> + * + * This driver was based on: drivers/watchdog/rt2880_wdt.c + */ + +#include <linux/clk.h> +#include <linux/reset.h> +#include <linux/module.h> +#include <linux/kernel.h> +#include <linux/watchdog.h> +#include <linux/moduleparam.h> +#include <linux/platform_device.h> +#include <linux/mod_devicetable.h> + +#include <asm/mach-ralink/ralink_regs.h> + +#define SYSC_RSTSTAT 0x38 +#define WDT_RST_CAUSE BIT(1) + +#define RALINK_WDT_TIMEOUT 30 + +#define TIMER_REG_TMRSTAT 0x00 +#define TIMER_REG_TMR1LOAD 0x24 +#define TIMER_REG_TMR1CTL 0x20 + +#define TMR1CTL_ENABLE BIT(7) +#define TMR1CTL_RESTART BIT(9) +#define TMR1CTL_PRESCALE_SHIFT 16 + +static void __iomem *mt7621_wdt_base; +static struct reset_control *mt7621_wdt_reset; + +static bool nowayout = WATCHDOG_NOWAYOUT; +module_param(nowayout, bool, 0); +MODULE_PARM_DESC(nowayout, + "Watchdog cannot be stopped once started (default=" + __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); + +static inline void rt_wdt_w32(unsigned reg, u32 val) +{ + iowrite32(val, mt7621_wdt_base + reg); +} + +static inline u32 rt_wdt_r32(unsigned reg) +{ + return ioread32(mt7621_wdt_base + reg); +} + +static int mt7621_wdt_ping(struct watchdog_device *w) +{ + rt_wdt_w32(TIMER_REG_TMRSTAT, TMR1CTL_RESTART); + + return 0; +} + +static int mt7621_wdt_set_timeout(struct watchdog_device *w, unsigned int t) +{ + w->timeout = t; + rt_wdt_w32(TIMER_REG_TMR1LOAD, t * 1000); + mt7621_wdt_ping(w); + + return 0; +} + +static int mt7621_wdt_start(struct watchdog_device *w) +{ + u32 t; + + /* set the prescaler to 1ms == 1000us */ + rt_wdt_w32(TIMER_REG_TMR1CTL, 1000 << TMR1CTL_PRESCALE_SHIFT); + + mt7621_wdt_set_timeout(w, w->timeout); + + t = rt_wdt_r32(TIMER_REG_TMR1CTL); + t |= TMR1CTL_ENABLE; + rt_wdt_w32(TIMER_REG_TMR1CTL, t); + + return 0; +} + +static int mt7621_wdt_stop(struct watchdog_device *w) +{ + u32 t; + + mt7621_wdt_ping(w); + + t = rt_wdt_r32(TIMER_REG_TMR1CTL); + t &= ~TMR1CTL_ENABLE; + rt_wdt_w32(TIMER_REG_TMR1CTL, t); + + return 0; +} + +static int mt7621_wdt_bootcause(void) +{ + if (rt_sysc_r32(SYSC_RSTSTAT) & WDT_RST_CAUSE) + return WDIOF_CARDRESET; + + return 0; +} + +static int mt7621_wdt_is_running(struct watchdog_device *w) +{ + return !!(rt_wdt_r32(TIMER_REG_TMR1CTL) & TMR1CTL_ENABLE); +} + +static const struct watchdog_info mt7621_wdt_info = { + .identity = "Mediatek Watchdog", + .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE, +}; + +static const struct watchdog_ops mt7621_wdt_ops = { + .owner = THIS_MODULE, + .start = mt7621_wdt_start, + .stop = mt7621_wdt_stop, + .ping = mt7621_wdt_ping, + .set_timeout = mt7621_wdt_set_timeout, +}; + +static struct watchdog_device mt7621_wdt_dev = { + .info = &mt7621_wdt_info, + .ops = &mt7621_wdt_ops, + .min_timeout = 1, + .max_timeout = 0xfffful / 1000, +}; + +static int mt7621_wdt_probe(struct platform_device *pdev) +{ + struct device *dev = &pdev->dev; + mt7621_wdt_base = devm_platform_ioremap_resource(pdev, 0); + if (IS_ERR(mt7621_wdt_base)) + return PTR_ERR(mt7621_wdt_base); + + mt7621_wdt_reset = devm_reset_control_get_exclusive(dev, NULL); + if (!IS_ERR(mt7621_wdt_reset)) + reset_control_deassert(mt7621_wdt_reset); + + mt7621_wdt_dev.bootstatus = mt7621_wdt_bootcause(); + + watchdog_init_timeout(&mt7621_wdt_dev, mt7621_wdt_dev.max_timeout, + dev); + watchdog_set_nowayout(&mt7621_wdt_dev, nowayout); + if (mt7621_wdt_is_running(&mt7621_wdt_dev)) { + /* + * Make sure to apply timeout from watchdog core, taking + * the prescaler of this driver here into account (the + * boot loader might be using a different prescaler). + * + * To avoid spurious resets because of different scaling, + * we first disable the watchdog, set the new prescaler + * and timeout, and then re-enable the watchdog. + */ + mt7621_wdt_stop(&mt7621_wdt_dev); + mt7621_wdt_start(&mt7621_wdt_dev); + set_bit(WDOG_HW_RUNNING, &mt7621_wdt_dev.status); + } + + return devm_watchdog_register_device(dev, &mt7621_wdt_dev); +} + +static void mt7621_wdt_shutdown(struct platform_device *pdev) +{ + mt7621_wdt_stop(&mt7621_wdt_dev); +} + +static const struct of_device_id mt7621_wdt_match[] = { + { .compatible = "mediatek,mt7621-wdt" }, + {}, +}; +MODULE_DEVICE_TABLE(of, mt7621_wdt_match); + +static struct platform_driver mt7621_wdt_driver = { + .probe = mt7621_wdt_probe, + .shutdown = mt7621_wdt_shutdown, + .driver = { + .name = KBUILD_MODNAME, + .of_match_table = mt7621_wdt_match, + }, +}; + +module_platform_driver(mt7621_wdt_driver); + +MODULE_DESCRIPTION("MediaTek MT762x hardware watchdog driver"); +MODULE_AUTHOR("John Crispin <john@phrozen.org"); +MODULE_LICENSE("GPL v2"); |