diff options
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/watchdog/Kconfig | 11 | ||||
| -rw-r--r-- | drivers/watchdog/Makefile | 1 | ||||
| -rw-r--r-- | drivers/watchdog/tegra_wdt.c | 302 |
3 files changed, 314 insertions, 0 deletions
diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig index 4b54a0faa167..ce9309152fdf 100644 --- a/drivers/watchdog/Kconfig +++ b/drivers/watchdog/Kconfig @@ -430,6 +430,17 @@ config SIRFSOC_WATCHDOG Support for CSR SiRFprimaII and SiRFatlasVI watchdog. When the watchdog triggers the system will be reset. +config TEGRA_WATCHDOG + tristate "Tegra watchdog" + depends on ARCH_TEGRA || COMPILE_TEST + select WATCHDOG_CORE + help + Say Y here to include support for the watchdog timer + embedded in NVIDIA Tegra SoCs. + + To compile this driver as a module, choose M here: the + module will be called tegra_wdt. + # AVR32 Architecture config AT32AP700X_WDT diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile index 985a66cda76f..1b5f3d5efad5 100644 --- a/drivers/watchdog/Makefile +++ b/drivers/watchdog/Makefile @@ -58,6 +58,7 @@ obj-$(CONFIG_BCM2835_WDT) += bcm2835_wdt.o obj-$(CONFIG_MOXART_WDT) += moxart_wdt.o obj-$(CONFIG_SIRFSOC_WATCHDOG) += sirfsoc_wdt.o obj-$(CONFIG_BCM_KONA_WDT) += bcm_kona_wdt.o +obj-$(CONFIG_TEGRA_WATCHDOG) += tegra_wdt.o # AVR32 Architecture obj-$(CONFIG_AT32AP700X_WDT) += at32ap700x_wdt.o diff --git a/drivers/watchdog/tegra_wdt.c b/drivers/watchdog/tegra_wdt.c new file mode 100644 index 000000000000..750e2a26cb12 --- /dev/null +++ b/drivers/watchdog/tegra_wdt.c @@ -0,0 +1,302 @@ +/* + * Copyright (c) 2014, NVIDIA CORPORATION. All rights reserved. + * + * This program is free software; you can redistribute it and/or modify it + * under the terms and conditions of the GNU General Public License, + * version 2, as published by the Free Software Foundation. + * + * This program is distributed in the hope it will be useful, but WITHOUT + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for + * more details. + */ + +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/interrupt.h> +#include <linux/io.h> +#include <linux/of.h> +#include <linux/platform_device.h> +#include <linux/watchdog.h> + +/* minimum and maximum watchdog trigger timeout, in seconds */ +#define MIN_WDT_TIMEOUT 1 +#define MAX_WDT_TIMEOUT 255 + +/* + * Base of the WDT registers, from the timer base address. There are + * actually 5 watchdogs that can be configured (by pairing with an available + * timer), at bases 0x100 + (WDT ID) * 0x20, where WDT ID is 0 through 4. + * This driver only configures the first watchdog (WDT ID 0). + */ +#define WDT_BASE 0x100 +#define WDT_ID 0 + +/* + * Register base of the timer that's selected for pairing with the watchdog. + * This driver arbitrarily uses timer 5, which is currently unused by + * other drivers (in particular, the Tegra clocksource driver). If this + * needs to change, take care that the new timer is not used by the + * clocksource driver. + */ +#define WDT_TIMER_BASE 0x60 +#define WDT_TIMER_ID 5 + +/* WDT registers */ +#define WDT_CFG 0x0 +#define WDT_CFG_PERIOD_SHIFT 4 +#define WDT_CFG_PERIOD_MASK 0xff +#define WDT_CFG_INT_EN (1 << 12) +#define WDT_CFG_PMC2CAR_RST_EN (1 << 15) +#define WDT_STS 0x4 +#define WDT_STS_COUNT_SHIFT 4 +#define WDT_STS_COUNT_MASK 0xff +#define WDT_STS_EXP_SHIFT 12 +#define WDT_STS_EXP_MASK 0x3 +#define WDT_CMD 0x8 +#define WDT_CMD_START_COUNTER (1 << 0) +#define WDT_CMD_DISABLE_COUNTER (1 << 1) +#define WDT_UNLOCK (0xc) +#define WDT_UNLOCK_PATTERN (0xc45a << 0) + +/* Timer registers */ +#define TIMER_PTV 0x0 +#define TIMER_EN (1 << 31) +#define TIMER_PERIODIC (1 << 30) + +struct tegra_wdt { + struct watchdog_device wdd; + void __iomem *wdt_regs; + void __iomem *tmr_regs; +}; + +#define WDT_HEARTBEAT 120 +static int heartbeat = WDT_HEARTBEAT; +module_param(heartbeat, int, 0); +MODULE_PARM_DESC(heartbeat, + "Watchdog heartbeats in seconds. (default = " + __MODULE_STRING(WDT_HEARTBEAT) ")"); + +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 int tegra_wdt_start(struct watchdog_device *wdd) +{ + struct tegra_wdt *wdt = watchdog_get_drvdata(wdd); + u32 val; + + /* + * This thing has a fixed 1MHz clock. Normally, we would set the + * period to 1 second by writing 1000000ul, but the watchdog system + * reset actually occurs on the 4th expiration of this counter, + * so we set the period to 1/4 of this amount. + */ + val = 1000000ul / 4; + val |= (TIMER_EN | TIMER_PERIODIC); + writel(val, wdt->tmr_regs + TIMER_PTV); + + /* + * Set number of periods and start counter. + * + * Interrupt handler is not required for user space + * WDT accesses, since the caller is responsible to ping the + * WDT to reset the counter before expiration, through ioctls. + */ + val = WDT_TIMER_ID | + (wdd->timeout << WDT_CFG_PERIOD_SHIFT) | + WDT_CFG_PMC2CAR_RST_EN; + writel(val, wdt->wdt_regs + WDT_CFG); + + writel(WDT_CMD_START_COUNTER, wdt->wdt_regs + WDT_CMD); + + return 0; +} + +static int tegra_wdt_stop(struct watchdog_device *wdd) +{ + struct tegra_wdt *wdt = watchdog_get_drvdata(wdd); + + writel(WDT_UNLOCK_PATTERN, wdt->wdt_regs + WDT_UNLOCK); + writel(WDT_CMD_DISABLE_COUNTER, wdt->wdt_regs + WDT_CMD); + writel(0, wdt->tmr_regs + TIMER_PTV); + + return 0; +} + +static int tegra_wdt_ping(struct watchdog_device *wdd) +{ + struct tegra_wdt *wdt = watchdog_get_drvdata(wdd); + + writel(WDT_CMD_START_COUNTER, wdt->wdt_regs + WDT_CMD); + + return 0; +} + +static int tegra_wdt_set_timeout(struct watchdog_device *wdd, + unsigned int timeout) +{ + wdd->timeout = timeout; + + if (watchdog_active(wdd)) + return tegra_wdt_start(wdd); + + return 0; +} + +static unsigned int tegra_wdt_get_timeleft(struct watchdog_device *wdd) +{ + struct tegra_wdt *wdt = watchdog_get_drvdata(wdd); + u32 val; + int count; + int exp; + + val = readl(wdt->wdt_regs + WDT_STS); + + /* Current countdown (from timeout) */ + count = (val >> WDT_STS_COUNT_SHIFT) & WDT_STS_COUNT_MASK; + + /* Number of expirations (we are waiting for the 4th expiration) */ + exp = (val >> WDT_STS_EXP_SHIFT) & WDT_STS_EXP_MASK; + + /* + * The entire thing is divided by 4 because we are ticking down 4 times + * faster due to needing to wait for the 4th expiration. + */ + return (((3 - exp) * wdd->timeout) + count) / 4; +} + +static const struct watchdog_info tegra_wdt_info = { + .options = WDIOF_SETTIMEOUT | + WDIOF_MAGICCLOSE | + WDIOF_KEEPALIVEPING, + .firmware_version = 0, + .identity = "Tegra Watchdog", +}; + +static struct watchdog_ops tegra_wdt_ops = { + .owner = THIS_MODULE, + .start = tegra_wdt_start, + .stop = tegra_wdt_stop, + .ping = tegra_wdt_ping, + .set_timeout = tegra_wdt_set_timeout, + .get_timeleft = tegra_wdt_get_timeleft, +}; + +static int tegra_wdt_probe(struct platform_device *pdev) +{ + struct watchdog_device *wdd; + struct tegra_wdt *wdt; + struct resource *res; + void __iomem *regs; + int ret; + + /* This is the timer base. */ + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); + regs = devm_ioremap_resource(&pdev->dev, res); + if (IS_ERR(regs)) + return PTR_ERR(regs); + + /* + * Allocate our watchdog driver data, which has the + * struct watchdog_device nested within it. + */ + wdt = devm_kzalloc(&pdev->dev, sizeof(*wdt), GFP_KERNEL); + if (!wdt) + return -ENOMEM; + + /* Initialize struct tegra_wdt. */ + wdt->wdt_regs = regs + WDT_BASE; + wdt->tmr_regs = regs + WDT_TIMER_BASE; + + /* Initialize struct watchdog_device. */ + wdd = &wdt->wdd; + wdd->timeout = heartbeat; + wdd->info = &tegra_wdt_info; + wdd->ops = &tegra_wdt_ops; + wdd->min_timeout = MIN_WDT_TIMEOUT; + wdd->max_timeout = MAX_WDT_TIMEOUT; + + watchdog_set_drvdata(wdd, wdt); + + watchdog_set_nowayout(wdd, nowayout); + + ret = watchdog_register_device(wdd); + if (ret) { + dev_err(&pdev->dev, + "failed to register watchdog device\n"); + return ret; + } + + platform_set_drvdata(pdev, wdt); + + dev_info(&pdev->dev, + "initialized (heartbeat = %d sec, nowayout = %d)\n", + heartbeat, nowayout); + + return 0; +} + +static int tegra_wdt_remove(struct platform_device *pdev) +{ + struct tegra_wdt *wdt = platform_get_drvdata(pdev); + + tegra_wdt_stop(&wdt->wdd); + + watchdog_unregister_device(&wdt->wdd); + + dev_info(&pdev->dev, "removed wdt\n"); + + return 0; +} + +#ifdef CONFIG_PM_SLEEP +static int tegra_wdt_runtime_suspend(struct device *dev) +{ + struct tegra_wdt *wdt = dev_get_drvdata(dev); + + if (watchdog_active(&wdt->wdd)) + tegra_wdt_stop(&wdt->wdd); + + return 0; +} + +static int tegra_wdt_runtime_resume(struct device *dev) +{ + struct tegra_wdt *wdt = dev_get_drvdata(dev); + + if (watchdog_active(&wdt->wdd)) + tegra_wdt_start(&wdt->wdd); + + return 0; +} +#endif + +static const struct of_device_id tegra_wdt_of_match[] = { + { .compatible = "nvidia,tegra30-timer", }, + { }, +}; +MODULE_DEVICE_TABLE(of, tegra_wdt_of_match); + +static const struct dev_pm_ops tegra_wdt_pm_ops = { + SET_SYSTEM_SLEEP_PM_OPS(tegra_wdt_runtime_suspend, + tegra_wdt_runtime_resume) +}; + +static struct platform_driver tegra_wdt_driver = { + .probe = tegra_wdt_probe, + .remove = tegra_wdt_remove, + .driver = { + .owner = THIS_MODULE, + .name = "tegra-wdt", + .pm = &tegra_wdt_pm_ops, + .of_match_table = tegra_wdt_of_match, + }, +}; +module_platform_driver(tegra_wdt_driver); + +MODULE_AUTHOR("NVIDIA Corporation"); +MODULE_DESCRIPTION("Tegra Watchdog Driver"); +MODULE_LICENSE("GPL v2"); |