diff options
Diffstat (limited to 'drivers/watchdog/omap_wdt.c')
-rw-r--r-- | drivers/watchdog/omap_wdt.c | 374 |
1 files changed, 374 insertions, 0 deletions
diff --git a/drivers/watchdog/omap_wdt.c b/drivers/watchdog/omap_wdt.c new file mode 100644 index 0000000000..a7a12f2fe9 --- /dev/null +++ b/drivers/watchdog/omap_wdt.c @@ -0,0 +1,374 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * omap_wdt.c + * + * Watchdog driver for the TI OMAP 16xx & 24xx/34xx 32KHz (non-secure) watchdog + * + * Author: MontaVista Software, Inc. + * <gdavis@mvista.com> or <source@mvista.com> + * + * 2003 (c) MontaVista Software, Inc. + * + * History: + * + * 20030527: George G. Davis <gdavis@mvista.com> + * Initially based on linux-2.4.19-rmk7-pxa1/drivers/char/sa1100_wdt.c + * (c) Copyright 2000 Oleg Drokin <green@crimea.edu> + * Based on SoftDog driver by Alan Cox <alan@lxorguk.ukuu.org.uk> + * + * Copyright (c) 2004 Texas Instruments. + * 1. Modified to support OMAP1610 32-KHz watchdog timer + * 2. Ported to 2.6 kernel + * + * Copyright (c) 2005 David Brownell + * Use the driver model and standard identifiers; handle bigger timeouts. + */ + +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +#include <linux/module.h> +#include <linux/mod_devicetable.h> +#include <linux/types.h> +#include <linux/kernel.h> +#include <linux/mm.h> +#include <linux/watchdog.h> +#include <linux/reboot.h> +#include <linux/err.h> +#include <linux/platform_device.h> +#include <linux/moduleparam.h> +#include <linux/io.h> +#include <linux/slab.h> +#include <linux/pm_runtime.h> +#include <linux/platform_data/omap-wd-timer.h> + +#include "omap_wdt.h" + +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 unsigned timer_margin; +module_param(timer_margin, uint, 0); +MODULE_PARM_DESC(timer_margin, "initial watchdog timeout (in seconds)"); + +#define to_omap_wdt_dev(_wdog) container_of(_wdog, struct omap_wdt_dev, wdog) + +static bool early_enable; +module_param(early_enable, bool, 0); +MODULE_PARM_DESC(early_enable, + "Watchdog is started on module insertion (default=0)"); + +struct omap_wdt_dev { + struct watchdog_device wdog; + void __iomem *base; /* physical */ + struct device *dev; + bool omap_wdt_users; + int wdt_trgr_pattern; + struct mutex lock; /* to avoid races with PM */ +}; + +static void omap_wdt_reload(struct omap_wdt_dev *wdev) +{ + void __iomem *base = wdev->base; + + /* wait for posted write to complete */ + while ((readl_relaxed(base + OMAP_WATCHDOG_WPS)) & 0x08) + cpu_relax(); + + wdev->wdt_trgr_pattern = ~wdev->wdt_trgr_pattern; + writel_relaxed(wdev->wdt_trgr_pattern, (base + OMAP_WATCHDOG_TGR)); + + /* wait for posted write to complete */ + while ((readl_relaxed(base + OMAP_WATCHDOG_WPS)) & 0x08) + cpu_relax(); + /* reloaded WCRR from WLDR */ +} + +static void omap_wdt_enable(struct omap_wdt_dev *wdev) +{ + void __iomem *base = wdev->base; + + /* Sequence to enable the watchdog */ + writel_relaxed(0xBBBB, base + OMAP_WATCHDOG_SPR); + while ((readl_relaxed(base + OMAP_WATCHDOG_WPS)) & 0x10) + cpu_relax(); + + writel_relaxed(0x4444, base + OMAP_WATCHDOG_SPR); + while ((readl_relaxed(base + OMAP_WATCHDOG_WPS)) & 0x10) + cpu_relax(); +} + +static void omap_wdt_disable(struct omap_wdt_dev *wdev) +{ + void __iomem *base = wdev->base; + + /* sequence required to disable watchdog */ + writel_relaxed(0xAAAA, base + OMAP_WATCHDOG_SPR); /* TIMER_MODE */ + while (readl_relaxed(base + OMAP_WATCHDOG_WPS) & 0x10) + cpu_relax(); + + writel_relaxed(0x5555, base + OMAP_WATCHDOG_SPR); /* TIMER_MODE */ + while (readl_relaxed(base + OMAP_WATCHDOG_WPS) & 0x10) + cpu_relax(); +} + +static void omap_wdt_set_timer(struct omap_wdt_dev *wdev, + unsigned int timeout) +{ + u32 pre_margin = GET_WLDR_VAL(timeout); + void __iomem *base = wdev->base; + + /* just count up at 32 KHz */ + while (readl_relaxed(base + OMAP_WATCHDOG_WPS) & 0x04) + cpu_relax(); + + writel_relaxed(pre_margin, base + OMAP_WATCHDOG_LDR); + while (readl_relaxed(base + OMAP_WATCHDOG_WPS) & 0x04) + cpu_relax(); +} + +static int omap_wdt_start(struct watchdog_device *wdog) +{ + struct omap_wdt_dev *wdev = to_omap_wdt_dev(wdog); + void __iomem *base = wdev->base; + + mutex_lock(&wdev->lock); + + wdev->omap_wdt_users = true; + + pm_runtime_get_sync(wdev->dev); + + /* + * Make sure the watchdog is disabled. This is unfortunately required + * because writing to various registers with the watchdog running has no + * effect. + */ + omap_wdt_disable(wdev); + + /* initialize prescaler */ + while (readl_relaxed(base + OMAP_WATCHDOG_WPS) & 0x01) + cpu_relax(); + + writel_relaxed((1 << 5) | (PTV << 2), base + OMAP_WATCHDOG_CNTRL); + while (readl_relaxed(base + OMAP_WATCHDOG_WPS) & 0x01) + cpu_relax(); + + omap_wdt_set_timer(wdev, wdog->timeout); + omap_wdt_reload(wdev); /* trigger loading of new timeout value */ + omap_wdt_enable(wdev); + + mutex_unlock(&wdev->lock); + + return 0; +} + +static int omap_wdt_stop(struct watchdog_device *wdog) +{ + struct omap_wdt_dev *wdev = to_omap_wdt_dev(wdog); + + mutex_lock(&wdev->lock); + omap_wdt_disable(wdev); + pm_runtime_put_sync(wdev->dev); + wdev->omap_wdt_users = false; + mutex_unlock(&wdev->lock); + return 0; +} + +static int omap_wdt_ping(struct watchdog_device *wdog) +{ + struct omap_wdt_dev *wdev = to_omap_wdt_dev(wdog); + + mutex_lock(&wdev->lock); + omap_wdt_reload(wdev); + mutex_unlock(&wdev->lock); + + return 0; +} + +static int omap_wdt_set_timeout(struct watchdog_device *wdog, + unsigned int timeout) +{ + struct omap_wdt_dev *wdev = to_omap_wdt_dev(wdog); + + mutex_lock(&wdev->lock); + omap_wdt_disable(wdev); + omap_wdt_set_timer(wdev, timeout); + omap_wdt_enable(wdev); + omap_wdt_reload(wdev); + wdog->timeout = timeout; + mutex_unlock(&wdev->lock); + + return 0; +} + +static unsigned int omap_wdt_get_timeleft(struct watchdog_device *wdog) +{ + struct omap_wdt_dev *wdev = to_omap_wdt_dev(wdog); + void __iomem *base = wdev->base; + u32 value; + + value = readl_relaxed(base + OMAP_WATCHDOG_CRR); + return GET_WCCR_SECS(value); +} + +static const struct watchdog_info omap_wdt_info = { + .options = WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING, + .identity = "OMAP Watchdog", +}; + +static const struct watchdog_ops omap_wdt_ops = { + .owner = THIS_MODULE, + .start = omap_wdt_start, + .stop = omap_wdt_stop, + .ping = omap_wdt_ping, + .set_timeout = omap_wdt_set_timeout, + .get_timeleft = omap_wdt_get_timeleft, +}; + +static int omap_wdt_probe(struct platform_device *pdev) +{ + struct omap_wd_timer_platform_data *pdata = dev_get_platdata(&pdev->dev); + struct omap_wdt_dev *wdev; + int ret; + + wdev = devm_kzalloc(&pdev->dev, sizeof(*wdev), GFP_KERNEL); + if (!wdev) + return -ENOMEM; + + wdev->omap_wdt_users = false; + wdev->dev = &pdev->dev; + wdev->wdt_trgr_pattern = 0x1234; + mutex_init(&wdev->lock); + + /* reserve static register mappings */ + wdev->base = devm_platform_ioremap_resource(pdev, 0); + if (IS_ERR(wdev->base)) + return PTR_ERR(wdev->base); + + wdev->wdog.info = &omap_wdt_info; + wdev->wdog.ops = &omap_wdt_ops; + wdev->wdog.min_timeout = TIMER_MARGIN_MIN; + wdev->wdog.max_timeout = TIMER_MARGIN_MAX; + wdev->wdog.timeout = TIMER_MARGIN_DEFAULT; + wdev->wdog.parent = &pdev->dev; + + watchdog_init_timeout(&wdev->wdog, timer_margin, &pdev->dev); + + watchdog_set_nowayout(&wdev->wdog, nowayout); + + platform_set_drvdata(pdev, wdev); + + pm_runtime_enable(wdev->dev); + pm_runtime_get_sync(wdev->dev); + + if (pdata && pdata->read_reset_sources) { + u32 rs = pdata->read_reset_sources(); + if (rs & (1 << OMAP_MPU_WD_RST_SRC_ID_SHIFT)) + wdev->wdog.bootstatus = WDIOF_CARDRESET; + } + + if (early_enable) { + omap_wdt_start(&wdev->wdog); + set_bit(WDOG_HW_RUNNING, &wdev->wdog.status); + } else { + omap_wdt_disable(wdev); + } + + ret = watchdog_register_device(&wdev->wdog); + if (ret) { + pm_runtime_put(wdev->dev); + pm_runtime_disable(wdev->dev); + return ret; + } + + pr_info("OMAP Watchdog Timer Rev 0x%02x: initial timeout %d sec\n", + readl_relaxed(wdev->base + OMAP_WATCHDOG_REV) & 0xFF, + wdev->wdog.timeout); + + if (early_enable) + omap_wdt_start(&wdev->wdog); + + pm_runtime_put(wdev->dev); + + return 0; +} + +static void omap_wdt_shutdown(struct platform_device *pdev) +{ + struct omap_wdt_dev *wdev = platform_get_drvdata(pdev); + + mutex_lock(&wdev->lock); + if (wdev->omap_wdt_users) { + omap_wdt_disable(wdev); + pm_runtime_put_sync(wdev->dev); + } + mutex_unlock(&wdev->lock); +} + +static void omap_wdt_remove(struct platform_device *pdev) +{ + struct omap_wdt_dev *wdev = platform_get_drvdata(pdev); + + pm_runtime_disable(wdev->dev); + watchdog_unregister_device(&wdev->wdog); +} + +/* REVISIT ... not clear this is the best way to handle system suspend; and + * it's very inappropriate for selective device suspend (e.g. suspending this + * through sysfs rather than by stopping the watchdog daemon). Also, this + * may not play well enough with NOWAYOUT... + */ + +static int omap_wdt_suspend(struct platform_device *pdev, pm_message_t state) +{ + struct omap_wdt_dev *wdev = platform_get_drvdata(pdev); + + mutex_lock(&wdev->lock); + if (wdev->omap_wdt_users) { + omap_wdt_disable(wdev); + pm_runtime_put_sync(wdev->dev); + } + mutex_unlock(&wdev->lock); + + return 0; +} + +static int omap_wdt_resume(struct platform_device *pdev) +{ + struct omap_wdt_dev *wdev = platform_get_drvdata(pdev); + + mutex_lock(&wdev->lock); + if (wdev->omap_wdt_users) { + pm_runtime_get_sync(wdev->dev); + omap_wdt_enable(wdev); + omap_wdt_reload(wdev); + } + mutex_unlock(&wdev->lock); + + return 0; +} + +static const struct of_device_id omap_wdt_of_match[] = { + { .compatible = "ti,omap3-wdt", }, + {}, +}; +MODULE_DEVICE_TABLE(of, omap_wdt_of_match); + +static struct platform_driver omap_wdt_driver = { + .probe = omap_wdt_probe, + .remove_new = omap_wdt_remove, + .shutdown = omap_wdt_shutdown, + .suspend = pm_ptr(omap_wdt_suspend), + .resume = pm_ptr(omap_wdt_resume), + .driver = { + .name = "omap_wdt", + .of_match_table = omap_wdt_of_match, + }, +}; + +module_platform_driver(omap_wdt_driver); + +MODULE_AUTHOR("George G. Davis"); +MODULE_LICENSE("GPL"); +MODULE_ALIAS("platform:omap_wdt"); |