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