- 根目录:
- drivers
- watchdog
- pnx4008_wdt.c
/*
* drivers/char/watchdog/pnx4008_wdt.c
*
* Watchdog driver for PNX4008 board
*
* Authors: Dmitry Chigirev <source@mvista.com>,
* Vitaly Wool <vitalywool@gmail.com>
* Based on sa1100 driver,
* Copyright (C) 2000 Oleg Drokin <green@crimea.edu>
*
* 2005-2006 (c) MontaVista Software, Inc.
*
* (C) 2012 Wolfram Sang, Pengutronix
*
* This file is licensed under the terms of the GNU General Public License
* version 2. This program is licensed "as is" without any warranty of any
* kind, whether express or implied.
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/watchdog.h>
#include <linux/platform_device.h>
#include <linux/clk.h>
#include <linux/spinlock.h>
#include <linux/io.h>
#include <linux/slab.h>
#include <linux/err.h>
#include <linux/of.h>
#include <mach/hardware.h>
/* WatchDog Timer - Chapter 23 Page 207 */
#define DEFAULT_HEARTBEAT 19
#define MAX_HEARTBEAT 60
/* Watchdog timer register set definition */
#define WDTIM_INT(p) ((p) + 0x0)
#define WDTIM_CTRL(p) ((p) + 0x4)
#define WDTIM_COUNTER(p) ((p) + 0x8)
#define WDTIM_MCTRL(p) ((p) + 0xC)
#define WDTIM_MATCH0(p) ((p) + 0x10)
#define WDTIM_EMR(p) ((p) + 0x14)
#define WDTIM_PULSE(p) ((p) + 0x18)
#define WDTIM_RES(p) ((p) + 0x1C)
/* WDTIM_INT bit definitions */
#define MATCH_INT 1
/* WDTIM_CTRL bit definitions */
#define COUNT_ENAB 1
#define RESET_COUNT (1 << 1)
#define DEBUG_EN (1 << 2)
/* WDTIM_MCTRL bit definitions */
#define MR0_INT 1
#undef RESET_COUNT0
#define RESET_COUNT0 (1 << 2)
#define STOP_COUNT0 (1 << 2)
#define M_RES1 (1 << 3)
#define M_RES2 (1 << 4)
#define RESFRC1 (1 << 5)
#define RESFRC2 (1 << 6)
/* WDTIM_EMR bit definitions */
#define EXT_MATCH0 1
#define MATCH_OUTPUT_HIGH (2 << 4) /*a MATCH_CTRL setting */
/* WDTIM_RES bit definitions */
#define WDOG_RESET 1 /* read only */
#define WDOG_COUNTER_RATE 13000000 /*the counter clock is 13 MHz fixed */
static bool nowayout = WATCHDOG_NOWAYOUT;
static unsigned int heartbeat = DEFAULT_HEARTBEAT;
static DEFINE_SPINLOCK(io_lock);
static void __iomem *wdt_base;
static struct clk *wdt_clk;
static int pnx4008_wdt_start(struct watchdog_device *wdd)
{
spin_lock(&io_lock);
/* stop counter, initiate counter reset */
writel(RESET_COUNT, WDTIM_CTRL(wdt_base));
/*wait for reset to complete. 100% guarantee event */
while (readl(WDTIM_COUNTER(wdt_base)))
cpu_relax();
/* internal and external reset, stop after that */
writel(M_RES2 | STOP_COUNT0 | RESET_COUNT0, WDTIM_MCTRL(wdt_base));
/* configure match output */
writel(MATCH_OUTPUT_HIGH, WDTIM_EMR(wdt_base));
/* clear interrupt, just in case */
writel(MATCH_INT, WDTIM_INT(wdt_base));
/* the longest pulse period 65541/(13*10^6) seconds ~ 5 ms. */
writel(0xFFFF, WDTIM_PULSE(wdt_base));
writel(wdd->timeout * WDOG_COUNTER_RATE, WDTIM_MATCH0(wdt_base));
/*enable counter, stop when debugger active */
writel(COUNT_ENAB | DEBUG_EN, WDTIM_CTRL(wdt_base));
spin_unlock(&io_lock);
return 0;
}
static int pnx4008_wdt_stop(struct watchdog_device *wdd)
{
spin_lock(&io_lock);
writel(0, WDTIM_CTRL(wdt_base)); /*stop counter */
spin_unlock(&io_lock);
return 0;
}
static int pnx4008_wdt_set_timeout(struct watchdog_device *wdd,
unsigned int new_timeout)
{
wdd->timeout = new_timeout;
return 0;
}
static const struct watchdog_info pnx4008_wdt_ident = {
.options = WDIOF_CARDRESET | WDIOF_MAGICCLOSE |
WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
.identity = "PNX4008 Watchdog",
};
static const struct watchdog_ops pnx4008_wdt_ops = {
.owner = THIS_MODULE,
.start = pnx4008_wdt_start,
.stop = pnx4008_wdt_stop,
.set_timeout = pnx4008_wdt_set_timeout,
};
static struct watchdog_device pnx4008_wdd = {
.info = &pnx4008_wdt_ident,
.ops = &pnx4008_wdt_ops,
.timeout = DEFAULT_HEARTBEAT,
.min_timeout = 1,
.max_timeout = MAX_HEARTBEAT,
};
static int pnx4008_wdt_probe(struct platform_device *pdev)
{
struct resource *r;
int ret = 0;
watchdog_init_timeout(&pnx4008_wdd, heartbeat, &pdev->dev);
r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
wdt_base = devm_ioremap_resource(&pdev->dev, r);
if (IS_ERR(wdt_base))
return PTR_ERR(wdt_base);
wdt_clk = devm_clk_get(&pdev->dev, NULL);
if (IS_ERR(wdt_clk))
return PTR_ERR(wdt_clk);
ret = clk_prepare_enable(wdt_clk);
if (ret)
return ret;
pnx4008_wdd.bootstatus = (readl(WDTIM_RES(wdt_base)) & WDOG_RESET) ?
WDIOF_CARDRESET : 0;
pnx4008_wdd.parent = &pdev->dev;
watchdog_set_nowayout(&pnx4008_wdd, nowayout);
pnx4008_wdt_stop(&pnx4008_wdd); /* disable for now */
ret = watchdog_register_device(&pnx4008_wdd);
if (ret < 0) {
dev_err(&pdev->dev, "cannot register watchdog device\n");
goto disable_clk;
}
dev_info(&pdev->dev, "PNX4008 Watchdog Timer: heartbeat %d sec\n",
pnx4008_wdd.timeout);
return 0;
disable_clk:
clk_disable_unprepare(wdt_clk);
return ret;
}
static int pnx4008_wdt_remove(struct platform_device *pdev)
{
watchdog_unregister_device(&pnx4008_wdd);
clk_disable_unprepare(wdt_clk);
return 0;
}
#ifdef CONFIG_OF
static const struct of_device_id pnx4008_wdt_match[] = {
{ .compatible = "nxp,pnx4008-wdt" },
{ }
};
MODULE_DEVICE_TABLE(of, pnx4008_wdt_match);
#endif
static struct platform_driver platform_wdt_driver = {
.driver = {
.name = "pnx4008-watchdog",
.of_match_table = of_match_ptr(pnx4008_wdt_match),
},
.probe = pnx4008_wdt_probe,
.remove = pnx4008_wdt_remove,
};
module_platform_driver(platform_wdt_driver);
MODULE_AUTHOR("MontaVista Software, Inc. <source@mvista.com>");
MODULE_AUTHOR("Wolfram Sang <kernel@pengutronix.de>");
MODULE_DESCRIPTION("PNX4008 Watchdog Driver");
module_param(heartbeat, uint, 0);
MODULE_PARM_DESC(heartbeat,
"Watchdog heartbeat period in seconds from 1 to "
__MODULE_STRING(MAX_HEARTBEAT) ", default "
__MODULE_STRING(DEFAULT_HEARTBEAT));
module_param(nowayout, bool, 0);
MODULE_PARM_DESC(nowayout,
"Set to 1 to keep watchdog running after device release");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:pnx4008-watchdog");