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// SPDX-License-Identifier: GPL-2.0
/*
* 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
*/
#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 <linux/delay.h>
#include <linux/reboot.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;
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 int pnx4008_restart_handler(struct watchdog_device *wdd,
unsigned long mode, void *cmd)
{
const char *boot_cmd = cmd;
/*
* Verify if a "cmd" passed from the userspace program rebooting
* the system; if available, handle it.
* - For details, see the 'reboot' syscall in kernel/reboot.c
* - If the received "cmd" is not supported, use the default mode.
*/
if (boot_cmd) {
if (boot_cmd[0] == 'h')
mode = REBOOT_HARD;
else if (boot_cmd[0] == 's')
mode = REBOOT_SOFT;
}
if (mode == REBOOT_SOFT) {
/* Force match output active */
writel(EXT_MATCH0, WDTIM_EMR(wdt_base));
/* Internal reset on match output (RESOUT_N not asserted) */
writel(M_RES1, WDTIM_MCTRL(wdt_base));
} else {
/* Instant assert of RESETOUT_N with pulse length 1mS */
writel(13000, WDTIM_PULSE(wdt_base));
writel(M_RES2 | RESFRC1 | RESFRC2, WDTIM_MCTRL(wdt_base));
}
/* Wait for watchdog to reset system */
mdelay(1000);
return NOTIFY_DONE;
}
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,
.restart = pnx4008_restart_handler,
};
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 device *dev = &pdev->dev;
int ret = 0;
watchdog_init_timeout(&pnx4008_wdd, heartbeat, dev);
wdt_base = devm_platform_ioremap_resource(pdev, 0);
if (IS_ERR(wdt_base))
return PTR_ERR(wdt_base);
wdt_clk = devm_clk_get_enabled(dev, NULL);
if (IS_ERR(wdt_clk))
return PTR_ERR(wdt_clk);
pnx4008_wdd.bootstatus = (readl(WDTIM_RES(wdt_base)) & WDOG_RESET) ?
WDIOF_CARDRESET : 0;
pnx4008_wdd.parent = dev;
watchdog_set_nowayout(&pnx4008_wdd, nowayout);
watchdog_set_restart_priority(&pnx4008_wdd, 128);
if (readl(WDTIM_CTRL(wdt_base)) & COUNT_ENAB)
set_bit(WDOG_HW_RUNNING, &pnx4008_wdd.status);
ret = devm_watchdog_register_device(dev, &pnx4008_wdd);
if (ret < 0)
return ret;
dev_info(dev, "heartbeat %d sec\n", pnx4008_wdd.timeout);
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,
};
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");
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