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/*
* Meson Watchdog Driver
*
* Copyright (c) 2014 Carlo Caione
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*/
#include <linux/clk.h>
#include <linux/delay.h>
#include <linux/err.h>
#include <linux/init.h>
#include <linux/io.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/of.h>
#include <linux/of_device.h>
#include <linux/platform_device.h>
#include <linux/types.h>
#include <linux/watchdog.h>
#define DRV_NAME "meson_wdt"
#define MESON_WDT_TC 0x00
#define MESON_WDT_DC_RESET (3 << 24)
#define MESON_WDT_RESET 0x04
#define MESON_WDT_TIMEOUT 30
#define MESON_WDT_MIN_TIMEOUT 1
#define MESON_SEC_TO_TC(s, c) ((s) * (c))
static bool nowayout = WATCHDOG_NOWAYOUT;
static unsigned int timeout = MESON_WDT_TIMEOUT;
struct meson_wdt_data {
unsigned int enable;
unsigned int terminal_count_mask;
unsigned int count_unit;
};
static struct meson_wdt_data meson6_wdt_data = {
.enable = BIT(22),
.terminal_count_mask = 0x3fffff,
.count_unit = 100000, /* 10 us */
};
static struct meson_wdt_data meson8b_wdt_data = {
.enable = BIT(19),
.terminal_count_mask = 0xffff,
.count_unit = 7812, /* 128 us */
};
struct meson_wdt_dev {
struct watchdog_device wdt_dev;
void __iomem *wdt_base;
const struct meson_wdt_data *data;
};
static int meson_wdt_restart(struct watchdog_device *wdt_dev)
{
struct meson_wdt_dev *meson_wdt = watchdog_get_drvdata(wdt_dev);
u32 tc_reboot = MESON_WDT_DC_RESET;
tc_reboot |= meson_wdt->data->enable;
while (1) {
writel(tc_reboot, meson_wdt->wdt_base + MESON_WDT_TC);
mdelay(5);
}
return 0;
}
static int meson_wdt_ping(struct watchdog_device *wdt_dev)
{
struct meson_wdt_dev *meson_wdt = watchdog_get_drvdata(wdt_dev);
writel(0, meson_wdt->wdt_base + MESON_WDT_RESET);
return 0;
}
static void meson_wdt_change_timeout(struct watchdog_device *wdt_dev,
unsigned int timeout)
{
struct meson_wdt_dev *meson_wdt = watchdog_get_drvdata(wdt_dev);
u32 reg;
reg = readl(meson_wdt->wdt_base + MESON_WDT_TC);
reg &= ~meson_wdt->data->terminal_count_mask;
reg |= MESON_SEC_TO_TC(timeout, meson_wdt->data->count_unit);
writel(reg, meson_wdt->wdt_base + MESON_WDT_TC);
}
static int meson_wdt_set_timeout(struct watchdog_device *wdt_dev,
unsigned int timeout)
{
wdt_dev->timeout = timeout;
meson_wdt_change_timeout(wdt_dev, timeout);
meson_wdt_ping(wdt_dev);
return 0;
}
static int meson_wdt_stop(struct watchdog_device *wdt_dev)
{
struct meson_wdt_dev *meson_wdt = watchdog_get_drvdata(wdt_dev);
u32 reg;
reg = readl(meson_wdt->wdt_base + MESON_WDT_TC);
reg &= ~meson_wdt->data->enable;
writel(reg, meson_wdt->wdt_base + MESON_WDT_TC);
return 0;
}
static int meson_wdt_start(struct watchdog_device *wdt_dev)
{
struct meson_wdt_dev *meson_wdt = watchdog_get_drvdata(wdt_dev);
u32 reg;
meson_wdt_change_timeout(wdt_dev, meson_wdt->wdt_dev.timeout);
meson_wdt_ping(wdt_dev);
reg = readl(meson_wdt->wdt_base + MESON_WDT_TC);
reg |= meson_wdt->data->enable;
writel(reg, meson_wdt->wdt_base + MESON_WDT_TC);
return 0;
}
static const struct watchdog_info meson_wdt_info = {
.identity = DRV_NAME,
.options = WDIOF_SETTIMEOUT |
WDIOF_KEEPALIVEPING |
WDIOF_MAGICCLOSE,
};
static const struct watchdog_ops meson_wdt_ops = {
.owner = THIS_MODULE,
.start = meson_wdt_start,
.stop = meson_wdt_stop,
.ping = meson_wdt_ping,
.set_timeout = meson_wdt_set_timeout,
.restart = meson_wdt_restart,
};
static const struct of_device_id meson_wdt_dt_ids[] = {
{ .compatible = "amlogic,meson6-wdt", .data = &meson6_wdt_data },
{ .compatible = "amlogic,meson8b-wdt", .data = &meson8b_wdt_data },
{ /* sentinel */ }
};
MODULE_DEVICE_TABLE(of, meson_wdt_dt_ids);
static int meson_wdt_probe(struct platform_device *pdev)
{
struct resource *res;
struct meson_wdt_dev *meson_wdt;
const struct of_device_id *of_id;
int err;
meson_wdt = devm_kzalloc(&pdev->dev, sizeof(*meson_wdt), GFP_KERNEL);
if (!meson_wdt)
return -ENOMEM;
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
meson_wdt->wdt_base = devm_ioremap_resource(&pdev->dev, res);
if (IS_ERR(meson_wdt->wdt_base))
return PTR_ERR(meson_wdt->wdt_base);
of_id = of_match_device(meson_wdt_dt_ids, &pdev->dev);
if (!of_id) {
dev_err(&pdev->dev, "Unable to initialize WDT data\n");
return -ENODEV;
}
meson_wdt->data = of_id->data;
meson_wdt->wdt_dev.parent = &pdev->dev;
meson_wdt->wdt_dev.info = &meson_wdt_info;
meson_wdt->wdt_dev.ops = &meson_wdt_ops;
meson_wdt->wdt_dev.max_timeout =
meson_wdt->data->terminal_count_mask / meson_wdt->data->count_unit;
meson_wdt->wdt_dev.min_timeout = MESON_WDT_MIN_TIMEOUT;
meson_wdt->wdt_dev.timeout = min_t(unsigned int,
MESON_WDT_TIMEOUT,
meson_wdt->wdt_dev.max_timeout);
watchdog_set_drvdata(&meson_wdt->wdt_dev, meson_wdt);
watchdog_init_timeout(&meson_wdt->wdt_dev, timeout, &pdev->dev);
watchdog_set_nowayout(&meson_wdt->wdt_dev, nowayout);
watchdog_set_restart_priority(&meson_wdt->wdt_dev, 128);
meson_wdt_stop(&meson_wdt->wdt_dev);
err = watchdog_register_device(&meson_wdt->wdt_dev);
if (err)
return err;
platform_set_drvdata(pdev, meson_wdt);
dev_info(&pdev->dev, "Watchdog enabled (timeout=%d sec, nowayout=%d)",
meson_wdt->wdt_dev.timeout, nowayout);
return 0;
}
static int meson_wdt_remove(struct platform_device *pdev)
{
struct meson_wdt_dev *meson_wdt = platform_get_drvdata(pdev);
watchdog_unregister_device(&meson_wdt->wdt_dev);
return 0;
}
static void meson_wdt_shutdown(struct platform_device *pdev)
{
struct meson_wdt_dev *meson_wdt = platform_get_drvdata(pdev);
meson_wdt_stop(&meson_wdt->wdt_dev);
}
static struct platform_driver meson_wdt_driver = {
.probe = meson_wdt_probe,
.remove = meson_wdt_remove,
.shutdown = meson_wdt_shutdown,
.driver = {
.name = DRV_NAME,
.of_match_table = meson_wdt_dt_ids,
},
};
module_platform_driver(meson_wdt_driver);
module_param(timeout, uint, 0);
MODULE_PARM_DESC(timeout, "Watchdog heartbeat in seconds");
module_param(nowayout, bool, 0);
MODULE_PARM_DESC(nowayout,
"Watchdog cannot be stopped once started (default="
__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Carlo Caione <carlo@caione.org>");
MODULE_DESCRIPTION("Meson Watchdog Timer Driver");
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