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/*
* Watchdog driver for CSR Atlas7
*
* Copyright (c) 2015 Cambridge Silicon Radio Limited, a CSR plc group company.
*
* Licensed under GPLv2.
*/
#include <linux/clk.h>
#include <linux/io.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/watchdog.h>
#define ATLAS7_TIMER_WDT_INDEX 5
#define ATLAS7_WDT_DEFAULT_TIMEOUT 20
#define ATLAS7_WDT_CNT_CTRL (0 + 4 * ATLAS7_TIMER_WDT_INDEX)
#define ATLAS7_WDT_CNT_MATCH (0x18 + 4 * ATLAS7_TIMER_WDT_INDEX)
#define ATLAS7_WDT_CNT (0x48 + 4 * ATLAS7_TIMER_WDT_INDEX)
#define ATLAS7_WDT_CNT_EN (BIT(0) | BIT(1))
#define ATLAS7_WDT_EN 0x64
static unsigned int timeout = ATLAS7_WDT_DEFAULT_TIMEOUT;
static bool nowayout = WATCHDOG_NOWAYOUT;
module_param(timeout, uint, 0);
module_param(nowayout, bool, 0);
MODULE_PARM_DESC(timeout, "Default watchdog timeout (in seconds)");
MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
struct atlas7_wdog {
struct device *dev;
void __iomem *base;
unsigned long tick_rate;
struct clk *clk;
};
static unsigned int atlas7_wdt_gettimeleft(struct watchdog_device *wdd)
{
struct atlas7_wdog *wdt = watchdog_get_drvdata(wdd);
u32 counter, match, delta;
counter = readl(wdt->base + ATLAS7_WDT_CNT);
match = readl(wdt->base + ATLAS7_WDT_CNT_MATCH);
delta = match - counter;
return delta / wdt->tick_rate;
}
static int atlas7_wdt_ping(struct watchdog_device *wdd)
{
struct atlas7_wdog *wdt = watchdog_get_drvdata(wdd);
u32 counter, match, delta;
counter = readl(wdt->base + ATLAS7_WDT_CNT);
delta = wdd->timeout * wdt->tick_rate;
match = counter + delta;
writel(match, wdt->base + ATLAS7_WDT_CNT_MATCH);
return 0;
}
static int atlas7_wdt_enable(struct watchdog_device *wdd)
{
struct atlas7_wdog *wdt = watchdog_get_drvdata(wdd);
atlas7_wdt_ping(wdd);
writel(readl(wdt->base + ATLAS7_WDT_CNT_CTRL) | ATLAS7_WDT_CNT_EN,
wdt->base + ATLAS7_WDT_CNT_CTRL);
writel(1, wdt->base + ATLAS7_WDT_EN);
return 0;
}
static int atlas7_wdt_disable(struct watchdog_device *wdd)
{
struct atlas7_wdog *wdt = watchdog_get_drvdata(wdd);
writel(0, wdt->base + ATLAS7_WDT_EN);
writel(readl(wdt->base + ATLAS7_WDT_CNT_CTRL) & ~ATLAS7_WDT_CNT_EN,
wdt->base + ATLAS7_WDT_CNT_CTRL);
return 0;
}
static int atlas7_wdt_settimeout(struct watchdog_device *wdd, unsigned int to)
{
wdd->timeout = to;
return 0;
}
#define OPTIONS (WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE)
static const struct watchdog_info atlas7_wdt_ident = {
.options = OPTIONS,
.firmware_version = 0,
.identity = "atlas7 Watchdog",
};
static const struct watchdog_ops atlas7_wdt_ops = {
.owner = THIS_MODULE,
.start = atlas7_wdt_enable,
.stop = atlas7_wdt_disable,
.get_timeleft = atlas7_wdt_gettimeleft,
.ping = atlas7_wdt_ping,
.set_timeout = atlas7_wdt_settimeout,
};
static struct watchdog_device atlas7_wdd = {
.info = &atlas7_wdt_ident,
.ops = &atlas7_wdt_ops,
.timeout = ATLAS7_WDT_DEFAULT_TIMEOUT,
};
static const struct of_device_id atlas7_wdt_ids[] = {
{ .compatible = "sirf,atlas7-tick"},
{}
};
static void atlas7_clk_disable_unprepare(void *data)
{
clk_disable_unprepare(data);
}
static int atlas7_wdt_probe(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
struct atlas7_wdog *wdt;
struct clk *clk;
int ret;
wdt = devm_kzalloc(dev, sizeof(*wdt), GFP_KERNEL);
if (!wdt)
return -ENOMEM;
wdt->base = devm_platform_ioremap_resource(pdev, 0);
if (IS_ERR(wdt->base))
return PTR_ERR(wdt->base);
clk = devm_clk_get(dev, NULL);
if (IS_ERR(clk))
return PTR_ERR(clk);
ret = clk_prepare_enable(clk);
if (ret) {
dev_err(dev, "clk enable failed\n");
return ret;
}
ret = devm_add_action_or_reset(dev, atlas7_clk_disable_unprepare, clk);
if (ret)
return ret;
/* disable watchdog hardware */
writel(0, wdt->base + ATLAS7_WDT_CNT_CTRL);
wdt->tick_rate = clk_get_rate(clk);
if (!wdt->tick_rate)
return -EINVAL;
wdt->clk = clk;
atlas7_wdd.min_timeout = 1;
atlas7_wdd.max_timeout = UINT_MAX / wdt->tick_rate;
watchdog_init_timeout(&atlas7_wdd, 0, dev);
watchdog_set_nowayout(&atlas7_wdd, nowayout);
watchdog_set_drvdata(&atlas7_wdd, wdt);
platform_set_drvdata(pdev, &atlas7_wdd);
watchdog_stop_on_reboot(&atlas7_wdd);
watchdog_stop_on_unregister(&atlas7_wdd);
return devm_watchdog_register_device(dev, &atlas7_wdd);
}
static int __maybe_unused atlas7_wdt_suspend(struct device *dev)
{
/*
* NOTE:timer controller registers settings are saved
* and restored back by the timer-atlas7.c
*/
return 0;
}
static int __maybe_unused atlas7_wdt_resume(struct device *dev)
{
struct watchdog_device *wdd = dev_get_drvdata(dev);
/*
* NOTE: Since timer controller registers settings are saved
* and restored back by the timer-atlas7.c, so we need not
* update WD settings except refreshing timeout.
*/
atlas7_wdt_ping(wdd);
return 0;
}
static SIMPLE_DEV_PM_OPS(atlas7_wdt_pm_ops,
atlas7_wdt_suspend, atlas7_wdt_resume);
MODULE_DEVICE_TABLE(of, atlas7_wdt_ids);
static struct platform_driver atlas7_wdt_driver = {
.driver = {
.name = "atlas7-wdt",
.pm = &atlas7_wdt_pm_ops,
.of_match_table = atlas7_wdt_ids,
},
.probe = atlas7_wdt_probe,
};
module_platform_driver(atlas7_wdt_driver);
MODULE_DESCRIPTION("CSRatlas7 watchdog driver");
MODULE_AUTHOR("Guo Zeng <Guo.Zeng@csr.com>");
MODULE_LICENSE("GPL v2");
MODULE_ALIAS("platform:atlas7-wdt");
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