linux/drivers/watchdog/imx7ulp_wdt.c

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// SPDX-License-Identifier: GPL-2.0
/*
* Copyright 2019 NXP.
*/
#include <linux/clk.h>
#include <linux/io.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/reboot.h>
#include <linux/watchdog.h>
#define WDOG_CS 0x0
#define WDOG_CS_CMD32EN BIT(13)
#define WDOG_CS_ULK BIT(11)
#define WDOG_CS_RCS BIT(10)
#define LPO_CLK 0x1
#define LPO_CLK_SHIFT 8
#define WDOG_CS_CLK (LPO_CLK << LPO_CLK_SHIFT)
#define WDOG_CS_EN BIT(7)
#define WDOG_CS_UPDATE BIT(5)
#define WDOG_CNT 0x4
#define WDOG_TOVAL 0x8
#define REFRESH_SEQ0 0xA602
#define REFRESH_SEQ1 0xB480
#define REFRESH ((REFRESH_SEQ1 << 16) | REFRESH_SEQ0)
#define UNLOCK_SEQ0 0xC520
#define UNLOCK_SEQ1 0xD928
#define UNLOCK ((UNLOCK_SEQ1 << 16) | UNLOCK_SEQ0)
#define DEFAULT_TIMEOUT 60
#define MAX_TIMEOUT 128
#define WDOG_CLOCK_RATE 1000
static bool nowayout = WATCHDOG_NOWAYOUT;
module_param(nowayout, bool, 0000);
MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
struct imx7ulp_wdt_device {
struct watchdog_device wdd;
void __iomem *base;
struct clk *clk;
};
static void imx7ulp_wdt_enable(struct watchdog_device *wdog, bool enable)
{
struct imx7ulp_wdt_device *wdt = watchdog_get_drvdata(wdog);
u32 val = readl(wdt->base + WDOG_CS);
writel(UNLOCK, wdt->base + WDOG_CNT);
if (enable)
writel(val | WDOG_CS_EN, wdt->base + WDOG_CS);
else
writel(val & ~WDOG_CS_EN, wdt->base + WDOG_CS);
}
static bool imx7ulp_wdt_is_enabled(void __iomem *base)
{
u32 val = readl(base + WDOG_CS);
return val & WDOG_CS_EN;
}
static int imx7ulp_wdt_ping(struct watchdog_device *wdog)
{
struct imx7ulp_wdt_device *wdt = watchdog_get_drvdata(wdog);
writel(REFRESH, wdt->base + WDOG_CNT);
return 0;
}
static int imx7ulp_wdt_start(struct watchdog_device *wdog)
{
imx7ulp_wdt_enable(wdog, true);
return 0;
}
static int imx7ulp_wdt_stop(struct watchdog_device *wdog)
{
imx7ulp_wdt_enable(wdog, false);
return 0;
}
static int imx7ulp_wdt_set_timeout(struct watchdog_device *wdog,
unsigned int timeout)
{
struct imx7ulp_wdt_device *wdt = watchdog_get_drvdata(wdog);
u32 val = WDOG_CLOCK_RATE * timeout;
writel(UNLOCK, wdt->base + WDOG_CNT);
writel(val, wdt->base + WDOG_TOVAL);
wdog->timeout = timeout;
return 0;
}
static int imx7ulp_wdt_restart(struct watchdog_device *wdog,
unsigned long action, void *data)
{
struct imx7ulp_wdt_device *wdt = watchdog_get_drvdata(wdog);
imx7ulp_wdt_enable(wdog, true);
imx7ulp_wdt_set_timeout(&wdt->wdd, 1);
/* wait for wdog to fire */
while (true)
;
return NOTIFY_DONE;
}
static const struct watchdog_ops imx7ulp_wdt_ops = {
.owner = THIS_MODULE,
.start = imx7ulp_wdt_start,
.stop = imx7ulp_wdt_stop,
.ping = imx7ulp_wdt_ping,
.set_timeout = imx7ulp_wdt_set_timeout,
.restart = imx7ulp_wdt_restart,
};
static const struct watchdog_info imx7ulp_wdt_info = {
.identity = "i.MX7ULP watchdog timer",
.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING |
WDIOF_MAGICCLOSE,
};
static void imx7ulp_wdt_init(void __iomem *base, unsigned int timeout)
{
u32 val;
/* unlock the wdog for reconfiguration */
writel_relaxed(UNLOCK_SEQ0, base + WDOG_CNT);
writel_relaxed(UNLOCK_SEQ1, base + WDOG_CNT);
/* set an initial timeout value in TOVAL */
writel(timeout, base + WDOG_TOVAL);
/* enable 32bit command sequence and reconfigure */
val = WDOG_CS_CMD32EN | WDOG_CS_CLK | WDOG_CS_UPDATE;
writel(val, base + WDOG_CS);
}
static void imx7ulp_wdt_action(void *data)
{
clk_disable_unprepare(data);
}
static int imx7ulp_wdt_probe(struct platform_device *pdev)
{
struct imx7ulp_wdt_device *imx7ulp_wdt;
struct device *dev = &pdev->dev;
struct watchdog_device *wdog;
int ret;
imx7ulp_wdt = devm_kzalloc(dev, sizeof(*imx7ulp_wdt), GFP_KERNEL);
if (!imx7ulp_wdt)
return -ENOMEM;
platform_set_drvdata(pdev, imx7ulp_wdt);
imx7ulp_wdt->base = devm_platform_ioremap_resource(pdev, 0);
if (IS_ERR(imx7ulp_wdt->base))
return PTR_ERR(imx7ulp_wdt->base);
imx7ulp_wdt->clk = devm_clk_get(dev, NULL);
if (IS_ERR(imx7ulp_wdt->clk)) {
dev_err(dev, "Failed to get watchdog clock\n");
return PTR_ERR(imx7ulp_wdt->clk);
}
ret = clk_prepare_enable(imx7ulp_wdt->clk);
if (ret)
return ret;
ret = devm_add_action_or_reset(dev, imx7ulp_wdt_action, imx7ulp_wdt->clk);
if (ret)
return ret;
wdog = &imx7ulp_wdt->wdd;
wdog->info = &imx7ulp_wdt_info;
wdog->ops = &imx7ulp_wdt_ops;
wdog->min_timeout = 1;
wdog->max_timeout = MAX_TIMEOUT;
wdog->parent = dev;
wdog->timeout = DEFAULT_TIMEOUT;
watchdog_init_timeout(wdog, 0, dev);
watchdog_stop_on_reboot(wdog);
watchdog_stop_on_unregister(wdog);
watchdog_set_drvdata(wdog, imx7ulp_wdt);
imx7ulp_wdt_init(imx7ulp_wdt->base, wdog->timeout * WDOG_CLOCK_RATE);
return devm_watchdog_register_device(dev, wdog);
}
static int __maybe_unused imx7ulp_wdt_suspend(struct device *dev)
{
struct imx7ulp_wdt_device *imx7ulp_wdt = dev_get_drvdata(dev);
if (watchdog_active(&imx7ulp_wdt->wdd))
imx7ulp_wdt_stop(&imx7ulp_wdt->wdd);
clk_disable_unprepare(imx7ulp_wdt->clk);
return 0;
}
static int __maybe_unused imx7ulp_wdt_resume(struct device *dev)
{
struct imx7ulp_wdt_device *imx7ulp_wdt = dev_get_drvdata(dev);
u32 timeout = imx7ulp_wdt->wdd.timeout * WDOG_CLOCK_RATE;
int ret;
ret = clk_prepare_enable(imx7ulp_wdt->clk);
if (ret)
return ret;
if (imx7ulp_wdt_is_enabled(imx7ulp_wdt->base))
imx7ulp_wdt_init(imx7ulp_wdt->base, timeout);
if (watchdog_active(&imx7ulp_wdt->wdd))
imx7ulp_wdt_start(&imx7ulp_wdt->wdd);
return 0;
}
static SIMPLE_DEV_PM_OPS(imx7ulp_wdt_pm_ops, imx7ulp_wdt_suspend,
imx7ulp_wdt_resume);
static const struct of_device_id imx7ulp_wdt_dt_ids[] = {
{ .compatible = "fsl,imx7ulp-wdt", },
{ /* sentinel */ }
};
MODULE_DEVICE_TABLE(of, imx7ulp_wdt_dt_ids);
static struct platform_driver imx7ulp_wdt_driver = {
.probe = imx7ulp_wdt_probe,
.driver = {
.name = "imx7ulp-wdt",
.pm = &imx7ulp_wdt_pm_ops,
.of_match_table = imx7ulp_wdt_dt_ids,
},
};
module_platform_driver(imx7ulp_wdt_driver);
MODULE_AUTHOR("Anson Huang <Anson.Huang@nxp.com>");
MODULE_DESCRIPTION("Freescale i.MX7ULP watchdog driver");
MODULE_LICENSE("GPL v2");