linux/drivers/watchdog/tegra_wdt.c
Guenter Roeck 4b448c96a7 watchdog: tegra_wdt: Convert to use device managed functions
Use device managed functions to simplify error handling, reduce
source code size, improve readability, and reduce the likelyhood of bugs.

The conversion was done automatically with coccinelle using the
following semantic patches. The semantic patches and the scripts used
to generate this commit log are available at
https://github.com/groeck/coccinelle-patches

- Use devm_watchdog_register_driver() to register watchdog device

Cc: Stephen Warren <swarren@wwwdotorg.org>
Cc: Thierry Reding <thierry.reding@gmail.com>
Cc: Alexandre Courbot <gnurou@gmail.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Acked-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
2017-02-24 14:00:23 -08:00

303 lines
7.7 KiB
C

/*
* Copyright (c) 2014, NVIDIA CORPORATION. All rights reserved.
*
* This program is free software; you can redistribute it and/or modify it
* under the terms and conditions of the GNU General Public License,
* version 2, as published by the Free Software Foundation.
*
* This program is distributed in the hope it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
* more details.
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/watchdog.h>
/* minimum and maximum watchdog trigger timeout, in seconds */
#define MIN_WDT_TIMEOUT 1
#define MAX_WDT_TIMEOUT 255
/*
* Base of the WDT registers, from the timer base address. There are
* actually 5 watchdogs that can be configured (by pairing with an available
* timer), at bases 0x100 + (WDT ID) * 0x20, where WDT ID is 0 through 4.
* This driver only configures the first watchdog (WDT ID 0).
*/
#define WDT_BASE 0x100
#define WDT_ID 0
/*
* Register base of the timer that's selected for pairing with the watchdog.
* This driver arbitrarily uses timer 5, which is currently unused by
* other drivers (in particular, the Tegra clocksource driver). If this
* needs to change, take care that the new timer is not used by the
* clocksource driver.
*/
#define WDT_TIMER_BASE 0x60
#define WDT_TIMER_ID 5
/* WDT registers */
#define WDT_CFG 0x0
#define WDT_CFG_PERIOD_SHIFT 4
#define WDT_CFG_PERIOD_MASK 0xff
#define WDT_CFG_INT_EN (1 << 12)
#define WDT_CFG_PMC2CAR_RST_EN (1 << 15)
#define WDT_STS 0x4
#define WDT_STS_COUNT_SHIFT 4
#define WDT_STS_COUNT_MASK 0xff
#define WDT_STS_EXP_SHIFT 12
#define WDT_STS_EXP_MASK 0x3
#define WDT_CMD 0x8
#define WDT_CMD_START_COUNTER (1 << 0)
#define WDT_CMD_DISABLE_COUNTER (1 << 1)
#define WDT_UNLOCK (0xc)
#define WDT_UNLOCK_PATTERN (0xc45a << 0)
/* Timer registers */
#define TIMER_PTV 0x0
#define TIMER_EN (1 << 31)
#define TIMER_PERIODIC (1 << 30)
struct tegra_wdt {
struct watchdog_device wdd;
void __iomem *wdt_regs;
void __iomem *tmr_regs;
};
#define WDT_HEARTBEAT 120
static int heartbeat = WDT_HEARTBEAT;
module_param(heartbeat, int, 0);
MODULE_PARM_DESC(heartbeat,
"Watchdog heartbeats in seconds. (default = "
__MODULE_STRING(WDT_HEARTBEAT) ")");
static bool nowayout = WATCHDOG_NOWAYOUT;
module_param(nowayout, bool, 0);
MODULE_PARM_DESC(nowayout,
"Watchdog cannot be stopped once started (default="
__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
static int tegra_wdt_start(struct watchdog_device *wdd)
{
struct tegra_wdt *wdt = watchdog_get_drvdata(wdd);
u32 val;
/*
* This thing has a fixed 1MHz clock. Normally, we would set the
* period to 1 second by writing 1000000ul, but the watchdog system
* reset actually occurs on the 4th expiration of this counter,
* so we set the period to 1/4 of this amount.
*/
val = 1000000ul / 4;
val |= (TIMER_EN | TIMER_PERIODIC);
writel(val, wdt->tmr_regs + TIMER_PTV);
/*
* Set number of periods and start counter.
*
* Interrupt handler is not required for user space
* WDT accesses, since the caller is responsible to ping the
* WDT to reset the counter before expiration, through ioctls.
*/
val = WDT_TIMER_ID |
(wdd->timeout << WDT_CFG_PERIOD_SHIFT) |
WDT_CFG_PMC2CAR_RST_EN;
writel(val, wdt->wdt_regs + WDT_CFG);
writel(WDT_CMD_START_COUNTER, wdt->wdt_regs + WDT_CMD);
return 0;
}
static int tegra_wdt_stop(struct watchdog_device *wdd)
{
struct tegra_wdt *wdt = watchdog_get_drvdata(wdd);
writel(WDT_UNLOCK_PATTERN, wdt->wdt_regs + WDT_UNLOCK);
writel(WDT_CMD_DISABLE_COUNTER, wdt->wdt_regs + WDT_CMD);
writel(0, wdt->tmr_regs + TIMER_PTV);
return 0;
}
static int tegra_wdt_ping(struct watchdog_device *wdd)
{
struct tegra_wdt *wdt = watchdog_get_drvdata(wdd);
writel(WDT_CMD_START_COUNTER, wdt->wdt_regs + WDT_CMD);
return 0;
}
static int tegra_wdt_set_timeout(struct watchdog_device *wdd,
unsigned int timeout)
{
wdd->timeout = timeout;
if (watchdog_active(wdd)) {
tegra_wdt_stop(wdd);
return tegra_wdt_start(wdd);
}
return 0;
}
static unsigned int tegra_wdt_get_timeleft(struct watchdog_device *wdd)
{
struct tegra_wdt *wdt = watchdog_get_drvdata(wdd);
u32 val;
int count;
int exp;
val = readl(wdt->wdt_regs + WDT_STS);
/* Current countdown (from timeout) */
count = (val >> WDT_STS_COUNT_SHIFT) & WDT_STS_COUNT_MASK;
/* Number of expirations (we are waiting for the 4th expiration) */
exp = (val >> WDT_STS_EXP_SHIFT) & WDT_STS_EXP_MASK;
/*
* The entire thing is divided by 4 because we are ticking down 4 times
* faster due to needing to wait for the 4th expiration.
*/
return (((3 - exp) * wdd->timeout) + count) / 4;
}
static const struct watchdog_info tegra_wdt_info = {
.options = WDIOF_SETTIMEOUT |
WDIOF_MAGICCLOSE |
WDIOF_KEEPALIVEPING,
.firmware_version = 0,
.identity = "Tegra Watchdog",
};
static const struct watchdog_ops tegra_wdt_ops = {
.owner = THIS_MODULE,
.start = tegra_wdt_start,
.stop = tegra_wdt_stop,
.ping = tegra_wdt_ping,
.set_timeout = tegra_wdt_set_timeout,
.get_timeleft = tegra_wdt_get_timeleft,
};
static int tegra_wdt_probe(struct platform_device *pdev)
{
struct watchdog_device *wdd;
struct tegra_wdt *wdt;
struct resource *res;
void __iomem *regs;
int ret;
/* This is the timer base. */
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
regs = devm_ioremap_resource(&pdev->dev, res);
if (IS_ERR(regs))
return PTR_ERR(regs);
/*
* Allocate our watchdog driver data, which has the
* struct watchdog_device nested within it.
*/
wdt = devm_kzalloc(&pdev->dev, sizeof(*wdt), GFP_KERNEL);
if (!wdt)
return -ENOMEM;
/* Initialize struct tegra_wdt. */
wdt->wdt_regs = regs + WDT_BASE;
wdt->tmr_regs = regs + WDT_TIMER_BASE;
/* Initialize struct watchdog_device. */
wdd = &wdt->wdd;
wdd->timeout = heartbeat;
wdd->info = &tegra_wdt_info;
wdd->ops = &tegra_wdt_ops;
wdd->min_timeout = MIN_WDT_TIMEOUT;
wdd->max_timeout = MAX_WDT_TIMEOUT;
wdd->parent = &pdev->dev;
watchdog_set_drvdata(wdd, wdt);
watchdog_set_nowayout(wdd, nowayout);
ret = devm_watchdog_register_device(&pdev->dev, wdd);
if (ret) {
dev_err(&pdev->dev,
"failed to register watchdog device\n");
return ret;
}
platform_set_drvdata(pdev, wdt);
dev_info(&pdev->dev,
"initialized (heartbeat = %d sec, nowayout = %d)\n",
heartbeat, nowayout);
return 0;
}
static int tegra_wdt_remove(struct platform_device *pdev)
{
struct tegra_wdt *wdt = platform_get_drvdata(pdev);
tegra_wdt_stop(&wdt->wdd);
dev_info(&pdev->dev, "removed wdt\n");
return 0;
}
#ifdef CONFIG_PM_SLEEP
static int tegra_wdt_runtime_suspend(struct device *dev)
{
struct tegra_wdt *wdt = dev_get_drvdata(dev);
if (watchdog_active(&wdt->wdd))
tegra_wdt_stop(&wdt->wdd);
return 0;
}
static int tegra_wdt_runtime_resume(struct device *dev)
{
struct tegra_wdt *wdt = dev_get_drvdata(dev);
if (watchdog_active(&wdt->wdd))
tegra_wdt_start(&wdt->wdd);
return 0;
}
#endif
static const struct of_device_id tegra_wdt_of_match[] = {
{ .compatible = "nvidia,tegra30-timer", },
{ },
};
MODULE_DEVICE_TABLE(of, tegra_wdt_of_match);
static const struct dev_pm_ops tegra_wdt_pm_ops = {
SET_SYSTEM_SLEEP_PM_OPS(tegra_wdt_runtime_suspend,
tegra_wdt_runtime_resume)
};
static struct platform_driver tegra_wdt_driver = {
.probe = tegra_wdt_probe,
.remove = tegra_wdt_remove,
.driver = {
.name = "tegra-wdt",
.pm = &tegra_wdt_pm_ops,
.of_match_table = tegra_wdt_of_match,
},
};
module_platform_driver(tegra_wdt_driver);
MODULE_AUTHOR("NVIDIA Corporation");
MODULE_DESCRIPTION("Tegra Watchdog Driver");
MODULE_LICENSE("GPL v2");