watchdog: bcm281xx: Watchdog Driver

This commit adds support for the watchdog timer used on the BCM281xx
family of SoCs.

Signed-off-by: Markus Mayer <markus.mayer@linaro.org>
Reviewed-by: Matt Porter <matt.porter@linaro.org>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
This commit is contained in:
Markus Mayer 2013-11-22 14:56:03 -08:00 committed by Wim Van Sebroeck
parent 2c34d59916
commit 6adb730dc2
4 changed files with 283 additions and 0 deletions

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@ -126,3 +126,5 @@ CONFIG_CRC7=y
CONFIG_XZ_DEC=y
CONFIG_AVERAGE=y
CONFIG_PINCTRL_CAPRI=y
CONFIG_WATCHDOG=y
CONFIG_BCM_KONA_WDT=y

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@ -1139,6 +1139,18 @@ config BCM2835_WDT
To compile this driver as a loadable module, choose M here.
The module will be called bcm2835_wdt.
config BCM_KONA_WDT
tristate "BCM Kona Watchdog"
depends on ARCH_BCM
select WATCHDOG_CORE
help
Support for the watchdog timer on the following Broadcom BCM281xx
family, which includes BCM11130, BCM11140, BCM11351, BCM28145 and
BCM28155 variants.
Say 'Y' or 'M' here to enable the driver. The module will be called
bcm_kona_wdt.
config LANTIQ_WDT
tristate "Lantiq SoC watchdog"
depends on LANTIQ

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@ -57,6 +57,7 @@ obj-$(CONFIG_RETU_WATCHDOG) += retu_wdt.o
obj-$(CONFIG_BCM2835_WDT) += bcm2835_wdt.o
obj-$(CONFIG_MOXART_WDT) += moxart_wdt.o
obj-$(CONFIG_SIRFSOC_WATCHDOG) += sirfsoc_wdt.o
obj-$(CONFIG_BCM_KONA_WDT) += bcm_kona_wdt.o
# AVR32 Architecture
obj-$(CONFIG_AT32AP700X_WDT) += at32ap700x_wdt.o

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@ -0,0 +1,268 @@
/*
* Copyright (C) 2013 Broadcom Corporation
*
* 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 version 2.
*
* This program is distributed "as is" WITHOUT ANY WARRANTY of any
* kind, whether express or implied; without even the implied warranty
* of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*/
#include <linux/delay.h>
#include <linux/err.h>
#include <linux/io.h>
#include <linux/module.h>
#include <linux/of_address.h>
#include <linux/platform_device.h>
#include <linux/watchdog.h>
#define SECWDOG_CTRL_REG 0x00000000
#define SECWDOG_COUNT_REG 0x00000004
#define SECWDOG_RESERVED_MASK 0x1dffffff
#define SECWDOG_WD_LOAD_FLAG 0x10000000
#define SECWDOG_EN_MASK 0x08000000
#define SECWDOG_SRSTEN_MASK 0x04000000
#define SECWDOG_RES_MASK 0x00f00000
#define SECWDOG_COUNT_MASK 0x000fffff
#define SECWDOG_MAX_COUNT SECWDOG_COUNT_MASK
#define SECWDOG_CLKS_SHIFT 20
#define SECWDOG_MAX_RES 15
#define SECWDOG_DEFAULT_RESOLUTION 4
#define SECWDOG_MAX_TRY 1000
#define SECS_TO_TICKS(x, w) ((x) << (w)->resolution)
#define TICKS_TO_SECS(x, w) ((x) >> (w)->resolution)
#define BCM_KONA_WDT_NAME "bcm_kona_wdt"
struct bcm_kona_wdt {
void __iomem *base;
/*
* One watchdog tick is 1/(2^resolution) seconds. Resolution can take
* the values 0-15, meaning one tick can be 1s to 30.52us. Our default
* resolution of 4 means one tick is 62.5ms.
*
* The watchdog counter is 20 bits. Depending on resolution, the maximum
* counter value of 0xfffff expires after about 12 days (resolution 0)
* down to only 32s (resolution 15). The default resolution of 4 gives
* us a maximum of about 18 hours and 12 minutes before the watchdog
* times out.
*/
int resolution;
spinlock_t lock;
};
static int secure_register_read(void __iomem *addr)
{
uint32_t val;
unsigned count = 0;
/*
* If the WD_LOAD_FLAG is set, the watchdog counter field is being
* updated in hardware. Once the WD timer is updated in hardware, it
* gets cleared.
*/
do {
if (unlikely(count > 1))
udelay(5);
val = readl_relaxed(addr);
count++;
} while ((val & SECWDOG_WD_LOAD_FLAG) && count < SECWDOG_MAX_TRY);
/* This is the only place we return a negative value. */
if (val & SECWDOG_WD_LOAD_FLAG)
return -ETIMEDOUT;
/* We always mask out reserved bits. */
val &= SECWDOG_RESERVED_MASK;
return val;
}
static int bcm_kona_wdt_ctrl_reg_modify(struct bcm_kona_wdt *wdt,
unsigned mask, unsigned newval)
{
int val;
unsigned long flags;
int ret = 0;
spin_lock_irqsave(&wdt->lock, flags);
val = secure_register_read(wdt->base + SECWDOG_CTRL_REG);
if (val < 0) {
ret = val;
} else {
val &= ~mask;
val |= newval;
writel_relaxed(val, wdt->base + SECWDOG_CTRL_REG);
}
spin_unlock_irqrestore(&wdt->lock, flags);
return ret;
}
static int bcm_kona_wdt_set_resolution_reg(struct bcm_kona_wdt *wdt)
{
if (wdt->resolution > SECWDOG_MAX_RES)
return -EINVAL;
return bcm_kona_wdt_ctrl_reg_modify(wdt, SECWDOG_RES_MASK,
wdt->resolution << SECWDOG_CLKS_SHIFT);
}
static int bcm_kona_wdt_set_timeout_reg(struct watchdog_device *wdog,
unsigned watchdog_flags)
{
struct bcm_kona_wdt *wdt = watchdog_get_drvdata(wdog);
return bcm_kona_wdt_ctrl_reg_modify(wdt, SECWDOG_COUNT_MASK,
SECS_TO_TICKS(wdog->timeout, wdt) |
watchdog_flags);
}
static int bcm_kona_wdt_set_timeout(struct watchdog_device *wdog,
unsigned int t)
{
wdog->timeout = t;
return 0;
}
static unsigned int bcm_kona_wdt_get_timeleft(struct watchdog_device *wdog)
{
struct bcm_kona_wdt *wdt = watchdog_get_drvdata(wdog);
int val;
unsigned long flags;
spin_lock_irqsave(&wdt->lock, flags);
val = secure_register_read(wdt->base + SECWDOG_COUNT_REG);
spin_unlock_irqrestore(&wdt->lock, flags);
if (val < 0)
return val;
return TICKS_TO_SECS(val & SECWDOG_COUNT_MASK, wdt);
}
static int bcm_kona_wdt_start(struct watchdog_device *wdog)
{
return bcm_kona_wdt_set_timeout_reg(wdog,
SECWDOG_EN_MASK | SECWDOG_SRSTEN_MASK);
}
static int bcm_kona_wdt_stop(struct watchdog_device *wdog)
{
struct bcm_kona_wdt *wdt = watchdog_get_drvdata(wdog);
return bcm_kona_wdt_ctrl_reg_modify(wdt, SECWDOG_EN_MASK |
SECWDOG_SRSTEN_MASK, 0);
}
static struct watchdog_ops bcm_kona_wdt_ops = {
.owner = THIS_MODULE,
.start = bcm_kona_wdt_start,
.stop = bcm_kona_wdt_stop,
.set_timeout = bcm_kona_wdt_set_timeout,
.get_timeleft = bcm_kona_wdt_get_timeleft,
};
static struct watchdog_info bcm_kona_wdt_info = {
.options = WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE |
WDIOF_KEEPALIVEPING,
.identity = "Broadcom Kona Watchdog Timer",
};
static struct watchdog_device bcm_kona_wdt_wdd = {
.info = &bcm_kona_wdt_info,
.ops = &bcm_kona_wdt_ops,
.min_timeout = 1,
.max_timeout = SECWDOG_MAX_COUNT >> SECWDOG_DEFAULT_RESOLUTION,
.timeout = SECWDOG_MAX_COUNT >> SECWDOG_DEFAULT_RESOLUTION,
};
static void bcm_kona_wdt_shutdown(struct platform_device *pdev)
{
bcm_kona_wdt_stop(&bcm_kona_wdt_wdd);
}
static int bcm_kona_wdt_probe(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
struct bcm_kona_wdt *wdt;
struct resource *res;
int ret;
wdt = devm_kzalloc(dev, sizeof(*wdt), GFP_KERNEL);
if (!wdt)
return -ENOMEM;
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
wdt->base = devm_ioremap_resource(dev, res);
if (IS_ERR(wdt->base))
return -ENODEV;
wdt->resolution = SECWDOG_DEFAULT_RESOLUTION;
ret = bcm_kona_wdt_set_resolution_reg(wdt);
if (ret) {
dev_err(dev, "Failed to set resolution (error: %d)", ret);
return ret;
}
spin_lock_init(&wdt->lock);
platform_set_drvdata(pdev, wdt);
watchdog_set_drvdata(&bcm_kona_wdt_wdd, wdt);
ret = bcm_kona_wdt_set_timeout_reg(&bcm_kona_wdt_wdd, 0);
if (ret) {
dev_err(dev, "Failed set watchdog timeout");
return ret;
}
ret = watchdog_register_device(&bcm_kona_wdt_wdd);
if (ret) {
dev_err(dev, "Failed to register watchdog device");
return ret;
}
dev_dbg(dev, "Broadcom Kona Watchdog Timer");
return 0;
}
static int bcm_kona_wdt_remove(struct platform_device *pdev)
{
bcm_kona_wdt_shutdown(pdev);
watchdog_unregister_device(&bcm_kona_wdt_wdd);
dev_dbg(&pdev->dev, "Watchdog driver disabled");
return 0;
}
static const struct of_device_id bcm_kona_wdt_of_match[] = {
{ .compatible = "brcm,kona-wdt", },
{},
};
MODULE_DEVICE_TABLE(of, bcm_kona_wdt_of_match);
static struct platform_driver bcm_kona_wdt_driver = {
.driver = {
.name = BCM_KONA_WDT_NAME,
.owner = THIS_MODULE,
.of_match_table = bcm_kona_wdt_of_match,
},
.probe = bcm_kona_wdt_probe,
.remove = bcm_kona_wdt_remove,
.shutdown = bcm_kona_wdt_shutdown,
};
module_platform_driver(bcm_kona_wdt_driver);
MODULE_ALIAS("platform:" BCM_KONA_WDT_NAME);
MODULE_AUTHOR("Markus Mayer <mmayer@broadcom.com>");
MODULE_DESCRIPTION("Broadcom Kona Watchdog Driver");
MODULE_LICENSE("GPL v2");