378 lines
8.7 KiB
C
378 lines
8.7 KiB
C
/*
|
|
* Watchdog driver for Cortina Systems Gemini SoC
|
|
*
|
|
* Copyright (C) 2009 Paulius Zaleckas <paulius.zaleckas@teltonika.lt>
|
|
*
|
|
* This program is free software; you can redistribute it and/or modify
|
|
* it under the terms of the GNU General Public License version 2 as
|
|
* published by the Free Software Foundation.
|
|
*/
|
|
|
|
#include <linux/kernel.h>
|
|
#include <linux/init.h>
|
|
#include <linux/module.h>
|
|
#include <linux/io.h>
|
|
#include <linux/fs.h>
|
|
#include <linux/uaccess.h>
|
|
#include <linux/miscdevice.h>
|
|
#include <linux/platform_device.h>
|
|
#include <linux/watchdog.h>
|
|
#include <linux/slab.h>
|
|
|
|
#define GEMINI_WDCOUNTER 0x0
|
|
#define GEMINI_WDLOAD 0x4
|
|
#define GEMINI_WDRESTART 0x8
|
|
|
|
#define WDRESTART_MAGIC 0x5AB9
|
|
|
|
#define GEMINI_WDCR 0xC
|
|
|
|
#define WDCR_CLOCK_5MHZ (1 << 4)
|
|
#define WDCR_SYS_RST (1 << 1)
|
|
#define WDCR_ENABLE (1 << 0)
|
|
|
|
#define WDT_CLOCK 5000000 /* 5 MHz */
|
|
#define WDT_DEFAULT_TIMEOUT 13
|
|
#define WDT_MAX_TIMEOUT (0xFFFFFFFF / WDT_CLOCK)
|
|
|
|
/* status bits */
|
|
#define WDT_ACTIVE 0
|
|
#define WDT_OK_TO_CLOSE 1
|
|
|
|
static unsigned int timeout = WDT_DEFAULT_TIMEOUT;
|
|
static int nowayout = WATCHDOG_NOWAYOUT;
|
|
|
|
static DEFINE_SPINLOCK(gemini_wdt_lock);
|
|
|
|
static struct platform_device *gemini_wdt_dev;
|
|
|
|
struct gemini_wdt_struct {
|
|
struct resource *res;
|
|
struct device *dev;
|
|
void __iomem *base;
|
|
unsigned long status;
|
|
};
|
|
|
|
static struct watchdog_info gemini_wdt_info = {
|
|
.identity = "Gemini watchdog",
|
|
.options = WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING |
|
|
WDIOF_SETTIMEOUT,
|
|
};
|
|
|
|
/* Disable the watchdog. */
|
|
static void gemini_wdt_stop(struct gemini_wdt_struct *gemini_wdt)
|
|
{
|
|
spin_lock(&gemini_wdt_lock);
|
|
|
|
__raw_writel(0, gemini_wdt->base + GEMINI_WDCR);
|
|
|
|
clear_bit(WDT_ACTIVE, &gemini_wdt->status);
|
|
|
|
spin_unlock(&gemini_wdt_lock);
|
|
}
|
|
|
|
/* Service the watchdog */
|
|
static void gemini_wdt_service(struct gemini_wdt_struct *gemini_wdt)
|
|
{
|
|
__raw_writel(WDRESTART_MAGIC, gemini_wdt->base + GEMINI_WDRESTART);
|
|
}
|
|
|
|
/* Enable and reset the watchdog. */
|
|
static void gemini_wdt_start(struct gemini_wdt_struct *gemini_wdt)
|
|
{
|
|
spin_lock(&gemini_wdt_lock);
|
|
|
|
__raw_writel(timeout * WDT_CLOCK, gemini_wdt->base + GEMINI_WDLOAD);
|
|
|
|
gemini_wdt_service(gemini_wdt);
|
|
|
|
/* set clock before enabling */
|
|
__raw_writel(WDCR_CLOCK_5MHZ | WDCR_SYS_RST,
|
|
gemini_wdt->base + GEMINI_WDCR);
|
|
|
|
__raw_writel(WDCR_CLOCK_5MHZ | WDCR_SYS_RST | WDCR_ENABLE,
|
|
gemini_wdt->base + GEMINI_WDCR);
|
|
|
|
set_bit(WDT_ACTIVE, &gemini_wdt->status);
|
|
|
|
spin_unlock(&gemini_wdt_lock);
|
|
}
|
|
|
|
/* Watchdog device is opened, and watchdog starts running. */
|
|
static int gemini_wdt_open(struct inode *inode, struct file *file)
|
|
{
|
|
struct gemini_wdt_struct *gemini_wdt = platform_get_drvdata(gemini_wdt_dev);
|
|
|
|
if (test_bit(WDT_ACTIVE, &gemini_wdt->status))
|
|
return -EBUSY;
|
|
|
|
file->private_data = gemini_wdt;
|
|
|
|
gemini_wdt_start(gemini_wdt);
|
|
|
|
return nonseekable_open(inode, file);
|
|
}
|
|
|
|
/* Close the watchdog device. */
|
|
static int gemini_wdt_close(struct inode *inode, struct file *file)
|
|
{
|
|
struct gemini_wdt_struct *gemini_wdt = file->private_data;
|
|
|
|
/* Disable the watchdog if possible */
|
|
if (test_bit(WDT_OK_TO_CLOSE, &gemini_wdt->status))
|
|
gemini_wdt_stop(gemini_wdt);
|
|
else
|
|
dev_warn(gemini_wdt->dev, "Device closed unexpectedly - timer will not stop\n");
|
|
|
|
return 0;
|
|
}
|
|
|
|
/* Handle commands from user-space. */
|
|
static long gemini_wdt_ioctl(struct file *file, unsigned int cmd,
|
|
unsigned long arg)
|
|
{
|
|
struct gemini_wdt_struct *gemini_wdt = file->private_data;
|
|
|
|
int value;
|
|
|
|
switch (cmd) {
|
|
case WDIOC_KEEPALIVE:
|
|
gemini_wdt_service(gemini_wdt);
|
|
return 0;
|
|
|
|
case WDIOC_GETSUPPORT:
|
|
return copy_to_user((struct watchdog_info *)arg, &gemini_wdt_info,
|
|
sizeof(gemini_wdt_info)) ? -EFAULT : 0;
|
|
|
|
case WDIOC_SETTIMEOUT:
|
|
if (get_user(value, (int *)arg))
|
|
return -EFAULT;
|
|
|
|
if ((value < 1) || (value > WDT_MAX_TIMEOUT))
|
|
return -EINVAL;
|
|
|
|
timeout = value;
|
|
|
|
/* restart wdt to use new timeout */
|
|
gemini_wdt_stop(gemini_wdt);
|
|
gemini_wdt_start(gemini_wdt);
|
|
|
|
/* Fall through */
|
|
case WDIOC_GETTIMEOUT:
|
|
return put_user(timeout, (int *)arg);
|
|
|
|
case WDIOC_GETTIMELEFT:
|
|
value = __raw_readl(gemini_wdt->base + GEMINI_WDCOUNTER);
|
|
return put_user(value / WDT_CLOCK, (int *)arg);
|
|
|
|
default:
|
|
return -ENOTTY;
|
|
}
|
|
}
|
|
|
|
/* Refresh the watchdog whenever device is written to. */
|
|
static ssize_t gemini_wdt_write(struct file *file, const char *data,
|
|
size_t len, loff_t *ppos)
|
|
{
|
|
struct gemini_wdt_struct *gemini_wdt = file->private_data;
|
|
|
|
if (len) {
|
|
if (!nowayout) {
|
|
size_t i;
|
|
|
|
clear_bit(WDT_OK_TO_CLOSE, &gemini_wdt->status);
|
|
for (i = 0; i != len; i++) {
|
|
char c;
|
|
|
|
if (get_user(c, data + i))
|
|
return -EFAULT;
|
|
if (c == 'V')
|
|
set_bit(WDT_OK_TO_CLOSE,
|
|
&gemini_wdt->status);
|
|
}
|
|
}
|
|
gemini_wdt_service(gemini_wdt);
|
|
}
|
|
|
|
return len;
|
|
}
|
|
|
|
static const struct file_operations gemini_wdt_fops = {
|
|
.owner = THIS_MODULE,
|
|
.llseek = no_llseek,
|
|
.unlocked_ioctl = gemini_wdt_ioctl,
|
|
.open = gemini_wdt_open,
|
|
.release = gemini_wdt_close,
|
|
.write = gemini_wdt_write,
|
|
};
|
|
|
|
static struct miscdevice gemini_wdt_miscdev = {
|
|
.minor = WATCHDOG_MINOR,
|
|
.name = "watchdog",
|
|
.fops = &gemini_wdt_fops,
|
|
};
|
|
|
|
static void gemini_wdt_shutdown(struct platform_device *pdev)
|
|
{
|
|
struct gemini_wdt_struct *gemini_wdt = platform_get_drvdata(pdev);
|
|
|
|
gemini_wdt_stop(gemini_wdt);
|
|
}
|
|
|
|
static int gemini_wdt_probe(struct platform_device *pdev)
|
|
{
|
|
int ret;
|
|
int res_size;
|
|
struct resource *res;
|
|
void __iomem *base;
|
|
struct gemini_wdt_struct *gemini_wdt;
|
|
unsigned int reg;
|
|
|
|
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
|
|
if (!res) {
|
|
dev_err(&pdev->dev, "can't get device resources\n");
|
|
return -ENODEV;
|
|
}
|
|
|
|
res_size = resource_size(res);
|
|
if (!request_mem_region(res->start, res_size, res->name)) {
|
|
dev_err(&pdev->dev, "can't allocate %d bytes at %d address\n",
|
|
res_size, res->start);
|
|
return -ENOMEM;
|
|
}
|
|
|
|
base = ioremap(res->start, res_size);
|
|
if (!base) {
|
|
dev_err(&pdev->dev, "ioremap failed\n");
|
|
ret = -EIO;
|
|
goto fail0;
|
|
}
|
|
|
|
gemini_wdt = kzalloc(sizeof(struct gemini_wdt_struct), GFP_KERNEL);
|
|
if (!gemini_wdt) {
|
|
dev_err(&pdev->dev, "can't allocate interface\n");
|
|
ret = -ENOMEM;
|
|
goto fail1;
|
|
}
|
|
|
|
/* Setup gemini_wdt driver structure */
|
|
gemini_wdt->base = base;
|
|
gemini_wdt->res = res;
|
|
|
|
/* Set up platform driver data */
|
|
platform_set_drvdata(pdev, gemini_wdt);
|
|
gemini_wdt_dev = pdev;
|
|
|
|
if (gemini_wdt_miscdev.parent) {
|
|
ret = -EBUSY;
|
|
goto fail2;
|
|
}
|
|
|
|
gemini_wdt_miscdev.parent = &pdev->dev;
|
|
|
|
reg = __raw_readw(gemini_wdt->base + GEMINI_WDCR);
|
|
if (reg & WDCR_ENABLE) {
|
|
/* Watchdog was enabled by the bootloader, disable it. */
|
|
reg &= ~(WDCR_ENABLE);
|
|
__raw_writel(reg, gemini_wdt->base + GEMINI_WDCR);
|
|
}
|
|
|
|
ret = misc_register(&gemini_wdt_miscdev);
|
|
if (ret)
|
|
goto fail2;
|
|
|
|
return 0;
|
|
|
|
fail2:
|
|
platform_set_drvdata(pdev, NULL);
|
|
kfree(gemini_wdt);
|
|
fail1:
|
|
iounmap(base);
|
|
fail0:
|
|
release_mem_region(res->start, res_size);
|
|
|
|
return ret;
|
|
}
|
|
|
|
static int gemini_wdt_remove(struct platform_device *pdev)
|
|
{
|
|
struct gemini_wdt_struct *gemini_wdt = platform_get_drvdata(pdev);
|
|
|
|
platform_set_drvdata(pdev, NULL);
|
|
misc_deregister(&gemini_wdt_miscdev);
|
|
gemini_wdt_dev = NULL;
|
|
iounmap(gemini_wdt->base);
|
|
release_mem_region(gemini_wdt->res->start, resource_size(gemini_wdt->res));
|
|
|
|
kfree(gemini_wdt);
|
|
|
|
return 0;
|
|
}
|
|
|
|
#ifdef CONFIG_PM
|
|
static int gemini_wdt_suspend(struct platform_device *pdev, pm_message_t message)
|
|
{
|
|
struct gemini_wdt_struct *gemini_wdt = platform_get_drvdata(pdev);
|
|
unsigned int reg;
|
|
|
|
reg = __raw_readw(gemini_wdt->base + GEMINI_WDCR);
|
|
reg &= ~(WDCR_WDENABLE);
|
|
__raw_writel(reg, gemini_wdt->base + GEMINI_WDCR);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int gemini_wdt_resume(struct platform_device *pdev)
|
|
{
|
|
struct gemini_wdt_struct *gemini_wdt = platform_get_drvdata(pdev);
|
|
unsigned int reg;
|
|
|
|
if (gemini_wdt->status) {
|
|
reg = __raw_readw(gemini_wdt->base + GEMINI_WDCR);
|
|
reg |= WDCR_WDENABLE;
|
|
__raw_writel(reg, gemini_wdt->base + GEMINI_WDCR);
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
#else
|
|
#define gemini_wdt_suspend NULL
|
|
#define gemini_wdt_resume NULL
|
|
#endif
|
|
|
|
static struct platform_driver gemini_wdt_driver = {
|
|
.probe = gemini_wdt_probe,
|
|
.remove = gemini_wdt_remove,
|
|
.shutdown = gemini_wdt_shutdown,
|
|
.suspend = gemini_wdt_suspend,
|
|
.resume = gemini_wdt_resume,
|
|
.driver = {
|
|
.name = "gemini-wdt",
|
|
.owner = THIS_MODULE,
|
|
},
|
|
};
|
|
|
|
static int __init gemini_wdt_init(void)
|
|
{
|
|
return platform_driver_probe(&gemini_wdt_driver, gemini_wdt_probe);
|
|
}
|
|
|
|
static void __exit gemini_wdt_exit(void)
|
|
{
|
|
platform_driver_unregister(&gemini_wdt_driver);
|
|
}
|
|
|
|
module_init(gemini_wdt_init);
|
|
module_exit(gemini_wdt_exit);
|
|
|
|
module_param(timeout, uint, 0);
|
|
MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds");
|
|
|
|
module_param(nowayout, int, 0);
|
|
MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started");
|
|
|
|
MODULE_AUTHOR("Paulius Zaleckas");
|
|
MODULE_DESCRIPTION("Watchdog driver for Gemini");
|
|
MODULE_LICENSE("GPL");
|
|
MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
|
|
MODULE_ALIAS("platform:gemini-wdt");
|