linux/drivers/watchdog/bcm63xx_wdt.c
Jean Delvare 487722cf2d watchdog: Get rid of MODULE_ALIAS_MISCDEV statements
I just can't find any value in MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR)
and MODULE_ALIAS_MISCDEV(TEMP_MINOR) statements.

Either the device is enumerated and the driver already has a module
alias (e.g. PCI, USB etc.) that will get the right driver loaded
automatically.

Or the device is not enumerated and loading its driver will lead to
more or less intrusive hardware poking. Such hardware poking should be
limited to a bare minimum, so the user should really decide which
drivers should be tried and in what order. Trying them all in
arbitrary order can't do any good.

On top of that, loading that many drivers at once bloats the kernel
log. Also many drivers will stay loaded afterward, bloating the output
of "lsmod" and wasting memory. Some modules (cs5535_mfgpt which gets
loaded as a dependency) can't even be unloaded!

If defining char-major-10-130 is needed then it should happen in
user-space.

Signed-off-by: Jean Delvare <jdelvare@suse.de>
Acked-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
Cc: Stephen Warren <swarren@wwwdotorg.org>
Cc: Mike Frysinger <vapier.adi@gmail.com>
Cc: Wan ZongShun <mcuos.com@gmail.com>
Cc: Ben Dooks <ben-linux@fluff.org>
Cc: Kukjin Kim <kgene.kim@samsung.com>
Cc: Zwane Mwaikambo <zwane@arm.linux.org.uk>
Cc: Jim Cromie <jim.cromie@gmail.com>
2013-11-17 19:38:13 +01:00

321 lines
7.0 KiB
C

/*
* Broadcom BCM63xx SoC watchdog driver
*
* Copyright (C) 2007, Miguel Gaio <miguel.gaio@efixo.com>
* Copyright (C) 2008, Florian Fainelli <florian@openwrt.org>
*
* 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; either version
* 2 of the License, or (at your option) any later version.
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/bitops.h>
#include <linux/errno.h>
#include <linux/fs.h>
#include <linux/init.h>
#include <linux/io.h>
#include <linux/kernel.h>
#include <linux/miscdevice.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/types.h>
#include <linux/uaccess.h>
#include <linux/watchdog.h>
#include <linux/timer.h>
#include <linux/jiffies.h>
#include <linux/interrupt.h>
#include <linux/ptrace.h>
#include <linux/resource.h>
#include <linux/platform_device.h>
#include <bcm63xx_cpu.h>
#include <bcm63xx_io.h>
#include <bcm63xx_regs.h>
#include <bcm63xx_timer.h>
#define PFX KBUILD_MODNAME
#define WDT_HZ 50000000 /* Fclk */
#define WDT_DEFAULT_TIME 30 /* seconds */
#define WDT_MAX_TIME 256 /* seconds */
static struct {
void __iomem *regs;
struct timer_list timer;
int default_ticks;
unsigned long inuse;
atomic_t ticks;
} bcm63xx_wdt_device;
static int expect_close;
static int wdt_time = WDT_DEFAULT_TIME;
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) ")");
/* HW functions */
static void bcm63xx_wdt_hw_start(void)
{
bcm_writel(0xfffffffe, bcm63xx_wdt_device.regs + WDT_DEFVAL_REG);
bcm_writel(WDT_START_1, bcm63xx_wdt_device.regs + WDT_CTL_REG);
bcm_writel(WDT_START_2, bcm63xx_wdt_device.regs + WDT_CTL_REG);
}
static void bcm63xx_wdt_hw_stop(void)
{
bcm_writel(WDT_STOP_1, bcm63xx_wdt_device.regs + WDT_CTL_REG);
bcm_writel(WDT_STOP_2, bcm63xx_wdt_device.regs + WDT_CTL_REG);
}
static void bcm63xx_wdt_isr(void *data)
{
struct pt_regs *regs = get_irq_regs();
die(PFX " fire", regs);
}
static void bcm63xx_timer_tick(unsigned long unused)
{
if (!atomic_dec_and_test(&bcm63xx_wdt_device.ticks)) {
bcm63xx_wdt_hw_start();
mod_timer(&bcm63xx_wdt_device.timer, jiffies + HZ);
} else
pr_crit("watchdog will restart system\n");
}
static void bcm63xx_wdt_pet(void)
{
atomic_set(&bcm63xx_wdt_device.ticks, wdt_time);
}
static void bcm63xx_wdt_start(void)
{
bcm63xx_wdt_pet();
bcm63xx_timer_tick(0);
}
static void bcm63xx_wdt_pause(void)
{
del_timer_sync(&bcm63xx_wdt_device.timer);
bcm63xx_wdt_hw_stop();
}
static int bcm63xx_wdt_settimeout(int new_time)
{
if ((new_time <= 0) || (new_time > WDT_MAX_TIME))
return -EINVAL;
wdt_time = new_time;
return 0;
}
static int bcm63xx_wdt_open(struct inode *inode, struct file *file)
{
if (test_and_set_bit(0, &bcm63xx_wdt_device.inuse))
return -EBUSY;
bcm63xx_wdt_start();
return nonseekable_open(inode, file);
}
static int bcm63xx_wdt_release(struct inode *inode, struct file *file)
{
if (expect_close == 42)
bcm63xx_wdt_pause();
else {
pr_crit("Unexpected close, not stopping watchdog!\n");
bcm63xx_wdt_start();
}
clear_bit(0, &bcm63xx_wdt_device.inuse);
expect_close = 0;
return 0;
}
static ssize_t bcm63xx_wdt_write(struct file *file, const char *data,
size_t len, loff_t *ppos)
{
if (len) {
if (!nowayout) {
size_t i;
/* In case it was set long ago */
expect_close = 0;
for (i = 0; i != len; i++) {
char c;
if (get_user(c, data + i))
return -EFAULT;
if (c == 'V')
expect_close = 42;
}
}
bcm63xx_wdt_pet();
}
return len;
}
static struct watchdog_info bcm63xx_wdt_info = {
.identity = PFX,
.options = WDIOF_SETTIMEOUT |
WDIOF_KEEPALIVEPING |
WDIOF_MAGICCLOSE,
};
static long bcm63xx_wdt_ioctl(struct file *file, unsigned int cmd,
unsigned long arg)
{
void __user *argp = (void __user *)arg;
int __user *p = argp;
int new_value, retval = -EINVAL;
switch (cmd) {
case WDIOC_GETSUPPORT:
return copy_to_user(argp, &bcm63xx_wdt_info,
sizeof(bcm63xx_wdt_info)) ? -EFAULT : 0;
case WDIOC_GETSTATUS:
case WDIOC_GETBOOTSTATUS:
return put_user(0, p);
case WDIOC_SETOPTIONS:
if (get_user(new_value, p))
return -EFAULT;
if (new_value & WDIOS_DISABLECARD) {
bcm63xx_wdt_pause();
retval = 0;
}
if (new_value & WDIOS_ENABLECARD) {
bcm63xx_wdt_start();
retval = 0;
}
return retval;
case WDIOC_KEEPALIVE:
bcm63xx_wdt_pet();
return 0;
case WDIOC_SETTIMEOUT:
if (get_user(new_value, p))
return -EFAULT;
if (bcm63xx_wdt_settimeout(new_value))
return -EINVAL;
bcm63xx_wdt_pet();
case WDIOC_GETTIMEOUT:
return put_user(wdt_time, p);
default:
return -ENOTTY;
}
}
static const struct file_operations bcm63xx_wdt_fops = {
.owner = THIS_MODULE,
.llseek = no_llseek,
.write = bcm63xx_wdt_write,
.unlocked_ioctl = bcm63xx_wdt_ioctl,
.open = bcm63xx_wdt_open,
.release = bcm63xx_wdt_release,
};
static struct miscdevice bcm63xx_wdt_miscdev = {
.minor = WATCHDOG_MINOR,
.name = "watchdog",
.fops = &bcm63xx_wdt_fops,
};
static int bcm63xx_wdt_probe(struct platform_device *pdev)
{
int ret;
struct resource *r;
setup_timer(&bcm63xx_wdt_device.timer, bcm63xx_timer_tick, 0L);
r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
if (!r) {
dev_err(&pdev->dev, "failed to get resources\n");
return -ENODEV;
}
bcm63xx_wdt_device.regs = devm_ioremap_nocache(&pdev->dev, r->start,
resource_size(r));
if (!bcm63xx_wdt_device.regs) {
dev_err(&pdev->dev, "failed to remap I/O resources\n");
return -ENXIO;
}
ret = bcm63xx_timer_register(TIMER_WDT_ID, bcm63xx_wdt_isr, NULL);
if (ret < 0) {
dev_err(&pdev->dev, "failed to register wdt timer isr\n");
return ret;
}
if (bcm63xx_wdt_settimeout(wdt_time)) {
bcm63xx_wdt_settimeout(WDT_DEFAULT_TIME);
dev_info(&pdev->dev,
": wdt_time value must be 1 <= wdt_time <= 256, using %d\n",
wdt_time);
}
ret = misc_register(&bcm63xx_wdt_miscdev);
if (ret < 0) {
dev_err(&pdev->dev, "failed to register watchdog device\n");
goto unregister_timer;
}
dev_info(&pdev->dev, " started, timer margin: %d sec\n",
WDT_DEFAULT_TIME);
return 0;
unregister_timer:
bcm63xx_timer_unregister(TIMER_WDT_ID);
return ret;
}
static int bcm63xx_wdt_remove(struct platform_device *pdev)
{
if (!nowayout)
bcm63xx_wdt_pause();
misc_deregister(&bcm63xx_wdt_miscdev);
bcm63xx_timer_unregister(TIMER_WDT_ID);
return 0;
}
static void bcm63xx_wdt_shutdown(struct platform_device *pdev)
{
bcm63xx_wdt_pause();
}
static struct platform_driver bcm63xx_wdt_driver = {
.probe = bcm63xx_wdt_probe,
.remove = bcm63xx_wdt_remove,
.shutdown = bcm63xx_wdt_shutdown,
.driver = {
.owner = THIS_MODULE,
.name = "bcm63xx-wdt",
}
};
module_platform_driver(bcm63xx_wdt_driver);
MODULE_AUTHOR("Miguel Gaio <miguel.gaio@efixo.com>");
MODULE_AUTHOR("Florian Fainelli <florian@openwrt.org>");
MODULE_DESCRIPTION("Driver for the Broadcom BCM63xx SoC watchdog");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:bcm63xx-wdt");