linux/drivers/watchdog/rc32434_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

331 lines
8.1 KiB
C

/*
* IDT Interprise 79RC32434 watchdog driver
*
* Copyright (C) 2006, Ondrej Zajicek <santiago@crfreenet.org>
* Copyright (C) 2008, Florian Fainelli <florian@openwrt.org>
*
* based on
* SoftDog 0.05: A Software Watchdog Device
*
* (c) Copyright 1996 Alan Cox <alan@lxorguk.ukuu.org.uk>,
* All Rights Reserved.
*
* 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/module.h> /* For module specific items */
#include <linux/moduleparam.h> /* For new moduleparam's */
#include <linux/types.h> /* For standard types (like size_t) */
#include <linux/errno.h> /* For the -ENODEV/... values */
#include <linux/kernel.h> /* For printk/panic/... */
#include <linux/fs.h> /* For file operations */
#include <linux/miscdevice.h> /* For struct miscdevice */
#include <linux/watchdog.h> /* For the watchdog specific items */
#include <linux/init.h> /* For __init/__exit/... */
#include <linux/platform_device.h> /* For platform_driver framework */
#include <linux/spinlock.h> /* For spin_lock/spin_unlock/... */
#include <linux/uaccess.h> /* For copy_to_user/put_user/... */
#include <linux/io.h> /* For devm_ioremap_nocache */
#include <asm/mach-rc32434/integ.h> /* For the Watchdog registers */
#define VERSION "1.0"
static struct {
unsigned long inuse;
spinlock_t io_lock;
} rc32434_wdt_device;
static struct integ __iomem *wdt_reg;
static int expect_close;
/* Board internal clock speed in Hz,
* the watchdog timer ticks at. */
extern unsigned int idt_cpu_freq;
/* translate wtcompare value to seconds and vice versa */
#define WTCOMP2SEC(x) (x / idt_cpu_freq)
#define SEC2WTCOMP(x) (x * idt_cpu_freq)
/* Use a default timeout of 20s. This should be
* safe for CPU clock speeds up to 400MHz, as
* ((2 ^ 32) - 1) / (400MHz / 2) = 21s. */
#define WATCHDOG_TIMEOUT 20
static int timeout = WATCHDOG_TIMEOUT;
module_param(timeout, int, 0);
MODULE_PARM_DESC(timeout, "Watchdog timeout value, in seconds (default="
__MODULE_STRING(WATCHDOG_TIMEOUT) ")");
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) ")");
/* apply or and nand masks to data read from addr and write back */
#define SET_BITS(addr, or, nand) \
writel((readl(&addr) | or) & ~nand, &addr)
static int rc32434_wdt_set(int new_timeout)
{
int max_to = WTCOMP2SEC((u32)-1);
if (new_timeout < 0 || new_timeout > max_to) {
pr_err("timeout value must be between 0 and %d\n", max_to);
return -EINVAL;
}
timeout = new_timeout;
spin_lock(&rc32434_wdt_device.io_lock);
writel(SEC2WTCOMP(timeout), &wdt_reg->wtcompare);
spin_unlock(&rc32434_wdt_device.io_lock);
return 0;
}
static void rc32434_wdt_start(void)
{
u32 or, nand;
spin_lock(&rc32434_wdt_device.io_lock);
/* zero the counter before enabling */
writel(0, &wdt_reg->wtcount);
/* don't generate a non-maskable interrupt,
* do a warm reset instead */
nand = 1 << RC32434_ERR_WNE;
or = 1 << RC32434_ERR_WRE;
/* reset the ERRCS timeout bit in case it's set */
nand |= 1 << RC32434_ERR_WTO;
SET_BITS(wdt_reg->errcs, or, nand);
/* set the timeout (either default or based on module param) */
rc32434_wdt_set(timeout);
/* reset WTC timeout bit and enable WDT */
nand = 1 << RC32434_WTC_TO;
or = 1 << RC32434_WTC_EN;
SET_BITS(wdt_reg->wtc, or, nand);
spin_unlock(&rc32434_wdt_device.io_lock);
pr_info("Started watchdog timer\n");
}
static void rc32434_wdt_stop(void)
{
spin_lock(&rc32434_wdt_device.io_lock);
/* Disable WDT */
SET_BITS(wdt_reg->wtc, 0, 1 << RC32434_WTC_EN);
spin_unlock(&rc32434_wdt_device.io_lock);
pr_info("Stopped watchdog timer\n");
}
static void rc32434_wdt_ping(void)
{
spin_lock(&rc32434_wdt_device.io_lock);
writel(0, &wdt_reg->wtcount);
spin_unlock(&rc32434_wdt_device.io_lock);
}
static int rc32434_wdt_open(struct inode *inode, struct file *file)
{
if (test_and_set_bit(0, &rc32434_wdt_device.inuse))
return -EBUSY;
if (nowayout)
__module_get(THIS_MODULE);
rc32434_wdt_start();
rc32434_wdt_ping();
return nonseekable_open(inode, file);
}
static int rc32434_wdt_release(struct inode *inode, struct file *file)
{
if (expect_close == 42) {
rc32434_wdt_stop();
module_put(THIS_MODULE);
} else {
pr_crit("device closed unexpectedly. WDT will not stop!\n");
rc32434_wdt_ping();
}
clear_bit(0, &rc32434_wdt_device.inuse);
return 0;
}
static ssize_t rc32434_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;
}
}
rc32434_wdt_ping();
return len;
}
return 0;
}
static long rc32434_wdt_ioctl(struct file *file, unsigned int cmd,
unsigned long arg)
{
void __user *argp = (void __user *)arg;
int new_timeout;
unsigned int value;
static const struct watchdog_info ident = {
.options = WDIOF_SETTIMEOUT |
WDIOF_KEEPALIVEPING |
WDIOF_MAGICCLOSE,
.identity = "RC32434_WDT Watchdog",
};
switch (cmd) {
case WDIOC_GETSUPPORT:
if (copy_to_user(argp, &ident, sizeof(ident)))
return -EFAULT;
break;
case WDIOC_GETSTATUS:
case WDIOC_GETBOOTSTATUS:
value = 0;
if (copy_to_user(argp, &value, sizeof(int)))
return -EFAULT;
break;
case WDIOC_SETOPTIONS:
if (copy_from_user(&value, argp, sizeof(int)))
return -EFAULT;
switch (value) {
case WDIOS_ENABLECARD:
rc32434_wdt_start();
break;
case WDIOS_DISABLECARD:
rc32434_wdt_stop();
break;
default:
return -EINVAL;
}
break;
case WDIOC_KEEPALIVE:
rc32434_wdt_ping();
break;
case WDIOC_SETTIMEOUT:
if (copy_from_user(&new_timeout, argp, sizeof(int)))
return -EFAULT;
if (rc32434_wdt_set(new_timeout))
return -EINVAL;
/* Fall through */
case WDIOC_GETTIMEOUT:
return copy_to_user(argp, &timeout, sizeof(int));
default:
return -ENOTTY;
}
return 0;
}
static const struct file_operations rc32434_wdt_fops = {
.owner = THIS_MODULE,
.llseek = no_llseek,
.write = rc32434_wdt_write,
.unlocked_ioctl = rc32434_wdt_ioctl,
.open = rc32434_wdt_open,
.release = rc32434_wdt_release,
};
static struct miscdevice rc32434_wdt_miscdev = {
.minor = WATCHDOG_MINOR,
.name = "watchdog",
.fops = &rc32434_wdt_fops,
};
static int rc32434_wdt_probe(struct platform_device *pdev)
{
int ret;
struct resource *r;
r = platform_get_resource_byname(pdev, IORESOURCE_MEM, "rb532_wdt_res");
if (!r) {
pr_err("failed to retrieve resources\n");
return -ENODEV;
}
wdt_reg = devm_ioremap_nocache(&pdev->dev, r->start, resource_size(r));
if (!wdt_reg) {
pr_err("failed to remap I/O resources\n");
return -ENXIO;
}
spin_lock_init(&rc32434_wdt_device.io_lock);
/* Make sure the watchdog is not running */
rc32434_wdt_stop();
/* Check that the heartbeat value is within it's range;
* if not reset to the default */
if (rc32434_wdt_set(timeout)) {
rc32434_wdt_set(WATCHDOG_TIMEOUT);
pr_info("timeout value must be between 0 and %d\n",
WTCOMP2SEC((u32)-1));
}
ret = misc_register(&rc32434_wdt_miscdev);
if (ret < 0) {
pr_err("failed to register watchdog device\n");
return ret;
}
pr_info("Watchdog Timer version " VERSION ", timer margin: %d sec\n",
timeout);
return 0;
}
static int rc32434_wdt_remove(struct platform_device *pdev)
{
misc_deregister(&rc32434_wdt_miscdev);
return 0;
}
static void rc32434_wdt_shutdown(struct platform_device *pdev)
{
rc32434_wdt_stop();
}
static struct platform_driver rc32434_wdt_driver = {
.probe = rc32434_wdt_probe,
.remove = rc32434_wdt_remove,
.shutdown = rc32434_wdt_shutdown,
.driver = {
.name = "rc32434_wdt",
}
};
module_platform_driver(rc32434_wdt_driver);
MODULE_AUTHOR("Ondrej Zajicek <santiago@crfreenet.org>,"
"Florian Fainelli <florian@openwrt.org>");
MODULE_DESCRIPTION("Driver for the IDT RC32434 SoC watchdog");
MODULE_LICENSE("GPL");