linux/drivers/watchdog/pika_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

302 lines
6.7 KiB
C

/*
* PIKA FPGA based Watchdog Timer
*
* Copyright (c) 2008 PIKA Technologies
* Sean MacLennan <smaclennan@pikatech.com>
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/init.h>
#include <linux/errno.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/fs.h>
#include <linux/miscdevice.h>
#include <linux/watchdog.h>
#include <linux/reboot.h>
#include <linux/jiffies.h>
#include <linux/timer.h>
#include <linux/bitops.h>
#include <linux/uaccess.h>
#include <linux/io.h>
#include <linux/of_address.h>
#include <linux/of_platform.h>
#define DRV_NAME "PIKA-WDT"
/* Hardware timeout in seconds */
#define WDT_HW_TIMEOUT 2
/* Timer heartbeat (500ms) */
#define WDT_TIMEOUT (HZ/2)
/* User land timeout */
#define WDT_HEARTBEAT 15
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 struct {
void __iomem *fpga;
unsigned long next_heartbeat; /* the next_heartbeat for the timer */
unsigned long open;
char expect_close;
int bootstatus;
struct timer_list timer; /* The timer that pings the watchdog */
} pikawdt_private;
static struct watchdog_info ident = {
.identity = DRV_NAME,
.options = WDIOF_CARDRESET |
WDIOF_SETTIMEOUT |
WDIOF_KEEPALIVEPING |
WDIOF_MAGICCLOSE,
};
/*
* Reload the watchdog timer. (ie, pat the watchdog)
*/
static inline void pikawdt_reset(void)
{
/* -- FPGA: Reset Control Register (32bit R/W) (Offset: 0x14) --
* Bit 7, WTCHDG_EN: When set to 1, the watchdog timer is enabled.
* Once enabled, it cannot be disabled. The watchdog can be
* kicked by performing any write access to the reset
* control register (this register).
* Bit 8-11, WTCHDG_TIMEOUT_SEC: Sets the watchdog timeout value in
* seconds. Valid ranges are 1 to 15 seconds. The value can
* be modified dynamically.
*/
unsigned reset = in_be32(pikawdt_private.fpga + 0x14);
/* enable with max timeout - 15 seconds */
reset |= (1 << 7) + (WDT_HW_TIMEOUT << 8);
out_be32(pikawdt_private.fpga + 0x14, reset);
}
/*
* Timer tick
*/
static void pikawdt_ping(unsigned long data)
{
if (time_before(jiffies, pikawdt_private.next_heartbeat) ||
(!nowayout && !pikawdt_private.open)) {
pikawdt_reset();
mod_timer(&pikawdt_private.timer, jiffies + WDT_TIMEOUT);
} else
pr_crit("I will reset your machine !\n");
}
static void pikawdt_keepalive(void)
{
pikawdt_private.next_heartbeat = jiffies + heartbeat * HZ;
}
static void pikawdt_start(void)
{
pikawdt_keepalive();
mod_timer(&pikawdt_private.timer, jiffies + WDT_TIMEOUT);
}
/*
* Watchdog device is opened, and watchdog starts running.
*/
static int pikawdt_open(struct inode *inode, struct file *file)
{
/* /dev/watchdog can only be opened once */
if (test_and_set_bit(0, &pikawdt_private.open))
return -EBUSY;
pikawdt_start();
return nonseekable_open(inode, file);
}
/*
* Close the watchdog device.
*/
static int pikawdt_release(struct inode *inode, struct file *file)
{
/* stop internal ping */
if (!pikawdt_private.expect_close)
del_timer(&pikawdt_private.timer);
clear_bit(0, &pikawdt_private.open);
pikawdt_private.expect_close = 0;
return 0;
}
/*
* Pat the watchdog whenever device is written to.
*/
static ssize_t pikawdt_write(struct file *file, const char __user *data,
size_t len, loff_t *ppos)
{
if (!len)
return 0;
/* Scan for magic character */
if (!nowayout) {
size_t i;
pikawdt_private.expect_close = 0;
for (i = 0; i < len; i++) {
char c;
if (get_user(c, data + i))
return -EFAULT;
if (c == 'V') {
pikawdt_private.expect_close = 42;
break;
}
}
}
pikawdt_keepalive();
return len;
}
/*
* Handle commands from user-space.
*/
static long pikawdt_ioctl(struct file *file,
unsigned int cmd, unsigned long arg)
{
void __user *argp = (void __user *)arg;
int __user *p = argp;
int new_value;
switch (cmd) {
case WDIOC_GETSUPPORT:
return copy_to_user(argp, &ident, sizeof(ident)) ? -EFAULT : 0;
case WDIOC_GETSTATUS:
return put_user(0, p);
case WDIOC_GETBOOTSTATUS:
return put_user(pikawdt_private.bootstatus, p);
case WDIOC_KEEPALIVE:
pikawdt_keepalive();
return 0;
case WDIOC_SETTIMEOUT:
if (get_user(new_value, p))
return -EFAULT;
heartbeat = new_value;
pikawdt_keepalive();
return put_user(new_value, p); /* return current value */
case WDIOC_GETTIMEOUT:
return put_user(heartbeat, p);
}
return -ENOTTY;
}
static const struct file_operations pikawdt_fops = {
.owner = THIS_MODULE,
.llseek = no_llseek,
.open = pikawdt_open,
.release = pikawdt_release,
.write = pikawdt_write,
.unlocked_ioctl = pikawdt_ioctl,
};
static struct miscdevice pikawdt_miscdev = {
.minor = WATCHDOG_MINOR,
.name = "watchdog",
.fops = &pikawdt_fops,
};
static int __init pikawdt_init(void)
{
struct device_node *np;
void __iomem *fpga;
static u32 post1;
int ret;
np = of_find_compatible_node(NULL, NULL, "pika,fpga");
if (np == NULL) {
pr_err("Unable to find fpga\n");
return -ENOENT;
}
pikawdt_private.fpga = of_iomap(np, 0);
of_node_put(np);
if (pikawdt_private.fpga == NULL) {
pr_err("Unable to map fpga\n");
return -ENOMEM;
}
ident.firmware_version = in_be32(pikawdt_private.fpga + 0x1c) & 0xffff;
/* POST information is in the sd area. */
np = of_find_compatible_node(NULL, NULL, "pika,fpga-sd");
if (np == NULL) {
pr_err("Unable to find fpga-sd\n");
ret = -ENOENT;
goto out;
}
fpga = of_iomap(np, 0);
of_node_put(np);
if (fpga == NULL) {
pr_err("Unable to map fpga-sd\n");
ret = -ENOMEM;
goto out;
}
/* -- FPGA: POST Test Results Register 1 (32bit R/W) (Offset: 0x4040) --
* Bit 31, WDOG: Set to 1 when the last reset was caused by a watchdog
* timeout.
*/
post1 = in_be32(fpga + 0x40);
if (post1 & 0x80000000)
pikawdt_private.bootstatus = WDIOF_CARDRESET;
iounmap(fpga);
setup_timer(&pikawdt_private.timer, pikawdt_ping, 0);
ret = misc_register(&pikawdt_miscdev);
if (ret) {
pr_err("Unable to register miscdev\n");
goto out;
}
pr_info("initialized. heartbeat=%d sec (nowayout=%d)\n",
heartbeat, nowayout);
return 0;
out:
iounmap(pikawdt_private.fpga);
return ret;
}
static void __exit pikawdt_exit(void)
{
misc_deregister(&pikawdt_miscdev);
iounmap(pikawdt_private.fpga);
}
module_init(pikawdt_init);
module_exit(pikawdt_exit);
MODULE_AUTHOR("Sean MacLennan <smaclennan@pikatech.com>");
MODULE_DESCRIPTION("PIKA FPGA based Watchdog Timer");
MODULE_LICENSE("GPL");