kernel_optimize_test/drivers/watchdog/i6300esb.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

500 lines
12 KiB
C

/*
* i6300esb: Watchdog timer driver for Intel 6300ESB chipset
*
* (c) Copyright 2004 Google Inc.
* (c) Copyright 2005 David Härdeman <david@2gen.com>
*
* 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.
*
* based on i810-tco.c which is in turn based on softdog.c
*
* The timer is implemented in the following I/O controller hubs:
* (See the intel documentation on http://developer.intel.com.)
* 6300ESB chip : document number 300641-004
*
* 2004YYZZ Ross Biro
* Initial version 0.01
* 2004YYZZ Ross Biro
* Version 0.02
* 20050210 David Härdeman <david@2gen.com>
* Ported driver to kernel 2.6
*/
/*
* Includes, defines, variables, module parameters, ...
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/module.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/fs.h>
#include <linux/mm.h>
#include <linux/miscdevice.h>
#include <linux/watchdog.h>
#include <linux/init.h>
#include <linux/pci.h>
#include <linux/ioport.h>
#include <linux/uaccess.h>
#include <linux/io.h>
/* Module and version information */
#define ESB_VERSION "0.05"
#define ESB_MODULE_NAME "i6300ESB timer"
#define ESB_DRIVER_NAME ESB_MODULE_NAME ", v" ESB_VERSION
/* PCI configuration registers */
#define ESB_CONFIG_REG 0x60 /* Config register */
#define ESB_LOCK_REG 0x68 /* WDT lock register */
/* Memory mapped registers */
#define ESB_TIMER1_REG (BASEADDR + 0x00)/* Timer1 value after each reset */
#define ESB_TIMER2_REG (BASEADDR + 0x04)/* Timer2 value after each reset */
#define ESB_GINTSR_REG (BASEADDR + 0x08)/* General Interrupt Status Register */
#define ESB_RELOAD_REG (BASEADDR + 0x0c)/* Reload register */
/* Lock register bits */
#define ESB_WDT_FUNC (0x01 << 2) /* Watchdog functionality */
#define ESB_WDT_ENABLE (0x01 << 1) /* Enable WDT */
#define ESB_WDT_LOCK (0x01 << 0) /* Lock (nowayout) */
/* Config register bits */
#define ESB_WDT_REBOOT (0x01 << 5) /* Enable reboot on timeout */
#define ESB_WDT_FREQ (0x01 << 2) /* Decrement frequency */
#define ESB_WDT_INTTYPE (0x03 << 0) /* Interrupt type on timer1 timeout */
/* Reload register bits */
#define ESB_WDT_TIMEOUT (0x01 << 9) /* Watchdog timed out */
#define ESB_WDT_RELOAD (0x01 << 8) /* prevent timeout */
/* Magic constants */
#define ESB_UNLOCK1 0x80 /* Step 1 to unlock reset registers */
#define ESB_UNLOCK2 0x86 /* Step 2 to unlock reset registers */
/* internal variables */
static void __iomem *BASEADDR;
static DEFINE_SPINLOCK(esb_lock); /* Guards the hardware */
static unsigned long timer_alive;
static struct pci_dev *esb_pci;
static unsigned short triggered; /* The status of the watchdog upon boot */
static char esb_expect_close;
/* We can only use 1 card due to the /dev/watchdog restriction */
static int cards_found;
/* module parameters */
/* 30 sec default heartbeat (1 < heartbeat < 2*1023) */
#define WATCHDOG_HEARTBEAT 30
static int heartbeat = WATCHDOG_HEARTBEAT; /* in seconds */
module_param(heartbeat, int, 0);
MODULE_PARM_DESC(heartbeat,
"Watchdog heartbeat in seconds. (1<heartbeat<2046, default="
__MODULE_STRING(WATCHDOG_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) ")");
/*
* Some i6300ESB specific functions
*/
/*
* Prepare for reloading the timer by unlocking the proper registers.
* This is performed by first writing 0x80 followed by 0x86 to the
* reload register. After this the appropriate registers can be written
* to once before they need to be unlocked again.
*/
static inline void esb_unlock_registers(void)
{
writew(ESB_UNLOCK1, ESB_RELOAD_REG);
writew(ESB_UNLOCK2, ESB_RELOAD_REG);
}
static int esb_timer_start(void)
{
u8 val;
spin_lock(&esb_lock);
esb_unlock_registers();
writew(ESB_WDT_RELOAD, ESB_RELOAD_REG);
/* Enable or Enable + Lock? */
val = ESB_WDT_ENABLE | (nowayout ? ESB_WDT_LOCK : 0x00);
pci_write_config_byte(esb_pci, ESB_LOCK_REG, val);
spin_unlock(&esb_lock);
return 0;
}
static int esb_timer_stop(void)
{
u8 val;
spin_lock(&esb_lock);
/* First, reset timers as suggested by the docs */
esb_unlock_registers();
writew(ESB_WDT_RELOAD, ESB_RELOAD_REG);
/* Then disable the WDT */
pci_write_config_byte(esb_pci, ESB_LOCK_REG, 0x0);
pci_read_config_byte(esb_pci, ESB_LOCK_REG, &val);
spin_unlock(&esb_lock);
/* Returns 0 if the timer was disabled, non-zero otherwise */
return val & ESB_WDT_ENABLE;
}
static void esb_timer_keepalive(void)
{
spin_lock(&esb_lock);
esb_unlock_registers();
writew(ESB_WDT_RELOAD, ESB_RELOAD_REG);
/* FIXME: Do we need to flush anything here? */
spin_unlock(&esb_lock);
}
static int esb_timer_set_heartbeat(int time)
{
u32 val;
if (time < 0x1 || time > (2 * 0x03ff))
return -EINVAL;
spin_lock(&esb_lock);
/* We shift by 9, so if we are passed a value of 1 sec,
* val will be 1 << 9 = 512, then write that to two
* timers => 2 * 512 = 1024 (which is decremented at 1KHz)
*/
val = time << 9;
/* Write timer 1 */
esb_unlock_registers();
writel(val, ESB_TIMER1_REG);
/* Write timer 2 */
esb_unlock_registers();
writel(val, ESB_TIMER2_REG);
/* Reload */
esb_unlock_registers();
writew(ESB_WDT_RELOAD, ESB_RELOAD_REG);
/* FIXME: Do we need to flush everything out? */
/* Done */
heartbeat = time;
spin_unlock(&esb_lock);
return 0;
}
/*
* /dev/watchdog handling
*/
static int esb_open(struct inode *inode, struct file *file)
{
/* /dev/watchdog can only be opened once */
if (test_and_set_bit(0, &timer_alive))
return -EBUSY;
/* Reload and activate timer */
esb_timer_start();
return nonseekable_open(inode, file);
}
static int esb_release(struct inode *inode, struct file *file)
{
/* Shut off the timer. */
if (esb_expect_close == 42)
esb_timer_stop();
else {
pr_crit("Unexpected close, not stopping watchdog!\n");
esb_timer_keepalive();
}
clear_bit(0, &timer_alive);
esb_expect_close = 0;
return 0;
}
static ssize_t esb_write(struct file *file, const char __user *data,
size_t len, loff_t *ppos)
{
/* See if we got the magic character 'V' and reload the timer */
if (len) {
if (!nowayout) {
size_t i;
/* note: just in case someone wrote the magic character
* five months ago... */
esb_expect_close = 0;
/* scan to see whether or not we got the
* magic character */
for (i = 0; i != len; i++) {
char c;
if (get_user(c, data + i))
return -EFAULT;
if (c == 'V')
esb_expect_close = 42;
}
}
/* someone wrote to us, we should reload the timer */
esb_timer_keepalive();
}
return len;
}
static long esb_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{
int new_options, retval = -EINVAL;
int new_heartbeat;
void __user *argp = (void __user *)arg;
int __user *p = argp;
static const struct watchdog_info ident = {
.options = WDIOF_SETTIMEOUT |
WDIOF_KEEPALIVEPING |
WDIOF_MAGICCLOSE,
.firmware_version = 0,
.identity = ESB_MODULE_NAME,
};
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(triggered, p);
case WDIOC_SETOPTIONS:
{
if (get_user(new_options, p))
return -EFAULT;
if (new_options & WDIOS_DISABLECARD) {
esb_timer_stop();
retval = 0;
}
if (new_options & WDIOS_ENABLECARD) {
esb_timer_start();
retval = 0;
}
return retval;
}
case WDIOC_KEEPALIVE:
esb_timer_keepalive();
return 0;
case WDIOC_SETTIMEOUT:
{
if (get_user(new_heartbeat, p))
return -EFAULT;
if (esb_timer_set_heartbeat(new_heartbeat))
return -EINVAL;
esb_timer_keepalive();
/* Fall */
}
case WDIOC_GETTIMEOUT:
return put_user(heartbeat, p);
default:
return -ENOTTY;
}
}
/*
* Kernel Interfaces
*/
static const struct file_operations esb_fops = {
.owner = THIS_MODULE,
.llseek = no_llseek,
.write = esb_write,
.unlocked_ioctl = esb_ioctl,
.open = esb_open,
.release = esb_release,
};
static struct miscdevice esb_miscdev = {
.minor = WATCHDOG_MINOR,
.name = "watchdog",
.fops = &esb_fops,
};
/*
* Data for PCI driver interface
*/
static DEFINE_PCI_DEVICE_TABLE(esb_pci_tbl) = {
{ PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_ESB_9), },
{ 0, }, /* End of list */
};
MODULE_DEVICE_TABLE(pci, esb_pci_tbl);
/*
* Init & exit routines
*/
static unsigned char esb_getdevice(struct pci_dev *pdev)
{
if (pci_enable_device(pdev)) {
pr_err("failed to enable device\n");
goto err_devput;
}
if (pci_request_region(pdev, 0, ESB_MODULE_NAME)) {
pr_err("failed to request region\n");
goto err_disable;
}
BASEADDR = pci_ioremap_bar(pdev, 0);
if (BASEADDR == NULL) {
/* Something's wrong here, BASEADDR has to be set */
pr_err("failed to get BASEADDR\n");
goto err_release;
}
/* Done */
esb_pci = pdev;
return 1;
err_release:
pci_release_region(pdev, 0);
err_disable:
pci_disable_device(pdev);
err_devput:
return 0;
}
static void esb_initdevice(void)
{
u8 val1;
u16 val2;
/*
* Config register:
* Bit 5 : 0 = Enable WDT_OUTPUT
* Bit 2 : 0 = set the timer frequency to the PCI clock
* divided by 2^15 (approx 1KHz).
* Bits 1:0 : 11 = WDT_INT_TYPE Disabled.
* The watchdog has two timers, it can be setup so that the
* expiry of timer1 results in an interrupt and the expiry of
* timer2 results in a reboot. We set it to not generate
* any interrupts as there is not much we can do with it
* right now.
*/
pci_write_config_word(esb_pci, ESB_CONFIG_REG, 0x0003);
/* Check that the WDT isn't already locked */
pci_read_config_byte(esb_pci, ESB_LOCK_REG, &val1);
if (val1 & ESB_WDT_LOCK)
pr_warn("nowayout already set\n");
/* Set the timer to watchdog mode and disable it for now */
pci_write_config_byte(esb_pci, ESB_LOCK_REG, 0x00);
/* Check if the watchdog was previously triggered */
esb_unlock_registers();
val2 = readw(ESB_RELOAD_REG);
if (val2 & ESB_WDT_TIMEOUT)
triggered = WDIOF_CARDRESET;
/* Reset WDT_TIMEOUT flag and timers */
esb_unlock_registers();
writew((ESB_WDT_TIMEOUT | ESB_WDT_RELOAD), ESB_RELOAD_REG);
/* And set the correct timeout value */
esb_timer_set_heartbeat(heartbeat);
}
static int esb_probe(struct pci_dev *pdev,
const struct pci_device_id *ent)
{
int ret;
cards_found++;
if (cards_found == 1)
pr_info("Intel 6300ESB WatchDog Timer Driver v%s\n",
ESB_VERSION);
if (cards_found > 1) {
pr_err("This driver only supports 1 device\n");
return -ENODEV;
}
/* Check whether or not the hardware watchdog is there */
if (!esb_getdevice(pdev) || esb_pci == NULL)
return -ENODEV;
/* Check that the heartbeat value is within it's range;
if not reset to the default */
if (heartbeat < 0x1 || heartbeat > 2 * 0x03ff) {
heartbeat = WATCHDOG_HEARTBEAT;
pr_info("heartbeat value must be 1<heartbeat<2046, using %d\n",
heartbeat);
}
/* Initialize the watchdog and make sure it does not run */
esb_initdevice();
/* Register the watchdog so that userspace has access to it */
ret = misc_register(&esb_miscdev);
if (ret != 0) {
pr_err("cannot register miscdev on minor=%d (err=%d)\n",
WATCHDOG_MINOR, ret);
goto err_unmap;
}
pr_info("initialized (0x%p). heartbeat=%d sec (nowayout=%d)\n",
BASEADDR, heartbeat, nowayout);
return 0;
err_unmap:
iounmap(BASEADDR);
pci_release_region(esb_pci, 0);
pci_disable_device(esb_pci);
esb_pci = NULL;
return ret;
}
static void esb_remove(struct pci_dev *pdev)
{
/* Stop the timer before we leave */
if (!nowayout)
esb_timer_stop();
/* Deregister */
misc_deregister(&esb_miscdev);
iounmap(BASEADDR);
pci_release_region(esb_pci, 0);
pci_disable_device(esb_pci);
esb_pci = NULL;
}
static void esb_shutdown(struct pci_dev *pdev)
{
esb_timer_stop();
}
static struct pci_driver esb_driver = {
.name = ESB_MODULE_NAME,
.id_table = esb_pci_tbl,
.probe = esb_probe,
.remove = esb_remove,
.shutdown = esb_shutdown,
};
module_pci_driver(esb_driver);
MODULE_AUTHOR("Ross Biro and David Härdeman");
MODULE_DESCRIPTION("Watchdog driver for Intel 6300ESB chipsets");
MODULE_LICENSE("GPL");