watchdog: shwdt: Kill off mmap stub and superfluous comments.

The wdt mmaping thing was a special-cased hack that nothing in the wild
depends on, so just kill it off. While at it, sanitize the superfluous
comments in preparation for a driver rewrite and overhauled interface.

Signed-off-by: Paul Mundt <lethal@linux-sh.org>
This commit is contained in:
Paul Mundt 2010-05-24 10:55:59 +09:00
parent 8a37f52052
commit b1fa888e01
2 changed files with 2 additions and 144 deletions

View File

@ -948,14 +948,6 @@ config SH_WDT
To compile this driver as a module, choose M here: the
module will be called shwdt.
config SH_WDT_MMAP
bool "Allow mmap of SH WDT"
default n
depends on SH_WDT
help
If you say Y here, user applications will be able to mmap the
WDT/CPG registers.
# SPARC Architecture
# SPARC64 Architecture

View File

@ -1,9 +1,9 @@
/*
* drivers/char/watchdog/shwdt.c
* drivers/watchdog/shwdt.c
*
* Watchdog driver for integrated watchdog in the SuperH processors.
*
* Copyright (C) 2001, 2002, 2003 Paul Mundt <lethal@linux-sh.org>
* Copyright (C) 2001 - 2010 Paul Mundt <lethal@linux-sh.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
@ -76,14 +76,8 @@ static DEFINE_SPINLOCK(shwdt_lock);
#define WATCHDOG_HEARTBEAT 30 /* 30 sec default heartbeat */
static int heartbeat = WATCHDOG_HEARTBEAT; /* in seconds */
static int nowayout = WATCHDOG_NOWAYOUT;
/**
* sh_wdt_start - Start the Watchdog
*
* Starts the watchdog.
*/
static void sh_wdt_start(void)
{
__u8 csr;
@ -114,15 +108,6 @@ static void sh_wdt_start(void)
sh_wdt_write_csr(csr);
#ifdef CONFIG_CPU_SH2
/*
* Whoever came up with the RSTCSR semantics must've been smoking
* some of the good stuff, since in addition to the WTCSR/WTCNT write
* brain-damage, it's managed to fuck things up one step further..
*
* If we need to clear the WOVF bit, the upper byte has to be 0xa5..
* but if we want to touch RSTE or RSTS, the upper byte has to be
* 0x5a..
*/
csr = sh_wdt_read_rstcsr();
csr &= ~RSTCSR_RSTS;
sh_wdt_write_rstcsr(csr);
@ -130,10 +115,6 @@ static void sh_wdt_start(void)
spin_unlock_irqrestore(&shwdt_lock, flags);
}
/**
* sh_wdt_stop - Stop the Watchdog
* Stops the watchdog.
*/
static void sh_wdt_stop(void)
{
__u8 csr;
@ -149,10 +130,6 @@ static void sh_wdt_stop(void)
spin_unlock_irqrestore(&shwdt_lock, flags);
}
/**
* sh_wdt_keepalive - Keep the Userspace Watchdog Alive
* The Userspace watchdog got a KeepAlive: schedule the next heartbeat.
*/
static inline void sh_wdt_keepalive(void)
{
unsigned long flags;
@ -162,10 +139,6 @@ static inline void sh_wdt_keepalive(void)
spin_unlock_irqrestore(&shwdt_lock, flags);
}
/**
* sh_wdt_set_heartbeat - Set the Userspace Watchdog heartbeat
* Set the Userspace Watchdog heartbeat
*/
static int sh_wdt_set_heartbeat(int t)
{
unsigned long flags;
@ -179,12 +152,6 @@ static int sh_wdt_set_heartbeat(int t)
return 0;
}
/**
* sh_wdt_ping - Ping the Watchdog
* @data: Unused
*
* Clears overflow bit, resets timer counter.
*/
static void sh_wdt_ping(unsigned long data)
{
unsigned long flags;
@ -206,13 +173,6 @@ static void sh_wdt_ping(unsigned long data)
spin_unlock_irqrestore(&shwdt_lock, flags);
}
/**
* sh_wdt_open - Open the Device
* @inode: inode of device
* @file: file handle of device
*
* Watchdog device is opened and started.
*/
static int sh_wdt_open(struct inode *inode, struct file *file)
{
if (test_and_set_bit(0, &shwdt_is_open))
@ -225,13 +185,6 @@ static int sh_wdt_open(struct inode *inode, struct file *file)
return nonseekable_open(inode, file);
}
/**
* sh_wdt_close - Close the Device
* @inode: inode of device
* @file: file handle of device
*
* Watchdog device is closed and stopped.
*/
static int sh_wdt_close(struct inode *inode, struct file *file)
{
if (shwdt_expect_close == 42) {
@ -248,15 +201,6 @@ static int sh_wdt_close(struct inode *inode, struct file *file)
return 0;
}
/**
* sh_wdt_write - Write to Device
* @file: file handle of device
* @buf: buffer to write
* @count: length of buffer
* @ppos: offset
*
* Pings the watchdog on write.
*/
static ssize_t sh_wdt_write(struct file *file, const char *buf,
size_t count, loff_t *ppos)
{
@ -280,64 +224,6 @@ static ssize_t sh_wdt_write(struct file *file, const char *buf,
return count;
}
/**
* sh_wdt_mmap - map WDT/CPG registers into userspace
* @file: file structure for the device
* @vma: VMA to map the registers into
*
* A simple mmap() implementation for the corner cases where the counter
* needs to be mapped in userspace directly. Due to the relatively small
* size of the area, neighbouring registers not necessarily tied to the
* CPG will also be accessible through the register page, so this remains
* configurable for users that really know what they're doing.
*
* Additionaly, the register page maps in the CPG register base relative
* to the nearest page-aligned boundary, which requires that userspace do
* the appropriate CPU subtype math for calculating the page offset for
* the counter value.
*/
static int sh_wdt_mmap(struct file *file, struct vm_area_struct *vma)
{
int ret = -ENOSYS;
#ifdef CONFIG_SH_WDT_MMAP
unsigned long addr;
/* Only support the simple cases where we map in a register page. */
if (((vma->vm_end - vma->vm_start) != PAGE_SIZE) || vma->vm_pgoff)
return -EINVAL;
/*
* Pick WTCNT as the start, it's usually the first register after the
* FRQCR, and neither one are generally page-aligned out of the box.
*/
addr = WTCNT & ~(PAGE_SIZE - 1);
vma->vm_flags |= VM_IO;
vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
if (io_remap_pfn_range(vma, vma->vm_start, addr >> PAGE_SHIFT,
PAGE_SIZE, vma->vm_page_prot)) {
printk(KERN_ERR PFX "%s: io_remap_pfn_range failed\n",
__func__);
return -EAGAIN;
}
ret = 0;
#endif
return ret;
}
/**
* sh_wdt_ioctl - Query Device
* @file: file handle of device
* @cmd: watchdog command
* @arg: argument
*
* Query basic information from the device or ping it, as outlined by the
* watchdog API.
*/
static long sh_wdt_ioctl(struct file *file, unsigned int cmd,
unsigned long arg)
{
@ -386,15 +272,6 @@ static long sh_wdt_ioctl(struct file *file, unsigned int cmd,
return 0;
}
/**
* sh_wdt_notify_sys - Notifier Handler
* @this: notifier block
* @code: notifier event
* @unused: unused
*
* Handles specific events, such as turning off the watchdog during a
* shutdown event.
*/
static int sh_wdt_notify_sys(struct notifier_block *this,
unsigned long code, void *unused)
{
@ -411,7 +288,6 @@ static const struct file_operations sh_wdt_fops = {
.unlocked_ioctl = sh_wdt_ioctl,
.open = sh_wdt_open,
.release = sh_wdt_close,
.mmap = sh_wdt_mmap,
};
static const struct watchdog_info sh_wdt_info = {
@ -431,11 +307,6 @@ static struct miscdevice sh_wdt_miscdev = {
.fops = &sh_wdt_fops,
};
/**
* sh_wdt_init - Initialize module
* Registers the device and notifier handler. Actual device
* initialization is handled by sh_wdt_open().
*/
static int __init sh_wdt_init(void)
{
int rc;
@ -477,11 +348,6 @@ static int __init sh_wdt_init(void)
return 0;
}
/**
* sh_wdt_exit - Deinitialize module
* Unregisters the device and notifier handler. Actual device
* deinitialization is handled by sh_wdt_close().
*/
static void __exit sh_wdt_exit(void)
{
misc_deregister(&sh_wdt_miscdev);