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Commit b1fa888e authored by Paul Mundt's avatar Paul Mundt
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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: default avatarPaul Mundt <lethal@linux-sh.org>
parent 8a37f520
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+0 −8
Original line number Diff line number Diff line
@@ -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
+2 −136
Original line number Diff line number Diff line
/*
 * 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);