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kernel-fxtec-pro1x/drivers/char/watchdog/omap_wdt.c
Arjan van de Ven 2b8693c061 [PATCH] mark struct file_operations const 3 
Many struct file_operations in the kernel can be "const".  Marking them const
moves these to the .rodata section, which avoids false sharing with potential
dirty data.  In addition it'll catch accidental writes at compile time to
these shared resources.

Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-02-12 09:48:45 -08:00

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/*
* linux/drivers/char/watchdog/omap_wdt.c
*
* Watchdog driver for the TI OMAP 16xx & 24xx 32KHz (non-secure) watchdog
*
* Author: MontaVista Software, Inc.
* <gdavis@mvista.com> or <source@mvista.com>
*
* 2003 (c) MontaVista Software, Inc. This file is licensed under the
* terms of the GNU General Public License version 2. This program is
* licensed "as is" without any warranty of any kind, whether express
* or implied.
*
* History:
*
* 20030527: George G. Davis <gdavis@mvista.com>
* Initially based on linux-2.4.19-rmk7-pxa1/drivers/char/sa1100_wdt.c
* (c) Copyright 2000 Oleg Drokin <green@crimea.edu>
* Based on SoftDog driver by Alan Cox <alan@redhat.com>
*
* Copyright (c) 2004 Texas Instruments.
* 1. Modified to support OMAP1610 32-KHz watchdog timer
* 2. Ported to 2.6 kernel
*
* Copyright (c) 2005 David Brownell
* Use the driver model and standard identifiers; handle bigger timeouts.
*/
#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/reboot.h>
#include <linux/smp_lock.h>
#include <linux/init.h>
#include <linux/err.h>
#include <linux/platform_device.h>
#include <linux/moduleparam.h>
#include <linux/clk.h>
#include <asm/io.h>
#include <asm/uaccess.h>
#include <asm/hardware.h>
#include <asm/bitops.h>
#include <asm/arch/prcm.h>
#include "omap_wdt.h"
static unsigned timer_margin;
module_param(timer_margin, uint, 0);
MODULE_PARM_DESC(timer_margin, "initial watchdog timeout (in seconds)");
static int omap_wdt_users;
static struct clk *armwdt_ck = NULL;
static struct clk *mpu_wdt_ick = NULL;
static struct clk *mpu_wdt_fck = NULL;
static unsigned int wdt_trgr_pattern = 0x1234;
static void omap_wdt_ping(void)
{
/* wait for posted write to complete */
while ((omap_readl(OMAP_WATCHDOG_WPS)) & 0x08)
cpu_relax();
wdt_trgr_pattern = ~wdt_trgr_pattern;
omap_writel(wdt_trgr_pattern, (OMAP_WATCHDOG_TGR));
/* wait for posted write to complete */
while ((omap_readl(OMAP_WATCHDOG_WPS)) & 0x08)
cpu_relax();
/* reloaded WCRR from WLDR */
}
static void omap_wdt_enable(void)
{
/* Sequence to enable the watchdog */
omap_writel(0xBBBB, OMAP_WATCHDOG_SPR);
while ((omap_readl(OMAP_WATCHDOG_WPS)) & 0x10)
cpu_relax();
omap_writel(0x4444, OMAP_WATCHDOG_SPR);
while ((omap_readl(OMAP_WATCHDOG_WPS)) & 0x10)
cpu_relax();
}
static void omap_wdt_disable(void)
{
/* sequence required to disable watchdog */
omap_writel(0xAAAA, OMAP_WATCHDOG_SPR); /* TIMER_MODE */
while (omap_readl(OMAP_WATCHDOG_WPS) & 0x10)
cpu_relax();
omap_writel(0x5555, OMAP_WATCHDOG_SPR); /* TIMER_MODE */
while (omap_readl(OMAP_WATCHDOG_WPS) & 0x10)
cpu_relax();
}
static void omap_wdt_adjust_timeout(unsigned new_timeout)
{
if (new_timeout < TIMER_MARGIN_MIN)
new_timeout = TIMER_MARGIN_DEFAULT;
if (new_timeout > TIMER_MARGIN_MAX)
new_timeout = TIMER_MARGIN_MAX;
timer_margin = new_timeout;
}
static void omap_wdt_set_timeout(void)
{
u32 pre_margin = GET_WLDR_VAL(timer_margin);
/* just count up at 32 KHz */
while (omap_readl(OMAP_WATCHDOG_WPS) & 0x04)
cpu_relax();
omap_writel(pre_margin, OMAP_WATCHDOG_LDR);
while (omap_readl(OMAP_WATCHDOG_WPS) & 0x04)
cpu_relax();
}
/*
* Allow only one task to hold it open
*/
static int omap_wdt_open(struct inode *inode, struct file *file)
{
if (test_and_set_bit(1, (unsigned long *)&omap_wdt_users))
return -EBUSY;
if (cpu_is_omap16xx())
clk_enable(armwdt_ck); /* Enable the clock */
if (cpu_is_omap24xx()) {
clk_enable(mpu_wdt_ick); /* Enable the interface clock */
clk_enable(mpu_wdt_fck); /* Enable the functional clock */
}
/* initialize prescaler */
while (omap_readl(OMAP_WATCHDOG_WPS) & 0x01)
cpu_relax();
omap_writel((1 << 5) | (PTV << 2), OMAP_WATCHDOG_CNTRL);
while (omap_readl(OMAP_WATCHDOG_WPS) & 0x01)
cpu_relax();
omap_wdt_set_timeout();
omap_wdt_enable();
return 0;
}
static int omap_wdt_release(struct inode *inode, struct file *file)
{
/*
* Shut off the timer unless NOWAYOUT is defined.
*/
#ifndef CONFIG_WATCHDOG_NOWAYOUT
omap_wdt_disable();
if (cpu_is_omap16xx()) {
clk_disable(armwdt_ck); /* Disable the clock */
clk_put(armwdt_ck);
armwdt_ck = NULL;
}
if (cpu_is_omap24xx()) {
clk_disable(mpu_wdt_ick); /* Disable the clock */
clk_disable(mpu_wdt_fck); /* Disable the clock */
clk_put(mpu_wdt_ick);
clk_put(mpu_wdt_fck);
mpu_wdt_ick = NULL;
mpu_wdt_fck = NULL;
}
#else
printk(KERN_CRIT "omap_wdt: Unexpected close, not stopping!\n");
#endif
omap_wdt_users = 0;
return 0;
}
static ssize_t
omap_wdt_write(struct file *file, const char __user *data,
size_t len, loff_t *ppos)
{
/* Refresh LOAD_TIME. */
if (len)
omap_wdt_ping();
return len;
}
static int
omap_wdt_ioctl(struct inode *inode, struct file *file,
unsigned int cmd, unsigned long arg)
{
int new_margin;
static struct watchdog_info ident = {
.identity = "OMAP Watchdog",
.options = WDIOF_SETTIMEOUT,
.firmware_version = 0,
};
switch (cmd) {
default:
return -ENOIOCTLCMD;
case WDIOC_GETSUPPORT:
return copy_to_user((struct watchdog_info __user *)arg, &ident,
sizeof(ident));
case WDIOC_GETSTATUS:
return put_user(0, (int __user *)arg);
case WDIOC_GETBOOTSTATUS:
if (cpu_is_omap16xx())
return put_user(omap_readw(ARM_SYSST),
(int __user *)arg);
if (cpu_is_omap24xx())
return put_user(omap_prcm_get_reset_sources(),
(int __user *)arg);
case WDIOC_KEEPALIVE:
omap_wdt_ping();
return 0;
case WDIOC_SETTIMEOUT:
if (get_user(new_margin, (int __user *)arg))
return -EFAULT;
omap_wdt_adjust_timeout(new_margin);
omap_wdt_disable();
omap_wdt_set_timeout();
omap_wdt_enable();
omap_wdt_ping();
/* Fall */
case WDIOC_GETTIMEOUT:
return put_user(timer_margin, (int __user *)arg);
}
}
static const struct file_operations omap_wdt_fops = {
.owner = THIS_MODULE,
.write = omap_wdt_write,
.ioctl = omap_wdt_ioctl,
.open = omap_wdt_open,
.release = omap_wdt_release,
};
static struct miscdevice omap_wdt_miscdev = {
.minor = WATCHDOG_MINOR,
.name = "watchdog",
.fops = &omap_wdt_fops
};
static int __init omap_wdt_probe(struct platform_device *pdev)
{
struct resource *res, *mem;
int ret;
/* reserve static register mappings */
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
if (!res)
return -ENOENT;
mem = request_mem_region(res->start, res->end - res->start + 1,
pdev->name);
if (mem == NULL)
return -EBUSY;
platform_set_drvdata(pdev, mem);
omap_wdt_users = 0;
if (cpu_is_omap16xx()) {
armwdt_ck = clk_get(&pdev->dev, "armwdt_ck");
if (IS_ERR(armwdt_ck)) {
ret = PTR_ERR(armwdt_ck);
armwdt_ck = NULL;
goto fail;
}
}
if (cpu_is_omap24xx()) {
mpu_wdt_ick = clk_get(&pdev->dev, "mpu_wdt_ick");
if (IS_ERR(mpu_wdt_ick)) {
ret = PTR_ERR(mpu_wdt_ick);
mpu_wdt_ick = NULL;
goto fail;
}
mpu_wdt_fck = clk_get(&pdev->dev, "mpu_wdt_fck");
if (IS_ERR(mpu_wdt_fck)) {
ret = PTR_ERR(mpu_wdt_fck);
mpu_wdt_fck = NULL;
goto fail;
}
}
omap_wdt_disable();
omap_wdt_adjust_timeout(timer_margin);
omap_wdt_miscdev.parent = &pdev->dev;
ret = misc_register(&omap_wdt_miscdev);
if (ret)
goto fail;
pr_info("OMAP Watchdog Timer: initial timeout %d sec\n", timer_margin);
/* autogate OCP interface clock */
omap_writel(0x01, OMAP_WATCHDOG_SYS_CONFIG);
return 0;
fail:
if (armwdt_ck)
clk_put(armwdt_ck);
if (mpu_wdt_ick)
clk_put(mpu_wdt_ick);
if (mpu_wdt_fck)
clk_put(mpu_wdt_fck);
release_resource(mem);
return ret;
}
static void omap_wdt_shutdown(struct platform_device *pdev)
{
omap_wdt_disable();
}
static int omap_wdt_remove(struct platform_device *pdev)
{
struct resource *mem = platform_get_drvdata(pdev);
misc_deregister(&omap_wdt_miscdev);
release_resource(mem);
if (armwdt_ck)
clk_put(armwdt_ck);
if (mpu_wdt_ick)
clk_put(mpu_wdt_ick);
if (mpu_wdt_fck)
clk_put(mpu_wdt_fck);
return 0;
}
#ifdef CONFIG_PM
/* REVISIT ... not clear this is the best way to handle system suspend; and
* it's very inappropriate for selective device suspend (e.g. suspending this
* through sysfs rather than by stopping the watchdog daemon). Also, this
* may not play well enough with NOWAYOUT...
*/
static int omap_wdt_suspend(struct platform_device *pdev, pm_message_t state)
{
if (omap_wdt_users)
omap_wdt_disable();
return 0;
}
static int omap_wdt_resume(struct platform_device *pdev)
{
if (omap_wdt_users) {
omap_wdt_enable();
omap_wdt_ping();
}
return 0;
}
#else
#define omap_wdt_suspend NULL
#define omap_wdt_resume NULL
#endif
static struct platform_driver omap_wdt_driver = {
.probe = omap_wdt_probe,
.remove = omap_wdt_remove,
.shutdown = omap_wdt_shutdown,
.suspend = omap_wdt_suspend,
.resume = omap_wdt_resume,
.driver = {
.owner = THIS_MODULE,
.name = "omap_wdt",
},
};
static int __init omap_wdt_init(void)
{
return platform_driver_register(&omap_wdt_driver);
}
static void __exit omap_wdt_exit(void)
{
platform_driver_unregister(&omap_wdt_driver);
}
module_init(omap_wdt_init);
module_exit(omap_wdt_exit);
MODULE_AUTHOR("George G. Davis");
MODULE_LICENSE("GPL");
MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
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