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SubjectRe: [PATCH] Added MIPS RM9K watchdog driver
Hi All,

Can you all review the following watchdog driver? I want to include
it in my linux-2.6-watchdog-mm tree, but would appreciate it if you
could have all a look at it again.

Thomas: I moved start and stop code into seperate functions. I also
deleted the #include <rm9k_wdt.h> because the file doesn't exist.
Note that the shutdown function of the platform_device_driver is
similar to a reboot notifier.

Thanks in advance,
Wim.

--------------------------------------------------------------------------------
/*
* Watchdog implementation for GPI h/w found on PMC-Sierra RM9xxx
* chips.
*
* Copyright (C) 2004 by Basler Vision Technologies AG
* Author: Thomas Koeller <thomas.koeller@baslerweb.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.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include <linux/platform_device.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/interrupt.h>
#include <linux/fs.h>
#include <linux/reboot.h>
#include <linux/notifier.h>
#include <linux/miscdevice.h>
#include <linux/watchdog.h>
#include <asm/io.h>
#include <asm/atomic.h>
#include <asm/processor.h>
#include <asm/uaccess.h>
#include <asm/system.h>
#include <asm/rm9k-ocd.h>


#define CLOCK 125000000
#define MAX_TIMEOUT_SECONDS 32
#define CPCCR 0x0080
#define CPGIG1SR 0x0044
#define CPGIG1ER 0x0054


/* Function prototypes */
static int __init wdt_gpi_probe(struct device *);
static int __exit wdt_gpi_remove(struct device *);
static void wdt_gpi_start(void);
static void wdt_gpi_stop(void);
static void wdt_gpi_set_timeout(unsigned int);
static int wdt_gpi_open(struct inode *, struct file *);
static int wdt_gpi_release(struct inode *, struct file *);
static ssize_t wdt_gpi_write(struct file *, const char __user *, size_t, loff_t *);
static long wdt_gpi_ioctl(struct file *, unsigned int, unsigned long);
static const struct resource *wdt_gpi_get_resource(struct platform_device *, const char *, unsigned int);
static int wdt_gpi_notify(struct notifier_block *, unsigned long, void *);
static irqreturn_t wdt_gpi_irqhdl(int, void *, struct pt_regs *);



static const char wdt_gpi_name[] = "wdt_gpi";
static atomic_t opencnt;
static int expect_close;
static int locked = 0;



/* These are set from device resources */
static void __iomem * wd_regs;
static unsigned int wd_irq, wd_ctr;


/* Module arguments */
static int timeout = MAX_TIMEOUT_SECONDS;
module_param(timeout, int, 0444);
static unsigned long resetaddr = 0xbffdc200;
module_param(resetaddr, ulong, 0444);
static unsigned long flagaddr = 0xbffdc104;
module_param(flagaddr, ulong, 0444);
static int powercycle = 0;
module_param(powercycle, bool, 0444);
static int nowayout = WATCHDOG_NOWAYOUT;
module_param(nowayout, bool, 0444);



static struct file_operations fops = {
.owner = THIS_MODULE,
.open = wdt_gpi_open,
.release = wdt_gpi_release,
.write = wdt_gpi_write,
.unlocked_ioctl = wdt_gpi_ioctl,
};
static struct miscdevice miscdev = {
.minor = WATCHDOG_MINOR,
.name = wdt_gpi_name,
.fops = &fops,
};
static struct device_driver wdt_gpi_driver = {
.name = (char *) wdt_gpi_name,
.bus = &platform_bus_type,
.owner = THIS_MODULE,
.probe = wdt_gpi_probe,
.remove = __exit_p(wdt_gpi_remove),
.shutdown = NULL,
.suspend = NULL,
.resume = NULL,
};
static struct notifier_block wdt_gpi_shutdown = {
.notifier_call = wdt_gpi_notify,
};


static const struct resource *
wdt_gpi_get_resource(struct platform_device *pdv, const char *name,
unsigned int type)
{
char buf[80];
if (snprintf(buf, sizeof buf, "%s_0", name) >= sizeof buf)
return NULL;
return platform_get_resource_byname(pdv, type, buf);
}


/* No hotplugging on the platform bus - use __init */
static int __init wdt_gpi_probe(struct device *dev)
{
int res;
struct platform_device * const pdv = to_platform_device(dev);
const struct resource
* const rr = wdt_gpi_get_resource(pdv, WDT_RESOURCE_REGS,
IORESOURCE_MEM),
* const ri = wdt_gpi_get_resource(pdv, WDT_RESOURCE_IRQ,
IORESOURCE_IRQ),
* const rc = wdt_gpi_get_resource(pdv, WDT_RESOURCE_COUNTER,
0);
if (unlikely(!rr || !ri || !rc))
return -ENXIO;
wd_regs = ioremap_nocache(rr->start, rr->end + 1 - rr->start);
if (unlikely(!wd_regs))
return -ENOMEM;
wd_irq = ri->start;
wd_ctr = rc->start;
res = misc_register(&miscdev);
if (res)
iounmap(wd_regs);
else
register_reboot_notifier(&wdt_gpi_shutdown);
return res;
}


static int __exit wdt_gpi_remove(struct device *dev)
{
int res;
unregister_reboot_notifier(&wdt_gpi_shutdown);
res = misc_deregister(&miscdev);
iounmap(wd_regs);
wd_regs = NULL;
return res;
}

static void wdt_gpi_start(void)
{
u32 reg;
lock_titan_regs();
reg = titan_readl(CPGIG1ER);
titan_writel(reg | (0x100 << wd_ctr), CPGIG1ER);
iob();
unlock_titan_regs();
}
static void wdt_gpi_stop(void)
{
u32 reg;
lock_titan_regs();
reg = titan_readl(CPCCR) & ~(0xf << (wd_ctr * 4));
titan_writel(reg, CPCCR);
reg = titan_readl(CPGIG1ER);
titan_writel(reg & ~(0x100 << wd_ctr), CPGIG1ER);
iob();
unlock_titan_regs();
}
static void wdt_gpi_set_timeout(unsigned int to)
{
u32 reg;
const u32 wdval = (to * CLOCK) & ~0x0000000f;
lock_titan_regs();
reg = titan_readl(CPCCR) & ~(0xf << (wd_ctr * 4));
titan_writel(reg, CPCCR);
wmb();
__raw_writel(wdval, wd_regs + 0x0000);
wmb();
titan_writel(reg | (0x2 << (wd_ctr * 4)), CPCCR);
wmb();
titan_writel(reg | (0x5 << (wd_ctr * 4)), CPCCR);
iob();
unlock_titan_regs();
}


static int wdt_gpi_open(struct inode *inode, struct file *file)
{
int res;
if (unlikely(0 > atomic_dec_if_positive(&opencnt)))
return -EBUSY;
expect_close = 0;
if (locked) {
module_put(THIS_MODULE);
free_irq(wd_irq, &miscdev);
locked = 0;
}
res = request_irq(wd_irq, wdt_gpi_irqhdl, SA_SHIRQ | SA_INTERRUPT,
wdt_gpi_name, &miscdev);
if (unlikely(res))
return res;
wdt_gpi_set_timeout(timeout);
wdt_gpi_start();

printk(KERN_INFO "%s: watchdog started, timeout = %u seconds\n",
wdt_gpi_name, timeout);
return nonseekable_open(inode, file);
}


static int wdt_gpi_release(struct inode *i, struct file *f)
{
if (nowayout) {
printk(KERN_NOTICE "%s: no way out - watchdog left running\n",
wdt_gpi_name);
__module_get(THIS_MODULE);
locked = 1;
} else {
if (expect_close) {
wdt_gpi_stop();
free_irq(wd_irq, &miscdev);
printk(KERN_INFO "%s: watchdog stopped\n", wdt_gpi_name);
} else {
printk(KERN_NOTICE "%s: unexpected close() -"
" watchdog left running\n",
wdt_gpi_name);
wdt_gpi_set_timeout(timeout);
__module_get(THIS_MODULE);
locked = 1;
}
}
atomic_inc(&opencnt);
return 0;
}


static ssize_t
wdt_gpi_write(struct file *f, const char __user *d, size_t s, loff_t *o)
{
char val;
wdt_gpi_set_timeout(timeout);
expect_close = (s > 0) && !get_user(val, d) && (val == 'V');
return s ? 1 : 0;
}


static long
wdt_gpi_ioctl(struct file *f, unsigned int cmd, unsigned long arg)
{
long res = -ENOTTY;
const long size = _IOC_SIZE(cmd);
int stat;
static struct watchdog_info wdinfo = {
.identity = "RM9xxx/GPI watchdog",
.firmware_version = 0,
.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING
};
if (unlikely(_IOC_TYPE(cmd) != WATCHDOG_IOCTL_BASE))
return -ENOTTY;
if ((_IOC_DIR(cmd) & _IOC_READ)
&& !access_ok(VERIFY_WRITE, arg, size))
return -EFAULT;
if ((_IOC_DIR(cmd) & _IOC_WRITE)
&& !access_ok(VERIFY_READ, arg, size))
return -EFAULT;
expect_close = 0;

switch (cmd) {
case WDIOC_GETSUPPORT:
wdinfo.options = nowayout ?
WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING :
WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE;
res = __copy_to_user((void __user *)arg, &wdinfo, size) ?
-EFAULT : size;
break;
case WDIOC_GETSTATUS:
break;

case WDIOC_GETBOOTSTATUS:
stat = (*(volatile char *) flagaddr & 0x01)
? WDIOF_CARDRESET : 0;
res = __copy_to_user((void __user *)arg, &stat, size) ?
-EFAULT : size;
break;

case WDIOC_SETOPTIONS:
break;

case WDIOC_KEEPALIVE:
wdt_gpi_set_timeout(timeout);
res = size;
break;

case WDIOC_SETTIMEOUT:
{
int val;
if (unlikely(__copy_from_user(&val, (const void __user *) arg,
size))) {
res = -EFAULT;
break;
}
if (val > 32)
val = 32;
timeout = val;
wdt_gpi_set_timeout(val);
res = size;
printk("%s: timeout set to %u seconds\n",
wdt_gpi_name, timeout);
}
break;
case WDIOC_GETTIMEOUT:
res = __copy_to_user((void __user *) arg, &timeout, size) ?
-EFAULT : size;
break;
}
return res;
}



static irqreturn_t wdt_gpi_irqhdl(int irq, void *ctxt, struct pt_regs *regs)
{
if (!unlikely(__raw_readl(wd_regs + 0x0008) & 0x1))
return IRQ_NONE;
__raw_writel(0x1, wd_regs + 0x0008);

printk(KERN_WARNING "%s: watchdog expired - resetting system\n",
wdt_gpi_name);

*(volatile char *) flagaddr |= 0x01;
*(volatile char *) resetaddr = powercycle ? 0x01 : 0x2;
iob();
while (1)
cpu_relax();
}


static int
wdt_gpi_notify(struct notifier_block *this, unsigned long code, void *unused)
{
if(code == SYS_DOWN || code == SYS_HALT) {
wdt_gpi_stop();
}
return NOTIFY_DONE;
}


static int __init wdt_gpi_init_module(void)
{
atomic_set(&opencnt, 1);
if (timeout > MAX_TIMEOUT_SECONDS)
timeout = MAX_TIMEOUT_SECONDS;
return driver_register(&wdt_gpi_driver);
}


static void __exit wdt_gpi_cleanup_module(void)
{
driver_unregister(&wdt_gpi_driver);
}
module_init(wdt_gpi_init_module);
module_exit(wdt_gpi_cleanup_module);



MODULE_AUTHOR("Thomas Koeller <thomas.koeller@baslerweb.com>");
MODULE_DESCRIPTION("Basler eXcite watchdog driver for gpi devices");
MODULE_VERSION("0.1");
MODULE_LICENSE("GPL");
MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds");
MODULE_PARM_DESC(resetaddr, "Address to write to to force a reset");
MODULE_PARM_DESC(flagaddr, "Address to write to boot flags to");
MODULE_PARM_DESC(nowayout, "Watchdog cannot be disabled once started");
MODULE_PARM_DESC(powercycle, "Cycle power if watchdog expires");
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