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Commit baae0d6b authored by Wim Van Sebroeck's avatar Wim Van Sebroeck
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[WATCHDOG] v2.6.6 sc520_wdt.c-patch1 

Clean-up (general stuff: comments, keep module parameters together, ...)
Added clear definitions for the Watchdog Timer Control Register bits
Made start, stop and keepalive return 0 if successful
Fixed nowayout behaviour so that it is consistent with other watchdog drivers
Fixed release behaviour so that it is consistent with other watchdog drivers
Added wdt_set_heartbeat function to set the timeout/heartbeat of the watchdog
Made sure that memory remapping (wdtmrctl) is done before misc_register is started
MMCR_BASE_DEFAULT was wrong (Bug 2497 reported by Sean Young)

Tested by Sean Young
parent 630fb05e
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Showing with 125 additions and 110 deletions
drivers/char/watchdog/sc520_wdt.c
View file @ baae0d6b
......@@ -23,22 +23,23 @@
* - Switched to private locks not lock_kernel
* - Used ioremap/writew/readw
* - Added NOWAYOUT support
*
* 4/12 - 2002 Changes by Rob Radez <rob@osinvestor.com>
* - Change comments
* - Eliminate fop_llseek
* - Change CONFIG_WATCHDOG_NOWAYOUT semantics
* - Add KERN_* tags to printks
* - fix possible wdt_is_open race
* - Report proper capabilities in watchdog_info
* - Add WDIOC_{GETSTATUS, GETBOOTSTATUS, SETTIMEOUT,
* GETTIMEOUT, SETOPTIONS} ioctls
* 09/8 - 2003 Changes by Wim Van Sebroeck <wim@iguana.be>
* - cleanup of trailing spaces
* - added extra printk's for startup problems
* - use module_param
* - made timeout (the emulated heartbeat) a module_param
* - made the keepalive ping an internal subroutine
* 4/12 - 2002 Changes by Rob Radez <rob@osinvestor.com>
* - Change comments
* - Eliminate fop_llseek
* - Change CONFIG_WATCHDOG_NOWAYOUT semantics
* - Add KERN_* tags to printks
* - fix possible wdt_is_open race
* - Report proper capabilities in watchdog_info
* - Add WDIOC_{GETSTATUS, GETBOOTSTATUS, SETTIMEOUT,
* GETTIMEOUT, SETOPTIONS} ioctls
* 09/8 - 2003 Changes by Wim Van Sebroeck <wim@iguana.be>
* - cleanup of trailing spaces
* - added extra printk's for startup problems
* - use module_param
* - made timeout (the emulated heartbeat) a module_param
* - made the keepalive ping an internal subroutine
* 3/27 - 2004 Changes by Sean Young <sean@mess.org>
* - set MMCR_BASE_DEFAULT to 0xfffef000
*
* This WDT driver is different from most other Linux WDT
* drivers in that the driver will ping the watchdog by itself,
......@@ -65,8 +66,16 @@
#include <asm/uaccess.h>
#include <asm/system.h>
#define OUR_NAME "sc520_wdt"
#define PFX OUR_NAME ": "
/*
* The SC520 can timeout anywhere from 492us to 32.21s.
* The AMD Elan SC520 timeout value is 492us times a power of 2 (0-7)
*
* 0: 492us 2: 1.01s 4: 4.03s 6: 16.22s
* 1: 503ms 3: 2.01s 5: 8.05s 7: 32.21s
*
* We will program the SC520 watchdog for a timeout of 2.01s.
* If we reset the watchdog every ~250ms we should be safe.
*/
......@@ -83,25 +92,33 @@ static int timeout = WATCHDOG_TIMEOUT; /* in seconds, will be multiplied by HZ t
module_param(timeout, int, 0);
MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds. (1<=timeout<=3600, default=" __MODULE_STRING(WATCHDOG_TIMEOUT) ")");
/*
* AMD Elan SC520 timeout value is 492us times a power of 2 (0-7)
*
* 0: 492us 2: 1.01s 4: 4.03s 6: 16.22s
* 1: 503ms 3: 2.01s 5: 8.05s 7: 32.21s
*/
#define TIMEOUT_EXPONENT ( 1 << 3 ) /* 0x08 = 2.01s */
/* #define MMCR_BASE_DEFAULT 0xfffef000 */
#define MMCR_BASE_DEFAULT ((__u16 *)0xffffe)
#define OFFS_WDTMRCTL ((unsigned int)0xcb0)
#define WDT_ENB 0x8000 /* [15] Watchdog Timer Enable */
#define WDT_WRST_ENB 0x4000 /* [14] Watchdog Timer Reset Enable */
#ifdef CONFIG_WATCHDOG_NOWAYOUT
static int nowayout = 1;
#else
static int nowayout = 0;
#endif
#define OUR_NAME "sc520_wdt"
#define PFX OUR_NAME ": "
module_param(nowayout, int, 0);
MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=CONFIG_WATCHDOG_NOWAYOUT)");
#define WRT_DOG(data) *wdtmrctl=data
/*
* AMD Elan SC520 - Watchdog Timer Registers
*/
#define MMCR_BASE_DEFAULT 0xfffef000 /* The default base address */
#define OFFS_WDTMRCTL 0xCB0 /* Watchdog Timer Control Register */
/* WDT Control Register bit definitions */
#define WDT_EXP_SEL_01 0x0001 /* [01] Time-out = 496 us (with 33 Mhz clk). */
#define WDT_EXP_SEL_02 0x0002 /* [02] Time-out = 508 ms (with 33 Mhz clk). */
#define WDT_EXP_SEL_03 0x0004 /* [03] Time-out = 1.02 s (with 33 Mhz clk). */
#define WDT_EXP_SEL_04 0x0008 /* [04] Time-out = 2.03 s (with 33 Mhz clk). */
#define WDT_EXP_SEL_05 0x0010 /* [05] Time-out = 4.07 s (with 33 Mhz clk). */
#define WDT_EXP_SEL_06 0x0020 /* [06] Time-out = 8.13 s (with 33 Mhz clk). */
#define WDT_EXP_SEL_07 0x0040 /* [07] Time-out = 16.27s (with 33 Mhz clk). */
#define WDT_EXP_SEL_08 0x0080 /* [08] Time-out = 32.54s (with 33 Mhz clk). */
#define WDT_IRQ_FLG 0x1000 /* [12] Interrupt Request Flag */
#define WDT_WRST_ENB 0x4000 /* [14] Watchdog Timer Reset Enable */
#define WDT_ENB 0x8000 /* [15] Watchdog Timer Enable */
static __u16 *wdtmrctl;
......@@ -112,15 +129,6 @@ static unsigned long wdt_is_open;
static char wdt_expect_close;
static spinlock_t wdt_spinlock;
#ifdef CONFIG_WATCHDOG_NOWAYOUT
static int nowayout = 1;
#else
static int nowayout = 0;
#endif
module_param(nowayout, int, 0);
MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=CONFIG_WATCHDOG_NOWAYOUT)");
/*
* Whack the dog
*/
......@@ -147,7 +155,7 @@ static void wdt_timer_ping(unsigned long data)
}
/*
* Utility routines
* Utility routines
*/
static void wdt_config(int writeval)
......@@ -157,10 +165,10 @@ static void wdt_config(int writeval)
/* buy some time (ping) */
spin_lock_irqsave(&wdt_spinlock, flags);
dummy=readw(wdtmrctl); /* ensure write synchronization */
dummy=readw(wdtmrctl); /* ensure write synchronization */
writew(0xAAAA, wdtmrctl);
writew(0x5555, wdtmrctl);
/* make WDT configuration register writable one time */
/* unlock WDT = make WDT configuration register writable one time */
writew(0x3333, wdtmrctl);
writew(0xCCCC, wdtmrctl);
/* write WDT configuration register */
......@@ -168,7 +176,7 @@ static void wdt_config(int writeval)
spin_unlock_irqrestore(&wdt_spinlock, flags);
}
static void wdt_startup(void)
static int wdt_startup(void)
{
next_heartbeat = jiffies + (timeout * HZ);
......@@ -176,28 +184,43 @@ static void wdt_startup(void)
timer.expires = jiffies + WDT_INTERVAL;
add_timer(&timer);
wdt_config(WDT_ENB | WDT_WRST_ENB | TIMEOUT_EXPONENT);
/* Start the watchdog */
wdt_config(WDT_ENB | WDT_WRST_ENB | WDT_EXP_SEL_04);
printk(KERN_INFO PFX "Watchdog timer is now enabled.\n");
return 0;
}
static void wdt_turnoff(void)
static int wdt_turnoff(void)
{
if (!nowayout) {
/* Stop the timer */
del_timer(&timer);
wdt_config(0);
printk(KERN_INFO PFX "Watchdog timer is now disabled...\n");
}
/* Stop the timer */
del_timer(&timer);
/* Stop the watchdog */
wdt_config(0);
printk(KERN_INFO PFX "Watchdog timer is now disabled...\n");
return 0;
}
static void wdt_keepalive(void)
static int wdt_keepalive(void)
{
/* user land ping */
next_heartbeat = jiffies + (timeout * HZ);
return 0;
}
static int wdt_set_heartbeat(int t)
{
if ((t < 1) || (t > 3600)) /* arbitrary upper limit */
return -EINVAL;
timeout = t;
return 0;
}
/*
* /dev/watchdog handling
* /dev/watchdog handling
*/
static ssize_t fop_write(struct file * file, const char * buf, size_t count, loff_t * ppos)
......@@ -207,10 +230,8 @@ static ssize_t fop_write(struct file * file, const char * buf, size_t count, lof
return -ESPIPE;
/* See if we got the magic character 'V' and reload the timer */
if(count)
{
if (!nowayout)
{
if(count) {
if (!nowayout) {
size_t ofs;
/* note: just in case someone wrote the magic character
......@@ -248,11 +269,11 @@ static int fop_open(struct inode * inode, struct file * file)
static int fop_close(struct inode * inode, struct file * file)
{
if(wdt_expect_close == 42)
if(wdt_expect_close == 42) {
wdt_turnoff();
else {
del_timer(&timer);
printk(KERN_CRIT PFX "device file closed unexpectedly. Will not stop the WDT!\n");
} else {
printk(KERN_CRIT PFX "Unexpected close, not stopping watchdog!\n");
wdt_keepalive();
}
clear_bit(0, &wdt_is_open);
wdt_expect_close = 0;
......@@ -262,8 +283,7 @@ static int fop_close(struct inode * inode, struct file * file)
static int fop_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
unsigned long arg)
{
static struct watchdog_info ident=
{
static struct watchdog_info ident = {
.options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE,
.firmware_version = 1,
.identity = "SC520",
......@@ -307,10 +327,9 @@ static int fop_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
if(get_user(new_timeout, (int *)arg))
return -EFAULT;
if(new_timeout < 1 || new_timeout > 3600) /* arbitrary upper limit */
if(wdt_set_heartbeat(new_timeout))
return -EINVAL;
timeout = new_timeout;
wdt_keepalive();
/* Fall through */
}
......@@ -351,81 +370,77 @@ static int wdt_notify_sys(struct notifier_block *this, unsigned long code,
* turn the timebomb registers off.
*/
static struct notifier_block wdt_notifier=
{
static struct notifier_block wdt_notifier = {
.notifier_call = wdt_notify_sys,
};
static void __exit sc520_wdt_unload(void)
{
wdt_turnoff();
if (!nowayout)
wdt_turnoff();
/* Deregister */
misc_deregister(&wdt_miscdev);
iounmap(wdtmrctl);
unregister_reboot_notifier(&wdt_notifier);
iounmap(wdtmrctl);
}
static int __init sc520_wdt_init(void)
{
int rc = -EBUSY;
unsigned long cbar;
unsigned long MMCR_BASE;
spin_lock_init(&wdt_spinlock);
if(timeout < 1 || timeout > 3600) /* arbitrary upper limit */
{
timeout = WATCHDOG_TIMEOUT;
printk(KERN_INFO PFX "timeout value must be 1<=x<=3600, using %d\n",
timeout);
}
init_timer(&timer);
timer.function = wdt_timer_ping;
timer.data = 0;
rc = misc_register(&wdt_miscdev);
if (rc)
{
printk(KERN_ERR PFX "cannot register miscdev on minor=%d (err=%d)\n",
wdt_miscdev.minor, rc);
goto err_out_region2;
}
rc = register_reboot_notifier(&wdt_notifier);
if (rc)
{
printk(KERN_ERR PFX "cannot register reboot notifier (err=%d)\n",
rc);
goto err_out_miscdev;
/* Check that the timeout value is within it's range ; if not reset to the default */
if (wdt_set_heartbeat(timeout)) {
wdt_set_heartbeat(WATCHDOG_TIMEOUT);
printk(KERN_INFO PFX "timeout value must be 1<=timeout<=3600, using %d\n",
WATCHDOG_TIMEOUT);
}
/* get the Base Address Register */
/* get the Base Address Register:
* If the ENB bit [31] of CBAR is set => MMCR alias is enabled and MMCR base address is
* the contents of CBAR[29-12].
* if ENB bit is 0 => MMCR alias is disabled and the MMCR base address is the default
* value. */
cbar = inl_p(0xfffc);
printk(KERN_INFO PFX "CBAR: 0x%08lx\n", cbar);
/* check if MMCR aliasing bit is set */
if (cbar & 0x80000000) {
printk(KERN_INFO PFX "MMCR Aliasing enabled.\n");
wdtmrctl = (__u16 *)(cbar & 0x3fffffff);
MMCR_BASE = (cbar & 0x3fffffff);
} else {
printk(KERN_INFO PFX "!!! WARNING !!!\n"
"\t MMCR Aliasing found NOT enabled!\n"
"\t Using default value of: %p\n"
"\t This has not been tested!\n"
"\t Please email Scott Jennings <smj@oro.net>\n"
"\t and Bill Jennings <bj@oro.net> if it works!\n"
, MMCR_BASE_DEFAULT
);
wdtmrctl = MMCR_BASE_DEFAULT;
printk(KERN_INFO PFX "MMCR Aliasing NOT enabled. Using default value.\n");
MMCR_BASE = MMCR_BASE_DEFAULT;
}
wdtmrctl = (__u16 *)((char *)wdtmrctl + OFFS_WDTMRCTL);
wdtmrctl = ioremap((unsigned long)wdtmrctl, 2);
wdtmrctl = ioremap((unsigned long)(MMCR_BASE + OFFS_WDTMRCTL), 2);
if (!wdtmrctl) {
printk (KERN_ERR PFX "Unable to remap memory.\n");
printk(KERN_ERR PFX "Unable to remap memory\n");
rc = -ENOMEM;
goto err_out_region2;
}
rc = register_reboot_notifier(&wdt_notifier);
if (rc) {
printk(KERN_ERR PFX "cannot register reboot notifier (err=%d)\n",
rc);
goto err_out_ioremap;
}
rc = misc_register(&wdt_miscdev);
if (rc) {
printk(KERN_ERR PFX "cannot register miscdev on minor=%d (err=%d)\n",
WATCHDOG_MINOR, rc);
goto err_out_notifier;
}
printk(KERN_INFO PFX "WDT driver for SC520 initialised. timeout=%d sec (nowayout=%d)\n",
timeout,nowayout);
......@@ -433,8 +448,8 @@ static int __init sc520_wdt_init(void)
err_out_notifier:
unregister_reboot_notifier(&wdt_notifier);
err_out_miscdev:
misc_deregister(&wdt_miscdev);
err_out_ioremap:
iounmap(wdtmrctl);
err_out_region2:
return rc;
}
......
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