linux/drivers/watchdog/diag288_wdt.c
Bhumika Goyal b893e344bf watchdog: constify watchdog_ops structures
Declare watchdog_ops structures as const as they are only stored in the
ops field of a watchdog_device structure. This field is of type const, so
watchdog_ops structures having this property can be made const too.
Done using Coccinelle:

@r disable optional_qualifier@
identifier x;
position p;
@@
static struct watchdog_ops x@p={...};

@ok@
struct watchdog_device w;
identifier r.x;
position p;
@@
w.ops=&x@p;

@bad@
position p != {r.p,ok.p};
identifier r.x;
@@
x@p

@depends on !bad disable optional_qualifier@
identifier r.x;
@@
+const
struct watchdog_ops x;

File size details before and after patching.
First line of every .o file shows the file size before patching
and second line shows the size after patching.

   text    data     bss     dec     hex filename

   1340	    544	      0	   1884	    75c	drivers/watchdog/bcm_kona_wdt.o
   1436	    440	      0	   1876	    754	drivers/watchdog/bcm_kona_wdt.o

   1176	    544	      4	   1724	    6bc	drivers/watchdog/digicolor_wdt.o
   1272	    440	      4	   1716	    6b4	drivers/watchdog/digicolor_wdt.o

    925	    580	     89	   1594	    63a	drivers/watchdog/ep93xx_wdt.o
   1021	    476	     89	   1586	    632	drivers/watchdog/ep93xx_wdt.o

   4932	    288	     17	   5237	   1475	drivers/watchdog/s3c2410_wdt.o
   5028	    192	     17	   5237	   1475	drivers/watchdog/s3c2410_wdt.o

   1977	    292	      1	   2270	    8de	drivers/watchdog/sama5d4_wdt.o
   2073	    196	      1	   2270	    8de	drivers/watchdog/sama5d4_wdt.o

   1375	    484	      1	   1860	    744	drivers/watchdog/sirfsoc_wdt.o
   1471	    380	      1	   1852	    73c	drivers/watchdog/sirfsoc_wdt.o

Size remains the same for the files drivers/watchdog/diag288_wdt.o
drivers/watchdog/asm9260_wdt.o and drivers/watchdog/atlas7_wdt.o

The following .o files did not compile:
drivers/watchdog/sun4v_wdt.o, drivers/watchdog/sbsa_gwdt.o,
drivers/watchdog/rt2880_wdt.o, drivers/watchdog/booke_wdt.o
drivers/watchdog/mt7621_wdt.o

Signed-off-by: Bhumika Goyal <bhumirks@gmail.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
2017-02-24 14:00:23 -08:00

317 lines
7.5 KiB
C

/*
* Watchdog driver for z/VM and LPAR using the diag 288 interface.
*
* Under z/VM, expiration of the watchdog will send a "system restart" command
* to CP.
*
* The command can be altered using the module parameter "cmd". This is
* not recommended because it's only supported on z/VM but not whith LPAR.
*
* On LPAR, the watchdog will always trigger a system restart. the module
* paramter cmd is meaningless here.
*
*
* Copyright IBM Corp. 2004, 2013
* Author(s): Arnd Bergmann (arndb@de.ibm.com)
* Philipp Hachtmann (phacht@de.ibm.com)
*
*/
#define KMSG_COMPONENT "diag288_wdt"
#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/slab.h>
#include <linux/miscdevice.h>
#include <linux/watchdog.h>
#include <linux/suspend.h>
#include <asm/ebcdic.h>
#include <asm/diag.h>
#include <linux/io.h>
#include <linux/uaccess.h>
#define MAX_CMDLEN 240
#define DEFAULT_CMD "SYSTEM RESTART"
#define MIN_INTERVAL 15 /* Minimal time supported by diag88 */
#define MAX_INTERVAL 3600 /* One hour should be enough - pure estimation */
#define WDT_DEFAULT_TIMEOUT 30
/* Function codes - init, change, cancel */
#define WDT_FUNC_INIT 0
#define WDT_FUNC_CHANGE 1
#define WDT_FUNC_CANCEL 2
#define WDT_FUNC_CONCEAL 0x80000000
/* Action codes for LPAR watchdog */
#define LPARWDT_RESTART 0
static char wdt_cmd[MAX_CMDLEN] = DEFAULT_CMD;
static bool conceal_on;
static bool nowayout_info = WATCHDOG_NOWAYOUT;
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Arnd Bergmann <arndb@de.ibm.com>");
MODULE_AUTHOR("Philipp Hachtmann <phacht@de.ibm.com>");
MODULE_DESCRIPTION("System z diag288 Watchdog Timer");
module_param_string(cmd, wdt_cmd, MAX_CMDLEN, 0644);
MODULE_PARM_DESC(cmd, "CP command that is run when the watchdog triggers (z/VM only)");
module_param_named(conceal, conceal_on, bool, 0644);
MODULE_PARM_DESC(conceal, "Enable the CONCEAL CP option while the watchdog is active (z/VM only)");
module_param_named(nowayout, nowayout_info, bool, 0444);
MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default = CONFIG_WATCHDOG_NOWAYOUT)");
MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
MODULE_ALIAS("vmwatchdog");
static int __diag288(unsigned int func, unsigned int timeout,
unsigned long action, unsigned int len)
{
register unsigned long __func asm("2") = func;
register unsigned long __timeout asm("3") = timeout;
register unsigned long __action asm("4") = action;
register unsigned long __len asm("5") = len;
int err;
err = -EINVAL;
asm volatile(
" diag %1, %3, 0x288\n"
"0: la %0, 0\n"
"1:\n"
EX_TABLE(0b, 1b)
: "+d" (err) : "d"(__func), "d"(__timeout),
"d"(__action), "d"(__len) : "1", "cc");
return err;
}
static int __diag288_vm(unsigned int func, unsigned int timeout,
char *cmd, size_t len)
{
diag_stat_inc(DIAG_STAT_X288);
return __diag288(func, timeout, virt_to_phys(cmd), len);
}
static int __diag288_lpar(unsigned int func, unsigned int timeout,
unsigned long action)
{
diag_stat_inc(DIAG_STAT_X288);
return __diag288(func, timeout, action, 0);
}
static unsigned long wdt_status;
#define DIAG_WDOG_BUSY 0
static int wdt_start(struct watchdog_device *dev)
{
char *ebc_cmd;
size_t len;
int ret;
unsigned int func;
if (test_and_set_bit(DIAG_WDOG_BUSY, &wdt_status))
return -EBUSY;
ret = -ENODEV;
if (MACHINE_IS_VM) {
ebc_cmd = kmalloc(MAX_CMDLEN, GFP_KERNEL);
if (!ebc_cmd) {
clear_bit(DIAG_WDOG_BUSY, &wdt_status);
return -ENOMEM;
}
len = strlcpy(ebc_cmd, wdt_cmd, MAX_CMDLEN);
ASCEBC(ebc_cmd, MAX_CMDLEN);
EBC_TOUPPER(ebc_cmd, MAX_CMDLEN);
func = conceal_on ? (WDT_FUNC_INIT | WDT_FUNC_CONCEAL)
: WDT_FUNC_INIT;
ret = __diag288_vm(func, dev->timeout, ebc_cmd, len);
WARN_ON(ret != 0);
kfree(ebc_cmd);
} else {
ret = __diag288_lpar(WDT_FUNC_INIT,
dev->timeout, LPARWDT_RESTART);
}
if (ret) {
pr_err("The watchdog cannot be activated\n");
clear_bit(DIAG_WDOG_BUSY, &wdt_status);
return ret;
}
return 0;
}
static int wdt_stop(struct watchdog_device *dev)
{
int ret;
diag_stat_inc(DIAG_STAT_X288);
ret = __diag288(WDT_FUNC_CANCEL, 0, 0, 0);
clear_bit(DIAG_WDOG_BUSY, &wdt_status);
return ret;
}
static int wdt_ping(struct watchdog_device *dev)
{
char *ebc_cmd;
size_t len;
int ret;
unsigned int func;
ret = -ENODEV;
if (MACHINE_IS_VM) {
ebc_cmd = kmalloc(MAX_CMDLEN, GFP_KERNEL);
if (!ebc_cmd)
return -ENOMEM;
len = strlcpy(ebc_cmd, wdt_cmd, MAX_CMDLEN);
ASCEBC(ebc_cmd, MAX_CMDLEN);
EBC_TOUPPER(ebc_cmd, MAX_CMDLEN);
/*
* It seems to be ok to z/VM to use the init function to
* retrigger the watchdog. On LPAR WDT_FUNC_CHANGE must
* be used when the watchdog is running.
*/
func = conceal_on ? (WDT_FUNC_INIT | WDT_FUNC_CONCEAL)
: WDT_FUNC_INIT;
ret = __diag288_vm(func, dev->timeout, ebc_cmd, len);
WARN_ON(ret != 0);
kfree(ebc_cmd);
} else {
ret = __diag288_lpar(WDT_FUNC_CHANGE, dev->timeout, 0);
}
if (ret)
pr_err("The watchdog timer cannot be started or reset\n");
return ret;
}
static int wdt_set_timeout(struct watchdog_device * dev, unsigned int new_to)
{
dev->timeout = new_to;
return wdt_ping(dev);
}
static const struct watchdog_ops wdt_ops = {
.owner = THIS_MODULE,
.start = wdt_start,
.stop = wdt_stop,
.ping = wdt_ping,
.set_timeout = wdt_set_timeout,
};
static struct watchdog_info wdt_info = {
.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
.firmware_version = 0,
.identity = "z Watchdog",
};
static struct watchdog_device wdt_dev = {
.parent = NULL,
.info = &wdt_info,
.ops = &wdt_ops,
.bootstatus = 0,
.timeout = WDT_DEFAULT_TIMEOUT,
.min_timeout = MIN_INTERVAL,
.max_timeout = MAX_INTERVAL,
};
/*
* It makes no sense to go into suspend while the watchdog is running.
* Depending on the memory size, the watchdog might trigger, while we
* are still saving the memory.
*/
static int wdt_suspend(void)
{
if (test_and_set_bit(DIAG_WDOG_BUSY, &wdt_status)) {
pr_err("Linux cannot be suspended while the watchdog is in use\n");
return notifier_from_errno(-EBUSY);
}
return NOTIFY_DONE;
}
static int wdt_resume(void)
{
clear_bit(DIAG_WDOG_BUSY, &wdt_status);
return NOTIFY_DONE;
}
static int wdt_power_event(struct notifier_block *this, unsigned long event,
void *ptr)
{
switch (event) {
case PM_POST_HIBERNATION:
case PM_POST_SUSPEND:
return wdt_resume();
case PM_HIBERNATION_PREPARE:
case PM_SUSPEND_PREPARE:
return wdt_suspend();
default:
return NOTIFY_DONE;
}
}
static struct notifier_block wdt_power_notifier = {
.notifier_call = wdt_power_event,
};
static int __init diag288_init(void)
{
int ret;
char ebc_begin[] = {
194, 197, 199, 201, 213
};
watchdog_set_nowayout(&wdt_dev, nowayout_info);
if (MACHINE_IS_VM) {
if (__diag288_vm(WDT_FUNC_INIT, 15,
ebc_begin, sizeof(ebc_begin)) != 0) {
pr_err("The watchdog cannot be initialized\n");
return -EINVAL;
}
} else {
if (__diag288_lpar(WDT_FUNC_INIT, 30, LPARWDT_RESTART)) {
pr_err("The watchdog cannot be initialized\n");
return -EINVAL;
}
}
if (__diag288_lpar(WDT_FUNC_CANCEL, 0, 0)) {
pr_err("The watchdog cannot be deactivated\n");
return -EINVAL;
}
ret = register_pm_notifier(&wdt_power_notifier);
if (ret)
return ret;
ret = watchdog_register_device(&wdt_dev);
if (ret)
unregister_pm_notifier(&wdt_power_notifier);
return ret;
}
static void __exit diag288_exit(void)
{
watchdog_unregister_device(&wdt_dev);
unregister_pm_notifier(&wdt_power_notifier);
}
module_init(diag288_init);
module_exit(diag288_exit);