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Commit 646f919e authored by Philipp Hachtmann's avatar Philipp Hachtmann Committed by Martin Schwidefsky
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s390/watchdog: add support for LPAR operation (diag288) 



Add the LPAR variant of the diag 288 watchdog to the driver.
The only available action on timeout for LPAR is a PSW restart.

Signed-off-by: default avatarPhilipp Hachtmann <phacht@de.ibm.com>
Signed-off-by: default avatarMartin Schwidefsky <schwidefsky@de.ibm.com>
parent f7a94db4

drivers/watchdog/Kconfig

+2 −0
Original line number Diff line number Diff line
@@ -1304,6 +1304,8 @@ config DIAG288_WATCHDOG 
	  provide a virtual watchdog timer to their guest that cause a

	  user define Control Program command to be executed after a

	  timeout.

	  LPAR provides a very similar interface. This driver handles

	  both.



	  To compile this driver as a module, choose M here. The module

	  will be called vmwatchdog.

drivers/watchdog/diag288_wdt.c

+33 −4
Original line number Diff line number Diff line 
/*

 * Watchdog driver for z/VM using the diag 288 interface.

 * 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".

 * 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)
@@ -41,6 +46,9 @@ 
#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;
@@ -89,6 +97,12 @@ static int __diag288_vm(unsigned int func, unsigned int timeout, 
	return __diag288(func, timeout, virt_to_phys(cmd), len);

}



static int __diag288_lpar(unsigned int func, unsigned int timeout,

			  unsigned long action)

{

	return __diag288(func, timeout, action, 0);

}



static int wdt_start(struct watchdog_device *dev)

{

	char *ebc_cmd;
@@ -113,6 +127,11 @@ static int wdt_start(struct watchdog_device *dev) 
		kfree(ebc_cmd);

	}



	if (MACHINE_IS_LPAR) {

		ret = __diag288_lpar(WDT_FUNC_INIT,

				     dev->timeout, LPARWDT_RESTART);

	}



	if (ret) {

		pr_err("The watchdog cannot be activated\n");

		return ret;
@@ -149,7 +168,8 @@ static int wdt_ping(struct watchdog_device *dev) 


		/*

		 * It seems to be ok to z/VM to use the init function to

		 * retrigger the watchdog.

		 * 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;
@@ -159,6 +179,9 @@ static int wdt_ping(struct watchdog_device *dev) 
		kfree(ebc_cmd);

	}



	if (MACHINE_IS_LPAR)

		ret = __diag288_lpar(WDT_FUNC_CHANGE, dev->timeout, 0);



	if (ret)

		pr_err("The watchdog timer cannot be started or reset\n");

	return ret;
@@ -256,12 +279,18 @@ static int __init diag288_init(void) 
			pr_err("The watchdog cannot be initialized\n");

			return -EINVAL;

		}

	} else if (MACHINE_IS_LPAR) {

		pr_info("The watchdog device driver detected an LPAR environment\n");

		if (__diag288_lpar(WDT_FUNC_INIT, 30, LPARWDT_RESTART)) {

			pr_err("The watchdog cannot be initialized\n");

			return -EINVAL;

		}

	} else {

		pr_err("Linux runs in an environment that does not support the diag288 watchdog\n");

		return -ENODEV;

	}



	if (__diag288_vm(WDT_FUNC_CANCEL, 0, NULL, 0)) {

	if (__diag288_lpar(WDT_FUNC_CANCEL, 0, 0)) {

		pr_err("The watchdog cannot be deactivated\n");

		return -EINVAL;

	}