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Commit ed7279ae authored by Greg Kroah-Hartman's avatar Greg Kroah-Hartman
Browse files

greybus: svc: add a "watchdog" to check the network health 



Now that we have a svc ping command, let's add a watchdog to call it
every so often (1 second at the moment.)  If it finds something went
wrong, post a stern message to the kernel log and call:
	start unipro_reset
to reset the whole greybus hardware subsystem.

Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@google.com>
Reviewed-by: default avatarRui Miguel Silva <rui.silva@linaro.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@google.com>
parent 0f65fb1e

drivers/staging/greybus/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -8,6 +8,7 @@ greybus-y := core.o \ 
		protocol.o	\

		control.o	\

		svc.o		\

		svc_watchdog.o	\

		firmware.o	\

		operation.o	\

		legacy.o

drivers/staging/greybus/svc.c

+8 −0
Original line number Diff line number Diff line
@@ -436,6 +436,13 @@ static int gb_svc_hello(struct gb_operation *op) 
		return ret;

	}



	ret = gb_svc_watchdog_create(svc);

	if (ret) {

		dev_err(&svc->dev, "failed to create watchdog: %d\n", ret);

		input_unregister_device(svc->input);

		device_del(&svc->dev);

	}



	return 0;

}
@@ -963,6 +970,7 @@ void gb_svc_del(struct gb_svc *svc) 
	 * from the request handler.

	 */

	if (device_is_registered(&svc->dev)) {

		gb_svc_watchdog_destroy(svc);

		input_unregister_device(svc->input);

		device_del(&svc->dev);

	}

drivers/staging/greybus/svc.h

+5 −0
Original line number Diff line number Diff line
@@ -16,6 +16,8 @@ enum gb_svc_state { 
	GB_SVC_STATE_SVC_HELLO,

};



struct gb_svc_watchdog;



struct gb_svc {

	struct device		dev;
@@ -33,6 +35,7 @@ struct gb_svc { 


	struct input_dev        *input;

	char                    *input_phys;

	struct gb_svc_watchdog	*watchdog;

};

#define to_gb_svc(d) container_of(d, struct gb_svc, d)
@@ -56,6 +59,8 @@ int gb_svc_intf_set_power_mode(struct gb_svc *svc, u8 intf_id, u8 hs_series, 
			       u8 rx_mode, u8 rx_gear, u8 rx_nlanes,

			       u8 flags, u32 quirks);

int gb_svc_ping(struct gb_svc *svc);

int gb_svc_watchdog_create(struct gb_svc *svc);

void gb_svc_watchdog_destroy(struct gb_svc *svc);



int gb_svc_protocol_init(void);

void gb_svc_protocol_exit(void);

drivers/staging/greybus/svc_watchdog.c

0 → 100644
+109 −0
Original line number Diff line number Diff line 
/*

 * SVC Greybus "watchdog" driver.

 *

 * Copyright 2016 Google Inc.

 *

 * Released under the GPLv2 only.

 */



#include <linux/delay.h>

#include <linux/workqueue.h>

#include "greybus.h"



#define SVC_WATCHDOG_PERIOD	(2*HZ)



struct gb_svc_watchdog {

	struct delayed_work	work;

	struct gb_svc		*svc;

	bool			finished;

};



static struct delayed_work reset_work;



static void greybus_reset(struct work_struct *work)

{

	static char start_path[256] = "/system/bin/start";

	static char *envp[] = {

		"HOME=/",

		"PATH=/sbin:/vendor/bin:/system/sbin:/system/bin:/system/xbin",

		NULL,

	};

	static char *argv[] = {

		start_path,

		"unipro_reset",

		NULL,

	};



	printk(KERN_ERR "svc_watchdog: calling \"%s %s\" to reset greybus network!\n",

	       argv[0], argv[1]);

	call_usermodehelper(start_path, argv, envp, UMH_WAIT_EXEC);

}



static void do_work(struct work_struct *work)

{

	struct gb_svc_watchdog *watchdog;

	struct gb_svc *svc;

	int retval;



	watchdog = container_of(work, struct gb_svc_watchdog, work.work);

	svc = watchdog->svc;



	dev_dbg(&svc->dev, "%s: ping.\n", __func__);

	retval = gb_svc_ping(svc);

	if (retval) {

		/*

		 * Something went really wrong, let's warn userspace and then

		 * pull the plug and reset the whole greybus network.

		 * We need to do this outside of this workqueue as we will be

		 * tearing down the svc device itself.  So queue up

		 * yet-another-callback to do that.

		 */

		dev_err(&svc->dev,

			"SVC ping has returned %d, something is wrong!!!\n",

			retval);

		dev_err(&svc->dev, "Resetting the greybus network, watch out!!!\n");



		INIT_DELAYED_WORK(&reset_work, greybus_reset);

		queue_delayed_work(system_wq, &reset_work, HZ/2);

		return;

	}



	/* resubmit our work to happen again, if we are still "alive" */

	if (!watchdog->finished)

		queue_delayed_work(system_wq, &watchdog->work,

				   SVC_WATCHDOG_PERIOD);

}



int gb_svc_watchdog_create(struct gb_svc *svc)

{

	struct gb_svc_watchdog *watchdog;



	if (svc->watchdog)

		return 0;



	watchdog = kmalloc(sizeof(*watchdog), GFP_KERNEL);

	if (!watchdog)

		return -ENOMEM;



	watchdog->finished = false;

	watchdog->svc = svc;

	INIT_DELAYED_WORK(&watchdog->work, do_work);

	svc->watchdog = watchdog;



	queue_delayed_work(system_wq, &watchdog->work,

			   SVC_WATCHDOG_PERIOD);

	return 0;

}



void gb_svc_watchdog_destroy(struct gb_svc *svc)

{

	struct gb_svc_watchdog *watchdog = svc->watchdog;



	if (!watchdog)

		return;



	watchdog->finished = true;

	cancel_delayed_work_sync(&watchdog->work);

	svc->watchdog = NULL;

	kfree(watchdog);

}