path: root/drivers/xen/xenbus/xenbus_probe.c

/******************************************************************************
 * Talks to Xen Store to figure out what devices we have.
 *
 * Copyright (C) 2005 Rusty Russell, IBM Corporation
 * Copyright (C) 2005 Mike Wray, Hewlett-Packard
 * Copyright (C) 2005, 2006 XenSource Ltd
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License version 2
 * as published by the Free Software Foundation; or, when distributed
 * separately from the Linux kernel or incorporated into other
 * software packages, subject to the following license:
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this source file (the "Software"), to deal in the Software without
 * restriction, including without limitation the rights to use, copy, modify,
 * merge, publish, distribute, sublicense, and/or sell copies of the Software,
 * and to permit persons to whom the Software is furnished to do so, subject to
 * the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
 * IN THE SOFTWARE.
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#define dev_fmt pr_fmt

#define DPRINTK(fmt, args...)				\
	pr_debug("xenbus_probe (%s:%d) " fmt ".\n",	\
		 __func__, __LINE__, ##args)

#include <linux/kernel.h>
#include <linux/err.h>
#include <linux/string.h>
#include <linux/ctype.h>
#include <linux/fcntl.h>
#include <linux/mm.h>
#include <linux/proc_fs.h>
#include <linux/notifier.h>
#include <linux/kthread.h>
#include <linux/mutex.h>
#include <linux/io.h>
#include <linux/slab.h>
#include <linux/module.h>

#include <asm/page.h>
#include <asm/xen/hypervisor.h>

#include <xen/xen.h>
#include <xen/xenbus.h>
#include <xen/events.h>
#include <xen/xen-ops.h>
#include <xen/page.h>

#include <xen/hvm.h>

#include "xenbus.h"


static int xs_init_irq;
int xen_store_evtchn;
EXPORT_SYMBOL_GPL(xen_store_evtchn);

struct xenstore_domain_interface *xen_store_interface;
EXPORT_SYMBOL_GPL(xen_store_interface);

enum xenstore_init xen_store_domain_type;
EXPORT_SYMBOL_GPL(xen_store_domain_type);

static unsigned long xen_store_gfn;

static BLOCKING_NOTIFIER_HEAD(xenstore_chain);

/* If something in array of ids matches this device, return it. */
static const struct xenbus_device_id *
match_device(const struct xenbus_device_id *arr, struct xenbus_device *dev)
{
	for (; *arr->devicetype != '\0'; arr++) {
		if (!strcmp(arr->devicetype, dev->devicetype))
			return arr;
	}
	return NULL;
}

int xenbus_match(struct device *_dev, struct device_driver *_drv)
{
	struct xenbus_driver *drv = to_xenbus_driver(_drv);

	if (!drv->ids)
		return 0;

	return match_device(drv->ids, to_xenbus_device(_dev)) != NULL;
}
EXPORT_SYMBOL_GPL(xenbus_match);


static void free_otherend_details(struct xenbus_device *dev)
{
	kfree(dev->otherend);
	dev->otherend = NULL;
}


static void free_otherend_watch(struct xenbus_device *dev)
{
	if (dev->otherend_watch.node) {
		unregister_xenbus_watch(&dev->otherend_watch);
		kfree(dev->otherend_watch.node);
		dev->otherend_watch.node = NULL;
	}
}


static int talk_to_otherend(struct xenbus_device *dev)
{
	struct xenbus_driver *drv = to_xenbus_driver(dev->dev.driver);

	free_otherend_watch(dev);
	free_otherend_details(dev);

	return drv->read_otherend_details(dev);
}



static int watch_otherend(struct xenbus_device *dev)
{
	struct xen_bus_type *bus =
		container_of(dev->dev.bus, struct xen_bus_type, bus);

	return xenbus_watch_pathfmt(dev, &dev->otherend_watch,
				    bus->otherend_will_handle,
				    bus->otherend_changed,
				    "%s/%s", dev->otherend, "state");
}


int xenbus_read_otherend_details(struct xenbus_device *xendev,
				 char *id_node, char *path_node)
{
	int err = xenbus_gather(XBT_NIL, xendev->nodename,
				id_node, "%i", &xendev->otherend_id,
				path_node, NULL, &xendev->otherend,
				NULL);
	if (err) {
		xenbus_dev_fatal(xendev, err,
				 "reading other end details from %s",
				 xendev->nodename);
		return err;
	}
	if (strlen(xendev->otherend) == 0 ||
	    !xenbus_exists(XBT_NIL, xendev->otherend, "")) {
		xenbus_dev_fatal(xendev, -ENOENT,
				 "unable to read other end from %s.  "
				 "missing or inaccessible.",
				 xendev->nodename);
		free_otherend_details(xendev);
		return -ENOENT;
	}

	return 0;
}
EXPORT_SYMBOL_GPL(xenbus_read_otherend_details);

void xenbus_otherend_changed(struct xenbus_watch *watch,
			     const char *path, const char *token,
			     int ignore_on_shutdown)
{
	struct xenbus_device *dev =
		container_of(watch, struct xenbus_device, otherend_watch);
	struct xenbus_driver *drv = to_xenbus_driver(dev->dev.driver);
	enum xenbus_state state;

	/* Protect us against watches firing on old details when the otherend
	   details change, say immediately after a resume. */
	if (!dev->otherend ||
	    strncmp(dev->otherend, path, strlen(dev->otherend