/******************************************************************************
* Copyright (C) 2010 Spectra Logic Corporation
* Copyright (C) 2008 Doug Rabson
* Copyright (C) 2005 Rusty Russell, IBM Corporation
* Copyright (C) 2005 Mike Wray, Hewlett-Packard
* Copyright (C) 2005 XenSource Ltd
*
* This file may be 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.
*/
/**
* \file xenbusb.c
*
* \brief Shared support functions for managing the NewBus busses that contain
* Xen front and back end device instances.
*
* The NewBus implementation of XenBus attaches a xenbusb_front and xenbusb_back
* child bus to the xenstore device. This strategy allows the small differences
* in the handling of XenBus operations for front and back devices to be handled
* as overrides in xenbusb_front/back.c. Front and back specific device
* classes are also provided so device drivers can register for the devices they
* can handle without the need to filter within their probe routines. The
* net result is a device hierarchy that might look like this:
*
* xenstore0/
* xenbusb_front0/
* xn0
* xbd0
* xbd1
* xenbusb_back0/
* xbbd0
* xnb0
* xnb1
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/param.h>
#include <sys/bus.h>
#include <sys/kernel.h>
#include <sys/lock.h>
#include <sys/malloc.h>
#include <sys/module.h>
#include <sys/sbuf.h>
#include <sys/sysctl.h>
#include <sys/syslog.h>
#include <sys/systm.h>
#include <sys/sx.h>
#include <sys/taskqueue.h>
#include <machine/xen/xen-os.h>
#include <machine/stdarg.h>
#include <xen/gnttab.h>
#include <xen/xenstore/xenstorevar.h>
#include <xen/xenbus/xenbusb.h>
#include <xen/xenbus/xenbusvar.h>
/*------------------------- Private Functions --------------------------------*/
/**
* \brief Deallocate XenBus device instance variables.
*
* \param ivars The instance variable block to free.
*/
static void
xenbusb_free_child_ivars(struct xenbus_device_ivars *ivars)
{
if (ivars->xd_otherend_watch.node != NULL) {
xs_unregister_watch(&ivars->xd_otherend_watch);
free(ivars->xd_otherend_watch.node, M_XENBUS);
ivars->xd_otherend_watch.node = NULL;
}
if (ivars->xd_local_watch.node != NULL) {
xs_unregister_watch(&ivars->xd_local_watch);
ivars->xd_local_watch.node = NULL;
}
if (ivars->xd_node != NULL) {
free(ivars->xd_node, M_XENBUS);
ivars->xd_node = NULL;
}
ivars->xd_node_len = 0;
if (ivars->xd_type != NULL) {
free(ivars->xd_type, M_XENBUS);
ivars->xd_type = NULL;
}
if (ivars->xd_otherend_path != NULL) {
free(ivars->xd_otherend_path, M_XENBUS);
ivars->xd_otherend_path = NULL;
}
ivars->xd_otherend_path_len = 0;
free(ivars, M_XENBUS);
}
/**
* XenBus watch callback registered against the "state" XenStore
* node of the other-end of a split device connection.
*
* This callback is invoked whenever the state of a device instance's
* peer changes.
*
* \param watch The xs_watch object used to register this callback
* function.
* \param vec An array of pointers to NUL terminated strings containing
* watch event data. The vector should be indexed via the
* xs_watch_type enum in xs_wire.h.
* \param vec_size The number of elements in vec.
*/
static void
xenbusb_otherend_watch_cb(struct xs_watch *watch, const char **vec,
unsigned int vec_size __unused)
{
struct xenbus_device_ivars *ivars;
device_t child;
device_t bus;
const char *path;
enum xenbus_state newstate;
ivars = (struct xenbus_device_ivars *)watch->callback_data;
child = ivars->xd_dev;
bus = device_get_parent(child);
path = vec[XS_WATCH_PATH];
if (ivars->xd_otherend_path == NULL
|| strncmp(ivars->xd_otherend_path, path, ivars->xd_otherend_path_len))
return;
newstate = xenbus_read_driver_state(ivars->xd_otherend_path);
XENBUSB_OTHEREND_CHANGED(bus, child, newstate);
}
/**
* XenBus watch callback registered against the XenStore sub-tree
* represnting the local half of a split device connection.
*
* This callback is invoked whenever any XenStore data in the subtree
* is modified, either by us or another privledged domain.
*
* \param watch The xs_watch object used to register this callback
* function.
* \param vec An array of pointers to NUL terminated strings containing
* watch event data. The vector should be indexed via the
* xs_watch_type enum in xs_wire.h.
* \param vec_size The number of elements in vec.
*
*/
static void
xenbusb_local_watch_cb(struct xs_watch *watch, const char **vec,
unsigned int vec_size __unused)
{
struct xenbus_device_ivars *ivars;
device_t child;
device_t bus;
const char *path;
ivars = (struct xenbus_device_ivars *)watch->callback_data;
child = ivars->xd_dev;
bus = device_get_parent(child);
path = vec[XS_WATCH_PATH];
if (ivars->xd_node == NULL
|| strncmp(ivars->xd_node, path, ivars->xd_node_len))
return;
XENBUSB_LOCALEND_CHANGED(bus, child, &path[ivars->xd_node_len]);
}
/**
* Search our internal record of configured devices (not the XenStore)
* to determine if the XenBus device indicated by \a node is known to
* the system.
*
* \param dev The XenBus bus instance to search for device children.
* \param node The XenStore node path for the device to find.
*
* \return The device_t of the found device if any, or NULL.
*
* \note device_t is a pointer type, so it can be compared against
* NULL for validity.
*/
static device_t
xenbusb_device_exists(device_t dev, const char *node)
{
device_t *kids;
device_t result;
struct xenbus_device_ivars *ivars;
int i, count;
if (device_get_children(dev, &kids, &count))
return (FALSE);
result = NULL;
for (i = 0; i < count; i++) {
ivars = device_get_ivars(kids[i]);
if (!strcmp(ivars->xd_node, node)) {
result = kids[i];
break;
}
}
free(kids, M_TEMP);
return (result);
}
static void
xenbusb_delete_child(device_t dev, device_t child)
{
struct xenbus_device_ivars *ivars;
ivars = device_get_ivars(child);
/*
* We no longer care about the otherend of the
* connection. Cancel the watches now so that we
* don't try to handle an event for a partially
* detached child.
*/
if (ivars->xd_otherend_watch.node != NULL)
xs_unregister_watch(&ivars->xd_otherend_watch);
if (ivars->xd_local_watch.node != NULL)
xs_unregister_watch(&ivars->xd_local_watch);
device_delete_child(dev, child);
xenbusb_free_child_ivars(ivars);
}
/**
* \param dev The NewBus device representing this XenBus bus.
* \param child The NewBus device representing a child of dev%'s XenBus bus.
*/
static void
xenbusb_verify_device(device_t dev, device_t child)
{
if (xs_exists(XST_NIL, xenbus_get_node(child), "") == 0) {
/*
* Device tree has been removed from Xenbus.
* Tear down the device.
*/
xenbusb_delete_child(dev, child);
}
}
/**
* \brief Enumerate the devices on a XenBus bus and register them with
* the NewBus device tree.
*
* xenbusb_enumerate_bus() will create entries (in state DS_NOTPRESENT)
* for nodes that appear in the XenStore, but will not invoke probe/attach
* operations on drivers. Probe/Attach processing must be separately
* performed via an invocation of xenbusb_probe_children(). This is usually
* done via the xbs_probe_children task.
*
* \param xbs XenBus Bus device softc of the owner of the bus to enumerate.
*
* \return On success, 0. Otherwise an errno value indicating the
* type of failure.
*/
static int
xenbusb_enumerate_bus(struct xenbusb_softc *xbs)
{
const char **types;
u_int type_idx;
u_int type_count;
int error;
error = xs_directory(XST_NIL, xbs->xbs_node, "", &type_count, &types);
if (error)
return (error);
for (type_idx = 0; type_idx < type_count; type_idx++)
XENBUSB_ENUMERATE_TYPE(xbs->xbs_dev, types[type_idx]);
free(types, M_XENSTORE);
return (0);
}
/**
* Handler for all generic XenBus device systcl nodes.
*/
static int
xenbusb_device_sysctl_handler(SYSCTL_HANDLER_ARGS)
{
device_t dev;
const char *value;
dev = (device_t)arg1;
switch (arg2) {
case XENBUS_IVAR_NODE:
value = xenbus_get_node(dev);
break;
case XENBUS_IVAR_TYPE:
value = xenbus_get_type(dev);
break;
case XENBUS_IVAR_STATE:
value = xenbus_strstate(xenbus_get_state(dev));
break;
case XENBUS_IVAR_OTHEREND_ID:
return (sysctl_handle_int(oidp, NULL,
xenbus_get_otherend_id(dev),
req));
/* NOTREACHED */
case XENBUS_IVAR_OTHEREND_PATH:
value = xenbus_get_otherend_path(dev);
break;
default:
return (EINVAL);
}
return (SYSCTL_OUT_STR(req, value));
}
/**
* Create read-only systcl nodes for xenbusb device ivar data.
*
* \param dev The XenBus device instance to register with sysctl.
*/
static void
xenbusb_device_sysctl_init(device_t dev)
{
struct sysctl_ctx_list *ctx;
struct sysctl_oid *tree;
ctx = device_get_sysctl_ctx(dev);
tree = device_get_sysctl_tree(dev);
SYSCTL_ADD_PROC(ctx,
SYSCTL_CHILDREN(tree),
OID_AUTO,
"xenstore_path",
CTLTYPE_STRING | CTLFLAG_RD,
dev,
XENBUS_IVAR_NODE,
xenbusb_device_sysctl_handler,
"A",
"XenStore path to device");
SYSCTL_ADD_PROC(ctx,
SYSCTL_CHILDREN(tree),
OID_AUTO,
"xenbus_dev_type",
CTLTYPE_STRING | CTLFLAG_RD,
dev,
XENBUS_IVAR_TYPE,
xenbusb_device_sysctl_handler,
"A",
"XenBus device type");
SYSCTL_ADD_PROC(ctx,
SYSCTL_CHILDREN(tree),
OID_AUTO,
"xenbus_connection_state",
CTLTYPE_STRING | CTLFLAG_RD,
dev,
XENBUS_IVAR_STATE,
xenbusb_device_sysctl_handler,
"A",
"XenBus state of peer connection");
SYSCTL_ADD_PROC(ctx,
SYSCTL_CHILDREN(tree),
OID_AUTO,
"xenbus_peer_domid",
CTLTYPE_INT | CTLFLAG_RD,
dev,
XENBUS_IVAR_OTHEREND_ID,
xenbusb_device_sysctl_handler,
"I",
"Xen domain ID of peer");
SYSCTL_ADD_PROC(ctx,
SYSCTL_CHILDREN(tree),
OID_AUTO,
"xenstore_peer_path",
CTLTYPE_STRING | CTLFLAG_RD,
dev,
XENBUS_IVAR_OTHEREND_PATH,
xenbusb_device_sysctl_handler,
"A",
"XenStore path to peer device");
}
/**
* \brief Decrement the number of XenBus child devices in the
* connecting state by one and release the xbs_attch_ch
* interrupt configuration hook if the connecting count
* drops to zero.
*
* \param xbs XenBus Bus device softc of the owner of the bus to enumerate.
*/
static void
xenbusb_release_confighook(struct xenbusb_softc *xbs)
{
mtx_lock(&xbs->xbs_lock);
KASSERT(xbs->xbs_connecting_children > 0,
("Connecting device count error\n"));
xbs->xbs_connecting_children--;
if (xbs->xbs_connecting_children == 0
&& (xbs->xbs_flags & XBS_ATTACH_CH_ACTIVE) != 0) {
xbs->xbs_flags &= ~XBS_ATTACH_CH_ACTIVE;
mtx_unlock(&xbs->xbs_lock);
config_intrhook_disestablish(&xbs->xbs_attach_ch);
} else {
mtx_unlock(&xbs->xbs_lock);
}
}
/**
* \brief Verify the existance of attached device instances and perform
* probe/attach processing for newly arrived devices.
*
* \param dev The NewBus device representing this XenBus bus.
*
* \return On success, 0. Otherwise an errno value indicating the
* type of failure.
*/
static int
xenbusb_probe_children(device_t dev)
{
device_t *kids;
struct xenbus_device_ivars *ivars;
int i, count, error;
if (device_get_children(dev, &kids, &count) == 0) {
for (i = 0; i < count; i++) {
if (device_get_state(kids[i]) != DS_NOTPRESENT) {
/*
* We already know about this one.
* Make sure it's still here.
*/
xenbusb_verify_device(dev, kids[i]);
continue;
}
error = device_probe_and_attach(kids[i]);
if (error == ENXIO) {
struct xenbusb_softc *xbs;
/*
* We don't have a PV driver for this device.
* However, an emulated device we do support
* may share this backend. Hide the node from
* XenBus until the next rescan, but leave it's
* state unchanged so we don't inadvertently
* prevent attachment of any emulated device.
*/
xenbusb_delete_child(dev, kids[i]);
/*
* Since the XenStore state of this device
* still indicates a pending attach, manually
* release it's hold on the boot process.
*/
xbs = device_get_softc(dev);
xenbusb_release_confighook(xbs);
continue;
} else if (error) {
/*
* Transition device to the closed state
* so the world knows that attachment will
* not occur.
*/
xenbus_set_state(kids[i], XenbusStateClosed);
/*
* Remove our record of this device.
* So long as it remains in the closed
* state in the XenStore, we will not find
* it again. The state will only change
* if the control domain actively reconfigures
* this device.
*/
xenbusb_delete_child(dev, kids[i]);
continue;
}
/*
* Augment default newbus provided dynamic sysctl
* variables with the standard ivar contents of
* XenBus devices.
*/
xenbusb_device_sysctl_init(kids[i]);
/*
* Now that we have a driver managing this device
* that can receive otherend state change events,
* hook up a watch for them.
*/
ivars = device_get_ivars(kids[i]);
xs_register_watch(&ivars->xd_otherend_watch);
xs_register_watch(&ivars->xd_local_watch);
}
free(kids, M_TEMP);
}
return (0);
}
/**
* \brief Task callback function to perform XenBus probe operations
* from a known safe context.
*
* \param arg The NewBus device_t representing the bus instance to
* on which to perform probe processing.
* \param pending The number of times this task was queued before it could
* be run.
*/
static void
xenbusb_probe_children_cb(void *arg, int pending __unused)
{
device_t dev = (device_t)arg;
/*
* Hold Giant until the Giant free newbus changes are committed.
*/
mtx_lock(&Giant);
xenbusb_probe_children(dev);
mtx_unlock(&Giant);
}
/**
* \brief XenStore watch callback for the root node of the XenStore
* subtree representing a XenBus.
*
* This callback performs, or delegates to the xbs_probe_children task,
* all processing necessary to handle dynmaic device arrival and departure
* events from a XenBus.
*
* \param watch The XenStore watch object associated with this callback.
* \param vec The XenStore watch event data.
* \param len The number of fields in the event data stream.
*/
static void
xenbusb_devices_changed(struct xs_watch *watch, const char **vec,
unsigned int len)
{
struct xenbusb_softc *xbs;
device_t dev;
char *node;
char *bus;
char *type;
char *id;
char *p;
u_int component;
xbs = (struct xenbusb_softc *)watch->callback_data;
dev = xbs->xbs_dev;
if (len <= XS_WATCH_PATH) {
device_printf(dev, "xenbusb_devices_changed: "
"Short Event Data.\n");
return;
}
node = strdup(vec[XS_WATCH_PATH], M_XENBUS);
p = strchr(node, '/');
if (p == NULL)
goto out;
bus = node;
*p = 0;
type = p + 1;
p = strchr(type, '/');
if (p == NULL)
goto out;
*p++ = 0;
/*
* Extract the device ID. A device ID has one or more path
* components separated by the '/' character.
*
* e.g. "<frontend vm id>/<frontend dev id>" for backend devices.
*/
id = p;
for (component = 0; component < xbs->xbs_id_components; component++) {
p = strchr(p, '/');
if (p == NULL)
break;
p++;
}
if (p != NULL)
*p = 0;
if (*id != 0 && component >= xbs->xbs_id_components - 1) {
xenbusb_add_device(xbs->xbs_dev, type, id);
taskqueue_enqueue(taskqueue_thread, &xbs->xbs_probe_children);
}
out:
free(node, M_XENBUS);
}
/**
* \brief Interrupt configuration hook callback associated with xbs_attch_ch.
*
* Since interrupts are always functional at the time of XenBus configuration,
* there is nothing to be done when the callback occurs. This hook is only
* registered to hold up boot processing while XenBus devices come online.
*
* \param arg Unused configuration hook callback argument.
*/
static void
xenbusb_nop_confighook_cb(void *arg __unused)
{
}
/*--------------------------- Public Functions -------------------------------*/
/*--------- API comments for these methods can be found in xenbusb.h ---------*/
void
xenbusb_identify(driver_t *driver __unused, device_t parent)
{
/*
* A single instance of each bus type for which we have a driver
* is always present in a system operating under Xen.
*/
BUS_ADD_CHILD(parent, 0, driver->name, 0);
}
int
xenbusb_add_device(device_t dev, const char *type, const char *id)
{
struct xenbusb_softc *xbs;
struct sbuf *devpath_sbuf;
char *devpath;
struct xenbus_device_ivars *ivars;
int error;
xbs = device_get_softc(dev);
devpath_sbuf = sbuf_new_auto();
sbuf_printf(devpath_sbuf, "%s/%s/%s", xbs->xbs_node, type, id);
sbuf_finish(devpath_sbuf);
devpath = sbuf_data(devpath_sbuf);
ivars = malloc(sizeof(*ivars), M_XENBUS, M_ZERO|M_WAITOK);
error = ENXIO;
if (xs_exists(XST_NIL, devpath, "") != 0) {
device_t child;
enum xenbus_state state;
char *statepath;
child = xenbusb_device_exists(dev, devpath);
if (child != NULL) {
/*
* We are already tracking this node
*/
error = 0;
goto out;
}
state = xenbus_read_driver_state(devpath);
if (state != XenbusStateInitialising) {
/*
* Device is not new, so ignore it. This can
* happen if a device is going away after
* switching to Closed.
*/
printf("xenbusb_add_device: Device %s ignored. "
"State %d\n", devpath, state);
error = 0;
goto out;
}
sx_init(&ivars->xd_lock, "xdlock");
ivars->xd_flags = XDF_CONNECTING;
ivars->xd_node = strdup(devpath, M_XENBUS);
ivars->xd_node_len = strlen(devpath);
ivars->xd_type = strdup(type, M_XENBUS);
ivars->xd_state = XenbusStateInitialising;
error = XENBUSB_GET_OTHEREND_NODE(dev, ivars);
if (error) {
printf("xenbus_update_device: %s no otherend id\n",
devpath);
goto out;
}
statepath = malloc(ivars->xd_otherend_path_len
+ strlen("/state") + 1, M_XENBUS, M_WAITOK);
sprintf(statepath, "%s/state", ivars->xd_otherend_path);
ivars->xd_otherend_watch.node = statepath;
ivars->xd_otherend_watch.callback = xenbusb_otherend_watch_cb;
ivars->xd_otherend_watch.callback_data = (uintptr_t)ivars;
ivars->xd_local_watch.node = ivars->xd_node;
ivars->xd_local_watch.callback = xenbusb_local_watch_cb;
ivars->xd_local_watch.callback_data = (uintptr_t)ivars;
mtx_lock(&xbs->xbs_lock);
xbs->xbs_connecting_children++;
mtx_unlock(&xbs->xbs_lock);
child = device_add_child(dev, NULL, -1);
ivars->xd_dev = child;
device_set_ivars(child, ivars);
}
out:
sbuf_delete(devpath_sbuf);
if (error != 0)
xenbusb_free_child_ivars(ivars);
return (error);
}
int
xenbusb_attach(device_t dev, char *bus_node, u_int id_components)
{
struct xenbusb_softc *xbs;
xbs = device_get_softc(dev);
mtx_init(&xbs->xbs_lock, "xenbusb softc lock", NULL, MTX_DEF);
xbs->xbs_node = bus_node;
xbs->xbs_id_components = id_components;
xbs->xbs_dev = dev;
/*
* Since XenBus busses are attached to the XenStore, and
* the XenStore does not probe children until after interrupt
* services are available, this config hook is used solely
* to ensure that the remainder of the boot process (e.g.
* mount root) is deferred until child devices are adequately
* probed. We unblock the boot process as soon as the
* connecting child count in our softc goes to 0.
*/
xbs->xbs_attach_ch.ich_func = xenbusb_nop_confighook_cb;
xbs->xbs_attach_ch.ich_arg = dev;
config_intrhook_establish(&xbs->xbs_attach_ch);
xbs->xbs_flags |= XBS_ATTACH_CH_ACTIVE;
xbs->xbs_connecting_children = 1;
/*
* The subtree for this bus type may not yet exist
* causing initial enumeration to fail. We still
* want to return success from our attach though
* so that we are ready to handle devices for this
* bus when they are dynamically attached to us
* by a Xen management action.
*/
(void)xenbusb_enumerate_bus(xbs);
xenbusb_probe_children(dev);
xbs->xbs_device_watch.node = bus_node;
xbs->xbs_device_watch.callback = xenbusb_devices_changed;
xbs->xbs_device_watch.callback_data = (uintptr_t)xbs;
TASK_INIT(&xbs->xbs_probe_children, 0, xenbusb_probe_children_cb, dev);
xs_register_watch(&xbs->xbs_device_watch);
xenbusb_release_confighook(xbs);
return (0);
}
int
xenbusb_resume(device_t dev)
{
device_t *kids;
struct xenbus_device_ivars *ivars;
int i, count, error;
char *statepath;
/*
* We must re-examine each device and find the new path for
* its backend.
*/
if (device_get_children(dev, &kids, &count) == 0) {
for (i = 0; i < count; i++) {
if (device_get_state(kids[i]) == DS_NOTPRESENT)
continue;
ivars = device_get_ivars(kids[i]);
xs_unregister_watch(&ivars->xd_otherend_watch);
xenbus_set_state(kids[i], XenbusStateInitialising);
/*
* Find the new backend details and
* re-register our watch.
*/
error = XENBUSB_GET_OTHEREND_NODE(dev, ivars);
if (error)
return (error);
statepath = malloc(ivars->xd_otherend_path_len
+ strlen("/state") + 1, M_XENBUS, M_WAITOK);
sprintf(statepath, "%s/state", ivars->xd_otherend_path);
free(ivars->xd_otherend_watch.node, M_XENBUS);
ivars->xd_otherend_watch.node = statepath;
DEVICE_RESUME(kids[i]);
xs_register_watch(&ivars->xd_otherend_watch);
#if 0
/*
* Can't do this yet since we are running in
* the xenwatch thread and if we sleep here,
* we will stop delivering watch notifications
* and the device will never come back online.
*/
sx_xlock(&ivars->xd_lock);
while (ivars->xd_state != XenbusStateClosed
&& ivars->xd_state != XenbusStateConnected)
sx_sleep(&ivars->xd_state, &ivars->xd_lock,
0, "xdresume", 0);
sx_xunlock(&ivars->xd_lock);
#endif
}
free(kids, M_TEMP);
}
return (0);
}
int
xenbusb_print_child(device_t dev, device_t child)
{
struct xenbus_device_ivars *ivars = device_get_ivars(child);
int retval = 0;
retval += bus_print_child_header(dev, child);
retval += printf(" at %s", ivars->xd_node);
retval += bus_print_child_footer(dev, child);
return (retval);
}
int
xenbusb_read_ivar(device_t dev, device_t child, int index, uintptr_t *result)
{
struct xenbus_device_ivars *ivars = device_get_ivars(child);
switch (index) {
case XENBUS_IVAR_NODE:
*result = (uintptr_t) ivars->xd_node;
return (0);
case XENBUS_IVAR_TYPE:
*result = (uintptr_t) ivars->xd_type;
return (0);
case XENBUS_IVAR_STATE:
*result = (uintptr_t) ivars->xd_state;
return (0);
case XENBUS_IVAR_OTHEREND_ID:
*result = (uintptr_t) ivars->xd_otherend_id;
return (0);
case XENBUS_IVAR_OTHEREND_PATH:
*result = (uintptr_t) ivars->xd_otherend_path;
return (0);
}
return (ENOENT);
}
int
xenbusb_write_ivar(device_t dev, device_t child, int index, uintptr_t value)
{
struct xenbus_device_ivars *ivars = device_get_ivars(child);
enum xenbus_state newstate;
int currstate;
switch (index) {
case XENBUS_IVAR_STATE:
{
int error;
newstate = (enum xenbus_state)value;
sx_xlock(&ivars->xd_lock);
if (ivars->xd_state == newstate) {
error = 0;
goto out;
}
error = xs_scanf(XST_NIL, ivars->xd_node, "state",
NULL, "%d", &currstate);
if (error)
goto out;
do {
error = xs_printf(XST_NIL, ivars->xd_node, "state",
"%d", newstate);
} while (error == EAGAIN);
if (error) {
/*
* Avoid looping through xenbus_dev_fatal()
* which calls xenbus_write_ivar to set the
* state to closing.
*/
if (newstate != XenbusStateClosing)
xenbus_dev_fatal(dev, error,
"writing new state");
goto out;
}
ivars->xd_state = newstate;
if ((ivars->xd_flags & XDF_CONNECTING) != 0
&& (newstate == XenbusStateClosed
|| newstate == XenbusStateConnected)) {
struct xenbusb_softc *xbs;
ivars->xd_flags &= ~XDF_CONNECTING;
xbs = device_get_softc(dev);
xenbusb_release_confighook(xbs);
}
wakeup(&ivars->xd_state);
out:
sx_xunlock(&ivars->xd_lock);
return (error);
}
case XENBUS_IVAR_NODE:
case XENBUS_IVAR_TYPE:
case XENBUS_IVAR_OTHEREND_ID:
case XENBUS_IVAR_OTHEREND_PATH:
/*
* These variables are read-only.
*/
return (EINVAL);
}
return (ENOENT);
}
void
xenbusb_otherend_changed(device_t bus, device_t child, enum xenbus_state state)
{
XENBUS_OTHEREND_CHANGED(child, state);
}
void
xenbusb_localend_changed(device_t bus, device_t child, const char *path)
{
if (strcmp(path, "/state") != 0) {
struct xenbus_device_ivars *ivars;
ivars = device_get_ivars(child);
sx_xlock(&ivars->xd_lock);
ivars->xd_state = xenbus_read_driver_state(ivars->xd_node);
sx_xunlock(&ivars->xd_lock);
}
XENBUS_LOCALEND_CHANGED(child, path);
}
