--- /dev/null
+/* Xenbus code for tpmif backend
+ Copyright (C) 2005 IBM Corporation
+ Copyright (C) 2005 Rusty Russell <rusty@rustcorp.com.au>
+
+ This program is free software; you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation; either version 2 of the License, or
+ (at your option) any later version.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with this program; if not, write to the Free Software
+ Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+*/
+#include <stdarg.h>
+#include <linux/module.h>
+#include <xen/xenbus.h>
+#include "common.h"
+
+struct backend_info
+{
+ struct xenbus_device *dev;
+
+ /* our communications channel */
+ tpmif_t *tpmif;
+
+ long int frontend_id;
+ long int instance; // instance of TPM
+ u8 is_instance_set;// whether instance number has been set
+
+ /* watch front end for changes */
+ struct xenbus_watch backend_watch;
+ enum xenbus_state frontend_state;
+};
+
+static void maybe_connect(struct backend_info *be);
+static void connect(struct backend_info *be);
+static int connect_ring(struct backend_info *be);
+static void backend_changed(struct xenbus_watch *watch,
+ const char **vec, unsigned int len);
+static void frontend_changed(struct xenbus_device *dev,
+ enum xenbus_state frontend_state);
+
+long int tpmback_get_instance(struct backend_info *bi)
+{
+ long int res = -1;
+ if (bi && bi->is_instance_set)
+ res = bi->instance;
+ return res;
+}
+
+static int tpmback_remove(struct xenbus_device *dev)
+{
+ struct backend_info *be = dev->dev.driver_data;
+
+ if (!be) return 0;
+
+ if (be->backend_watch.node) {
+ unregister_xenbus_watch(&be->backend_watch);
+ kfree(be->backend_watch.node);
+ be->backend_watch.node = NULL;
+ }
+ if (be->tpmif) {
+ be->tpmif->bi = NULL;
+ vtpm_release_packets(be->tpmif, 0);
+ tpmif_put(be->tpmif);
+ be->tpmif = NULL;
+ }
+ kfree(be);
+ dev->dev.driver_data = NULL;
+ return 0;
+}
+
+static int tpmback_probe(struct xenbus_device *dev,
+ const struct xenbus_device_id *id)
+{
+ int err;
+ struct backend_info *be = kzalloc(sizeof(struct backend_info),
+ GFP_KERNEL);
+
+ if (!be) {
+ xenbus_dev_fatal(dev, -ENOMEM,
+ "allocating backend structure");
+ return -ENOMEM;
+ }
+
+ be->is_instance_set = 0;
+ be->dev = dev;
+ dev->dev.driver_data = be;
+
+ err = xenbus_watch_path2(dev, dev->nodename,
+ "instance", &be->backend_watch,
+ backend_changed);
+ if (err) {
+ goto fail;
+ }
+
+ err = xenbus_switch_state(dev, XenbusStateInitWait);
+ if (err) {
+ goto fail;
+ }
+ return 0;
+fail:
+ tpmback_remove(dev);
+ return err;
+}
+
+
+static void backend_changed(struct xenbus_watch *watch,
+ const char **vec, unsigned int len)
+{
+ int err;
+ long instance;
+ struct backend_info *be
+ = container_of(watch, struct backend_info, backend_watch);
+ struct xenbus_device *dev = be->dev;
+
+ err = xenbus_scanf(XBT_NIL, dev->nodename,
+ "instance","%li", &instance);
+ if (XENBUS_EXIST_ERR(err)) {
+ return;
+ }
+
+ if (err != 1) {
+ xenbus_dev_fatal(dev, err, "reading instance");
+ return;
+ }
+
+ if (be->is_instance_set == 0) {
+ be->instance = instance;
+ be->is_instance_set = 1;
+ }
+}
+
+
+static void frontend_changed(struct xenbus_device *dev,
+ enum xenbus_state frontend_state)
+{
+ struct backend_info *be = dev->dev.driver_data;
+ int err;
+
+ be->frontend_state = frontend_state;
+
+ switch (frontend_state) {
+ case XenbusStateInitialising:
+ case XenbusStateInitialised:
+ break;
+
+ case XenbusStateConnected:
+ err = connect_ring(be);
+ if (err) {
+ return;
+ }
+ maybe_connect(be);
+ break;
+
+ case XenbusStateClosing:
+ be->instance = -1;
+ break;
+
+ case XenbusStateClosed:
+ device_unregister(&be->dev->dev);
+ tpmback_remove(dev);
+ break;
+
+ case XenbusStateUnknown:
+ case XenbusStateInitWait:
+ default:
+ xenbus_dev_fatal(dev, -EINVAL,
+ "saw state %d at frontend",
+ frontend_state);
+ break;
+ }
+}
+
+
+
+static void maybe_connect(struct backend_info *be)
+{
+ if (be->tpmif == NULL || be->tpmif->status == CONNECTED)
+ return;
+
+ connect(be);
+}
+
+
+static void connect(struct backend_info *be)
+{
+ struct xenbus_transaction xbt;
+ int err;
+ struct xenbus_device *dev = be->dev;
+ unsigned long ready = 1;
+
+again:
+ err = xenbus_transaction_start(&xbt);
+ if (err) {
+ xenbus_dev_fatal(be->dev, err, "starting transaction");
+ return;
+ }
+
+ err = xenbus_printf(xbt, be->dev->nodename,
+ "ready", "%lu", ready);
+ if (err) {
+ xenbus_dev_fatal(be->dev, err, "writing 'ready'");
+ goto abort;
+ }
+
+ err = xenbus_transaction_end(xbt, 0);
+ if (err == -EAGAIN)
+ goto again;
+ if (err)
+ xenbus_dev_fatal(be->dev, err, "end of transaction");
+
+ err = xenbus_switch_state(dev, XenbusStateConnected);
+ if (!err)
+ be->tpmif->status = CONNECTED;
+ return;
+abort:
+ xenbus_transaction_end(xbt, 1);
+}
+
+
+static int connect_ring(struct backend_info *be)
+{
+ struct xenbus_device *dev = be->dev;
+ unsigned long ring_ref;
+ unsigned int evtchn;
+ int err;
+
+ err = xenbus_gather(XBT_NIL, dev->otherend,
+ "ring-ref", "%lu", &ring_ref,
+ "event-channel", "%u", &evtchn, NULL);
+ if (err) {
+ xenbus_dev_error(dev, err,
+ "reading %s/ring-ref and event-channel",
+ dev->otherend);
+ return err;
+ }
+
+ if (!be->tpmif) {
+ be->tpmif = tpmif_find(dev->otherend_id, be);
+ if (IS_ERR(be->tpmif)) {
+ err = PTR_ERR(be->tpmif);
+ be->tpmif = NULL;
+ xenbus_dev_fatal(dev,err,"creating vtpm interface");
+ return err;
+ }
+ }
+
+ if (be->tpmif != NULL) {
+ err = tpmif_map(be->tpmif, ring_ref, evtchn);
+ if (err) {
+ xenbus_dev_error(dev, err,
+ "mapping shared-frame %lu port %u",
+ ring_ref, evtchn);
+ return err;
+ }
+ }
+ return 0;
+}
+
+
+static struct xenbus_device_id tpmback_ids[] = {
+ { "vtpm" },
+ { "" }
+};
+
+
+static struct xenbus_driver tpmback = {
+ .name = "vtpm",
+ .owner = THIS_MODULE,
+ .ids = tpmback_ids,
+ .probe = tpmback_probe,
+ .remove = tpmback_remove,
+ .otherend_changed = frontend_changed,
+};
+
+
+void tpmif_xenbus_init(void)
+{
+ xenbus_register_backend(&tpmback);
+}
+
+void tpmif_xenbus_exit(void)
+{
+ xenbus_unregister_driver(&tpmback);
+}
git://git.onelab.eu / linux-2.6.git / blobdiff