[mirror_ubuntu-bionic-kernel.git] / drivers / char / tpm / xen-tpmfront.c

/*
 * Implementation of the Xen vTPM device frontend
 *
 * Author:  Daniel De Graaf <dgdegra@tycho.nsa.gov>
 *
 * 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.
 */
#include <linux/errno.h>
#include <linux/err.h>
#include <linux/interrupt.h>
#include <xen/xen.h>
#include <xen/events.h>
#include <xen/interface/io/tpmif.h>
#include <xen/grant_table.h>
#include <xen/xenbus.h>
#include <xen/page.h>
#include "tpm.h"
#include <xen/platform_pci.h>

struct tpm_private {
	struct tpm_chip *chip;
	struct xenbus_device *dev;

	struct vtpm_shared_page *shr;

	unsigned int evtchn;
	int ring_ref;
	domid_t backend_id;
	int irq;
	wait_queue_head_t read_queue;
};

enum status_bits {
	VTPM_STATUS_RUNNING  = 0x1,
	VTPM_STATUS_IDLE     = 0x2,
	VTPM_STATUS_RESULT   = 0x4,
	VTPM_STATUS_CANCELED = 0x8,
};

static u8 vtpm_status(struct tpm_chip *chip)
{
	struct tpm_private *priv = dev_get_drvdata(&chip->dev);
	switch (priv->shr->state) {
	case VTPM_STATE_IDLE:
		return VTPM_STATUS_IDLE | VTPM_STATUS_CANCELED;
	case VTPM_STATE_FINISH:
		return VTPM_STATUS_IDLE | VTPM_STATUS_RESULT;
	case VTPM_STATE_SUBMIT:
	case VTPM_STATE_CANCEL: /* cancel requested, not yet canceled */
		return VTPM_STATUS_RUNNING;
	default:
		return 0;
	}
}

static bool vtpm_req_canceled(struct tpm_chip *chip, u8 status)
{
	return status & VTPM_STATUS_CANCELED;
}

static void vtpm_cancel(struct tpm_chip *chip)
{
	struct tpm_private *priv = dev_get_drvdata(&chip->dev);
	priv->shr->state = VTPM_STATE_CANCEL;
	wmb();
	notify_remote_via_evtchn(priv->evtchn);
}

static unsigned int shr_data_offset(struct vtpm_shared_page *shr)
{
	return sizeof(*shr) + sizeof(u32) * shr->nr_extra_pages;
}

static int vtpm_send(struct tpm_chip *chip, u8 *buf, size_t count)
{
	struct tpm_private *priv = dev_get_drvdata(&chip->dev);
	struct vtpm_shared_page *shr = priv->shr;
	unsigned int offset = shr_data_offset(shr);

	u32 ordinal;
	unsigned long duration;

	if (offset > PAGE_SIZE)
		return -EINVAL;

	if (offset + count > PAGE_SIZE)
		return -EINVAL;

	/* Wait for completion of any existing command or cancellation */
	if (wait_for_tpm_stat(chip, VTPM_STATUS_IDLE, chip->timeout_c,
			&priv->read_queue, true) < 0) {
		vtpm_cancel(chip);
		return -ETIME;
	}

	memcpy(offset + (u8 *)shr, buf, count);
	shr->length = count;
	barrier();
	shr->state = VTPM_STATE_SUBMIT;
	wmb();
	notify_remote_via_evtchn(priv->evtchn);

	ordinal = be32_to_cpu(((struct tpm_input_header*)buf)->ordinal);
	duration = tpm_calc_ordinal_duration(chip, ordinal);

	if (wait_for_tpm_stat(chip, VTPM_STATUS_IDLE, duration,
			&priv->read_queue, true) < 0) {
		/* got a signal or timeout, try to cancel */
		vtpm_cancel(chip);
		return -ETIME;
	}

	return 0;
}

static int vtpm_recv(struct tpm_chip *chip, u8 *buf, size_t count)
{
	struct tpm_private *priv = dev_get_drvdata(&chip->dev);
	struct vtpm_shared_page *shr = priv->shr;
	unsigned int offset = shr_data_offset(shr);
	size_t length = shr->length;

	if (shr->state == VTPM_STATE_IDLE)
		return -ECANCELED;

	/* In theory the wait at the end of _send makes this one unnecessary */
	if (wait_for_tpm_stat(chip, VTPM_STATUS_RESULT, chip->timeout_c,
			&priv->read_queue, true) < 0) {
		vtpm_cancel(chip);
		return -ETIME;
	}

	if (offset > PAGE_SIZE)
		return -EIO;

	if (offset + length > PAGE_SIZE)
		length = PAGE_SIZE - offset;

	if (length > count)
		length = count;

	memcpy(buf, offset + (u8 *)shr, length);

	return length;
}

static const struct tpm_class_ops tpm_vtpm = {
	.status = vtpm_status,
	.recv = vtpm_recv,
	.send = vtpm_send,
	.cancel = vtpm_cancel,
	.req_complete_mask = VTPM_STATUS_IDLE | VTPM_STATUS_RESULT,
	.req_complete_val  = VTPM_STATUS_IDLE | VTPM_STATUS_RESULT,
	.req_canceled      = vtpm_req_canceled,
};

static irqreturn_t tpmif_interrupt(int dummy, void *dev_id)
{
	struct tpm_private *priv = dev_id;

	switch (priv->shr->state) {
	case VTPM_STATE_IDLE:
	case VTPM_STATE_FINISH:
		wake_up_interruptible(&priv->read_queue);
		break;
	case VTPM_STATE_SUBMIT:
	case VTPM_STATE_CANCEL:
	default:
		break;
	}
	return IRQ_HANDLED;
}

static int setup_chip(struct device *dev, struct tpm_private *priv)
{
	struct tpm_chip *chip;

	chip = tpmm_chip_alloc(dev, &tpm_vtpm);
	if (IS_ERR(chip))
		return PTR_ERR(chip);

	init_waitqueue_head(&priv->read_queue);

	priv->chip = chip;
	dev_set_drvdata(&chip->dev, priv);

	return 0;
}

/* caller must clean up in case of errors */
static int setup_ring(struct xenbus_device *dev, struct tpm_private *priv)
{
	struct xenbus_transaction xbt;
	const char *message = NULL;
	int rv;
	grant_ref_t gref;

	priv->shr = (void *)__get_free_page(GFP_KERNEL|__GFP_ZERO);
	if (!priv->shr) {
		xenbus_dev_fatal(dev, -ENOMEM, "allocating shared ring");
		return -ENOMEM;
	}

	rv = xenbus_grant_ring(dev, priv->shr, 1, &gref);
	if (rv < 0)
		return rv;

	priv->ring_ref = gref;

	rv = xenbus_alloc_evtchn(dev, &priv->evtchn);
	if (rv)
		return rv;

	rv = bind_evtchn_to_irqhandler(priv->evtchn, tpmif_interrupt, 0,
				       "tpmif", priv);
	if (rv <= 0) {
		xenbus_dev_fatal(dev, rv, "allocating TPM irq");
		return rv;
	}
	priv->irq = rv;

 again:
	rv = xenbus_transaction_start(&xbt);
	if (rv) {
		xenbus_dev_fatal(dev, rv, "starting transaction");
		return rv;
	}

	rv = xenbus_printf(xbt, dev->nodename,
			"ring-ref", "%u", priv->ring_ref);
	if (rv) {
		message = "writing ring-ref";
		goto abort_transaction;
	}

	rv = xenbus_printf(xbt, dev->nodename, "event-channel", "%u",
			priv->evtchn);
	if (rv) {
		message = "writing event-channel";
		goto abort_transaction;
	}

	rv = xenbus_printf(xbt, dev->nodename, "feature-protocol-v2", "1");
	if (rv) {
		message = "writing feature-protocol-v2";
		goto abort_transaction;
	}

	rv = xenbus_transaction_end(xbt, 0);
	if (rv == -EAGAIN)
		goto again;
	if (rv) {
		xenbus_dev_fatal(dev, rv, "completing transaction");
		return rv;
	}

	xenbus_switch_state(dev, XenbusStateInitialised);

	return 0;

 abort_transaction:
	xenbus_transaction_end(xbt, 1);
	if (message)
		xenbus_dev_error(dev, rv, "%s", message);

	return rv;
}

static void ring_free(struct tpm_private *priv)
{
	if (!priv)
		return;

	if (priv->ring_ref)
		gnttab_end_foreign_access(priv->ring_ref, 0,
				(unsigned long)priv->shr);
	else
		free_page((unsigned long)priv->shr);

	if (priv->irq)
		unbind_from_irqhandler(priv->irq, priv);

	kfree(priv);
}

static int tpmfront_probe(struct xenbus_device *dev,
		const struct xenbus_device_id *id)
{
	struct tpm_private *priv;
	int rv;

	priv = kzalloc(sizeof(*priv), GFP_KERNEL);
	if (!priv) {
		xenbus_dev_fatal(dev, -ENOMEM, "allocating priv structure");
		return -ENOMEM;
	}

	rv = setup_chip(&dev->dev, priv);
	if (rv) {
		kfree(priv);
		return rv;
	}

	rv = setup_ring(dev, priv);
	if (rv) {
		ring_free(priv);
		return rv;
	}

	tpm_get_timeouts(priv->chip);

	return tpm_chip_register(priv->chip);
}

static int tpmfront_remove(struct xenbus_device *dev)
{
	struct tpm_chip *chip = dev_get_drvdata(&dev->dev);
	struct tpm_private *priv = dev_get_drvdata(&chip->dev);
	tpm_chip_unregister(chip);
	ring_free(priv);
	dev_set_drvdata(&chip->dev, NULL);
	return 0;
}

static int tpmfront_resume(struct xenbus_device *dev)
{
	/* A suspend/resume/migrate will interrupt a vTPM anyway */
	tpmfront_remove(dev);
	return tpmfront_probe(dev, NULL);
}

static void backend_changed(struct xenbus_device *dev,
		enum xenbus_state backend_state)
{
	switch (backend_state) {
	case XenbusStateInitialised:
	case XenbusStateConnected:
		if (dev->state == XenbusStateConnected)
			break;

		if (!xenbus_read_unsigned(dev->otherend, "feature-protocol-v2",
					  0)) {
			xenbus_dev_fatal(dev, -EINVAL,
					"vTPM protocol 2 required");
			return;
		}
		xenbus_switch_state(dev, XenbusStateConnected);
		break;

	case XenbusStateClosing:
	case XenbusStateClosed:
		device_unregister(&dev->dev);
		xenbus_frontend_closed(dev);
		break;
	default:
		break;
	}
}

static const struct xenbus_device_id tpmfront_ids[] = {
	{ "vtpm" },
	{ "" }
};
MODULE_ALIAS("xen:vtpm");

static struct xenbus_driver tpmfront_driver = {
	.ids = tpmfront_ids,
	.probe = tpmfront_probe,
	.remove = tpmfront_remove,
	.resume = tpmfront_resume,
	.otherend_changed = backend_changed,
};

static int __init xen_tpmfront_init(void)
{
	if (!xen_domain())
		return -ENODEV;

	if (!xen_has_pv_devices())
		return -ENODEV;

	return xenbus_register_frontend(&tpmfront_driver);
}
module_init(xen_tpmfront_init);

static void __exit xen_tpmfront_exit(void)
{
	xenbus_unregister_driver(&tpmfront_driver);
}
module_exit(xen_tpmfront_exit);

MODULE_AUTHOR("Daniel De Graaf <dgdegra@tycho.nsa.gov>");
MODULE_DESCRIPTION("Xen vTPM Driver");
MODULE_LICENSE("GPL");
Commit	Line	Data
e2683957 DDG	1	/*
	2	* Implementation of the Xen vTPM device frontend
	3	*
	4	* Author: Daniel De Graaf <dgdegra@tycho.nsa.gov>
	5	*
	6	* This program is free software; you can redistribute it and/or modify
	7	* it under the terms of the GNU General Public License version 2,
	8	* as published by the Free Software Foundation.
	9	*/
	10	#include <linux/errno.h>
	11	#include <linux/err.h>
	12	#include <linux/interrupt.h>
8702c675	13	#include <xen/xen.h>
e2683957 DDG	14	#include <xen/events.h>
	15	#include <xen/interface/io/tpmif.h>
	16	#include <xen/grant_table.h>
	17	#include <xen/xenbus.h>
	18	#include <xen/page.h>
	19	#include "tpm.h"
51c71a3b	20	#include <xen/platform_pci.h>
e2683957 DDG	21
	22	struct tpm_private {
	23	struct tpm_chip *chip;
	24	struct xenbus_device *dev;
	25
	26	struct vtpm_shared_page *shr;
	27
	28	unsigned int evtchn;
	29	int ring_ref;
	30	domid_t backend_id;
570a3609	31	int irq;
6e599f6f	32	wait_queue_head_t read_queue;
e2683957 DDG	33	};
	34
	35	enum status_bits {
	36	VTPM_STATUS_RUNNING = 0x1,
	37	VTPM_STATUS_IDLE = 0x2,
	38	VTPM_STATUS_RESULT = 0x4,
	39	VTPM_STATUS_CANCELED = 0x8,
	40	};
	41
	42	static u8 vtpm_status(struct tpm_chip *chip)
	43	{
9e0d39d8	44	struct tpm_private *priv = dev_get_drvdata(&chip->dev);
e2683957 DDG	45	switch (priv->shr->state) {
	46	case VTPM_STATE_IDLE:
	47	return VTPM_STATUS_IDLE \| VTPM_STATUS_CANCELED;
	48	case VTPM_STATE_FINISH:
	49	return VTPM_STATUS_IDLE \| VTPM_STATUS_RESULT;
	50	case VTPM_STATE_SUBMIT:
	51	case VTPM_STATE_CANCEL: /* cancel requested, not yet canceled */
	52	return VTPM_STATUS_RUNNING;
	53	default:
	54	return 0;
	55	}
	56	}
	57
	58	static bool vtpm_req_canceled(struct tpm_chip *chip, u8 status)
	59	{
	60	return status & VTPM_STATUS_CANCELED;
	61	}
	62
	63	static void vtpm_cancel(struct tpm_chip *chip)
	64	{
9e0d39d8	65	struct tpm_private *priv = dev_get_drvdata(&chip->dev);
e2683957 DDG	66	priv->shr->state = VTPM_STATE_CANCEL;
	67	wmb();
	68	notify_remote_via_evtchn(priv->evtchn);
	69	}
	70
	71	static unsigned int shr_data_offset(struct vtpm_shared_page *shr)
	72	{
	73	return sizeof(shr) + sizeof(u32) shr->nr_extra_pages;
	74	}
	75
	76	static int vtpm_send(struct tpm_chip chip, u8 buf, size_t count)
	77	{
9e0d39d8	78	struct tpm_private *priv = dev_get_drvdata(&chip->dev);
e2683957 DDG	79	struct vtpm_shared_page *shr = priv->shr;
	80	unsigned int offset = shr_data_offset(shr);
	81
	82	u32 ordinal;
	83	unsigned long duration;
	84
	85	if (offset > PAGE_SIZE)
	86	return -EINVAL;
	87
	88	if (offset + count > PAGE_SIZE)
	89	return -EINVAL;
	90
	91	/* Wait for completion of any existing command or cancellation */
af782f33	92	if (wait_for_tpm_stat(chip, VTPM_STATUS_IDLE, chip->timeout_c,
6e599f6f	93	&priv->read_queue, true) < 0) {
e2683957 DDG	94	vtpm_cancel(chip);
	95	return -ETIME;
	96	}
	97
	98	memcpy(offset + (u8 *)shr, buf, count);
	99	shr->length = count;
	100	barrier();
	101	shr->state = VTPM_STATE_SUBMIT;
	102	wmb();
	103	notify_remote_via_evtchn(priv->evtchn);
	104
	105	ordinal = be32_to_cpu(((struct tpm_input_header*)buf)->ordinal);
	106	duration = tpm_calc_ordinal_duration(chip, ordinal);
	107
	108	if (wait_for_tpm_stat(chip, VTPM_STATUS_IDLE, duration,
6e599f6f	109	&priv->read_queue, true) < 0) {
e2683957 DDG	110	/* got a signal or timeout, try to cancel */
	111	vtpm_cancel(chip);
	112	return -ETIME;
	113	}
	114
9d6d12a9	115	return 0;
e2683957 DDG	116	}
	117
	118	static int vtpm_recv(struct tpm_chip chip, u8 buf, size_t count)
	119	{
9e0d39d8	120	struct tpm_private *priv = dev_get_drvdata(&chip->dev);
e2683957 DDG	121	struct vtpm_shared_page *shr = priv->shr;
	122	unsigned int offset = shr_data_offset(shr);
	123	size_t length = shr->length;
	124
	125	if (shr->state == VTPM_STATE_IDLE)
	126	return -ECANCELED;
	127
	128	/* In theory the wait at the end of _send makes this one unnecessary */
af782f33	129	if (wait_for_tpm_stat(chip, VTPM_STATUS_RESULT, chip->timeout_c,
6e599f6f	130	&priv->read_queue, true) < 0) {
e2683957 DDG	131	vtpm_cancel(chip);
	132	return -ETIME;
	133	}
	134
	135	if (offset > PAGE_SIZE)
	136	return -EIO;
	137
	138	if (offset + length > PAGE_SIZE)
	139	length = PAGE_SIZE - offset;
	140
	141	if (length > count)
	142	length = count;
	143
	144	memcpy(buf, offset + (u8 *)shr, length);
	145
	146	return length;
	147	}
	148
01ad1fa7	149	static const struct tpm_class_ops tpm_vtpm = {
e2683957 DDG	150	.status = vtpm_status,
	151	.recv = vtpm_recv,
	152	.send = vtpm_send,
	153	.cancel = vtpm_cancel,
	154	.req_complete_mask = VTPM_STATUS_IDLE \| VTPM_STATUS_RESULT,
	155	.req_complete_val = VTPM_STATUS_IDLE \| VTPM_STATUS_RESULT,
	156	.req_canceled = vtpm_req_canceled,
e2683957 DDG	157	};
	158
	159	static irqreturn_t tpmif_interrupt(int dummy, void *dev_id)
	160	{
	161	struct tpm_private *priv = dev_id;
	162
	163	switch (priv->shr->state) {
	164	case VTPM_STATE_IDLE:
	165	case VTPM_STATE_FINISH:
6e599f6f	166	wake_up_interruptible(&priv->read_queue);
e2683957 DDG	167	break;
	168	case VTPM_STATE_SUBMIT:
	169	case VTPM_STATE_CANCEL:
	170	default:
	171	break;
	172	}
	173	return IRQ_HANDLED;
	174	}
	175
	176	static int setup_chip(struct device dev, struct tpm_private priv)
	177	{
	178	struct tpm_chip *chip;
	179
afb5abc2 JS	180	chip = tpmm_chip_alloc(dev, &tpm_vtpm);
	181	if (IS_ERR(chip))
	182	return PTR_ERR(chip);
e2683957	183
6e599f6f	184	init_waitqueue_head(&priv->read_queue);
e2683957 DDG	185
e2683957 DDG	186	priv->chip = chip;
9e0d39d8	187	dev_set_drvdata(&chip->dev, priv);
e2683957 DDG	188
	189	return 0;
	190	}
	191
	192	/* caller must clean up in case of errors */
	193	static int setup_ring(struct xenbus_device dev, struct tpm_private priv)
	194	{
	195	struct xenbus_transaction xbt;
	196	const char *message = NULL;
	197	int rv;
ccc9d90a	198	grant_ref_t gref;
e2683957 DDG	199
	200	priv->shr = (void *)__get_free_page(GFP_KERNEL\|__GFP_ZERO);
	201	if (!priv->shr) {
	202	xenbus_dev_fatal(dev, -ENOMEM, "allocating shared ring");
	203	return -ENOMEM;
	204	}
	205
e9e61143	206	rv = xenbus_grant_ring(dev, priv->shr, 1, &gref);
e2683957 DDG	207	if (rv < 0)
	208	return rv;
	209
ccc9d90a	210	priv->ring_ref = gref;
e2683957 DDG	211
	212	rv = xenbus_alloc_evtchn(dev, &priv->evtchn);
	213	if (rv)
	214	return rv;
	215
	216	rv = bind_evtchn_to_irqhandler(priv->evtchn, tpmif_interrupt, 0,
	217	"tpmif", priv);
	218	if (rv <= 0) {
	219	xenbus_dev_fatal(dev, rv, "allocating TPM irq");
	220	return rv;
	221	}
570a3609	222	priv->irq = rv;
e2683957 DDG	223
	224	again:
	225	rv = xenbus_transaction_start(&xbt);
	226	if (rv) {
	227	xenbus_dev_fatal(dev, rv, "starting transaction");
	228	return rv;
	229	}
	230
	231	rv = xenbus_printf(xbt, dev->nodename,
	232	"ring-ref", "%u", priv->ring_ref);
	233	if (rv) {
	234	message = "writing ring-ref";
	235	goto abort_transaction;
	236	}
	237
	238	rv = xenbus_printf(xbt, dev->nodename, "event-channel", "%u",
	239	priv->evtchn);
	240	if (rv) {
	241	message = "writing event-channel";
	242	goto abort_transaction;
	243	}
	244
	245	rv = xenbus_printf(xbt, dev->nodename, "feature-protocol-v2", "1");
	246	if (rv) {
	247	message = "writing feature-protocol-v2";
	248	goto abort_transaction;
	249	}
	250
	251	rv = xenbus_transaction_end(xbt, 0);
	252	if (rv == -EAGAIN)
	253	goto again;
	254	if (rv) {
	255	xenbus_dev_fatal(dev, rv, "completing transaction");
	256	return rv;
	257	}
	258
	259	xenbus_switch_state(dev, XenbusStateInitialised);
	260
	261	return 0;
	262
	263	abort_transaction:
	264	xenbus_transaction_end(xbt, 1);
	265	if (message)
	266	xenbus_dev_error(dev, rv, "%s", message);
	267
	268	return rv;
	269	}
	270
	271	static void ring_free(struct tpm_private *priv)
	272	{
	273	if (!priv)
	274	return;
	275
	276	if (priv->ring_ref)
	277	gnttab_end_foreign_access(priv->ring_ref, 0,
	278	(unsigned long)priv->shr);
	279	else
	280	free_page((unsigned long)priv->shr);
	281
570a3609 CR	282	if (priv->irq)
570a3609 CR	283	unbind_from_irqhandler(priv->irq, priv);
e2683957 DDG	284
	285	kfree(priv);
	286	}
	287
	288	static int tpmfront_probe(struct xenbus_device *dev,
	289	const struct xenbus_device_id *id)
	290	{
	291	struct tpm_private *priv;
	292	int rv;
	293
	294	priv = kzalloc(sizeof(*priv), GFP_KERNEL);
	295	if (!priv) {
	296	xenbus_dev_fatal(dev, -ENOMEM, "allocating priv structure");
	297	return -ENOMEM;
	298	}
	299
	300	rv = setup_chip(&dev->dev, priv);
	301	if (rv) {
	302	kfree(priv);
	303	return rv;
	304	}
	305
	306	rv = setup_ring(dev, priv);
	307	if (rv) {
e2683957 DDG	308	ring_free(priv);
	309	return rv;
	310	}
	311
	312	tpm_get_timeouts(priv->chip);
	313
afb5abc2	314	return tpm_chip_register(priv->chip);
e2683957 DDG	315	}
	316
	317	static int tpmfront_remove(struct xenbus_device *dev)
	318	{
	319	struct tpm_chip *chip = dev_get_drvdata(&dev->dev);
9e0d39d8	320	struct tpm_private *priv = dev_get_drvdata(&chip->dev);
afb5abc2	321	tpm_chip_unregister(chip);
e2683957	322	ring_free(priv);
9e0d39d8	323	dev_set_drvdata(&chip->dev, NULL);
e2683957 DDG	324	return 0;
	325	}
	326
	327	static int tpmfront_resume(struct xenbus_device *dev)
	328	{
	329	/* A suspend/resume/migrate will interrupt a vTPM anyway */
	330	tpmfront_remove(dev);
	331	return tpmfront_probe(dev, NULL);
	332	}
	333
	334	static void backend_changed(struct xenbus_device *dev,
	335	enum xenbus_state backend_state)
	336	{
e2683957 DDG	337	switch (backend_state) {
	338	case XenbusStateInitialised:
	339	case XenbusStateConnected:
	340	if (dev->state == XenbusStateConnected)
	341	break;
	342
02409334 JG	343	if (!xenbus_read_unsigned(dev->otherend, "feature-protocol-v2",
02409334 JG	344	0)) {
e2683957 DDG	345	xenbus_dev_fatal(dev, -EINVAL,
	346	"vTPM protocol 2 required");
	347	return;
	348	}
	349	xenbus_switch_state(dev, XenbusStateConnected);
	350	break;
	351
	352	case XenbusStateClosing:
	353	case XenbusStateClosed:
	354	device_unregister(&dev->dev);
	355	xenbus_frontend_closed(dev);
	356	break;
	357	default:
	358	break;
	359	}
	360	}
	361
	362	static const struct xenbus_device_id tpmfront_ids[] = {
	363	{ "vtpm" },
	364	{ "" }
	365	};
	366	MODULE_ALIAS("xen:vtpm");
	367
95afae48 DV	368	static struct xenbus_driver tpmfront_driver = {
	369	.ids = tpmfront_ids,
	370	.probe = tpmfront_probe,
	371	.remove = tpmfront_remove,
	372	.resume = tpmfront_resume,
	373	.otherend_changed = backend_changed,
	374	};
e2683957 DDG	375
	376	static int __init xen_tpmfront_init(void)
	377	{
	378	if (!xen_domain())
	379	return -ENODEV;
	380
51c71a3b KRW	381	if (!xen_has_pv_devices())
	382	return -ENODEV;
	383
e2683957 DDG	384	return xenbus_register_frontend(&tpmfront_driver);
	385	}
	386	module_init(xen_tpmfront_init);
	387
	388	static void __exit xen_tpmfront_exit(void)
	389	{
	390	xenbus_unregister_driver(&tpmfront_driver);
	391	}
	392	module_exit(xen_tpmfront_exit);
	393
	394	MODULE_AUTHOR("Daniel De Graaf <dgdegra@tycho.nsa.gov>");
	395	MODULE_DESCRIPTION("Xen vTPM Driver");
	396	MODULE_LICENSE("GPL");