drivers/input/serio/hyperv-keyboard.c - hafnium/third_party/linux - Git at Google

 /*
  *  Copyright (c) 2013, Microsoft Corporation.
  *
  *  This program is free software; you can redistribute it and/or modify it
  *  under the terms and conditions of the GNU General Public License,
  *  version 2, as published by the Free Software Foundation.
  *
  *  This program is distributed in the hope 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.
  */

 #include <linux/init.h>
 #include <linux/module.h>
 #include <linux/device.h>
 #include <linux/completion.h>
 #include <linux/hyperv.h>
 #include <linux/serio.h>
 #include <linux/slab.h>

 /*
  * Current version 1.0
  *
  */
 #define SYNTH_KBD_VERSION_MAJOR 1
 #define SYNTH_KBD_VERSION_MINOR	0
 #define SYNTH_KBD_VERSION		(SYNTH_KBD_VERSION_MINOR | \
 					 (SYNTH_KBD_VERSION_MAJOR << 16))


 /*
  * Message types in the synthetic input protocol
  */
 enum synth_kbd_msg_type {
 	SYNTH_KBD_PROTOCOL_REQUEST = 1,
 	SYNTH_KBD_PROTOCOL_RESPONSE = 2,
 	SYNTH_KBD_EVENT = 3,
 	SYNTH_KBD_LED_INDICATORS = 4,
 };

 /*
  * Basic message structures.
  */
 struct synth_kbd_msg_hdr {
 	__le32 type;
 };

 struct synth_kbd_msg {
 	struct synth_kbd_msg_hdr header;
 	char data[]; /* Enclosed message */
 };

 union synth_kbd_version {
 	__le32 version;
 };

 /*
  * Protocol messages
  */
 struct synth_kbd_protocol_request {
 	struct synth_kbd_msg_hdr header;
 	union synth_kbd_version version_requested;
 };

 #define PROTOCOL_ACCEPTED	BIT(0)
 struct synth_kbd_protocol_response {
 	struct synth_kbd_msg_hdr header;
 	__le32 proto_status;
 };

 #define IS_UNICODE	BIT(0)
 #define IS_BREAK	BIT(1)
 #define IS_E0		BIT(2)
 #define IS_E1		BIT(3)
 struct synth_kbd_keystroke {
 	struct synth_kbd_msg_hdr header;
 	__le16 make_code;
 	__le16 reserved0;
 	__le32 info; /* Additional information */
 };


 #define HK_MAXIMUM_MESSAGE_SIZE 256

 #define KBD_VSC_SEND_RING_BUFFER_SIZE		(10 * PAGE_SIZE)
 #define KBD_VSC_RECV_RING_BUFFER_SIZE		(10 * PAGE_SIZE)

 #define XTKBD_EMUL0     0xe0
 #define XTKBD_EMUL1     0xe1
 #define XTKBD_RELEASE   0x80


 /*
  * Represents a keyboard device
  */
 struct hv_kbd_dev {
 	struct hv_device *hv_dev;
 	struct serio *hv_serio;
 	struct synth_kbd_protocol_request protocol_req;
 	struct synth_kbd_protocol_response protocol_resp;
 	/* Synchronize the request/response if needed */
 	struct completion wait_event;
 	spinlock_t lock; /* protects 'started' field */
 	bool started;
 };

 static void hv_kbd_on_receive(struct hv_device *hv_dev,
 			      struct synth_kbd_msg *msg, u32 msg_length)
 {
 	struct hv_kbd_dev *kbd_dev = hv_get_drvdata(hv_dev);
 	struct synth_kbd_keystroke *ks_msg;
 	unsigned long flags;
 	u32 msg_type = __le32_to_cpu(msg->header.type);
 	u32 info;
 	u16 scan_code;

 	switch (msg_type) {
 	case SYNTH_KBD_PROTOCOL_RESPONSE:
 		/*
 		 * Validate the information provided by the host.
 		 * If the host is giving us a bogus packet,
 		 * drop the packet (hoping the problem
 		 * goes away).
 		 */
 		if (msg_length < sizeof(struct synth_kbd_protocol_response)) {
 			dev_err(&hv_dev->device,
 				"Illegal protocol response packet (len: %d)\n",
 				msg_length);
 			break;
 		}

 		memcpy(&kbd_dev->protocol_resp, msg,
 			sizeof(struct synth_kbd_protocol_response));
 		complete(&kbd_dev->wait_event);
 		break;

 	case SYNTH_KBD_EVENT:
 		/*
 		 * Validate the information provided by the host.
 		 * If the host is giving us a bogus packet,
 		 * drop the packet (hoping the problem
 		 * goes away).
 		 */
 		if (msg_length < sizeof(struct  synth_kbd_keystroke)) {
 			dev_err(&hv_dev->device,
 				"Illegal keyboard event packet (len: %d)\n",
 				msg_length);
 			break;
 		}

 		ks_msg = (struct synth_kbd_keystroke *)msg;
 		info = __le32_to_cpu(ks_msg->info);

 		/*
 		 * Inject the information through the serio interrupt.
 		 */
 		spin_lock_irqsave(&kbd_dev->lock, flags);
 		if (kbd_dev->started) {
 			if (info & IS_E0)
 				serio_interrupt(kbd_dev->hv_serio,
 						XTKBD_EMUL0, 0);
 			if (info & IS_E1)
 				serio_interrupt(kbd_dev->hv_serio,
 						XTKBD_EMUL1, 0);
 			scan_code = __le16_to_cpu(ks_msg->make_code);
 			if (info & IS_BREAK)
 				scan_code |= XTKBD_RELEASE;

 			serio_interrupt(kbd_dev->hv_serio, scan_code, 0);
 		}
 		spin_unlock_irqrestore(&kbd_dev->lock, flags);

 		/*
 		 * Only trigger a wakeup on key down, otherwise
 		 * "echo freeze > /sys/power/state" can't really enter the
 		 * state because the Enter-UP can trigger a wakeup at once.
 		 */
 		if (!(info & IS_BREAK))
 			pm_wakeup_hard_event(&hv_dev->device);

 		break;

 	default:
 		dev_err(&hv_dev->device,
 			"unhandled message type %d\n", msg_type);
 	}
 }

 static void hv_kbd_handle_received_packet(struct hv_device *hv_dev,
 					  struct vmpacket_descriptor *desc,
 					  u32 bytes_recvd,
 					  u64 req_id)
 {
 	struct synth_kbd_msg *msg;
 	u32 msg_sz;

 	switch (desc->type) {
 	case VM_PKT_COMP:
 		break;

 	case VM_PKT_DATA_INBAND:
 		/*
 		 * We have a packet that has "inband" data. The API used
 		 * for retrieving the packet guarantees that the complete
 		 * packet is read. So, minimally, we should be able to
 		 * parse the payload header safely (assuming that the host
 		 * can be trusted.  Trusting the host seems to be a
 		 * reasonable assumption because in a virtualized
 		 * environment there is not whole lot you can do if you
 		 * don't trust the host.
 		 *
 		 * Nonetheless, let us validate if the host can be trusted
 		 * (in a trivial way).  The interesting aspect of this
 		 * validation is how do you recover if we discover that the
 		 * host is not to be trusted? Simply dropping the packet, I
 		 * don't think is an appropriate recovery.  In the interest
 		 * of failing fast, it may be better to crash the guest.
 		 * For now, I will just drop the packet!
 		 */

 		msg_sz = bytes_recvd - (desc->offset8 << 3);
 		if (msg_sz <= sizeof(struct synth_kbd_msg_hdr)) {
 			/*
 			 * Drop the packet and hope
 			 * the problem magically goes away.
 			 */
 			dev_err(&hv_dev->device,
 				"Illegal packet (type: %d, tid: %llx, size: %d)\n",
 				desc->type, req_id, msg_sz);
 			break;
 		}

 		msg = (void *)desc + (desc->offset8 << 3);
 		hv_kbd_on_receive(hv_dev, msg, msg_sz);
 		break;

 	default:
 		dev_err(&hv_dev->device,
 			"unhandled packet type %d, tid %llx len %d\n",
 			desc->type, req_id, bytes_recvd);
 		break;
 	}
 }

 static void hv_kbd_on_channel_callback(void *context)
 {
 	struct hv_device *hv_dev = context;
 	void *buffer;
 	int bufferlen = 0x100; /* Start with sensible size */
 	u32 bytes_recvd;
 	u64 req_id;
 	int error;

 	buffer = kmalloc(bufferlen, GFP_ATOMIC);
 	if (!buffer)
 		return;

 	while (1) {
 		error = vmbus_recvpacket_raw(hv_dev->channel, buffer, bufferlen,
 					     &bytes_recvd, &req_id);
 		switch (error) {
 		case 0:
 			if (bytes_recvd == 0) {
 				kfree(buffer);
 				return;
 			}

 			hv_kbd_handle_received_packet(hv_dev, buffer,
 						      bytes_recvd, req_id);
 			break;

 		case -ENOBUFS:
 			kfree(buffer);
 			/* Handle large packet */
 			bufferlen = bytes_recvd;
 			buffer = kmalloc(bytes_recvd, GFP_ATOMIC);
 			if (!buffer)
 				return;
 			break;
 		}
 	}
 }

 static int hv_kbd_connect_to_vsp(struct hv_device *hv_dev)
 {
 	struct hv_kbd_dev *kbd_dev = hv_get_drvdata(hv_dev);
 	struct synth_kbd_protocol_request *request;
 	struct synth_kbd_protocol_response *response;
 	u32 proto_status;
 	int error;

 	request = &kbd_dev->protocol_req;
 	memset(request, 0, sizeof(struct synth_kbd_protocol_request));
 	request->header.type = __cpu_to_le32(SYNTH_KBD_PROTOCOL_REQUEST);
 	request->version_requested.version = __cpu_to_le32(SYNTH_KBD_VERSION);

 	error = vmbus_sendpacket(hv_dev->channel, request,
 				 sizeof(struct synth_kbd_protocol_request),
 				 (unsigned long)request,
 				 VM_PKT_DATA_INBAND,
 				 VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
 	if (error)
 		return error;

 	if (!wait_for_completion_timeout(&kbd_dev->wait_event, 10 * HZ))
 		return -ETIMEDOUT;

 	response = &kbd_dev->protocol_resp;
 	proto_status = __le32_to_cpu(response->proto_status);
 	if (!(proto_status & PROTOCOL_ACCEPTED)) {
 		dev_err(&hv_dev->device,
 			"synth_kbd protocol request failed (version %d)\n",
 		        SYNTH_KBD_VERSION);
 		return -ENODEV;
 	}

 	return 0;
 }

 static int hv_kbd_start(struct serio *serio)
 {
 	struct hv_kbd_dev *kbd_dev = serio->port_data;
 	unsigned long flags;

 	spin_lock_irqsave(&kbd_dev->lock, flags);
 	kbd_dev->started = true;
 	spin_unlock_irqrestore(&kbd_dev->lock, flags);

 	return 0;
 }

 static void hv_kbd_stop(struct serio *serio)
 {
 	struct hv_kbd_dev *kbd_dev = serio->port_data;
 	unsigned long flags;

 	spin_lock_irqsave(&kbd_dev->lock, flags);
 	kbd_dev->started = false;
 	spin_unlock_irqrestore(&kbd_dev->lock, flags);
 }

 static int hv_kbd_probe(struct hv_device *hv_dev,
 			const struct hv_vmbus_device_id *dev_id)
 {
 	struct hv_kbd_dev *kbd_dev;
 	struct serio *hv_serio;
 	int error;

 	kbd_dev = kzalloc(sizeof(struct hv_kbd_dev), GFP_KERNEL);
 	hv_serio = kzalloc(sizeof(struct serio), GFP_KERNEL);
 	if (!kbd_dev || !hv_serio) {
 		error = -ENOMEM;
 		goto err_free_mem;
 	}

 	kbd_dev->hv_dev = hv_dev;
 	kbd_dev->hv_serio = hv_serio;
 	spin_lock_init(&kbd_dev->lock);
 	init_completion(&kbd_dev->wait_event);
 	hv_set_drvdata(hv_dev, kbd_dev);

 	hv_serio->dev.parent  = &hv_dev->device;
 	hv_serio->id.type = SERIO_8042_XL;
 	hv_serio->port_data = kbd_dev;
 	strlcpy(hv_serio->name, dev_name(&hv_dev->device),
 		sizeof(hv_serio->name));
 	strlcpy(hv_serio->phys, dev_name(&hv_dev->device),
 		sizeof(hv_serio->phys));

 	hv_serio->start = hv_kbd_start;
 	hv_serio->stop = hv_kbd_stop;

 	error = vmbus_open(hv_dev->channel,
 			   KBD_VSC_SEND_RING_BUFFER_SIZE,
 			   KBD_VSC_RECV_RING_BUFFER_SIZE,
 			   NULL, 0,
 			   hv_kbd_on_channel_callback,
 			   hv_dev);
 	if (error)
 		goto err_free_mem;

 	error = hv_kbd_connect_to_vsp(hv_dev);
 	if (error)
 		goto err_close_vmbus;

 	serio_register_port(kbd_dev->hv_serio);

 	device_init_wakeup(&hv_dev->device, true);

 	return 0;

 err_close_vmbus:
 	vmbus_close(hv_dev->channel);
 err_free_mem:
 	kfree(hv_serio);
 	kfree(kbd_dev);
 	return error;
 }

 static int hv_kbd_remove(struct hv_device *hv_dev)
 {
 	struct hv_kbd_dev *kbd_dev = hv_get_drvdata(hv_dev);

 	serio_unregister_port(kbd_dev->hv_serio);
 	vmbus_close(hv_dev->channel);
 	kfree(kbd_dev);

 	hv_set_drvdata(hv_dev, NULL);

 	return 0;
 }

 static const struct hv_vmbus_device_id id_table[] = {
 	/* Keyboard guid */
 	{ HV_KBD_GUID, },
 	{ },
 };

 MODULE_DEVICE_TABLE(vmbus, id_table);

 static struct  hv_driver hv_kbd_drv = {
 	.name = KBUILD_MODNAME,
 	.id_table = id_table,
 	.probe = hv_kbd_probe,
 	.remove = hv_kbd_remove,
 	.driver = {
 		.probe_type = PROBE_PREFER_ASYNCHRONOUS,
 	},
 };

 static int __init hv_kbd_init(void)
 {
 	return vmbus_driver_register(&hv_kbd_drv);
 }

 static void __exit hv_kbd_exit(void)
 {
 	vmbus_driver_unregister(&hv_kbd_drv);
 }

 MODULE_LICENSE("GPL");
 module_init(hv_kbd_init);
 module_exit(hv_kbd_exit);
	/*
	* Copyright (c) 2013, Microsoft Corporation.
	*
	* This program is free software; you can redistribute it and/or modify it
	* under the terms and conditions of the GNU General Public License,
	* version 2, as published by the Free Software Foundation.
	*
	* This program is distributed in the hope 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.
	*/

	#include <linux/init.h>
	#include <linux/module.h>
	#include <linux/device.h>
	#include <linux/completion.h>
	#include <linux/hyperv.h>
	#include <linux/serio.h>
	#include <linux/slab.h>

	/*
	* Current version 1.0
	*
	*/
	#define SYNTH_KBD_VERSION_MAJOR 1
	#define SYNTH_KBD_VERSION_MINOR 0
	#define SYNTH_KBD_VERSION (SYNTH_KBD_VERSION_MINOR \| \
	(SYNTH_KBD_VERSION_MAJOR << 16))


	/*
	* Message types in the synthetic input protocol
	*/
	enum synth_kbd_msg_type {
	SYNTH_KBD_PROTOCOL_REQUEST = 1,
	SYNTH_KBD_PROTOCOL_RESPONSE = 2,
	SYNTH_KBD_EVENT = 3,
	SYNTH_KBD_LED_INDICATORS = 4,
	};

	/*
	* Basic message structures.
	*/
	struct synth_kbd_msg_hdr {
	__le32 type;
	};

	struct synth_kbd_msg {
	struct synth_kbd_msg_hdr header;
	char data[]; /* Enclosed message */
	};

	union synth_kbd_version {
	__le32 version;
	};

	/*
	* Protocol messages
	*/
	struct synth_kbd_protocol_request {
	struct synth_kbd_msg_hdr header;
	union synth_kbd_version version_requested;
	};

	#define PROTOCOL_ACCEPTED BIT(0)
	struct synth_kbd_protocol_response {
	struct synth_kbd_msg_hdr header;
	__le32 proto_status;
	};

	#define IS_UNICODE BIT(0)
	#define IS_BREAK BIT(1)
	#define IS_E0 BIT(2)
	#define IS_E1 BIT(3)
	struct synth_kbd_keystroke {
	struct synth_kbd_msg_hdr header;
	__le16 make_code;
	__le16 reserved0;
	__le32 info; /* Additional information */
	};


	#define HK_MAXIMUM_MESSAGE_SIZE 256

	#define KBD_VSC_SEND_RING_BUFFER_SIZE (10 * PAGE_SIZE)
	#define KBD_VSC_RECV_RING_BUFFER_SIZE (10 * PAGE_SIZE)

	#define XTKBD_EMUL0 0xe0
	#define XTKBD_EMUL1 0xe1
	#define XTKBD_RELEASE 0x80


	/*
	* Represents a keyboard device
	*/
	struct hv_kbd_dev {
	struct hv_device *hv_dev;
	struct serio *hv_serio;
	struct synth_kbd_protocol_request protocol_req;
	struct synth_kbd_protocol_response protocol_resp;
	/* Synchronize the request/response if needed */
	struct completion wait_event;
	spinlock_t lock; /* protects 'started' field */
	bool started;
	};

	static void hv_kbd_on_receive(struct hv_device *hv_dev,
	struct synth_kbd_msg *msg, u32 msg_length)
	{
	struct hv_kbd_dev *kbd_dev = hv_get_drvdata(hv_dev);
	struct synth_kbd_keystroke *ks_msg;
	unsigned long flags;
	u32 msg_type = __le32_to_cpu(msg->header.type);
	u32 info;
	u16 scan_code;

	switch (msg_type) {
	case SYNTH_KBD_PROTOCOL_RESPONSE:
	/*
	* Validate the information provided by the host.
	* If the host is giving us a bogus packet,
	* drop the packet (hoping the problem
	* goes away).
	*/
	if (msg_length < sizeof(struct synth_kbd_protocol_response)) {
	dev_err(&hv_dev->device,
	"Illegal protocol response packet (len: %d)\n",
	msg_length);
	break;
	}

	memcpy(&kbd_dev->protocol_resp, msg,
	sizeof(struct synth_kbd_protocol_response));
	complete(&kbd_dev->wait_event);
	break;

	case SYNTH_KBD_EVENT:
	/*
	* Validate the information provided by the host.
	* If the host is giving us a bogus packet,
	* drop the packet (hoping the problem
	* goes away).
	*/
	if (msg_length < sizeof(struct synth_kbd_keystroke)) {
	dev_err(&hv_dev->device,
	"Illegal keyboard event packet (len: %d)\n",
	msg_length);
	break;
	}

	ks_msg = (struct synth_kbd_keystroke *)msg;
	info = __le32_to_cpu(ks_msg->info);

	/*
	* Inject the information through the serio interrupt.
	*/
	spin_lock_irqsave(&kbd_dev->lock, flags);
	if (kbd_dev->started) {
	if (info & IS_E0)
	serio_interrupt(kbd_dev->hv_serio,
	XTKBD_EMUL0, 0);
	if (info & IS_E1)
	serio_interrupt(kbd_dev->hv_serio,
	XTKBD_EMUL1, 0);
	scan_code = __le16_to_cpu(ks_msg->make_code);
	if (info & IS_BREAK)
	scan_code \|= XTKBD_RELEASE;

	serio_interrupt(kbd_dev->hv_serio, scan_code, 0);
	}
	spin_unlock_irqrestore(&kbd_dev->lock, flags);

	/*
	* Only trigger a wakeup on key down, otherwise
	* "echo freeze > /sys/power/state" can't really enter the
	* state because the Enter-UP can trigger a wakeup at once.
	*/
	if (!(info & IS_BREAK))
	pm_wakeup_hard_event(&hv_dev->device);

	break;

	default:
	dev_err(&hv_dev->device,
	"unhandled message type %d\n", msg_type);
	}
	}

	static void hv_kbd_handle_received_packet(struct hv_device *hv_dev,
	struct vmpacket_descriptor *desc,
	u32 bytes_recvd,
	u64 req_id)
	{
	struct synth_kbd_msg *msg;
	u32 msg_sz;

	switch (desc->type) {
	case VM_PKT_COMP:
	break;

	case VM_PKT_DATA_INBAND:
	/*
	* We have a packet that has "inband" data. The API used
	* for retrieving the packet guarantees that the complete
	* packet is read. So, minimally, we should be able to
	* parse the payload header safely (assuming that the host
	* can be trusted. Trusting the host seems to be a
	* reasonable assumption because in a virtualized
	* environment there is not whole lot you can do if you
	* don't trust the host.
	*
	* Nonetheless, let us validate if the host can be trusted
	* (in a trivial way). The interesting aspect of this
	* validation is how do you recover if we discover that the
	* host is not to be trusted? Simply dropping the packet, I
	* don't think is an appropriate recovery. In the interest
	* of failing fast, it may be better to crash the guest.
	* For now, I will just drop the packet!
	*/

	msg_sz = bytes_recvd - (desc->offset8 << 3);
	if (msg_sz <= sizeof(struct synth_kbd_msg_hdr)) {
	/*
	* Drop the packet and hope
	* the problem magically goes away.
	*/
	dev_err(&hv_dev->device,
	"Illegal packet (type: %d, tid: %llx, size: %d)\n",
	desc->type, req_id, msg_sz);
	break;
	}

	msg = (void *)desc + (desc->offset8 << 3);
	hv_kbd_on_receive(hv_dev, msg, msg_sz);
	break;

	default:
	dev_err(&hv_dev->device,
	"unhandled packet type %d, tid %llx len %d\n",
	desc->type, req_id, bytes_recvd);
	break;
	}
	}

	static void hv_kbd_on_channel_callback(void *context)
	{
	struct hv_device *hv_dev = context;
	void *buffer;
	int bufferlen = 0x100; /* Start with sensible size */
	u32 bytes_recvd;
	u64 req_id;
	int error;

	buffer = kmalloc(bufferlen, GFP_ATOMIC);
	if (!buffer)
	return;

	while (1) {
	error = vmbus_recvpacket_raw(hv_dev->channel, buffer, bufferlen,
	&bytes_recvd, &req_id);
	switch (error) {
	case 0:
	if (bytes_recvd == 0) {
	kfree(buffer);
	return;
	}

	hv_kbd_handle_received_packet(hv_dev, buffer,
	bytes_recvd, req_id);
	break;

	case -ENOBUFS:
	kfree(buffer);
	/* Handle large packet */
	bufferlen = bytes_recvd;
	buffer = kmalloc(bytes_recvd, GFP_ATOMIC);
	if (!buffer)
	return;
	break;
	}
	}
	}

	static int hv_kbd_connect_to_vsp(struct hv_device *hv_dev)
	{
	struct hv_kbd_dev *kbd_dev = hv_get_drvdata(hv_dev);
	struct synth_kbd_protocol_request *request;
	struct synth_kbd_protocol_response *response;
	u32 proto_status;
	int error;

	request = &kbd_dev->protocol_req;
	memset(request, 0, sizeof(struct synth_kbd_protocol_request));
	request->header.type = __cpu_to_le32(SYNTH_KBD_PROTOCOL_REQUEST);
	request->version_requested.version = __cpu_to_le32(SYNTH_KBD_VERSION);

	error = vmbus_sendpacket(hv_dev->channel, request,
	sizeof(struct synth_kbd_protocol_request),
	(unsigned long)request,
	VM_PKT_DATA_INBAND,
	VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
	if (error)
	return error;

	if (!wait_for_completion_timeout(&kbd_dev->wait_event, 10 * HZ))
	return -ETIMEDOUT;

	response = &kbd_dev->protocol_resp;
	proto_status = __le32_to_cpu(response->proto_status);
	if (!(proto_status & PROTOCOL_ACCEPTED)) {
	dev_err(&hv_dev->device,
	"synth_kbd protocol request failed (version %d)\n",
	SYNTH_KBD_VERSION);
	return -ENODEV;
	}

	return 0;
	}

	static int hv_kbd_start(struct serio *serio)
	{
	struct hv_kbd_dev *kbd_dev = serio->port_data;
	unsigned long flags;

	spin_lock_irqsave(&kbd_dev->lock, flags);
	kbd_dev->started = true;
	spin_unlock_irqrestore(&kbd_dev->lock, flags);

	return 0;
	}

	static void hv_kbd_stop(struct serio *serio)
	{
	struct hv_kbd_dev *kbd_dev = serio->port_data;
	unsigned long flags;

	spin_lock_irqsave(&kbd_dev->lock, flags);
	kbd_dev->started = false;
	spin_unlock_irqrestore(&kbd_dev->lock, flags);
	}

	static int hv_kbd_probe(struct hv_device *hv_dev,
	const struct hv_vmbus_device_id *dev_id)
	{
	struct hv_kbd_dev *kbd_dev;
	struct serio *hv_serio;
	int error;

	kbd_dev = kzalloc(sizeof(struct hv_kbd_dev), GFP_KERNEL);
	hv_serio = kzalloc(sizeof(struct serio), GFP_KERNEL);
	if (!kbd_dev \|\| !hv_serio) {
	error = -ENOMEM;
	goto err_free_mem;
	}

	kbd_dev->hv_dev = hv_dev;
	kbd_dev->hv_serio = hv_serio;
	spin_lock_init(&kbd_dev->lock);
	init_completion(&kbd_dev->wait_event);
	hv_set_drvdata(hv_dev, kbd_dev);

	hv_serio->dev.parent = &hv_dev->device;
	hv_serio->id.type = SERIO_8042_XL;
	hv_serio->port_data = kbd_dev;
	strlcpy(hv_serio->name, dev_name(&hv_dev->device),
	sizeof(hv_serio->name));
	strlcpy(hv_serio->phys, dev_name(&hv_dev->device),
	sizeof(hv_serio->phys));

	hv_serio->start = hv_kbd_start;
	hv_serio->stop = hv_kbd_stop;

	error = vmbus_open(hv_dev->channel,
	KBD_VSC_SEND_RING_BUFFER_SIZE,
	KBD_VSC_RECV_RING_BUFFER_SIZE,
	NULL, 0,
	hv_kbd_on_channel_callback,
	hv_dev);
	if (error)
	goto err_free_mem;

	error = hv_kbd_connect_to_vsp(hv_dev);
	if (error)
	goto err_close_vmbus;

	serio_register_port(kbd_dev->hv_serio);

	device_init_wakeup(&hv_dev->device, true);

	return 0;

	err_close_vmbus:
	vmbus_close(hv_dev->channel);
	err_free_mem:
	kfree(hv_serio);
	kfree(kbd_dev);
	return error;
	}

	static int hv_kbd_remove(struct hv_device *hv_dev)
	{
	struct hv_kbd_dev *kbd_dev = hv_get_drvdata(hv_dev);

	serio_unregister_port(kbd_dev->hv_serio);
	vmbus_close(hv_dev->channel);
	kfree(kbd_dev);

	hv_set_drvdata(hv_dev, NULL);

	return 0;
	}

	static const struct hv_vmbus_device_id id_table[] = {
	/* Keyboard guid */
	{ HV_KBD_GUID, },
	{ },
	};

	MODULE_DEVICE_TABLE(vmbus, id_table);

	static struct hv_driver hv_kbd_drv = {
	.name = KBUILD_MODNAME,
	.id_table = id_table,
	.probe = hv_kbd_probe,
	.remove = hv_kbd_remove,
	.driver = {
	.probe_type = PROBE_PREFER_ASYNCHRONOUS,
	},
	};

	static int __init hv_kbd_init(void)
	{
	return vmbus_driver_register(&hv_kbd_drv);
	}

	static void __exit hv_kbd_exit(void)
	{
	vmbus_driver_unregister(&hv_kbd_drv);
	}

	MODULE_LICENSE("GPL");
	module_init(hv_kbd_init);
	module_exit(hv_kbd_exit);