hid-hyperv.c

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/*
 *  Copyright (c) 2009, Citrix Systems, Inc.
 *  Copyright (c) 2010, Microsoft Corporation.
 *  Copyright (c) 2011, Novell Inc.
 *
 *  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/input.h>
#include <linux/hid.h>
#include <linux/hiddev.h>
#include <linux/hyperv.h>


struct hv_input_dev_info {
    unsigned int size;
    unsigned short vendor;
    unsigned short product;
    unsigned short version;
    unsigned short reserved[11];
};

/* The maximum size of a synthetic input message. */
#define SYNTHHID_MAX_INPUT_REPORT_SIZE 16

/*
 * Current version
 *
 * History:
 * Beta, RC < 2008/1/22        1,0
 * RC > 2008/1/22              2,0
 */
#define SYNTHHID_INPUT_VERSION_MAJOR    2
#define SYNTHHID_INPUT_VERSION_MINOR    0
#define SYNTHHID_INPUT_VERSION      (SYNTHHID_INPUT_VERSION_MINOR | \
                     (SYNTHHID_INPUT_VERSION_MAJOR << 16))


#pragma pack(push, 1)
/*
 * Message types in the synthetic input protocol
 */
enum synthhid_msg_type {
    SYNTH_HID_PROTOCOL_REQUEST,
    SYNTH_HID_PROTOCOL_RESPONSE,
    SYNTH_HID_INITIAL_DEVICE_INFO,
    SYNTH_HID_INITIAL_DEVICE_INFO_ACK,
    SYNTH_HID_INPUT_REPORT,
    SYNTH_HID_MAX
};

/*
 * Basic message structures.
 */
struct synthhid_msg_hdr {
    enum synthhid_msg_type type;
    u32 size;
};

struct synthhid_msg {
    struct synthhid_msg_hdr header;
    char data[1]; /* Enclosed message */
};

union synthhid_version {
    struct {
        u16 minor_version;
        u16 major_version;
    };
    u32 version;
};

/*
 * Protocol messages
 */
struct synthhid_protocol_request {
    struct synthhid_msg_hdr header;
    union synthhid_version version_requested;
};

struct synthhid_protocol_response {
    struct synthhid_msg_hdr header;
    union synthhid_version version_requested;
    unsigned char approved;
};

struct synthhid_device_info {
    struct synthhid_msg_hdr header;
    struct hv_input_dev_info hid_dev_info;
    struct hid_descriptor hid_descriptor;
};

struct synthhid_device_info_ack {
    struct synthhid_msg_hdr header;
    unsigned char reserved;
};

struct synthhid_input_report {
    struct synthhid_msg_hdr header;
    char buffer[1];
};

#pragma pack(pop)

#define INPUTVSC_SEND_RING_BUFFER_SIZE      (10*PAGE_SIZE)
#define INPUTVSC_RECV_RING_BUFFER_SIZE      (10*PAGE_SIZE)


enum pipe_prot_msg_type {
    PIPE_MESSAGE_INVALID,
    PIPE_MESSAGE_DATA,
    PIPE_MESSAGE_MAXIMUM
};


struct pipe_prt_msg {
    enum pipe_prot_msg_type type;
    u32 size;
    char data[1];
};

struct  mousevsc_prt_msg {
    enum pipe_prot_msg_type type;
    u32 size;
    union {
        struct synthhid_protocol_request request;
        struct synthhid_protocol_response response;
        struct synthhid_device_info_ack ack;
    };
};

/*
 * Represents an mousevsc device
 */
struct mousevsc_dev {
    struct hv_device    *device;
    bool            init_complete;
    bool            connected;
    struct mousevsc_prt_msg protocol_req;
    struct mousevsc_prt_msg protocol_resp;
    /* Synchronize the request/response if needed */
    struct completion   wait_event;
    int         dev_info_status;

    struct hid_descriptor   *hid_desc;
    unsigned char       *report_desc;
    u32         report_desc_size;
    struct hv_input_dev_info hid_dev_info;
    struct hid_device       *hid_device;
};


static struct mousevsc_dev *mousevsc_alloc_device(struct hv_device *device)
{
    struct mousevsc_dev *input_dev;

    input_dev = kzalloc(sizeof(struct mousevsc_dev), GFP_KERNEL);

    if (!input_dev)
        return NULL;

    input_dev->device = device;
    hv_set_drvdata(device, input_dev);
    init_completion(&input_dev->wait_event);
    input_dev->init_complete = false;

    return input_dev;
}

static void mousevsc_free_device(struct mousevsc_dev *device)
{
    kfree(device->hid_desc);
    kfree(device->report_desc);
    hv_set_drvdata(device->device, NULL);
    kfree(device);
}

static void mousevsc_on_receive_device_info(struct mousevsc_dev *input_device,
                struct synthhid_device_info *device_info)
{
    int ret = 0;
    struct hid_descriptor *desc;
    struct mousevsc_prt_msg ack;

    input_device->dev_info_status = -ENOMEM;

    input_device->hid_dev_info = device_info->hid_dev_info;
    desc = &device_info->hid_descriptor;
    if (desc->bLength == 0)
        goto cleanup;

    input_device->hid_desc = kzalloc(desc->bLength, GFP_ATOMIC);

    if (!input_device->hid_desc)
        goto cleanup;

    memcpy(input_device->hid_desc, desc, desc->bLength);

    input_device->report_desc_size = desc->desc[0].wDescriptorLength;
    if (input_device->report_desc_size == 0) {
        input_device->dev_info_status = -EINVAL;
        goto cleanup;
    }

    input_device->report_desc = kzalloc(input_device->report_desc_size,
                      GFP_ATOMIC);

    if (!input_device->report_desc) {
        input_device->dev_info_status = -ENOMEM;
        goto cleanup;
    }

    memcpy(input_device->report_desc,
           ((unsigned char *)desc) + desc->bLength,
           desc->desc[0].wDescriptorLength);

    /* Send the ack */
    memset(&ack, 0, sizeof(struct mousevsc_prt_msg));

    ack.type = PIPE_MESSAGE_DATA;
    ack.size = sizeof(struct synthhid_device_info_ack);

    ack.ack.header.type = SYNTH_HID_INITIAL_DEVICE_INFO_ACK;
    ack.ack.header.size = 1;
    ack.ack.reserved = 0;

    ret = vmbus_sendpacket(input_device->device->channel,
            &ack,
            sizeof(struct pipe_prt_msg) - sizeof(unsigned char) +
            sizeof(struct synthhid_device_info_ack),
            (unsigned long)&ack,
            VM_PKT_DATA_INBAND,
            VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);

    if (!ret)
        input_device->dev_info_status = 0;

cleanup:
    complete(&input_device->wait_event);

    return;
}

static void mousevsc_on_receive(struct hv_device *device,
                struct vmpacket_descriptor *packet)
{
    struct pipe_prt_msg *pipe_msg;
    struct synthhid_msg *hid_msg;
    struct mousevsc_dev *input_dev = hv_get_drvdata(device);
    struct synthhid_input_report *input_report;

    pipe_msg = (struct pipe_prt_msg *)((unsigned long)packet +
                        (packet->offset8 << 3));

    if (pipe_msg->type != PIPE_MESSAGE_DATA)
        return;

    hid_msg = (struct synthhid_msg *)pipe_msg->data;

    switch (hid_msg->header.type) {
    case SYNTH_HID_PROTOCOL_RESPONSE:
        /*
         * While it will be impossible for us to protect against
         * malicious/buggy hypervisor/host, add a check here to
         * ensure we don't corrupt memory.
         */
        if ((pipe_msg->size + sizeof(struct pipe_prt_msg)
            - sizeof(unsigned char))
            > sizeof(struct mousevsc_prt_msg)) {
            WARN_ON(1);
            break;
        }

        memcpy(&input_dev->protocol_resp, pipe_msg,
               pipe_msg->size + sizeof(struct pipe_prt_msg) -
               sizeof(unsigned char));
        complete(&input_dev->wait_event);
        break;

    case SYNTH_HID_INITIAL_DEVICE_INFO:
        WARN_ON(pipe_msg->size < sizeof(struct hv_input_dev_info));

        /*
         * Parse out the device info into device attr,
         * hid desc and report desc
         */
        mousevsc_on_receive_device_info(input_dev,
            (struct synthhid_device_info *)pipe_msg->data);
        break;
    case SYNTH_HID_INPUT_REPORT:
        input_report =
            (struct synthhid_input_report *)pipe_msg->data;
        if (!input_dev->init_complete)
            break;
        hid_input_report(input_dev->hid_device,
                HID_INPUT_REPORT, input_report->buffer,
                input_report->header.size, 1);
        break;
    default:
        pr_err("unsupported hid msg type - type %d len %d",
               hid_msg->header.type, hid_msg->header.size);
        break;
    }

}

static void mousevsc_on_channel_callback(void *context)
{
    const int packet_size = 0x100;
    int ret;
    struct hv_device *device = context;
    u32 bytes_recvd;
    u64 req_id;
    struct vmpacket_descriptor *desc;
    unsigned char   *buffer;
    int bufferlen = packet_size;

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

    do {
        ret = vmbus_recvpacket_raw(device->channel, buffer,
                    bufferlen, &bytes_recvd, &req_id);

        switch (ret) {
        case 0:
            if (bytes_recvd <= 0) {
                kfree(buffer);
                return;
            }
            desc = (struct vmpacket_descriptor *)buffer;

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

            case VM_PKT_DATA_INBAND:
                mousevsc_on_receive(device, desc);
                break;

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

            break;

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

            if (!buffer)
                return;

            break;
        }
    } while (1);

}

static int mousevsc_connect_to_vsp(struct hv_device *device)
{
    int ret = 0;
    int t;
    struct mousevsc_dev *input_dev = hv_get_drvdata(device);
    struct mousevsc_prt_msg *request;
    struct mousevsc_prt_msg *response;

    request = &input_dev->protocol_req;
    memset(request, 0, sizeof(struct mousevsc_prt_msg));

    request->type = PIPE_MESSAGE_DATA;
    request->size = sizeof(struct synthhid_protocol_request);
    request->request.header.type = SYNTH_HID_PROTOCOL_REQUEST;
    request->request.header.size = sizeof(unsigned int);
    request->request.version_requested.version = SYNTHHID_INPUT_VERSION;

    ret = vmbus_sendpacket(device->channel, request,
                sizeof(struct pipe_prt_msg) -
                sizeof(unsigned char) +
                sizeof(struct synthhid_protocol_request),
                (unsigned long)request,
                VM_PKT_DATA_INBAND,
                VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
    if (ret)
        goto cleanup;

    t = wait_for_completion_timeout(&input_dev->wait_event, 5*HZ);
    if (!t) {
        ret = -ETIMEDOUT;
        goto cleanup;
    }

    response = &input_dev->protocol_resp;

    if (!response->response.approved) {
        pr_err("synthhid protocol request failed (version %d)\n",
               SYNTHHID_INPUT_VERSION);
        ret = -ENODEV;
        goto cleanup;
    }

    t = wait_for_completion_timeout(&input_dev->wait_event, 5*HZ);
    if (!t) {
        ret = -ETIMEDOUT;
        goto cleanup;
    }

    /*
     * We should have gotten the device attr, hid desc and report
     * desc at this point
     */
    ret = input_dev->dev_info_status;

cleanup:
    return ret;
}

static int mousevsc_hid_parse(struct hid_device *hid)
{
    struct hv_device *dev = hid_get_drvdata(hid);
    struct mousevsc_dev *input_dev = hv_get_drvdata(dev);

    return hid_parse_report(hid, input_dev->report_desc,
                input_dev->report_desc_size);
}

static int mousevsc_hid_open(struct hid_device *hid)
{
    return 0;
}

static int mousevsc_hid_start(struct hid_device *hid)
{
    return 0;
}

static void mousevsc_hid_close(struct hid_device *hid)
{
}

static void mousevsc_hid_stop(struct hid_device *hid)
{
}

static struct hid_ll_driver mousevsc_ll_driver = {
    .parse = mousevsc_hid_parse,
    .open = mousevsc_hid_open,
    .close = mousevsc_hid_close,
    .start = mousevsc_hid_start,
    .stop = mousevsc_hid_stop,
};

static struct hid_driver mousevsc_hid_driver;

static int mousevsc_probe(struct hv_device *device,
            const struct hv_vmbus_device_id *dev_id)
{
    int ret;
    struct mousevsc_dev *input_dev;
    struct hid_device *hid_dev;

    input_dev = mousevsc_alloc_device(device);

    if (!input_dev)
        return -ENOMEM;

    ret = vmbus_open(device->channel,
        INPUTVSC_SEND_RING_BUFFER_SIZE,
        INPUTVSC_RECV_RING_BUFFER_SIZE,
        NULL,
        0,
        mousevsc_on_channel_callback,
        device
        );

    if (ret)
        goto probe_err0;

    ret = mousevsc_connect_to_vsp(device);

    if (ret)
        goto probe_err1;

    /* workaround SA-167 */
    if (input_dev->report_desc[14] == 0x25)
        input_dev->report_desc[14] = 0x29;

    hid_dev = hid_allocate_device();
    if (IS_ERR(hid_dev)) {
        ret = PTR_ERR(hid_dev);
        goto probe_err1;
    }

    hid_dev->ll_driver = &mousevsc_ll_driver;
    hid_dev->driver = &mousevsc_hid_driver;
    hid_dev->bus = BUS_VIRTUAL;
    hid_dev->vendor = input_dev->hid_dev_info.vendor;
    hid_dev->product = input_dev->hid_dev_info.product;
    hid_dev->version = input_dev->hid_dev_info.version;
    input_dev->hid_device = hid_dev;

    sprintf(hid_dev->name, "%s", "Microsoft Vmbus HID-compliant Mouse");

    hid_set_drvdata(hid_dev, device);

    ret = hid_add_device(hid_dev);
    if (ret)
        goto probe_err1;


    ret = hid_parse(hid_dev);
    if (ret) {
        hid_err(hid_dev, "parse failed\n");
        goto probe_err2;
    }

    ret = hid_hw_start(hid_dev, HID_CONNECT_HIDINPUT | HID_CONNECT_HIDDEV);

    if (ret) {
        hid_err(hid_dev, "hw start failed\n");
        goto probe_err2;
    }

    input_dev->connected = true;
    input_dev->init_complete = true;

    return ret;

probe_err2:
    hid_destroy_device(hid_dev);

probe_err1:
    vmbus_close(device->channel);

probe_err0:
    mousevsc_free_device(input_dev);

    return ret;
}


static int mousevsc_remove(struct hv_device *dev)
{
    struct mousevsc_dev *input_dev = hv_get_drvdata(dev);

    vmbus_close(dev->channel);
    hid_hw_stop(input_dev->hid_device);
    hid_destroy_device(input_dev->hid_device);
    mousevsc_free_device(input_dev);

    return 0;
}

static const struct hv_vmbus_device_id id_table[] = {
    /* Mouse guid */
    { VMBUS_DEVICE(0x9E, 0xB6, 0xA8, 0xCF, 0x4A, 0x5B, 0xc0, 0x4c,
               0xB9, 0x8B, 0x8B, 0xA1, 0xA1, 0xF3, 0xF9, 0x5A) },
    { },
};

MODULE_DEVICE_TABLE(vmbus, id_table);

static struct  hv_driver mousevsc_drv = {
    .name = KBUILD_MODNAME,
    .id_table = id_table,
    .probe = mousevsc_probe,
    .remove = mousevsc_remove,
};

static int __init mousevsc_init(void)
{
    return vmbus_driver_register(&mousevsc_drv);
}

static void __exit mousevsc_exit(void)
{
    vmbus_driver_unregister(&mousevsc_drv);
}

MODULE_LICENSE("GPL");
MODULE_VERSION(HV_DRV_VERSION);
module_init(mousevsc_init);
module_exit(mousevsc_exit);