// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright 2021 Microsoft
 */

#include <linux/hyperv.h>

#include <drm/drm_print.h>
#include <drm/drm_simple_kms_helper.h>

#include "hyperv_drm.h"

#define VMBUS_RING_BUFSIZE (256 * 1024)
#define VMBUS_VSP_TIMEOUT (10 * HZ)

#define SYNTHVID_VERSION(major, minor) ((minor) << 16 | (major))
#define SYNTHVID_VER_GET_MAJOR(ver) (ver & 0x0000ffff)
#define SYNTHVID_VER_GET_MINOR(ver) ((ver & 0xffff0000) >> 16)

/* Support for VERSION_WIN7 is removed. #define is retained for reference. */
#define SYNTHVID_VERSION_WIN7 SYNTHVID_VERSION(3, 0)
#define SYNTHVID_VERSION_WIN8 SYNTHVID_VERSION(3, 2)
#define SYNTHVID_VERSION_WIN10 SYNTHVID_VERSION(3, 5)

#define SYNTHVID_DEPTH_WIN8 32
#define SYNTHVID_WIDTH_WIN8 1600
#define SYNTHVID_HEIGHT_WIN8 1200
#define SYNTHVID_FB_SIZE_WIN8 (8 * 1024 * 1024)

enum pipe_msg_type {
        PIPE_MSG_INVALID,
        PIPE_MSG_DATA,
        PIPE_MSG_MAX
};

enum synthvid_msg_type {
        SYNTHVID_ERROR                  = 0,
        SYNTHVID_VERSION_REQUEST        = 1,
        SYNTHVID_VERSION_RESPONSE       = 2,
        SYNTHVID_VRAM_LOCATION          = 3,
        SYNTHVID_VRAM_LOCATION_ACK      = 4,
        SYNTHVID_SITUATION_UPDATE       = 5,
        SYNTHVID_SITUATION_UPDATE_ACK   = 6,
        SYNTHVID_POINTER_POSITION       = 7,
        SYNTHVID_POINTER_SHAPE          = 8,
        SYNTHVID_FEATURE_CHANGE         = 9,
        SYNTHVID_DIRT                   = 10,
        SYNTHVID_RESOLUTION_REQUEST     = 13,
        SYNTHVID_RESOLUTION_RESPONSE    = 14,

        SYNTHVID_MAX                    = 15
};

struct pipe_msg_hdr {
        u32 type;
        u32 size; /* size of message after this field */
} __packed;

struct hvd_screen_info {
        u16 width;
        u16 height;
} __packed;

struct synthvid_msg_hdr {
        u32 type;
        u32 size;  /* size of this header + payload after this field */
} __packed;

struct synthvid_version_req {
        u32 version;
} __packed;

struct synthvid_version_resp {
        u32 version;
        u8 is_accepted;
        u8 max_video_outputs;
} __packed;

struct synthvid_vram_location {
        u64 user_ctx;
        u8 is_vram_gpa_specified;
        u64 vram_gpa;
} __packed;

struct synthvid_vram_location_ack {
        u64 user_ctx;
} __packed;

struct video_output_situation {
        u8 active;
        u32 vram_offset;
        u8 depth_bits;
        u32 width_pixels;
        u32 height_pixels;
        u32 pitch_bytes;
} __packed;

struct synthvid_situation_update {
        u64 user_ctx;
        u8 video_output_count;
        struct video_output_situation video_output[1];
} __packed;

struct synthvid_situation_update_ack {
        u64 user_ctx;
} __packed;

struct synthvid_pointer_position {
        u8 is_visible;
        u8 video_output;
        s32 image_x;
        s32 image_y;
} __packed;

#define SYNTHVID_CURSOR_MAX_X 96
#define SYNTHVID_CURSOR_MAX_Y 96
#define SYNTHVID_CURSOR_ARGB_PIXEL_SIZE 4
#define SYNTHVID_CURSOR_MAX_SIZE (SYNTHVID_CURSOR_MAX_X * \
        SYNTHVID_CURSOR_MAX_Y * SYNTHVID_CURSOR_ARGB_PIXEL_SIZE)
#define SYNTHVID_CURSOR_COMPLETE (-1)

struct synthvid_pointer_shape {
        u8 part_idx;
        u8 is_argb;
        u32 width; /* SYNTHVID_CURSOR_MAX_X at most */
        u32 height; /* SYNTHVID_CURSOR_MAX_Y at most */
        u32 hot_x; /* hotspot relative to upper-left of pointer image */
        u32 hot_y;
        u8 data[4];
} __packed;

struct synthvid_feature_change {
        u8 is_dirt_needed;
        u8 is_ptr_pos_needed;
        u8 is_ptr_shape_needed;
        u8 is_situ_needed;
} __packed;

struct rect {
        s32 x1, y1; /* top left corner */
        s32 x2, y2; /* bottom right corner, exclusive */
} __packed;

struct synthvid_dirt {
        u8 video_output;
        u8 dirt_count;
        struct rect rect[1];
} __packed;

#define SYNTHVID_EDID_BLOCK_SIZE        128
#define SYNTHVID_MAX_RESOLUTION_COUNT   64

struct synthvid_supported_resolution_req {
        u8 maximum_resolution_count;
} __packed;

struct synthvid_supported_resolution_resp {
        u8 edid_block[SYNTHVID_EDID_BLOCK_SIZE];
        u8 resolution_count;
        u8 default_resolution_index;
        u8 is_standard;
        struct hvd_screen_info supported_resolution[SYNTHVID_MAX_RESOLUTION_COUNT];
} __packed;

struct synthvid_msg {
        struct pipe_msg_hdr pipe_hdr;
        struct synthvid_msg_hdr vid_hdr;
        union {
                struct synthvid_version_req ver_req;
                struct synthvid_version_resp ver_resp;
                struct synthvid_vram_location vram;
                struct synthvid_vram_location_ack vram_ack;
                struct synthvid_situation_update situ;
                struct synthvid_situation_update_ack situ_ack;
                struct synthvid_pointer_position ptr_pos;
                struct synthvid_pointer_shape ptr_shape;
                struct synthvid_feature_change feature_chg;
                struct synthvid_dirt dirt;
                struct synthvid_supported_resolution_req resolution_req;
                struct synthvid_supported_resolution_resp resolution_resp;
        };
} __packed;

static inline bool hyperv_version_ge(u32 ver1, u32 ver2)
{
        if (SYNTHVID_VER_GET_MAJOR(ver1) > SYNTHVID_VER_GET_MAJOR(ver2) ||
            (SYNTHVID_VER_GET_MAJOR(ver1) == SYNTHVID_VER_GET_MAJOR(ver2) &&
             SYNTHVID_VER_GET_MINOR(ver1) >= SYNTHVID_VER_GET_MINOR(ver2)))
                return true;

        return false;
}

static inline int hyperv_sendpacket(struct hv_device *hdev, struct synthvid_msg *msg)
{
        static atomic64_t request_id = ATOMIC64_INIT(0);
        struct hyperv_drm_device *hv = hv_get_drvdata(hdev);
        int ret;

        msg->pipe_hdr.type = PIPE_MSG_DATA;
        msg->pipe_hdr.size = msg->vid_hdr.size;

        ret = vmbus_sendpacket(hdev->channel, msg,
                               msg->vid_hdr.size + sizeof(struct pipe_msg_hdr),
                               atomic64_inc_return(&request_id),
                               VM_PKT_DATA_INBAND, 0);

        if (ret)
                drm_err_ratelimited(&hv->dev, "Unable to send packet via vmbus; error %d\n", ret);

        return ret;
}

static int hyperv_negotiate_version(struct hv_device *hdev, u32 ver)
{
        struct hyperv_drm_device *hv = hv_get_drvdata(hdev);
        struct synthvid_msg *msg = (struct synthvid_msg *)hv->init_buf;
        struct drm_device *dev = &hv->dev;
        unsigned long t;

        memset(msg, 0, sizeof(struct synthvid_msg));
        msg->vid_hdr.type = SYNTHVID_VERSION_REQUEST;
        msg->vid_hdr.size = sizeof(struct synthvid_msg_hdr) +
                sizeof(struct synthvid_version_req);
        msg->ver_req.version = ver;
        hyperv_sendpacket(hdev, msg);

        t = wait_for_completion_timeout(&hv->wait, VMBUS_VSP_TIMEOUT);
        if (!t) {
                drm_err(dev, "Time out on waiting version response\n");
                return -ETIMEDOUT;
        }

        if (!msg->ver_resp.is_accepted) {
                drm_err(dev, "Version request not accepted\n");
                return -ENODEV;
        }

        hv->synthvid_version = ver;
        drm_info(dev, "Synthvid Version major %d, minor %d\n",
                 SYNTHVID_VER_GET_MAJOR(ver), SYNTHVID_VER_GET_MINOR(ver));

        return 0;
}

int hyperv_update_vram_location(struct hv_device *hdev, phys_addr_t vram_pp)
{
        struct hyperv_drm_device *hv = hv_get_drvdata(hdev);
        struct synthvid_msg *msg = (struct synthvid_msg *)hv->init_buf;
        struct drm_device *dev = &hv->dev;
        unsigned long t;

        memset(msg, 0, sizeof(struct synthvid_msg));
        msg->vid_hdr.type = SYNTHVID_VRAM_LOCATION;
        msg->vid_hdr.size = sizeof(struct synthvid_msg_hdr) +
                sizeof(struct synthvid_vram_location);
        msg->vram.user_ctx = vram_pp;
        msg->vram.vram_gpa = vram_pp;
        msg->vram.is_vram_gpa_specified = 1;
        hyperv_sendpacket(hdev, msg);

        t = wait_for_completion_timeout(&hv->wait, VMBUS_VSP_TIMEOUT);
        if (!t) {
                drm_err(dev, "Time out on waiting vram location ack\n");
                return -ETIMEDOUT;
        }
        if (msg->vram_ack.user_ctx != vram_pp) {
                drm_err(dev, "Unable to set VRAM location\n");
                return -ENODEV;
        }

        return 0;
}

int hyperv_update_situation(struct hv_device *hdev, u8 active, u32 bpp,
                            u32 w, u32 h, u32 pitch)
{
        struct synthvid_msg msg;

        memset(&msg, 0, sizeof(struct synthvid_msg));

        msg.vid_hdr.type = SYNTHVID_SITUATION_UPDATE;
        msg.vid_hdr.size = sizeof(struct synthvid_msg_hdr) +
                sizeof(struct synthvid_situation_update);
        msg.situ.user_ctx = 0;
        msg.situ.video_output_count = 1;
        msg.situ.video_output[0].active = active;
        /* vram_offset should always be 0 */
        msg.situ.video_output[0].vram_offset = 0;
        msg.situ.video_output[0].depth_bits = bpp;
        msg.situ.video_output[0].width_pixels = w;
        msg.situ.video_output[0].height_pixels = h;
        msg.situ.video_output[0].pitch_bytes = pitch;

        hyperv_sendpacket(hdev, &msg);

        return 0;
}

/*
 * Hyper-V supports a hardware cursor feature. It's not used by Linux VM,
 * but the Hyper-V host still draws a point as an extra mouse pointer,
 * which is unwanted, especially when Xorg is running.
 *
 * Hide the unwanted pointer, by setting msg.ptr_pos.is_visible = 1 and setting
 * the msg.ptr_shape.data. Note: setting msg.ptr_pos.is_visible to 0 doesn't
 * work in tests.
 *
 * The hyperv_hide_hw_ptr() is also called in the handler of the
 * SYNTHVID_FEATURE_CHANGE event, otherwise the host still draws an extra
 * unwanted mouse pointer after the VM Connection window is closed and reopened.
 */
int hyperv_hide_hw_ptr(struct hv_device *hdev)
{
        struct synthvid_msg msg;

        memset(&msg, 0, sizeof(struct synthvid_msg));
        msg.vid_hdr.type = SYNTHVID_POINTER_POSITION;
        msg.vid_hdr.size = sizeof(struct synthvid_msg_hdr) +
                sizeof(struct synthvid_pointer_position);
        msg.ptr_pos.is_visible = 1;
        msg.ptr_pos.video_output = 0;
        msg.ptr_pos.image_x = 0;
        msg.ptr_pos.image_y = 0;
        hyperv_sendpacket(hdev, &msg);

        memset(&msg, 0, sizeof(struct synthvid_msg));
        msg.vid_hdr.type = SYNTHVID_POINTER_SHAPE;
        msg.vid_hdr.size = sizeof(struct synthvid_msg_hdr) +
                sizeof(struct synthvid_pointer_shape);
        msg.ptr_shape.part_idx = SYNTHVID_CURSOR_COMPLETE;
        msg.ptr_shape.is_argb = 1;
        msg.ptr_shape.width = 1;
        msg.ptr_shape.height = 1;
        msg.ptr_shape.hot_x = 0;
        msg.ptr_shape.hot_y = 0;
        msg.ptr_shape.data[0] = 0;
        msg.ptr_shape.data[1] = 1;
        msg.ptr_shape.data[2] = 1;
        msg.ptr_shape.data[3] = 1;
        hyperv_sendpacket(hdev, &msg);

        return 0;
}

int hyperv_update_dirt(struct hv_device *hdev, struct drm_rect *rect)
{
        struct hyperv_drm_device *hv = hv_get_drvdata(hdev);
        struct synthvid_msg msg;

        if (!hv->dirt_needed)
                return 0;

        memset(&msg, 0, sizeof(struct synthvid_msg));

        msg.vid_hdr.type = SYNTHVID_DIRT;
        msg.vid_hdr.size = sizeof(struct synthvid_msg_hdr) +
                sizeof(struct synthvid_dirt);
        msg.dirt.video_output = 0;
        msg.dirt.dirt_count = 1;
        msg.dirt.rect[0].x1 = rect->x1;
        msg.dirt.rect[0].y1 = rect->y1;
        msg.dirt.rect[0].x2 = rect->x2;
        msg.dirt.rect[0].y2 = rect->y2;

        hyperv_sendpacket(hdev, &msg);

        return 0;
}

static int hyperv_get_supported_resolution(struct hv_device *hdev)
{
        struct hyperv_drm_device *hv = hv_get_drvdata(hdev);
        struct synthvid_msg *msg = (struct synthvid_msg *)hv->init_buf;
        struct drm_device *dev = &hv->dev;
        unsigned long t;
        u8 index;
        int i;

        memset(msg, 0, sizeof(struct synthvid_msg));
        msg->vid_hdr.type = SYNTHVID_RESOLUTION_REQUEST;
        msg->vid_hdr.size = sizeof(struct synthvid_msg_hdr) +
                sizeof(struct synthvid_supported_resolution_req);
        msg->resolution_req.maximum_resolution_count =
                SYNTHVID_MAX_RESOLUTION_COUNT;
        hyperv_sendpacket(hdev, msg);

        t = wait_for_completion_timeout(&hv->wait, VMBUS_VSP_TIMEOUT);
        if (!t) {
                drm_err(dev, "Time out on waiting resolution response\n");
                return -ETIMEDOUT;
        }

        if (msg->resolution_resp.resolution_count == 0) {
                drm_err(dev, "No supported resolutions\n");
                return -ENODEV;
        }

        index = msg->resolution_resp.default_resolution_index;
        if (index >= msg->resolution_resp.resolution_count) {
                drm_err(dev, "Invalid resolution index: %d\n", index);
                return -ENODEV;
        }

        for (i = 0; i < msg->resolution_resp.resolution_count; i++) {
                hv->screen_width_max = max_t(u32, hv->screen_width_max,
                        msg->resolution_resp.supported_resolution[i].width);
                hv->screen_height_max = max_t(u32, hv->screen_height_max,
                        msg->resolution_resp.supported_resolution[i].height);
        }

        hv->preferred_width =
                msg->resolution_resp.supported_resolution[index].width;
        hv->preferred_height =
                msg->resolution_resp.supported_resolution[index].height;

        return 0;
}

static void hyperv_receive_sub(struct hv_device *hdev)
{
        struct hyperv_drm_device *hv = hv_get_drvdata(hdev);
        struct synthvid_msg *msg;

        if (!hv)
                return;

        msg = (struct synthvid_msg *)hv->recv_buf;

        /* Complete the wait event */
        if (msg->vid_hdr.type == SYNTHVID_VERSION_RESPONSE ||
            msg->vid_hdr.type == SYNTHVID_RESOLUTION_RESPONSE ||
            msg->vid_hdr.type == SYNTHVID_VRAM_LOCATION_ACK) {
                memcpy(hv->init_buf, msg, VMBUS_MAX_PACKET_SIZE);
                complete(&hv->wait);
                return;
        }

        if (msg->vid_hdr.type == SYNTHVID_FEATURE_CHANGE) {
                hv->dirt_needed = msg->feature_chg.is_dirt_needed;
                if (hv->dirt_needed)
                        hyperv_hide_hw_ptr(hv->hdev);
        }
}

static void hyperv_receive(void *ctx)
{
        struct hv_device *hdev = ctx;
        struct hyperv_drm_device *hv = hv_get_drvdata(hdev);
        struct synthvid_msg *recv_buf;
        u32 bytes_recvd;
        u64 req_id;
        int ret;

        if (!hv)
                return;

        recv_buf = (struct synthvid_msg *)hv->recv_buf;

        do {
                ret = vmbus_recvpacket(hdev->channel, recv_buf,
                                       VMBUS_MAX_PACKET_SIZE,
                                       &bytes_recvd, &req_id);
                if (bytes_recvd > 0 &&
                    recv_buf->pipe_hdr.type == PIPE_MSG_DATA)
                        hyperv_receive_sub(hdev);
        } while (bytes_recvd > 0 && ret == 0);
}

int hyperv_connect_vsp(struct hv_device *hdev)
{
        struct hyperv_drm_device *hv = hv_get_drvdata(hdev);
        struct drm_device *dev = &hv->dev;
        int ret;

        ret = vmbus_open(hdev->channel, VMBUS_RING_BUFSIZE, VMBUS_RING_BUFSIZE,
                         NULL, 0, hyperv_receive, hdev);
        if (ret) {
                drm_err(dev, "Unable to open vmbus channel\n");
                return ret;
        }

        /* Negotiate the protocol version with host */
        switch (vmbus_proto_version) {
        case VERSION_WIN10:
        case VERSION_WIN10_V5:
                ret = hyperv_negotiate_version(hdev, SYNTHVID_VERSION_WIN10);
                if (!ret)
                        break;
                fallthrough;
        case VERSION_WIN8:
        case VERSION_WIN8_1:
                ret = hyperv_negotiate_version(hdev, SYNTHVID_VERSION_WIN8);
                break;
        default:
                ret = hyperv_negotiate_version(hdev, SYNTHVID_VERSION_WIN10);
                break;
        }

        if (ret) {
                drm_err(dev, "Synthetic video device version not accepted %d\n", ret);
                goto error;
        }

        hv->screen_depth = SYNTHVID_DEPTH_WIN8;

        if (hyperv_version_ge(hv->synthvid_version, SYNTHVID_VERSION_WIN10)) {
                ret = hyperv_get_supported_resolution(hdev);
                if (ret)
                        drm_err(dev, "Failed to get supported resolution from host, use default\n");
        } else {
                hv->screen_width_max = SYNTHVID_WIDTH_WIN8;
                hv->screen_height_max = SYNTHVID_HEIGHT_WIN8;
        }

        hv->mmio_megabytes = hdev->channel->offermsg.offer.mmio_megabytes;

        return 0;

error:
        vmbus_close(hdev->channel);
        return ret;
}