/*
 * Copyright 2017 Intel Corporation. All rights reserved.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice (including the next
 * paragraph) shall be included in all copies or substantial portions of the
 * Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
 * DEALINGS IN THE SOFTWARE.
 *
 * Authors:
 *    Zhiyuan Lv <zhiyuan.lv@intel.com>
 *
 * Contributors:
 *    Xiaoguang Chen
 *    Tina Zhang <tina.zhang@intel.com>
 */

#include <linux/dma-buf.h>
#include <linux/vfio.h>

#include "i915_drv.h"
#include "gvt.h"

#define GEN8_DECODE_PTE(pte) (pte & GENMASK_ULL(63, 12))

static int vgpu_pin_dma_address(struct intel_vgpu *vgpu,
                                unsigned long size,
                                dma_addr_t dma_addr)
{
        int ret = 0;

        if (intel_gvt_hypervisor_dma_pin_guest_page(vgpu, dma_addr))
                ret = -EINVAL;

        return ret;
}

static void vgpu_unpin_dma_address(struct intel_vgpu *vgpu,
                                   dma_addr_t dma_addr)
{
        intel_gvt_hypervisor_dma_unmap_guest_page(vgpu, dma_addr);
}

static int vgpu_gem_get_pages(
                struct drm_i915_gem_object *obj)
{
        struct drm_i915_private *dev_priv = to_i915(obj->base.dev);
        struct intel_vgpu *vgpu;
        struct sg_table *st;
        struct scatterlist *sg;
        int i, j, ret;
        gen8_pte_t __iomem *gtt_entries;
        struct intel_vgpu_fb_info *fb_info;
        u32 page_num;

        fb_info = (struct intel_vgpu_fb_info *)obj->gvt_info;
        if (drm_WARN_ON(&dev_priv->drm, !fb_info))
                return -ENODEV;

        vgpu = fb_info->obj->vgpu;
        if (drm_WARN_ON(&dev_priv->drm, !vgpu))
                return -ENODEV;

        st = kmalloc(sizeof(*st), GFP_KERNEL);
        if (unlikely(!st))
                return -ENOMEM;

        page_num = obj->base.size >> PAGE_SHIFT;
        ret = sg_alloc_table(st, page_num, GFP_KERNEL);
        if (ret) {
                kfree(st);
                return ret;
        }
        gtt_entries = (gen8_pte_t __iomem *)dev_priv->ggtt.gsm +
                (fb_info->start >> PAGE_SHIFT);
        for_each_sg(st->sgl, sg, page_num, i) {
                dma_addr_t dma_addr =
                        GEN8_DECODE_PTE(readq(&gtt_entries[i]));
                if (vgpu_pin_dma_address(vgpu, PAGE_SIZE, dma_addr)) {
                        ret = -EINVAL;
                        goto out;
                }

                sg->offset = 0;
                sg->length = PAGE_SIZE;
                sg_dma_len(sg) = PAGE_SIZE;
                sg_dma_address(sg) = dma_addr;
        }

        __i915_gem_object_set_pages(obj, st, PAGE_SIZE);
out:
        if (ret) {
                dma_addr_t dma_addr;

                for_each_sg(st->sgl, sg, i, j) {
                        dma_addr = sg_dma_address(sg);
                        if (dma_addr)
                                vgpu_unpin_dma_address(vgpu, dma_addr);
                }
                sg_free_table(st);
                kfree(st);
        }

        return ret;

}

static void vgpu_gem_put_pages(struct drm_i915_gem_object *obj,
                struct sg_table *pages)
{
        struct scatterlist *sg;

        if (obj->base.dma_buf) {
                struct intel_vgpu_fb_info *fb_info = obj->gvt_info;
                struct intel_vgpu_dmabuf_obj *obj = fb_info->obj;
                struct intel_vgpu *vgpu = obj->vgpu;
                int i;

                for_each_sg(pages->sgl, sg, fb_info->size, i)
                        vgpu_unpin_dma_address(vgpu,
                                               sg_dma_address(sg));
        }

        sg_free_table(pages);
        kfree(pages);
}

static void dmabuf_gem_object_free(struct kref *kref)
{
        struct intel_vgpu_dmabuf_obj *obj =
                container_of(kref, struct intel_vgpu_dmabuf_obj, kref);
        struct intel_vgpu *vgpu = obj->vgpu;
        struct list_head *pos;
        struct intel_vgpu_dmabuf_obj *dmabuf_obj;

        if (vgpu && vgpu->active && !list_empty(&vgpu->dmabuf_obj_list_head)) {
                list_for_each(pos, &vgpu->dmabuf_obj_list_head) {
                        dmabuf_obj = container_of(pos,
                                        struct intel_vgpu_dmabuf_obj, list);
                        if (dmabuf_obj == obj) {
                                list_del(pos);
                                intel_gvt_hypervisor_put_vfio_device(vgpu);
                                idr_remove(&vgpu->object_idr,
                                           dmabuf_obj->dmabuf_id);
                                kfree(dmabuf_obj->info);
                                kfree(dmabuf_obj);
                                break;
                        }
                }
        } else {
                /* Free the orphan dmabuf_objs here */
                kfree(obj->info);
                kfree(obj);
        }
}


static inline void dmabuf_obj_get(struct intel_vgpu_dmabuf_obj *obj)
{
        kref_get(&obj->kref);
}

static inline void dmabuf_obj_put(struct intel_vgpu_dmabuf_obj *obj)
{
        kref_put(&obj->kref, dmabuf_gem_object_free);
}

static void vgpu_gem_release(struct drm_i915_gem_object *gem_obj)
{

        struct intel_vgpu_fb_info *fb_info = gem_obj->gvt_info;
        struct intel_vgpu_dmabuf_obj *obj = fb_info->obj;
        struct intel_vgpu *vgpu = obj->vgpu;

        if (vgpu) {
                mutex_lock(&vgpu->dmabuf_lock);
                gem_obj->base.dma_buf = NULL;
                dmabuf_obj_put(obj);
                mutex_unlock(&vgpu->dmabuf_lock);
        } else {
                /* vgpu is NULL, as it has been removed already */
                gem_obj->base.dma_buf = NULL;
                dmabuf_obj_put(obj);
        }
}

static const struct drm_i915_gem_object_ops intel_vgpu_gem_ops = {
        .name = "i915_gem_object_vgpu",
        .flags = I915_GEM_OBJECT_IS_PROXY,
        .get_pages = vgpu_gem_get_pages,
        .put_pages = vgpu_gem_put_pages,
        .release = vgpu_gem_release,
};

static struct drm_i915_gem_object *vgpu_create_gem(struct drm_device *dev,
                struct intel_vgpu_fb_info *info)
{
        static struct lock_class_key lock_class;
        struct drm_i915_private *dev_priv = to_i915(dev);
        struct drm_i915_gem_object *obj;

        obj = i915_gem_object_alloc();
        if (obj == NULL)
                return NULL;

        drm_gem_private_object_init(dev, &obj->base,
                roundup(info->size, PAGE_SIZE));
        i915_gem_object_init(obj, &intel_vgpu_gem_ops, &lock_class);
        i915_gem_object_set_readonly(obj);

        obj->read_domains = I915_GEM_DOMAIN_GTT;
        obj->write_domain = 0;
        if (INTEL_GEN(dev_priv) >= 9) {
                unsigned int tiling_mode = 0;
                unsigned int stride = 0;

                switch (info->drm_format_mod) {
                case DRM_FORMAT_MOD_LINEAR:
                        tiling_mode = I915_TILING_NONE;
                        break;
                case I915_FORMAT_MOD_X_TILED:
                        tiling_mode = I915_TILING_X;
                        stride = info->stride;
                        break;
                case I915_FORMAT_MOD_Y_TILED:
                case I915_FORMAT_MOD_Yf_TILED:
                        tiling_mode = I915_TILING_Y;
                        stride = info->stride;
                        break;
                default:
                        gvt_dbg_core("invalid drm_format_mod %llx for tiling\n",
                                     info->drm_format_mod);
                }
                obj->tiling_and_stride = tiling_mode | stride;
        } else {
                obj->tiling_and_stride = info->drm_format_mod ?
                                        I915_TILING_X : 0;
        }

        return obj;
}

static bool validate_hotspot(struct intel_vgpu_cursor_plane_format *c)
{
        if (c && c->x_hot <= c->width && c->y_hot <= c->height)
                return true;
        else
                return false;
}

static int vgpu_get_plane_info(struct drm_device *dev,
                struct intel_vgpu *vgpu,
                struct intel_vgpu_fb_info *info,
                int plane_id)
{
        struct intel_vgpu_primary_plane_format p;
        struct intel_vgpu_cursor_plane_format c;
        int ret, tile_height = 1;

        memset(info, 0, sizeof(*info));

        if (plane_id == DRM_PLANE_TYPE_PRIMARY) {
                ret = intel_vgpu_decode_primary_plane(vgpu, &p);
                if (ret)
                        return ret;
                info->start = p.base;
                info->start_gpa = p.base_gpa;
                info->width = p.width;
                info->height = p.height;
                info->stride = p.stride;
                info->drm_format = p.drm_format;

                switch (p.tiled) {
                case PLANE_CTL_TILED_LINEAR:
                        info->drm_format_mod = DRM_FORMAT_MOD_LINEAR;
                        break;
                case PLANE_CTL_TILED_X:
                        info->drm_format_mod = I915_FORMAT_MOD_X_TILED;
                        tile_height = 8;
                        break;
                case PLANE_CTL_TILED_Y:
                        info->drm_format_mod = I915_FORMAT_MOD_Y_TILED;
                        tile_height = 32;
                        break;
                case PLANE_CTL_TILED_YF:
                        info->drm_format_mod = I915_FORMAT_MOD_Yf_TILED;
                        tile_height = 32;
                        break;
                default:
                        gvt_vgpu_err("invalid tiling mode: %x\n", p.tiled);
                }
        } else if (plane_id == DRM_PLANE_TYPE_CURSOR) {
                ret = intel_vgpu_decode_cursor_plane(vgpu, &c);
                if (ret)
                        return ret;
                info->start = c.base;
                info->start_gpa = c.base_gpa;
                info->width = c.width;
                info->height = c.height;
                info->stride = c.width * (c.bpp / 8);
                info->drm_format = c.drm_format;
                info->drm_format_mod = 0;
                info->x_pos = c.x_pos;
                info->y_pos = c.y_pos;

                if (validate_hotspot(&c)) {
                        info->x_hot = c.x_hot;
                        info->y_hot = c.y_hot;
                } else {
                        info->x_hot = UINT_MAX;
                        info->y_hot = UINT_MAX;
                }
        } else {
                gvt_vgpu_err("invalid plane id:%d\n", plane_id);
                return -EINVAL;
        }

        info->size = info->stride * roundup(info->height, tile_height);
        if (info->size == 0) {
                gvt_vgpu_err("fb size is zero\n");
                return -EINVAL;
        }

        if (info->start & (PAGE_SIZE - 1)) {
                gvt_vgpu_err("Not aligned fb address:0x%llx\n", info->start);
                return -EFAULT;
        }

        if (!intel_gvt_ggtt_validate_range(vgpu, info->start, info->size)) {
                gvt_vgpu_err("invalid gma addr\n");
                return -EFAULT;
        }

        return 0;
}

static struct intel_vgpu_dmabuf_obj *
pick_dmabuf_by_info(struct intel_vgpu *vgpu,
                    struct intel_vgpu_fb_info *latest_info)
{
        struct list_head *pos;
        struct intel_vgpu_fb_info *fb_info;
        struct intel_vgpu_dmabuf_obj *dmabuf_obj = NULL;
        struct intel_vgpu_dmabuf_obj *ret = NULL;

        list_for_each(pos, &vgpu->dmabuf_obj_list_head) {
                dmabuf_obj = container_of(pos, struct intel_vgpu_dmabuf_obj,
                                                list);
                if ((dmabuf_obj == NULL) ||
                    (dmabuf_obj->info == NULL))
                        continue;

                fb_info = (struct intel_vgpu_fb_info *)dmabuf_obj->info;
                if ((fb_info->start == latest_info->start) &&
                    (fb_info->start_gpa == latest_info->start_gpa) &&
                    (fb_info->size == latest_info->size) &&
                    (fb_info->drm_format_mod == latest_info->drm_format_mod) &&
                    (fb_info->drm_format == latest_info->drm_format) &&
                    (fb_info->width == latest_info->width) &&
                    (fb_info->height == latest_info->height)) {
                        ret = dmabuf_obj;
                        break;
                }
        }

        return ret;
}

static struct intel_vgpu_dmabuf_obj *
pick_dmabuf_by_num(struct intel_vgpu *vgpu, u32 id)
{
        struct list_head *pos;
        struct intel_vgpu_dmabuf_obj *dmabuf_obj = NULL;
        struct intel_vgpu_dmabuf_obj *ret = NULL;

        list_for_each(pos, &vgpu->dmabuf_obj_list_head) {
                dmabuf_obj = container_of(pos, struct intel_vgpu_dmabuf_obj,
                                                list);
                if (!dmabuf_obj)
                        continue;

                if (dmabuf_obj->dmabuf_id == id) {
                        ret = dmabuf_obj;
                        break;
                }
        }

        return ret;
}

static void update_fb_info(struct vfio_device_gfx_plane_info *gvt_dmabuf,
                      struct intel_vgpu_fb_info *fb_info)
{
        gvt_dmabuf->drm_format = fb_info->drm_format;
        gvt_dmabuf->drm_format_mod = fb_info->drm_format_mod;
        gvt_dmabuf->width = fb_info->width;
        gvt_dmabuf->height = fb_info->height;
        gvt_dmabuf->stride = fb_info->stride;
        gvt_dmabuf->size = fb_info->size;
        gvt_dmabuf->x_pos = fb_info->x_pos;
        gvt_dmabuf->y_pos = fb_info->y_pos;
        gvt_dmabuf->x_hot = fb_info->x_hot;
        gvt_dmabuf->y_hot = fb_info->y_hot;
}

int intel_vgpu_query_plane(struct intel_vgpu *vgpu, void *args)
{
        struct drm_device *dev = &vgpu->gvt->gt->i915->drm;
        struct vfio_device_gfx_plane_info *gfx_plane_info = args;
        struct intel_vgpu_dmabuf_obj *dmabuf_obj;
        struct intel_vgpu_fb_info fb_info;
        int ret = 0;

        if (gfx_plane_info->flags == (VFIO_GFX_PLANE_TYPE_DMABUF |
                                       VFIO_GFX_PLANE_TYPE_PROBE))
                return ret;
        else if ((gfx_plane_info->flags & ~VFIO_GFX_PLANE_TYPE_DMABUF) ||
                        (!gfx_plane_info->flags))
                return -EINVAL;

        ret = vgpu_get_plane_info(dev, vgpu, &fb_info,
                                        gfx_plane_info->drm_plane_type);
        if (ret != 0)
                goto out;

        mutex_lock(&vgpu->dmabuf_lock);
        /* If exists, pick up the exposed dmabuf_obj */
        dmabuf_obj = pick_dmabuf_by_info(vgpu, &fb_info);
        if (dmabuf_obj) {
                update_fb_info(gfx_plane_info, &fb_info);
                gfx_plane_info->dmabuf_id = dmabuf_obj->dmabuf_id;

                /* This buffer may be released between query_plane ioctl and
                 * get_dmabuf ioctl. Add the refcount to make sure it won't
                 * be released between the two ioctls.
                 */
                if (!dmabuf_obj->initref) {
                        dmabuf_obj->initref = true;
                        dmabuf_obj_get(dmabuf_obj);
                }
                ret = 0;
                gvt_dbg_dpy("vgpu%d: re-use dmabuf_obj ref %d, id %d\n",
                            vgpu->id, kref_read(&dmabuf_obj->kref),
                            gfx_plane_info->dmabuf_id);
                mutex_unlock(&vgpu->dmabuf_lock);
                goto out;
        }

        mutex_unlock(&vgpu->dmabuf_lock);

        /* Need to allocate a new one*/
        dmabuf_obj = kmalloc(sizeof(struct intel_vgpu_dmabuf_obj), GFP_KERNEL);
        if (unlikely(!dmabuf_obj)) {
                gvt_vgpu_err("alloc dmabuf_obj failed\n");
                ret = -ENOMEM;
                goto out;
        }

        dmabuf_obj->info = kmalloc(sizeof(struct intel_vgpu_fb_info),
                                   GFP_KERNEL);
        if (unlikely(!dmabuf_obj->info)) {
                gvt_vgpu_err("allocate intel vgpu fb info failed\n");
                ret = -ENOMEM;
                goto out_free_dmabuf;
        }
        memcpy(dmabuf_obj->info, &fb_info, sizeof(struct intel_vgpu_fb_info));

        ((struct intel_vgpu_fb_info *)dmabuf_obj->info)->obj = dmabuf_obj;

        dmabuf_obj->vgpu = vgpu;

        ret = idr_alloc(&vgpu->object_idr, dmabuf_obj, 1, 0, GFP_NOWAIT);
        if (ret < 0)
                goto out_free_info;
        gfx_plane_info->dmabuf_id = ret;
        dmabuf_obj->dmabuf_id = ret;

        dmabuf_obj->initref = true;

        kref_init(&dmabuf_obj->kref);

        mutex_lock(&vgpu->dmabuf_lock);
        if (intel_gvt_hypervisor_get_vfio_device(vgpu)) {
                gvt_vgpu_err("get vfio device failed\n");
                mutex_unlock(&vgpu->dmabuf_lock);
                goto out_free_info;
        }
        mutex_unlock(&vgpu->dmabuf_lock);

        update_fb_info(gfx_plane_info, &fb_info);

        INIT_LIST_HEAD(&dmabuf_obj->list);
        mutex_lock(&vgpu->dmabuf_lock);
        list_add_tail(&dmabuf_obj->list, &vgpu->dmabuf_obj_list_head);
        mutex_unlock(&vgpu->dmabuf_lock);

        gvt_dbg_dpy("vgpu%d: %s new dmabuf_obj ref %d, id %d\n", vgpu->id,
                    __func__, kref_read(&dmabuf_obj->kref), ret);

        return 0;

out_free_info:
        kfree(dmabuf_obj->info);
out_free_dmabuf:
        kfree(dmabuf_obj);
out:
        /* ENODEV means plane isn't ready, which might be a normal case. */
        return (ret == -ENODEV) ? 0 : ret;
}

/* To associate an exposed dmabuf with the dmabuf_obj */
int intel_vgpu_get_dmabuf(struct intel_vgpu *vgpu, unsigned int dmabuf_id)
{
        struct drm_device *dev = &vgpu->gvt->gt->i915->drm;
        struct intel_vgpu_dmabuf_obj *dmabuf_obj;
        struct drm_i915_gem_object *obj;
        struct dma_buf *dmabuf;
        int dmabuf_fd;
        int ret = 0;

        mutex_lock(&vgpu->dmabuf_lock);

        dmabuf_obj = pick_dmabuf_by_num(vgpu, dmabuf_id);
        if (dmabuf_obj == NULL) {
                gvt_vgpu_err("invalid dmabuf id:%d\n", dmabuf_id);
                ret = -EINVAL;
                goto out;
        }

        obj = vgpu_create_gem(dev, dmabuf_obj->info);
        if (obj == NULL) {
                gvt_vgpu_err("create gvt gem obj failed\n");
                ret = -ENOMEM;
                goto out;
        }

        obj->gvt_info = dmabuf_obj->info;

        dmabuf = i915_gem_prime_export(&obj->base, DRM_CLOEXEC | DRM_RDWR);
        if (IS_ERR(dmabuf)) {
                gvt_vgpu_err("export dma-buf failed\n");
                ret = PTR_ERR(dmabuf);
                goto out_free_gem;
        }

        ret = dma_buf_fd(dmabuf, DRM_CLOEXEC | DRM_RDWR);
        if (ret < 0) {
                gvt_vgpu_err("create dma-buf fd failed ret:%d\n", ret);
                goto out_free_dmabuf;
        }
        dmabuf_fd = ret;

        dmabuf_obj_get(dmabuf_obj);

        if (dmabuf_obj->initref) {
                dmabuf_obj->initref = false;
                dmabuf_obj_put(dmabuf_obj);
        }

        mutex_unlock(&vgpu->dmabuf_lock);

        gvt_dbg_dpy("vgpu%d: dmabuf:%d, dmabuf ref %d, fd:%d\n"
                    "        file count: %ld, GEM ref: %d\n",
                    vgpu->id, dmabuf_obj->dmabuf_id,
                    kref_read(&dmabuf_obj->kref),
                    dmabuf_fd,
                    file_count(dmabuf->file),
                    kref_read(&obj->base.refcount));

        i915_gem_object_put(obj);

        return dmabuf_fd;

out_free_dmabuf:
        dma_buf_put(dmabuf);
out_free_gem:
        i915_gem_object_put(obj);
out:
        mutex_unlock(&vgpu->dmabuf_lock);
        return ret;
}

void intel_vgpu_dmabuf_cleanup(struct intel_vgpu *vgpu)
{
        struct list_head *pos, *n;
        struct intel_vgpu_dmabuf_obj *dmabuf_obj;

        mutex_lock(&vgpu->dmabuf_lock);
        list_for_each_safe(pos, n, &vgpu->dmabuf_obj_list_head) {
                dmabuf_obj = container_of(pos, struct intel_vgpu_dmabuf_obj,
                                                list);
                dmabuf_obj->vgpu = NULL;

                idr_remove(&vgpu->object_idr, dmabuf_obj->dmabuf_id);
                intel_gvt_hypervisor_put_vfio_device(vgpu);
                list_del(pos);

                /* dmabuf_obj might be freed in dmabuf_obj_put */
                if (dmabuf_obj->initref) {
                        dmabuf_obj->initref = false;
                        dmabuf_obj_put(dmabuf_obj);
                }

        }
        mutex_unlock(&vgpu->dmabuf_lock);
}