path: root/src/mesa/drivers/dri/i915/intel_mipmap_tree.c

/**************************************************************************
 *
 * Copyright 2006 VMware, Inc.
 * 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, sub license, 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 NON-INFRINGEMENT.
 * IN NO EVENT SHALL VMWARE AND/OR ITS SUPPLIERS 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.
 *
 **************************************************************************/

#include <GL/gl.h>
#include <GL/internal/dri_interface.h>

#include "intel_batchbuffer.h"
#include "intel_chipset.h"
#include "intel_context.h"
#include "intel_mipmap_tree.h"
#include "intel_regions.h"
#include "intel_tex_layout.h"
#include "intel_tex.h"
#include "intel_blit.h"

#include "main/enums.h"
#include "main/formats.h"
#include "main/glformats.h"
#include "main/teximage.h"

#define FILE_DEBUG_FLAG DEBUG_MIPTREE

static GLenum
target_to_target(GLenum target)
{
   switch (target) {
   case GL_TEXTURE_CUBE_MAP_POSITIVE_X_ARB:
   case GL_TEXTURE_CUBE_MAP_NEGATIVE_X_ARB:
   case GL_TEXTURE_CUBE_MAP_POSITIVE_Y_ARB:
   case GL_TEXTURE_CUBE_MAP_NEGATIVE_Y_ARB:
   case GL_TEXTURE_CUBE_MAP_POSITIVE_Z_ARB:
   case GL_TEXTURE_CUBE_MAP_NEGATIVE_Z_ARB:
      return GL_TEXTURE_CUBE_MAP_ARB;
   default:
      return target;
   }
}

struct intel_mipmap_tree *
intel_miptree_create_layout(struct intel_context *intel,
                            GLenum target,
                            mesa_format format,
                            GLuint first_level,
                            GLuint last_level,
                            GLuint width0,
                            GLuint height0,
                            GLuint depth0)
{
   struct intel_mipmap_tree *mt = calloc(sizeof(*mt), 1);
   if (!mt)
      return NULL;

   DBG("%s target %s format %s level %d..%d <-- %p\n", __func__,
       _mesa_enum_to_string(target),
       _mesa_get_format_name(format),
       first_level, last_level, mt);

   mt->target = target_to_target(target);
   mt->format = format;
   mt->first_level = first_level;
   mt->last_level = last_level;

   /* The cpp is bytes per (1, blockheight)-sized block for compressed
    * textures.  This is why you'll see divides by blockheight all over
    */
   unsigned bw, bh;
   _mesa_get_format_block_size(format, &bw, &bh);
   assert(_mesa_get_format_bytes(mt->format) % bw == 0);
   mt->cpp = _mesa_get_format_bytes(mt->format) / bw;

   mt->compressed = _mesa_is_format_compressed(format);
   mt->refcount = 1;

   if (target == GL_TEXTURE_CUBE_MAP) {
      assert(depth0 == 1);
      depth0 = 6;
   }

   mt->physical_width0 = width0;
   mt->physical_height0 = height0;
   mt->physical_depth0 = depth0;

   intel_get_texture_alignment_unit(intel, mt->format,
                                    &mt->align_w, &mt->align_h);

   if (intel->is_945)
      i945_miptree_layout(mt);
   else
      i915_miptree_layout(mt);

   return mt;
}

/**
 * \brief Helper function for intel_miptree_create().
 */
static uint32_t
intel_miptree_choose_tiling(struct intel_context *intel,
                            mesa_format format,
                            uint32_t width0,
                            enum intel_miptree_tiling_mode requested,
                            struct intel_mipmap_tree *mt)
{
   /* Some usages may want only one type of tiling, like depth miptrees (Y
    * tiled), or temporary BOs for uploading data once (linear).
    */
   switch (requested) {
   case INTEL_MIPTREE_TILING_ANY:
      break;
   case INTEL_MIPTREE_TILING_Y:
      return I915_TILING_Y;
   case INTEL_MIPTREE_TILING_NONE:
      return I915_TILING_NONE;
   }

   int minimum_pitch = mt->total_width * mt->cpp;

   /* If the width is much smaller than a tile, don't bother tiling. */
   if (minimum_pitch < 64)
      return I915_TILING_NONE;

   if (ALIGN(minimum_pitch, 512) >= 32768) {
      perf_debug("%dx%d miptree too large to blit, falling back to untiled",
                 mt->total_width, mt->total_height);
      return I915_TILING_NONE;
   }

   /* We don't have BLORP to handle Y-tiled blits, so use X-tiling. */
   return I915_TILING_X;
}

struct intel_mipmap_tree *
intel_miptree_create(struct intel_context *intel,
                     GLenum target,
                     mesa_format format,
                     GLuint first_level,
                     GLuint last_level,
                     GLuint width0,
                     GLuint height0,
                     GLuint depth0,
                     bool expect_accelerated_upload,
                     enum intel_miptree_tiling_mode requested_tiling)
{
   struct intel_mipmap_tree *mt;
   GLuint total_width, total_height;


   mt = intel_miptree_create_layout(intel, target, format,
                                    first_level, last_level, width0,
                                    height0, depth0);

   /* pitch == 0 || height == 0  indicates the null texture */
   if (!mt || !mt->total_width || !mt->total_height) {
      intel_miptree_release(&mt);
      return NULL;
   }

   total_width = mt->total_width;
   total_height = mt->total_height;

   uint32_t tiling = intel_miptree_choose_tiling(intel, format, width0,
                                                 requested_tiling,
                                                 mt);
   bool y_or_x = tiling == (I915_TILING_Y | I915_TILING_X);

   mt->region = intel_region_alloc(intel->intelScreen,
                                   y_or_x ? I915_TILING_Y : tiling,
                                   mt->cpp,
                                   total_width,
                                   total_height,
                                   expect_accelerated_upload);

   /* If the region is too large to fit in the aperture, we need to use the
    * BLT engine to support it.  The BLT paths can't currently handle Y-tiling,
    * so we need to fall back to X.
    */
   if (y_or_x && mt->region->bo->size >= intel->max_gtt_map_object_size) {
      perf_debug("%dx%d miptree larger than aperture; falling back to X-tiled\n",
                 mt->total_width, mt->total_height);
      intel_region_release(&mt->region);

      mt->region = intel_region_alloc(intel->intelScreen,
                                      I915_TILING_X,
                                      mt->cpp,
                                      total_width,
                                      total_height,
                                      expect_accelerated_upload);
   }

   mt->offset = 0;

   if (!mt->region) {
       intel_miptree_release(&mt);
       return NULL;
   }

   return mt;
}

struct intel_mipmap_tree *
intel_miptree_create_for_bo(struct intel_context *intel,
                            drm_intel_bo *bo,
                            mesa_format format,
                            uint32_t offset,
                            uint32_t width,
                            uint32_t height,
                            int pitch,
                            uint32_t tiling)
{
   struct intel_mipmap_tree *mt;

   struct intel_region *region = calloc(1, sizeof(*region));
   if (!region)
      return NULL;

   /* Nothing will be able to use this miptree with the BO if the offset isn't
    * aligned.
    */
   if (tiling != I915_TILING_NONE)
      assert(offset % 4096 == 0);

   /* miptrees can't handle negative pitch.  If you need flipping of images,
    * that's outside of the scope of the mt.
    */
   assert(pitch >= 0);

   mt = intel_miptree_create_layout(intel, GL_TEXTURE_2D, format,
                                    0, 0,
                                    width, height, 1);
   if (!mt) {
      free(region);
      return mt;
   }

   region->cpp = mt->cpp;
   region->width = width;
   region->height = height;
   region->pitch = pitch;
   region->refcount = 1;
   drm_intel_bo_reference(bo);
   region->bo = bo;
   region->tiling = tiling;

   mt->region = region;
   mt->offset = offset;

   return mt;
}


/**
 * Wraps the given region with a miptree.
 */
struct intel_mipmap_tree *
intel_miptree_create_for_dri2_buffer(struct intel_context *intel,
                                     unsigned dri_attachment,
                                     mesa_format format,
                                     struct intel_region *region)
{
   struct intel_mipmap_tree *mt = NULL;

   /* Only the front and back buffers, which are color buffers, are shared
    * through DRI2.
    */
   assert(dri_attachment == __DRI_BUFFER_BACK_LEFT ||
          dri_attachment == __DRI_BUFFER_FRONT_LEFT ||
          dri_attachment == __DRI_BUFFER_FAKE_FRONT_LEFT);
   assert(_mesa_get_format_base_format(format) == GL_RGB ||
          _mesa_get_format_base_format(format) == GL_RGBA);

   mt = intel_miptree_create_for_bo(intel,
                                    region->bo,
                                    format,
                                    0,
                                    region->width,
                                    region->height,
                                    region->pitch,
                                    region->tiling);
   if (!mt)
      return NULL;
   mt->region->name = region->name;

   return mt;
}

/**
 * Wraps the given region with a miptree.
 */
struct intel_mipmap_tree *
intel_miptree_create_for_image_buffer(struct intel_context *intel,
                                      enum __DRIimageBufferMask buffer_type,
                                      mesa_format format,
                                      uint32_t num_samples,
                                      struct intel_region *region)
{
   struct intel_mipmap_tree *mt = NULL;

   /* Only the front and back buffers, which are color buffers, are allocated
    * through the image loader.
    */
   assert(_mesa_get_format_base_format(format) == GL_RGB ||
          _mesa_get_format_base_format(format) == GL_RGBA);

   mt = intel_miptree_create_for_bo(intel,
                                    region->bo,
                                    format,
                                    0,
                                    region->width,
                                    region->height,
                                    region->pitch,
                                    region->tiling);
   return mt;
}

struct intel_mipmap_tree *
intel_miptree_create_for_renderbuffer(struct intel_context *intel,
                                      mesa_format format,
                                      uint32_t width,
                                      uint32_t height)
{
   uint32_t depth = 1;

   return intel_miptree_create(intel, GL_TEXTURE_2D, format, 0, 0,
                               width, height, depth, true,
                               INTEL_MIPTREE_TILING_ANY);
}

void
intel_miptree_reference(struct intel_mipmap_tree **dst,
                        struct intel_mipmap_tree *src)
{
   if (*dst == src)
      return;

   intel_miptree_release(dst);

   if (src) {
      src->refcount++;
      DBG("%s %p refcount now %d\n", __func__, src, src->refcount);
   }

   *dst = src;
}


void
intel_miptree_release(struct intel_mipmap_tree **mt)
{
   if (!*mt)
      return;

   DBG("%s %p refcount will be %d\n", __func__, *mt, (*mt)->refcount - 1);
   if (--(*mt)->refcount <= 0) {
      GLuint i;

      DBG("%s deleting %p\n", __func__, *mt);

      intel_region_release(&((*mt)->region));

      for (i = 0; i < MAX_TEXTURE_LEVELS; i++) {
         free((*mt)->level[i].slice);
      }

      free(*mt);
   }
   *mt = NULL;
}

void
intel_miptree_get_dimensions_for_image(struct gl_texture_image *image,
                                       int *width, int *height, int *depth)
{
   switch (image->TexObject->Target) {
   default:
      *width = image->Width;
      *height = image->Height;
      *depth = image->Depth;
      break;
   }
}

/**
 * Can the image be pulled into a unified mipmap tree?  This mirrors
 * the completeness test in a lot of ways.
 *
 * Not sure whether I want to pass gl_texture_image here.
 */
bool
intel_miptree_match_image(struct intel_mipmap_tree *mt,
                          struct gl_texture_image *image)
{
   struct intel_texture_image *intelImage = intel_texture_image(image);
   GLuint level = intelImage->base.Base.Level;
   int width, height, depth;

   /* glTexImage* choose the texture object based on the target passed in, and
    * objects can't change targets over their lifetimes, so this should be
    * true.
    */
   assert(target_to_target(image->TexObject->Target) == mt->target);

   mesa_format mt_format = mt->format;

   if (image->TexFormat != mt_format)
      return false;

   intel_miptree_get_dimensions_for_image(image, &width, &height, &depth);

   if (mt->target == GL_TEXTURE_CUBE_MAP)
      depth = 6;

   /* Test image dimensions against the base level image adjusted for
    * minification.  This will also catch images not present in the
    * tree, changed targets, etc.
    */
   if (width != mt->level[level].width ||
       height != mt->level[level].height ||
       depth != mt->level[level].depth) {
      return false;
   }

   return true;
}


void
intel_miptree_set_level_info(struct intel_mipmap_tree *mt,
                             GLuint level,
                             GLuint x, GLuint y,
                             GLuint w, GLuint h, GLuint d)
{
   mt->level[level].width = w;
   mt->level[level].height = h;
   mt->level[level].depth = d;
   mt->level[level].level_x = x;
   mt->level[level].level_y = y;

   DBG("%s level %d size: %d,%d,%d offset %d,%d\n", __func__,
       level, w, h, d, x, y);

   assert(mt->level[level].slice == NULL);

   mt->level[level].slice = calloc(d, sizeof(*mt->level[0].slice));
   mt->level[level].slice[0].x_offset = mt->level[level].level_x;
   mt->level[level].slice[0].y_offset = mt->level[level].level_y;
}


void
intel_miptree_set_image_offset(struct intel_mipmap_tree *mt,
                               GLuint level, GLuint img,
                               GLuint x, GLuint y)
{
   if (img == 0 && level == 0)
      assert(x == 0 && y == 0);

   assert(img < mt->level[level].depth);

   mt->level[level].slice[img].x_offset = mt->level[level].level_x + x;
   mt->level[level].slice[img].y_offset = mt->level[level].level_y + y;

   DBG("%s level %d img %d pos %d,%d\n",
       __func__, level, img,
       mt->level[level].slice[img].x_offset,
       mt->level[level].slice[img].y_offset);
}

void
intel_miptree_get_image_offset(struct intel_mipmap_tree *mt,
                               GLuint level, GLuint slice,
                               GLuint *x, GLuint *y)
{
   assert(slice < mt->level[level].depth);

   *x = mt->level[level].slice[slice].x_offset;
   *y = mt->level[level].slice[slice].y_offset;
}

/**
 * Rendering with tiled buffers requires that the base address of the buffer
 * be aligned to a page boundary.  For renderbuffers, and sometimes with
 * textures, we may want the surface to point at a texture image level that
 * isn't at a page boundary.
 *
 * This function returns an appropriately-aligned base offset
 * according to the tiling restrictions, plus any required x/y offset
 * from there.
 */
uint32_t
intel_miptree_get_tile_offsets(struct intel_mipmap_tree *mt,
                               GLuint level, GLuint slice,
                               uint32_t *tile_x,
                               uint32_t *tile_y)
{
   struct intel_region *region = mt->region;
   uint32_t x, y;
   uint32_t mask_x, mask_y;

   intel_region_get_tile_masks(region, &mask_x, &mask_y);
   intel_miptree_get_image_offset(mt, level, slice, &x, &y);

   *tile_x = x & mask_x;
   *tile_y = y & mask_y;

   return intel_region_get_aligned_offset(region, x & ~mask_x, y & ~mask_y);
}

static void
intel_miptree_copy_slice_sw(struct intel_context *intel,
                            struct intel_mipmap_tree *dst_mt,
                            struct intel_mipmap_tree *src_mt,
                            int level,
                            int slice,
                            int width,
                            int height)
{
   void *src, *dst;
   int src_stride, dst_stride;
   int cpp = dst_mt->cpp;

   intel_miptree_map(intel, src_mt,
                     level, slice,
                     0, 0,
                     width, height,
                     GL_MAP_READ_BIT,
                     &src, &src_stride);

   intel_miptree_map(intel, dst_mt,
                     level, slice,
                     0, 0,
                     width, height,
                     GL_MAP_WRITE_BIT | GL_MAP_INVALIDATE_RANGE_BIT,
                     &dst, &dst_stride);

   DBG("sw blit %s mt %p %p/%d -> %s mt %p %p/%d (%dx%d)\n",
       _mesa_get_format_name(src_mt->format),
       src_mt, src, src_stride,
       _mesa_get_format_name(dst_mt->format),
       dst_mt, dst, dst_stride,
       width, height);

   int row_size = cpp * width;
   if (src_stride == row_size &&
       dst_stride == row_size) {
      memcpy(dst, src, row_size * height);
   } else {
      for (int i = 0; i < height; i++) {
         memcpy(dst, src, row_size);
         dst += dst_stride;
         src += src_stride;
      }
   }

   intel_miptree_unmap(intel, dst_mt, level, slice);
   intel_miptree_unmap(intel, src_mt, level, slice);
}

static void
intel_miptree_copy_slice(struct intel_context *intel,
                         struct intel_mipmap_tree *dst_mt,
                         struct intel_mipmap_tree *src_mt,
                         int level,
                         int face,
                         int depth)

{
   mesa_format format = src_mt->format;
   uint32_t width = src_mt->level[level].width;
   uint32_t height = src_mt->level[level].height;
   int slice;

   if (face > 0)
      slice = face;
   else
      slice = depth;

   assert(depth < src_mt->level[level].depth);
   assert(src_mt->format == dst_mt->format);

   if (dst_mt->compressed) {
      height = ALIGN(height, dst_mt->align_h) / dst_mt->align_h;
      width = ALIGN(width, dst_mt->align_w);
   }

   uint32_t dst_x, dst_y, src_x, src_y;
   intel_miptree_get_image_offset(dst_mt, level, slice, &dst_x, &dst_y);
   intel_miptree_get_image_offset(src_mt, level, slice, &src_x, &src_y);

   DBG("validate blit mt %s %p %d,%d/%d -> mt %s %p %d,%d/%d (%dx%d)\n",
       _mesa_get_format_name(src_mt->format),
       src_mt, src_x, src_y, src_mt->region->pitch,
       _mesa_get_format_name(dst_mt->format),
       dst_mt, dst_x, dst_y, dst_mt->region->pitch,
       width, height);

   if (!intel_miptree_blit(intel,
                           src_mt, level, slice, 0, 0, false,
                           dst_mt, level, slice, 0, 0, false,
                           width, height, GL_COPY)) {
      perf_debug("miptree validate blit for %s failed\n",
                 _mesa_get_format_name(format));

      intel_miptree_copy_slice_sw(intel, dst_mt, src_mt, level, slice,
                                  width, height);
   }
}

/**
 * Copies the image's current data to the given miptree, and associates that
 * miptree with the image.
 *
 * If \c invalidate is true, then the actual image data does not need to be
 * copied, but the image still needs to be associated to the new miptree (this
 * is set to true if we're about to clear the image).
 */
void
intel_miptree_copy_teximage(struct intel_context *intel,
                            struct intel_texture_image *intelImage,
                            struct intel_mipmap_tree *dst_mt,
                            bool invalidate)
{
   struct intel_mipmap_tree *src_mt = intelImage->mt;
   struct intel_texture_object *intel_obj =
      intel_texture_object(intelImage->base.Base.TexObject);
   int level = intelImage->base.Base.Level;
   int face = intelImage->base.Base.Face;
   GLuint depth = intelImage->base.Base.Depth;

   if (!invalidate) {
      for (int slice = 0; slice < depth; slice++) {
         intel_miptree_copy_slice(intel, dst_mt, src_mt, level, face, slice);
      }
   }

   intel_miptree_reference(&intelImage->mt, dst_mt);
   intel_obj->needs_validate = true;
}

void *
intel_miptree_map_raw(struct intel_context *intel, struct intel_mipmap_tree *mt)
{
   drm_intel_bo *bo = mt->region->bo;

   if (unlikely(INTEL_DEBUG & DEBUG_PERF)) {
      if (drm_intel_bo_busy(bo)) {
         perf_debug("Mapping a busy BO, causing a stall on the GPU.\n");
      }
   }

   intel_flush(&intel->ctx);

   if (mt->region->tiling != I915_TILING_NONE)
      drm_intel_gem_bo_map_gtt(bo);
   else
      drm_intel_bo_map(bo, true);

   return bo->virtual;
}

void
intel_miptree_unmap_raw(struct intel_mipmap_tree *mt)
{
   drm_intel_bo_unmap(mt->region->bo);
}

static void
intel_miptree_map_gtt(struct intel_context *intel,
                      struct intel_mipmap_tree *mt,
                      struct intel_miptree_map *map,
                      unsigned int level, unsigned int slice)
{
   unsigned int bw, bh;
   void *base;
   unsigned int image_x, image_y;
   int x = map->x;
   int y = map->y;

   /* For compressed formats, the stride is the number of bytes per
    * row of blocks.  intel_miptree_get_image_offset() already does
    * the divide.
    */
   _mesa_get_format_block_size(mt->format, &bw, &bh);
   assert(y % bh == 0);
   y /= bh;

   base = intel_miptree_map_raw(intel, mt) + mt->offset;

   if (base == NULL)
      map->ptr = NULL;
   else {
      /* Note that in the case of cube maps, the caller must have passed the
       * slice number referencing the face.
      */
      intel_miptree_get_image_offset(mt, level, slice, &image_x, &image_y);
      x += image_x;
      y += image_y;

      map->stride = mt->region->pitch;
      map->ptr = base + y * map->stride + x * mt->cpp;
   }

   DBG("%s: %d,%d %dx%d from mt %p (%s) %d,%d = %p/%d\n", __func__,
       map->x, map->y, map->w, map->h,
       mt, _mesa_get_format_name(mt->format),
       x, y, map->ptr, map->stride);
}

static void
intel_miptree_unmap_gtt(struct intel_mipmap_tree *mt)
{
   intel_miptree_unmap_raw(mt);
}

static void
intel_miptree_map_blit(struct intel_context *intel,
                       struct intel_mipmap_tree *mt,
                       struct intel_miptree_map *map,
                       unsigned int level, unsigned int slice)
{
   map->mt = intel_miptree_create(intel, GL_TEXTURE_2D, mt->format,
                                  0, 0,
                                  map->w, map->h, 1,
                                  false,
                                  INTEL_MIPTREE_TILING_NONE);
   if (!map->mt) {
      fprintf(stderr, "Failed to allocate blit temporary\n");
      goto fail;
   }
   map->stride = map->mt->region->pitch;

   if (!intel_miptree_blit(intel,
                           mt, level, slice,
                           map->x, map->y, false,
                           map->mt, 0, 0,
                           0, 0, false,
                           map->w, map->h, GL_COPY)) {
      fprintf(stderr, "Failed to blit\n");
      goto fail;
   }

   intel_batchbuffer_flush(intel);
   map->ptr = intel_miptree_map_raw(intel, map->mt);

   DBG("%s: %d,%d %dx%d from mt %p (%s) %d,%d = %p/%d\n", __func__,
       map->x, map->y, map->w, map->h,
       mt, _mesa_get_format_name(mt->format),
       level, slice, map->ptr, map->stride);

   return;

fail:
   intel_miptree_release(&map->mt);
   map->ptr = NULL;
   map->stride = 0;
}

static void
intel_miptree_unmap_blit(struct intel_context *intel,
                         struct intel_mipmap_tree *mt,
                         struct intel_miptree_map *map,
                         unsigned int level,
                         unsigned int slice)
{
   struct gl_context *ctx = &intel->ctx;

   intel_miptree_unmap_raw(map->mt);

   if (map->mode & GL_MAP_WRITE_BIT) {
      bool ok = intel_miptree_blit(intel,
                                   map->mt, 0, 0,
                                   0, 0, false,
                                   mt, level, slice,
                                   map->x, map->y, false,
                                   map->w, map->h, GL_COPY);
      WARN_ONCE(!ok, "Failed to blit from linear temporary mapping");
   }

   intel_miptree_release(&map->mt);
}

/**
 * Create and attach a map to the miptree at (level, slice). Return the
 * attached map.
 */
static struct intel_miptree_map*
intel_miptree_attach_map(struct intel_mipmap_tree *mt,
                         unsigned int level,
                         unsigned int slice,
                         unsigned int x,
                         unsigned int y,
                         unsigned int w,
                         unsigned int h,
                         GLbitfield mode)
{
   struct intel_miptree_map *map = calloc(1, sizeof(*map));

   if (!map)
      return NULL;

   assert(mt->level[level].slice[slice].map == NULL);
   mt->level[level].slice[slice].map = map;

   map->mode = mode;
   map->x = x;
   map->y = y;
   map->w = w;
   map->h = h;

   return map;
}

/**
 * Release the map at (level, slice).
 */
static void
intel_miptree_release_map(struct intel_mipmap_tree *mt,
                         unsigned int level,
                         unsigned int slice)
{
   struct intel_miptree_map **map;

   map = &mt->level[level].slice[slice].map;
   free(*map);
   *map = NULL;
}

void
intel_miptree_map(struct intel_context *intel,
                  struct intel_mipmap_tree *mt,
                  unsigned int level,
                  unsigned int slice,
                  unsigned int x,
                  unsigned int y,
                  unsigned int w,
                  unsigned int h,
                  GLbitfield mode,
                  void **out_ptr,
                  int *out_stride)
{
   struct intel_miptree_map *map;

   map = intel_miptree_attach_map(mt, level, slice, x, y, w, h, mode);
   if (!map) {
      *out_ptr = NULL;
      *out_stride = 0;
      return;
   }

   /* See intel_miptree_blit() for details on the 32k pitch limit. */
   if (mt->region->tiling != I915_TILING_NONE &&
       mt->region->bo->size >= intel->max_gtt_map_object_size) {
      assert(mt->region->pitch < 32768);
      intel_miptree_map_blit(intel, mt, map, level, slice);
   } else {
      intel_miptree_map_gtt(intel, mt, map, level, slice);
   }

   *out_ptr = map->ptr;
   *out_stride = map->stride;

   if (map->ptr == NULL)
      intel_miptree_release_map(mt, level, slice);
}

void
intel_miptree_unmap(struct intel_context *intel,
                    struct intel_mipmap_tree *mt,
                    unsigned int level,
                    unsigned int slice)
{
   struct intel_miptree_map *map = mt->level[level].slice[slice].map;

   if (!map)
      return;

   DBG("%s: mt %p (%s) level %d slice %d\n", __func__,
       mt, _mesa_get_format_name(mt->format), level, slice);

   if (map->mt) {
      intel_miptree_unmap_blit(intel, mt, map, level, slice);
   } else {
      intel_miptree_unmap_gtt(mt);
   }

   intel_miptree_release_map(mt, level, slice);
}