/*
 * Copyright © 2014 Broadcom
 *
 * 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.
 */

/** @file vc4_tiling.c
 *
 * Handles information about the VC4 tiling formats, and loading and storing
 * from them.
 *
 * Texture mipmap levels on VC4 are (with the exception of 32-bit RGBA raster
 * textures for scanout) stored as groups of microtiles.  If the texture is at
 * least 4x4 microtiles (utiles), then those microtiles are arranged in a sort
 * of Hilbert-fractal-ish layout (T), otherwise the microtiles are in raster
 * order (LT).
 *
 * Specifically, the T format has:
 *
 * - 64b utiles of pixels in a raster-order grid according to cpp.  It's 4x4
 *   pixels at 32 bit depth.
 *
 * - 1k subtiles made of a 4x4 raster-order grid of 64b utiles (so usually
 *   16x16 pixels).
 *
 * - 4k tiles made of a 2x2 grid of 1k subtiles (so usually 32x32 pixels).  On
 *   even 4k tile rows, they're arranged as (BL, TL, TR, BR), and on odd rows
 *   they're (TR, BR, BL, TL), where bottom left is start of memory.
 *
 * - an image made of 4k tiles in rows either left-to-right (even rows of 4k
 *   tiles) or right-to-left (odd rows of 4k tiles).
 */

#include "vc4_screen.h"
#include "vc4_context.h"
#include "vc4_tiling.h"

/**
 * The texture unit decides what tiling format a particular miplevel is using
 * this function, so we lay out our miptrees accordingly.
 */
bool
vc4_size_is_lt(uint32_t width, uint32_t height, int cpp)
{
        return (width <= 4 * vc4_utile_width(cpp) ||
                height <= 4 * vc4_utile_height(cpp));
}

static void
check_box_utile_alignment(const struct pipe_box *box, int cpp)
{
        assert(!(box->x & (vc4_utile_width(cpp) - 1)));
        assert(!(box->y & (vc4_utile_height(cpp) - 1)));
        assert(!(box->width & (vc4_utile_width(cpp) - 1)));
        assert(!(box->height & (vc4_utile_height(cpp) - 1)));
}

/**
 * Takes a utile x and y (and the number of utiles of width of the image) and
 * returns the offset to the utile within a VC4_TILING_FORMAT_TF image.
 */
static uint32_t
t_utile_address(uint32_t utile_x, uint32_t utile_y,
                uint32_t utile_stride)
{
        /* T images have to be aligned to 8 utiles (4x4 subtiles, which are
         * 2x2 in a 4k tile).
         */
        assert(!(utile_stride & 7));
        uint32_t tile_stride = utile_stride >> 3;
        /* 4k tile offsets. */
        uint32_t tile_x = utile_x >> 3;
        uint32_t tile_y = utile_y >> 3;
        bool odd_tile_y = tile_y & 1;

        /* Odd lines of 4k tiles go right-to-left. */
        if (odd_tile_y)
                tile_x = tile_stride - tile_x - 1;

        uint32_t tile_offset = 4096 * (tile_y * tile_stride + tile_x);

        uint32_t stile_x = (utile_x >> 2) & 1;
        uint32_t stile_y = (utile_y >> 2) & 1;
        uint32_t stile_index = (stile_y << 1) + stile_x;
        static const uint32_t odd_stile_map[4] = {2, 1, 3, 0};
        static const uint32_t even_stile_map[4] = {0, 3, 1, 2};

        uint32_t stile_offset = 1024 * (odd_tile_y ?
                                        odd_stile_map[stile_index] :
                                        even_stile_map[stile_index]);

        /* This function no longer handles the utile offset within a subtile.
         * Walking subtiles is the job of the LT image handler.
         */
        assert(!(utile_x & 3) && !(utile_y & 3));

#if 0
        fprintf(stderr, "utile %d,%d -> %d + %d + %d (stride %d,%d) = %d\n",
                utile_x, utile_y,
                tile_offset, stile_offset, utile_offset,
                utile_stride, tile_stride,
                tile_offset + stile_offset + utile_offset);
#endif

        return tile_offset + stile_offset;
}

/**
 * Loads or stores a T texture image by breaking it down into subtiles
 * (1024-byte, 4x4-utile) sub-images that we can use the LT tiling functions
 * on.
 */
static inline void
vc4_t_image_helper(void *gpu, uint32_t gpu_stride,
                   void *cpu, uint32_t cpu_stride,
                   int cpp, const struct pipe_box *box,
                   bool to_cpu)
{
        uint32_t utile_w = vc4_utile_width(cpp);
        uint32_t utile_h = vc4_utile_height(cpp);
        uint32_t utile_w_shift = ffs(utile_w) - 1;
        uint32_t utile_h_shift = ffs(utile_h) - 1;
        uint32_t stile_w = 4 * utile_w;
        uint32_t stile_h = 4 * utile_h;
        assert(stile_w * stile_h * cpp == 1024);
        uint32_t utile_stride = gpu_stride / cpp / utile_w;
        uint32_t x1 = box->x;
        uint32_t y1 = box->y;
        uint32_t x2 = box->x + box->width;
        uint32_t y2 = box->y + box->height;
        struct pipe_box partial_box;
        uint32_t gpu_lt_stride = stile_w * cpp;

        for (uint32_t y = y1; y < y2; y = align(y + 1, stile_h)) {
                partial_box.y = y & (stile_h - 1);
                partial_box.height = MIN2(y2 - y, stile_h - partial_box.y);

                uint32_t cpu_offset = 0;
                for (uint32_t x = x1; x < x2; x = align(x + 1, stile_w)) {
                        partial_box.x = x & (stile_w - 1);
                        partial_box.width = MIN2(x2 - x,
                                                 stile_w - partial_box.x);

                        /* The dst offset we want is the start of this
                         * subtile
                         */
                        uint32_t gpu_offset =
                                t_utile_address((x >> utile_w_shift) & ~0x3,
                                                (y >> utile_h_shift) & ~0x3,
                                                utile_stride);

                        if (to_cpu) {
                                vc4_load_lt_image(cpu + cpu_offset,
                                                  cpu_stride,
                                                  gpu + gpu_offset,
                                                  gpu_lt_stride,
                                                  cpp, &partial_box);
                        } else {
                                vc4_store_lt_image(gpu + gpu_offset,
                                                   gpu_lt_stride,
                                                   cpu + cpu_offset,
                                                   cpu_stride,
                                                   cpp, &partial_box);
                        }

                        cpu_offset += partial_box.width * cpp;
                }
                cpu += cpu_stride * partial_box.height;
        }
}

static void
vc4_store_t_image(void *dst, uint32_t dst_stride,
                  void *src, uint32_t src_stride,
                  int cpp, const struct pipe_box *box)
{
        vc4_t_image_helper(dst, dst_stride,
                           src, src_stride,
                           cpp, box, false);
}

static void
vc4_load_t_image(void *dst, uint32_t dst_stride,
                  void *src, uint32_t src_stride,
                  int cpp, const struct pipe_box *box)
{
        vc4_t_image_helper(src, src_stride,
                           dst, dst_stride,
                           cpp, box, true);
}

/**
 * Loads pixel data from the start (microtile-aligned) box in \p src to the
 * start of \p dst according to the given tiling format.
 */
void
vc4_load_tiled_image(void *dst, uint32_t dst_stride,
                     void *src, uint32_t src_stride,
                     uint8_t tiling_format, int cpp,
                     const struct pipe_box *box)
{
        check_box_utile_alignment(box, cpp);

        if (tiling_format == VC4_TILING_FORMAT_LT) {
                vc4_load_lt_image(dst, dst_stride,
                                  src, src_stride,
                                  cpp, box);
        } else {
                assert(tiling_format == VC4_TILING_FORMAT_T);
                vc4_load_t_image(dst, dst_stride,
                                 src, src_stride,
                                 cpp, box);
        }
}

/**
 * Stores pixel data from the start of \p src into a (microtile-aligned) box in
 * \p dst according to the given tiling format.
 */
void
vc4_store_tiled_image(void *dst, uint32_t dst_stride,
                      void *src, uint32_t src_stride,
                      uint8_t tiling_format, int cpp,
                      const struct pipe_box *box)
{
        check_box_utile_alignment(box, cpp);

        if (tiling_format == VC4_TILING_FORMAT_LT) {
                vc4_store_lt_image(dst, dst_stride,
                                   src, src_stride,
                                   cpp, box);
        } else {
                assert(tiling_format == VC4_TILING_FORMAT_T);
                vc4_store_t_image(dst, dst_stride,
                                  src, src_stride,
                                  cpp, box);
        }
}

