1 /* 2 * Copyright (C) 2019 Collabora, Ltd. 3 * 4 * Permission is hereby granted, free of charge, to any person obtaining a 5 * copy of this software and associated documentation files (the "Software"), 6 * to deal in the Software without restriction, including without limitation 7 * the rights to use, copy, modify, merge, publish, distribute, sublicense, 8 * and/or sell copies of the Software, and to permit persons to whom the 9 * Software is furnished to do so, subject to the following conditions: 10 * 11 * The above copyright notice and this permission notice (including the next 12 * paragraph) shall be included in all copies or substantial portions of the 13 * Software. 14 * 15 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 16 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 17 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL 18 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 19 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, 20 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE 21 * SOFTWARE. 22 * 23 * Authors: 24 * Alyssa Rosenzweig <alyssa.rosenzweig (at) collabora.com> 25 */ 26 27 #include "pan_texture.h" 28 29 /* Arm FrameBuffer Compression (AFBC) is a lossless compression scheme natively 30 * implemented in Mali GPUs (as well as many display controllers paired with 31 * Mali GPUs, etc). Where possible, Panfrost prefers to use AFBC for both 32 * rendering and texturing. In most cases, this is a performance-win due to a 33 * dramatic reduction in memory bandwidth and cache locality compared to a 34 * linear resources. 35 * 36 * AFBC divides the framebuffer into 16x16 tiles (other sizes possible, TODO: 37 * do we need to support this?). So, the width and height each must be aligned 38 * up to 16 pixels. This is inherently good for performance; note that for a 4 39 * byte-per-pixel format like RGBA8888, that means that rows are 16*4=64 byte 40 * aligned, which is the cache-line size. 41 * 42 * For each AFBC-compressed resource, there is a single contiguous 43 * (CPU/GPU-shared) buffer. This buffer itself is divided into two parts: 44 * header and body, placed immediately after each other. 45 * 46 * The AFBC header contains 16 bytes of metadata per tile. 47 * 48 * The AFBC body is the same size as the original linear resource (padded to 49 * the nearest tile). Although the body comes immediately after the header, it 50 * must also be cache-line aligned, so there can sometimes be a bit of padding 51 * between the header and body. 52 * 53 * As an example, a 64x64 RGBA framebuffer contains 64/16 = 4 tiles horizontally and 54 * 4 tiles vertically. There are 4*4=16 tiles in total, each containing 16 55 * bytes of metadata, so there is a 16*16=256 byte header. 64x64 is already 56 * tile aligned, so the body is 64*64 * 4 bytes per pixel = 16384 bytes of 57 * body. 58 * 59 * From userspace, Panfrost needs to be able to calculate these sizes. It 60 * explicitly does not and can not know the format of the data contained within 61 * this header and body. The GPU has native support for AFBC encode/decode. For 62 * an internal FBO or a framebuffer used for scanout with an AFBC-compatible 63 * winsys/display-controller, the buffer is maintained AFBC throughout flight, 64 * and the driver never needs to know the internal data. For edge cases where 65 * the driver really does need to read/write from the AFBC resource, we 66 * generate a linear staging buffer and use the GPU to blit AFBC<--->linear. 67 * TODO: Implement me. */ 68 69 #define AFBC_TILE_WIDTH 16 70 #define AFBC_TILE_HEIGHT 16 71 #define AFBC_CACHE_ALIGN 64 72 73 /* AFBC supports compressing a few canonical formats. Additional formats are 74 * available by using a canonical internal format. Given a PIPE format, find 75 * the canonical AFBC internal format if it exists, or NONE if the format 76 * cannot be compressed. */ 77 78 enum pipe_format 79 panfrost_afbc_format(const struct panfrost_device *dev, enum pipe_format format) 80 { 81 /* Don't allow swizzled formats on v7 */ 82 switch (format) { 83 case PIPE_FORMAT_B8G8R8A8_UNORM: 84 case PIPE_FORMAT_B8G8R8X8_UNORM: 85 case PIPE_FORMAT_A8R8G8B8_UNORM: 86 case PIPE_FORMAT_X8R8G8B8_UNORM: 87 case PIPE_FORMAT_X8B8G8R8_UNORM: 88 case PIPE_FORMAT_A8B8G8R8_UNORM: 89 case PIPE_FORMAT_B8G8R8_UNORM: 90 case PIPE_FORMAT_B5G6R5_UNORM: 91 if (dev->arch >= 7) 92 return PIPE_FORMAT_NONE; 93 94 break; 95 default: 96 break; 97 } 98 99 switch (format) { 100 case PIPE_FORMAT_Z16_UNORM: 101 return PIPE_FORMAT_R8G8_UNORM; 102 103 case PIPE_FORMAT_R8G8B8_UNORM: 104 case PIPE_FORMAT_B8G8R8_UNORM: 105 return PIPE_FORMAT_R8G8B8_UNORM; 106 107 case PIPE_FORMAT_R8G8B8A8_UNORM: 108 case PIPE_FORMAT_R8G8B8X8_UNORM: 109 case PIPE_FORMAT_Z24_UNORM_S8_UINT: 110 case PIPE_FORMAT_Z24X8_UNORM: 111 case PIPE_FORMAT_X24S8_UINT: 112 case PIPE_FORMAT_B8G8R8A8_UNORM: 113 case PIPE_FORMAT_B8G8R8X8_UNORM: 114 case PIPE_FORMAT_A8R8G8B8_UNORM: 115 case PIPE_FORMAT_X8R8G8B8_UNORM: 116 case PIPE_FORMAT_X8B8G8R8_UNORM: 117 case PIPE_FORMAT_A8B8G8R8_UNORM: 118 return PIPE_FORMAT_R8G8B8A8_UNORM; 119 120 case PIPE_FORMAT_R5G6B5_UNORM: 121 case PIPE_FORMAT_B5G6R5_UNORM: 122 return PIPE_FORMAT_R5G6B5_UNORM; 123 124 /* TODO: More AFBC formats */ 125 default: 126 return PIPE_FORMAT_NONE; 127 } 128 } 129 130 /* A format may be compressed as AFBC if it has an AFBC internal format */ 131 132 bool 133 panfrost_format_supports_afbc(const struct panfrost_device *dev, enum pipe_format format) 134 { 135 return panfrost_afbc_format(dev, format) != PIPE_FORMAT_NONE; 136 } 137 138 unsigned 139 panfrost_afbc_header_size(unsigned width, unsigned height) 140 { 141 /* Align to tile */ 142 unsigned aligned_width = ALIGN_POT(width, AFBC_TILE_WIDTH); 143 unsigned aligned_height = ALIGN_POT(height, AFBC_TILE_HEIGHT); 144 145 /* Compute size in tiles, rather than pixels */ 146 unsigned tile_count_x = aligned_width / AFBC_TILE_WIDTH; 147 unsigned tile_count_y = aligned_height / AFBC_TILE_HEIGHT; 148 unsigned tile_count = tile_count_x * tile_count_y; 149 150 /* Multiply to find the header size */ 151 unsigned header_bytes = tile_count * AFBC_HEADER_BYTES_PER_TILE; 152 153 /* Align and go */ 154 return ALIGN_POT(header_bytes, AFBC_CACHE_ALIGN); 155 156 } 157 158 /* The lossless colour transform (AFBC_FORMAT_MOD_YTR) requires RGB. */ 159 160 bool 161 panfrost_afbc_can_ytr(enum pipe_format format) 162 { 163 const struct util_format_description *desc = 164 util_format_description(format); 165 166 /* YTR is only defined for RGB(A) */ 167 if (desc->nr_channels != 3 && desc->nr_channels != 4) 168 return false; 169 170 /* The fourth channel if it exists doesn't matter */ 171 return desc->colorspace == UTIL_FORMAT_COLORSPACE_RGB; 172 } 173
Indexes created Sat Aug 01 00:24:56 UTC 2026