1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
|
/*
* Copyright (C) 2019 Collabora
*
* 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:
* Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com>
*/
#include "pan_resource.h"
#include "util/u_format.h"
/* Arm FrameBuffer Compression (AFBC) is a lossless compression scheme natively
* implemented in Mali GPUs (as well as many display controllers paired with
* Mali GPUs, etc). Where possible, Panfrost prefers to use AFBC for both
* rendering and texturing. In most cases, this is a performance-win due to a
* dramatic reduction in memory bandwidth and cache locality compared to a
* linear resources.
*
* AFBC divides the framebuffer into 16x16 tiles (other sizes possible, TODO:
* do we need to support this?). So, the width and height each must be aligned
* up to 16 pixels. This is inherently good for performance; note that for a 4
* byte-per-pixel format like RGBA8888, that means that rows are 16*4=64 byte
* aligned, which is the cache-line size.
*
* For each AFBC-compressed resource, there is a single contiguous
* (CPU/GPU-shared) buffer. This buffer itself is divided into two parts:
* header and body, placed immediately after each other.
*
* The AFBC header contains 16 bytes of metadata per tile.
*
* The AFBC body is the same size as the original linear resource (padded to
* the nearest tile). Although the body comes immediately after the header, it
* must also be cache-line aligned, so there can sometimes be a bit of padding
* between the header and body.
*
* As an example, a 64x64 RGBA framebuffer contains 64/16 = 4 tiles horizontally and
* 4 tiles vertically. There are 4*4=16 tiles in total, each containing 16
* bytes of metadata, so there is a 16*16=256 byte header. 64x64 is already
* tile aligned, so the body is 64*64 * 4 bytes per pixel = 16384 bytes of
* body.
*
* From userspace, Panfrost needs to be able to calculate these sizes. It
* explicitly does not and can not know the format of the data contained within
* this header and body. The GPU has native support for AFBC encode/decode. For
* an internal FBO or a framebuffer used for scanout with an AFBC-compatible
* winsys/display-controller, the buffer is maintained AFBC throughout flight,
* and the driver never needs to know the internal data. For edge cases where
* the driver really does need to read/write from the AFBC resource, we
* generate a linear staging buffer and use the GPU to blit AFBC<--->linear.
* TODO: Implement me. */
#define AFBC_TILE_WIDTH 16
#define AFBC_TILE_HEIGHT 16
#define AFBC_HEADER_BYTES_PER_TILE 16
#define AFBC_CACHE_ALIGN 64
/* Is it possible to AFBC compress a particular format? Common formats (and
* YUV) are compressible. Some obscure formats are not and fallback on linear,
* at a performance hit. Also, if you need to disable AFBC entirely in the
* driver for debug/profiling, just always return false here. */
bool
panfrost_format_supports_afbc(enum pipe_format format)
{
const struct util_format_description *desc =
util_format_description(format);
if (util_format_is_rgba8_variant(desc))
return true;
if (format == PIPE_FORMAT_Z32_UNORM)
return true;
/* TODO: AFBC of other formats */
return false;
}
/* AFBC is enabled on a per-resource basis (AFBC enabling is theoretically
* indepdent between color buffers and depth/stencil). To enable, we allocate
* the AFBC metadata buffer and mark that it is enabled. We do -not- actually
* edit the fragment job here. This routine should be called ONCE per
* AFBC-compressed buffer, rather than on every frame. */
void
panfrost_enable_afbc(struct panfrost_context *ctx, struct panfrost_resource *rsrc, bool ds)
{
struct pipe_context *gallium = (struct pipe_context *) ctx;
struct panfrost_screen *screen = pan_screen(gallium->screen);
unsigned width = rsrc->base.width0;
unsigned height = rsrc->base.height0;
unsigned bytes_per_pixel = util_format_get_blocksize(rsrc->base.format);
/* Align to tile */
unsigned aligned_width = ALIGN(width, AFBC_TILE_WIDTH);
unsigned aligned_height = ALIGN(height, AFBC_TILE_HEIGHT);
/* Compute size in tiles, rather than pixels */
unsigned tile_count_x = aligned_width / AFBC_TILE_WIDTH;
unsigned tile_count_y = aligned_height / AFBC_TILE_HEIGHT;
unsigned tile_count = tile_count_x * tile_count_y;
unsigned header_bytes = tile_count * AFBC_HEADER_BYTES_PER_TILE;
unsigned header_size = ALIGN(header_bytes, AFBC_CACHE_ALIGN);
/* The stride is a normal stride, but aligned */
unsigned unaligned_stride = aligned_width * bytes_per_pixel;
unsigned stride = ALIGN(unaligned_stride, AFBC_CACHE_ALIGN);
/* Compute the entire buffer size */
unsigned body_size = stride * aligned_height;
unsigned buffer_size = header_size + body_size;
/* Allocate the AFBC slab itself, large enough to hold the above */
screen->driver->allocate_slab(screen, &rsrc->bo->afbc_slab,
ALIGN(buffer_size, 4096) / 4096,
true, 0, 0, 0);
/* Compressed textured reads use a tagged pointer to the metadata */
rsrc->bo->layout = PAN_AFBC;
rsrc->bo->gpu = rsrc->bo->afbc_slab.gpu | (ds ? 0 : 1);
rsrc->bo->cpu = rsrc->bo->afbc_slab.cpu;
rsrc->bo->gem_handle = rsrc->bo->afbc_slab.gem_handle;
rsrc->bo->afbc_metadata_size = header_size;
}
|
