mesa/src/panfrost/lib/pan_afbc.c

190 lines
7.2 KiB
C

/*
* Copyright (C) 2019 Collabora, Ltd.
*
* 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_texture.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.
*/
static enum pipe_format
unswizzled_format(enum pipe_format format)
{
switch (format) {
case PIPE_FORMAT_A8_UNORM:
case PIPE_FORMAT_L8_UNORM:
case PIPE_FORMAT_I8_UNORM:
return PIPE_FORMAT_R8_UNORM;
case PIPE_FORMAT_L8A8_UNORM:
return PIPE_FORMAT_R8G8_UNORM;
case PIPE_FORMAT_B8G8R8_UNORM:
return PIPE_FORMAT_R8G8B8_UNORM;
case PIPE_FORMAT_R8G8B8X8_UNORM:
case PIPE_FORMAT_B8G8R8A8_UNORM:
case PIPE_FORMAT_B8G8R8X8_UNORM:
case PIPE_FORMAT_A8R8G8B8_UNORM:
case PIPE_FORMAT_X8R8G8B8_UNORM:
case PIPE_FORMAT_X8B8G8R8_UNORM:
case PIPE_FORMAT_A8B8G8R8_UNORM:
return PIPE_FORMAT_R8G8B8A8_UNORM;
case PIPE_FORMAT_B5G6R5_UNORM:
return PIPE_FORMAT_R5G6B5_UNORM;
case PIPE_FORMAT_B5G5R5A1_UNORM:
return PIPE_FORMAT_R5G5B5A1_UNORM;
case PIPE_FORMAT_R10G10B10X2_UNORM:
case PIPE_FORMAT_B10G10R10A2_UNORM:
case PIPE_FORMAT_B10G10R10X2_UNORM:
return PIPE_FORMAT_R10G10B10A2_UNORM;
case PIPE_FORMAT_A4B4G4R4_UNORM:
case PIPE_FORMAT_B4G4R4A4_UNORM:
return PIPE_FORMAT_R4G4B4A4_UNORM;
default:
return format;
}
}
/* AFBC supports compressing a few canonical formats. Additional formats are
* available by using a canonical internal format. Given a PIPE format, find
* the canonical AFBC internal format if it exists, or NONE if the format
* cannot be compressed. */
enum pan_afbc_mode
panfrost_afbc_format(unsigned arch, enum pipe_format format)
{
/* sRGB does not change the pixel format itself, only the
* interpretation. The interpretation is handled by conversion hardware
* independent to the compression hardware, so we can compress sRGB
* formats by using the corresponding linear format.
*/
format = util_format_linear(format);
/* Luminance-alpha not supported for AFBC on v7+ */
switch (format) {
case PIPE_FORMAT_A8_UNORM:
case PIPE_FORMAT_L8_UNORM:
case PIPE_FORMAT_I8_UNORM:
case PIPE_FORMAT_L8A8_UNORM:
if (arch >= 7)
return PAN_AFBC_MODE_INVALID;
else
break;
default:
break;
}
/* We handle swizzling orthogonally to AFBC */
format = unswizzled_format(format);
/* clang-format off */
switch (format) {
case PIPE_FORMAT_R8_UNORM: return PAN_AFBC_MODE_R8;
case PIPE_FORMAT_R8G8_UNORM: return PAN_AFBC_MODE_R8G8;
case PIPE_FORMAT_R8G8B8_UNORM: return PAN_AFBC_MODE_R8G8B8;
case PIPE_FORMAT_R8G8B8A8_UNORM: return PAN_AFBC_MODE_R8G8B8A8;
case PIPE_FORMAT_R5G6B5_UNORM: return PAN_AFBC_MODE_R5G6B5;
case PIPE_FORMAT_R5G5B5A1_UNORM: return PAN_AFBC_MODE_R5G5B5A1;
case PIPE_FORMAT_R10G10B10A2_UNORM: return PAN_AFBC_MODE_R10G10B10A2;
case PIPE_FORMAT_R4G4B4A4_UNORM: return PAN_AFBC_MODE_R4G4B4A4;
case PIPE_FORMAT_Z16_UNORM: return PAN_AFBC_MODE_R8G8;
case PIPE_FORMAT_Z24_UNORM_S8_UINT: return PAN_AFBC_MODE_R8G8B8A8;
case PIPE_FORMAT_Z24X8_UNORM: return PAN_AFBC_MODE_R8G8B8A8;
case PIPE_FORMAT_X24S8_UINT: return PAN_AFBC_MODE_R8G8B8A8;
default: return PAN_AFBC_MODE_INVALID;
}
/* clang-format on */
}
/* The lossless colour transform (AFBC_FORMAT_MOD_YTR) requires RGB. */
bool
panfrost_afbc_can_ytr(enum pipe_format format)
{
const struct util_format_description *desc = util_format_description(format);
/* YTR is only defined for RGB(A) */
if (desc->nr_channels != 3 && desc->nr_channels != 4)
return false;
/* The fourth channel if it exists doesn't matter */
return desc->colorspace == UTIL_FORMAT_COLORSPACE_RGB;
}
/* Only support packing for RGB formats for now. */
bool
panfrost_afbc_can_pack(enum pipe_format format)
{
const struct util_format_description *desc = util_format_description(format);
return desc->colorspace == UTIL_FORMAT_COLORSPACE_RGB;
}