From: Alyssa Rosenzweig Date: Thu, 13 Jun 2019 22:11:21 +0000 (-0700) Subject: panfrost: Calculate polygon list header size X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=edfba9bee24ab1e2632f9b1f92d050ece178b047;p=mesa.git panfrost: Calculate polygon list header size As per the notes at the beginning of pan_tiler.c, we implement a routine to calculate the size of the polygon list header given the framebuffer dimensions and the provided hierarchy mask. Signed-off-by: Alyssa Rosenzweig --- diff --git a/src/gallium/drivers/panfrost/meson.build b/src/gallium/drivers/panfrost/meson.build index 006449fc48f..39f1fd8e6b0 100644 --- a/src/gallium/drivers/panfrost/meson.build +++ b/src/gallium/drivers/panfrost/meson.build @@ -59,7 +59,8 @@ files_panfrost = files( 'pan_pretty_print.c', 'pan_fragment.c', 'pan_sfbd.c', - 'pan_mfbd.c' + 'pan_mfbd.c', + 'pan_tiler.c', ) inc_panfrost = [ diff --git a/src/gallium/drivers/panfrost/pan_tiler.c b/src/gallium/drivers/panfrost/pan_tiler.c index 7e465ed542c..22482ff1f91 100644 --- a/src/gallium/drivers/panfrost/pan_tiler.c +++ b/src/gallium/drivers/panfrost/pan_tiler.c @@ -24,6 +24,10 @@ * Alyssa Rosenzweig */ +#include "util/u_math.h" +#include "util/macros.h" +#include "pan_tiler.h" + /* Mali GPUs are tiled-mode renderers, rather than immediate-mode. * Conceptually, the screen is divided into 16x16 tiles. Vertex shaders run. * Then, a fixed-function hardware block (the tiler) consumes the gl_Position @@ -149,3 +153,104 @@ * size of the statically-sized polygon list structures, allocate them, and go! * */ + +/* Hierarchical tiling spans from 16x16 to 2048x2048 tiles */ + +#define MIN_TILE_SIZE 16 +#define MAX_TILE_SIZE 2048 + +/* Constants as shifts for easier power-of-two iteration */ + +#define MIN_TILE_SHIFT util_logbase2(MIN_TILE_SIZE) +#define MAX_TILE_SHIFT util_logbase2(MAX_TILE_SIZE) + +/* The hierarchy has a 64-byte prologue */ +#define PROLOGUE_SIZE 0x40 + +/* For each tile (across all hierarchy levels), there is 8 bytes of header */ +#define HEADER_BYTES_PER_TILE 0x8 + +/* Absent any geometry, the minimum size of the header */ +#define MINIMUM_HEADER_SIZE 0x200 + +/* If the width-x-height framebuffer is divided into tile_size-x-tile_size + * tiles, how many tiles are there? Rounding up in each direction. For the + * special case of tile_size=16, this aligns with the usual Midgard count. + * tile_size must be a power-of-two. Not really repeat code from AFBC/checksum, + * because those care about the stride (not just the overall count) and only at + * a a fixed-tile size (not any of a number of power-of-twos) */ + +static unsigned +pan_tile_count(unsigned width, unsigned height, unsigned tile_size) +{ + unsigned aligned_width = ALIGN_POT(width, tile_size); + unsigned aligned_height = ALIGN_POT(height, tile_size); + + unsigned tile_count_x = aligned_width / tile_size; + unsigned tile_count_y = aligned_height / tile_size; + + return tile_count_x * tile_count_y; +} + +/* For `masked_count` of the smallest tile sizes masked out, computes how the + * size of the polygon list header. We iterate the tile sizes (16x16 through + * 2048x2048, if nothing is masked; (16*2^masked_count)x(16*2^masked_count) + * through 2048x2048 more generally. For each tile size, we figure out how many + * tiles there are at this hierarchy level and therefore many bytes this level + * is, leaving us with a byte count for each level. We then just sum up the + * byte counts across the levels to find a byte count for all levels. */ + +static unsigned +panfrost_raw_header_size(unsigned width, unsigned height, unsigned masked_count) +{ + unsigned size = PROLOGUE_SIZE; + + /* Normally we start at 16x16 tiles (MIN_TILE_SHIFT), but we add more + * if anything is masked off */ + + unsigned start_level = MIN_TILE_SHIFT + masked_count; + + /* Iterate hierarchy levels / tile sizes */ + + for (unsigned i = start_level; i < MAX_TILE_SHIFT; ++i) { + /* Shift from a level to a tile size */ + unsigned tile_size = (1 << i); + + unsigned tile_count = pan_tile_count(width, height, tile_size); + unsigned header_bytes = HEADER_BYTES_PER_TILE * tile_count; + + size += header_bytes; + } + + /* This size will be used as an offset, so ensure it's aligned */ + return ALIGN_POT(size, 512); +} + +/* Given a hierarchy mask and a framebuffer size, compute the header size */ + +unsigned +panfrost_tiler_header_size(unsigned width, unsigned height, uint8_t mask) +{ + /* If no hierarchy levels are enabled, that means there is no geometry + * for the tiler to process, so use a minimum size. Used for clears */ + + if (mask == 0x00) + return MINIMUM_HEADER_SIZE; + + /* Some levels are enabled. Ensure that only smaller levels are + * disabled and there are no gaps. Theoretically the hardware is more + * flexible, but there's no known reason to use other configurations + * and this keeps the code simple. Since we know the 0x80 bit is set, + * ctz(mask) will return the number of masked off levels. */ + + unsigned masked_count = __builtin_ctz(mask); + + assert(mask & 0x80); + assert(((mask >> masked_count) & ((mask >> masked_count) + 1)) == 0); + + /* Everything looks good. Use the number of trailing zeroes we found to + * figure out how many smaller levels are disabled to compute the + * actual header size */ + + return panfrost_raw_header_size(width, height, masked_count); +}