linux/drivers/gpu/drm/omapdrm/tcm-sita.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * SImple Tiler Allocator (SiTA): 2D and 1D allocation(reservation) algorithm
 *
 * Authors: Ravi Ramachandra <[email protected]>,
 *          Lajos Molnar <[email protected]>
 *          Andy Gross <[email protected]>
 *
 * Copyright (C) 2012 Texas Instruments Incorporated - https://www.ti.com/
 */
#include <linux/init.h>
#include <linux/module.h>
#include <linux/errno.h>
#include <linux/sched.h>
#include <linux/wait.h>
#include <linux/bitmap.h>
#include <linux/slab.h>
#include "tcm.h"

static unsigned long mask[8];
/*
 * pos		position in bitmap
 * w		width in slots
 * h		height in slots
 * map		ptr to bitmap
 * stride		slots in a row
 */
static void free_slots(unsigned long pos, u16 w, u16 h,
		unsigned long *map, u16 stride)
{ … }

/*
 * w		width in slots
 * pos		ptr to position
 * map		ptr to bitmap
 * num_bits	number of bits in bitmap
 */
static int r2l_b2t_1d(u16 w, unsigned long *pos, unsigned long *map,
		size_t num_bits)
{ … }

/*
 * w = width in slots
 * h = height in slots
 * a = align in slots	(mask, 2^n-1, 0 is unaligned)
 * offset = offset in bytes from 4KiB
 * pos = position in bitmap for buffer
 * map = bitmap ptr
 * num_bits = size of bitmap
 * stride = bits in one row of container
 */
static int l2r_t2b(u16 w, u16 h, u16 a, s16 offset,
		unsigned long *pos, unsigned long slot_bytes,
		unsigned long *map, size_t num_bits, size_t slot_stride)
{ … }

static s32 sita_reserve_1d(struct tcm *tcm, u32 num_slots,
			   struct tcm_area *area)
{ … }

static s32 sita_reserve_2d(struct tcm *tcm, u16 h, u16 w, u16 align,
				s16 offset, u16 slot_bytes,
				struct tcm_area *area)
{ … }

static void sita_deinit(struct tcm *tcm)
{ … }

static s32 sita_free(struct tcm *tcm, struct tcm_area *area)
{ … }

struct tcm *sita_init(u16 width, u16 height)
{ … }