bitmap.h

/* SPDX-License-Identifier: BSD-3-Clause
 * Copyright(c) 2010-2014 Intel Corporation
 * Copyright(C) 2023 Marvell.
 */

#ifndef __OCT_BITMAP_H__
#define __OCT_BITMAP_H__

#include <stdint.h>
#include <string.h>

#include <util.h>

/* Slab */
#define PLT_BITMAP_SLAB_BIT_SIZE      64
#define PLT_BITMAP_SLAB_BIT_SIZE_LOG2 6
#define PLT_BITMAP_SLAB_BIT_MASK      (PLT_BITMAP_SLAB_BIT_SIZE - 1)

/* Cache line (CL) */
#define PLT_BITMAP_CL_BIT_SIZE	    (PLT_CACHE_LINE_SIZE * 8)
#define PLT_BITMAP_CL_BIT_SIZE_LOG2 (PLT_CACHE_LINE_SIZE_LOG2 + 3)
#define PLT_BITMAP_CL_BIT_MASK	    (PLT_BITMAP_CL_BIT_SIZE - 1)

#define PLT_BITMAP_CL_SLAB_SIZE	     (PLT_BITMAP_CL_BIT_SIZE / PLT_BITMAP_SLAB_BIT_SIZE)
#define PLT_BITMAP_CL_SLAB_SIZE_LOG2 (PLT_BITMAP_CL_BIT_SIZE_LOG2 - PLT_BITMAP_SLAB_BIT_SIZE_LOG2)
#define PLT_BITMAP_CL_SLAB_MASK	     (PLT_BITMAP_CL_SLAB_SIZE - 1)

#define plt_bitmap_scan_init(bmp) __plt_bitmap_scan_init(bmp)

/** Bitmap data structure */
struct plt_bitmap {
	/* Context for array1 and array2 */
	uint64_t *array1;     /**< Bitmap array1 */
	uint64_t *array2;     /**< Bitmap array2 */
	uint32_t array1_size; /**< Number of 64-bit slabs in array1 that are
				 actually used */
	uint32_t array2_size; /**< Number of 64-bit slabs in array2 */

	/* Context for the "scan next" operation */
	uint32_t index1;  /**< Bitmap scan: Index of current array1 slab */
	uint32_t offset1; /**< Bitmap scan: Offset of current bit within current
			     array1 slab */
	uint32_t index2;  /**< Bitmap scan: Index of current array2 slab */
	uint32_t go2;	  /**< Bitmap scan: Go/stop condition for current array2
			     cache line */

	/* Storage space for array1 and array2 */
	uint8_t memory[];
};

static inline void
__plt_bitmap_index1_inc(struct plt_bitmap *bmp)
{
	bmp->index1 = (bmp->index1 + 1) & (bmp->array1_size - 1);
}

static inline uint64_t
__plt_bitmap_mask1_get(struct plt_bitmap *bmp)
{
	return (~1llu) << bmp->offset1;
}

static inline void
__plt_bitmap_index2_set(struct plt_bitmap *bmp)
{
	bmp->index2 = (((bmp->index1 << PLT_BITMAP_SLAB_BIT_SIZE_LOG2) + bmp->offset1)
		       << PLT_BITMAP_CL_SLAB_SIZE_LOG2);
}

static inline uint32_t
__plt_bitmap_get_memory_footprint(uint32_t n_bits, uint32_t *array1_byte_offset,
				  uint32_t *array1_slabs, uint32_t *array2_byte_offset,
				  uint32_t *array2_slabs)
{
	uint32_t n_slabs_context, n_slabs_array1, n_cache_lines_context_and_array1;
	uint32_t n_cache_lines_array2;
	uint32_t n_bytes_total;

	n_cache_lines_array2 = (n_bits + PLT_BITMAP_CL_BIT_SIZE - 1) / PLT_BITMAP_CL_BIT_SIZE;
	n_slabs_array1 =
		(n_cache_lines_array2 + PLT_BITMAP_SLAB_BIT_SIZE - 1) / PLT_BITMAP_SLAB_BIT_SIZE;
	n_slabs_array1 = plt_align32pow2(n_slabs_array1);
	n_slabs_context = (sizeof(struct plt_bitmap) + (PLT_BITMAP_SLAB_BIT_SIZE / 8) - 1) /
			  (PLT_BITMAP_SLAB_BIT_SIZE / 8);
	n_cache_lines_context_and_array1 =
		(n_slabs_context + n_slabs_array1 + PLT_BITMAP_CL_SLAB_SIZE - 1) /
		PLT_BITMAP_CL_SLAB_SIZE;
	n_bytes_total =
		(n_cache_lines_context_and_array1 + n_cache_lines_array2) * PLT_CACHE_LINE_SIZE;

	if (array1_byte_offset)
		*array1_byte_offset = n_slabs_context * (PLT_BITMAP_SLAB_BIT_SIZE / 8);

	if (array1_slabs)
		*array1_slabs = n_slabs_array1;

	if (array2_byte_offset)
		*array2_byte_offset = n_cache_lines_context_and_array1 * PLT_CACHE_LINE_SIZE;

	if (array2_slabs)
		*array2_slabs = n_cache_lines_array2 * PLT_BITMAP_CL_SLAB_SIZE;

	return n_bytes_total;
}

static inline void
__plt_bitmap_scan_init(struct plt_bitmap *bmp)
{
	bmp->index1 = bmp->array1_size - 1;
	bmp->offset1 = PLT_BITMAP_SLAB_BIT_SIZE - 1;
	__plt_bitmap_index2_set(bmp);
	bmp->index2 += PLT_BITMAP_CL_SLAB_SIZE;

	bmp->go2 = 0;
}

/**
 * Bitmap memory footprint calculation
 *
 * @param n_bits
 *   Number of bits in the bitmap
 * @return
 *   Bitmap memory footprint measured in bytes on success, 0 on error
 */
static inline uint32_t
plt_bitmap_get_memory_footprint(uint32_t n_bits)
{
	/* Check input arguments */
	if (n_bits == 0)
		return 0;

	return __plt_bitmap_get_memory_footprint(n_bits, NULL, NULL, NULL, NULL);
}

/**
 * Bitmap initialization
 *
 * @param n_bits
 *   Number of pre-allocated bits in array2.
 * @param mem
 *   Base address of array1 and array2.
 * @param mem_size
 *   Minimum expected size of bitmap.
 * @return
 *   Handle to bitmap instance.
 */
static inline struct plt_bitmap *
plt_bitmap_init(uint32_t n_bits, uint8_t *mem, uint32_t mem_size)
{
	struct plt_bitmap *bmp;
	uint32_t array1_byte_offset, array1_slabs, array2_byte_offset, array2_slabs;
	uint32_t size;

	/* Check input arguments */
	if (n_bits == 0)
		return NULL;

	if ((mem == NULL) || (((uintptr_t)mem) & PLT_CACHE_LINE_MASK))
		return NULL;

	size = __plt_bitmap_get_memory_footprint(n_bits, &array1_byte_offset, &array1_slabs,
						 &array2_byte_offset, &array2_slabs);
	if (size < mem_size)
		return NULL;

	/* Setup bitmap */
	memset(mem, 0, size);
	bmp = (struct plt_bitmap *)mem;

	bmp->array1 = (uint64_t *)&mem[array1_byte_offset];
	bmp->array1_size = array1_slabs;
	bmp->array2 = (uint64_t *)&mem[array2_byte_offset];
	bmp->array2_size = array2_slabs;

	__plt_bitmap_scan_init(bmp);

	return bmp;
}

/**
 * Bitmap free
 *
 * @param bmp
 *   Handle to bitmap instance
 * @return
 *   0 upon success, error code otherwise
 */
static inline int
plt_bitmap_free(struct plt_bitmap *bmp)
{
	/* Check input arguments */
	if (bmp == NULL)
		return -1;

	return 0;
}

/**
 * Bitmap reset
 *
 * @param bmp
 *   Handle to bitmap instance
 */
static inline void
plt_bitmap_reset(struct plt_bitmap *bmp)
{
	memset(bmp->array1, 0, bmp->array1_size * sizeof(uint64_t));
	memset(bmp->array2, 0, bmp->array2_size * sizeof(uint64_t));
	__plt_bitmap_scan_init(bmp);
}

/**
 * Bitmap location prefetch into CPU L1 cache
 *
 * @param bmp
 *   Handle to bitmap instance
 * @param pos
 *   Bit position
 * @return
 *   0 upon success, error code otherwise
 */
static inline void
plt_bitmap_prefetch0(struct plt_bitmap *bmp, uint32_t pos)
{
	uint64_t *slab2;
	uint32_t index2;

	index2 = pos >> PLT_BITMAP_SLAB_BIT_SIZE_LOG2;
	slab2 = bmp->array2 + index2;
	plt_prefetch0(slab2);
}

/**
 * Bitmap bit get
 *
 * @param bmp
 *   Handle to bitmap instance
 * @param pos
 *   Bit position
 * @return
 *   0 when bit is cleared, non-zero when bit is set
 */
static inline uint64_t
plt_bitmap_get(struct plt_bitmap *bmp, uint32_t pos)
{
	uint64_t *slab2;
	uint32_t index2, offset2;

	index2 = pos >> PLT_BITMAP_SLAB_BIT_SIZE_LOG2;
	offset2 = pos & PLT_BITMAP_SLAB_BIT_MASK;
	slab2 = bmp->array2 + index2;
	return ((*slab2) >> offset2) & 0x1;
}

/**
 * Bitmap bit set
 *
 * @param bmp
 *   Handle to bitmap instance
 * @param pos
 *   Bit position
 */
static inline void
plt_bitmap_set(struct plt_bitmap *bmp, uint32_t pos)
{
	uint64_t *slab1, *slab2;
	uint32_t index1, index2, offset1, offset2;

	/* Set bit in array2 slab and set bit in array1 slab */
	index2 = pos >> PLT_BITMAP_SLAB_BIT_SIZE_LOG2;
	offset2 = pos & PLT_BITMAP_SLAB_BIT_MASK;
	index1 = pos >> (PLT_BITMAP_SLAB_BIT_SIZE_LOG2 + PLT_BITMAP_CL_BIT_SIZE_LOG2);
	offset1 = (pos >> PLT_BITMAP_CL_BIT_SIZE_LOG2) & PLT_BITMAP_SLAB_BIT_MASK;
	slab2 = bmp->array2 + index2;
	slab1 = bmp->array1 + index1;

	*slab2 |= 1llu << offset2;
	*slab1 |= 1llu << offset1;
}

/**
 * Bitmap slab set
 *
 * @param bmp
 *   Handle to bitmap instance
 * @param pos
 *   Bit position identifying the array2 slab
 * @param slab
 *   Value to be assigned to the 64-bit slab in array2
 */
static inline void
plt_bitmap_set_slab(struct plt_bitmap *bmp, uint32_t pos, uint64_t slab)
{
	uint64_t *slab1, *slab2;
	uint32_t index1, index2, offset1;

	/* Set bits in array2 slab and set bit in array1 slab */
	index2 = pos >> PLT_BITMAP_SLAB_BIT_SIZE_LOG2;
	index1 = pos >> (PLT_BITMAP_SLAB_BIT_SIZE_LOG2 + PLT_BITMAP_CL_BIT_SIZE_LOG2);
	offset1 = (pos >> PLT_BITMAP_CL_BIT_SIZE_LOG2) & PLT_BITMAP_SLAB_BIT_MASK;
	slab2 = bmp->array2 + index2;
	slab1 = bmp->array1 + index1;

	*slab2 |= slab;
	*slab1 |= 1llu << offset1;
}

static inline uint64_t
__plt_bitmap_line_not_empty(uint64_t *slab2)
{
	uint64_t v1, v2, v3, v4, v5, v6, v7, v8;

	v1 = slab2[0] | slab2[1];
	v2 = slab2[2] | slab2[3];
	v3 = slab2[4] | slab2[5];
	v4 = slab2[6] | slab2[7];

	v1 |= v2;
	v3 |= v4;

	if (PLT_BITMAP_CL_SLAB_SIZE == 16)
	{
	v5 = slab2[8] | slab2[9];
	v6 = slab2[10] | slab2[11];
	v7 = slab2[12] | slab2[13];
	v8 = slab2[14] | slab2[15];

	v5 |= v6;
	v7 |= v8;

	return v1 | v3 | v5 | v7;
	}

	return v1 | v3;
}

/**
 * Bitmap bit clear
 *
 * @param bmp
 *   Handle to bitmap instance
 * @param pos
 *   Bit position
 */
static inline void
plt_bitmap_clear(struct plt_bitmap *bmp, uint32_t pos)
{
	uint64_t *slab1, *slab2;
	uint32_t index1, index2, offset1, offset2;

	/* Clear bit in array2 slab */
	index2 = pos >> PLT_BITMAP_SLAB_BIT_SIZE_LOG2;
	offset2 = pos & PLT_BITMAP_SLAB_BIT_MASK;
	slab2 = bmp->array2 + index2;

	/* Return if array2 slab is not all-zeros */
	*slab2 &= ~(1llu << offset2);
	if (*slab2)
		return;

	/* Check the entire cache line of array2 for all-zeros */
	index2 &= ~PLT_BITMAP_CL_SLAB_MASK;
	slab2 = bmp->array2 + index2;
	if (__plt_bitmap_line_not_empty(slab2))
		return;

	/* The array2 cache line is all-zeros, so clear bit in array1 slab */
	index1 = pos >> (PLT_BITMAP_SLAB_BIT_SIZE_LOG2 + PLT_BITMAP_CL_BIT_SIZE_LOG2);
	offset1 = (pos >> PLT_BITMAP_CL_BIT_SIZE_LOG2) & PLT_BITMAP_SLAB_BIT_MASK;
	slab1 = bmp->array1 + index1;
	*slab1 &= ~(1llu << offset1);
}

static inline int
__plt_bitmap_scan_search(struct plt_bitmap *bmp)
{
	uint64_t value1;
	uint32_t i;

	/* Check current array1 slab */
	value1 = bmp->array1[bmp->index1];
	value1 &= __plt_bitmap_mask1_get(bmp);

	if (plt_bsf64_safe(value1, &bmp->offset1))
		return 1;

	__plt_bitmap_index1_inc(bmp);
	bmp->offset1 = 0;

	/* Look for another array1 slab */
	for (i = 0; i < bmp->array1_size; i++, __plt_bitmap_index1_inc(bmp)) {
		value1 = bmp->array1[bmp->index1];

		if (plt_bsf64_safe(value1, &bmp->offset1))
			return 1;
	}

	return 0;
}

static inline void
__plt_bitmap_scan_read_init(struct plt_bitmap *bmp)
{
	__plt_bitmap_index2_set(bmp);
	bmp->go2 = 1;
	plt_prefetch1((void *)(bmp->array2 + bmp->index2 + 8));
}

static inline int
__plt_bitmap_scan_read(struct plt_bitmap *bmp, uint32_t *pos, uint64_t *slab)
{
	uint64_t *slab2;

	slab2 = bmp->array2 + bmp->index2;
	for (; bmp->go2; bmp->index2++, slab2++, bmp->go2 = bmp->index2 & PLT_BITMAP_CL_SLAB_MASK) {
		if (*slab2) {
			*pos = bmp->index2 << PLT_BITMAP_SLAB_BIT_SIZE_LOG2;
			*slab = *slab2;

			bmp->index2++;
			slab2++;
			bmp->go2 = bmp->index2 & PLT_BITMAP_CL_SLAB_MASK;
			return 1;
		}
	}

	return 0;
}

/**
 * Bitmap scan (with automatic wrap-around)
 *
 * @param bmp
 *   Handle to bitmap instance
 * @param pos
 *   When function call returns 1, pos contains the position of the next set
 *   bit, otherwise not modified
 * @param slab
 *   When function call returns 1, slab contains the value of the entire 64-bit
 *   slab where the bit indicated by pos is located. Slabs are always 64-bit
 *   aligned, so the position of the first bit of the slab (this bit is not
 *   necessarily set) is pos / 64. Once a slab has been returned by the bitmap
 *   scan operation, the internal pointers of the bitmap are updated to point
 *   after this slab, so the same slab will not be returned again if it
 *   contains more than one bit which is set. When function call returns 0,
 *   slab is not modified.
 * @return
 *   0 if there is no bit set in the bitmap, 1 otherwise
 */
static inline int
plt_bitmap_scan(struct plt_bitmap *bmp, uint32_t *pos, uint64_t *slab)
{
	/* Return data from current array2 line if available */
	if (__plt_bitmap_scan_read(bmp, pos, slab))
		return 1;

	/* Look for non-empty array2 line */
	if (__plt_bitmap_scan_search(bmp)) {
		__plt_bitmap_scan_read_init(bmp);
		__plt_bitmap_scan_read(bmp, pos, slab);
		return 1;
	}

	/* Empty bitmap */
	return 0;
}

#endif /* __OCT_BITMAP_H__ */