drivers/infiniband/hw/mlx5/mem.c

/*
 * Copyright (c) 2013-2015, Mellanox Technologies. All rights reserved.
 *
 * This software is available to you under a choice of one of two
 * licenses.  You may choose to be licensed under the terms of the GNU
 * General Public License (GPL) Version 2, available from the file
 * COPYING in the main directory of this source tree, or the
 * OpenIB.org BSD license below:
 *
 *     Redistribution and use in source and binary forms, with or
 *     without modification, are permitted provided that the following
 *     conditions are met:
 *
 *      - Redistributions of source code must retain the above
 *        copyright notice, this list of conditions and the following
 *        disclaimer.
 *
 *      - Redistributions in binary form must reproduce the above
 *        copyright notice, this list of conditions and the following
 *        disclaimer in the documentation and/or other materials
 *        provided with the distribution.
 *
 * 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.
 */

#include <rdma/ib_umem_odp.h>
#include "mlx5_ib.h"

/*
 * Fill in a physical address list. ib_umem_num_dma_blocks() entries will be
 * filled in the pas array.
 */
void mlx5_ib_populate_pas(struct ib_umem *umem, size_t page_size, __be64 *pas,
			  u64 access_flags)
{
	struct ib_block_iter biter;

	rdma_umem_for_each_dma_block (umem, &biter, page_size) {
		*pas = cpu_to_be64(rdma_block_iter_dma_address(&biter) |
				   access_flags);
		pas++;
	}
}

/*
 * Compute the page shift and page_offset for mailboxes that use a quantized
 * page_offset. The granulatity of the page offset scales according to page
 * size.
 */
unsigned long __mlx5_umem_find_best_quantized_pgoff(
	struct ib_umem *umem, unsigned long pgsz_bitmap,
	unsigned int page_offset_bits, u64 pgoff_bitmask, unsigned int scale,
	unsigned int *page_offset_quantized)
{
	const u64 page_offset_mask = (1UL << page_offset_bits) - 1;
	unsigned long page_size;
	u64 page_offset;

	page_size = ib_umem_find_best_pgoff(umem, pgsz_bitmap, pgoff_bitmask);
	if (!page_size)
		return 0;

	/*
	 * page size is the largest possible page size.
	 *
	 * Reduce the page_size, and thus the page_offset and quanta, until the
	 * page_offset fits into the mailbox field. Once page_size < scale this
	 * loop is guaranteed to terminate.
	 */
	page_offset = ib_umem_dma_offset(umem, page_size);
	while (page_offset & ~(u64)(page_offset_mask * (page_size / scale))) {
		page_size /= 2;
		page_offset = ib_umem_dma_offset(umem, page_size);
	}

	/*
	 * The address is not aligned, or otherwise cannot be represented by the
	 * page_offset.
	 */
	if (!(pgsz_bitmap & page_size))
		return 0;

	*page_offset_quantized =
		(unsigned long)page_offset / (page_size / scale);
	if (WARN_ON(*page_offset_quantized > page_offset_mask))
		return 0;
	return page_size;
}