drivers/scsi/isci/core/sci_base_memory_descriptor_list.c

/*
 * This file is provided under a dual BSD/GPLv2 license.  When using or
 * redistributing this file, you may do so under either license.
 *
 * GPL LICENSE SUMMARY
 *
 * Copyright(c) 2008 - 2011 Intel Corporation. All rights reserved.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of version 2 of the GNU General Public License as
 * published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
 * The full GNU General Public License is included in this distribution
 * in the file called LICENSE.GPL.
 *
 * BSD LICENSE
 *
 * Copyright(c) 2008 - 2011 Intel Corporation. All rights reserved.
 * All rights reserved.
 *
 * 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.
 *   * Neither the name of Intel Corporation nor the names of its
 *     contributors may be used to endorse or promote products derived
 *     from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

/**
 * This file contains the base implementation for the memory descriptor list.
 *    This is currently comprised of MDL iterator methods.
 *
 *
 */

#include "sci_environment.h"
#include "sci_base_memory_descriptor_list.h"

/*
 * ******************************************************************************
 * * P U B L I C   M E T H O D S
 * ****************************************************************************** */

void sci_mdl_first_entry(
	struct sci_base_memory_descriptor_list *base_mdl)
{
	base_mdl->next_index = 0;

	/*
	 * If this MDL is managing another MDL, then recursively rewind that MDL
	 * object as well. */
	if (base_mdl->next_mdl != SCI_INVALID_HANDLE)
		sci_mdl_first_entry(base_mdl->next_mdl);
}


void sci_mdl_next_entry(
	struct sci_base_memory_descriptor_list *base_mdl)
{
	/*
	 * If there is at least one more entry left in the array, then change
	 * the next pointer to it. */
	if (base_mdl->next_index < base_mdl->length)
		base_mdl->next_index++;
	else if (base_mdl->next_index == base_mdl->length) {
		/*
		 * This MDL has exhausted it's set of entries.  If this MDL is managing
		 * another MDL, then start iterating through that MDL. */
		if (base_mdl->next_mdl != SCI_INVALID_HANDLE)
			sci_mdl_next_entry(base_mdl->next_mdl);
	}
}


struct sci_physical_memory_descriptor *sci_mdl_get_current_entry(
	struct sci_base_memory_descriptor_list *base_mdl)
{
	if (base_mdl->next_index < base_mdl->length)
		return &base_mdl->mde_array[base_mdl->next_index];
	else if (base_mdl->next_index == base_mdl->length) {
		/*
		 * This MDL has exhausted it's set of entries.  If this MDL is managing
		 * another MDL, then return it's current entry. */
		if (base_mdl->next_mdl != SCI_INVALID_HANDLE)
			return sci_mdl_get_current_entry(base_mdl->next_mdl);
	}

	return NULL;
}

/*
 * ******************************************************************************
 * * P R O T E C T E D   M E T H O D S
 * ****************************************************************************** */

void sci_base_mdl_construct(
	struct sci_base_memory_descriptor_list *mdl,
	struct sci_physical_memory_descriptor *mde_array,
	u32 mde_array_length,
	struct sci_base_memory_descriptor_list *next_mdl)
{
	mdl->length     = mde_array_length;
	mdl->mde_array  = mde_array;
	mdl->next_index = 0;
	mdl->next_mdl   = next_mdl;
}

/* --------------------------------------------------------------------------- */

bool sci_base_mde_is_valid(
	struct sci_physical_memory_descriptor *mde,
	u32 alignment,
	u32 size,
	u16 attributes)
{
	/* Only need the lower 32 bits to ensure alignment is met. */
	u32 physical_address = lower_32_bits(mde->physical_address);

	if (
		((((unsigned long)mde->virtual_address) & (alignment - 1)) != 0)
		|| ((physical_address & (alignment - 1)) != 0)
		|| (mde->constant_memory_alignment != alignment)
		|| (mde->constant_memory_size != size)
		|| (mde->virtual_address == NULL)
		|| (mde->constant_memory_attributes != attributes)
		) {
		return false;
	}

	return true;
}