Add a scatter-gather list type and accessors (Avi Kivity)

[qemu.git] / dma-helpers.c

/*
 * DMA helper functions
 *
 * Copyright (c) 2009 Red Hat
 *
 * This work is licensed under the terms of the GNU General Public License
 * (GNU GPL), version 2 or later.
 */

#include "dma.h"


void qemu_sglist_init(QEMUSGList *qsg, int alloc_hint)
{
    qsg->sg = qemu_malloc(alloc_hint * sizeof(ScatterGatherEntry));
    qsg->nsg = 0;
    qsg->nalloc = alloc_hint;
    qsg->size = 0;
}

void qemu_sglist_add(QEMUSGList *qsg, target_phys_addr_t base,
                     target_phys_addr_t len)
{
    if (qsg->nsg == qsg->nalloc) {
        qsg->nalloc = 2 * qsg->nalloc + 1;
        qsg->sg = qemu_realloc(qsg->sg, qsg->nalloc * sizeof(ScatterGatherEntry));
    }
    qsg->sg[qsg->nsg].base = base;
    qsg->sg[qsg->nsg].len = len;
    qsg->size += len;
    ++qsg->nsg;
}

void qemu_sglist_destroy(QEMUSGList *qsg)
{
    qemu_free(qsg->sg);
}