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

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Scatter-gather lists are used extensively in dma-capable devices; a
single data structure allows more code reuse later on.

Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>


git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@6522 c046a42c-6fe2-441c-8c8c-71466251a162
This commit is contained in:
aliguori 2009-02-05 21:23:50 +00:00
parent f39023833e
commit 244ab90e17
3 changed files with 72 additions and 1 deletions
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2
Makefile.target
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@ -500,7 +500,7 @@ endif #CONFIG_BSD_USER
# System emulator target
ifndef CONFIG_USER_ONLY
OBJS=vl.o osdep.o monitor.o pci.o loader.o isa_mmio.o machine.o
OBJS=vl.o osdep.o monitor.o pci.o loader.o isa_mmio.o machine.o dma-helpers.o
# virtio has to be here due to weird dependency between PCI and virtio-net.
# need to fix this properly
OBJS+=virtio.o virtio-blk.o virtio-balloon.o virtio-net.o virtio-console.o

38
dma-helpers.c Normal file
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@ -0,0 +1,38 @@
/*
* 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);
}

33
dma.h Normal file
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@ -0,0 +1,33 @@
/*
* 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.
*/
#ifndef DMA_H
#define DMA_H
#include <stdio.h>
#include "cpu.h"
typedef struct {
target_phys_addr_t base;
target_phys_addr_t len;
} ScatterGatherEntry;
typedef struct {
ScatterGatherEntry *sg;
int nsg;
int nalloc;
target_phys_addr_t size;
} QEMUSGList;
void qemu_sglist_init(QEMUSGList *qsg, int alloc_hint);
void qemu_sglist_add(QEMUSGList *qsg, target_phys_addr_t base,
target_phys_addr_t len);
void qemu_sglist_destroy(QEMUSGList *qsg);
#endif