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 <address@hidden>
---
Makefile.target | 2 +-
dma-helpers.c | 29 +++++++++++++++++++++++++++++
dma.h | 24 ++++++++++++++++++++++++
3 files changed, 54 insertions(+), 1 deletions(-)
create mode 100644 dma-helpers.c
create mode 100644 dma.h
diff --git a/Makefile.target b/Makefile.target
index 372d185..28ba17f 100644
--- a/Makefile.target
+++ b/Makefile.target
@@ -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
diff --git a/dma-helpers.c b/dma-helpers.c
new file mode 100644
index 0000000..315834e
--- /dev/null
+++ b/dma-helpers.c
@@ -0,0 +1,29 @@
+ 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);
+}
+
diff --git a/dma.h b/dma.h
new file mode 100644
index 0000000..3b56fa6
--- /dev/null
+++ b/dma.h
@@ -0,0 +1,24 @@
+#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