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authoraliguori <aliguori@c046a42c-6fe2-441c-8c8c-71466251a162>2009-02-05 21:23:50 +0000
committeraliguori <aliguori@c046a42c-6fe2-441c-8c8c-71466251a162>2009-02-05 21:23:50 +0000
commit244ab90e17e4feefbf35224d6d7bd96d394b4b26 (patch)
treece2ec488052e2515f6b2e8b2ec5950d7e9bafd8f /dma-helpers.c
parentf39023833e4520f411f074a891708591c9ce1e68 (diff)
Add a scatter-gather list type and accessors (Avi Kivity)
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
Diffstat (limited to 'dma-helpers.c')
-rw-r--r--dma-helpers.c38
1 files changed, 38 insertions, 0 deletions
diff --git a/dma-helpers.c b/dma-helpers.c
new file mode 100644
index 0000000000..11ad3a4344
--- /dev/null
+++ b/dma-helpers.c
@@ -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);
+}
+