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-rw-r--r--common/bouncebuf.c92
1 files changed, 92 insertions, 0 deletions
diff --git a/common/bouncebuf.c b/common/bouncebuf.c
new file mode 100644
index 0000000..4f827f8
--- /dev/null
+++ b/common/bouncebuf.c
@@ -0,0 +1,92 @@
+/*
+ * Generic bounce buffer implementation
+ *
+ * Copyright (C) 2012 Marek Vasut <marex@denx.de>
+ *
+ * See file CREDITS for list of people who contributed to this
+ * project.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of
+ * the License, or (at your option) any later version.
+ *
+ * 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., 59 Temple Place, Suite 330, Boston,
+ * MA 02111-1307 USA
+ */
+
+#include <common.h>
+#include <malloc.h>
+#include <errno.h>
+#include <bouncebuf.h>
+
+static int addr_aligned(void *data, size_t len)
+{
+ const ulong align_mask = ARCH_DMA_MINALIGN - 1;
+
+ /* Check if start is aligned */
+ if ((ulong)data & align_mask) {
+ debug("Unaligned start address %p\n", data);
+ return 0;
+ }
+
+ data += len;
+
+ /* Check if end is aligned */
+ if ((ulong)data & align_mask) {
+ debug("Unaligned end address %p\n", data);
+ return 0;
+ }
+
+ /* Aligned */
+ return 1;
+}
+
+int bounce_buffer_start(void **data, size_t len, void **backup, uint8_t flags)
+{
+ void *tmp;
+ size_t alen;
+
+ if (addr_aligned(*data, len)) {
+ *backup = NULL;
+ return 0;
+ }
+
+ alen = roundup(len, ARCH_DMA_MINALIGN);
+ tmp = memalign(ARCH_DMA_MINALIGN, alen);
+
+ if (!tmp)
+ return -ENOMEM;
+
+ if (flags & GEN_BB_READ)
+ memcpy(tmp, *data, len);
+
+ *backup = *data;
+ *data = tmp;
+
+ return 0;
+}
+
+int bounce_buffer_stop(void **data, size_t len, void **backup, uint8_t flags)
+{
+ void *tmp = *data;
+
+ /* The buffer was already aligned, since "backup" is NULL. */
+ if (!*backup)
+ return 0;
+
+ if (flags & GEN_BB_WRITE)
+ memcpy(*backup, *data, len);
+
+ *data = *backup;
+ free(tmp);
+
+ return 0;
+}