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authorMarek Vasut <marex@denx.de>2012-08-26 15:19:06 +0000
committerAndy Fleming <afleming@freescale.com>2012-10-22 02:53:35 -0500
commitb660df3c9031ba2efded2d083c34f2ea5ff978ff (patch)
tree0839439d1b51289dff3b15fc1981246992c220ae /include
parent99070db0dc0b0e881841a0091f06d53351244a34 (diff)
downloadu-boot-linaro-stable-b660df3c9031ba2efded2d083c34f2ea5ff978ff.tar.gz
COMMON: Implement common bounce buffer
Implement common bounce buffer to be used on a less capable hardware. That includes hardware that can not do DMA from any address or such. Signed-off-by: Marek Vasut <marex@denx.de> Cc: Fabio Estevam <festevam@gmail.com> Cc: Andy Fleming <afleming@freescale.com> Signed-off-by: Andy Fleming <afleming@freescale.com>
Diffstat (limited to 'include')
-rw-r--r--include/bouncebuf.h87
1 files changed, 87 insertions, 0 deletions
diff --git a/include/bouncebuf.h b/include/bouncebuf.h
new file mode 100644
index 000000000..31021c5b8
--- /dev/null
+++ b/include/bouncebuf.h
@@ -0,0 +1,87 @@
+/*
+ * 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
+ */
+
+#ifndef __INCLUDE_BOUNCEBUF_H__
+#define __INCLUDE_BOUNCEBUF_H__
+
+/*
+ * GEN_BB_READ -- Data are read from the buffer eg. by DMA hardware.
+ * The source buffer is copied into the bounce buffer (if unaligned, otherwise
+ * the source buffer is used directly) upon start() call, then the operation
+ * requiring the aligned transfer happens, then the bounce buffer is lost upon
+ * stop() call.
+ */
+#define GEN_BB_READ (1 << 0)
+/*
+ * GEN_BB_WRITE -- Data are written into the buffer eg. by DMA hardware.
+ * The source buffer starts in an undefined state upon start() call, then the
+ * operation requiring the aligned transfer happens, then the bounce buffer is
+ * copied into the destination buffer (if unaligned, otherwise destination
+ * buffer is used directly) upon stop() call.
+ */
+#define GEN_BB_WRITE (1 << 1)
+/*
+ * GEN_BB_RW -- Data are read and written into the buffer eg. by DMA hardware.
+ * The source buffer is copied into the bounce buffer (if unaligned, otherwise
+ * the source buffer is used directly) upon start() call, then the operation
+ * requiring the aligned transfer happens, then the bounce buffer is copied
+ * into the destination buffer (if unaligned, otherwise destination buffer is
+ * used directly) upon stop() call.
+ */
+#define GEN_BB_RW (GEN_BB_READ | GEN_BB_WRITE)
+
+#ifdef CONFIG_BOUNCE_BUFFER
+/**
+ * bounce_buffer_start() -- Start the bounce buffer session
+ * data: pointer to buffer to be aligned
+ * len: length of the buffer
+ * backup: pointer to backup buffer (the original value is stored here if
+ * needed
+ * flags: flags describing the transaction, see above.
+ */
+int bounce_buffer_start(void **data, size_t len, void **backup, uint8_t flags);
+/**
+ * bounce_buffer_stop() -- Finish the bounce buffer session
+ * data: pointer to buffer that was aligned
+ * len: length of the buffer
+ * backup: pointer to backup buffer (the original value is stored here if
+ * needed
+ * flags: flags describing the transaction, see above.
+ */
+int bounce_buffer_stop(void **data, size_t len, void **backup, uint8_t flags);
+#else
+static inline int bounce_buffer_start(void **data, size_t len, void **backup,
+ uint8_t flags)
+{
+ return 0;
+}
+
+static inline int bounce_buffer_stop(void **data, size_t len, void **backup,
+ uint8_t flags)
+{
+ return 0;
+}
+#endif
+
+#endif