Add a bit-level transfer queue

Interface drivers regularly need to keep track of where each part of a long
read buffer should be copied, once that data arrives. Both source and
destination are often at an arbitrary bit offset.

This queued bit-level copy can help with that, by allowing the driver to
perform postponed reads from the receive buffer already when building the
transmit buffer, and have those reads executed at a later time when data is
available.

For simplicity, it uses the linked list implementation list.h imported from
the Linux kernel.

Change-Id: I06862a0a6f057cbbcacfb021f17a795195faded2
Signed-off-by: Andreas Fritiofson <andreas.fritiofson@gmail.com>
Reviewed-on: http://openocd.zylin.com/450
Tested-by: jenkins
Reviewed-by: Xiaofan <xiaofanc@gmail.com>
Reviewed-by: Freddie Chopin <freddie.chopin@gmail.com>
Reviewed-by: Peter Stuge <peter@stuge.se>

1 files changed, 28 insertions, 1 deletions

diff --git a/src/helper/binarybuffer.h b/src/helper/binarybuffer.h
index 6b142dd..cc0be57 100644
--- a/src/helper/binarybuffer.h
+++ b/src/helper/binarybuffer.h
@@ -24,6 +24,8 @@
 #ifndef BINARYBUFFER_H
 #define BINARYBUFFER_H
 
+#include "list.h"
+
 /** @file
  * Support functions to access arbitrary bits in a byte array
  */
@@ -129,4 +131,29 @@ static inline uint32_t fast_target_buffer_get_u32(const void *p, bool le)
 	return le ? le_to_h_u32(p) : be_to_h_u32(p);
 }
 
-#endif	/* BINARYBUFFER_H */
+static inline void bit_copy(uint8_t *dst, unsigned dst_offset, const uint8_t *src,
+	unsigned src_offset, unsigned bit_count)
+{
+	buf_set_buf(src, src_offset, dst, dst_offset, bit_count);
+}
+
+struct bit_copy_queue {
+	struct list_head list;
+};
+
+struct bit_copy_queue_entry {
+	uint8_t *dst;
+	unsigned dst_offset;
+	const uint8_t *src;
+	unsigned src_offset;
+	unsigned bit_count;
+	struct list_head list;
+};
+
+void bit_copy_queue_init(struct bit_copy_queue *q);
+int bit_copy_queued(struct bit_copy_queue *q, uint8_t *dst, unsigned dst_offset, const uint8_t *src,
+		    unsigned src_offset, unsigned bit_count);
+void bit_copy_execute(struct bit_copy_queue *q);
+void bit_copy_discard(struct bit_copy_queue *q);
+
+#endif /* BINARYBUFFER_H */