adi_v5_jtag: implement DAP WAIT support

ADIv5 specifies that DP and AP accesses may generate a WAIT
response when the hardware is not able to complete a request for various
reasons in time before the next request is sent. Currently, the software
treats a WAIT response as a fatal error and aborts operation on the DAP.

This patch implements WAIT handling by keeping a journal of all
outstanding and completed accesses, including their response status.
At certain times (when dap_run() is called), the journal is inspected
for WAIT responses and all discarded accesses are replayed to complete
them. Special care is taken to not re-execute already successfully
completed operations.

Change-Id: I2790070388cf1ab2e8c9a042d74eb3ef776aa583
Signed-off-by: Matthias Welwarsky <matthias@welwarsky.de>
Reviewed-on: http://openocd.zylin.com/3166
Tested-by: jenkins
Reviewed-by: Paul Fertser <fercerpav@gmail.com>

src/target/arm_adi_v5.h

@@ -31,6 +31,7 @@
  * resources accessed through a MEM-AP.
  */
 
+#include <helper/list.h>
 #include "arm_jtag.h"
 
 /* FIXME remove these JTAG-specific decls when mem_ap_read_buf_u32()
@@ -206,6 +207,9 @@ struct adiv5_ap {
 struct adiv5_dap {
 	const struct dap_ops *ops;
 
+	/* dap transaction list for WAIT support */
+	struct list_head cmd_journal;
+
 	struct jtag_tap *tap;
 	/* Control config */
 	uint32_t dp_ctrl_stat;