From 6f8b8593d63bc9781435270a54b6f7d245eecd8e Mon Sep 17 00:00:00 2001
From: David Brownell <dbrownell@users.sourceforge.net>
Date: Tue, 16 Mar 2010 14:12:00 -0700
Subject: ADIv5 transport support moves to separate files

Unclutter arm_adi_v5.c by moving most transport-specific code
to a transport-specific files adi_v5_{jtag,swd}.c ... it's not
a full cleanup, because of some issues which need to be addressed
as part of SWD support (along with implementing the DAP operations
on top of SWD transport):

 - The mess where mem_ap_read_buf_u32() is currently coded to
   know about JTAG scan chains, and thus needs rewriting before
   it will work with SWD;

 - Initialization is still JTAG-specific

Also  move JTAG_{DP,ACK}_* constants from adi_v5.h to the JTAG
file; no other code should care about those values.

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
---
 src/target/adi_v5_swd.c | 92 +++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 92 insertions(+)
 create mode 100644 src/target/adi_v5_swd.c

(limited to 'src/target/adi_v5_swd.c')

diff --git a/src/target/adi_v5_swd.c b/src/target/adi_v5_swd.c
new file mode 100644
index 00000000..f103e4b0
--- /dev/null
+++ b/src/target/adi_v5_swd.c
@@ -0,0 +1,92 @@
+/***************************************************************************
+ *
+ *   Copyright (C) 2010 by David Brownell
+ *
+ *   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.
+ ***************************************************************************/
+
+/**
+ * @file
+ * This file implements SWD transport support for cores implementing
+ the ARM Debug Interface version 5 (ADIv5).
+ */
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include "arm.h"
+#include "arm_adi_v5.h"
+#include <helper/time_support.h>
+
+/*
+ * This represents the bits which must be sent out on TMS/SWDIO to
+ * switch a DAP implemented using an SWJ-DP module into SWD mode.
+ * These bits are stored (and transmitted) LSB-first.
+ *
+ * See the DAP-Lite specification, section 2.2.5 for information
+ * about making the debug link select SWD or JTAG.  (Similar info
+ * is in a few other ARM documents.)
+ */
+static const uint8_t jtag2swd_bitseq[] = {
+	/* More than 50 TCK/SWCLK cycles with TMS/SWDIO high,
+	 * putting both JTAG and SWD logic into reset state.
+	 */
+	0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+	/* Switching sequence enables SWD and disables JTAG
+	 * NOTE: bits in the DP's IDCODE may expose the need for
+	 * an old/deprecated sequence (0xb6 0xed).
+	 */
+	0x9e, 0xe7,
+	/* More than 50 TCK/SWCLK cycles with TMS/SWDIO high,
+	 * putting both JTAG and SWD logic into reset state.
+	 */
+	0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+};
+
+/**
+ * Put the debug link into SWD mode, if the target supports it.
+ * The link's initial mode may be either JTAG (for example,
+ * with SWJ-DP after reset) or SWD.
+ *
+ * @param target Enters SWD mode (if possible).
+ *
+ * Note that targets using the JTAG-DP do not support SWD, and that
+ * some targets which could otherwise support it may have have been
+ * configured to disable SWD signaling
+ *
+ * @return ERROR_OK or else a fault code.
+ */
+int dap_to_swd(struct target *target)
+{
+	int retval;
+
+	LOG_DEBUG("Enter SWD mode");
+
+	/* REVISIT it's nasty to need to make calls to a "jtag"
+	 * subsystem if the link isn't in JTAG mode...
+	 */
+
+	retval =  jtag_add_tms_seq(8 * sizeof(jtag2swd_bitseq),
+			jtag2swd_bitseq, TAP_INVALID);
+	if (retval == ERROR_OK)
+		retval = jtag_execute_queue();
+
+	/* REVISIT set up the DAP's ops vector for SWD mode. */
+
+	return retval;
+}
+
-- 
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