diff options
author | David Brownell <dbrownell@users.sourceforge.net> | 2010-03-16 14:12:00 -0700 |
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committer | David Brownell <dbrownell@users.sourceforge.net> | 2010-03-16 14:12:00 -0700 |
commit | 6f8b8593d63bc9781435270a54b6f7d245eecd8e (patch) | |
tree | 5b5928e9b4b2cfbafe287dd5d69c85254c099e2d /src/target/adi_v5_swd.c | |
parent | 030ee192dd9647b10ff0841a671facec9d6b833f (diff) |
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>
Diffstat (limited to 'src/target/adi_v5_swd.c')
-rw-r--r-- | src/target/adi_v5_swd.c | 92 |
1 files changed, 92 insertions, 0 deletions
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; +} + |