* 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.
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
***************************************************************************/
/**
* @file
- * This file implements SWD transport support for cores implementing
- the ARM Debug Interface version 5 (ADIv5).
+ * Utilities to support ARM "Serial Wire Debug" (SWD), a low pin-count debug
+ * link protocol used in cases where JTAG is not wanted. This is coupled to
+ * recent versions of ARM's "CoreSight" debug framework. This specific code
+ * is a transport level interface, with "target/arm_adi_v5.[hc]" code
+ * understanding operation semantics, shared with the JTAG transport.
+ *
+ * Single-DAP support only.
+ *
+ * for details, see "ARM IHI 0031A"
+ * ARM Debug Interface v5 Architecture Specification
+ * especially section 5.3 for SWD protocol
+ *
+ * On many chips (most current Cortex-M3 parts) SWD is a run-time alternative
+ * to JTAG. Boards may support one or both. There are also SWD-only chips,
+ * (using SW-DP not SWJ-DP).
+ *
+ * Even boards that also support JTAG can benefit from SWD support, because
+ * usually there's no way to access the SWO trace view mechanism in JTAG mode.
+ * That is, trace access may require SWD support.
+ *
*/
#ifdef HAVE_CONFIG_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,
-};
+#include <transport/transport.h>
+#include <jtag/interface.h>
-/**
- * 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)
+#include <jtag/swd.h>
+
+static bool do_sync;
+
+static void swd_finish_read(struct adiv5_dap *dap)
+{
+ const struct swd_driver *swd = adiv5_dap_swd_driver(dap);
+ if (dap->last_read != NULL) {
+ swd->read_reg(swd_cmd(true, false, DP_RDBUFF), dap->last_read, 0);
+ dap->last_read = NULL;
+ }
+}
+
+static int swd_queue_dp_write(struct adiv5_dap *dap, unsigned reg,
+ uint32_t data);
+static int swd_queue_dp_read(struct adiv5_dap *dap, unsigned reg,
+ uint32_t *data);
+
+static void swd_clear_sticky_errors(struct adiv5_dap *dap)
{
+ const struct swd_driver *swd = adiv5_dap_swd_driver(dap);
+ assert(swd);
+
+ swd->write_reg(swd_cmd(false, false, DP_ABORT),
+ STKCMPCLR | STKERRCLR | WDERRCLR | ORUNERRCLR, 0);
+}
+
+static int swd_run_inner(struct adiv5_dap *dap)
+{
+ const struct swd_driver *swd = adiv5_dap_swd_driver(dap);
int retval;
- LOG_DEBUG("Enter SWD mode");
+ retval = swd->run();
+
+ if (retval != ERROR_OK) {
+ /* fault response */
+ dap->do_reconnect = true;
+ }
+
+ return retval;
+}
- /* REVISIT it's nasty to need to make calls to a "jtag"
- * subsystem if the link isn't in JTAG mode...
+static int swd_connect(struct adiv5_dap *dap)
+{
+ const struct swd_driver *swd = adiv5_dap_swd_driver(dap);
+ uint32_t dpidr;
+ int status;
+
+ /* FIXME validate transport config ... is the
+ * configured DAP present (check IDCODE)?
+ * Is *only* one DAP configured?
+ *
+ * MUST READ DPIDR
*/
- retval = jtag_add_tms_seq(8 * sizeof(jtag2swd_bitseq),
- jtag2swd_bitseq, TAP_INVALID);
- if (retval == ERROR_OK)
- retval = jtag_execute_queue();
+ /* Check if we should reset srst already when connecting, but not if reconnecting. */
+ if (!dap->do_reconnect) {
+ enum reset_types jtag_reset_config = jtag_get_reset_config();
+
+ if (jtag_reset_config & RESET_CNCT_UNDER_SRST) {
+ if (jtag_reset_config & RESET_SRST_NO_GATING)
+ swd_add_reset(1);
+ else
+ LOG_WARNING("\'srst_nogate\' reset_config option is required");
+ }
+ }
+
+ /* Note, debugport_init() does setup too */
+ swd->switch_seq(JTAG_TO_SWD);
+
+ /* Clear link state, including the SELECT cache. */
+ dap->do_reconnect = false;
+ dap_invalidate_cache(dap);
+
+ swd_queue_dp_read(dap, DP_DPIDR, &dpidr);
+
+ /* force clear all sticky faults */
+ swd_clear_sticky_errors(dap);
+
+ status = swd_run_inner(dap);
+
+ if (status == ERROR_OK) {
+ LOG_INFO("SWD DPIDR %#8.8" PRIx32, dpidr);
+ dap->do_reconnect = false;
+ status = dap_dp_init(dap);
+ } else
+ dap->do_reconnect = true;
+
+ return status;
+}
+
+static inline int check_sync(struct adiv5_dap *dap)
+{
+ return do_sync ? swd_run_inner(dap) : ERROR_OK;
+}
+
+static int swd_check_reconnect(struct adiv5_dap *dap)
+{
+ if (dap->do_reconnect)
+ return swd_connect(dap);
+
+ return ERROR_OK;
+}
+
+static int swd_queue_ap_abort(struct adiv5_dap *dap, uint8_t *ack)
+{
+ const struct swd_driver *swd = adiv5_dap_swd_driver(dap);
+ assert(swd);
+
+ swd->write_reg(swd_cmd(false, false, DP_ABORT),
+ DAPABORT | STKCMPCLR | STKERRCLR | WDERRCLR | ORUNERRCLR, 0);
+ return check_sync(dap);
+}
+
+/** Select the DP register bank matching bits 7:4 of reg. */
+static void swd_queue_dp_bankselect(struct adiv5_dap *dap, unsigned reg)
+{
+ /* Only register address 4 is banked. */
+ if ((reg & 0xf) != 4)
+ return;
+
+ uint32_t select_dp_bank = (reg & 0x000000F0) >> 4;
+ uint32_t sel = select_dp_bank
+ | (dap->select & (DP_SELECT_APSEL | DP_SELECT_APBANK));
+
+ if (sel == dap->select)
+ return;
+
+ dap->select = sel;
+
+ swd_queue_dp_write(dap, DP_SELECT, sel);
+}
+
+static int swd_queue_dp_read(struct adiv5_dap *dap, unsigned reg,
+ uint32_t *data)
+{
+ const struct swd_driver *swd = adiv5_dap_swd_driver(dap);
+ assert(swd);
+
+ int retval = swd_check_reconnect(dap);
+ if (retval != ERROR_OK)
+ return retval;
+
+ swd_queue_dp_bankselect(dap, reg);
+ swd->read_reg(swd_cmd(true, false, reg), data, 0);
+
+ return check_sync(dap);
+}
+
+static int swd_queue_dp_write(struct adiv5_dap *dap, unsigned reg,
+ uint32_t data)
+{
+ const struct swd_driver *swd = adiv5_dap_swd_driver(dap);
+ assert(swd);
+
+ int retval = swd_check_reconnect(dap);
+ if (retval != ERROR_OK)
+ return retval;
+
+ swd_finish_read(dap);
+ if (reg == DP_SELECT)
+ dap->select = data & (DP_SELECT_APSEL | DP_SELECT_APBANK | DP_SELECT_DPBANK);
+ else
+ swd_queue_dp_bankselect(dap, reg);
+ swd->write_reg(swd_cmd(false, false, reg), data, 0);
+
+ return check_sync(dap);
+}
+
+/** Select the AP register bank matching bits 7:4 of reg. */
+static void swd_queue_ap_bankselect(struct adiv5_ap *ap, unsigned reg)
+{
+ struct adiv5_dap *dap = ap->dap;
+ uint32_t sel = ((uint32_t)ap->ap_num << 24)
+ | (reg & 0x000000F0)
+ | (dap->select & DP_SELECT_DPBANK);
+
+ if (sel == dap->select)
+ return;
- /* REVISIT set up the DAP's ops vector for SWD mode. */
+ dap->select = sel;
+
+ swd_queue_dp_write(dap, DP_SELECT, sel);
+}
+
+static int swd_queue_ap_read(struct adiv5_ap *ap, unsigned reg,
+ uint32_t *data)
+{
+ struct adiv5_dap *dap = ap->dap;
+ const struct swd_driver *swd = adiv5_dap_swd_driver(dap);
+ assert(swd);
+
+ int retval = swd_check_reconnect(dap);
+ if (retval != ERROR_OK)
+ return retval;
+
+ swd_queue_ap_bankselect(ap, reg);
+ swd->read_reg(swd_cmd(true, true, reg), dap->last_read, ap->memaccess_tck);
+ dap->last_read = data;
+
+ return check_sync(dap);
+}
+
+static int swd_queue_ap_write(struct adiv5_ap *ap, unsigned reg,
+ uint32_t data)
+{
+ struct adiv5_dap *dap = ap->dap;
+ const struct swd_driver *swd = adiv5_dap_swd_driver(dap);
+ assert(swd);
+
+ int retval = swd_check_reconnect(dap);
+ if (retval != ERROR_OK)
+ return retval;
+
+ swd_finish_read(dap);
+ swd_queue_ap_bankselect(ap, reg);
+ swd->write_reg(swd_cmd(false, true, reg), data, ap->memaccess_tck);
+
+ return check_sync(dap);
+}
+
+/** Executes all queued DAP operations. */
+static int swd_run(struct adiv5_dap *dap)
+{
+ swd_finish_read(dap);
+ return swd_run_inner(dap);
+}
+
+/** Put the SWJ-DP back to JTAG mode */
+static void swd_quit(struct adiv5_dap *dap)
+{
+ const struct swd_driver *swd = adiv5_dap_swd_driver(dap);
+
+ swd->switch_seq(SWD_TO_JTAG);
+ /* flush the queue before exit */
+ swd->run();
+}
+
+const struct dap_ops swd_dap_ops = {
+ .connect = swd_connect,
+ .queue_dp_read = swd_queue_dp_read,
+ .queue_dp_write = swd_queue_dp_write,
+ .queue_ap_read = swd_queue_ap_read,
+ .queue_ap_write = swd_queue_ap_write,
+ .queue_ap_abort = swd_queue_ap_abort,
+ .run = swd_run,
+ .quit = swd_quit,
+};
+
+static const struct command_registration swd_commands[] = {
+ {
+ /*
+ * Set up SWD and JTAG targets identically, unless/until
+ * infrastructure improves ... meanwhile, ignore all
+ * JTAG-specific stuff like IR length for SWD.
+ *
+ * REVISIT can we verify "just one SWD DAP" here/early?
+ */
+ .name = "newdap",
+ .jim_handler = jim_jtag_newtap,
+ .mode = COMMAND_CONFIG,
+ .help = "declare a new SWD DAP"
+ },
+ COMMAND_REGISTRATION_DONE
+};
+
+static const struct command_registration swd_handlers[] = {
+ {
+ .name = "swd",
+ .mode = COMMAND_ANY,
+ .help = "SWD command group",
+ .chain = swd_commands,
+ },
+ COMMAND_REGISTRATION_DONE
+};
+
+static int swd_select(struct command_context *ctx)
+{
+ /* FIXME: only place where global 'jtag_interface' is still needed */
+ extern struct jtag_interface *jtag_interface;
+ const struct swd_driver *swd = jtag_interface->swd;
+ int retval;
+
+ retval = register_commands(ctx, NULL, swd_handlers);
+ if (retval != ERROR_OK)
+ return retval;
+
+ /* be sure driver is in SWD mode; start
+ * with hardware default TRN (1), it can be changed later
+ */
+ if (!swd || !swd->read_reg || !swd->write_reg || !swd->init) {
+ LOG_DEBUG("no SWD driver?");
+ return ERROR_FAIL;
+ }
+
+ retval = swd->init();
+ if (retval != ERROR_OK) {
+ LOG_DEBUG("can't init SWD driver");
+ return retval;
+ }
return retval;
}
+static int swd_init(struct command_context *ctx)
+{
+ /* nothing done here, SWD is initialized
+ * together with the DAP */
+ return ERROR_OK;
+}
+
+static struct transport swd_transport = {
+ .name = "swd",
+ .select = swd_select,
+ .init = swd_init,
+};
+
+static void swd_constructor(void) __attribute__((constructor));
+static void swd_constructor(void)
+{
+ transport_register(&swd_transport);
+}
+
+/** Returns true if the current debug session
+ * is using SWD as its transport.
+ */
+bool transport_is_swd(void)
+{
+ return get_current_transport() == &swd_transport;
+}
Code Review / openocd.git / blobdiff