+ const struct swd_driver *swd = adiv5_dap_swd_driver(dap);
+ uint32_t dpidr = 0xdeadbeef;
+ int status;
+
+ /* FIXME validate transport config ... is the
+ * configured DAP present (check IDCODE)?
+ * Is *only* one DAP configured?
+ *
+ * MUST READ DPIDR
+ */
+
+ /* 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)
+ adapter_assert_reset();
+ else
+ LOG_WARNING("\'srst_nogate\' reset_config option is required");
+ }
+ }
+
+
+ int64_t timeout = timeval_ms() + 500;
+
+ do {
+ /* 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);
+
+ status = swd_queue_dp_read_inner(dap, DP_DPIDR, &dpidr);
+ if (status == ERROR_OK) {
+ status = swd_run_inner(dap);
+ if (status == ERROR_OK)
+ break;
+ }
+
+ alive_sleep(1);
+
+ } while (timeval_ms() < timeout);
+
+ if (status != ERROR_OK) {
+ LOG_ERROR("Error connecting DP: cannot read IDR");
+ return status;
+ }
+
+ LOG_INFO("SWD DPIDR %#8.8" PRIx32, dpidr);
+
+ do {
+ dap->do_reconnect = false;
+
+ /* force clear all sticky faults */
+ swd_clear_sticky_errors(dap);
+
+ status = swd_run_inner(dap);
+ if (status != ERROR_WAIT)
+ break;
+
+ alive_sleep(10);
+
+ } while (timeval_ms() < timeout);
+
+ /* IHI 0031E B4.3.2:
+ * "A WAIT response must not be issued to the ...
+ * ... writes to the ABORT register"
+ * swd_clear_sticky_errors() writes to the ABORT register only.
+ *
+ * Unfortunately at least Microchip SAMD51/E53/E54 returns WAIT
+ * in a corner case. Just try if ABORT resolves the problem.
+ */
+ if (status == ERROR_WAIT) {
+ LOG_WARNING("Connecting DP: stalled AP operation, issuing ABORT");
+
+ dap->do_reconnect = false;
+
+ swd->write_reg(swd_cmd(false, false, DP_ABORT),
+ DAPABORT | STKCMPCLR | STKERRCLR | WDERRCLR | ORUNERRCLR, 0);
+ status = swd_run_inner(dap);
+ }
+
+ if (status == ERROR_OK)
+ status = dap_dp_init(dap);
+
+ return status;