const struct swd_driver *swd = adiv5_dap_swd_driver(dap);
assert(swd);
- swd->write_reg(swd_cmd(false, false, DP_ABORT),
+ swd->write_reg(swd_cmd(false, false, DP_ABORT),
STKCMPCLR | STKERRCLR | WDERRCLR | ORUNERRCLR, 0);
}
static int swd_connect(struct adiv5_dap *dap)
{
const struct swd_driver *swd = adiv5_dap_swd_driver(dap);
- uint32_t dpidr;
+ uint32_t dpidr = 0xdeadbeef;
int status;
/* FIXME validate transport config ... is the
}
}
- /* 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);
+ 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);
- swd_queue_dp_read(dap, DP_DPIDR, &dpidr);
+ status = swd_queue_dp_read(dap, DP_DPIDR, &dpidr);
+ if (status == ERROR_OK) {
+ status = swd_run_inner(dap);
+ if (status == ERROR_OK)
+ break;
+ }
- /* force clear all sticky faults */
- swd_clear_sticky_errors(dap);
+ alive_sleep(1);
- status = swd_run_inner(dap);
+ } while (timeval_ms() < timeout);
- if (status == ERROR_OK) {
- LOG_INFO("SWD DPIDR %#8.8" PRIx32, dpidr);
+ 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);
- } else
- dap->do_reconnect = true;
return status;
}
if (retval != ERROR_OK)
return retval;
- swd->read_reg(swd_cmd(true, true, reg), dap->last_read, ap->memaccess_tck);
+ swd->read_reg(swd_cmd(true, true, reg), dap->last_read, ap->memaccess_tck);
dap->last_read = data;
return check_sync(dap);
if (retval != ERROR_OK)
return retval;
- swd->write_reg(swd_cmd(false, true, reg), data, ap->memaccess_tck);
+ swd->write_reg(swd_cmd(false, true, reg), data, ap->memaccess_tck);
return check_sync(dap);
}