hosted/cmsis_dap: Added a quirk restricting when the ZLP read for Bul…

…k adaptors is done so we don't clobber performance on adaptors that don't need it

src/platforms/hosted/cmsis_dap.c

@@ -351,6 +351,10 @@ bool dap_init(bool allow_fallback)
 		dap_version_compare_le(adaptor_version, (dap_version_s){1, 3, 1}))
 		dap_quirks |= DAP_QUIRK_BAD_SWD_NO_RESP_DATA_PHASE;
 
+	/* ORBTrace needs an extra ZLP read done on full packet reception */
+	if (strcmp(bmda_probe_info.product, "Orbtrace") == 0)
+		dap_quirks |= DAP_QUIRK_NEEDS_EXTRA_ZLP_READ;
+
 	return true;
 }
 
@@ -513,8 +517,9 @@ ssize_t dbg_dap_cmd_bulk(const uint8_t *const request_data, const size_t request
 			return response_result;
 		}
 	} while (response_data[0] != request_data[0]);
+
 	/* If the response requested is the size of the packet size for the adaptor, generate a ZLP read to clean state */
-	if (transferred == (int)dap_packet_size) {
+	if ((dap_quirks & DAP_QUIRK_NEEDS_EXTRA_ZLP_READ) && transferred == (int)dap_packet_size) {
 		uint8_t zlp;
 		int zlp_read = 0;
 		libusb_bulk_transfer(usb_handle, in_ep, &zlp, sizeof(zlp), &zlp_read, TRANSFER_TIMEOUT_MS);

src/platforms/hosted/dap.h

@@ -72,6 +72,7 @@ typedef enum dap_led_type {
 #define DAP_QUIRK_NO_JTAG_MUTLI_TAP          (1U << 0U)
 #define DAP_QUIRK_BAD_SWD_NO_RESP_DATA_PHASE (1U << 1U)
 #define DAP_QUIRK_BROKEN_SWD_SEQUENCE        (1U << 2U)
+#define DAP_QUIRK_NEEDS_EXTRA_ZLP_READ       (1U << 3U)
 
 extern uint8_t dap_caps;
 extern dap_cap_e dap_mode;