main: add option to specify device index

README.md

@@ -167,14 +167,17 @@ openFPGALoader -- a program to flash FPGA
   -b, --board arg           board name, may be used instead of cable
   -c, --cable arg           jtag interface
       --ftdi-serial arg     FTDI chip serial number
-      --ftdi-channel arg  FTDI chip channel number (channels 0-3 map to A-D)
+      --ftdi-channel arg    FTDI chip channel number (channels 0-3 map to
+                            A-D)
   -d, --device arg          device to use (/dev/ttyUSBx)
       --detect              detect FPGA
       --file-type arg       provides file type instead of let's deduced by
                             using extension
+      --fpga-part arg       fpga model flavor + package
       --freq arg            jtag frequency (Hz)
-  -f, --write-flash       write bitstream in flash (default: false, only for
+  -f, --write-flash         write bitstream in flash (default: false, only
-                          Gowin and ECP5 devices)
+                            for Gowin and ECP5 devices)
+      --index-chain arg     device index in JTAG-chain
       --list-boards         list all supported boards
       --list-cables         list all supported cables
       --list-fpga           list all supported FPGA
@@ -182,6 +185,7 @@ openFPGALoader -- a program to flash FPGA
                             Gowin and ECP5 devices)
   -o, --offset arg          start offset in EEPROM
       --pins arg            pin config (only for ft232R) TDI:TDO:TCK:TMS
+      --probe-firmware arg  firmware for JTAG probe (usbBlasterII)
       --quiet               Produce quiet output (no progress bar)
   -r, --reset               reset FPGA after operations
       --spi                 SPI mode (only for FTDI in serial mode)

src/main.cpp

@@ -64,6 +64,7 @@ struct arguments {
 	string file_type;
 	string fpga_part;
 	string probe_firmware;
+	int index_chain;
 };
 
 int parse_opt(int argc, char **argv, struct arguments *args, jtag_pins_conf_t *pins_config);
@@ -79,7 +80,7 @@ int main(int argc, char **argv)
 	/* command line args. */
 	struct arguments args = {0, false, false, 0, "", "", "-", "", -1, 6000000, "-",
 			false, false, false, false, Device::WR_SRAM, false, false, "",
-			"", ""};
+			"", "", 0};
 	/* parse arguments */
 	try {
 		if (parse_opt(argc, argv, &args, &pins_config))
@@ -274,11 +275,13 @@ int main(int argc, char **argv)
 	}
 
 	if (found != 0) {
+		if (args.index_chain == -1) {
 			for (int i = 0; i < found; i++) {
 				if (fpga_list.find(listDev[i]) != fpga_list.end()) {
 					index = i;
 					if (idcode != -1) {
-					printError("Error: currently only one device is supported");
+						printError("Error: more than one FPGA found");
+						printError("Use --index-chain to force selection");
 						for (int i = 0; i < found; i++)
 							printf("0x%08x\n", listDev[i]);
 						delete(jtag);
@@ -288,6 +291,15 @@ int main(int argc, char **argv)
 					}
 				}
 			}
+		} else {
+			index = args.index_chain;
+			if (index > found || index < 0) {
+				printError("wrong index for device in JTAG chain");
+				delete(jtag);
+				return EXIT_FAILURE;
+			}
+			idcode = listDev[index];
+		}
 	} else {
 		printError("Error: no device found");
 		delete(jtag);
@@ -296,6 +308,9 @@ int main(int argc, char **argv)
 
 	jtag->device_select(index);
 
+	/* check if selected device is supported
+	 * mainly used in conjunction with --index-chain
+	 */
 	if (fpga_list.find(idcode) == fpga_list.end()) {
 		cerr << "Error: device " << hex << idcode << " not supported" << endl;
 		delete(jtag);
@@ -413,6 +428,8 @@ int parse_opt(int argc, char **argv, struct arguments *args, jtag_pins_conf_t *p
 			("freq",        "jtag frequency (Hz)", cxxopts::value<string>(freqo))
 			("f,write-flash",
 				"write bitstream in flash (default: false, only for Gowin and ECP5 devices)")
+			("index-chain",  "device index in JTAG-chain",
+				cxxopts::value<int>(args->index_chain))
 			("list-boards", "list all supported boards",
 				cxxopts::value<bool>(args->list_boards))
 			("list-cables", "list all supported cables",