From: Martin Mares <mj@ucw.cz>
Date: Mon, 13 Feb 2012 16:03:38 +0000 (+0100)
Subject: Replace hard-wired endpoint IDs by proper descriptor parsing
X-Git-Tag: v1.3~1
X-Git-Url: http://mj.ucw.cz/gitweb/?a=commitdiff_plain;h=4bad19fd8e55750f4e8ff1605bcef210b2394fa7;p=arexx.git

Replace hard-wired endpoint IDs by proper descriptor parsing
---

diff --git a/arexxd.c b/arexxd.c
index ffd1b4c..8cbd567 100644
--- a/arexxd.c
+++ b/arexxd.c
@@ -300,6 +300,56 @@ static void raw_point(int t, int id, int raw, int q)
 
 /*** USB interface ***/
 
+static int rx_endpoint, tx_endpoint;
+
+static int parse_descriptors(libusb_device *dev)
+{
+	int err;
+	struct libusb_config_descriptor *desc;
+
+	if (err = libusb_get_active_config_descriptor(dev, &desc)) {
+		log_error("libusb_get_config_descriptor failed: error %d", err);
+		return 0;
+	}
+	if (desc->bNumInterfaces != 1) {
+		log_error("Unexpected number of interfaces: %d", desc->bNumInterfaces);
+		goto failed;
+	}
+
+	const struct libusb_interface *iface = &desc->interface[0];
+	if (iface->num_altsetting != 1) {
+		log_error("Unexpected number of alternate interface settings: %d", iface->num_altsetting);
+		goto failed;
+	}
+
+	const struct libusb_interface_descriptor *ifd = &iface->altsetting[0];
+	if (ifd->bNumEndpoints != 2) {
+		log_error("Unexpected number of endpoints: %d", ifd->bNumEndpoints);
+		goto failed;
+	}
+
+	rx_endpoint = tx_endpoint = -1;
+	for (int i=0; i<2; i++) {
+		const struct libusb_endpoint_descriptor *epd = &ifd->endpoint[i];
+		if (epd->bEndpointAddress & 0x80)
+			rx_endpoint = epd->bEndpointAddress;
+		else
+			tx_endpoint = epd->bEndpointAddress;
+	}
+	if (rx_endpoint < 0 || tx_endpoint < 0) {
+		log_error("Failed to identify endpoints");
+		goto failed;
+	}
+
+	log_pkt("Found endpoints: rx==%02x tx=%02x\n", rx_endpoint, tx_endpoint);
+	libusb_free_config_descriptor(desc);
+	return 1;
+
+failed:
+	libusb_free_config_descriptor(desc);
+	return 0;
+}
+
 static int find_device(void)
 {
 	libusb_device **devlist;
@@ -315,6 +365,8 @@ static int find_device(void)
 		if (!libusb_get_device_descriptor(dev, &desc)) {
 			if (desc.idVendor == 0x0451 && desc.idProduct == 0x3211) {
 				log_info("Arexx data logger found at usb%d.%d", libusb_get_bus_number(dev), libusb_get_device_address(dev));
+				if (!parse_descriptors(dev))
+					continue;
 				int err;
 				if (err = libusb_open(dev, &devh)) {
 					log_error("libusb_open() failed: error %d", err);
@@ -368,7 +420,7 @@ static int send_and_receive(byte *req, byte *reply)
 	}
 
 	int err, transferred;
-	if (err = libusb_bulk_transfer(devh, 0x01, req, 64, &transferred, 200)) {
+	if (err = libusb_bulk_transfer(devh, tx_endpoint, req, 64, &transferred, 200)) {
 		if (err == LIBUSB_ERROR_TIMEOUT) {
 			log_pkt(">> xmit timed out\n");
 			return 0;
@@ -381,7 +433,7 @@ static int send_and_receive(byte *req, byte *reply)
 		log_pkt(">> xmit %d bytes\n", transferred);
 		dump_packet(req);
 	}
-	if (err = libusb_bulk_transfer(devh, 0x81, reply, 64, &transferred, 200)) {
+	if (err = libusb_bulk_transfer(devh, rx_endpoint, reply, 64, &transferred, 200)) {
 		if (err == LIBUSB_ERROR_TIMEOUT) {
 			log_pkt("<< recv timed out\n");
 			return 0;