Test device: fix ZLP handling

java-does-usb/src/test/java/net/codecrete/usb/TestDeviceBase.java

@@ -68,24 +68,11 @@ private static void resetDevice() {
         resetBuffers();
 
         // drain loopback data
-        while (true) {
-            try {
-                testDevice.transferIn(config.endpointLoopbackIn(), 1);
-            } catch (UsbTimeoutException e) {
-                break;
-            }
-        }
+        drainData(config.endpointLoopbackIn());
 
         // drain interrupt data
-        if (isLoopbackDevice()) {
-            while (true) {
-                try {
-                    testDevice.transferIn(config.endpointEchoIn(), 1);
-                } catch (UsbTimeoutException e) {
-                    break;
-                }
-            }
-        }
+        if (isLoopbackDevice())
+            drainData(config.endpointEchoIn());
 
         // reset buffers again
         resetBuffers();
@@ -96,6 +83,16 @@ static void resetBuffers() {
                 (byte) 0x04, (short) 0, (short) config.interfaceNumber()), null);
     }
 
+    static void drainData(int endpointNumber) {
+        while (true) {
+            try {
+                testDevice.transferIn(endpointNumber, 1);
+            } catch (UsbTimeoutException e) {
+                break;
+            }
+        }
+    }
+
     static byte[] generateRandomBytes(int numBytes, long seed) {
         var random = new Random(seed);
         var bytes = new byte[numBytes];

java-does-usb/src/test/java/net/codecrete/usb/TimeoutTest.java

@@ -34,16 +34,14 @@ void bulkTransfer_doesNotTimeOut() {
         var data = generateRandomBytes(20, 7280277392L);
         testDevice.transferOut(config.endpointLoopbackOut(), data);
 
-       var received = testDevice.transferIn(config.endpointLoopbackIn(), 200);
+        var received = testDevice.transferIn(config.endpointLoopbackIn(), 200);
         assertArrayEquals(data, received);
-
     }
 
     @Test
     @Timeout(value = 1, unit = TimeUnit.SECONDS)
     void bulkTransferOut_timesOut() {
         var endpointOut = config.endpointLoopbackOut();
-        var endpointIn = config.endpointLoopbackIn();
 
         // The test device has an internal buffer of about 2KB for full-speed
         // and 16KB for high-speed. The first transfer should not time out.
@@ -59,14 +57,7 @@ void bulkTransferOut_timesOut() {
             }
         });
 
-        // drain data in loopback loop
-        while (true) {
-            try {
-                testDevice.transferIn(endpointIn, 200);
-            } catch (UsbTimeoutException e) {
-                break;
-            }
-        }
+        drainData(config.endpointLoopbackIn());
     }
 
     @Test

test-devices/composite-stm32/src/main.c

@@ -21,6 +21,7 @@
 // FIFO buffer for loopback data
 tu_fifo_t loopback_fifo;
 uint8_t loopback_buffer[512];
+bool delay_loopback_reset = false;
 
 // RX buffer for loopback
 uint8_t loopback_rx_buffer[64];
@@ -62,7 +63,11 @@ int main(void) {
 
 // reset device in predictable state
 void reset_buffers(void) {
-    tu_fifo_clear(&loopback_fifo);
+    if (cust_vendor_is_transmitting(EP_LOOPBACK_TX)) {
+        delay_loopback_reset = true;
+    } else {
+        tu_fifo_clear(&loopback_fifo);
+    }
 }
 
 // --- Loopback
@@ -74,6 +79,11 @@ void loopback_init(void) {
 // Check if the next transmission should be started
 void loopback_check_tx(void) {
 
+    if (delay_loopback_reset) {
+        tu_fifo_clear(&loopback_fifo);
+        delay_loopback_reset = false;
+    }
+
     tu_fifo_buffer_info_t info;
     tu_fifo_get_read_info(&loopback_fifo, &info);
 
@@ -123,19 +133,15 @@ void cust_vendor_rx_cb(uint8_t ep_addr, uint32_t recv_bytes) {
 
 // Invoked when last tx transfer finished
 void cust_vendor_tx_cb(uint8_t ep_addr, uint32_t sent_bytes) {
-    // If buffer has been reset in the mean time,
-    // we might not be able to advance it fully or at all.
-    int max_advance = tu_fifo_count(&loopback_fifo);
-    if (sent_bytes > max_advance)
-        sent_bytes = max_advance;
     if (sent_bytes > 0)
         tu_fifo_advance_read_pointer(&loopback_fifo, sent_bytes);
 
     loopback_check_tx();
     loopback_check_rx();
 
     // check ZLP
-    if ((sent_bytes & (BULK_MAX_PACKET_SIZE - 1)) == 0
+    if (sent_bytes > 0
+            && (sent_bytes & (BULK_MAX_PACKET_SIZE - 1)) == 0
             && !cust_vendor_is_transmitting(ep_addr))
         cust_vendor_start_transmit(EP_LOOPBACK_TX, NULL, 0);
 

test-devices/loopback-stm32/src/main.c

@@ -27,6 +27,7 @@
 // FIFO buffer for loopback data
 tu_fifo_t loopback_fifo;
 uint8_t loopback_buffer[BUFFER_SIZE] __attribute__ ((aligned(4)));
+bool delay_loopback_reset = false;
 
 uint16_t bulk_packet_size = 64;
 const int num_rx_packets = 2;
@@ -74,7 +75,12 @@ int main(void) {
 
 // reset device in predictable state
 void reset_buffers(void) {
-    tu_fifo_clear(&loopback_fifo);
+    if (cust_vendor_is_transmitting(EP_LOOPBACK_TX)) {
+        delay_loopback_reset = true;
+    } else {
+        tu_fifo_clear(&loopback_fifo);
+    }
+
     num_echos = 0;
 }
 
@@ -87,6 +93,11 @@ void loopback_init(void) {
 // Check if the next transmission should be started
 void loopback_check_tx(void) {
 
+    if (delay_loopback_reset) {
+        tu_fifo_clear(&loopback_fifo);
+        delay_loopback_reset = false;
+    }
+
     uint16_t n = tu_fifo_count(&loopback_fifo);
 
     if (n > 0 && !cust_vendor_is_transmitting(EP_LOOPBACK_TX)) {
@@ -143,7 +154,8 @@ void cust_vendor_tx_cb(uint8_t ep_addr, uint32_t sent_bytes) {
         loopback_check_rx();
 
         // check ZLP
-        if ((sent_bytes & (bulk_packet_size - 1)) == 0
+        if (sent_bytes > 0
+                && (sent_bytes & (bulk_packet_size - 1)) == 0
                 && !cust_vendor_is_transmitting(ep_addr)) {
             cust_vendor_start_transmit(EP_LOOPBACK_TX, NULL, 0);
             led_busy();