1 files changed, 82 insertions, 13 deletions

diff --git a/usrp/host/lib/legacy/fusb_darwin.cc b/usrp/host/lib/legacy/fusb_darwin.cc
index 05db29e80..737387b87 100644
--- a/usrp/host/lib/legacy/fusb_darwin.cc
+++ b/usrp/host/lib/legacy/fusb_darwin.cc
@@ -27,6 +27,7 @@
 // tell mld_threads to NOT use omni_threads,
 // but rather Darwin's pthreads
 #define _USE_OMNI_THREADS_
+#define DO_DEBUG 0
 
 #include <usb.h>
 #include "fusb.h"
@@ -190,13 +191,18 @@ fusb_ephandle_darwin::start ()
 	     d_endpoint, d_pipeRef, d_interface, d_interfaceRef, direction,
 	     number, interval, maxPacketSize);
 
-// set global start boolean
+  // set global start boolean
   d_started = true;
 
-// create the run thread, which allows OSX to process I/O separately
+  // lock the runBlock mutex, before creating the run thread.
+  // this guarantees that we can control execution between these 2 threads
+  d_runBlock->mutex ()->lock ();
+
+  // create the run thread, which allows OSX to process I/O separately
   d_runThread = new mld_thread (run_thread, this);
 
-// wait until the threads are -really- going
+  // wait until the run thread (and possibky read thread) are -really-
+  // going; this will unlock the mutex before waiting for a signal ()
   d_runBlock->wait ();
 
   if (usb_debug)
@@ -210,11 +216,16 @@ void
 fusb_ephandle_darwin::run_thread (void* arg)
 {
   fusb_ephandle_darwin* This = static_cast<fusb_ephandle_darwin*>(arg);
+
+  // lock the run thread running mutex; if ::stop() is called, it will
+  // first abort() the pipe then wait for the run thread to finish,
+  // via a lock() on this mutex
   mld_mutex_ptr l_runThreadRunning = This->d_runThreadRunning;
   l_runThreadRunning->lock ();
 
   mld_mutex_ptr l_readRunning = This->d_readRunning;
   mld_condition_ptr l_readBlock = This->d_readBlock;
+  mld_mutex_ptr l_readBlock_mutex = l_readBlock->mutex ();
 
   bool l_input_p = This->d_input_p;
 
@@ -237,24 +248,41 @@ fusb_ephandle_darwin::run_thread (void* arg)
   mld_thread_ptr l_rwThread = NULL;
 
   if (l_input_p) {
+    // lock the readBlock mutex, before creating the read thread.
+    // this guarantees that we can control execution between these 2 threads
+    l_readBlock_mutex->lock ();
+    // create the read thread, which just issues all of the starting
+    // async read commands, then returns
     l_rwThread = new mld_thread (read_thread, arg);
-// wait until the the rwThread is -really- going
+    // wait until the the read thread is -really- going; this will
+    // unlock the read block mutex before waiting for a signal ()
     l_readBlock->wait ();
   }
 
-// now signal the run condition to release and finish ::start()
+  // now signal the run condition to release and finish ::start().
+
+  // lock the runBlock mutex first; this will force waiting until the
+  // ->wait() command is issued in ::start()
+  mld_mutex_ptr l_run_block_mutex = This->d_runBlock->mutex ();
+  l_run_block_mutex->lock ();
+
+  // now that the lock is in place, signal the parent thread that
+  // things are running
   This->d_runBlock->signal ();
 
-// run the loop
+  // release the run_block mutex, just in case
+  l_run_block_mutex->unlock ();
+
+  // run the loop
   CFRunLoopRun ();
 
   if (l_input_p) {
-// wait for read_thread () to finish
+    // wait for read_thread () to finish, if needed
     l_readRunning->lock ();
     l_readRunning->unlock ();
   }
 
-// remove run loop stuff
+  // remove run loop stuff
   CFRunLoopRemoveSource (CFRunLoopGetCurrent (),
 			 l_cfSource, kCFRunLoopDefaultMode);
 
@@ -262,6 +290,7 @@ fusb_ephandle_darwin::run_thread (void* arg)
     fprintf (stderr, "fusb_ephandle_darwin::run_thread: finished for %s.\n",
 	     l_input_p ? "read" : "write");
 
+  // release the run thread running mutex
   l_runThreadRunning->unlock ();
 }
 
@@ -273,13 +302,27 @@ fusb_ephandle_darwin::read_thread (void* arg)
 
   fusb_ephandle_darwin* This = static_cast<fusb_ephandle_darwin*>(arg);
 
+  // before doing anything else, lock the read running mutex.  this
+  // mutex does flow control between this thread and the run_thread
   mld_mutex_ptr l_readRunning = This->d_readRunning;
   l_readRunning->lock ();
 
-// signal the read condition from run_thread() to continue
+  // signal the read condition from run_thread() to continue
+
+  // lock the readBlock mutex first; this will force waiting until the
+  // ->wait() command is issued in ::run_thread()
   mld_condition_ptr l_readBlock = This->d_readBlock;
+  mld_mutex_ptr l_read_block_mutex = l_readBlock->mutex ();
+  l_read_block_mutex->lock ();
+
+  // now that the lock is in place, signal the parent thread that
+  // things are running here
   l_readBlock->signal ();
 
+  // release the run_block mutex, just in case
+  l_read_block_mutex->unlock ();
+
+  // queue up all of the available read requests
   s_queue_ptr l_queue = This->d_queue;
   l_queue->iterate_start ();
   s_node_ptr l_node = l_queue->iterate_next ();
@@ -291,14 +334,21 @@ fusb_ephandle_darwin::read_thread (void* arg)
   if (usb_debug)
     fprintf (stderr, "fusb_ephandle_darwin::read_thread: finished.\n");
 
+  // release the read running mutex, to let the parent thread knows
+  // that this thread is finished
   l_readRunning->unlock ();
 }
 
 void
 fusb_ephandle_darwin::read_issue (s_both_ptr l_both)
 {
-  if ((! l_both) || (! d_started))
+  if ((! l_both) || (! d_started)) {
+    if (usb_debug > 4)
+      fprintf (stderr, "fusb_ephandle_darwin::read_issue: Doing nothing; "
+	       "l_both is %X; started is %s\n", (unsigned int) l_both,
+	       d_started ? "TRUE" : "FALSE");
     return;
+  }
 
 // set the node and buffer from the input "both"
   s_node_ptr l_node = l_both->node ();
@@ -328,6 +378,9 @@ fusb_ephandle_darwin::read_issue (s_both_ptr l_both)
 			  "(ReadPipeAsync%s): %s",
 			  d_transferType == kUSBInterrupt ? "" : "TO",
 			  darwin_error_str (result));
+  else if (usb_debug > 4)
+    fprintf (stderr, "fusb_ephandle_darwin::read_issue: "
+	     "Queued %X (%ld Bytes)\n", (unsigned int) l_both, bufLen);
 }
 
 void
@@ -347,6 +400,10 @@ fusb_ephandle_darwin::read_completed (void* refCon,
     fprintf (stderr, "fusb_ephandle_darwin::read_completed: "
 	     "Expected %ld bytes; read %ld.\n",
 	     l_i_size, l_size);
+  else if (usb_debug > 4)
+    fprintf (stderr, "fusb_ephandle_darwin::read_completed: "
+	     "Read %X (%ld bytes)\n",
+	     (unsigned int) l_both, l_size);
 
 // add this read to the transfer buffer
   if (l_buffer->enqueue (l_buf->buffer (), l_size) == -1) {
@@ -378,7 +435,12 @@ fusb_ephandle_darwin::write (const void* buffer, int nbytes)
 {
   UInt32 l_nbytes = (UInt32) nbytes;
 
-  if (! d_started) return (0);
+  if (! d_started) {
+    if (usb_debug)
+      fprintf (stderr, "fusb_ephandle_darwin::write: Not yet started.\n");
+
+    return (0);
+  }
 
   while (l_nbytes != 0) {
 // find out how much data to copy; limited to "d_bufLenBytes" per node
@@ -400,11 +462,11 @@ fusb_ephandle_darwin::write (const void* buffer, int nbytes)
     if (d_transferType == kUSBInterrupt)
 /* This is an interrupt pipe ... can't specify a timeout. */
       result = d_interface->WritePipeAsync
-	(d_interfaceRef, d_pipeRef, v_buffer, l_nbytes,
+	(d_interfaceRef, d_pipeRef, v_buffer, t_nbytes,
 	 (IOAsyncCallback1) write_completed, (void*) l_both);
     else
       result = d_interface->WritePipeAsyncTO
-	(d_interfaceRef, d_pipeRef, v_buffer, l_nbytes, 0, USB_TIMEOUT,
+	(d_interfaceRef, d_pipeRef, v_buffer, t_nbytes, 0, USB_TIMEOUT,
 	 (IOAsyncCallback1) write_completed, (void*) l_both);
 
     if (result != kIOReturnSuccess)
@@ -413,6 +475,10 @@ fusb_ephandle_darwin::write (const void* buffer, int nbytes)
 		     "(WritePipeAsync%s): %s",
 		     d_transferType == kUSBInterrupt ? "" : "TO",
 		     darwin_error_str (result));
+    else if (usb_debug > 4) {
+      fprintf (stderr, "fusb_ephandle_darwin::write_thread: "
+	       "Queued %X (%ld Bytes)\n", (unsigned int) l_both, t_nbytes);
+    }
     l_nbytes -= t_nbytes;
   }
 
@@ -436,6 +502,9 @@ fusb_ephandle_darwin::write_completed (void* refCon,
     fprintf (stderr, "fusb_ephandle_darwin::write_completed: "
 	     "Expected %ld bytes written; wrote %ld.\n",
 	     l_i_size, l_size);
+  else if (usb_debug > 4)
+    fprintf (stderr, "fusb_ephandle_darwin::write_completed: "
+	     "Wrote %X (%ld Bytes)\n", (unsigned int) l_both, l_size);
 
 // set buffer's # data to 0
   l_buf->n_used (0);