b100: moved usb wrapper class into b100 impl

* since its only used internally in b100

4 files changed, 262 insertions, 4 deletions

diff --git a/host/lib/usrp/b100/CMakeLists.txt b/host/lib/usrp/b100/CMakeLists.txt
index d2c33b512..bcc5ac74d 100644
--- a/host/lib/usrp/b100/CMakeLists.txt
+++ b/host/lib/usrp/b100/CMakeLists.txt
@@ -1,5 +1,5 @@
 #
-# Copyright 2011-2012 Ettus Research LLC
+# Copyright 2011-2013 Ettus Research LLC
 #
 # This program is free software: you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
@@ -31,5 +31,6 @@ IF(ENABLE_B100)
         ${CMAKE_CURRENT_SOURCE_DIR}/codec_ctrl.cpp
         ${CMAKE_CURRENT_SOURCE_DIR}/dboard_iface.cpp
         ${CMAKE_CURRENT_SOURCE_DIR}/io_impl.cpp
+        ${CMAKE_CURRENT_SOURCE_DIR}/usb_zero_copy_wrapper.cpp
     )
 ENDIF(ENABLE_B100)
diff --git a/host/lib/usrp/b100/b100_impl.cpp b/host/lib/usrp/b100/b100_impl.cpp
index 1673f5f3c..20933a2fe 100644
--- a/host/lib/usrp/b100/b100_impl.cpp
+++ b/host/lib/usrp/b100/b100_impl.cpp
@@ -1,5 +1,5 @@
 //
-// Copyright 2012 Ettus Research LLC
+// Copyright 2012-2013 Ettus Research LLC
 //
 // This program is free software: you can redistribute it and/or modify
 // it under the terms of the GNU General Public License as published by
@@ -245,7 +245,7 @@ b100_impl::b100_impl(const device_addr_t &device_addr){
     const size_t rx_lut_size = size_t(data_xport_args.cast<double>("recv_frame_size", 0.0));
     _fifo_ctrl->poke32(TOREG(SR_PADDER+0), rx_lut_size/sizeof(boost::uint32_t));
 
-    _data_transport = usb_zero_copy::make_wrapper(
+    _data_transport = usb_zero_copy_make_wrapper(
         usb_zero_copy::make(
             handle,        // identifier
             2, 6,          // IN interface, endpoint
diff --git a/host/lib/usrp/b100/b100_impl.hpp b/host/lib/usrp/b100/b100_impl.hpp
index 5f4899eb3..f81aa3568 100644
--- a/host/lib/usrp/b100/b100_impl.hpp
+++ b/host/lib/usrp/b100/b100_impl.hpp
@@ -1,5 +1,5 @@
 //
-// Copyright 2011-2012 Ettus Research LLC
+// Copyright 2011-2013 Ettus Research LLC
 //
 // This program is free software: you can redistribute it and/or modify
 // it under the terms of the GNU General Public License as published by
@@ -74,6 +74,24 @@ uhd::usrp::dboard_iface::sptr make_b100_dboard_iface(
     b100_codec_ctrl::sptr codec
 );
 
+/*!
+ * Make a wrapper around a zero copy implementation.
+ * The wrapper performs the following functions:
+ * - Pad commits to the frame boundary
+ * - Extract multiple packets on recv
+ *
+ * When enable multiple receive packets is set to true,
+ * the implementation inspects the vita length on transfers,
+ * and may split a single transfer into multiple managed buffers.
+ *
+ * \param usb_zc a usb zero copy interface object
+ * \param usb_frame_boundary bytes per frame
+ * \return a new zero copy wrapper object
+ */
+uhd::transport::zero_copy_if::sptr usb_zero_copy_make_wrapper(
+    uhd::transport::zero_copy_if::sptr usb_zc, size_t usb_frame_boundary = 512
+);
+
 //! Implementation guts
 class b100_impl : public uhd::device {
 public:
diff --git a/host/lib/usrp/b100/usb_zero_copy_wrapper.cpp b/host/lib/usrp/b100/usb_zero_copy_wrapper.cpp
new file mode 100644
index 000000000..2096e4ef4
--- /dev/null
+++ b/host/lib/usrp/b100/usb_zero_copy_wrapper.cpp
@@ -0,0 +1,239 @@
+//
+// Copyright 2011-2012 Ettus Research LLC
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+//
+
+#include <uhd/transport/usb_zero_copy.hpp>
+#include <uhd/transport/buffer_pool.hpp>
+#include <uhd/utils/byteswap.hpp>
+#include <uhd/utils/msg.hpp>
+#include <uhd/utils/tasks.hpp>
+#include <uhd/utils/atomic.hpp>
+#include <boost/foreach.hpp>
+#include <boost/make_shared.hpp>
+#include <boost/thread/mutex.hpp>
+#include <boost/thread/condition_variable.hpp>
+#include <boost/bind.hpp>
+#include <vector>
+#include <iostream>
+
+using namespace uhd;
+using namespace uhd::transport;
+
+static const boost::posix_time::time_duration AUTOFLUSH_TIMEOUT(boost::posix_time::milliseconds(1));
+
+/***********************************************************************
+ * USB zero copy wrapper - managed receive buffer
+ **********************************************************************/
+class usb_zero_copy_wrapper_mrb : public managed_recv_buffer{
+public:
+    usb_zero_copy_wrapper_mrb(void){/*NOP*/}
+
+    void release(void){
+        _mrb.reset(); //decrement ref count, other MRB's may hold a ref
+        _claimer.release();
+    }
+
+    UHD_INLINE sptr get_new(
+        managed_recv_buffer::sptr &mrb, size_t &offset_bytes,
+        const double timeout, size_t &index
+    ){
+        if (not mrb or not _claimer.claim_with_wait(timeout)) return sptr();
+
+        index++; //advances the caller's buffer
+
+        //hold a copy of the buffer shared pointer
+        _mrb = mrb;
+
+        //extract this packet's memory address and length in bytes
+        char *mem = mrb->cast<char *>() + offset_bytes;
+        const boost::uint32_t *mem32 = reinterpret_cast<const boost::uint32_t *>(mem);
+        const size_t words32 = (uhd::wtohx(mem32[0]) & 0xffff); //length in words32 (from VRT header)
+        const size_t len = words32*sizeof(boost::uint32_t); //length in bytes
+
+        //check if this receive buffer has been exhausted
+        offset_bytes += len;
+        if (offset_bytes >= mrb->size()) mrb.reset(); //drop caller's ref
+        else if (uhd::wtohx(mem32[words32]) == 0) mrb.reset();
+
+        return make(this, mem, len);
+    }
+
+private:
+    managed_recv_buffer::sptr _mrb;
+    simple_claimer _claimer;
+};
+
+/***********************************************************************
+ * USB zero copy wrapper - managed send buffer
+ **********************************************************************/
+class usb_zero_copy_wrapper_msb : public managed_send_buffer{
+public:
+    usb_zero_copy_wrapper_msb(const zero_copy_if::sptr internal, const size_t fragmentation_size):
+        _internal(internal), _fragmentation_size(fragmentation_size)
+    {
+        _ok_to_auto_flush = false;
+        _task = uhd::task::make(boost::bind(&usb_zero_copy_wrapper_msb::auto_flush, this));
+    }
+
+    ~usb_zero_copy_wrapper_msb(void)
+    {
+        //ensure the task has exited before anything auto deconstructs
+        _task.reset();
+    }
+
+    void release(void){
+        boost::mutex::scoped_lock lock(_mutex);
+        _ok_to_auto_flush = true;
+
+        //get a reference to the VITA header before incrementing
+        const boost::uint32_t vita_header = reinterpret_cast<const boost::uint32_t *>(_mem_buffer_tip)[0];
+
+        _bytes_in_buffer += size();
+        _mem_buffer_tip += size();
+
+        //extract VITA end of packet flag, we must force flush under eof conditions
+        const bool eop = (uhd::wtohx(vita_header) & (0x1 << 24)) != 0;
+        const bool full = _bytes_in_buffer >= (_last_send_buff->size() - _fragmentation_size);
+        if (eop or full){
+            _last_send_buff->commit(_bytes_in_buffer);
+            _last_send_buff.reset();
+
+            //notify the auto-flusher to restart its timed_wait
+            lock.unlock(); _cond.notify_one();
+        }
+    }
+
+    UHD_INLINE sptr get_new(const double timeout){
+        boost::mutex::scoped_lock lock(_mutex);
+        _ok_to_auto_flush = false;
+
+        if (not _last_send_buff){
+            _last_send_buff = _internal->get_send_buff(timeout);
+            if (not _last_send_buff) return sptr();
+            _mem_buffer_tip = _last_send_buff->cast<char *>();
+            _bytes_in_buffer = 0;
+        }
+
+        return make(this, _mem_buffer_tip, _fragmentation_size);
+    }
+
+private:
+    zero_copy_if::sptr _internal;
+    const size_t _fragmentation_size;
+    managed_send_buffer::sptr _last_send_buff;
+    size_t _bytes_in_buffer;
+    char *_mem_buffer_tip;
+
+    //private variables for auto flusher
+    boost::mutex _mutex;
+    boost::condition_variable _cond;
+    uhd::task::sptr _task;
+    bool _ok_to_auto_flush;
+
+    /*!
+     * The auto flusher ensures that buffers are force committed when
+     * the user has not called get_new() within a certain time window.
+     */
+    void auto_flush(void)
+    {
+        boost::mutex::scoped_lock lock(_mutex);
+        const bool timeout = not _cond.timed_wait(lock, AUTOFLUSH_TIMEOUT);
+        if (timeout and _ok_to_auto_flush and _last_send_buff and _bytes_in_buffer != 0)
+        {
+            _last_send_buff->commit(_bytes_in_buffer);
+            _last_send_buff.reset();
+        }
+    }
+};
+
+/***********************************************************************
+ * USB zero copy wrapper implementation
+ **********************************************************************/
+class usb_zero_copy_wrapper : public usb_zero_copy{
+public:
+    usb_zero_copy_wrapper(zero_copy_if::sptr usb_zc, const size_t frame_boundary):
+        _internal_zc(usb_zc),
+        _frame_boundary(frame_boundary),
+        _next_recv_buff_index(0)
+    {
+        for (size_t i = 0; i < this->get_num_recv_frames(); i++){
+            _mrb_pool.push_back(boost::make_shared<usb_zero_copy_wrapper_mrb>());
+        }
+        _the_only_msb = boost::make_shared<usb_zero_copy_wrapper_msb>(usb_zc, frame_boundary);
+    }
+
+    managed_recv_buffer::sptr get_recv_buff(double timeout){
+        //lazy flush mechanism - negative timeout
+        if (timeout < 0.0)
+        {
+            _last_recv_buff.reset();
+            while (_internal_zc->get_recv_buff()){}
+            return managed_recv_buffer::sptr();
+        }
+
+        //attempt to get a managed recv buffer
+        if (not _last_recv_buff){
+            _last_recv_buff = _internal_zc->get_recv_buff(timeout);
+            _last_recv_offset = 0; //reset offset into buffer
+        }
+
+        //get the buffer to be returned to the user
+        if (_next_recv_buff_index == _mrb_pool.size()) _next_recv_buff_index = 0;
+        return _mrb_pool[_next_recv_buff_index]->get_new(
+            _last_recv_buff, _last_recv_offset, timeout, _next_recv_buff_index
+        );
+    }
+
+    size_t get_num_recv_frames(void) const{
+        return _internal_zc->get_num_recv_frames();
+    }
+
+    size_t get_recv_frame_size(void) const{
+        return std::min(_frame_boundary, _internal_zc->get_recv_frame_size());
+    }
+
+    managed_send_buffer::sptr get_send_buff(double timeout){
+        return _the_only_msb->get_new(timeout);
+    }
+
+    size_t get_num_send_frames(void) const{
+        return _internal_zc->get_num_send_frames();
+    }
+
+    size_t get_send_frame_size(void) const{
+        return std::min(_frame_boundary, _internal_zc->get_send_frame_size());
+    }
+
+private:
+    zero_copy_if::sptr _internal_zc;
+    size_t _frame_boundary;
+    std::vector<boost::shared_ptr<usb_zero_copy_wrapper_mrb> > _mrb_pool;
+    boost::shared_ptr<usb_zero_copy_wrapper_msb> _the_only_msb;
+
+    //state for last recv buffer to create multiple managed buffers
+    managed_recv_buffer::sptr _last_recv_buff;
+    size_t _last_recv_offset;
+    size_t _next_recv_buff_index;
+};
+
+/***********************************************************************
+ * USB zero copy wrapper factory function
+ **********************************************************************/
+zero_copy_if::sptr usb_zero_copy_make_wrapper(
+    zero_copy_if::sptr usb_zc, size_t usb_frame_boundary
+){
+    return zero_copy_if::sptr(new usb_zero_copy_wrapper(usb_zc, usb_frame_boundary));
+}