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//
// 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/bounded_buffer.hpp>
#include <uhd/transport/buffer_pool.hpp>
#include <uhd/utils/byteswap.hpp>
#include <uhd/utils/msg.hpp>
#include <boost/foreach.hpp>
#include <vector>
#include <iostream>
using namespace uhd::transport;
/***********************************************************************
* USB zero copy wrapper - managed receive buffer
**********************************************************************/
class usb_zero_copy_wrapper_mrb : public managed_recv_buffer{
public:
usb_zero_copy_wrapper_mrb(bounded_buffer<usb_zero_copy_wrapper_mrb *> &queue):
_queue(queue){/*NOP*/}
void release(void){
if (not _mrb) return;
_mrb.reset(); //decrement ref count, other MRB's may hold a ref
_queue.push_with_haste(this);
}
UHD_INLINE sptr get_new(managed_recv_buffer::sptr mrb, const void *mem, size_t len){
_mrb = mrb;
_mem = mem;
_len = len;
return make_managed_buffer(this);
}
private:
const void *get_buff(void) const{return _mem;}
size_t get_size(void) const{return _len;}
bounded_buffer<usb_zero_copy_wrapper_mrb *> &_queue;
const void *_mem;
size_t _len;
managed_recv_buffer::sptr _mrb;
};
/***********************************************************************
* USB zero copy wrapper - managed send buffer
**********************************************************************/
class usb_zero_copy_wrapper_msb : public managed_send_buffer{
public:
usb_zero_copy_wrapper_msb(const usb_zero_copy::sptr internal, const size_t fragmentation_size):
_internal(internal), _fragmentation_size(fragmentation_size){/*NOP*/}
void commit(size_t len){
if (len == 0) return;
//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 += len;
_mem_buffer_tip += len;
//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();
}
}
UHD_INLINE sptr get_new(const double timeout){
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_managed_buffer(this);
}
private:
void *get_buff(void) const{return reinterpret_cast<void *>(_mem_buffer_tip);}
size_t get_size(void) const{return _fragmentation_size;}
usb_zero_copy::sptr _internal;
const size_t _fragmentation_size;
managed_send_buffer::sptr _last_send_buff;
size_t _bytes_in_buffer;
char *_mem_buffer_tip;
};
/***********************************************************************
* USB zero copy wrapper implementation
**********************************************************************/
class usb_zero_copy_wrapper : public usb_zero_copy{
public:
usb_zero_copy_wrapper(sptr usb_zc, const size_t frame_boundary):
_internal_zc(usb_zc),
_frame_boundary(frame_boundary),
_available_recv_buffs(this->get_num_recv_frames()),
_mrb_pool(this->get_num_recv_frames(), usb_zero_copy_wrapper_mrb(_available_recv_buffs)),
_the_only_msb(usb_zero_copy_wrapper_msb(usb_zc, frame_boundary))
{
BOOST_FOREACH(usb_zero_copy_wrapper_mrb &mrb, _mrb_pool){
_available_recv_buffs.push_with_haste(&mrb);
}
}
managed_recv_buffer::sptr get_recv_buff(double timeout){
//attempt to get a managed recv buffer
if (not _last_recv_buff.get()){
_last_recv_buff = _internal_zc->get_recv_buff(timeout);
_last_recv_offset = 0;
}
//attempt to get a wrapper for a managed recv buffer
usb_zero_copy_wrapper_mrb *wmrb = NULL;
if (_last_recv_buff.get() and _available_recv_buffs.pop_with_timed_wait(wmrb, timeout)){
//extract this packet's memory address and length in bytes
const char *mem = _last_recv_buff->cast<const char *>() + _last_recv_offset;
const boost::uint32_t *mem32 = reinterpret_cast<const boost::uint32_t *>(mem);
const size_t len = (uhd::wtohx(mem32[0]) & 0xffff)*sizeof(boost::uint32_t); //length in bytes (from VRT header)
managed_recv_buffer::sptr recv_buff; //the buffer to be returned to the user
recv_buff = wmrb->get_new(_last_recv_buff, mem, len);
_last_recv_offset += len;
//check if this receive buffer has been exhausted
if (_last_recv_offset >= _last_recv_buff->size()) {
_last_recv_buff.reset();
}
return recv_buff;
}
//otherwise return a null sptr for failure
return managed_recv_buffer::sptr();
}
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:
sptr _internal_zc;
size_t _frame_boundary;
bounded_buffer<usb_zero_copy_wrapper_mrb *> _available_recv_buffs;
std::vector<usb_zero_copy_wrapper_mrb> _mrb_pool;
usb_zero_copy_wrapper_msb _the_only_msb;
//buffer to store partially-received VRT packets in
buffer_pool::sptr _fragment_mem;
//state for last recv buffer to create multiple managed buffers
managed_recv_buffer::sptr _last_recv_buff;
size_t _last_recv_offset;
};
/***********************************************************************
* USB zero copy wrapper factory function
**********************************************************************/
usb_zero_copy::sptr usb_zero_copy::make_wrapper(
sptr usb_zc, size_t usb_frame_boundary
){
return sptr(new usb_zero_copy_wrapper(usb_zc, usb_frame_boundary));
}
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