uhd

//

// Copyright 2010 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 "libusb1_base.hpp"

#include <uhd/transport/usb_zero_copy.hpp>

#include <uhd/utils/assert.hpp>

#include <boost/asio.hpp>

#include <boost/format.hpp>

#include <iostream>

#include <iomanip>

using namespace uhd::transport;

const int libusb_debug_level = 0;

const int libusb_timeout = 0;

/***********************************************************************

 * Helper functions

 *

 * Print to stdout the values of a libusb_transfer struct

 ***********************************************************************/

void pp_transfer(libusb_transfer *lut)

{

    std::cout << "Libusb transfer"       << std::endl;

    std::cout << "    flags:         0x" << std::hex << (unsigned int) lut->flags << std::endl;

    std::cout << "    endpoint:      0x" << std::hex << (unsigned int) lut->endpoint << std::endl;

    std::cout << "    type:          0x" << std::hex << (unsigned int) lut->type << std::endl;

    std::cout << "    timeout:       "   << std::dec << lut->timeout << std::endl;

    std::cout << "    status:        0x" << std::hex << lut->status << std::endl;

    std::cout << "    length:        "   << std::dec << lut->length << std::endl;

    std::cout << "    actual_length: "   << std::dec << lut->actual_length << std::endl;

}

/***********************************************************************

 * USB asynchronous phony zero_copy endpoint

 *   This endpoint implementation provides asynchronous I/O to libusb-1.0

 *   devices. Each endpoint is directional and two can be combined to

 *   create a bidirectional interface. It is a zero copy implementation

 *   with respect to libusb, however, each send and recv requires a copy

 *   operation from kernel to userspace; this is due to the usbfs

 *   interface provided by the kernel. 

 **********************************************************************/

class usb_endpoint {

private:

    libusb_device_handle *_dev_handle;

    libusb_context *_ctx;

    int  _endpoint;

    bool _input;

    size_t _transfer_size;

    size_t _num_transfers;

    // Transfer state lists (transfers are free, pending, or completed)

    std::list<libusb_transfer *>  _free_list;

    std::list<libusb_transfer *>  _pending_list;

    std::list<libusb_transfer *>  _completed_list;

    // Calls for processing asynchronous I/O 

    libusb_transfer *allocate_transfer(int buff_len);

    bool cancel(libusb_transfer *lut);

    bool cancel_all();

    bool reap_pending_list();

    bool reap_pending_list_timeout();

    bool reap_completed_list();

    // Transfer state manipulators 

    void free_list_add(libusb_transfer *lut);

    void pending_list_add(libusb_transfer *lut);

    void completed_list_add(libusb_transfer *lut);

    libusb_transfer *free_list_get();

    libusb_transfer *completed_list_get();

    bool pending_list_remove(libusb_transfer *lut);

    // Debug use

    void print_transfer_status(libusb_transfer *lut);

public:

    usb_endpoint(libusb_device_handle *dev_handle,

                 libusb_context *ctx, int endpoint, bool input,

                 size_t transfer_size, size_t num_transfers);

    ~usb_endpoint();

    // Exposed interface for submitting / retrieving transfer buffers

    bool submit(libusb_transfer *lut);

    libusb_transfer *get_completed_transfer();

    libusb_transfer *get_free_transfer();

    //Callback use only

    void callback_handle_transfer(libusb_transfer *lut);

};

/*

 * Callback function called when submitted transfers complete.

 * The endpoint upon which the transfer is part of is recovered

 * and the transfer moved from pending to completed state.

 * Callbacks occur during the reaping calls where libusb_handle_events()

 * is used. The callback only modifies the transfer state by moving

 * it from the pending to completed status list.

 * \param lut pointer to libusb_transfer

 */

static void callback(libusb_transfer *lut)

{

    usb_endpoint *endpoint = (usb_endpoint *) lut->user_data; 

    endpoint->callback_handle_transfer(lut);

}

/*

 * Accessor call to allow list access from callback space

 * \param pointer to libusb_transfer

 */

void usb_endpoint::callback_handle_transfer(libusb_transfer *lut)

{

    if (!pending_list_remove(lut)) {

        std::cerr << "USB: pending remove failed" << std::endl;

        return;

    }

    completed_list_add(lut);    

}

/*

 * Constructor

 * Allocate libusb transfers and mark as free.  For IN endpoints,

 * submit the transfers so that they're ready to return when

 * data is available. 

 */

usb_endpoint::usb_endpoint(libusb_device_handle *dev_handle,

                          libusb_context *ctx, int endpoint, bool input,

                          size_t transfer_size, size_t num_transfers)

    : _dev_handle(dev_handle),

      _ctx(ctx), _endpoint(endpoint), _input(input),

      _transfer_size(transfer_size), _num_transfers(num_transfers)

{

    unsigned int i;

    for (i = 0; i < _num_transfers; i++) {

        free_list_add(allocate_transfer(_transfer_size));

        if (_input)

            submit(free_list_get());

    }

}

/*

 * Destructor

 * Make sure all the memory is freed. Cancel any pending transfers.

 * When all completed transfers are moved to the free list, release

 * the transfers. Libusb will deallocate the data buffer held by

 * each transfer.

 */

usb_endpoint::~usb_endpoint()

{

    cancel_all();

    while (!_pending_list.empty()) {

        if (!reap_pending_list())

            std::cerr << "error: destructor failed to reap" << std::endl;

    }

    while (!_completed_list.empty()) {

        if (!reap_completed_list())

            std::cerr << "error: destructor failed to reap" << std::endl;

    }

    while (!_free_list.empty()) {

        libusb_free_transfer(free_list_get());

    }

}

/*

 * Allocate a libusb transfer 

 * The allocated transfer - and buffer it contains - is repeatedly

 * submitted, reaped, and reused and should not be freed until shutdown.

 * \param buff_len size of the individual buffer held by each transfer

 * \return pointer to an allocated libusb_transfer

 */

libusb_transfer *usb_endpoint::allocate_transfer(int buff_len)

{

    libusb_transfer *lut = libusb_alloc_transfer(0);

    unsigned char *buff = new unsigned char[buff_len];

    unsigned int endpoint = ((_endpoint & 0x7f) | (_input ? 0x80 : 0));

    libusb_fill_bulk_transfer(lut,                // transfer

                              _dev_handle,        // dev_handle

                              endpoint,           // endpoint

                              buff,               // buffer

                              buff_len,           // length

                              callback,           // callback

                              this,               // user_data

                              0);                 // timeout

    return lut;

}

/*

 * Asynchonous transfer submission

 * Submit a libusb transfer to libusb add pending status

 * \param lut pointer to libusb_transfer

 * \return true on success or false on error 

 */

bool usb_endpoint::submit(libusb_transfer *lut)

{

    int retval;

    if ((retval = libusb_submit_transfer(lut)) < 0) {

        std::cerr << "error: libusb_submit_transfer: " << retval << std::endl;

        return false;

    }

    pending_list_add(lut);

    return true;

}

/*

 * Cancel a pending transfer 

 * Search the pending list for the transfer and cancel if found.

 * \param lut pointer to libusb_transfer to cancel

 * \return true on success or false if transfer is not found

 *

 * Note: success only indicates submission of cancelation request.

 * Sucessful cancelation is not known until the callback occurs.

 */

bool usb_endpoint::cancel(libusb_transfer *lut)

{

    std::list<libusb_transfer*>::iterator iter;

    for (iter = _pending_list.begin(); iter != _pending_list.end(); iter++) {

        if (*iter == lut) { 

            libusb_cancel_transfer(lut); 

            return true;

        }

    }

    return false;

}

/*

 * Cancel all pending transfers 

 * \return bool true if cancelation request is submitted

 *

 * Note: success only indicates submission of cancelation request.

 * Sucessful cancelation is not known until the callback occurs.

 */

bool usb_endpoint::cancel_all()

{

    std::list<libusb_transfer*>::iterator iter;

    for (iter = _pending_list.begin(); iter != _pending_list.end(); iter++) {

        if (libusb_cancel_transfer(*iter) < 0) {

            std::cerr << "error: libusb_cancal_transfer() failed" << std::endl;

            return false;

        }

    }

    return true;

}

/*

 * Reap completed transfers

 * return true if at least one transfer was reaped, false otherwise. 

 * Check completed transfers for errors and mark as free. This is a

 * blocking call. 

 * \return bool true if a libusb transfer is reaped, false otherwise

 */

bool usb_endpoint::reap_completed_list()

{

    libusb_transfer *lut;

    if (_completed_list.empty()) {

        if (!reap_pending_list_timeout())

            return false;

    }

    while (!_completed_list.empty()) {

        lut = completed_list_get();

        print_transfer_status(lut);

        free_list_add(lut);

    }

    return true;

}

/*

 * Print status errors of a completed transfer

 * \param lut pointer to an libusb_transfer

 */

void usb_endpoint::print_transfer_status(libusb_transfer *lut)

{

    switch (lut->status) {

    case LIBUSB_TRANSFER_COMPLETED:

        if (lut->actual_length < lut->length) {

            std::cerr << "USB: transfer completed with short write,"

                      << " length = " << lut->length

                      << " actual = " << lut->actual_length << std::endl;

        }

        if ((lut->actual_length < 0) || (lut->length < 0)) {

            std::cerr << "USB: transfer completed with invalid response"

                      << std::endl;

        }

        break;

    case LIBUSB_TRANSFER_CANCELLED:

        break;

    case LIBUSB_TRANSFER_NO_DEVICE:

        std::cerr << "USB: device was disconnected" << std::endl;

        break;

    case LIBUSB_TRANSFER_OVERFLOW:

        std::cerr << "USB: device sent more data than requested" << std::endl;

        break;

    case LIBUSB_TRANSFER_TIMED_OUT:

        std::cerr << "USB: transfer timed out" << std::endl;

        break;

    case LIBUSB_TRANSFER_STALL:

        std::cerr << "USB: halt condition detected (stalled)" << std::endl;

        break;

    case LIBUSB_TRANSFER_ERROR:

        std::cerr << "USB: transfer failed" << std::endl;

        break;

    default:

        std::cerr << "USB: received unknown transfer status" << std::endl;

    }

}

/*

 * Reap pending transfers without timeout 

 * This is a blocking call. Reaping submitted transfers is

 * handled by libusb and the assigned callback function.

 * Block until at least one transfer is reaped.

 * \return true true if a transfer was reaped or false otherwise

 */

bool usb_endpoint::reap_pending_list()

{

    int retval;

    if ((retval = libusb_handle_events(_ctx)) < 0) {

        std::cerr << "error: libusb_handle_events: " << retval << std::endl;

        return false;

    }

    return true;

}

/*

 * Reap pending transfers with timeout 

 * This call blocks until a transfer is reaped or timeout.

 * Reaping submitted transfers is handled by libusb and the

 * assigned callback function. Block until at least one

 * transfer is reaped or timeout occurs.

 * \return true if a transfer was reaped or false otherwise

 */

bool usb_endpoint::reap_pending_list_timeout()

{

    int retval;

    timeval tv;

    tv.tv_sec = 0;

    tv.tv_usec = 100000; //100ms

    size_t pending_list_size = _pending_list.size();

    if ((retval = libusb_handle_events_timeout(_ctx, &tv)) < 0) {

        std::cerr << "error: libusb_handle_events: " << retval << std::endl;

        return false;

    }

    if (_pending_list.size() < pending_list_size) {

        return true;

    }

    else {

        return false;

    }

}

/*

 * Get a free transfer

 * The transfer has an empty data bufer for OUT requests 

 * \return pointer to a libusb_transfer

 */

libusb_transfer *usb_endpoint::get_free_transfer()

{

    if (_free_list.empty()) {

        if (!reap_completed_list())

            return NULL; 

    }

    return free_list_get();

}

/*

 * Get a completed transfer 

 * The transfer has a full data buffer for IN requests

 * \return pointer to libusb_transfer

 */

libusb_transfer *usb_endpoint::get_completed_transfer()

{

    if (_completed_list.empty()) {

        if (!reap_pending_list_timeout())

            return NULL; 

    }

    return completed_list_get();

}

/*

 * List operations 

 */

void usb_endpoint::free_list_add(libusb_transfer *lut)

{

    _free_list.push_back(lut);

}

void usb_endpoint::pending_list_add(libusb_transfer *lut)

{

    _pending_list.push_back(lut);

}

void usb_endpoint::completed_list_add(libusb_transfer *lut)

{

    _completed_list.push_back(lut);

}

/*

 * Free and completed lists don't have ordered content 

 * Pop transfers from the front as needed

 */

libusb_transfer *usb_endpoint::free_list_get()

{

    libusb_transfer *lut;

    if (_free_list.size() == 0) {

        return NULL; 

    }

    else { 

        lut = _free_list.front();

        _free_list.pop_front();

        return lut;

    }

}

/*

 * Free and completed lists don't have ordered content 

 * Pop transfers from the front as needed

 */

libusb_transfer *usb_endpoint::completed_list_get()

{

    libusb_transfer *lut;

    if (_completed_list.empty()) {

        return NULL;

    }

    else { 

        lut = _completed_list.front();

        _completed_list.pop_front();

        return lut;

    }

}

/*

 * Search and remove transfer from pending list

 * Assuming that the callbacks occur in order, the front element

 * should yield the correct transfer. If not, then something else

 * is going on. If no transfers match, then something went wrong.

 */

bool usb_endpoint::pending_list_remove(libusb_transfer *lut)

{

    std::list<libusb_transfer*>::iterator iter;

    for (iter = _pending_list.begin(); iter != _pending_list.end(); iter++) {

        if (*iter == lut) { 

            _pending_list.erase(iter);

            return true;

        }

    }

    return false;

}

/***********************************************************************

 * Managed buffers 

 **********************************************************************/

/*

 * Libusb managed receive buffer

 * Construct a recv buffer from a libusb transfer. The memory held by

 * the libusb transfer is exposed through the managed buffer interface.

 * Upon destruction, the transfer and buffer are resubmitted to the

 * endpoint for further use. 

 */

class libusb_managed_recv_buffer_impl : public managed_recv_buffer {

public:

    libusb_managed_recv_buffer_impl(libusb_transfer *lut,

                                    usb_endpoint *endpoint)

        : _buff(lut->buffer, lut->length)

    {

        _lut = lut;

        _endpoint = endpoint;

    }

    ~libusb_managed_recv_buffer_impl()

    {

       if (!_endpoint->submit(_lut))

           std::cerr << "USB: failed to submit IN transfer" << std::endl;

    }

private:

    const boost::asio::const_buffer &get() const

    {

        return _buff; 

    }

    libusb_transfer *_lut;

    usb_endpoint *_endpoint;

    const boost::asio::const_buffer _buff;

};

/*

 * Libusb managed send buffer

 * Construct a send buffer from a libusb transfer. The memory held by

 * the libusb transfer is exposed through the managed buffer interface.

 * Committing the buffer will set the data length and submit the buffer

 * to the endpoint. Submitting a buffer multiple times or destroying

 * the buffer before committing is an error. For the latter, the transfer

 * is returned to the endpoint with no data for reuse.

 */

class libusb_managed_send_buffer_impl : public managed_send_buffer {

public:

    libusb_managed_send_buffer_impl(libusb_transfer *lut,

                                    usb_endpoint *endpoint,

                                    size_t buff_size)

        : _buff(lut->buffer, buff_size), _committed(false)

    {

        _lut = lut;

        _endpoint = endpoint;

    }

    ~libusb_managed_send_buffer_impl()

    {

        if (!_committed) {

            _lut->length = 0;

            _lut->actual_length = 0;

            _endpoint->submit(_lut);

        }

    }

    ssize_t commit(size_t num_bytes)

    {

        if (_committed) {

            std::cerr << "UHD: send buffer already committed" << std::endl;

            return 0;

        }

        UHD_ASSERT_THROW(num_bytes <= boost::asio::buffer_size(_buff));

        _lut->length = num_bytes;

        _lut->actual_length = 0;

        if (_endpoint->submit(_lut)) {

            _committed = true;

            return num_bytes;

        }

        else {

            return 0;

        }

    }

private:

    const boost::asio::mutable_buffer &get() const

    {

        return _buff; 

    }

    libusb_transfer *_lut;

    usb_endpoint *_endpoint;

    const boost::asio::mutable_buffer _buff;

    bool _committed;

};

/***********************************************************************

 * USB zero_copy device class

 **********************************************************************/

class libusb_zero_copy_impl : public usb_zero_copy

{

private:

    usb_endpoint          *_rx_ep;

    usb_endpoint          *_tx_ep;

    // Maintain libusb values

    libusb_context       *_rx_ctx;

    libusb_context       *_tx_ctx;

    libusb_device_handle *_rx_dev_handle;

    libusb_device_handle *_tx_dev_handle;

    size_t _recv_buff_size;

    size_t _send_buff_size;

    size_t _num_frames;

public:

    typedef boost::shared_ptr<libusb_zero_copy_impl> sptr;

    libusb_zero_copy_impl(usb_device_handle::sptr handle,

                          unsigned int rx_endpoint,

                          unsigned int tx_endpoint,

                          size_t recv_buff_size,

                          size_t send_buff_size);

    ~libusb_zero_copy_impl();

    managed_recv_buffer::sptr get_recv_buff(void);

    managed_send_buffer::sptr get_send_buff(void);

    size_t get_num_recv_frames(void) const { return _num_frames; }

    size_t get_num_send_frames(void) const { return _num_frames; }

};

/*

 * Constructor

 * Initializes libusb, opens devices, and sets up interfaces for I/O.

 * Finally, creates endpoints for asynchronous I/O. 

 */

libusb_zero_copy_impl::libusb_zero_copy_impl(usb_device_handle::sptr handle,

                                             unsigned int rx_endpoint,

                                             unsigned int tx_endpoint,

                                             size_t buff_size,

                                             size_t block_size)

 : _rx_ctx(NULL), _tx_ctx(NULL), _rx_dev_handle(NULL), _tx_dev_handle(NULL),

   _recv_buff_size(block_size), _send_buff_size(block_size),

   _num_frames(buff_size / block_size)

{

    // Initialize libusb with separate contexts to allow

    // thread safe operation of transmit and receive 

    libusb::init(&_rx_ctx, libusb_debug_level);

    libusb::init(&_tx_ctx, libusb_debug_level);

    UHD_ASSERT_THROW((_rx_ctx != NULL) && (_tx_ctx != NULL));

    // Find and open the libusb_device corresponding to the

    // given handle and return the libusb_device_handle

    // that can be used for I/O purposes.

    _rx_dev_handle = libusb::open_device(_rx_ctx, handle);

    _tx_dev_handle = libusb::open_device(_tx_ctx, handle);

    // Open USB interfaces for tx/rx using magic values.

    // IN interface:      2

    // OUT interface:     1

    // Control interface: 0

    libusb::open_interface(_rx_dev_handle, 2);

    libusb::open_interface(_tx_dev_handle, 1);

    _rx_ep = new usb_endpoint(_rx_dev_handle,  // libusb device_handle

                              _rx_ctx,         // libusb context

                              rx_endpoint,     // USB endpoint number

                              true,            // IN endpoint

                              _recv_buff_size, // buffer size per transfer 

                              _num_frames);    // number of libusb transfers

    _tx_ep = new usb_endpoint(_tx_dev_handle,  // libusb device_handle

                              _tx_ctx,         // libusb context

                              tx_endpoint,     // USB endpoint number

                              false,           // OUT endpoint

                              _send_buff_size, // buffer size per transfer

                              _num_frames);    // number of libusb transfers

}

libusb_zero_copy_impl::~libusb_zero_copy_impl()

{

    delete _rx_ep;

    delete _tx_ep; 

    libusb_close(_rx_dev_handle);

    libusb_close(_tx_dev_handle);

    libusb_exit(_rx_ctx);

    libusb_exit(_tx_ctx);

}

/*

 * Construct a managed receive buffer from a completed libusb transfer

 * (happy with buffer full of data) obtained from the receive endpoint.

 * Return empty pointer if no transfer is available (timeout or error).

 * \return pointer to a managed receive buffer 

 */

managed_recv_buffer::sptr libusb_zero_copy_impl::get_recv_buff()

{

    libusb_transfer *lut = _rx_ep->get_completed_transfer();

    if (lut == NULL) {

        return managed_recv_buffer::sptr();

    }

    else {

        return managed_recv_buffer::sptr(

            new libusb_managed_recv_buffer_impl(lut,

                                                _rx_ep));

    }

}

/*

 * Construct a managed send buffer from a free libusb transfer (with

 * empty buffer). Return empty pointer of no transfer is available

 * (timeout or error).

 * \return pointer to a managed send buffer 

 */

managed_send_buffer::sptr libusb_zero_copy_impl::get_send_buff()

{

    libusb_transfer *lut = _tx_ep->get_free_transfer();

    if (lut == NULL) {

        return managed_send_buffer::sptr();

    }

    else {

        return managed_send_buffer::sptr(

            new libusb_managed_send_buffer_impl(lut,

                                                _tx_ep,

                                                _send_buff_size));

    }

}

/***********************************************************************

 * USB zero_copy make functions

 **********************************************************************/

usb_zero_copy::sptr usb_zero_copy::make(usb_device_handle::sptr handle,

                                        unsigned int rx_endpoint,

                                        unsigned int tx_endpoint,

                                        size_t buff_size,

                                        size_t block_size)

{

    return sptr(new libusb_zero_copy_impl(handle,

                                          rx_endpoint,

                                          tx_endpoint,

                                          buff_size, 

                                          block_size));

}