VILLASnode/fpga/lib/ips/fifo.cpp

/* FIFO related helper functions
 *
 * These functions present a simpler interface to Xilinx' FIFO driver (XLlFifo_*)
 *
 * Author: Steffen Vogel <post@steffenvogel.de>
 * Author: Daniel Krebs <github@daniel-krebs.net>
 * SPDX-FileCopyrightText: 2017 Steffen Vogel <post@steffenvogel.de>
 * SPDX-License-Identifier: Apache-2.0
 */

#include <unistd.h>

#include <xilinx/xllfifo.h>
#include <xilinx/xstatus.h>

#include <villas/fpga/ips/fifo.hpp>
#include <villas/fpga/ips/intc.hpp>

using namespace villas::fpga::ip;

bool Fifo::init() {
  XLlFifo_Config fifo_cfg;

  try {
    // If this throws an exception, then there's no AXI4 data interface
    fifo_cfg.Axi4BaseAddress = getBaseAddr(axi4Memory);
    fifo_cfg.Datainterface = 1;
  } catch (const std::out_of_range &) {
    fifo_cfg.Datainterface = 0;
  }

  if (XLlFifo_CfgInitialize(&xFifo, &fifo_cfg, getBaseAddr(registerMemory)) !=
      XST_SUCCESS)
    return false;

  if (irqs.find(irqName) == irqs.end()) {
    logger->error("IRQ '{}' not found but required", irqName);
    return false;
  }

  // Receive complete IRQ
  XLlFifo_IntEnable(&xFifo, XLLF_INT_RC_MASK);
  irqs[irqName].irqController->enableInterrupt(irqs[irqName], false);

  return true;
}

bool Fifo::stop() {
  // Receive complete IRQ
  XLlFifo_IntDisable(&xFifo, XLLF_INT_RC_MASK);
  irqs[irqName].irqController->disableInterrupt(irqs[irqName]);

  return true;
}

size_t Fifo::write(const void *buf, size_t len) {

  uint32_t tdfv;

  tdfv = XLlFifo_TxVacancy(&xFifo);
  if (tdfv < len)
    return -1;

  // Buf has to be re-casted because Xilinx driver doesn't use const
  XLlFifo_Write(&xFifo, (void *)buf, len);
  XLlFifo_TxSetLen(&xFifo, len);

  return len;
}

size_t Fifo::read(void *buf, size_t len) {
  size_t nextlen = 0;
  size_t rxlen;

  while (!XLlFifo_IsRxDone(&xFifo))
    irqs[irqName].irqController->waitForInterrupt(irqs[irqName]);

  XLlFifo_IntClear(&xFifo, XLLF_INT_RC_MASK);

  // Get length of next frame
  rxlen = XLlFifo_RxGetLen(&xFifo);
  nextlen = std::min(rxlen, len);

  // Read from FIFO
  XLlFifo_Read(&xFifo, buf, nextlen);

  return nextlen;
}

static char n1[] = "fifo";
static char d1[] = "Xilinx's AXI4 FIFO data mover";
static char v1[] = "xilinx.com:ip:axi_fifo_mm_s:";
static NodePlugin<Fifo, n1, d1, v1> p1;

static char n2[] = "fifo_data";
static char d2[] = "Xilinx's AXI4 data stream FIFO";
static char v2[] = "xilinx.com:ip:axis_data_fifo:";
static NodePlugin<FifoData, n2, d2, v2> p2;