libnfc/libnfc/drivers/pn532_uart.c

/*-
 * Public platform independent Near Field Communication (NFC) library
 * 
 * Copyright (C) 2009, Roel Verdult
 * 
 * This program is free software: you can redistribute it and/or modify it
 * under the terms of the GNU Lesser 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 Lesser General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>
 */

/**
 * @file pn532_uart.c
 * @brief PN532 driver using UART bus (UART, RS232, etc.)
 */

#ifdef HAVE_CONFIG_H
  #include "config.h"
#endif // HAVE_CONFIG_H

#include "../drivers.h"

#include <stdio.h>
#include <string.h>

#include "pn532_uart.h"

#include <nfc/nfc.h>
#include <nfc/nfc-messages.h>

// Bus
#include "uart.h"

#define BUFFER_LENGTH 256

#define SERIAL_DEFAULT_PORT_SPEED 115200

void pn532_uart_wakeup(const nfc_device_spec_t nds);
bool pn532_uart_check_communication(const nfc_device_spec_t nds, bool* success);

nfc_device_desc_t *
pn532_uart_pick_device (void)
{
  nfc_device_desc_t *pndd;

  if ((pndd = malloc (sizeof (*pndd)))) {
    size_t szN;

    if (!pn532_uart_list_devices (pndd, 1, &szN)) {
      DBG("%s", "pn532_uart_list_devices failed");
      return NULL;
    }

    if (szN == 0) {
      DBG("%s", "No device found");
      return NULL;
    }
  }

  return pndd;
}

bool
pn532_uart_list_devices(nfc_device_desc_t pnddDevices[], size_t szDevices, size_t *pszDeviceFound)
{
  /** @note: Due to UART bus we can't know if its really a pn532 without
  * sending some PN53x commands. But using this way to probe devices, we can
  * have serious problem with other device on this bus */
#ifndef SERIAL_AUTOPROBE_ENABLED
  (void)pnddDevices;
  (void)szDevices;
  *pszDeviceFound = 0;
  DBG("%s", "Serial auto-probing have been disabled at compile time. Skipping autoprobe.");
  return false;
#else /* SERIAL_AUTOPROBE_ENABLED */
  *pszDeviceFound = 0;

  serial_port sp;
  const char* pcPorts[] = DEFAULT_SERIAL_PORTS;
  const char* pcPort;
  int iDevice = 0;
  
  while( pcPort = pcPorts[iDevice++] ) {
    sp = uart_open(pcPort);
    DBG("Trying to find PN532 device on serial port: %s at %d bauds.", pcPort, SERIAL_DEFAULT_PORT_SPEED);

    if ((sp != INVALID_SERIAL_PORT) && (sp != CLAIMED_SERIAL_PORT))
    {
      bool bComOk;
      // Serial port claimed but we need to check if a PN532_UART is connected.
      uart_set_speed(sp, SERIAL_DEFAULT_PORT_SPEED);
      // PN532 could be powered down, we need to wake it up before line testing.
      pn532_uart_wakeup((nfc_device_spec_t)sp);
      // Check communication using "Diagnose" command, with "Comunication test" (0x00)
      if(!pn532_uart_check_communication((nfc_device_spec_t)sp, &bComOk))
        return false;
      if (!bComOk)
        continue;
      uart_close(sp);

      snprintf(pnddDevices[*pszDeviceFound].acDevice, DEVICE_NAME_LENGTH - 1, "%s (%s)", "PN532", pcPort);
      pnddDevices[*pszDeviceFound].acDevice[DEVICE_NAME_LENGTH - 1] = '\0';
      pnddDevices[*pszDeviceFound].pcDriver = PN532_UART_DRIVER_NAME;
      pnddDevices[*pszDeviceFound].pcPort = strdup(pcPort);
      pnddDevices[*pszDeviceFound].uiSpeed = SERIAL_DEFAULT_PORT_SPEED;
      DBG("Device found: %s.", pnddDevices[*pszDeviceFound].acDevice);
      (*pszDeviceFound)++;

      // Test if we reach the maximum "wanted" devices
      if((*pszDeviceFound) >= szDevices) break;
    }
#ifdef DEBUG
    if (sp == INVALID_SERIAL_PORT) DBG("Invalid serial port: %s", pcPort);
    if (sp == CLAIMED_SERIAL_PORT) DBG("Serial port already claimed: %s", pcPort);
#endif /* DEBUG */
  }
#endif /* SERIAL_AUTOPROBE_ENABLED */
  return true;
}

nfc_device_t* pn532_uart_connect(const nfc_device_desc_t* pndd)
{
  serial_port sp;
  nfc_device_t* pnd = NULL;
  bool bComOk;

  DBG("Attempt to connect to: %s at %d bauds.",pndd->pcPort, pndd->uiSpeed);
  sp = uart_open(pndd->pcPort);

  if (sp == INVALID_SERIAL_PORT) ERR("Invalid serial port: %s",pndd->pcPort);
  if (sp == CLAIMED_SERIAL_PORT) ERR("Serial port already claimed: %s",pndd->pcPort);
  if ((sp == CLAIMED_SERIAL_PORT) || (sp == INVALID_SERIAL_PORT)) return NULL;

  uart_set_speed(sp, pndd->uiSpeed);
    
  // PN532 could be powered down, we need to wake it up before line testing.
  pn532_uart_wakeup((nfc_device_spec_t)sp);
  // Check communication using "Diagnose" command, with "Comunication test" (0x00)
  if(!pn532_uart_check_communication((nfc_device_spec_t)sp, &bComOk))
      return NULL;
  if (!bComOk)
      return NULL;

  DBG("Successfully connected to: %s",pndd->pcPort);

  // We have a connection
  pnd = malloc(sizeof(nfc_device_t));
  strncpy(pnd->acName, pndd->acDevice, DEVICE_NAME_LENGTH - 1);
  pnd->acName[DEVICE_NAME_LENGTH - 1] = '\0';

  pnd->nc = NC_PN532;
  pnd->nds = (nfc_device_spec_t)sp;
  pnd->bActive = true;
  pnd->bCrc = true;
  pnd->bPar = true;
  pnd->ui8TxBits = 0;
  return pnd;
}

void pn532_uart_disconnect(nfc_device_t* pnd)
{
  uart_close((serial_port)pnd->nds);
  free(pnd);
}

bool pn532_uart_transceive(nfc_device_t* pnd, const byte_t* pbtTx, const size_t szTxLen, byte_t* pbtRx, size_t* pszRxLen)
{
  byte_t abtTxBuf[BUFFER_LENGTH] = { 0x00, 0x00, 0xff }; // Every packet must start with "00 00 ff"
  byte_t abtRxBuf[BUFFER_LENGTH];
  size_t szRxBufLen = BUFFER_LENGTH;
  size_t szPos;
  // TODO: Move this one level up for libnfc-1.6
  uint8_t ack_frame[] = { 0x00, 0x00, 0xff, 0x00, 0xff, 0x00 };

  // Packet length = data length (len) + checksum (1) + end of stream marker (1)
  abtTxBuf[3] = szTxLen;
  // Packet length checksum
  abtTxBuf[4] = BUFFER_LENGTH - abtTxBuf[3];
  // Copy the PN53X command into the packet buffer
  memmove(abtTxBuf+5,pbtTx,szTxLen);

  // Calculate data payload checksum
  abtTxBuf[szTxLen+5] = 0;
  for(szPos=0; szPos < szTxLen; szPos++) 
  {
    abtTxBuf[szTxLen+5] -= abtTxBuf[szPos+5];
  }

  // End of stream marker
  abtTxBuf[szTxLen+6] = 0;

#ifdef DEBUG
  PRINT_HEX("TX", abtTxBuf,szTxLen+7);
#endif
  int res;
  res = uart_send((serial_port)pnd->nds,abtTxBuf,szTxLen+7);
  if(res != 0) {
    ERR("%s", "Unable to transmit data. (TX)");
    pnd->iLastError = res;
    return false;
  }

  szRxBufLen = 6;
  res = uart_receive((serial_port)pnd->nds,abtRxBuf,&szRxBufLen);
  if (res != 0) {
    ERR("%s", "Unable to receive data. (RX)");
    pnd->iLastError = res;
    return false;
  }

#ifdef DEBUG
  PRINT_HEX("RX", abtRxBuf,szRxBufLen);
#endif

  // WARN: UART is a per byte reception, so you usually receive ACK and next frame the same time
  if (!pn53x_transceive_callback(pnd, abtRxBuf, szRxBufLen))
    return false;
  szRxBufLen -= sizeof(ack_frame);
  memmove(abtRxBuf, abtRxBuf+sizeof(ack_frame), szRxBufLen);

  if (szRxBufLen == 0) {
    szRxBufLen = BUFFER_LENGTH;
    do {
      delay_ms(10);
      res = uart_receive((serial_port)pnd->nds,abtRxBuf,&szRxBufLen);
    } while (res != 0 );
#ifdef DEBUG
    PRINT_HEX("RX", abtRxBuf,szRxBufLen);
#endif
  }

  // When the answer should be ignored, just return a successful result
  if(pbtRx == NULL || pszRxLen == NULL) return true;

  // Only succeed when the result is at least 00 00 FF xx Fx Dx xx .. .. .. xx 00 (x = variable)
  if(szRxBufLen < 9) {
    pnd->iLastError = DEINVAL;
    return false;
  }

#ifdef DEBUG
  PRINT_HEX("TX", ack_frame,6);
#endif
  res = uart_send((serial_port)pnd->nds,ack_frame,6);
  if (res != 0) {
    ERR("%s", "Unable to transmit data. (TX)");
    pnd->iLastError = res;
    return false;
  }

  // Remove the preceding and appending bytes 00 00 ff 00 ff 00 00 00 FF xx Fx .. .. .. xx 00 (x = variable)
  *pszRxLen = szRxBufLen - 9;
  memcpy(pbtRx, abtRxBuf+7, *pszRxLen);

  return true;
}

void
pn532_uart_wakeup(const nfc_device_spec_t nds)
{
  byte_t abtRx[BUFFER_LENGTH];
  size_t szRxLen;
  /** PN532C106 wakeup. */
  /** High Speed Unit (HSU) wake up consist to send 0x55 and wait a "long" delay for PN532 being wakeup. */
  /** After the preamble we request the PN532C106 chip to switch to "normal" mode (SAM is not used) */
  const byte_t pncmd_pn532c106_wakeup_preamble[] = { 0x55,0x55,0x00,0x00,0x00,0x00,0x00,0xff,0x03,0xfd,0xd4,0x14,0x01,0x17,0x00,0x00,0xff,0x03,0xfd,0xd4,0x14,0x01,0x17,0x00 };
#ifdef DEBUG
  PRINT_HEX("TX", pncmd_pn532c106_wakeup_preamble,sizeof(pncmd_pn532c106_wakeup_preamble));
#endif
  uart_send((serial_port)nds, pncmd_pn532c106_wakeup_preamble, sizeof(pncmd_pn532c106_wakeup_preamble));
  if(0 == uart_receive((serial_port)nds,abtRx,&szRxLen)) {
#ifdef DEBUG
    PRINT_HEX("RX", abtRx,szRxLen);
#endif
  }
}

bool
pn532_uart_check_communication(const nfc_device_spec_t nds, bool* success)
{
  byte_t abtRx[BUFFER_LENGTH];
  size_t szRxLen;
  const byte_t attempted_result[] = { 0x00,0x00,0xff,0x00,0xff,0x00,0x00,0x00,0xff,0x09,0xf7,0xD5,0x01,0x00,'l','i','b','n','f','c',0xbc,0x00};

  /** To be sure that PN532 is alive, we have put a "Diagnose" command to execute a "Communication Line Test" */
  const byte_t pncmd_communication_test[] = { 0x00,0x00,0xff,0x09,0xf7,0xd4,0x00,0x00,'l','i','b','n','f','c',0xbe,0x00 };

  *success = false;

#ifdef DEBUG
  PRINT_HEX("TX", pncmd_communication_test,sizeof(pncmd_communication_test));
#endif
  if (0 != uart_send((serial_port)nds, pncmd_communication_test, sizeof(pncmd_communication_test)))
      return false;

  if (0 != uart_receive((serial_port)nds,abtRx,&szRxLen)) {
    return false;
  }
#ifdef DEBUG
  PRINT_HEX("RX", abtRx,szRxLen);
#endif

  if(0 == memcmp(abtRx,attempted_result,sizeof(attempted_result)))
    *success = true;

  return true;
}