libnfc/libnfc/drivers/pn532_uart.c

/*-
 * Public platform independent Near Field Communication (NFC) library
 * 
 * Copyright (C) 2010, Roel Verdult, Romuald Conty
 * Copyright (C) 2011, Romuald Conty, Romain Tartière
 * 
 * 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.)
 */

/* vim: set ts=2 sw=2 et: */

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

#include "libnfc/drivers.h"

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

#include "pn532_uart.h"

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

#include "uart.h"
#include "libnfc/nfc-internal.h"
#include "libnfc/chips/pn53x.h"
#include "libnfc/chips/pn53x-internal.h"

#define SERIAL_DEFAULT_PORT_SPEED 115200

// TODO Move this one level up for libnfc-1.6
static const byte_t ack_frame[] = { 0x00, 0x00, 0xff, 0x00, 0xff, 0x00 };

void    pn532_uart_ack (nfc_device_t * pnd);
// void    pn532_uart_wakeup (const nfc_device_spec_t nds);
bool    pn532_uart_check_communication (nfc_device_t *pnd);

struct pn532_uart_data {
  serial_port port;
};
  
bool
pn532_uart_probe (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;
  char **pcPorts = uart_list_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)) {
      // Serial port claimed but we need to check if a PN532_UART is connected.
      uart_set_speed (sp, SERIAL_DEFAULT_PORT_SPEED);

      nfc_device_t nd;
      nd.driver = &pn532_uart_driver;
      nd.driver_data = malloc(sizeof(struct pn532_uart_data));
      ((struct pn532_uart_data*)(nd.driver_data))->port = sp;
      nd.chip_data = malloc(sizeof(struct pn53x_data));
      ((struct pn53x_data*)(nd.chip_data))->type = PN532;
      ((struct pn53x_data*)(nd.chip_data))->state = SLEEP;

      // PN532 could be powered down, we need to wake it up before line testing.
      // TODO pn532_uart_wakeup ((nfc_device_spec_t) sp);
      // Check communication using "Diagnose" command, with "Communication test" (0x00)
      bool res = pn532_uart_check_communication (&nd);
      free(nd.driver_data);
      free(nd.chip_data);
      if(!res)
        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 */
  }
  free (pcPorts);
#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;

  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);

  // 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->driver_data = malloc(sizeof(struct pn532_uart_data));
  ((struct pn532_uart_data*)(pnd->driver_data))->port = sp;
  pnd->chip_data = malloc(sizeof(struct pn53x_data));
  ((struct pn53x_data*)(pnd->chip_data))->type = PN532;
  ((struct pn53x_data*)(pnd->chip_data))->state = SLEEP;
  pnd->driver = &pn532_uart_driver;

  // Check communication using "Diagnose" command, with "Communication test" (0x00)
  if (!pn532_uart_check_communication (pnd))
    return NULL;

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

  return pnd;
}

void
pn532_uart_disconnect (nfc_device_t * pnd)
{
  uart_close (((struct pn532_uart_data*)(pnd->driver_data))->port);
  free (pnd->driver_data);
  free (pnd->chip_data);
  free (pnd);
}

#define PN532_BUFFER_LEN (PN53x_EXTENDED_FRAME__DATA_MAX_LEN + PN53x_EXTENDED_FRAME__OVERHEAD)
bool
pn532_uart_send (nfc_device_t * pnd, const byte_t * pbtData, const size_t szData)
{
  DBG ("state: %d (SLEEP: %d, NORMAL: %d, EXECUTE: %d)", ((struct pn53x_data*)(pnd->chip_data))->state, SLEEP, NORMAL, EXECUTE);
  if (((struct pn53x_data*)(pnd->chip_data))->state == SLEEP) {
//  if (1) {
    /** PN532C106 wakeup. */
    /** High Speed Unit (HSU) wake up consist to send 0x55 and wait a "long" delay for PN532 being wakeup. */
    const byte_t pn532_wakeup_preamble[] = { 0x55, 0x55, 0x00, 0x00, 0x00 };
//, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 };
    uart_send (((struct pn532_uart_data*)(pnd->driver_data))->port, pn532_wakeup_preamble, sizeof (pn532_wakeup_preamble));
    ((struct pn53x_data*)(pnd->chip_data))->state = NORMAL; // PN532 should now be awake
    // According to PN532 application note, C106 appendix: to go out Low Vbat mode and enter in normal mode we need to send a SAMConfiguration command
    if (!pn53x_SAMConfiguration (pnd, 0x01)) {
      return false;
    }
  }

  byte_t  abtTxBuf[PN532_BUFFER_LEN] = { 0x00, 0x00, 0xff };       // Every packet must start with "00 00 ff"

  pnd->iLastCommand = pbtData[0];
  size_t szFrame = 0;

  if (szData <= PN53x_NORMAL_FRAME__DATA_MAX_LEN) {
    // LEN - Packet length = data length (len) + checksum (1) + end of stream marker (1)
    abtTxBuf[3] = szData + 1;
    // LCS - Packet length checksum
    abtTxBuf[4] = 256 - (szData + 1);
    // TFI
    abtTxBuf[5] = 0xD4;
    // DATA - Copy the PN53X command into the packet buffer
    memcpy (abtTxBuf + 6, pbtData, szData);

    // DCS - Calculate data payload checksum
    byte_t btDCS = (256 - 0xD4);
    for (size_t szPos = 0; szPos < szData; szPos++) {
      btDCS -= pbtData[szPos];
    }
    abtTxBuf[6 + szData] = btDCS;

    // 0x00 - End of stream marker
    abtTxBuf[szData + 7] = 0x00;

    szFrame = szData + PN53x_NORMAL_FRAME__OVERHEAD;
  } else {
    // FIXME: Build extended frame
    abort();
  }

  int res = uart_send (((struct pn532_uart_data*)(pnd->driver_data))->port, abtTxBuf, szFrame);
  if (res != 0) {
    ERR ("%s", "Unable to transmit data. (TX)");
    pnd->iLastError = res;
    return false;
  }

  byte_t abtRxBuf[6];
  res = uart_receive (((struct pn532_uart_data*)(pnd->driver_data))->port, abtRxBuf, 6);
  if (res != 0) {
    ERR ("%s", "Unable to read ACK");
    pnd->iLastError = res;
    return false;
  }

  if (pn53x_check_ack_frame_callback (pnd, abtRxBuf, sizeof(abtRxBuf))) {
    ((struct pn53x_data*)(pnd->chip_data))->state = EXECUTE;
  } else {
    return false;
  }
  return true;
}

int
pn532_uart_receive (nfc_device_t * pnd, byte_t * pbtData, const size_t szDataLen)
{
  byte_t  abtRxBuf[5];
  size_t len;

  int res = uart_receive (((struct pn532_uart_data*)(pnd->driver_data))->port, abtRxBuf, 5);
  if (res != 0) {
    ERR ("%s", "Unable to receive data. (RX)");
    pnd->iLastError = res;
    return -1;
  }

  const byte_t pn53x_preamble[3] = { 0x00, 0x00, 0xff };
  if (0 != (memcmp (abtRxBuf, pn53x_preamble, 3))) {
    ERR ("%s", "Frame preamble+start code mismatch");
    pnd->iLastError = DEIO;
    return -1;
  }

  if ((0x01 == abtRxBuf[3]) && (0xff == abtRxBuf[4])) {
    // Error frame
    uart_receive (((struct pn532_uart_data*)(pnd->driver_data))->port, abtRxBuf, 3);
    ERR ("%s", "Application level error detected");
    pnd->iLastError = DEISERRFRAME;
    return -1;
  } else if ((0xff == abtRxBuf[3]) && (0xff == abtRxBuf[4])) {
    // Extended frame
    // FIXME: Code this
    abort ();
  } else {
    // Normal frame
    if (256 != (abtRxBuf[3] + abtRxBuf[4])) {
      // TODO: Retry
      ERR ("%s", "Length checksum mismatch");
      pnd->iLastError = DEIO;
      return -1;
    }

    // abtRxBuf[3] (LEN) include TFI + (CC+1)
    len = abtRxBuf[3] - 2;
  }

  if (len > szDataLen) {
    ERR ("Unable to receive data: buffer too small. (szDataLen: %zu, len: %zu)", szDataLen, len);
    pnd->iLastError = DEIO;
    return -1;
  }

  // TFI + PD0 (CC+1)
  res = uart_receive (((struct pn532_uart_data*)(pnd->driver_data))->port, abtRxBuf, 2);
  if (res != 0) {
    ERR ("%s", "Unable to receive data. (RX)");
    pnd->iLastError = res;
    return -1;
  }

  if (abtRxBuf[0] != 0xD5) {
    ERR ("%s", "TFI Mismatch");
    pnd->iLastError = DEIO;
    return -1;
  }

  if (abtRxBuf[1] != pnd->iLastCommand + 1) {
    ERR ("%s", "Command Code verification failed");
    pnd->iLastError = DEIO;
    return -1;
  }

  if (len) {
    res = uart_receive (((struct pn532_uart_data*)(pnd->driver_data))->port, pbtData, len);
    if (res != 0) {
      ERR ("%s", "Unable to receive data. (RX)");
      pnd->iLastError = res;
      return -1;
    }
  }

  res = uart_receive (((struct pn532_uart_data*)(pnd->driver_data))->port, abtRxBuf, 2);
  if (res != 0) {
    ERR ("%s", "Unable to receive data. (RX)");
    pnd->iLastError = res;
    return -1;
  }

  byte_t btDCS = (256 - 0xD5);
  btDCS -= pnd->iLastCommand + 1;
  for (size_t szPos = 0; szPos < len; szPos++) {
    btDCS -= pbtData[szPos];
  }

  if (btDCS != abtRxBuf[0]) {
    ERR ("%s", "Data checksum mismatch");
    pnd->iLastError = DEIO;
    return -1;
  }

  if (0x00 != abtRxBuf[1]) {
    ERR ("%s", "Frame postamble mismatch");
    pnd->iLastError = DEIO;
    return -1;
  }
  ((struct pn53x_data*)(pnd->chip_data))->state = NORMAL;
  return len;
}

void
pn532_uart_ack (nfc_device_t * pnd)
{
  uart_send (((struct pn532_uart_data*)(pnd->driver_data))->port, ack_frame, sizeof (ack_frame));
}

bool
pn532_uart_check_communication (nfc_device_t *pnd)
{
  const byte_t abtMsg[] = { Diagnose, 0x00, 'l', 'i', 'b', 'n', 'f', 'c' };
  if (!pn532_uart_send (pnd, abtMsg, sizeof (abtMsg)))
    return false;

  const byte_t abtExpectedRes[] = { 0x00, 'l', 'i', 'b', 'n', 'f', 'c' };

  byte_t abtRes[sizeof(abtExpectedRes)];
  int res;
  if ((res = pn532_uart_receive (pnd, abtRes, sizeof(abtRes))) < 0)
    return false;

  return ((sizeof(abtRes) == res) && (0 == memcmp (abtRes, abtExpectedRes, sizeof(abtExpectedRes))));
}

const struct nfc_driver_t pn532_uart_driver = {
  .name       = PN532_UART_DRIVER_NAME,
  .probe      = pn532_uart_probe,
  .connect    = pn532_uart_connect,
  .send       = pn532_uart_send,
  .receive    = pn532_uart_receive,
  .disconnect = pn532_uart_disconnect,
  .strerror   = pn53x_strerror,
};