Some optimisations in initialisation of registers

examples/nfc-list.c

@@ -127,11 +127,11 @@ main (int argc, const char *argv[])
 
     printf ("Connected to NFC device: %s\n", pnd->acName);
 
+    nfc_modulation_t nm;
+
+    nm.nmt = NMT_ISO14443A;
+    nm.nbr = NBR_106;
     // List ISO14443A targets
-    nfc_modulation_t nm = {
-      .nmt = NMT_ISO14443A,
-      .nbr = NBR_106,
-    };
     if (nfc_initiator_list_passive_targets (pnd, nm, ant, MAX_TARGET_COUNT, &szTargetFound)) {
       size_t  n;
       if (verbose || (szTargetFound > 0)) {

include/nfc/nfc-types.h

@@ -49,11 +49,12 @@ typedef struct {
   char    acName[DEVICE_NAME_LENGTH];
 /** Is the crc automaticly added, checked and removed from the frames */
   bool    bCrc;
-/** Does the PN53x chip handles parity bits, all parities are handled as data */
+/** Does the chip handle parity bits, all parities are handled as data */
   bool    bPar;
-/** Should the PN53x chip handle frames encapsulation and chaining */
+/** Should the chip handle frames encapsulation and chaining */
   bool    bEasyFraming;
-/** Should the PN53x chip switch automatically in ISO14443-4 when ISO14443 */
+/** Should the chip switch automatically activate ISO14443-4 when
+    selecting tags supporting it? */
   bool    bAutoIso14443_4;
 /** Supported modulation encoded in a byte */
   byte_t  btSupportByte;

libnfc/chips/pn53x-internal.h

@@ -292,12 +292,11 @@ typedef struct {
 
 #define PN53X_SFR_P3 0xFFB0
 
-#define PN53X_SFR_P3CFGA 0xFFFC 
+#define PN53X_SFR_P3CFGA 0xFFFC
-#define PN53X_SFR_P3CFGB 0xFFFD 
+#define PN53X_SFR_P3CFGB 0xFFFD
-#define PN53X_SFR_P3 0xFFB0 
+#define PN53X_SFR_P7CFGA 0xFFF4
-#define PN53X_SFR_P7CFGA 0xFFF4 
+#define PN53X_SFR_P7CFGB 0xFFF5
-#define PN53X_SFR_P7CFGB 0xFFF5 
+#define PN53X_SFR_P7 0xFFF7
-#define PN53X_SFR_P7 0xFFF7 
 
 
 #ifdef DEBUG

libnfc/chips/pn53x.c

@@ -69,10 +69,10 @@ pn53x_init(nfc_device_t * pnd)
     return false;
   }
 
-  // CRC handling is enabled by default
+  // CRC handling should be enabled by default as declared in nfc_device_new
-  pnd->bCrc = true;
+  // which is the case by default for pn53x, so nothing to do here
-  // Parity handling is enabled by default
+  // Parity handling should be enabled by default as declared in nfc_device_new
-  pnd->bPar = true;
+  // which is the case by default for pn53x, so nothing to do here
 
   // We can't read these parameters, so we set a default config by using the SetParameters wrapper
   // Note: pn53x_SetParameters() will save the sent value in pnd->ui8Parameters cache
@@ -512,11 +512,11 @@ pn53x_writeback_register (nfc_device_t * pnd)
   BUFFER_INIT (abtReadRegisterCmd, PN53x_EXTENDED_FRAME__DATA_MAX_LEN);
   BUFFER_APPEND (abtReadRegisterCmd, ReadRegister);
 
-  // First step, it looks for registers to be readed before applying the requested mask
+  // First step, it looks for registers to be read before applying the requested mask
   CHIP_DATA (pnd)->wb_trigged = false;
   for (size_t n = 0; n < PN53X_CACHE_REGISTER_SIZE; n++) {
     if ((CHIP_DATA (pnd)->wb_mask[n]) && (CHIP_DATA (pnd)->wb_mask[n] != 0xff)) {
-      // This register needs to be readed: mask is present but does not cover full data width (ie. mask != 0xff)
+      // This register needs to be read: mask is present but does not cover full data width (ie. mask != 0xff)
       const uint16_t pn53x_register_address = PN53X_CACHE_REGISTER_MIN_ADDRESS + n;
       BUFFER_APPEND (abtReadRegisterCmd, pn53x_register_address  >> 8);
       BUFFER_APPEND (abtReadRegisterCmd, pn53x_register_address & 0xff);
@@ -620,10 +620,13 @@ bool
 pn53x_configure (nfc_device_t * pnd, const nfc_device_option_t ndo, const bool bEnable)
 {
   byte_t  btValue;
-
   switch (ndo) {
     case NDO_HANDLE_CRC:
       // Enable or disable automatic receiving/sending of CRC bytes
+      if (bEnable == pnd->bCrc) {
+        // Nothing to do
+        return true;
+      }
       // TX and RX are both represented by the symbol 0x80
       btValue = (bEnable) ? 0x80 : 0x00;
       if (!pn53x_write_register (pnd, PN53X_REG_CIU_TxMode, SYMBOL_TX_CRC_ENABLE, btValue))
@@ -635,6 +638,9 @@ pn53x_configure (nfc_device_t * pnd, const nfc_device_option_t ndo, const bool b
 
     case NDO_HANDLE_PARITY:
       // Handle parity bit by PN53X chip or parse it as data bit
+      if (bEnable == pnd->bPar)
+        // Nothing to do
+        return true;
       btValue = (bEnable) ? 0x00 : SYMBOL_PARITY_DISABLE;
       if (!pn53x_write_register (pnd, PN53X_REG_CIU_ManualRCV, SYMBOL_PARITY_DISABLE, btValue))
         return false;
@@ -691,7 +697,9 @@ pn53x_configure (nfc_device_t * pnd, const nfc_device_option_t ndo, const bool b
       break;
 
     case NDO_AUTO_ISO14443_4:
-      // TODO Cache activated/disactivated options
+      if (bEnable == pnd->bAutoIso14443_4)
+        // Nothing to do
+        return true;
       pnd->bAutoIso14443_4 = bEnable;
       return pn53x_set_parameters (pnd, PARAM_AUTO_RATS, bEnable);
       break;

libnfc/nfc.c

@@ -74,18 +74,8 @@ const struct nfc_driver_t *nfc_drivers[] = {
  * When it has successfully claimed a NFC device, memory is allocated to save the device information. It will return a pointer to a \a nfc_device_t struct.
  * This pointer should be supplied by every next functions of libnfc that should perform an action with this device.
  *
- * @note During this function, the device will be configured with default initiator options, cf nfc_initiator_init:
+ * @note Depending on the desired operation mode, the device needs to be configured
- * - Crc is handled by the device (NDO_HANDLE_CRC = true)
+ * by using nfc_initiator_init() or nfc_target_init(), optionally followed by manual tuning of the parameters if the default parameters are not suiting your goals.
- * - Parity is handled the device (NDO_HANDLE_PARITY = true)
- * - Cryto1 cipher is disabled (NDO_ACTIVATE_CRYPTO1 = false)
- * - Easy framing is enabled (NDO_EASY_FRAMING = true)
- * - Auto-switching in ISO14443-4 mode is enabled (NDO_AUTO_ISO14443_4 = true)
- * - Invalid frames are not accepted (NDO_ACCEPT_INVALID_FRAMES = false)
- * - Multiple frames are not accepted (NDO_ACCEPT_MULTIPLE_FRAMES = false)
- * - 14443-A mode is activated (NDO_FORCE_ISO14443_A = true)
- * - speed is set to 106 kbps (NDO_FORCE_SPEED_106 = true)
- * - Let the device try forever to find a target (NDO_INFINITE_SELECT = true)
- * - RF field is shortly dropped (if it was enabled) then activated again
  */
 nfc_device_t *
 nfc_connect (nfc_device_desc_t * pndd)
@@ -113,11 +103,6 @@ nfc_connect (nfc_device_desc_t * pndd)
     // Test if the connection was successful
     if (pnd != NULL) {
       DBG ("[%s] has been claimed.", pnd->acName);
-
-      // Set default configuration options
-      if (!nfc_initiator_init(pnd))
-        return NULL;
-
       return pnd;
     } else {
       DBG ("No device found using driver: %s", ndr->name);
@@ -230,6 +215,17 @@ nfc_configure (nfc_device_t * pnd, const nfc_device_option_t ndo, const bool bEn
  * The NFC device is configured to function as RFID reader.
  * After initialization it can be used to communicate to passive RFID tags and active NFC devices.
  * The reader will act as initiator to communicate peer 2 peer (NFCIP) to other active NFC devices.
+ * - Crc is handled by the device (NDO_HANDLE_CRC = true)
+ * - Parity is handled the device (NDO_HANDLE_PARITY = true)
+ * - Cryto1 cipher is disabled (NDO_ACTIVATE_CRYPTO1 = false)
+ * - Easy framing is enabled (NDO_EASY_FRAMING = true)
+ * - Auto-switching in ISO14443-4 mode is enabled (NDO_AUTO_ISO14443_4 = true)
+ * - Invalid frames are not accepted (NDO_ACCEPT_INVALID_FRAMES = false)
+ * - Multiple frames are not accepted (NDO_ACCEPT_MULTIPLE_FRAMES = false)
+ * - 14443-A mode is activated (NDO_FORCE_ISO14443_A = true)
+ * - speed is set to 106 kbps (NDO_FORCE_SPEED_106 = true)
+ * - Let the device try forever to find a target (NDO_INFINITE_SELECT = true)
+ * - RF field is shortly dropped (if it was enabled) then activated again
  */
 bool
 nfc_initiator_init (nfc_device_t * pnd)
@@ -237,6 +233,15 @@ nfc_initiator_init (nfc_device_t * pnd)
   // Drop the field for a while
   if (!nfc_configure (pnd, NDO_ACTIVATE_FIELD, false))
     return false;
+  // Enable field so more power consuming cards can power themselves up
+  if (!nfc_configure (pnd, NDO_ACTIVATE_FIELD, true))
+    return false;
+  // Let the device try forever to find a target/tag
+  if (!nfc_configure (pnd, NDO_INFINITE_SELECT, true))
+    return false;
+  // Activate auto ISO14443-4 switching by default
+  if (!nfc_configure (pnd, NDO_AUTO_ISO14443_4, true))
+    return false;
   // Force 14443-A mode
   if (!nfc_configure (pnd, NDO_FORCE_ISO14443_A, true))
     return false;
@@ -257,18 +262,9 @@ nfc_initiator_init (nfc_device_t * pnd)
   // Activate "easy framing" feature by default
   if (!nfc_configure (pnd, NDO_EASY_FRAMING, true))
     return false;
-  // Activate auto ISO14443-4 switching by default
-  if (!nfc_configure (pnd, NDO_AUTO_ISO14443_4, true))
-    return false;
   // Deactivate the CRYPTO1 cipher, it may could cause problems when still active
   if (!nfc_configure (pnd, NDO_ACTIVATE_CRYPTO1, false))
     return false;
-  // Let the device try forever to find a target/tag
-  if (!nfc_configure (pnd, NDO_INFINITE_SELECT, true))
-    return false;
-  // Enable field so more power consuming cards can power themselves up
-  if (!nfc_configure (pnd, NDO_ACTIVATE_FIELD, true))
-    return false;
 
   HAL (initiator_init, pnd);
 }
@@ -608,8 +604,15 @@ nfc_initiator_transceive_bits_timed (nfc_device_t * pnd, const byte_t * pbtTx, c
  * @param[out] pbtRx Rx buffer pointer
  * @param[out] pszRx received bytes count
  *
- * This function initialize NFC device in \e target mode in order to emulate a
+ * This function initializes NFC device in \e target mode in order to emulate a
  * tag using the specified \a nfc_target_mode_t.
+ * - Crc is handled by the device (NDO_HANDLE_CRC = true)
+ * - Parity is handled the device (NDO_HANDLE_PARITY = true)
+ * - Cryto1 cipher is disabled (NDO_ACTIVATE_CRYPTO1 = false)
+ * - Easy framing is disabled (NDO_EASY_FRAMING = false)
+ * - Invalid frames are not accepted (NDO_ACCEPT_INVALID_FRAMES = false)
+ * - Multiple frames are not accepted (NDO_ACCEPT_MULTIPLE_FRAMES = false)
+ * - RF field is dropped
  *
  * @warning Be aware that this function will wait (hang) until a command is
  * received that is not part of the anti-collision. The RATS command for