Merge pull request #367 from oliv3r/respect_pn532_i2c_timing
Respect pn532 i2c timing
This commit is contained in:
Romuald Conty
GitHub
commit
b2a9cce037
2 changed files with 114 additions and 38 deletions
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@ -81,32 +81,38 @@
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#define TgGetTargetStatus 0x8A
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/** @note PN53x's normal frame:
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* See the PN532 (firmware) user manual, section 6.2.1.1: Normal information
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* frame, figure 13. Normal information frame, page 28 rev. 02 - 2007-11-07.
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*
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* .-- Start
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* | .-- Packet length
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* | | .-- Length checksum
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* | | | .-- Direction (D4 Host to PN, D5 PN to Host)
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* | | | | .-- Code
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* | | | | | .-- Packet checksum
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* | | | | | | .-- Postamble
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* V | | | | | |
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* ----- V V V V V V
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* 00 FF 02 FE D4 02 2A 00
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* .-- Preamble
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* | .-- Start
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* | | .-- Packet length
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* | | | .-- Length checksum
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* | | | | .-- Direction (D4 Host to PN, D5 PN to Host)
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* | | | | | .-- Code
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* | | | | | | .-- Packet checksum
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* | | | | | | | .-- Postamble
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* | V | | | | | |
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* V ----- V V V V V V
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* 00 00 FF 02 FE D4 02 2A 00
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*/
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/** @note PN53x's extended frame:
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* See the PN532 (firmware) user manual, section 6.2.1.2: Extended information
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* frame, figure 14. Normal information frame, page 29 rev. 02 - 2007-11-07.
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*
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* .-- Start
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* | .-- Fixed to FF to enable extended frame
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* | | .-- Packet length
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* | | | .-- Length checksum
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* | | | | .-- Direction (D4 Host to PN, D5 PN to Host)
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* | | | | | .-- Code
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* | | | | | | .-- Packet checksum
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* | | | | | | | .-- Postamble
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* V V V | | | | |
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* ----- ----- ----- V V V V V
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* 00 FF FF FF 00 02 FE D4 02 2A 00
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* .-- Preamble
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* | .-- Start
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* | | .-- Fixed to FF to enable extended frame
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* | | | .-- Packet length
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* | | | | .-- Length checksum
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* | | | | | .-- Direction (D4 Host to PN, D5 PN to Host)
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* | | | | | | .-- Code
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* | | | | | | | .-- Packet checksum
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* | | | | | | | | .-- Postamble
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* | V V V | | | | |
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* V ----- ----- ----- V V V V V
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* 00 00 FF FF FF 00 02 FE D4 02 2A 00
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*/
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/**
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@ -59,6 +59,13 @@
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// I2C address of the PN532 chip.
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#define PN532_I2C_ADDR 0x24
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/*
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* When sending lots of data, the pn532 occasionally fails to respond in time.
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* Since it happens so rarely, lets try to fix it by re-sending the data. This
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* define allows for fine tuning the number of retries.
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*/
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#define PN532_SEND_RETRIES 3
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// Internal data structs
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const struct pn53x_io pn532_i2c_io;
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@ -67,13 +74,9 @@ struct pn532_i2c_data {
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volatile bool abort_flag;
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};
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/* Delay for the loop waiting for READY frame (in ms) */
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#define PN532_RDY_LOOP_DELAY 90
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const struct timespec rdyDelay = {
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.tv_sec = 0,
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.tv_nsec = PN532_RDY_LOOP_DELAY * 1000 * 1000
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};
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/* preamble and start bytes, see pn532-internal.h for details */
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const uint8_t pn53x_preamble_and_start[] = { 0x00, 0x00, 0xff };
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#define PN53X_PREAMBLE_AND_START_LEN (sizeof(pn53x_preamble_and_start) / sizeof(pn53x_preamble_and_start[0]))
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/* Private Functions Prototypes */
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@ -96,6 +99,70 @@ static size_t pn532_i2c_scan(const nfc_context *context, nfc_connstring connstri
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#define DRIVER_DATA(pnd) ((struct pn532_i2c_data*)(pnd->driver_data))
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/*
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* Bus free time (in ms) between a STOP condition and START condition. See
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* tBuf in the PN532 data sheet, section 12.25: Timing for the I2C interface,
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* table 320. I2C timing specification, page 211, rev. 3.2 - 2007-12-07.
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*/
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#define PN532_BUS_FREE_TIME 1.3
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static struct timespec __transaction_stop;
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/**
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* @brief Wrapper around i2c_read to ensure proper timing by respecting the
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* minimal free bus time between a STOP condition and a START condition.
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*
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* @note This is not thread safe, but since libnfc is single threaded
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* this should be okay.
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*
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* @param id I2C device
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* @param buf pointer on buffer used to store data
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* @param len length of the buffer
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* @return length (in bytes) of read data, or driver error code (negative value)
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*/
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static ssize_t pn532_i2c_read(const i2c_device id,
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uint8_t *buf, const size_t len)
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{
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struct timespec transaction_start, bus_free_time = { 0 };
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ssize_t ret;
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clock_gettime(CLOCK_MONOTONIC, &transaction_start);
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bus_free_time.tv_nsec = (PN532_BUS_FREE_TIME * 1000 * 1000) -
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(transaction_start.tv_nsec - __transaction_stop.tv_nsec);
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nanosleep(&bus_free_time, NULL);
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ret = i2c_read(id, buf, len);
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clock_gettime(CLOCK_MONOTONIC, &__transaction_stop);
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return ret;
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}
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/**
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* @brief Wrapper around i2c_write to ensure proper timing by respecting the
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* minimal free bus time between a STOP condition and a START condition.
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*
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* @note This is not thread safe, but since libnfc is single threaded
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* this should be okay.
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*
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* @param id I2C device
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* @param buf pointer on buffer containing data
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* @param len length of the buffer
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* @return NFC_SUCCESS on success, otherwise driver error code
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*/
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static ssize_t pn532_i2c_write(const i2c_device id,
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const uint8_t *buf, const size_t len)
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{
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struct timespec transaction_start, bus_free_time = { 0 };
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ssize_t ret;
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clock_gettime(CLOCK_MONOTONIC, &transaction_start);
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bus_free_time.tv_nsec = (PN532_BUS_FREE_TIME * 1000 * 1000) -
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(transaction_start.tv_nsec - __transaction_stop.tv_nsec);
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nanosleep(&bus_free_time, NULL);
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ret = i2c_write(id, buf, len);
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clock_gettime(CLOCK_MONOTONIC, &__transaction_stop);
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return ret;
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}
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/**
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* @brief Scan all available I2C buses to find PN532 devices.
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*
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@ -308,6 +375,7 @@ static int
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pn532_i2c_send(nfc_device *pnd, const uint8_t *pbtData, const size_t szData, int timeout)
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{
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int res = 0;
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uint8_t retries;
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// Discard any existing data ?
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@ -334,15 +402,22 @@ pn532_i2c_send(nfc_device *pnd, const uint8_t *pbtData, const size_t szData, int
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break;
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};
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uint8_t abtFrame[PN532_BUFFER_LEN] = { 0x00, 0x00, 0xff }; // Every packet must start with "00 00 ff"
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uint8_t abtFrame[PN532_BUFFER_LEN];
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size_t szFrame = 0;
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memcpy(abtFrame, pn53x_preamble_and_start, PN53X_PREAMBLE_AND_START_LEN); // Every packet must start with the preamble and start bytes.
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if ((res = pn53x_build_frame(abtFrame, &szFrame, pbtData, szData)) < 0) {
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pnd->last_error = res;
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return pnd->last_error;
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}
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res = i2c_write(DRIVER_DATA(pnd)->dev, abtFrame, szFrame);
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for (retries = PN532_SEND_RETRIES; retries > 0; retries--) {
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res = pn532_i2c_write(DRIVER_DATA(pnd)->dev, abtFrame, szFrame);
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if (res >= 0)
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break;
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log_put(LOG_GROUP, LOG_CATEGORY, NFC_LOG_PRIORITY_ERROR, "Failed to transmit data. Retries left: %d.", retries - 1);
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}
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if (res < 0) {
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log_put(LOG_GROUP, LOG_CATEGORY, NFC_LOG_PRIORITY_ERROR, "%s", "Unable to transmit data. (TX)");
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@ -400,10 +475,7 @@ pn532_i2c_wait_rdyframe(nfc_device *pnd, uint8_t *pbtData, const size_t szDataLe
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}
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do {
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// Wait a little bit before reading
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nanosleep(&rdyDelay, (struct timespec *) NULL);
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int recCount = i2c_read(DRIVER_DATA(pnd)->dev, i2cRx, szDataLen + 1);
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int recCount = pn532_i2c_read(DRIVER_DATA(pnd)->dev, i2cRx, szDataLen + 1);
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if (DRIVER_DATA(pnd)->abort_flag) {
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// Reset abort flag
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@ -477,9 +549,7 @@ pn532_i2c_receive(nfc_device *pnd, uint8_t *pbtData, const size_t szDataLen, int
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goto error;
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}
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const uint8_t pn53x_preamble[3] = { 0x00, 0x00, 0xff };
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if (0 != (memcmp(frameBuf, pn53x_preamble, 3))) {
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if (0 != (memcmp(frameBuf, pn53x_preamble_and_start, PN53X_PREAMBLE_AND_START_LEN))) {
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log_put(LOG_GROUP, LOG_CATEGORY, NFC_LOG_PRIORITY_ERROR, "%s", "Frame preamble+start code mismatch");
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pnd->last_error = NFC_EIO;
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goto error;
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@ -572,7 +642,7 @@ error:
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int
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pn532_i2c_ack(nfc_device *pnd)
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{
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return i2c_write(DRIVER_DATA(pnd)->dev, pn53x_ack_frame, sizeof(pn53x_ack_frame));
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return pn532_i2c_write(DRIVER_DATA(pnd)->dev, pn53x_ack_frame, sizeof(pn53x_ack_frame));
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}
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/**
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