- // The command (reader -> tag) that we're working on receiving.
- uint8_t *receivedCmd = BigBuf_malloc(READER_TAG_BUFFER_SIZE);
- // The response (tag -> reader) that we're working on receiving.
- uint8_t *receivedResponse = BigBuf_malloc(TAG_READER_BUFFER_SIZE);
-
- // As we receive stuff, we copy it from receivedCmd or receivedResponse
- // into trace, along with its length and other annotations.
- uint8_t *trace = BigBuf_get_addr();
- traceLen = 0;
-
- // The DMA buffer, used to stream samples from the FPGA.
- uint8_t *dmaBuf = BigBuf_malloc(DEMOD_DMA_BUFFER_SIZE);
- int lastRxCounter;
- uint8_t *upTo;
- int ci, cq;
- int maxBehindBy = 0;
-
- // Count of samples received so far, so that we can include timing
- // information in the trace buffer.
- int samples = 0;
-
- // Initialize the trace buffer
- memset(trace, 0x44, BigBuf_max_traceLen());
-
- // Set up the demodulator for tag -> reader responses.
- Demod.output = receivedResponse;
- Demod.len = 0;
- Demod.state = DEMOD_UNSYNCD;
-
- // And the reader -> tag commands
- memset(&Uart, 0, sizeof(Uart));
- Uart.output = receivedCmd;
- Uart.byteCntMax = 100;
- Uart.state = STATE_UNSYNCD;
-
- // Print some debug information about the buffer sizes
- Dbprintf("Snooping buffers initialized:");
- Dbprintf(" Trace: %i bytes", BigBuf_max_traceLen());
- Dbprintf(" Reader -> tag: %i bytes", READER_TAG_BUFFER_SIZE);
- Dbprintf(" tag -> Reader: %i bytes", TAG_READER_BUFFER_SIZE);
- Dbprintf(" DMA: %i bytes", DEMOD_DMA_BUFFER_SIZE);
-
- // And put the FPGA in the appropriate mode
- // Signal field is off with the appropriate LED
- LED_D_OFF();
- FpgaWriteConfWord(
- FPGA_MAJOR_MODE_HF_READER_RX_XCORR | FPGA_HF_READER_RX_XCORR_848_KHZ |
- FPGA_HF_READER_RX_XCORR_SNOOP);
- SetAdcMuxFor(GPIO_MUXSEL_HIPKD);
-
- // Setup for the DMA.
- FpgaSetupSsc();
- upTo = dmaBuf;
- lastRxCounter = DEMOD_DMA_BUFFER_SIZE;
- FpgaSetupSscDma((uint8_t *)dmaBuf, DEMOD_DMA_BUFFER_SIZE);
-
- LED_A_ON();
-
- // And now we loop, receiving samples.
- for(;;) {
- int behindBy = (lastRxCounter - AT91C_BASE_PDC_SSC->PDC_RCR) &
- (DEMOD_DMA_BUFFER_SIZE-1);
- if(behindBy > maxBehindBy) {
- maxBehindBy = behindBy;
- if(behindBy > (9*DEMOD_DMA_BUFFER_SIZE/10)) { // TODO: understand whether we can increase/decrease as we want or not?
- Dbprintf("blew circular buffer! behindBy=0x%x", behindBy);
- goto done;
- }
- }
- if(behindBy < 2) continue;
-
- ci = upTo[0];
- cq = upTo[1];
- upTo += 2;
- lastRxCounter -= 2;
- if(upTo - dmaBuf > DEMOD_DMA_BUFFER_SIZE) {
- upTo -= DEMOD_DMA_BUFFER_SIZE;
- lastRxCounter += DEMOD_DMA_BUFFER_SIZE;
- AT91C_BASE_PDC_SSC->PDC_RNPR = (uint32_t) upTo;
- AT91C_BASE_PDC_SSC->PDC_RNCR = DEMOD_DMA_BUFFER_SIZE;
- }
-
- samples += 2;
-
-#define HANDLE_BIT_IF_BODY \
- if(triggered) { \
- trace[traceLen++] = ((samples >> 0) & 0xff); \
- trace[traceLen++] = ((samples >> 8) & 0xff); \
- trace[traceLen++] = ((samples >> 16) & 0xff); \
- trace[traceLen++] = ((samples >> 24) & 0xff); \
- trace[traceLen++] = 0; \
- trace[traceLen++] = 0; \
- trace[traceLen++] = 0; \
- trace[traceLen++] = 0; \
- trace[traceLen++] = Uart.byteCnt; \
- memcpy(trace+traceLen, receivedCmd, Uart.byteCnt); \
- traceLen += Uart.byteCnt; \
- if(traceLen > 1000) break; \
- } \
- /* And ready to receive another command. */ \
- memset(&Uart, 0, sizeof(Uart)); \
- Uart.output = receivedCmd; \
- Uart.byteCntMax = 100; \
- Uart.state = STATE_UNSYNCD; \
- /* And also reset the demod code, which might have been */ \
- /* false-triggered by the commands from the reader. */ \
- memset(&Demod, 0, sizeof(Demod)); \
- Demod.output = receivedResponse; \
- Demod.state = DEMOD_UNSYNCD; \
-
- if(Handle14443UartBit(ci & 1)) {
- HANDLE_BIT_IF_BODY
- }
- if(Handle14443UartBit(cq & 1)) {
- HANDLE_BIT_IF_BODY
- }
-
- if(Handle14443SamplesDemod(ci, cq)) {
- // timestamp, as a count of samples
- trace[traceLen++] = ((samples >> 0) & 0xff);
- trace[traceLen++] = ((samples >> 8) & 0xff);
- trace[traceLen++] = ((samples >> 16) & 0xff);
- trace[traceLen++] = 0x80 | ((samples >> 24) & 0xff);
- // correlation metric (~signal strength estimate)
- if(Demod.metricN != 0) {
- Demod.metric /= Demod.metricN;
- }
- trace[traceLen++] = ((Demod.metric >> 0) & 0xff);
- trace[traceLen++] = ((Demod.metric >> 8) & 0xff);
- trace[traceLen++] = ((Demod.metric >> 16) & 0xff);
- trace[traceLen++] = ((Demod.metric >> 24) & 0xff);
- // length
- trace[traceLen++] = Demod.len;
- memcpy(trace+traceLen, receivedResponse, Demod.len);
- traceLen += Demod.len;
- if(traceLen > BigBuf_max_traceLen()) {
- DbpString("Reached trace limit");
- goto done;
- }
projects / proxmark3-svn / blobdiff