From 3ee3c4a649545d1f132bca61cc7484f0d5c92638 Mon Sep 17 00:00:00 2001 From: henryk Date: Wed, 5 Mar 2008 01:59:58 +0000 Subject: Copy over the relevant changes from the sniffonly branch pending integration git-svn-id: https://svn.openpcd.org:2342/trunk@442 6dc7ffe9-61d6-0310-9af1-9938baff3ed1 --- openpicc/application/tc_sniffer.c | 143 ++++++++++++++++++++++++++++++++++++++ 1 file changed, 143 insertions(+) create mode 100644 openpicc/application/tc_sniffer.c (limited to 'openpicc/application/tc_sniffer.c') diff --git a/openpicc/application/tc_sniffer.c b/openpicc/application/tc_sniffer.c new file mode 100644 index 0000000..abf04c0 --- /dev/null +++ b/openpicc/application/tc_sniffer.c @@ -0,0 +1,143 @@ +/*************************************************************** + * + * OpenPICC - T/C based dumb sniffer + * + * TC2 will reset its value on each falling edge of SSC_DATA, we + * will have the FIQ store the TC2 value on each rising edge of + * SSC_DATA. This will give us a count of carrier cycles between + * modulation pauses which should be enough information to decode + * the modified miller encoding. + * + * Copyright 2008 Henryk Plötz + * + *************************************************************** + + This program is free software; you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation; version 2. + + 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 General Public License along + with this program; if not, write to the Free Software Foundation, Inc., + 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. + +*/ + +#include +#include +#include +#include + +#include + +#include "tc_sniffer.h" +#include "load_modulation.h" +#include "pll.h" +#include "tc_fdt.h" +#include "usb_print.h" +#include "cmd.h" +#include "pio_irq.h" + +/* Problem: We want to receive data from the FIQ without locking (the FIQ must not be blocked ever) + * Strategy: Double buffering. + */ + +#define BUFSIZE 1024 +#define WAIT_TICKS (20*portTICK_RATE_MS) +typedef struct { + u_int32_t count; + u_int32_t data[BUFSIZE]; +} fiq_buffer_t; +fiq_buffer_t fiq_buffers[2]; + +fiq_buffer_t *tc_sniffer_next_buffer_for_fiq = 0; + +portBASE_TYPE currently_sniffing = 0; +enum { NONE, REQUEST_START, REQUEST_STOP } request_change = NONE; + +#define MIN(a, b) ((a)>(b)?(b):(a)) +void flush_buffer(fiq_buffer_t *buffer) +{ + /* Write all data from the given buffer out, then zero the count */ + if(buffer->count > 0) { + vUSBSendBuffer_blocking((unsigned char*)(&(buffer->data[0])), 0, MIN(buffer->count,BUFSIZE)*4, WAIT_TICKS); + if(buffer->count >= BUFSIZE) + vUSBSendBuffer_blocking((unsigned char*)"////", 0, 4, WAIT_TICKS); + else + vUSBSendBuffer_blocking((unsigned char*)"____", 0, 4, WAIT_TICKS); + buffer->count = 0; + } +} + +void start_stop_sniffing(void) +{ + if(currently_sniffing) + request_change = REQUEST_STOP; + else + request_change = REQUEST_START; +} + +void tc_sniffer (void *pvParameters) +{ + (void)pvParameters; + + /* Disable load modulation circuitry + * (Must be done explicitly, because the default state is pull-up high, leading + * to a constant modulation output which prevents reception. I've been bitten by + * this more than once.) + */ + load_mod_init(); + load_mod_level(0); + + pll_init(); + pll_inhibit(0); + + tc_fdt_init(); + + memset(fiq_buffers, 0, sizeof(fiq_buffers)); + + /* Wait for the USB and CMD threads to start up */ + vTaskDelay(1000 * portTICK_RATE_MS); + + // The change interrupt is going to be handled by the FIQ + AT91F_PIO_CfgInput(AT91C_BASE_PIOA, OPENPICC_SSC_DATA); + pio_irq_enable(OPENPICC_SSC_DATA); + + int current = 0; + while(1) { + /* Main loop of the sniffer */ + + if(currently_sniffing) { + int next = (current+1)%(sizeof(fiq_buffers)/sizeof(fiq_buffers[0])); + flush_buffer( &fiq_buffers[next] ); + /* The buffer designated by next is now empty, give it to the fiq, + * we'll just guess that this write is atomic */ + tc_sniffer_next_buffer_for_fiq = &fiq_buffers[current=next]; + + if(request_change == REQUEST_STOP) { + currently_sniffing = 0; + request_change = NONE; + + tc_sniffer_next_buffer_for_fiq = 0; + memset(fiq_buffers, 0, sizeof(fiq_buffers)); + current = 0; + vUSBSendBuffer_blocking((unsigned char *)"----", 0, 4, WAIT_TICKS); + usb_print_set_force_silence(0); + } else vTaskDelay(2* portTICK_RATE_MS); + } else { + // Do nothing, wait longer + + if(request_change == REQUEST_START) { + // Prevent usb_print code from barging in + usb_print_set_force_silence(1); + vUSBSendBuffer_blocking((unsigned char *)"----", 0, 4, WAIT_TICKS); + currently_sniffing = 1; + request_change = NONE; + } else vTaskDelay(100 * portTICK_RATE_MS); + } + } +} -- cgit v1.2.3