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/***************************************************************
*
* OpenPICC - ISO 14443 Layer 2 Type A PICC transceiver code
* Manages receiving, sending and parts of framing
*
* This does not fully implement layer 2 in that it won't
* automatically call the Miller decoder or Manchester encoder
* for you. Instead you'll be given ssc rx buffer pointers and
* are expected to hand in ssc tx buffer pointers. You've got
* to call iso14443a_manchester and iso14443a_miller yourself.
* The reason is that this makes it possible for the layer 3
* implementation to work on raw samples without en/de-coding
* time to enable fast responses during anticollision.
*
* Copyright 2008 Henryk Plötz <henryk@ploetzli.ch>
*
***************************************************************
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 <FreeRTOS.h>
#include <board.h>
#include <task.h>
#include <errno.h>
#include "openpicc.h"
#include "iso14443_layer2a.h"
#include "ssc.h"
#include "pll.h"
#include "tc_fdt.h"
#include "tc_cdiv.h"
#include "tc_cdiv_sync.h"
#include "load_modulation.h"
#include "pio_irq.h"
#include "usb_print.h"
#define PRINT_DEBUG 0
static u_int8_t fast_receive;
static ssc_handle_t *ssc;
#ifdef FOUR_TIMES_OVERSAMPLING
#define RX_DIVIDER 32
#else
#define RX_DIVIDER 64
#endif
int iso14443_receive(iso14443_receive_callback_t callback, ssc_dma_rx_buffer_t **buffer, unsigned int timeout)
{
(void)callback; (void)timeout;
ssc_dma_rx_buffer_t* _buffer = NULL;
int len;
if(ssc_recv(ssc, &_buffer, timeout) == 0) {
if(_buffer == NULL) {
/* Can this happen? */
return -ETIMEDOUT;
}
portENTER_CRITICAL();
_buffer->state = PROCESSING;
portEXIT_CRITICAL();
len = _buffer->len_transfers;
if(buffer != NULL) *buffer = _buffer;
else {
portENTER_CRITICAL();
_buffer->state = FREE;
portEXIT_CRITICAL();
}
return len;
}
if(AT91F_PIO_IsInputSet(AT91C_BASE_PIOA, OPENPICC_PIO_FRAME)) tc_cdiv_sync_reset();
return -ETIMEDOUT;
}
int iso14443_wait_for_carrier(unsigned int timeout)
{
(void)timeout;
return 0;
}
u_int8_t iso14443_set_fast_receive(u_int8_t enable_fast_receive)
{
u_int8_t old_value = fast_receive;
fast_receive = enable_fast_receive;
return old_value;
}
u_int8_t iso14443_get_fast_receive(void)
{
return fast_receive;
}
static void iso14443_ssc_callback(ssc_callback_reason reason, void *data)
{
(void) data;
if(reason == CALLBACK_RX_FRAME_BEGIN) {
/* Busy loop for the frame end */
int *end_asserted = data, i=0;
for(i=0; i<96000; i++)
if(*AT91C_TC2_CV > 2*128) { // FIXME magic number
*end_asserted = 1;
if(PRINT_DEBUG) usb_print_string_f("^", 0); // DEBUG OUTPUT
break;
}
return;
}
if( reason == CALLBACK_RX_FRAME_ENDED || reason == CALLBACK_RX_STARTED ) {
tc_fdt_set(0xff00);
tc_cdiv_set_divider(RX_DIVIDER);
tc_cdiv_sync_reset();
}
}
static void iso14443_rx_FRAME_cb(u_int32_t pio)
{
(void)pio;
if(PRINT_DEBUG) usb_print_string_f("°", 0); // DEBUG OUTPUT
if(AT91F_PIO_IsInputSet(AT91C_BASE_PIOA, OPENPICC_PIO_FRAME))
ssc_frame_started();
}
int iso14443_layer2a_init(u_int8_t enable_fast_receive)
{
pll_init();
tc_cdiv_init();
tc_fdt_init();
load_mod_init();
iso14443_set_fast_receive(enable_fast_receive);
pio_irq_init_once();
if(pio_irq_register(OPENPICC_PIO_FRAME, &iso14443_rx_FRAME_cb) >= 0) {
if(PRINT_DEBUG) usb_print_string("FRAME irq registered\n\r"); // DEBUG OUTPUT
}
ssc = ssc_open(1, 0, SSC_MODE_14443A, iso14443_ssc_callback);
if(ssc == NULL)
return -EIO;
// FIXME should be 3 for production, when tx code is implemented
load_mod_level(0);
return 0;
}
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