361 lines
8.9 KiB
C
361 lines
8.9 KiB
C
/*
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* Copyright (C) 1995 Advanced RISC Machines Limited. All rights reserved.
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*
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* This software may be freely used, copied, modified, and distributed
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* provided that the above copyright notice is preserved in all copies of the
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* software.
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*/
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/*-*-C-*-
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*
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* $Revision$
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* $Date$
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*
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*
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* Project: ANGEL
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*
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* Title: Character reception engine
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*/
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#include <stdarg.h> /* ANSI varargs support */
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#include "angel.h" /* Angel system definitions */
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#include "endian.h" /* Endian independant memory access macros */
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#include "crc.h" /* crc generation definitions and headers */
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#include "rxtx.h"
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#include "channels.h"
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#include "buffers.h"
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#ifdef TARGET
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# include "devdriv.h"
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#endif
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#include "logging.h"
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static re_status unexp_stx(struct re_state *rxstate);
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static re_status unexp_etx(struct re_state *rxstate);
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/* bitfield for the rx_engine state */
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typedef enum rx_state_flag{
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RST_STX,
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RST_TYP,
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RST_LEN,
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RST_DAT,
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RST_CRC,
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RST_ETX,
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RST_ESC = (0x1 << 0x3)
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} rx_state_flag;
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void Angel_RxEngineInit(const struct re_config *rxconfig,
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struct re_state *rxstate)
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{
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rxstate->rx_state = RST_STX;
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rxstate->field_c = 0;
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rxstate->index = 0;
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rxstate->crc = 0;
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rxstate->error = RE_OKAY;
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rxstate->config = rxconfig;
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}
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re_status Angel_RxEngine(unsigned char new_ch, struct data_packet *packet,
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struct re_state *rxstate)
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{
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/*
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* TODO: add the flow control bits in
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* Note: We test for the data field in a seperate case so we can
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* completely avoid entering the switch for most chars
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*/
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/* see if we're expecting a escaped char */
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if ((rxstate->rx_state & RST_ESC) == RST_ESC)
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{
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/* unescape the char and unset the flag*/
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new_ch &= ~serial_ESCAPE;
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#ifdef DO_TRACE
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__rt_trace("rxe-echar-%2x ", new_ch);
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#endif
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rxstate->rx_state &= ~RST_ESC;
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}
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else if ( (1 << new_ch) & rxstate->config->esc_set )
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{
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/* see if the incoming char is a special one */
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if (new_ch == rxstate->config->esc)
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{
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#ifdef DO_TRACE
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__rt_trace("rxe-esc ");
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#endif
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rxstate->rx_state |= RST_ESC;
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return RS_IN_PKT;
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}
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else
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{
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/*
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* must be a normal packet so do some unexpected etx/stx checking
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* we haven't been told to escape or received an escape so unless
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* we are expecting an stx or etx then we can take the unexpected
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* stx/etx trap
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*/
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if ((new_ch == (rxstate->config->stx)) && (rxstate->rx_state != RST_STX))
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return unexp_stx(rxstate);
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if ((new_ch == (rxstate->config->etx)) && (rxstate->rx_state != RST_ETX))
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return unexp_etx(rxstate);
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}
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}
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if (rxstate->rx_state == RST_DAT)
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{
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/*
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* do this to speed up the common case, no real penalty for
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* other cases
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*/
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#ifdef DO_TRACE
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__rt_trace("rxe-dat ");
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#endif
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rxstate->crc = crc32(&new_ch, 1, rxstate->crc);
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(packet->data)[rxstate->index++] = (unsigned int)new_ch & 0xff;
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if (rxstate->index == packet->len)
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rxstate->rx_state = RST_CRC;
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return RS_IN_PKT;
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}
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/*
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* Now that the common case is out of the way we can test for everything
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* else without worrying quite so much about the speed, changing the
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* order to len,crc,stx,etx,typ might gain a tiny bit of speed but lets
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* leave that for the moment
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*/
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switch (rxstate->rx_state)
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{
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case RST_STX:
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if (new_ch == rxstate->config->stx)
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{
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rxstate->rx_state = RST_TYP;
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rxstate->error = RE_OKAY;
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rxstate->crc = startCRC32;
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rxstate->index = 0;
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return RS_IN_PKT;
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}
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else
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{
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rxstate->error = RE_OKAY;
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return RS_WAIT_PKT;
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}
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case RST_TYP:
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packet->type = (DevChanID)new_ch;
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rxstate->rx_state = RST_LEN;
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rxstate->error = RE_OKAY;
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rxstate->field_c = 0; /* set up here for the length that follows */
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#ifdef DO_TRACE
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__rt_trace("rxe-type-%2x ", packet->type);
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#endif
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rxstate->crc = crc32(&new_ch, 1, rxstate->crc);
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return RS_IN_PKT;
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case RST_LEN:
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rxstate->crc = crc32(&new_ch, 1, rxstate->crc);
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if (rxstate->field_c++ == 0)
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{
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/* first length byte */
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packet->len = ((unsigned int)new_ch) << 8;
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return RS_IN_PKT;
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}
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else
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{
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/* got the whole legth */
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packet->len |= new_ch;
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#ifdef DO_TRACE
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__rt_trace("rxe-len-%4x\n", packet->len);
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#endif
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/* check that the length is ok */
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if (packet->len == 0)
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{
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/* empty pkt */
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rxstate->field_c = 0;
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rxstate->rx_state = RST_CRC;
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return RS_IN_PKT;
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}
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else
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{
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if (packet->data == NULL)
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{
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/* need to alloc the data buffer */
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if (!rxstate->config->ba_callback(
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packet, rxstate->config->ba_data)) {
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rxstate->rx_state = RST_STX;
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rxstate->error = RE_INTERNAL;
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return RS_BAD_PKT;
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}
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}
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if (packet->len > packet->buf_len)
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{
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/* pkt bigger than buffer */
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rxstate->field_c = 0;
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rxstate->rx_state = RST_STX;
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rxstate->error = RE_LEN;
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return RS_BAD_PKT;
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}
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else
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{
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/* packet ok */
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rxstate->field_c = 0;
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rxstate->rx_state = RST_DAT;
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return RS_IN_PKT;
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}
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}
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}
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case RST_DAT:
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/* dummy case (dealt with earlier) */
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#ifdef ASSERTIONS_ENABLED
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__rt_warning("ERROR: hit RST_dat in switch\n");
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#endif
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rxstate->rx_state = RST_STX;
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rxstate->error = RE_INTERNAL;
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return RS_BAD_PKT;
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case RST_CRC:
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if (rxstate->field_c == 0)
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packet->crc = 0;
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packet->crc |= (new_ch & 0xFF) << ((3 - rxstate->field_c) * 8);
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rxstate->field_c++;
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if (rxstate->field_c == 4)
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{
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/* last crc field */
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rxstate->field_c = 0;
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rxstate->rx_state = RST_ETX;
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#ifdef DO_TRACE
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__rt_trace("rxe-rcrc-%8x ", packet->crc);
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#endif
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}
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return RS_IN_PKT;
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case RST_ETX:
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if (new_ch == rxstate->config->etx)
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{
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#if defined(DEBUG) && !defined(NO_PKT_DATA)
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{
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int c;
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# ifdef DO_TRACE
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__rt_trace("\n");
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# endif
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__rt_info("RXE Data =");
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for (c=0; c < packet->len; c++)
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__rt_info("%02x", packet->data[c]);
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__rt_info("\n");
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}
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#endif
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/* check crc */
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if (rxstate->crc == packet->crc)
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{
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/* crc ok */
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rxstate->rx_state = RST_STX;
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rxstate->field_c = 0;
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return RS_GOOD_PKT;
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}
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else
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{
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#ifdef ASSERTIONS_ENABLED
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__rt_warning("Bad crc, rx calculates it should be 0x%x\n", rxstate->crc);
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#endif
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rxstate->rx_state = RST_STX;
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rxstate->error = RE_CRC;
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return RS_BAD_PKT;
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}
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}
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else if (new_ch == rxstate->config->stx)
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return unexp_stx(rxstate);
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else
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{
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rxstate->rx_state = RST_STX;
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rxstate->error = RE_NETX;
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return RS_BAD_PKT;
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}
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default:
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#ifdef ASSERTIONS_ENABLED
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__rt_warning("ERROR fell through rxengine\n");
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#endif
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rxstate->rx_state = RST_STX;
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rxstate->error = RE_INTERNAL;
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return RS_BAD_PKT;
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}
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}
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static re_status unexp_stx(struct re_state *rxstate)
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{
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#ifdef ASSERTIONS_ENABLED
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__rt_warning("Unexpected stx\n");
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#endif
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rxstate->crc = startCRC32;
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rxstate->index = 0;
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rxstate->rx_state = RST_TYP;
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rxstate->error = RE_U_STX;
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rxstate->field_c = 0;
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return RS_BAD_PKT;
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}
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static re_status unexp_etx(struct re_state *rxstate)
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{
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#ifdef ASSERTIONS_ENABLED
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__rt_warning("Unexpected etx, rxstate: index= 0x%2x, field_c=0x%2x, state=0x%2x\n", rxstate->index, rxstate->field_c, rxstate->rx_state);
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#endif
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rxstate->crc = 0;
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rxstate->index = 0;
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rxstate->rx_state = RST_STX;
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rxstate->error = RE_U_ETX;
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rxstate->field_c = 0;
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return RS_BAD_PKT;
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}
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/*
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* This can be used as the buffer allocation callback for the rx engine,
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* and makes use of angel_DD_GetBuffer() [in devdrv.h].
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*
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* Saves duplicating this callback function in every device driver that
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* uses the rx engine.
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*
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* Note that this REQUIRES that the device id is installed as ba_data
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* in the rx engine config structure for the driver.
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*/
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bool angel_DD_RxEng_BufferAlloc( struct data_packet *packet, void *cb_data )
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{
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#ifdef TARGET
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DeviceID devid = (DeviceID)cb_data;
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#else
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IGNORE(cb_data);
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#endif
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if ( packet->type < DC_NUM_CHANNELS )
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{
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/* request a buffer down from the channels layer */
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#ifdef TARGET
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packet->data = angel_DD_GetBuffer( devid, packet->type,
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packet->len );
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#else
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packet->data = malloc(packet->len);
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#endif
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if ( packet->data == NULL )
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return FALSE;
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else
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{
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packet->buf_len = packet->len;
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return TRUE;
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}
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}
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else
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{
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/* bad type field */
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return FALSE;
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}
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}
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/* EOF rx.c */
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