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