| 1 | /* |
| 2 | * Copyright (C) 1995 Advanced RISC Machines Limited. All rights reserved. |
| 3 | * |
| 4 | * This software may be freely used, copied, modified, and distributed |
| 5 | * provided that the above copyright notice is preserved in all copies of the |
| 6 | * software. |
| 7 | */ |
| 8 | |
| 9 | /*-*-C-*- |
| 10 | * |
| 11 | * $Revision$ |
| 12 | * $Date$ |
| 13 | * |
| 14 | * |
| 15 | * Project: ANGEL |
| 16 | * |
| 17 | * Title: Character reception engine |
| 18 | */ |
| 19 | |
| 20 | #include <stdarg.h> /* ANSI varargs support */ |
| 21 | #include "angel.h" /* Angel system definitions */ |
| 22 | #include "angel_endian.h" /* Endian independant memory access macros */ |
| 23 | #include "crc.h" /* crc generation definitions and headers */ |
| 24 | #include "rxtx.h" |
| 25 | #include "channels.h" |
| 26 | #include "buffers.h" |
| 27 | #ifdef TARGET |
| 28 | # include "devdriv.h" |
| 29 | #endif |
| 30 | #include "logging.h" |
| 31 | |
| 32 | static re_status unexp_stx(struct re_state *rxstate); |
| 33 | static re_status unexp_etx(struct re_state *rxstate); |
| 34 | |
| 35 | /* bitfield for the rx_engine state */ |
| 36 | typedef enum rx_state_flag{ |
| 37 | RST_STX, |
| 38 | RST_TYP, |
| 39 | RST_LEN, |
| 40 | RST_DAT, |
| 41 | RST_CRC, |
| 42 | RST_ETX, |
| 43 | RST_ESC = (0x1 << 0x3) |
| 44 | } rx_state_flag; |
| 45 | |
| 46 | void Angel_RxEngineInit(const struct re_config *rxconfig, |
| 47 | struct re_state *rxstate) |
| 48 | { |
| 49 | rxstate->rx_state = RST_STX; |
| 50 | rxstate->field_c = 0; |
| 51 | rxstate->index = 0; |
| 52 | rxstate->crc = 0; |
| 53 | rxstate->error = RE_OKAY; |
| 54 | rxstate->config = rxconfig; |
| 55 | } |
| 56 | |
| 57 | re_status Angel_RxEngine(unsigned char new_ch, struct data_packet *packet, |
| 58 | struct re_state *rxstate) |
| 59 | { |
| 60 | /* |
| 61 | * TODO: add the flow control bits in |
| 62 | * Note: We test for the data field in a seperate case so we can |
| 63 | * completely avoid entering the switch for most chars |
| 64 | */ |
| 65 | |
| 66 | /* see if we're expecting a escaped char */ |
| 67 | if ((rxstate->rx_state & RST_ESC) == RST_ESC) |
| 68 | { |
| 69 | /* unescape the char and unset the flag*/ |
| 70 | new_ch &= ~serial_ESCAPE; |
| 71 | #ifdef DO_TRACE |
| 72 | __rt_trace("rxe-echar-%2x ", new_ch); |
| 73 | #endif |
| 74 | rxstate->rx_state &= ~RST_ESC; |
| 75 | } |
| 76 | else if ( (1 << new_ch) & rxstate->config->esc_set ) |
| 77 | { |
| 78 | /* see if the incoming char is a special one */ |
| 79 | if (new_ch == rxstate->config->esc) |
| 80 | { |
| 81 | #ifdef DO_TRACE |
| 82 | __rt_trace("rxe-esc "); |
| 83 | #endif |
| 84 | rxstate->rx_state |= RST_ESC; |
| 85 | return RS_IN_PKT; |
| 86 | } |
| 87 | else |
| 88 | { |
| 89 | /* |
| 90 | * must be a normal packet so do some unexpected etx/stx checking |
| 91 | * we haven't been told to escape or received an escape so unless |
| 92 | * we are expecting an stx or etx then we can take the unexpected |
| 93 | * stx/etx trap |
| 94 | */ |
| 95 | if ((new_ch == (rxstate->config->stx)) && (rxstate->rx_state != RST_STX)) |
| 96 | return unexp_stx(rxstate); |
| 97 | if ((new_ch == (rxstate->config->etx)) && (rxstate->rx_state != RST_ETX)) |
| 98 | return unexp_etx(rxstate); |
| 99 | } |
| 100 | } |
| 101 | |
| 102 | if (rxstate->rx_state == RST_DAT) |
| 103 | { |
| 104 | /* |
| 105 | * do this to speed up the common case, no real penalty for |
| 106 | * other cases |
| 107 | */ |
| 108 | #ifdef DO_TRACE |
| 109 | __rt_trace("rxe-dat "); |
| 110 | #endif |
| 111 | |
| 112 | rxstate->crc = crc32(&new_ch, 1, rxstate->crc); |
| 113 | (packet->data)[rxstate->index++] = (unsigned int)new_ch & 0xff; |
| 114 | |
| 115 | if (rxstate->index == packet->len) |
| 116 | rxstate->rx_state = RST_CRC; |
| 117 | |
| 118 | return RS_IN_PKT; |
| 119 | } |
| 120 | |
| 121 | /* |
| 122 | * Now that the common case is out of the way we can test for everything |
| 123 | * else without worrying quite so much about the speed, changing the |
| 124 | * order to len,crc,stx,etx,typ might gain a tiny bit of speed but lets |
| 125 | * leave that for the moment |
| 126 | */ |
| 127 | switch (rxstate->rx_state) |
| 128 | { |
| 129 | case RST_STX: |
| 130 | if (new_ch == rxstate->config->stx) |
| 131 | { |
| 132 | rxstate->rx_state = RST_TYP; |
| 133 | rxstate->error = RE_OKAY; |
| 134 | rxstate->crc = startCRC32; |
| 135 | rxstate->index = 0; |
| 136 | return RS_IN_PKT; |
| 137 | } |
| 138 | else |
| 139 | { |
| 140 | rxstate->error = RE_OKAY; |
| 141 | return RS_WAIT_PKT; |
| 142 | } |
| 143 | |
| 144 | case RST_TYP: |
| 145 | packet->type = (DevChanID)new_ch; |
| 146 | rxstate->rx_state = RST_LEN; |
| 147 | rxstate->error = RE_OKAY; |
| 148 | rxstate->field_c = 0; /* set up here for the length that follows */ |
| 149 | #ifdef DO_TRACE |
| 150 | __rt_trace("rxe-type-%2x ", packet->type); |
| 151 | #endif |
| 152 | rxstate->crc = crc32(&new_ch, 1, rxstate->crc); |
| 153 | |
| 154 | return RS_IN_PKT; |
| 155 | |
| 156 | case RST_LEN: |
| 157 | rxstate->crc = crc32(&new_ch, 1, rxstate->crc); |
| 158 | |
| 159 | if (rxstate->field_c++ == 0) |
| 160 | { |
| 161 | /* first length byte */ |
| 162 | packet->len = ((unsigned int)new_ch) << 8; |
| 163 | return RS_IN_PKT; |
| 164 | } |
| 165 | else |
| 166 | { |
| 167 | /* got the whole legth */ |
| 168 | packet->len |= new_ch; |
| 169 | #ifdef DO_TRACE |
| 170 | __rt_trace("rxe-len-%4x\n", packet->len); |
| 171 | #endif |
| 172 | |
| 173 | /* check that the length is ok */ |
| 174 | if (packet->len == 0) |
| 175 | { |
| 176 | /* empty pkt */ |
| 177 | rxstate->field_c = 0; |
| 178 | rxstate->rx_state = RST_CRC; |
| 179 | return RS_IN_PKT; |
| 180 | } |
| 181 | else |
| 182 | { |
| 183 | if (packet->data == NULL) |
| 184 | { |
| 185 | /* need to alloc the data buffer */ |
| 186 | if (!rxstate->config->ba_callback( |
| 187 | packet, rxstate->config->ba_data)) { |
| 188 | rxstate->rx_state = RST_STX; |
| 189 | rxstate->error = RE_INTERNAL; |
| 190 | return RS_BAD_PKT; |
| 191 | } |
| 192 | } |
| 193 | |
| 194 | if (packet->len > packet->buf_len) |
| 195 | { |
| 196 | /* pkt bigger than buffer */ |
| 197 | rxstate->field_c = 0; |
| 198 | rxstate->rx_state = RST_STX; |
| 199 | rxstate->error = RE_LEN; |
| 200 | return RS_BAD_PKT; |
| 201 | } |
| 202 | else |
| 203 | { |
| 204 | /* packet ok */ |
| 205 | rxstate->field_c = 0; |
| 206 | rxstate->rx_state = RST_DAT; |
| 207 | return RS_IN_PKT; |
| 208 | } |
| 209 | } |
| 210 | } |
| 211 | |
| 212 | case RST_DAT: |
| 213 | /* dummy case (dealt with earlier) */ |
| 214 | #ifdef ASSERTIONS_ENABLED |
| 215 | __rt_warning("ERROR: hit RST_dat in switch\n"); |
| 216 | #endif |
| 217 | rxstate->rx_state = RST_STX; |
| 218 | rxstate->error = RE_INTERNAL; |
| 219 | return RS_BAD_PKT; |
| 220 | |
| 221 | case RST_CRC: |
| 222 | if (rxstate->field_c == 0) |
| 223 | packet->crc = 0; |
| 224 | |
| 225 | packet->crc |= (new_ch & 0xFF) << ((3 - rxstate->field_c) * 8); |
| 226 | rxstate->field_c++; |
| 227 | |
| 228 | if (rxstate->field_c == 4) |
| 229 | { |
| 230 | /* last crc field */ |
| 231 | rxstate->field_c = 0; |
| 232 | rxstate->rx_state = RST_ETX; |
| 233 | #ifdef DO_TRACE |
| 234 | __rt_trace("rxe-rcrc-%8x ", packet->crc); |
| 235 | #endif |
| 236 | } |
| 237 | |
| 238 | return RS_IN_PKT; |
| 239 | |
| 240 | case RST_ETX: |
| 241 | if (new_ch == rxstate->config->etx) |
| 242 | { |
| 243 | #if defined(DEBUG) && !defined(NO_PKT_DATA) |
| 244 | { |
| 245 | int c; |
| 246 | # ifdef DO_TRACE |
| 247 | __rt_trace("\n"); |
| 248 | # endif |
| 249 | __rt_info("RXE Data ="); |
| 250 | for (c=0; c < packet->len; c++) |
| 251 | __rt_info("%02x", packet->data[c]); |
| 252 | __rt_info("\n"); |
| 253 | } |
| 254 | #endif |
| 255 | |
| 256 | /* check crc */ |
| 257 | if (rxstate->crc == packet->crc) |
| 258 | { |
| 259 | /* crc ok */ |
| 260 | rxstate->rx_state = RST_STX; |
| 261 | rxstate->field_c = 0; |
| 262 | return RS_GOOD_PKT; |
| 263 | } |
| 264 | else |
| 265 | { |
| 266 | #ifdef ASSERTIONS_ENABLED |
| 267 | __rt_warning("Bad crc, rx calculates it should be 0x%x\n", rxstate->crc); |
| 268 | #endif |
| 269 | rxstate->rx_state = RST_STX; |
| 270 | rxstate->error = RE_CRC; |
| 271 | return RS_BAD_PKT; |
| 272 | } |
| 273 | } |
| 274 | else if (new_ch == rxstate->config->stx) |
| 275 | return unexp_stx(rxstate); |
| 276 | else |
| 277 | { |
| 278 | rxstate->rx_state = RST_STX; |
| 279 | rxstate->error = RE_NETX; |
| 280 | return RS_BAD_PKT; |
| 281 | } |
| 282 | |
| 283 | default: |
| 284 | #ifdef ASSERTIONS_ENABLED |
| 285 | __rt_warning("ERROR fell through rxengine\n"); |
| 286 | #endif |
| 287 | rxstate->rx_state = RST_STX; |
| 288 | rxstate->error = RE_INTERNAL; |
| 289 | return RS_BAD_PKT; |
| 290 | } |
| 291 | } |
| 292 | |
| 293 | static re_status unexp_stx(struct re_state *rxstate) |
| 294 | { |
| 295 | #ifdef ASSERTIONS_ENABLED |
| 296 | __rt_warning("Unexpected stx\n"); |
| 297 | #endif |
| 298 | rxstate->crc = startCRC32; |
| 299 | rxstate->index = 0; |
| 300 | rxstate->rx_state = RST_TYP; |
| 301 | rxstate->error = RE_U_STX; |
| 302 | rxstate->field_c = 0; |
| 303 | return RS_BAD_PKT; |
| 304 | } |
| 305 | |
| 306 | static re_status unexp_etx(struct re_state *rxstate) |
| 307 | { |
| 308 | #ifdef ASSERTIONS_ENABLED |
| 309 | __rt_warning("Unexpected etx, rxstate: index= 0x%2x, field_c=0x%2x, state=0x%2x\n", rxstate->index, rxstate->field_c, rxstate->rx_state); |
| 310 | #endif |
| 311 | rxstate->crc = 0; |
| 312 | rxstate->index = 0; |
| 313 | rxstate->rx_state = RST_STX; |
| 314 | rxstate->error = RE_U_ETX; |
| 315 | rxstate->field_c = 0; |
| 316 | return RS_BAD_PKT; |
| 317 | } |
| 318 | |
| 319 | /* |
| 320 | * This can be used as the buffer allocation callback for the rx engine, |
| 321 | * and makes use of angel_DD_GetBuffer() [in devdrv.h]. |
| 322 | * |
| 323 | * Saves duplicating this callback function in every device driver that |
| 324 | * uses the rx engine. |
| 325 | * |
| 326 | * Note that this REQUIRES that the device id is installed as ba_data |
| 327 | * in the rx engine config structure for the driver. |
| 328 | */ |
| 329 | bool angel_DD_RxEng_BufferAlloc( struct data_packet *packet, void *cb_data ) |
| 330 | { |
| 331 | #ifdef TARGET |
| 332 | DeviceID devid = (DeviceID)cb_data; |
| 333 | #else |
| 334 | IGNORE(cb_data); |
| 335 | #endif |
| 336 | |
| 337 | if ( packet->type < DC_NUM_CHANNELS ) |
| 338 | { |
| 339 | /* request a buffer down from the channels layer */ |
| 340 | #ifdef TARGET |
| 341 | packet->data = angel_DD_GetBuffer( devid, packet->type, |
| 342 | packet->len ); |
| 343 | #else |
| 344 | packet->data = malloc(packet->len); |
| 345 | #endif |
| 346 | if ( packet->data == NULL ) |
| 347 | return FALSE; |
| 348 | else |
| 349 | { |
| 350 | packet->buf_len = packet->len; |
| 351 | return TRUE; |
| 352 | } |
| 353 | } |
| 354 | else |
| 355 | { |
| 356 | /* bad type field */ |
| 357 | return FALSE; |
| 358 | } |
| 359 | } |
| 360 | |
| 361 | /* EOF rx.c */ |