/*
   * Parser/loader for IHEX formatted data.
   *
   * Copyright © 2008 David Woodhouse <dwmw2@infradead.org>
   * Copyright © 2005 Jan Harkes <jaharkes@cs.cmu.edu>
   *
   * This program is free software; you can redistribute it and/or modify
   * it under the terms of the GNU General Public License version 2 as
   * published by the Free Software Foundation.
   */
  
  #include <stdint.h>
  #include <arpa/inet.h>
  #include <stdio.h>
  #include <errno.h>
  #include <sys/types.h>
  #include <sys/stat.h>
  #include <sys/mman.h>
  #include <fcntl.h>
  #include <string.h>
  #include <unistd.h>
  #include <stdlib.h>

  #define _GNU_SOURCE
  #include <getopt.h>

  
  struct ihex_binrec {
  	struct ihex_binrec *next; /* not part of the real data structure */
          uint32_t addr;
          uint16_t len;
          uint8_t data[];
  };
  
  /**
   * nybble/hex are little helpers to parse hexadecimal numbers to a byte value
   **/
  static uint8_t nybble(const uint8_t n)
  {
         if      (n >= '0' && n <= '9') return n - '0';
         else if (n >= 'A' && n <= 'F') return n - ('A' - 10);
         else if (n >= 'a' && n <= 'f') return n - ('a' - 10);
         return 0;
  }
  
  static uint8_t hex(const uint8_t *data, uint8_t *crc)
  {
         uint8_t val = (nybble(data[0]) << 4) | nybble(data[1]);
         *crc += val;
         return val;
  }
  
  static int process_ihex(uint8_t *data, ssize_t size);
  static void file_record(struct ihex_binrec *record);
  static int output_records(int outfd);
  
  static int sort_records = 0;

  static int wide_records = 0;

  static int usage(void)

  {
  	fprintf(stderr, "ihex2fw: Convert ihex files into binary "
  		"representation for use by Linux kernel
  ");
  	fprintf(stderr, "usage: ihex2fw [<options>] <src.HEX> <dst.fw>
  ");
  	fprintf(stderr, "       -w: wide records (16-bit length)
  ");
  	fprintf(stderr, "       -s: sort records by address
  ");
  	return 1;
  }

  
  int main(int argc, char **argv)
  {
  	int infd, outfd;
  	struct stat st;
  	uint8_t *data;

  	int opt;
  
  	while ((opt = getopt(argc, argv, "ws")) != -1) {
  		switch (opt) {
  		case 'w':
  			wide_records = 1;
  			break;
  		case 's':
  			sort_records = 1;
  			break;
  		default:
  			return usage();
  		}

  	}

  
  	if (optind + 2 != argc)
  		return usage();
  
  	if (!strcmp(argv[optind], "-"))

  	    infd = 0;
  	else

  		infd = open(argv[optind], O_RDONLY);

  	if (infd == -1) {
  		fprintf(stderr, "Failed to open source file: %s",
  			strerror(errno));

  		return usage();

  	}
  	if (fstat(infd, &st)) {
  		perror("stat");
  		return 1;
  	}
  	data = mmap(NULL, st.st_size, PROT_READ, MAP_SHARED, infd, 0);
  	if (data == MAP_FAILED) {
  		perror("mmap");
  		return 1;
  	}

  	if (!strcmp(argv[optind+1], "-"))

  	    outfd = 1;
  	else

  		outfd = open(argv[optind+1], O_TRUNC|O_CREAT|O_WRONLY, 0644);

  	if (outfd == -1) {
  		fprintf(stderr, "Failed to open destination file: %s",
  			strerror(errno));

  		return usage();

  	}
  	if (process_ihex(data, st.st_size))
  		return 1;
  
  	output_records(outfd);
  	return 0;
  }
  
  static int process_ihex(uint8_t *data, ssize_t size)
  {
  	struct ihex_binrec *record;
  	uint32_t offset = 0;
  	uint8_t type, crc = 0, crcbyte = 0;
  	int i, j;
  	int line = 1;
  	int len;
  
  	i = 0;
  next_record:
  	/* search for the start of record character */
  	while (i < size) {
  		if (data[i] == '
  ') line++;
  		if (data[i++] == ':') break;
  	}
  
  	/* Minimum record length would be about 10 characters */
  	if (i + 10 > size) {
  		fprintf(stderr, "Can't find valid record at line %d
  ", line);
  		return -EINVAL;
  	}
  
  	len = hex(data + i, &crc); i += 2;

  	if (wide_records) {
  		len <<= 8;
  		len += hex(data + i, &crc); i += 2;
  	}

  	record = malloc((sizeof (*record) + len + 3) & ~3);
  	if (!record) {
  		fprintf(stderr, "out of memory for records
  ");
  		return -ENOMEM;
  	}
  	memset(record, 0, (sizeof(*record) + len + 3) & ~3);
  	record->len = len;
  
  	/* now check if we have enough data to read everything */
  	if (i + 8 + (record->len * 2) > size) {
  		fprintf(stderr, "Not enough data to read complete record at line %d
  ",
  			line);
  		return -EINVAL;
  	}
  
  	record->addr  = hex(data + i, &crc) << 8; i += 2;
  	record->addr |= hex(data + i, &crc); i += 2;
  	type = hex(data + i, &crc); i += 2;
  
  	for (j = 0; j < record->len; j++, i += 2)
  		record->data[j] = hex(data + i, &crc);
  
  	/* check CRC */
  	crcbyte = hex(data + i, &crc); i += 2;
  	if (crc != 0) {
  		fprintf(stderr, "CRC failure at line %d: got 0x%X, expected 0x%X
  ",
  			line, crcbyte, (unsigned char)(crcbyte-crc));
  		return -EINVAL;
  	}
  
  	/* Done reading the record */
  	switch (type) {
  	case 0:
  		/* old style EOF record? */
  		if (!record->len)
  			break;
  
  		record->addr += offset;
  		file_record(record);
  		goto next_record;
  
  	case 1: /* End-Of-File Record */
  		if (record->addr || record->len) {
  			fprintf(stderr, "Bad EOF record (type 01) format at line %d",
  				line);
  			return -EINVAL;
  		}
  		break;
  
  	case 2: /* Extended Segment Address Record (HEX86) */
  	case 4: /* Extended Linear Address Record (HEX386) */
  		if (record->addr || record->len != 2) {
  			fprintf(stderr, "Bad HEX86/HEX386 record (type %02X) at line %d
  ",
  				type, line);
  			return -EINVAL;
  		}
  
  		/* We shouldn't really be using the offset for HEX86 because
  		 * the wraparound case is specified quite differently. */
  		offset = record->data[0] << 8 | record->data[1];
  		offset <<= (type == 2 ? 4 : 16);
  		goto next_record;
  
  	case 3: /* Start Segment Address Record */
  	case 5: /* Start Linear Address Record */
  		if (record->addr || record->len != 4) {
  			fprintf(stderr, "Bad Start Address record (type %02X) at line %d
  ",
  				type, line);
  			return -EINVAL;
  		}
  
  		/* These records contain the CS/IP or EIP where execution
  		 * starts. Don't really know what to do with them. */
  		goto next_record;
  
  	default:
  		fprintf(stderr, "Unknown record (type %02X)
  ", type);
  		return -EINVAL;
  	}
  
  	return 0;
  }
  
  static struct ihex_binrec *records;
  
  static void file_record(struct ihex_binrec *record)
  {
  	struct ihex_binrec **p = &records;
  
  	while ((*p) && (!sort_records || (*p)->addr < record->addr))
  		p = &((*p)->next);
  
  	record->next = *p;
  	*p = record;
  }
  
  static int output_records(int outfd)
  {

  	unsigned char zeroes[6] = {0, 0, 0, 0, 0, 0};

  	struct ihex_binrec *p = records;
  
  	while (p) {
  		uint16_t writelen = (p->len + 9) & ~3;
  
  		p->addr = htonl(p->addr);

  		p->len = htons(p->len);

  		write(outfd, &p->addr, writelen);
  		p = p->next;
  	}
  	/* EOF record is zero length, since we don't bother to represent
  	   the type field in the binary version */

  	write(outfd, zeroes, 6);

  	return 0;
  }