/*
 * (C) Copyright 2015 Leo C. <erbl259-lmu@yahoo.de>
 *
 * SPDX-License-Identifier:	GPL-2.0+
 */

#include "common.h"
#include <stdlib.h>
#include <ctype.h>
#include <stdbool.h>

#include "command.h"
#include "con-utils.h"
#include "z80-if.h"
#include "debug.h"


uint32_t detect_ramsize(void)
{
	uint32_t addr;
	uint8_t save_addr, save_0;
	const uint8_t PATTERN_1	= 0x55;
	const uint8_t PATTERN_2	= ~PATTERN_1;

	if (!(z80_bus_cmd(Request) & ZST_ACQUIRED)) {
		my_puts_P(PSTR("Bus timeout\n"));
		return  0;
	}

	save_0 = z80_read(0);
	z80_write(0, PATTERN_1);

	for (addr=1; addr < CONFIG_SYS_RAMSIZE_MAX; addr <<= 1) {
		save_addr = z80_read(addr);
		z80_write(addr, PATTERN_2);
		if (z80_read(0) != PATTERN_1 || z80_read(addr) != PATTERN_2)
			break;
		z80_write(addr, save_addr);
	}
	z80_write(0, save_0);
	z80_bus_cmd(Release);

	return addr;
}

typedef enum {
	IHX_OK,
	IHX_BROKEN,
	IHX_CHKSUMERR
} ihx_rstat_t;

typedef struct {
	ihx_rstat_t status;
	int8_t type;
	uint8_t len;
	uint16_t address;
	uint8_t data[256];
} ihex_t;


static
int get_hexdigit(void) {

	int c;
	c = toupper(my_getchar(1));
	if (isxdigit(c)) {
		c -= '0';
		if (c > 9)
			c -= ('A' - '0' - 10);
		return c;
	} else
		return -1;
}

static
int get_hexbyte(void) {

	uint8_t i,j;

	if ((i = (uint8_t) get_hexdigit()) < 0x10)
		if ((j = (uint8_t) get_hexdigit()) < 0x10) {
			return (i<<4) + j;
		}

	return -1;
}


static
int ihex_get_record(ihex_t *rec) {

	int c;
	uint8_t sum;

	rec->status = IHX_BROKEN;
	rec->len = 0;
	rec->type = 0xff;

	while ((c = my_getchar(0)) != ':') {
		if (c == 0x03)
			return -1;					/* Control-C */
		if (c == 0x04) {
			rec->status = IHX_OK;
			return 0;					/*Control-D, EOF */
		}
	}

	if ((c = get_hexbyte()) < 0)		/* Start code */
			return -1;
	sum = c;
	rec->len = c;
	if ((c = get_hexbyte()) < 0)		/* Byte Count */
			return -1;
	sum += c;
	rec->address = c * 256;
	if ((c = get_hexbyte()) < 0)		/* Address */
			return -1;
	sum += c;
	rec->address += c;
	if ((c = get_hexbyte()) < 0)		/* Record type */
		return -1;
	sum += c;
	rec->type = c;

	if (rec->len) {						/* Record Data */
		uint8_t n;

		for (n = 0; n < rec->len; n++) {
			if ((c = get_hexbyte()) < 0)
				break;
			sum += c;
			rec->data[n] = c;
		}

		if (n < rec->len) {
			return -1;
		}
	}

	c = get_hexbyte();				/* Check sum */

	if (c >= 0) {
		sum += c;
		if (sum == 0)
			rec->status = IHX_OK;
		else
			rec->status = IHX_CHKSUMERR;
	}

	return rec->len;
}


command_ret_t do_loadihex(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
{
	long offset = 0;
	uint32_t base_address = 0;
	uint32_t address_max = detect_ramsize();
	uint32_t address_high = 0;
	uint32_t address_low = address_max;
	command_ret_t rcode = CMD_RET_FAILURE;
	ihex_t rec;
	bool firstrec = true;

	(void) cmdtp; (void) flag;


	if (argc > 1)
		offset = strtol(argv[1], NULL, 16);

	printf_P(PSTR("Waiting for Intel Hex Records...\n"));

	while (ihex_get_record(&rec) > 0 &&
				rec.status == IHX_OK &&
				rec.type != 1 ) {

		switch (rec.type) {
		case 0: /* Data record */
			if (firstrec) {
				printf_P(PSTR("Loading: 0x....."));
				firstrec = false;
			}
			if (rec.len) {
				uint32_t addr = base_address + rec.address + offset;
				if (addr < address_low)
					address_low = addr;
				if (addr+rec.len > address_high)
					address_high = addr + rec.len;

//				debug("low: 0x%.5lX, high: 0x%.5lX, max: 0x%.5lX, addr: 0x%.5lX, len: %d\n",
//					address_low, address_high, address_max, addr, rec.len);
				printf_P(PSTR("\b\b\b\b\b%.5lX"), addr);
				if (addr < address_max) {
					uint32_t tmplen = address_max - addr;
					if (rec.len > tmplen)
						rec.len = tmplen;

					if (!(z80_bus_cmd(Request) & ZST_ACQUIRED)) {
						my_puts_P(PSTR("Bus timeout\n"));
						return  CMD_RET_FAILURE;
					}
					z80_write_block(rec.data,		/* src */
							addr,					/* dest */
							rec.len);				/* len */
					z80_bus_cmd(Release);
				}
			}
			break;

#if 0
		case 1: /* EOF record */
			break;
#endif
		case 2: /* Extended Segment Address Record */
			base_address = (uint32_t)((rec.data[0] << 8) + rec.data[1]) << 4;
			break;

		case 4: /* Extended Linear Address Record */
			base_address = (uint32_t)((rec.data[0] << 8) + rec.data[1]) << 16;
			break;

		case 3: /* Start Segment Address Record (ignored)*/
		case 5: /* Start Linear Address Record (ignored)*/
			break;

		}
	}

	switch (rec.status) {
	case IHX_OK:
		rcode = CMD_RET_SUCCESS;
		break;

	case IHX_BROKEN:
	case IHX_CHKSUMERR:
		printf_P(PSTR("Broken Hex Record or loading interrupted!\n"));
		break;
	}


	for (uint_fast8_t i=0; i<100; ++i) {
		/* flush input buffer */
		while (my_getchar(0) > 0)
			;
		udelay(1000);
	}


	printf_P(PSTR("\nData loaded: "));
	if (address_low >= MIN(address_high, address_max))
		printf_P(PSTR("None.\n"));
	else
		printf_P(PSTR("low: 0x%.5lX high: 0x%.5lX\n"), address_low,
				MIN(address_high, address_max) - 1);

	if (address_high > address_max)
		printf_P(PSTR("Data above highest RAM address "
			"(in range 0x%.5lX - 0x%.5lX) ignored!\n"), address_max, address_high - 1);

	return rcode;
}