/*
 * lpc111x-isp/lpc111x.c - LPC111x/LPC11Cxx ISP programmer
 *
 * Written 2012 by Werner Almesberger
 * Copyright 2012 Werner Almesberger
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 */


#define	_GNU_SOURCE	/* for vasprintf */
#include <stdarg.h>
#include <stdlib.h>
#include <stdio.h>
#include <unistd.h>
#include <string.h>
#include <alloca.h>
#include <assert.h>
#include <sys/types.h>

#include <ubb/ubb.h>
#include <ubb/swuart.h>


#define	TGT_nRESET	UBB_CMD
#define	TGT_nISP	UBB_DAT1
#define	TGT_TX		UBB_DAT3
#define	TGT_RX		UBB_DAT2

#define	HOST_RX		TGT_TX
#define	HOST_TX		TGT_RX

#define	BPS		115200

#define	MAX_BUF		10000	/* receive buffer */

#define	AUTOBAUD_TRIES	10
#define	SYNC		"Synchronized"

#define	MAX_RECORD	45	/* data bytes per uuencoded record */

/*
 * UM 26.4.8 pg 416 says 0x1000017C to 0x1000025B and the last 256+32 bytes
 * of the RAM are taken.
 *
 * UM 26.5.4 pg 418 hints 0x10000300 is a good place.
 */

#define	RAM_BUFFER	0x10000300
#define	SECTOR		4096
#define	PAGE		256

static int verbose = 0;
static int quiet = 0;


/* ----- Debugging and tracing --------------------------------------------- */


static void trace(const char *label, const uint8_t *s, int len)
{
	const uint8_t *end = s+len;

	if (label)
		fprintf(stderr, "%s ", label);
	for (end = s+len; s != end; s++) {
		if (*s >= ' ' && *s <= '~')
			fprintf(stderr, "%c", *s);
		else if (*s == 10)
			fprintf(stderr, "\\n");
		else if (*s == 13)
			fprintf(stderr, "\\r");
		else
			fprintf(stderr, "\\%02o", *s);
	}
	fprintf(stderr, "\n");
}


static void trace_out(const void *s, int len)
{
	trace(">>>", s, len);
}


static void trace_in(const void *s, int len)
{
	trace("<<<", s, len);
}


/* ----- Dialog functions -------------------------------------------------- */


static const char *dialog_fixed(int idle, const char *msg)
{
	static char *res = NULL;
	int msg_len = strlen(msg);
	char *tx_buf = alloca(msg_len+3);
	char *rx_buf = alloca(MAX_BUF);
	char *s, *t;
	int got;

	memcpy(tx_buf, msg, msg_len);
	memcpy(tx_buf+msg_len, "\r\n", 2);

	if (verbose)
		trace_out(tx_buf, msg_len+2);
	got = swuart_trx(tx_buf, msg_len+2, rx_buf, MAX_BUF, idle, idle);
	if (verbose)
		trace_in(rx_buf, got);

	if (got < msg_len+2) {
		fprintf(stderr, "response too short for echo\n");
		exit(1);
	}
	if (memcmp(rx_buf, msg, msg_len) ||
	    rx_buf[msg_len] != '\r' || rx_buf[msg_len+1] != '\n') {
		fprintf(stderr, "echo mismatch\n");
		exit(1);
	}

	if (memchr(rx_buf, 0, got)) {
		fprintf(stderr, "NUL in response\n");
		exit(1);
	}

	rx_buf += msg_len+2;
	got -= msg_len+2;

	res = realloc(res, got+1);
	if (!res) {
		perror("realloc");
		exit(1);
	}

	t = res;
	for (s = rx_buf; s != rx_buf+got; s++) {
		if (*s == '\r') {
			if (s+1 != rx_buf+got && s[1] == '\n')
				continue;
			fprintf(stderr, "\\r without \\n\n");
			exit(1);
		}
		if (*s == '\n' && s+1 == rx_buf+got)
			break;
		*t++ = *s;
	}
	*t = 0;

	return res;
}


static const char *vdialog(int idle, const char *cmd, va_list ap)
{
	char *msg;

	vasprintf(&msg, cmd, ap);
	return dialog_fixed(idle, msg);
}


static const char *dialog(int idle, const char *cmd, ...)
{
	va_list ap;
	const char *res;

	va_start(ap, cmd);
	res = vdialog(idle, cmd, ap);
	va_end(ap);
	return res;
}


static const char *dialog_rc(int idle, const char *cmd, ...)
{
	va_list ap;
	const char *res, *p;
	unsigned  rc;

	va_start(ap, cmd);
	res = vdialog(idle, cmd, ap);
	va_end(ap);

	p = strchr(res, '\n');
	if (!p)
		p = strchr(res, 0);
	if (sscanf(res, "%u", &rc) != 1) {
		fprintf(stderr, "invalid status\n");
		exit(1);
	}

	if (rc != 0) {
		fprintf(stderr, "rc %d\n", rc);
		exit(1);
	}

	return p+1;
}


static int autobaud(void)
{
	uint8_t reply[100];
	int i, got;
	const char *res;

	for (i = 0; i != AUTOBAUD_TRIES; i++) {
		CLR(TGT_nRESET);
		usleep(10);	/* DS Table 9 pg 29 says min 50 ns */
		SET(TGT_nRESET);

		usleep(5*1000);	/* UM 26.3.1 pg 408 says max 3 ms */

		got = swuart_trx("?", 1, reply, sizeof(reply), 1000, 100);
		if (got != strlen(SYNC)+2 || memcmp(reply, SYNC "\r\n", got))
			continue;

		res = dialog(100, SYNC);

		if (!strcmp(res, "OK"))
			return 1;
	}
	return 0;
}


/* ----- Devices database -------------------------------------------------- */


static const struct device {
	const char *name;
	unsigned id;
	int flash_kb;
} devices[] = {
	{ "LPC1112FHxxx/202",	0x2524902b,	16	},
	{ NULL, }
}, *device = NULL;


static void identify(void)
{
	const char *res;
	unsigned id, serial[4];

	res = dialog_rc(100, "J");
	if (sscanf(res, "%u", &id) != 1) {
		fprintf(stderr, "J: cannot parse ID \"%s\"\n", res);
		exit(1);
	}

	res = dialog_rc(100, "N");
	if (sscanf(res, "%u %u %u %u",
	    serial, serial+1, serial+2, serial+3) != 4) {
		fprintf(stderr, "N: cannot parse serial number\"%s\"\n", res);
		exit(1);
	}

	for (device = devices; device->name; device++)
		if (device->id == id) {
			if (!quiet)
				fprintf(stderr, "%s (0x%04x %04x) %d kB "
				    "serial %08x.%08x.%08x.%08x\n",
				    device->name, id >> 16, id & 0xffff,
				    device->flash_kb,
				    serial[0], serial[1], serial[2], serial[3]);
			return;
		}

	fprintf(stderr, "unknown device 0x%04x %04x\n", id >> 16, id & 0xffff);
	exit(1);
}


/* ----- Flash programming ------------------------------------------------- */


static int ms_to_bits(int ms)
{
	return (BPS*ms+999)/1000;
}


static char uuechar(uint8_t b)
{
	b &= 0x3f;
	return b ? b+32 : 0x60;
}


static const char *uuencode(const uint8_t *p, int len)
{
	static char buf[80];
	char *t = buf;
	const uint8_t *end = p+len;
	unsigned tmp = 0; /* initialize to prevent compiler complaints */
	int i;

	*t++ = len+32;
	while (p != end) {
		for (i = 0; i != 3; i++)
			if (p == end)
				tmp <<= 8;
			else
				tmp = tmp << 8 | *p++;
		*t++ = uuechar(tmp >> 18);
		*t++ = uuechar(tmp >> 12);
		*t++ = uuechar(tmp >> 6);
		*t++ = uuechar(tmp);
	}
	*t = 0;
	return buf;
}


static void flash_erase_sectors(unsigned addr, unsigned len)
{
	unsigned from = addr/SECTOR;
	unsigned to = (addr+len-1)/SECTOR;

	assert(!(addr & (SECTOR-1)));
	assert(!(len & (SECTOR-1)));

	dialog_rc(100, "P %d %d", from, to);

	/* DS 10.2 pg 77: t_er(max) = 105 ms */
	dialog_rc(ms_to_bits(200), "E %d %d", from, to);
}


static void flash_write_page(unsigned addr, const uint8_t *buf)
{
	unsigned sector = addr/SECTOR;
	unsigned sum;
	int chunk, i;
	const char *res;

	assert(!(addr & (PAGE-1)));

	dialog_rc(100, "W %u %u", RAM_BUFFER, PAGE);
	for (i = 0; i != PAGE; i += chunk) {
		chunk = PAGE-i > MAX_RECORD ? MAX_RECORD : PAGE-i;
		dialog(100, "%s", uuencode(buf+i, chunk));
	}

	sum = 0;
	for (i = 0; i != PAGE; i++)
		sum += buf[i];

	res = dialog(100, "%u", sum);
	if (strcmp(res, "OK")) {
		fprintf(stderr, "non-OK response: \"%s\"\n", res);
		exit(1);
	}

	dialog_rc(100, "P %d %d", sector, sector);

	/* DS 10.2 pg 77: t_prog(max) = 1.05 ms */
	dialog_rc(ms_to_bits(2), "C %d %u %d", addr, RAM_BUFFER, PAGE);
}


static void flash_write(unsigned addr, const uint8_t *p, int len,
    int erase_all)
{
	uint8_t page[PAGE];

	assert(!(addr & (PAGE-1)));

	dialog_rc(100, "U 23130");
	if (erase_all)
		flash_erase_sectors(0, device->flash_kb << 10);
	else
		flash_erase_sectors(addr & ~(SECTOR-1),
		    (addr+len+SECTOR-1) & ~(SECTOR-1));
	while (len > 0) {
		if (len < PAGE) {
			memcpy(page, p, len);
			memset(page+len, 0xff, PAGE-len);
		} else {
			memcpy(page, p, PAGE);
			p += PAGE;
		}
		flash_write_page(addr, page);
		addr += PAGE;
		len -= PAGE;
	}
}


static void flash_file(FILE *file)
{
	uint8_t buf[(device->flash_kb << 10)+1];
	size_t got;

	got = fread(buf, 1, sizeof(buf), file);
	if (!got) {
		if (ferror(file))
			perror("fread");
		else
			fprintf(stderr, "file is empty\n");
		exit(1);
	}
	if (got > device->flash_kb << 10) {
		fprintf(stderr, "file is larger than flash (%d kB)\n",
		    device->flash_kb);
		exit(1);
	}
	flash_write(0, buf, got, 1);
}


/* ----- Flash dump -------------------------------------------------------- */


/*
 * The uuencoding algorithm is described in AN11229.
 * It's the same as used by uuencode.
 */


static uint8_t uudchar(char c)
{
	if (c <= 0x20 && c > 0x60) {
		fprintf(stderr, "invalid UU character '%c'\n", c);
		exit(1);
	}
	return c == 0x60 ? 0 : c-32;
}


static int uudecode(const char *s, uint8_t *buf)
{
	int len, uu_len;
	const char *nl;
	const uint8_t *end;

	len = *s-32;
	if (len < 0 || len > MAX_RECORD) {
		fprintf(stderr, "invalid UU length (%d)\n", len);
		exit(1);
	}
	nl = strchr(++s, '\n');
	if (!nl) {
		fprintf(stderr, "no \\n at end of UU record\n");
		exit(1);
	}
	uu_len = nl-s;
	if (uu_len & 3) {
		fprintf(stderr, "UU length %d not a multiple of 4\n", uu_len);
		exit(1);
	}
	if ((len+2)/3 != uu_len/4) {
		fprintf(stderr, "UU length %d vs. %d bytes (\"%.*s\")\n",
		    uu_len, len, nl-s+1, s-1);
		exit(1);
	}

	end = buf+len;
	while (buf != end) {
		unsigned tmp = uudchar(s[0]) << 18 | uudchar(s[1]) << 12 |
		    uudchar(s[2]) << 6 | uudchar(s[3]);

		*buf++ = tmp >> 16;
		if (buf != end)
			*buf++ = tmp >> 8;
		if (buf != end)
			*buf++ = tmp;
		s += 4;
	}
	return len;
}


static void dump(void)
{
	int addr = 0, end;
	unsigned sum = 0, check;
	const char *res, *nl;
	int got, wrote, i;

	end = device->flash_kb << 10;
	res = dialog_rc(100, "R 0 %u", end);
	while (addr != end) {
		while (1) {
			uint8_t buf[MAX_RECORD];

			nl = strchr(res, '\n');
			if (!nl)
				break;
			got = uudecode(res, buf);
			for (i = 0; i != got; i++)
				sum += buf[i];
			wrote = fwrite(buf, 1, got, stdout);
			if (wrote != got) {
				perror("fwrite");
				exit(1);
			}
			addr += got;
			res = nl+1;
		}
		if (sscanf(res, "%u", &check) != 1) {
			fprintf(stderr, "can't parse checksum \"%s\"\n", res);
			exit(1);
		}
		if (check != sum) {
			fprintf(stderr, "checksum error: got %u received %u\n",
			    sum, check);
			exit(1);
		}
		res = dialog(100, "OK");
		sum = 0;
	}
}


/* ----- ISP session ------------------------------------------------------- */


static void at_exit(void)
{
	ubb_close(0);
}


static void start_isp(int power)
{
	const char *res;

	if (ubb_open(0) < 0) {
		perror("ubb_open");
		exit(1);
	}
	atexit(at_exit);

	if (power)
		ubb_power(1);

	usleep(100*1000);

	SET(TGT_nRESET);
	OUT(TGT_nRESET);

	CLR(TGT_nISP);
	OUT(TGT_nISP);

	if (swuart_open(HOST_TX, HOST_RX, BPS) < 0) {
		perror("swuart_open");
		exit(1);
	}

	if (!autobaud()) {
		fprintf(stderr, "target is not responding\n");
		exit(1);
	}

	res = dialog(100, "12000");
	if (strcmp(res, "OK")) {
		fprintf(stderr, "cannot set clock rate\n");
		exit(1);
	}
}


/* ----- Reset and run target ---------------------------------------------- */


static void run_target(int power)
{
	if (ubb_open(0) < 0) {
		perror("ubb_open");
		exit(1);
	}

	if (power)
		ubb_power(1);

	SET(TGT_nRESET);
	OUT(TGT_nRESET);

	IN(TGT_nISP);

	CLR(TGT_nRESET);
	usleep(10);	/* DS Table 9 pg 29 says min 50 ns */
	SET(TGT_nRESET);

	ubb_close(UBB_nPWR | TGT_nRESET | TGT_nISP);
}


/* ----- Command-line processing ------------------------------------------- */


static void usage(const char *name)
{
	fprintf(stderr,
"usage: %s [-n] [-q] [-v ...] [file.bin]\n"
"       %s [-n] -r\n\n"
"  -n  don't power the device\n"
"  -q  suppress basic progress messages\n"
"  -r  reset the target and let it run\n"
"  -v  increase verbosity level\n"
    , name, name);
	exit(1);
}


int main(int argc, char **argv)
{
	FILE *file = NULL;
	int power = 1;
	int run = 0;
	int c;

	while ((c = getopt(argc, argv, "nqrv")) != EOF)
		switch (c) {
		case 'n':
			power = 0;
			break;
		case 'q':
			quiet = 1;
			break;
		case 'r':
			run = 1;
			break;
		case 'v':
			verbose++;
			break;
		default:
			usage(*argv);
		}

	if (run) {
		if (quiet || verbose || argc != optind)
			usage(*argv);
		run_target(power);
		return 0;
	}

	switch (argc-optind) {
	case 0:
		break;
	case 1:
		if (!strcmp(argv[optind], "-"))
			file = stdin;
		else {
			file = fopen(argv[optind], "r");
			if (!file) {
				perror(argv[optind]);
				exit(1);
			}
		}
		break;
	default:
		usage(*argv);
	}

	start_isp(power);

	identify();

	if (file)
		flash_file(file);
	else
		dump();

	return 0;
}