http://lists.denx.de/pipermail/u-boot/2012-May/125296.html
http://patchwork.ozlabs.org/patch/161566/
---

diff --git a/doc/kwboot.1 b/doc/kwboot.1
new file mode 100644
index 0000000..ed08398
--- /dev/null
+++ b/doc/kwboot.1
@@ -0,0 +1,84 @@
+.TH KWBOOT 1 "2012-05-19"
+
+.SH NAME
+kwboot \- Boot Marvell Kirkwood SoCs over a serial link.
+.SH SYNOPSIS
+.B kwboot
+.RB [ "-b \fIimage\fP" ]
+.RB [ "-p" ]
+.RB [ "-t" ]
+.RB [ "-B \fIbaudrate\fP" ]
+.RB \fITTY\fP
+.SH "DESCRIPTION"
+
+The \fBmkimage\fP program boots boards based on Marvell's Kirkwood
+platform over their integrated UART. Boot image files will typically
+contain a second stage boot loader, such as U-Boot. The image file
+must conform to Marvell's BootROM firmware image format
+(\fIkwbimage\fP), created using a tool such as \fBmkimage\fP.
+
+Following power-up or a system reset, system BootROM code polls the
+UART for a brief period of time, sensing a handshake message which
+initiates an image upload. This program sends this boot message until
+it receives a positive acknowledgement. The image is transfered using
+Xmodem.
+
+Additionally, this program implements a minimal terminal mode, which
+can be used either standalone, or entered immediately following boot
+image transfer completion. This is often useful to catch early boot
+messages, or to manually interrupt a default boot procedure performed
+by the second-stage loader.
+
+.SH "OPTIONS"
+
+.TP
+.BI "\-b \fIimage\fP"
+Handshake; then upload file \fIimage\fP over \fITTY\fP.
+
+Note that for the encapsulated boot code to be executed, \fIimage\fP
+must be of type "UART boot" (0x69). Boot images of different types,
+such as backup images of vendor firmware downloaded from flash memory
+(type 0x8B), will not work (or not as expected). See \fB-p\fP for a
+workaround.
+
+This mode writes handshake status and upload progress indication to
+stdout.
+
+.TP
+.BI "\-p"
+In combination with \fB-b\fP, patches the header in \fIimage\fP prior
+to upload, to "UART boot" type.
+
+This option attempts on-the-fly conversion of some none-UART image
+types, such as images which were originally formatted to be stored in
+flash memory.
+
+Conversion is performed in memory. The contents of \fIimage\fP will
+not be altered.
+
+.TP
+.BI "\-t"
+Run a terminal program, connecting standard input and output to
+.RB \fITTY\fP.
+
+If used in combination with \fB-b\fP, terminal mode is entered
+immediately following a successful image upload.
+
+If standard I/O streams connect to a console, this mode will terminate
+after receiving 'ctrl-\\' followed by 'c' from console input.
+
+.TP
+.BI "\-B \fIbaudrate\fP"
+Adjust the baud rate on \fITTY\fP. Default rate is 115200.
+
+.SH "SEE ALSO"
+.PP
+\fBmkimage\fP(1)
+
+.SH "AUTHORS"
+
+Daniel Stodden <daniel.stodden@gmail.com>
+.br
+Luka Perkov <uboot@lukaperkov.net>
+.br
+David Purdy <david.c.purdy@gmail.com>
diff --git a/tools/Makefile b/tools/Makefile
index 8993fdd..8097d95 100644
--- a/tools/Makefile
+++ b/tools/Makefile
@@ -72,6 +72,7 @@ BIN_FILES-$(CONFIG_SMDK5250) += mksmdk5250spl$(SFX)
 BIN_FILES-$(CONFIG_MX28) += mxsboot$(SFX)
 BIN_FILES-$(CONFIG_NETCONSOLE) += ncb$(SFX)
 BIN_FILES-$(CONFIG_SHA1_CHECK_UB_IMG) += ubsha1$(SFX)
+BIN_FILES-$(CONFIG_KIRKWOOD) += kwboot$(SFX)
 
 # Source files which exist outside the tools directory
 EXT_OBJ_FILES-$(CONFIG_BUILD_ENVCRC) += common/env_embedded.o
@@ -101,6 +102,7 @@ OBJ_FILES-$(CONFIG_NETCONSOLE) += ncb.o
 NOPED_OBJ_FILES-y += os_support.o
 OBJ_FILES-$(CONFIG_SHA1_CHECK_UB_IMG) += ubsha1.o
 NOPED_OBJ_FILES-y += ublimage.o
+OBJ_FILES-$(CONFIG_KIRKWOOD) += kwboot.o
 
 # Don't build by default
 #ifeq ($(ARCH),ppc)
@@ -234,6 +236,10 @@ $(obj)ncb$(SFX):	$(obj)ncb.o
 $(obj)ubsha1$(SFX):	$(obj)os_support.o $(obj)sha1.o $(obj)ubsha1.o
 	$(HOSTCC) $(HOSTCFLAGS) $(HOSTLDFLAGS) -o $@ $^
 
+$(obj)kwboot$(SFX): $(obj)kwboot.o
+	$(HOSTCC) $(HOSTCFLAGS) $(HOSTLDFLAGS) -o $@ $^
+	$(HOSTSTRIP) $@
+
 # Some of the tool objects need to be accessed from outside the tools directory
 $(obj)%.o: $(SRCTREE)/common/%.c
 	$(HOSTCC) -g $(HOSTCFLAGS_NOPED) -c -o $@ $<
diff --git a/tools/kwboot.c b/tools/kwboot.c
new file mode 100644
index 0000000..e773f01
--- /dev/null
+++ b/tools/kwboot.c
@@ -0,0 +1,742 @@
+/*
+ * Boot a Marvell Kirkwood SoC, with Xmodem over UART0.
+ *
+ * (c) 2012 Daniel Stodden <daniel.stodden@gmail.com>
+ *
+ * References: marvell.com, "88F6180, 88F6190, 88F6192, and 88F6281
+ *   Integrated Controller: Functional Specifications" December 2,
+ *   2008. Chapter 24.2 "BootROM Firmware".
+ */
+
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include <stdarg.h>
+#include <libgen.h>
+#include <fcntl.h>
+#include <errno.h>
+#include <unistd.h>
+#include <stdint.h>
+#include <termios.h>
+#include <sys/mman.h>
+#include <sys/stat.h>
+
+#include "kwbimage.h"
+
+#ifdef __GNUC__
+#define PACKED __attribute((packed))
+#else
+#define PACKED
+#endif
+
+/*
+ * Marvell BootROM UART Sensing
+ */
+
+static unsigned char kwboot_msg_boot[] = {
+	0xBB, 0x11, 0x22, 0x33, 0x44, 0x55, 0x66, 0x77
+};
+
+#define KWBOOT_MSG_REQ_DELAY	10 /* ms */
+#define KWBOOT_MSG_RSP_TIMEO	50 /* ms */
+
+/*
+ * Xmodem Transfers
+ */
+
+#define SOH	1	/* sender start of block header */
+#define EOT	4	/* sender end of block transfer */
+#define ACK	6	/* target block ack */
+#define NAK	21	/* target block negative ack */
+#define CAN	24	/* target/sender transfer cancellation */
+
+struct kwboot_block {
+	uint8_t soh;
+	uint8_t pnum;
+	uint8_t _pnum;
+	uint8_t data[128];
+	uint8_t csum;
+} PACKED;
+
+#define KWBOOT_BLK_RSP_TIMEO 1000 /* ms */
+
+static int kwboot_verbose;
+
+static void
+kwboot_printv(const char *fmt, ...)
+{
+	va_list ap;
+
+	if (kwboot_verbose) {
+		va_start(ap, fmt);
+		vprintf(fmt, ap);
+		va_end(ap);
+		fflush(stdout);
+	}
+}
+
+static void
+__spinner(void)
+{
+	const char seq[] = { '-', '\\', '|', '/' };
+	const int div = 8;
+	static int state, bs;
+
+	if (state % div == 0) {
+		fputc(bs, stdout);
+		fputc(seq[state / div % sizeof(seq)], stdout);
+		fflush(stdout);
+	}
+
+	bs = '\b';
+	state++;
+}
+
+static void
+kwboot_spinner(void)
+{
+	if (kwboot_verbose)
+		__spinner();
+}
+
+static void
+__progress(int pct, char c)
+{
+	const int width = 70;
+	static const char *nl = "";
+	static int pos;
+
+	if (pos % width == 0)
+		printf("%s%3d %% [", nl, pct);
+
+	fputc(c, stdout);
+
+	nl = "]\n";
+	pos++;
+
+	if (pct == 100) {
+		while (pos++ < width)
+			fputc(' ', stdout);
+		fputs(nl, stdout);
+	}
+
+	fflush(stdout);
+
+}
+
+static void
+kwboot_progress(int _pct, char c)
+{
+	static int pct;
+
+	if (_pct != -1)
+		pct = _pct;
+
+	if (kwboot_verbose)
+		__progress(pct, c);
+}
+
+static int
+kwboot_tty_recv(int fd, void *buf, size_t len, int timeo)
+{
+	int rc, nfds;
+	fd_set rfds;
+	struct timeval tv;
+	ssize_t n;
+
+	rc = -1;
+
+	FD_ZERO(&rfds);
+	FD_SET(fd, &rfds);
+
+	tv.tv_sec = 0;
+	tv.tv_usec = timeo * 1000;
+	if (tv.tv_usec > 1000000) {
+		tv.tv_sec += tv.tv_usec / 1000000;
+		tv.tv_usec %= 1000000;
+	}
+
+	do {
+		nfds = select(fd + 1, &rfds, NULL, NULL, &tv);
+		if (nfds < 0)
+			goto out;
+		if (!nfds) {
+			errno = ETIMEDOUT;
+			goto out;
+		}
+
+		n = read(fd, buf, len);
+		if (n < 0)
+			goto out;
+
+		buf = (char *)buf + n;
+		len -= n;
+	} while (len > 0);
+
+	rc = 0;
+out:
+	return rc;
+}
+
+static int
+kwboot_tty_send(int fd, const void *buf, size_t len)
+{
+	int rc;
+	ssize_t n;
+
+	rc = -1;
+
+	do {
+		n = write(fd, buf, len);
+		if (n < 0)
+			goto out;
+
+		buf = (char *)buf + n;
+		len -= n;
+	} while (len > 0);
+
+	rc = tcdrain(fd);
+out:
+	return rc;
+}
+
+static int
+kwboot_tty_send_char(int fd, unsigned char c)
+{
+	return kwboot_tty_send(fd, &c, 1);
+}
+
+static speed_t
+kwboot_tty_speed(int baudrate)
+{
+	switch (baudrate) {
+	case 115200:
+		return B115200;
+	case 57600:
+		return B57600;
+	case 38400:
+		return B38400;
+	case 19200:
+		return B19200;
+	case 9600:
+		return B9600;
+	}
+
+	return -1;
+}
+
+static int
+kwboot_open_tty(const char *path, speed_t speed)
+{
+	int rc, fd;
+	struct termios tio;
+
+	rc = -1;
+
+	fd = open(path, O_RDWR|O_NOCTTY|O_NDELAY);
+	if (fd < 0)
+		goto out;
+
+	memset(&tio, 0, sizeof(tio));
+
+	tio.c_iflag = 0;
+	tio.c_cflag = CREAD|CLOCAL|CS8;
+
+	tio.c_cc[VMIN] = 1;
+	tio.c_cc[VTIME] = 10;
+
+	cfsetospeed(&tio, speed);
+	cfsetispeed(&tio, speed);
+
+	rc = tcsetattr(fd, TCSANOW, &tio);
+	if (rc)
+		goto out;
+
+	rc = fd;
+out:
+	if (rc < 0) {
+		if (fd >= 0)
+			close(fd);
+	}
+
+	return rc;
+}
+
+static int
+kwboot_bootmsg(int tty, void *msg)
+{
+	int rc;
+	char c;
+
+	kwboot_printv("Sending boot message. Please reboot the target...");
+
+	do {
+		rc = tcflush(tty, TCIOFLUSH);
+		if (rc)
+			break;
+
+		rc = kwboot_tty_send(tty, msg, 8);
+		if (rc) {
+			usleep(KWBOOT_MSG_REQ_DELAY * 1000);
+			continue;
+		}
+
+		rc = kwboot_tty_recv(tty, &c, 1, KWBOOT_MSG_RSP_TIMEO);
+
+		kwboot_spinner();
+
+	} while (rc || c != NAK);
+
+	kwboot_printv("\n");
+
+	return rc;
+}
+
+static int
+kwboot_xm_makeblock(struct kwboot_block *block, const void *data,
+		    size_t size, int pnum)
+{
+	const size_t blksz = sizeof(block->data);
+	size_t n;
+	int i;
+
+	block->pnum = pnum;
+	block->_pnum = ~block->pnum;
+
+	n = size < blksz ? size : blksz;
+	memcpy(&block->data[0], data, n);
+	memset(&block->data[n], 0, blksz - n);
+
+	block->csum = 0;
+	for (i = 0; i < n; i++)
+		block->csum += block->data[i];
+
+	return n;
+}
+
+static int
+kwboot_xm_sendblock(int fd, struct kwboot_block *block)
+{
+	int rc, retries;
+	char c;
+
+	retries = 16;
+	do {
+		rc = kwboot_tty_send(fd, block, sizeof(*block));
+		if (rc)
+			break;
+
+		rc = kwboot_tty_recv(fd, &c, 1, KWBOOT_BLK_RSP_TIMEO);
+		if (rc)
+			break;
+
+		if (c != ACK)
+			kwboot_progress(-1, '+');
+
+	} while (c == NAK && retries-- > 0);
+
+	rc = -1;
+
+	switch (c) {
+	case ACK:
+		rc = 0;
+		break;
+	case NAK:
+		errno = EBADMSG;
+		break;
+	case CAN:
+		errno = ECANCELED;
+		break;
+	default:
+		errno = EPROTO;
+		break;
+	}
+
+	return rc;
+}
+
+static int
+kwboot_xmodem(int tty, const void *_data, size_t size)
+{
+	const uint8_t *data = _data;
+	int rc, pnum, N, err;
+
+	pnum = 1;
+	N = 0;
+
+	kwboot_printv("Sending boot image...\n");
+
+	do {
+		struct kwboot_block block;
+		int n;
+
+		n = kwboot_xm_makeblock(&block,
+					data + N, size - N,
+					pnum++);
+		if (n < 0)
+			goto can;
+
+		if (!n)
+			break;
+
+		rc = kwboot_xm_sendblock(tty, &block);
+		if (rc)
+			goto out;
+
+		N += n;
+		kwboot_progress(N * 100 / size, '.');
+	} while (1);
+
+	rc = kwboot_tty_send_char(tty, EOT);
+
+out:
+	return rc;
+
+can:
+	err = errno;
+	kwboot_tty_send_char(tty, CAN);
+	errno = err;
+	goto out;
+}
+
+static int
+kwboot_term_pipe(int in, int out, char *quit, int *s)
+{
+	ssize_t nin, nout;
+	char _buf[128], *buf = _buf;
+
+	nin = read(in, buf, sizeof(buf));
+	if (nin < 0)
+		return -1;
+
+	if (quit) {
+		int i;
+
+		for (i = 0; i < nin; i++) {
+			if (*buf == quit[*s]) {
+				(*s)++;
+				if (!quit[*s])
+					return 0;
+				buf++;
+				nin--;
+			} else
+				while (*s > 0) {
+					nout = write(out, quit, *s);
+					if (nout <= 0)
+						return -1;
+					(*s) -= nout;
+				}
+		}
+	}
+
+	while (nin > 0) {
+		nout = write(out, buf, nin);
+		if (nout <= 0)
+			return -1;
+		nin -= nout;
+	}
+
+	return 0;
+}
+
+static int
+kwboot_terminal(int tty)
+{
+	int rc, in, s;
+	char *quit = "\34c";
+	struct termios otio, tio;
+
+	rc = -1;
+
+	in = STDIN_FILENO;
+	if (isatty(in)) {
+		rc = tcgetattr(in, &otio);
+		if (!rc) {
+			tio = otio;
+			cfmakeraw(&tio);
+			rc = tcsetattr(in, TCSANOW, &tio);
+		}
+		if (rc) {
+			perror("tcsetattr");
+			goto out;
+		}
+
+		kwboot_printv("[Type Ctrl-%c + %c to quit]\r\n",
+			      quit[0]|0100, quit[1]);
+	} else
+		in = -1;
+
+	rc = 0;
+	s = 0;
+
+	do {
+		fd_set rfds;
+		int nfds = 0;
+
+		FD_SET(tty, &rfds);
+		nfds = nfds < tty ? tty : nfds;
+
+		if (in >= 0) {
+			FD_SET(in, &rfds);
+			nfds = nfds < in ? in : nfds;
+		}
+
+		nfds = select(nfds + 1, &rfds, NULL, NULL, NULL);
+		if (nfds < 0)
+			break;
+
+		if (FD_ISSET(tty, &rfds)) {
+			rc = kwboot_term_pipe(tty, STDOUT_FILENO, NULL, NULL);
+			if (rc)
+				break;
+		}
+
+		if (FD_ISSET(in, &rfds)) {
+			rc = kwboot_term_pipe(in, tty, quit, &s);
+			if (rc)
+				break;
+		}
+	} while (quit[s] != 0);
+
+	tcsetattr(in, TCSANOW, &otio);
+out:
+	return rc;
+}
+
+static void *
+kwboot_mmap_image(const char *path, size_t *size, int prot)
+{
+	int rc, fd, flags;
+	struct stat st;
+	void *img;
+
+	rc = -1;
+	fd = -1;
+	img = NULL;
+
+	fd = open(path, O_RDONLY);
+	if (fd < 0)
+		goto out;
+
+	rc = fstat(fd, &st);
+	if (rc)
+		goto out;
+
+	flags = (prot & PROT_WRITE) ? MAP_PRIVATE : MAP_SHARED;
+
+	img = mmap(NULL, st.st_size, prot, flags, fd, 0);
+	if (img == MAP_FAILED) {
+		img = NULL;
+		goto out;
+	}
+
+	rc = 0;
+	*size = st.st_size;
+out:
+	if (rc && img) {
+		munmap(img, st.st_size);
+		img = NULL;
+	}
+	if (fd >= 0)
+		close(fd);
+
+	return img;
+}
+
+static uint8_t
+kwboot_img_csum8(void *_data, size_t size)
+{
+	uint8_t *data = _data, csum;
+
+	for (csum = 0; size-- > 0; data++)
+		csum += *data;
+
+	return csum;
+}
+
+static int
+kwboot_img_patch_hdr(void *img, size_t size)
+{
+	int rc;
+	bhr_t *hdr;
+	uint8_t csum;
+	const size_t hdrsz = sizeof(*hdr);
+
+	rc = -1;
+	hdr = img;
+
+	if (size < hdrsz) {
+		errno = EINVAL;
+		goto out;
+	}
+
+	csum = kwboot_img_csum8(hdr, hdrsz) - hdr->checkSum;
+	if (csum != hdr->checkSum) {
+		errno = EINVAL;
+		goto out;
+	}
+
+	if (hdr->blockid == IBR_HDR_UART_ID) {
+		rc = 0;
+		goto out;
+	}
+
+	hdr->blockid = IBR_HDR_UART_ID;
+
+	hdr->nandeccmode = IBR_HDR_ECC_DISABLED;
+	hdr->nandpagesize = 0;
+
+	hdr->srcaddr = hdr->ext
+		? sizeof(struct kwb_header)
+		: sizeof(*hdr);
+
+	hdr->checkSum = kwboot_img_csum8(hdr, hdrsz) - csum;
+
+	rc = 0;
+out:
+	return rc;
+}
+
+static void
+kwboot_usage(FILE *stream, char *progname)
+{
+	fprintf(stream,
+		"Usage: %s -b <image> [ -p ] [ -t ] "
+		"[-B <baud> ] <TTY>\n", progname);
+	fprintf(stream, "\n");
+	fprintf(stream, "  -b <image>: boot <image>\n");
+	fprintf(stream, "  -p: patch <image> to type 0x69 (uart boot)\n");
+	fprintf(stream, "\n");
+	fprintf(stream, "  -t: mini terminal\n");
+	fprintf(stream, "\n");
+	fprintf(stream, "  -B <baud>: set baud rate\n");
+	fprintf(stream, "\n");
+}
+
+int
+main(int argc, char **argv)
+{
+	const char *ttypath, *imgpath;
+	int rv, rc, tty, term, prot, patch;
+	void *bootmsg;
+	void *img;
+	size_t size;
+	speed_t speed;
+
+	rv = 1;
+	tty = -1;
+	bootmsg = NULL;
+	imgpath = NULL;
+	img = NULL;
+	term = 0;
+	patch = 0;
+	size = 0;
+	speed = B115200;
+
+	kwboot_verbose = isatty(STDOUT_FILENO);
+
+	do {
+		int c = getopt(argc, argv, "hb:ptB:");
+		if (c < 0)
+			break;
+
+		switch (c) {
+		case 'b':
+			bootmsg = kwboot_msg_boot;
+			imgpath = optarg;
+			break;
+
+		case 'p':
+			patch = 1;
+			break;
+
+		case 't':
+			term = 1;
+			break;
+
+		case 'B':
+			speed = kwboot_tty_speed(atoi(optarg));
+			if (speed == -1)
+				goto usage;
+			break;
+
+		case 'h':
+			rv = 0;
+		default:
+			goto usage;
+		}
+	} while (1);
+
+	if (!bootmsg && !term)
+		goto usage;
+
+	if (patch && !imgpath)
+		goto usage;
+
+	if (argc - optind < 1)
+		goto usage;
+
+	ttypath = argv[optind++];
+
+	tty = kwboot_open_tty(ttypath, speed);
+	if (tty < 0) {
+		perror(ttypath);
+		goto out;
+	}
+
+	if (imgpath) {
+		prot = PROT_READ | (patch ? PROT_WRITE : 0);
+
+		img = kwboot_mmap_image(imgpath, &size, prot);
+		if (!img) {
+			perror(imgpath);
+			goto out;
+		}
+	}
+
+	if (patch) {
+		rc = kwboot_img_patch_hdr(img, size);
+		if (rc) {
+			fprintf(stderr, "%s: Invalid image.\n", imgpath);
+			goto out;
+		}
+	}
+
+	if (bootmsg) {
+		rc = kwboot_bootmsg(tty, bootmsg);
+		if (rc) {
+			perror("bootmsg");
+			goto out;
+		}
+	}
+
+	if (img) {
+		rc = kwboot_xmodem(tty, img, size);
+		if (rc) {
+			perror("xmodem");
+			goto out;
+		}
+	}
+
+	if (term) {
+		rc = kwboot_terminal(tty);
+		if (rc && !(errno == EINTR)) {
+			perror("terminal");
+			goto out;
+		}
+	}
+
+	rv = 0;
+out:
+	if (tty >= 0)
+		close(tty);
+
+	if (img)
+		munmap(img, size);
+
+	return rv;
+
+usage:
+	kwboot_usage(rv ? stderr : stdout, basename(argv[0]));
+	goto out;
+}
