/*
 * Boot a Marvell SoC, with Xmodem over UART0.
 *  supports Kirkwood, Dove, Avanta, Armada 370, Armada XP, Armada 375,
 *           Armada 38x and Armada 39x.
 *
 * (c) 2012 Daniel Stodden <daniel.stodden@gmail.com>
 * (c) 2021 Pali Rohár <pali@kernel.org>
 * (c) 2021 Marek Behún <marek.behun@nic.cz>
 *
 * References:
 * - "88F6180, 88F6190, 88F6192, and 88F6281: Integrated Controller: Functional
 *   Specifications" December 2, 2008. Chapter 24.2 "BootROM Firmware".
 *   https://web.archive.org/web/20130730091033/https://www.marvell.com/embedded-processors/kirkwood/assets/FS_88F6180_9x_6281_OpenSource.pdf
 * - "88AP510: High-Performance SoC with Integrated CPU, 2D/3D Graphics
 *   Processor, and High-Definition Video Decoder: Functional Specifications"
 *   August 3, 2011. Chapter 5 "BootROM Firmware"
 *   https://web.archive.org/web/20120130172443/https://www.marvell.com/application-processors/armada-500/assets/Armada-510-Functional-Spec.pdf
 * - "88F6710, 88F6707, and 88F6W11: ARMADA(R) 370 SoC: Functional Specifications"
 *   May 26, 2014. Chapter 6 "BootROM Firmware".
 *   https://web.archive.org/web/20140617183701/https://www.marvell.com/embedded-processors/armada-300/assets/ARMADA370-FunctionalSpec-datasheet.pdf
 * - "MV78230, MV78260, and MV78460: ARMADA(R) XP Family of Highly Integrated
 *   Multi-Core ARMv7 Based SoC Processors: Functional Specifications"
 *   May 29, 2014. Chapter 6 "BootROM Firmware".
 *   https://web.archive.org/web/20180829171131/https://www.marvell.com/embedded-processors/armada-xp/assets/ARMADA-XP-Functional-SpecDatasheet.pdf
 * - "ARMADA(R) 375 Value-Performance Dual Core CPU System on Chip: Functional
 *   Specifications" Doc. No. MV-S109377-00, Rev. A. September 18, 2013.
 *   Chapter 7 "Boot Sequence"
 *   CONFIDENTIAL, no public documentation available
 * - "88F6810, 88F6811, 88F6821, 88F6W21, 88F6820, and 88F6828: ARMADA(R) 38x
 *   Family High-Performance Single/Dual CPU System on Chip: Functional
 *   Specifications" Doc. No. MV-S109094-00, Rev. C. August 2, 2015.
 *   Chapter 7 "Boot Flow"
 *   CONFIDENTIAL, no public documentation available
 * - "88F6920, 88F6925 and 88F6928: ARMADA(R) 39x High-Performance Dual Core CPU
 *   System on Chip Functional Specifications" Doc. No. MV-S109896-00, Rev. B.
 *   December 22, 2015. Chapter 7 "Boot Flow"
 *   CONFIDENTIAL, no public documentation available
 */

#include "kwbimage.h"
#include "mkimage.h"
#include "version.h"

#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <stdarg.h>
#include <image.h>
#include <libgen.h>
#include <fcntl.h>
#include <errno.h>
#include <unistd.h>
#include <stdint.h>
#include <time.h>
#include <sys/stat.h>
#include <pthread.h>

#ifdef __linux__
#include "termios_linux.h"
#else
#include <termios.h>
#endif

/*
 * These functions are in <term.h> header file, but this header file conflicts
 * with "termios_linux.h" header file. So declare these functions manually.
 */
extern int setupterm(const char *, int, int *);
extern char *tigetstr(const char *);

/*
 * Marvell BootROM UART Sensing
 */

static unsigned char kwboot_msg_boot[] = {
        0xBB, 0x11, 0x22, 0x33, 0x44, 0x55, 0x66, 0x77
};

static unsigned char kwboot_msg_debug[] = {
        0xDD, 0x11, 0x22, 0x33, 0x44, 0x55, 0x66, 0x77
};

/* Defines known to work on Kirkwood */
#define KWBOOT_MSG_RSP_TIMEO    50 /* ms */

/* Defines known to work on Armada XP */
#define KWBOOT_MSG_RSP_TIMEO_AXP        1000 /* 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 KWBOOT_XM_BLKSZ 128 /* xmodem block size */

struct kwboot_block {
        uint8_t soh;
        uint8_t pnum;
        uint8_t _pnum;
        uint8_t data[KWBOOT_XM_BLKSZ];
        uint8_t csum;
} __packed;

#define KWBOOT_BLK_RSP_TIMEO 2000 /* ms */
#define KWBOOT_HDR_RSP_TIMEO 10000 /* ms */

/* ARM code to change baudrate */
static unsigned char kwboot_baud_code[] = {
                                /* ; #define UART_BASE 0xd0012000             */
                                /* ; #define DLL       0x00                   */
                                /* ; #define DLH       0x04                   */
                                /* ; #define LCR       0x0c                   */
                                /* ; #define   DLAB    0x80                   */
                                /* ; #define LSR       0x14                   */
                                /* ; #define   TEMT    0x40                   */
                                /* ; #define DIV_ROUND(a, b) ((a + b/2) / b)  */
                                /* ;                                          */
                                /* ; u32 set_baudrate(u32 old_b, u32 new_b) { */
                                /* ;   while                                  */
                                /* ;      (!(readl(UART_BASE + LSR) & TEMT)); */
                                /* ;   u32 lcr = readl(UART_BASE + LCR);      */
                                /* ;   writel(UART_BASE + LCR, lcr | DLAB);   */
                                /* ;   u8 old_dll = readl(UART_BASE + DLL);   */
                                /* ;   u8 old_dlh = readl(UART_BASE + DLH);   */
                                /* ;   u16 old_dl = old_dll | (old_dlh << 8); */
                                /* ;   u32 clk = old_b * old_dl;              */
                                /* ;   u16 new_dl = DIV_ROUND(clk, new_b);    */
                                /* ;   u8 new_dll = new_dl & 0xff;            */
                                /* ;   u8 new_dlh = (new_dl >> 8) & 0xff;     */
                                /* ;   writel(UART_BASE + DLL, new_dll);      */
                                /* ;   writel(UART_BASE + DLH, new_dlh);      */
                                /* ;   writel(UART_BASE + LCR, lcr & ~DLAB);  */
                                /* ;   msleep(5);                             */
                                /* ;   return 0;                              */
                                /* ; }                                        */

                                /*  ; r0 = UART_BASE                          */
        0x0d, 0x02, 0xa0, 0xe3, /* mov   r0, #0xd0000000                      */
        0x12, 0x0a, 0x80, 0xe3, /* orr   r0, r0, #0x12000                     */

                                /*  ; Wait until Transmitter FIFO is Empty    */
                                /* .Lloop_txempty:                            */
                                /*  ; r1 = UART_BASE[LSR] & TEMT              */
        0x14, 0x10, 0x90, 0xe5, /* ldr   r1, [r0, #0x14]                      */
        0x40, 0x00, 0x11, 0xe3, /* tst   r1, #0x40                            */
        0xfc, 0xff, 0xff, 0x0a, /* beq   .Lloop_txempty                       */

                                /*  ; Set Divisor Latch Access Bit            */
                                /*  ; UART_BASE[LCR] |= DLAB                  */
        0x0c, 0x10, 0x90, 0xe5, /* ldr   r1, [r0, #0x0c]                      */
        0x80, 0x10, 0x81, 0xe3, /* orr   r1, r1, #0x80                        */
        0x0c, 0x10, 0x80, 0xe5, /* str   r1, [r0, #0x0c]                      */

                                /*  ; Read current Divisor Latch              */
                                /*  ; r1 = UART_BASE[DLH]<<8 | UART_BASE[DLL] */
        0x00, 0x10, 0x90, 0xe5, /* ldr   r1, [r0, #0x00]                      */
        0xff, 0x10, 0x01, 0xe2, /* and   r1, r1, #0xff                        */
        0x01, 0x20, 0xa0, 0xe1, /* mov   r2, r1                               */
        0x04, 0x10, 0x90, 0xe5, /* ldr   r1, [r0, #0x04]                      */
        0xff, 0x10, 0x01, 0xe2, /* and   r1, r1, #0xff                        */
        0x41, 0x14, 0xa0, 0xe1, /* asr   r1, r1, #8                           */
        0x02, 0x10, 0x81, 0xe1, /* orr   r1, r1, r2                           */

                                /*  ; Read old baudrate value                 */
                                /*  ; r2 = old_baudrate                       */
        0x74, 0x20, 0x9f, 0xe5, /* ldr   r2, old_baudrate                     */

                                /*  ; Calculate base clock                    */
                                /*  ; r1 = r2 * r1                            */
        0x92, 0x01, 0x01, 0xe0, /* mul   r1, r2, r1                           */

                                /*  ; Read new baudrate value                 */
                                /*  ; r2 = new_baudrate                       */
        0x70, 0x20, 0x9f, 0xe5, /* ldr   r2, new_baudrate                     */

                                /*  ; Calculate new Divisor Latch             */
                                /*  ; r1 = DIV_ROUND(r1, r2) =                */
                                /*  ;    = (r1 + r2/2) / r2                   */
        0xa2, 0x10, 0x81, 0xe0, /* add   r1, r1, r2, lsr #1                   */
        0x02, 0x40, 0xa0, 0xe1, /* mov   r4, r2                               */
        0xa1, 0x00, 0x54, 0xe1, /* cmp   r4, r1, lsr #1                       */
                                /* .Lloop_div1:                               */
        0x84, 0x40, 0xa0, 0x91, /* movls r4, r4, lsl #1                       */
        0xa1, 0x00, 0x54, 0xe1, /* cmp   r4, r1, lsr #1                       */
        0xfc, 0xff, 0xff, 0x9a, /* bls   .Lloop_div1                          */
        0x00, 0x30, 0xa0, 0xe3, /* mov   r3, #0                               */
                                /* .Lloop_div2:                               */
        0x04, 0x00, 0x51, 0xe1, /* cmp   r1, r4                               */
        0x04, 0x10, 0x41, 0x20, /* subhs r1, r1, r4                           */
        0x03, 0x30, 0xa3, 0xe0, /* adc   r3, r3, r3                           */
        0xa4, 0x40, 0xa0, 0xe1, /* mov   r4, r4, lsr #1                       */
        0x02, 0x00, 0x54, 0xe1, /* cmp   r4, r2                               */
        0xf9, 0xff, 0xff, 0x2a, /* bhs   .Lloop_div2                          */
        0x03, 0x10, 0xa0, 0xe1, /* mov   r1, r3                               */

                                /*  ; Set new Divisor Latch Low               */
                                /*  ; UART_BASE[DLL] = r1 & 0xff              */
        0x01, 0x20, 0xa0, 0xe1, /* mov   r2, r1                               */
        0xff, 0x20, 0x02, 0xe2, /* and   r2, r2, #0xff                        */
        0x00, 0x20, 0x80, 0xe5, /* str   r2, [r0, #0x00]                      */

                                /*  ; Set new Divisor Latch High              */
                                /*  ; UART_BASE[DLH] = r1>>8 & 0xff           */
        0x41, 0x24, 0xa0, 0xe1, /* asr   r2, r1, #8                           */
        0xff, 0x20, 0x02, 0xe2, /* and   r2, r2, #0xff                        */
        0x04, 0x20, 0x80, 0xe5, /* str   r2, [r0, #0x04]                      */

                                /*  ; Clear Divisor Latch Access Bit          */
                                /*  ; UART_BASE[LCR] &= ~DLAB                 */
        0x0c, 0x10, 0x90, 0xe5, /* ldr   r1, [r0, #0x0c]                      */
        0x80, 0x10, 0xc1, 0xe3, /* bic   r1, r1, #0x80                        */
        0x0c, 0x10, 0x80, 0xe5, /* str   r1, [r0, #0x0c]                      */

                                /*  ; Loop 0x2dc000 (2998272) cycles          */
                                /*  ; which is about 5ms on 1200 MHz CPU      */
                                /*  ; r1 = 0x2dc000                           */
        0xb7, 0x19, 0xa0, 0xe3, /* mov   r1, #0x2dc000                        */
                                /* .Lloop_sleep:                              */
        0x01, 0x10, 0x41, 0xe2, /* sub   r1, r1, #1                           */
        0x00, 0x00, 0x51, 0xe3, /* cmp   r1, #0                               */
        0xfc, 0xff, 0xff, 0x1a, /* bne   .Lloop_sleep                         */

                                /*  ; Jump to the end of execution            */
        0x01, 0x00, 0x00, 0xea, /* b     end                                  */

                                /*  ; Placeholder for old baudrate value      */
                                /* old_baudrate:                              */
        0x00, 0x00, 0x00, 0x00, /* .word 0                                    */

                                /*  ; Placeholder for new baudrate value      */
                                /* new_baudrate:                              */
        0x00, 0x00, 0x00, 0x00, /* .word 0                                    */

                                /* end:                                       */
};

/* ARM code from binary header executed by BootROM before changing baudrate */
static unsigned char kwboot_baud_code_binhdr_pre[] = {
                                /* ; #define UART_BASE 0xd0012000             */
                                /* ; #define THR       0x00                   */
                                /* ; #define LSR       0x14                   */
                                /* ; #define   THRE    0x20                   */
                                /* ;                                          */
                                /* ; void send_preamble(void) {               */
                                /* ;   const u8 *str = "$baudratechange";     */
                                /* ;   u8 c;                                  */
                                /* ;   do {                                   */
                                /* ;       while                              */
                                /* ;       ((readl(UART_BASE + LSR) & THRE)); */
                                /* ;       c = *str++;                        */
                                /* ;       writel(UART_BASE + THR, c);        */
                                /* ;   } while (c);                           */
                                /* ; }                                        */

                                /*  ; Preserve registers for BootROM          */
        0xfe, 0x5f, 0x2d, 0xe9, /* push  { r1 - r12, lr }                     */

                                /*  ; r0 = UART_BASE                          */
        0x0d, 0x02, 0xa0, 0xe3, /* mov   r0, #0xd0000000                      */
        0x12, 0x0a, 0x80, 0xe3, /* orr   r0, r0, #0x12000                     */

                                /*  ; r2 = address of preamble string         */
        0x00, 0x20, 0x8f, 0xe2, /* adr   r2, .Lstr_preamble                   */

                                /*  ; Skip preamble data section              */
        0x03, 0x00, 0x00, 0xea, /* b     .Lloop_preamble                      */

                                /*  ; Preamble string                         */
                                /* .Lstr_preamble:                            */
        0x24, 0x62, 0x61, 0x75, /* .asciz "$baudratechange"                   */
        0x64, 0x72, 0x61, 0x74,
        0x65, 0x63, 0x68, 0x61,
        0x6e, 0x67, 0x65, 0x00,

                                /*  ; Send preamble string over UART          */
                                /* .Lloop_preamble:                           */
                                /*                                            */
                                /*  ; Wait until Transmitter Holding is Empty */
                                /* .Lloop_thre:                               */
                                /*  ; r1 = UART_BASE[LSR] & THRE              */
        0x14, 0x10, 0x90, 0xe5, /* ldr   r1, [r0, #0x14]                      */
        0x20, 0x00, 0x11, 0xe3, /* tst   r1, #0x20                            */
        0xfc, 0xff, 0xff, 0x0a, /* beq   .Lloop_thre                          */

                                /*  ; Put character into Transmitter FIFO     */
                                /*  ; r1 = *r2++                              */
        0x01, 0x10, 0xd2, 0xe4, /* ldrb  r1, [r2], #1                         */
                                /*  ; UART_BASE[THR] = r1                     */
        0x00, 0x10, 0x80, 0xe5, /* str   r1, [r0, #0x0]                       */

                                /*  ; Loop until end of preamble string       */
        0x00, 0x00, 0x51, 0xe3, /* cmp   r1, #0                               */
        0xf8, 0xff, 0xff, 0x1a, /* bne   .Lloop_preamble                      */
};

/* ARM code for returning from binary header back to BootROM */
static unsigned char kwboot_baud_code_binhdr_post[] = {
                                /*  ; Return 0 - no error                     */
        0x00, 0x00, 0xa0, 0xe3, /* mov   r0, #0                               */
        0xfe, 0x9f, 0xbd, 0xe8, /* pop   { r1 - r12, pc }                     */
};

/* ARM code for jumping to the original image exec_addr */
static unsigned char kwboot_baud_code_data_jump[] = {
        0x04, 0xf0, 0x1f, 0xe5, /* ldr   pc, exec_addr                        */
                                /*  ; Placeholder for exec_addr               */
                                /* exec_addr:                                 */
        0x00, 0x00, 0x00, 0x00, /* .word 0                                    */
};

static const char kwb_baud_magic[16] = "$baudratechange";

static int kwboot_verbose;

static int msg_rsp_timeo = KWBOOT_MSG_RSP_TIMEO;
static int blk_rsp_timeo = KWBOOT_BLK_RSP_TIMEO;

static ssize_t
kwboot_write(int fd, const char *buf, size_t len)
{
        ssize_t tot = 0;

        while (tot < len) {
                ssize_t wr = write(fd, buf + tot, len - tot);

                if (wr < 0 && errno == EINTR)
                        continue;
                else if (wr < 0)
                        return wr;

                tot += wr;
        }

        return tot;
}

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 = (pos + 1) % width;

        if (pct == 100) {
                while (pos && pos++ < width)
                        fputc(' ', stdout);
                fputs(nl, stdout);
                nl = "";
                pos = 0;
        }

        fflush(stdout);

}

static void
kwboot_progress(int _pct, char c)
{
        static int pct;

        if (_pct != -1)
                pct = _pct;

        if (kwboot_verbose)
                __progress(pct, c);

        if (pct == 100)
                pct = 0;
}

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 && errno == EINTR)
                        continue;
                else if (nfds < 0)
                        goto out;
                else if (!nfds) {
                        errno = ETIMEDOUT;
                        goto out;
                }

                n = read(fd, buf, len);
                if (n < 0 && errno == EINTR)
                        continue;
                else 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 nodrain)
{
        if (!buf)
                return 0;

        if (kwboot_write(fd, buf, len) < 0)
                return -1;

        if (nodrain)
                return 0;

        return tcdrain(fd);
}

static int
kwboot_tty_send_char(int fd, unsigned char c)
{
        return kwboot_tty_send(fd, &c, 1, 0);
}

static speed_t
kwboot_tty_baudrate_to_speed(int baudrate)
{
        switch (baudrate) {
#ifdef B4000000
        case 4000000:
                return B4000000;
#endif
#ifdef B3500000
        case 3500000:
                return B3500000;
#endif
#ifdef B3000000
        case 3000000:
                return B3000000;
#endif
#ifdef B2500000
        case 2500000:
                return B2500000;
#endif
#ifdef B2000000
        case 2000000:
                return B2000000;
#endif
#ifdef B1500000
        case 1500000:
                return B1500000;
#endif
#ifdef B1152000
        case 1152000:
                return B1152000;
#endif
#ifdef B1000000
        case 1000000:
                return B1000000;
#endif
#ifdef B921600
        case 921600:
                return B921600;
#endif
#ifdef B614400
        case 614400:
                return B614400;
#endif
#ifdef B576000
        case 576000:
                return B576000;
#endif
#ifdef B500000
        case 500000:
                return B500000;
#endif
#ifdef B460800
        case 460800:
                return B460800;
#endif
#ifdef B307200
        case 307200:
                return B307200;
#endif
#ifdef B230400
        case 230400:
                return B230400;
#endif
#ifdef B153600
        case 153600:
                return B153600;
#endif
#ifdef B115200
        case 115200:
                return B115200;
#endif
#ifdef B76800
        case 76800:
                return B76800;
#endif
#ifdef B57600
        case 57600:
                return B57600;
#endif
#ifdef B38400
        case 38400:
                return B38400;
#endif
#ifdef B19200
        case 19200:
                return B19200;
#endif
#ifdef B9600
        case 9600:
                return B9600;
#endif
#ifdef B4800
        case 4800:
                return B4800;
#endif
#ifdef B2400
        case 2400:
                return B2400;
#endif
#ifdef B1800
        case 1800:
                return B1800;
#endif
#ifdef B1200
        case 1200:
                return B1200;
#endif
#ifdef B600
        case 600:
                return B600;
#endif
#ifdef B300
        case 300:
                return B300;
#endif
#ifdef B200
        case 200:
                return B200;
#endif
#ifdef B150
        case 150:
                return B150;
#endif
#ifdef B134
        case 134:
                return B134;
#endif
#ifdef B110
        case 110:
                return B110;
#endif
#ifdef B75
        case 75:
                return B75;
#endif
#ifdef B50
        case 50:
                return B50;
#endif
        default:
#ifdef BOTHER
                return BOTHER;
#else
                return B0;
#endif
        }
}

static int
_is_within_tolerance(int value, int reference, int tolerance)
{
        return 100 * value >= reference * (100 - tolerance) &&
               100 * value <= reference * (100 + tolerance);
}

static int
kwboot_tty_change_baudrate(int fd, int baudrate)
{
        struct termios tio;
        speed_t speed;
        int rc;

        rc = tcgetattr(fd, &tio);
        if (rc)
                return rc;

        speed = kwboot_tty_baudrate_to_speed(baudrate);
        if (speed == B0) {
                errno = EINVAL;
                return -1;
        }

#ifdef BOTHER
        if (speed == BOTHER)
                tio.c_ospeed = tio.c_ispeed = baudrate;
#endif

        rc = cfsetospeed(&tio, speed);
        if (rc)
                return rc;

        rc = cfsetispeed(&tio, speed);
        if (rc)
                return rc;

        rc = tcsetattr(fd, TCSANOW, &tio);
        if (rc)
                return rc;

        rc = tcgetattr(fd, &tio);
        if (rc)
                return rc;

        if (cfgetospeed(&tio) != speed || cfgetispeed(&tio) != speed)
                goto baud_fail;

#ifdef BOTHER
        /*
         * Check whether set baudrate is within 3% tolerance.
         * If BOTHER is defined, Linux always fills out c_ospeed / c_ispeed
         * with real values.
         */
        if (!_is_within_tolerance(tio.c_ospeed, baudrate, 3))
                goto baud_fail;

        if (!_is_within_tolerance(tio.c_ispeed, baudrate, 3))
                goto baud_fail;
#endif

        return 0;

baud_fail:
        fprintf(stderr, "Could not set baudrate to requested value\n");
        errno = EINVAL;
        return -1;
}

static int
kwboot_open_tty(const char *path, int baudrate)
{
        int rc, fd, flags;
        struct termios tio;

        rc = -1;

        fd = open(path, O_RDWR | O_NOCTTY | O_NDELAY);
        if (fd < 0)
                goto out;

        rc = tcgetattr(fd, &tio);
        if (rc)
                goto out;

        cfmakeraw(&tio);
        tio.c_cflag |= CREAD | CLOCAL;
        tio.c_cflag &= ~(CSTOPB | HUPCL | CRTSCTS);
        tio.c_cc[VMIN] = 1;
        tio.c_cc[VTIME] = 0;

        rc = tcsetattr(fd, TCSANOW, &tio);
        if (rc)
                goto out;

        flags = fcntl(fd, F_GETFL);
        if (flags < 0)
                goto out;

        rc = fcntl(fd, F_SETFL, flags & ~O_NDELAY);
        if (rc)
                goto out;

        rc = kwboot_tty_change_baudrate(fd, baudrate);
        if (rc)
                goto out;

        rc = fd;
out:
        if (rc < 0) {
                if (fd >= 0)
                        close(fd);
        }

        return rc;
}

static void *
kwboot_msg_write_handler(void *arg)
{
        int tty = *(int *)((void **)arg)[0];
        const void *msg = ((void **)arg)[1];
        int rsp_timeo = msg_rsp_timeo;
        int i, dummy_oldtype;

        /* allow to cancel this thread at any time */
        pthread_setcanceltype(PTHREAD_CANCEL_ASYNCHRONOUS, &dummy_oldtype);

        while (1) {
                /* write 128 samples of message pattern into the output queue without waiting */
                for (i = 0; i < 128; i++) {
                        if (kwboot_tty_send(tty, msg, 8, 1) < 0) {
                                perror("\nFailed to send message pattern");
                                exit(1);
                        }
                }
                /* wait until output queue is transmitted and then make pause */
                if (tcdrain(tty) < 0) {
                        perror("\nFailed to send message pattern");
                        exit(1);
                }
                /* BootROM requires pause on UART after it detects message pattern */
                usleep(rsp_timeo * 1000);
        }
}

static int
kwboot_msg_start_thread(pthread_t *thread, int *tty, void *msg)
{
        void *arg[2];
        int rc;

        arg[0] = tty;
        arg[1] = msg;
        rc = pthread_create(thread, NULL, kwboot_msg_write_handler, arg);
        if (rc) {
                errno = rc;
                return -1;
        }

        return 0;
}

static int
kwboot_msg_stop_thread(pthread_t thread)
{
        int rc;

        rc = pthread_cancel(thread);
        if (rc) {
                errno = rc;
                return -1;
        }

        rc = pthread_join(thread, NULL);
        if (rc) {
                errno = rc;
                return -1;
        }

        return 0;
}

static int
kwboot_bootmsg(int tty)
{
        struct kwboot_block block;
        pthread_t write_thread;
        int rc, err;
        char c;

        /* flush input and output queue */
        tcflush(tty, TCIOFLUSH);

        rc = kwboot_msg_start_thread(&write_thread, &tty, kwboot_msg_boot);
        if (rc) {
                perror("Failed to start write thread");
                return rc;
        }

        kwboot_printv("Sending boot message. Please reboot the target...");

        err = 0;
        while (1) {
                kwboot_spinner();

                rc = kwboot_tty_recv(tty, &c, 1, msg_rsp_timeo);
                if (rc && errno == ETIMEDOUT) {
                        continue;
                } else if (rc) {
                        err = errno;
                        break;
                }

                if (c == NAK)
                        break;
        }

        kwboot_printv("\n");

        rc = kwboot_msg_stop_thread(write_thread);
        if (rc) {
                perror("Failed to stop write thread");
                return rc;
        }

        if (err) {
                errno = err;
                perror("Failed to read response for boot message pattern");
                return -1;
        }

        /*
         * At this stage we have sent more boot message patterns and BootROM
         * (at least on Armada XP and 385) started interpreting sent bytes as
         * part of xmodem packets. If BootROM is expecting SOH byte as start of
         * a xmodem packet and it receives byte 0xff, then it throws it away and
         * sends a NAK reply to host. If BootROM does not receive any byte for
         * 2s when expecting some continuation of the xmodem packet, it throws
         * away the partially received xmodem data and sends NAK reply to host.
         *
         * Therefore for starting xmodem transfer we have two options: Either
         * wait 2s or send 132 0xff bytes (which is the size of xmodem packet)
         * to ensure that BootROM throws away any partially received data.
         */

        /* flush output queue with remaining boot message patterns */
        rc = tcflush(tty, TCOFLUSH);
        if (rc) {
                perror("Failed to flush output queue");
                return rc;
        }

        /* send one xmodem packet with 0xff bytes to force BootROM to re-sync */
        memset(&block, 0xff, sizeof(block));
        rc = kwboot_tty_send(tty, &block, sizeof(block), 0);
        if (rc) {
                perror("Failed to send sync sequence");
                return rc;
        }

        /*
         * Sending 132 bytes via 115200B/8-N-1 takes 11.45 ms, reading 132 bytes
         * takes 11.45 ms, so waiting for 30 ms should be enough.
         */
        usleep(30 * 1000);

        /* flush remaining NAK replies from input queue */
        rc = tcflush(tty, TCIFLUSH);
        if (rc) {
                perror("Failed to flush input queue");
                return rc;
        }

        return 0;
}

static int
kwboot_debugmsg(int tty)
{
        unsigned char buf[8192];
        pthread_t write_thread;
        int rc, err, i, pos;
        size_t off;

        /* flush input and output queue */
        tcflush(tty, TCIOFLUSH);

        rc = kwboot_msg_start_thread(&write_thread, &tty, kwboot_msg_debug);
        if (rc) {
                perror("Failed to start write thread");
                return rc;
        }

        kwboot_printv("Sending debug message. Please reboot the target...");
        kwboot_spinner();

        err = 0;
        off = 0;
        while (1) {
                /* Read immediately all bytes in queue without waiting */
                rc = read(tty, buf + off, sizeof(buf) - off);
                if ((rc < 0 && errno == EINTR) || rc == 0) {
                        continue;
                } else if (rc < 0) {
                        err = errno;
                        break;
                }
                off += rc - 1;

                kwboot_spinner();

                /*
                 * Check if we received at least 4 debug message patterns
                 * (console echo from BootROM) in cyclic buffer
                 */

                for (pos = 0; pos < sizeof(kwboot_msg_debug); pos++)
                        if (buf[off] == kwboot_msg_debug[(pos + off) % sizeof(kwboot_msg_debug)])
                                break;

                for (i = off; i >= 0; i--)
                        if (buf[i] != kwboot_msg_debug[(pos + i) % sizeof(kwboot_msg_debug)])
                                break;

                off -= i;

                if (off >= 4 * sizeof(kwboot_msg_debug))
                        break;

                /* If not move valid suffix from end of the buffer to the beginning of buffer */
                memmove(buf, buf + i + 1, off);
        }

        kwboot_printv("\n");

        rc = kwboot_msg_stop_thread(write_thread);
        if (rc) {
                perror("Failed to stop write thread");
                return rc;
        }

        if (err) {
                errno = err;
                perror("Failed to read response for debug message pattern");
                return -1;
        }

        /* flush output queue with remaining debug message patterns */
        rc = tcflush(tty, TCOFLUSH);
        if (rc) {
                perror("Failed to flush output queue");
                return rc;
        }

        kwboot_printv("Clearing input buffer...\n");

        /*
         * Wait until BootROM transmit all remaining echo characters.
         * Experimentally it was measured that for Armada 385 BootROM
         * it is required to wait at least 0.415s. So wait 0.5s.
         */
        usleep(500 * 1000);

        /*

         * In off variable is stored number of characters received after the
         * successful detection of echo reply. So these characters are console
         * echo for other following debug message patterns. BootROM may have in
         * its output queue other echo characters which were being transmitting
         * before above sleep call. So read remaining number of echo characters
         * sent by the BootROM now.
         */
        while ((rc = kwboot_tty_recv(tty, &buf[0], 1, 0)) == 0)
                off++;
        if (errno != ETIMEDOUT) {
                perror("Failed to read response");
                return rc;
        }

        /*
         * Clear every echo character set by the BootROM by backspace byte.
         * This is required prior writing any command to the BootROM debug
         * because BootROM command line buffer has limited size. If length
         * of the command is larger than buffer size then it looks like
         * that Armada 385 BootROM crashes after sending ENTER. So erase it.
         * Experimentally it was measured that for Armada 385 BootROM it is
         * required to send at least 3 backspace bytes for one echo character.
         * This is unknown why. But lets do it.
         */
        off *= 3;
        memset(buf, '\x08', sizeof(buf));
        while (off > sizeof(buf)) {
                rc = kwboot_tty_send(tty, buf, sizeof(buf), 1);
                if (rc) {
                        perror("Failed to send clear sequence");
                        return rc;
                }
                off -= sizeof(buf);
        }
        rc = kwboot_tty_send(tty, buf, off, 0);
        if (rc) {
                perror("Failed to send clear sequence");
                return rc;
        }

        usleep(msg_rsp_timeo * 1000);
        rc = tcflush(tty, TCIFLUSH);
        if (rc) {
                perror("Failed to flush input queue");
                return rc;
        }

        return 0;
}

static size_t
kwboot_xm_makeblock(struct kwboot_block *block, const void *data,
                    size_t size, int pnum)
{
        size_t i, n;

        block->soh = SOH;
        block->pnum = pnum;
        block->_pnum = ~block->pnum;

        n = size < KWBOOT_XM_BLKSZ ? size : KWBOOT_XM_BLKSZ;
        memcpy(&block->data[0], data, n);
        memset(&block->data[n], 0, KWBOOT_XM_BLKSZ - n);

        block->csum = 0;
        for (i = 0; i < n; i++)
                block->csum += block->data[i];

        return n;
}

static uint64_t
_now(void)
{
        struct timespec ts;

        if (clock_gettime(CLOCK_MONOTONIC, &ts)) {
                static int err_print;

                if (!err_print) {
                        perror("clock_gettime() does not work");
                        err_print = 1;
                }

                /* this will just make the timeout not work */
                return -1ULL;
        }

        return ts.tv_sec * 1000ULL + (ts.tv_nsec + 500000) / 1000000;
}

static int
_is_xm_reply(char c)
{
        return c == ACK || c == NAK;
}

static int
_xm_reply_to_error(int c)
{
        int rc = -1;

        switch (c) {
        case ACK:
                rc = 0;
                break;
        case NAK:
                errno = EBADMSG;
                break;
        default:
                errno = EPROTO;
                break;
        }

        return rc;
}

static int
kwboot_baud_magic_handle(int fd, char c, int baudrate)
{
        static size_t rcv_len;

        if (rcv_len < sizeof(kwb_baud_magic)) {
                /* try to recognize whole magic word */
                if (c == kwb_baud_magic[rcv_len]) {
                        rcv_len++;
                } else {
                        printf("%.*s%c", (int)rcv_len, kwb_baud_magic, c);
                        fflush(stdout);
                        rcv_len = 0;
                }
        }

        if (rcv_len == sizeof(kwb_baud_magic)) {
                /* magic word received */
                kwboot_printv("\nChanging baudrate to %d Bd\n", baudrate);

                return kwboot_tty_change_baudrate(fd, baudrate) ? : 1;
        } else {
                return 0;
        }
}

static int
kwboot_xm_recv_reply(int fd, char *c, int stop_on_non_xm,
                     int ignore_nak_reply,
                     int allow_non_xm, int *non_xm_print,
                     int baudrate, int *baud_changed)
{
        int timeout = allow_non_xm ? KWBOOT_HDR_RSP_TIMEO : blk_rsp_timeo;
        uint64_t recv_until = _now() + timeout;
        int rc;

        while (1) {
                rc = kwboot_tty_recv(fd, c, 1, timeout);
                if (rc) {
                        if (errno != ETIMEDOUT)
                                return rc;
                        else if (allow_non_xm && *non_xm_print)
                                return -1;
                        else
                                *c = NAK;
                }

                /* If received xmodem reply, end. */
                if (_is_xm_reply(*c)) {
                        if (*c == NAK && ignore_nak_reply) {
                                timeout = recv_until - _now();
                                if (timeout >= 0)
                                        continue;
                        }
                        break;
                }

                /*
                 * If receiving/printing non-xmodem text output is allowed and
                 * such a byte was received, we want to increase receiving time
                 * and either:
                 * - print the byte, if it is not part of baudrate change magic
                 *   sequence while baudrate change was requested (-B option)
                 * - change baudrate
                 * Otherwise decrease timeout by time elapsed.
                 */
                if (allow_non_xm) {
                        recv_until = _now() + timeout;

                        if (baudrate && !*baud_changed) {
                                rc = kwboot_baud_magic_handle(fd, *c, baudrate);
                                if (rc == 1)
                                        *baud_changed = 1;
                                else if (!rc)
                                        *non_xm_print = 1;
                                else
                                        return rc;
                        } else if (!baudrate || !*baud_changed) {
                                putchar(*c);
                                fflush(stdout);
                                *non_xm_print = 1;
                        }
                } else {
                        if (stop_on_non_xm)
                                break;
                        timeout = recv_until - _now();
                        if (timeout < 0) {
                                errno = ETIMEDOUT;
                                return -1;
                        }
                }
        }

        return 0;
}

static int
kwboot_xm_sendblock(int fd, struct kwboot_block *block, int allow_non_xm,
                    int *done_print, int baudrate, int allow_retries)
{
        int non_xm_print, baud_changed;
        int rc, err, retries;
        char c;

        *done_print = 0;
        non_xm_print = 0;
        baud_changed = 0;

        retries = 0;
        do {
                rc = kwboot_tty_send(fd, block, sizeof(*block), 1);
                if (rc)
                        goto err;

                if (allow_non_xm && !*done_print) {
                        kwboot_progress(100, '.');
                        kwboot_printv("Done\n");
                        *done_print = 1;
                }

                rc = kwboot_xm_recv_reply(fd, &c, retries < 3,
                                          retries > 8,
                                          allow_non_xm, &non_xm_print,
                                          baudrate, &baud_changed);
                if (rc)
                        goto err;

                if (!allow_non_xm && c != ACK) {
                        if (c == NAK && allow_retries && retries + 1 < 16)
                                kwboot_progress(-1, '+');
                        else
                                kwboot_progress(-1, 'E');
                }
        } while (c == NAK && allow_retries && retries++ < 16);

        if (non_xm_print)
                kwboot_printv("\n");

        if (allow_non_xm && baudrate && !baud_changed) {
                fprintf(stderr, "Baudrate was not changed\n");
                errno = EPROTO;
                return -1;
        }

        return _xm_reply_to_error(c);
err:
        err = errno;
        kwboot_printv("\n");
        errno = err;
        return rc;
}

static int
kwboot_xm_finish(int fd)
{
        int rc, retries;
        char c;

        kwboot_printv("Finishing transfer\n");

        retries = 0;
        do {
                rc = kwboot_tty_send_char(fd, EOT);
                if (rc)
                        return rc;

                rc = kwboot_xm_recv_reply(fd, &c, retries < 3,
                                          retries > 8,
                                          0, NULL, 0, NULL);
                if (rc)
                        return rc;
        } while (c == NAK && retries++ < 16);

        return _xm_reply_to_error(c);
}

static int
kwboot_xmodem_one(int tty, int *pnum, int header, const uint8_t *data,
                  size_t size, int baudrate)
{
        int done_print = 0;
        size_t sent, left;
        int rc;

        kwboot_printv("Sending boot image %s (%zu bytes)...\n",
                      header ? "header" : "data", size);

        left = size;
        sent = 0;

        while (sent < size) {
                struct kwboot_block block;
                int last_block;
                size_t blksz;

                blksz = kwboot_xm_makeblock(&block, data, left, (*pnum)++);
                data += blksz;

                last_block = (left <= blksz);

                /*
                 * Handling of repeated xmodem packets is completely broken in
                 * Armada 385 BootROM - it completely ignores xmodem packet
                 * numbers, they are only used for checksum verification.
                 * BootROM can handle a retry of the xmodem packet only during
                 * the transmission of kwbimage header and only if BootROM
                 * itself sent NAK response to previous attempt (it does it on
                 * checksum failure). During the transmission of kwbimage data
                 * part, BootROM always expects next xmodem packet, even if it
                 * sent NAK to previous attempt - there is absolutely no way to
                 * repair incorrectly transmitted xmodem packet during kwbimage
                 * data part upload. Also, if kwboot receives non-ACK/NAK
                 * response (meaning that original BootROM response was damaged
                 * on UART) there is no way to detect if BootROM accepted xmodem
                 * packet or not and no way to check if kwboot could repeat the
                 * packet or not.
                 *
                 * Stop transfer and return failure if kwboot receives unknown
                 * reply if non-xmodem reply is not allowed (for all xmodem
                 * packets except the last header packet) or when non-ACK reply
                 * is received during data part transfer.
                 */
                rc = kwboot_xm_sendblock(tty, &block, header && last_block,
                                         &done_print, baudrate, header);
                if (rc)
                        goto out;

                sent += blksz;
                left -= blksz;

                if (!done_print)
                        kwboot_progress(sent * 100 / size, '.');
        }

        if (!done_print)
                kwboot_printv("Done\n");

        return 0;
out:
        kwboot_printv("\n");
        return rc;
}

static int
kwboot_xmodem(int tty, const void *_img, size_t size, int baudrate)
{
        const uint8_t *img = _img;
        int rc, pnum;
        size_t hdrsz;

        hdrsz = kwbheader_size(img);

        /*
         * If header size is not aligned to xmodem block size (which applies
         * for all images in kwbimage v0 format) then we have to ensure that
         * the last xmodem block of header contains beginning of the data
         * followed by the header. So align header size to xmodem block size.
         */
        hdrsz += (KWBOOT_XM_BLKSZ - hdrsz % KWBOOT_XM_BLKSZ) % KWBOOT_XM_BLKSZ;

        pnum = 1;

        rc = kwboot_xmodem_one(tty, &pnum, 1, img, hdrsz, baudrate);
        if (rc)
                return rc;

        /*
         * If we have already sent image data as a part of the last
         * xmodem header block then we have nothing more to send.
         */
        if (hdrsz < size) {
                img += hdrsz;
                size -= hdrsz;
                rc = kwboot_xmodem_one(tty, &pnum, 0, img, size, 0);
                if (rc)
                        return rc;
        }

        rc = kwboot_xm_finish(tty);
        if (rc)
                return rc;

        if (baudrate) {
                kwboot_printv("\nChanging baudrate back to 115200 Bd\n\n");
                rc = kwboot_tty_change_baudrate(tty, 115200);
                if (rc)
                        return rc;
        }

        return 0;
}

static int
kwboot_term_pipe(int in, int out, const char *quit, int *s, const char *kbs, int *k)
{
        char buf[128];
        ssize_t nin, noff;

        nin = read(in, buf, sizeof(buf));
        if (nin <= 0)
                return -1;

        noff = 0;

        if (quit || kbs) {
                int i;

                for (i = 0; i < nin; i++) {
                        if ((quit || kbs) &&
                            (!quit || buf[i] != quit[*s]) &&
                            (!kbs || buf[i] != kbs[*k])) {
                                const char *prefix;
                                int plen;

                                if (quit && kbs) {
                                        prefix = (*s >= *k) ? quit : kbs;
                                        plen = (*s >= *k) ? *s : *k;
                                } else if (quit) {
                                        prefix = quit;
                                        plen = *s;
                                } else {
                                        prefix = kbs;
                                        plen = *k;
                                }

                                if (plen > i && kwboot_write(out, prefix, plen - i) < 0)
                                        return -1;
                        }

                        if (quit && buf[i] == quit[*s]) {
                                (*s)++;
                                if (!quit[*s]) {
                                        nin = (i > *s) ? (i - *s) : 0;
                                        break;
                                }
                        } else if (quit) {
                                *s = 0;
                        }

                        if (kbs && buf[i] == kbs[*k]) {
                                (*k)++;
                                if (!kbs[*k]) {
                                        if (i > *k + noff &&
                                            kwboot_write(out, buf + noff, i - *k - noff) < 0)
                                                return -1;
                                        /*
                                         * Replace backspace key by '\b' (0x08)
                                         * byte which is the only recognized
                                         * backspace byte by Marvell BootROM.
                                         */
                                        if (write(out, "\x08", 1) < 0)
                                                return -1;
                                        noff = i + 1;
                                        *k = 0;
                                }
                        } else if (kbs) {
                                *k = 0;
                        }
                }

                if (i == nin) {
                        i = 0;
                        if (quit && i < *s)
                                i = *s;
                        if (kbs && i < *k)
                                i = *k;
                        nin -= (nin > i) ? i : nin;
                }
        }

        if (nin > noff && kwboot_write(out, buf + noff, nin - noff) < 0)
                return -1;

        return 0;
}

static int
kwboot_terminal(int tty)
{
        int rc, in, s, k;
        const char *kbs = NULL;
        const 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;
                }

                /*
                 * Get sequence for backspace key used by the current
                 * terminal. Every occurrence of this sequence will be
                 * replaced by '\b' byte which is the only recognized
                 * backspace byte by Marvell BootROM.
                 *
                 * Note that we cannot read this sequence from termios
                 * c_cc[VERASE] as VERASE is valid only when ICANON is
                 * set in termios c_lflag, which is not case for us.
                 *
                 * Also most terminals do not set termios c_cc[VERASE]
                 * as c_cc[VERASE] can specify only one-byte sequence
                 * and instead let applications to read (possible
                 * multi-byte) sequence for backspace key from "kbs"
                 * terminfo database based on $TERM env variable.
                 *
                 * So read "kbs" from terminfo database via tigetstr()
                 * call after successful setupterm(). Most terminals
                 * use byte 0x7F for backspace key, so replacement with
                 * '\b' is required.
                 */
                if (setupterm(NULL, STDOUT_FILENO, &rc) == 0) {
                        kbs = tigetstr("kbs");
                        if (kbs == (char *)-1)
                                kbs = NULL;
                }

                kwboot_printv("[Type Ctrl-%c + %c to quit]\r\n",
                              quit[0] | 0100, quit[1]);
        } else
                in = -1;

        rc = 0;
        s = 0;
        k = 0;

        do {
                fd_set rfds;
                int nfds = 0;

                FD_ZERO(&rfds);
                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, NULL, NULL);
                        if (rc)
                                break;
                }

                if (in >= 0 && FD_ISSET(in, &rfds)) {
                        rc = kwboot_term_pipe(in, tty, quit, &s, kbs, &k);
                        if (rc)
                                break;
                }
        } while (quit[s] != 0);

        if (in >= 0)
                tcsetattr(in, TCSANOW, &otio);
        printf("\n");
out:
        return rc;
}

static void *
kwboot_read_image(const char *path, size_t *size, size_t reserve)
{
        int rc, fd;
        struct stat st;
        void *img;
        off_t tot;

        rc = -1;
        img = NULL;

        fd = open(path, O_RDONLY);
        if (fd < 0)
                goto out;

        rc = fstat(fd, &st);
        if (rc)
                goto out;

        img = malloc(st.st_size + reserve);
        if (!img)
                goto out;

        tot = 0;
        while (tot < st.st_size) {
                ssize_t rd = read(fd, img + tot, st.st_size - tot);

                if (rd < 0)
                        goto out;

                tot += rd;

                if (!rd && tot < st.st_size) {
                        errno = EIO;
                        goto out;
                }
        }

        rc = 0;
        *size = st.st_size;
out:
        if (rc && img) {
                free(img);
                img = NULL;
        }
        if (fd >= 0)
                close(fd);

        return img;
}

static uint8_t
kwboot_hdr_csum8(const void *hdr)
{
        const uint8_t *data = hdr;
        uint8_t csum;
        size_t size;

        size = kwbheader_size_for_csum(hdr);

        for (csum = 0; size-- > 0; data++)
                csum += *data;

        return csum;
}

static uint32_t *
kwboot_img_csum32_ptr(void *img)
{
        struct main_hdr_v1 *hdr = img;
        uint32_t datasz;

        datasz = le32_to_cpu(hdr->blocksize) - sizeof(uint32_t);

        return img + le32_to_cpu(hdr->srcaddr) + datasz;
}

static uint32_t
kwboot_img_csum32(const void *img)
{
        const struct main_hdr_v1 *hdr = img;
        uint32_t datasz, csum = 0;
        const uint32_t *data;

        datasz = le32_to_cpu(hdr->blocksize) - sizeof(csum);
        if (datasz % sizeof(uint32_t))
                return 0;

        data = img + le32_to_cpu(hdr->srcaddr);
        while (datasz > 0) {
                csum += le32_to_cpu(*data++);
                datasz -= 4;
        }

        return cpu_to_le32(csum);
}

static int
kwboot_img_is_secure(void *img)
{
        struct opt_hdr_v1 *ohdr;

        for_each_opt_hdr_v1 (ohdr, img)
                if (ohdr->headertype == OPT_HDR_V1_SECURE_TYPE)
                        return 1;

        return 0;
}

static void *
kwboot_img_grow_data_right(void *img, size_t *size, size_t grow)
{
        struct main_hdr_v1 *hdr = img;
        void *result;

        /*
         * 32-bit checksum comes after end of image code, so we will be putting
         * new code there. So we get this pointer and then increase data size
         * (since increasing data size changes kwboot_img_csum32_ptr() return
         *  value).
         */
        result = kwboot_img_csum32_ptr(img);
        hdr->blocksize = cpu_to_le32(le32_to_cpu(hdr->blocksize) + grow);
        *size += grow;

        return result;
}

static void
kwboot_img_grow_hdr(void *img, size_t *size, size_t grow)
{
        uint32_t hdrsz, datasz, srcaddr;
        struct main_hdr_v1 *hdr = img;
        struct opt_hdr_v1 *ohdr;
        uint8_t *data;

        srcaddr = le32_to_cpu(hdr->srcaddr);

        /* calculate real used space in kwbimage header */
        if (kwbimage_version(img) == 0) {
                hdrsz = kwbheader_size(img);
        } else {
                hdrsz = sizeof(*hdr);
                for_each_opt_hdr_v1 (ohdr, hdr)
                        hdrsz += opt_hdr_v1_size(ohdr);
        }

        data = (uint8_t *)img + srcaddr;
        datasz = *size - srcaddr;

        /* only move data if there is not enough space */
        if (hdrsz + grow > srcaddr) {
                size_t need = hdrsz + grow - srcaddr;

                /* move data by enough bytes */
                memmove(data + need, data, datasz);

                hdr->srcaddr = cpu_to_le32(srcaddr + need);
                *size += need;
        }

        if (kwbimage_version(img) == 1) {
                hdrsz += grow;
                if (hdrsz > kwbheader_size(img)) {
                        hdr->headersz_msb = hdrsz >> 16;
                        hdr->headersz_lsb = cpu_to_le16(hdrsz & 0xffff);
                }
        }
}

static void *
kwboot_add_bin_ohdr_v1(void *img, size_t *size, uint32_t binsz)
{
        struct main_hdr_v1 *hdr = img;
        struct opt_hdr_v1 *ohdr;
        uint32_t num_args;
        uint32_t offset;
        uint32_t ohdrsz;
        uint8_t *prev_ext;

        if (hdr->ext) {
                for_each_opt_hdr_v1 (ohdr, img)
                        if (opt_hdr_v1_next(ohdr) == NULL)
                                break;

                prev_ext = opt_hdr_v1_ext(ohdr);
                ohdr = _opt_hdr_v1_next(ohdr);
        } else {
                ohdr = (void *)(hdr + 1);
                prev_ext = &hdr->ext;
        }

        /*
         * ARM executable code inside the BIN header on some mvebu platforms
         * (e.g. A370, AXP) must always be aligned with the 128-bit boundary.
         * This requirement can be met by inserting dummy arguments into
         * BIN header, if needed.
         */
        offset = &ohdr->data[4] - (char *)img;
        num_args = ((16 - offset % 16) % 16) / sizeof(uint32_t);

        ohdrsz = sizeof(*ohdr) + 4 + 4 * num_args + binsz + 4;
        kwboot_img_grow_hdr(hdr, size, ohdrsz);

        *prev_ext = 1;

        ohdr->headertype = OPT_HDR_V1_BINARY_TYPE;
        ohdr->headersz_msb = ohdrsz >> 16;
        ohdr->headersz_lsb = cpu_to_le16(ohdrsz & 0xffff);

        memset(&ohdr->data[0], 0, ohdrsz - sizeof(*ohdr));
        *(uint32_t *)&ohdr->data[0] = cpu_to_le32(num_args);

        return &ohdr->data[4 + 4 * num_args];
}

static void
_inject_baudrate_change_code(void *img, size_t *size, int for_data,
                             int old_baud, int new_baud)
{
        struct main_hdr_v1 *hdr = img;
        uint32_t orig_datasz;
        uint32_t codesz;
        uint8_t *code;

        if (for_data) {
                orig_datasz = le32_to_cpu(hdr->blocksize) - sizeof(uint32_t);

                codesz = sizeof(kwboot_baud_code) +
                         sizeof(kwboot_baud_code_data_jump);
                code = kwboot_img_grow_data_right(img, size, codesz);
        } else {
                codesz = sizeof(kwboot_baud_code_binhdr_pre) +
                         sizeof(kwboot_baud_code) +
                         sizeof(kwboot_baud_code_binhdr_post);
                code = kwboot_add_bin_ohdr_v1(img, size, codesz);

                codesz = sizeof(kwboot_baud_code_binhdr_pre);
                memcpy(code, kwboot_baud_code_binhdr_pre, codesz);
                code += codesz;
        }

        codesz = sizeof(kwboot_baud_code) - 2 * sizeof(uint32_t);
        memcpy(code, kwboot_baud_code, codesz);
        code += codesz;
        *(uint32_t *)code = cpu_to_le32(old_baud);
        code += sizeof(uint32_t);
        *(uint32_t *)code = cpu_to_le32(new_baud);
        code += sizeof(uint32_t);

        if (for_data) {
                codesz = sizeof(kwboot_baud_code_data_jump) - sizeof(uint32_t);
                memcpy(code, kwboot_baud_code_data_jump, codesz);
                code += codesz;
                *(uint32_t *)code = hdr->execaddr;
                code += sizeof(uint32_t);
                hdr->execaddr = cpu_to_le32(le32_to_cpu(hdr->destaddr) + orig_datasz);
        } else {
                codesz = sizeof(kwboot_baud_code_binhdr_post);
                memcpy(code, kwboot_baud_code_binhdr_post, codesz);
                code += codesz;
        }
}

static int
kwboot_img_patch(void *img, size_t *size, int baudrate)
{
        struct main_hdr_v1 *hdr;
        uint32_t srcaddr;
        uint8_t csum;
        size_t hdrsz;
        int image_ver;
        int is_secure;

        hdr = img;

        if (*size < sizeof(struct main_hdr_v1))
                goto err;

        image_ver = kwbimage_version(img);
        if (image_ver != 0 && image_ver != 1) {
                fprintf(stderr, "Invalid image header version\n");
                goto err;
        }

        hdrsz = kwbheader_size(hdr);

        if (*size < hdrsz)
                goto err;

        csum = kwboot_hdr_csum8(hdr) - hdr->checksum;
        if (csum != hdr->checksum)
                goto err;

        srcaddr = le32_to_cpu(hdr->srcaddr);

        switch (hdr->blockid) {
        case IBR_HDR_SATA_ID:
                if (srcaddr < 1)
                        goto err;

                hdr->srcaddr = cpu_to_le32((srcaddr - 1) * 512);
                break;

        case IBR_HDR_SDIO_ID:
                hdr->srcaddr = cpu_to_le32(srcaddr * 512);
                break;

        case IBR_HDR_PEX_ID:
                if (srcaddr == 0xFFFFFFFF)
                        hdr->srcaddr = cpu_to_le32(hdrsz);
                break;

        case IBR_HDR_SPI_ID:
                if (hdr->destaddr == cpu_to_le32(0xFFFFFFFF)) {
                        kwboot_printv("Patching destination and execution addresses from SPI/NOR XIP area to DDR area 0x00800000\n");
                        hdr->destaddr = cpu_to_le32(0x00800000);
                        hdr->execaddr = cpu_to_le32(0x00800000);
                }
                break;
        }

        if (hdrsz > le32_to_cpu(hdr->srcaddr) ||
            *size < le32_to_cpu(hdr->srcaddr) + le32_to_cpu(hdr->blocksize))
                goto err;

        if (kwboot_img_csum32(img) != *kwboot_img_csum32_ptr(img))
                goto err;

        is_secure = kwboot_img_is_secure(img);

        if (hdr->blockid != IBR_HDR_UART_ID) {
                if (is_secure) {
                        fprintf(stderr,
                                "Image has secure header with signature for non-UART booting\n");
                        goto err;
                }

                kwboot_printv("Patching image boot signature to UART\n");
                hdr->blockid = IBR_HDR_UART_ID;
        }

        if (!is_secure) {
                if (image_ver == 1) {
                        /*
                         * Tell BootROM to send BootROM messages to UART port
                         * number 0 (used also for UART booting) with default
                         * baudrate (which should be 115200) and do not touch
                         * UART MPP configuration.
                         */
                        hdr->flags |= 0x1;
                        hdr->options &= ~0x1F;
                        hdr->options |= MAIN_HDR_V1_OPT_BAUD_DEFAULT;
                        hdr->options |= 0 << 3;
                }
                if (image_ver == 0)
                        ((struct main_hdr_v0 *)img)->nandeccmode = IBR_HDR_ECC_DISABLED;
                hdr->nandpagesize = 0;
        }

        if (baudrate) {
                if (image_ver == 0) {
                        fprintf(stderr,
                                "Cannot inject code for changing baudrate into v0 image header\n");
                        goto err;
                }

                if (is_secure) {
                        fprintf(stderr,
                                "Cannot inject code for changing baudrate into image with secure header\n");
                        goto err;
                }

                /*
                 * First inject code that changes the baudrate from the default
                 * value of 115200 Bd to requested value. This code is inserted
                 * as a new opt hdr, so it is executed by BootROM after the
                 * header part is received.
                 */
                kwboot_printv("Injecting binary header code for changing baudrate to %d Bd\n",
                              baudrate);
                _inject_baudrate_change_code(img, size, 0, 115200, baudrate);

                /*
                 * Now inject code that changes the baudrate back to 115200 Bd.
                 * This code is appended after the data part of the image, and
                 * execaddr is changed so that it is executed before U-Boot
                 * proper.
                 */
                kwboot_printv("Injecting code for changing baudrate back\n");
                _inject_baudrate_change_code(img, size, 1, baudrate, 115200);

                /* Update the 32-bit data checksum */
                *kwboot_img_csum32_ptr(img) = kwboot_img_csum32(img);

                /* recompute header size */
                hdrsz = kwbheader_size(hdr);
        }

        if (hdrsz % KWBOOT_XM_BLKSZ) {
                size_t grow = KWBOOT_XM_BLKSZ - hdrsz % KWBOOT_XM_BLKSZ;

                if (is_secure) {
                        fprintf(stderr, "Cannot align image with secure header\n");
                        goto err;
                }

                kwboot_printv("Aligning image header to Xmodem block size\n");
                kwboot_img_grow_hdr(img, size, grow);
        }

        hdr->checksum = kwboot_hdr_csum8(hdr) - csum;

        *size = le32_to_cpu(hdr->srcaddr) + le32_to_cpu(hdr->blocksize);
        return 0;
err:
        errno = EINVAL;
        return -1;
}

static void
kwboot_usage(FILE *stream, char *progname)
{
        fprintf(stream,
                "Usage: %s [OPTIONS] [-b <image> | -D <image> | -b | -d ] [-B <baud> ] [-t] <TTY>\n",
                progname);
        fprintf(stream, "\n");
        fprintf(stream,
                "  -b <image>: boot <image> with preamble (Kirkwood, Avanta, Armada 370/XP/375/38x/39x)\n");
        fprintf(stream,
                "  -D <image>: boot <image> without preamble (Dove)\n");
        fprintf(stream, "  -b: enter xmodem boot mode\n");
        fprintf(stream, "  -d: enter console debug mode\n");
        fprintf(stream, "  -a: use timings for Armada XP\n");
        fprintf(stream, "  -s <resp-timeo>: use specific response-timeout\n");
        fprintf(stream,
                "  -o <block-timeo>: use specific xmodem block timeout\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;
        int bootmsg;
        int debugmsg;
        void *img;
        size_t size;
        size_t after_img_rsv;
        int baudrate;
        int prev_optind;
        int c;

        rv = 1;
        tty = -1;
        bootmsg = 0;
        debugmsg = 0;
        imgpath = NULL;
        img = NULL;
        term = 0;
        size = 0;
        after_img_rsv = KWBOOT_XM_BLKSZ;
        baudrate = 115200;

        printf("kwboot version %s\n", PLAIN_VERSION);

        kwboot_verbose = isatty(STDOUT_FILENO);

        do {
                prev_optind = optind;
                c = getopt(argc, argv, "hbptaB:dD:q:s:o:");
                if (c < 0)
                        break;

                switch (c) {
                case 'b':
                        if (imgpath || bootmsg || debugmsg)
                                goto usage;
                        bootmsg = 1;
                        if (prev_optind == optind)
                                goto usage;
                        /* Option -b could have optional argument which specify image path */
                        if (optind < argc && argv[optind] && argv[optind][0] != '-')
                                imgpath = argv[optind++];
                        break;

                case 'D':
                        if (imgpath || bootmsg || debugmsg)
                                goto usage;
                        bootmsg = 0;
                        imgpath = optarg;
                        break;

                case 'd':
                        if (imgpath || bootmsg || debugmsg)
                                goto usage;
                        debugmsg = 1;
                        break;

                case 'p':
                        /* nop, for backward compatibility */
                        break;

                case 't':
                        term = 1;
                        break;

                case 'a':
                        msg_rsp_timeo = KWBOOT_MSG_RSP_TIMEO_AXP;
                        break;

                case 'q':
                        /* nop, for backward compatibility */
                        break;

                case 's':
                        msg_rsp_timeo = atoi(optarg);
                        break;

                case 'o':
                        blk_rsp_timeo = atoi(optarg);
                        break;

                case 'B':
                        baudrate = atoi(optarg);
                        break;

                case 'h':
                        rv = 0;
                default:
                        goto usage;
                }
        } while (1);

        if (!bootmsg && !term && !debugmsg && !imgpath)
                goto usage;

        /*
         * If there is no remaining argument but optional imgpath was parsed
         * then it means that optional imgpath was eaten by getopt parser.
         * Reassing imgpath to required ttypath argument.
         */
        if (optind == argc && imgpath) {
                ttypath = imgpath;
                imgpath = NULL;
        } else if (optind + 1 == argc) {
                ttypath = argv[optind];
        } else {
                goto usage;
        }

        /* boot and debug message use baudrate 115200 */
        if (((bootmsg && !imgpath) || debugmsg) && baudrate != 115200) {
                fprintf(stderr, "Baudrate other than 115200 cannot be used for this operation.\n");
                goto usage;
        }

        tty = kwboot_open_tty(ttypath, baudrate);
        if (tty < 0) {
                perror(ttypath);
                goto out;
        }

        /*
         * initial baudrate for image transfer is always 115200,
         * the change to different baudrate is done only after the header is sent
         */
        if (imgpath && baudrate != 115200) {
                rc = kwboot_tty_change_baudrate(tty, 115200);
                if (rc) {
                        perror(ttypath);
                        goto out;
                }
        }

        if (baudrate == 115200)
                /* do not change baudrate during Xmodem to the same value */
                baudrate = 0;
        else
                /* ensure we have enough space for baudrate change code */
                after_img_rsv += sizeof(struct opt_hdr_v1) + 8 + 16 +
                                 sizeof(kwboot_baud_code_binhdr_pre) +
                                 sizeof(kwboot_baud_code) +
                                 sizeof(kwboot_baud_code_binhdr_post) +
                                 KWBOOT_XM_BLKSZ +
                                 sizeof(kwboot_baud_code) +
                                 sizeof(kwboot_baud_code_data_jump) +
                                 KWBOOT_XM_BLKSZ;

        if (imgpath) {
                img = kwboot_read_image(imgpath, &size, after_img_rsv);
                if (!img) {
                        perror(imgpath);
                        goto out;
                }

                rc = kwboot_img_patch(img, &size, baudrate);
                if (rc) {
                        fprintf(stderr, "%s: Invalid image.\n", imgpath);
                        goto out;
                }
        }

        if (debugmsg) {
                rc = kwboot_debugmsg(tty);
                if (rc)
                        goto out;
        } else if (bootmsg) {
                rc = kwboot_bootmsg(tty);
                if (rc)
                        goto out;
        }

        if (img) {
                rc = kwboot_xmodem(tty, img, size, baudrate);
                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)
                free(img);

        return rv;

usage:
        kwboot_usage(rv ? stderr : stdout, basename(argv[0]));
        goto out;
}