/*
 * (C) Copyright 2000-2004
 * Wolfgang Denk, DENX Software Engineering, wd@denx.de.
 *
 * SPDX-License-Identifier:     GPL-2.0+
 */

/*
 * Serial up- and download support
 */
#include <common.h>
#include <command.h>
#include <s_record.h>
#include <net.h>
#include <exports.h>
#include <xyzModem.h>

DECLARE_GLOBAL_DATA_PTR;

#if defined(CONFIG_CMD_LOADB)
static ulong load_serial_ymodem(ulong offset, int mode);
#endif

#if defined(CONFIG_CMD_LOADS)
static ulong load_serial(long offset);
static int read_record(char *buf, ulong len);
# if defined(CONFIG_CMD_SAVES)
static int save_serial(ulong offset, ulong size);
static int write_record(char *buf);
#endif

static int do_echo = 1;
#endif

/* -------------------------------------------------------------------- */

#if defined(CONFIG_CMD_LOADS)
static int do_load_serial(cmd_tbl_t *cmdtp, int flag, int argc,
                          char * const argv[])
{
        long offset = 0;
        ulong addr;
        int i;
        char *env_echo;
        int rcode = 0;
#ifdef  CONFIG_SYS_LOADS_BAUD_CHANGE
        int load_baudrate, current_baudrate;

        load_baudrate = current_baudrate = gd->baudrate;
#endif

        if (((env_echo = getenv("loads_echo")) != NULL) && (*env_echo == '1')) {
                do_echo = 1;
        } else {
                do_echo = 0;
        }

#ifdef  CONFIG_SYS_LOADS_BAUD_CHANGE
        if (argc >= 2) {
                offset = simple_strtol(argv[1], NULL, 16);
        }
        if (argc == 3) {
                load_baudrate = (int)simple_strtoul(argv[2], NULL, 10);

                /* default to current baudrate */
                if (load_baudrate == 0)
                        load_baudrate = current_baudrate;
        }
        if (load_baudrate != current_baudrate) {
                printf("## Switch baudrate to %d bps and press ENTER ...\n",
                        load_baudrate);
                udelay(50000);
                gd->baudrate = load_baudrate;
                serial_setbrg();
                udelay(50000);
                for (;;) {
                        if (getc() == '\r')
                                break;
                }
        }
#else   /* ! CONFIG_SYS_LOADS_BAUD_CHANGE */
        if (argc == 2) {
                offset = simple_strtol(argv[1], NULL, 16);
        }
#endif  /* CONFIG_SYS_LOADS_BAUD_CHANGE */

        printf("## Ready for S-Record download ...\n");

        addr = load_serial(offset);

        /*
         * Gather any trailing characters (for instance, the ^D which
         * is sent by 'cu' after sending a file), and give the
         * box some time (100 * 1 ms)
         */
        for (i=0; i<100; ++i) {
                if (tstc()) {
                        (void) getc();
                }
                udelay(1000);
        }

        if (addr == ~0) {
                printf("## S-Record download aborted\n");
                rcode = 1;
        } else {
                printf("## Start Addr      = 0x%08lX\n", addr);
                load_addr = addr;
        }

#ifdef  CONFIG_SYS_LOADS_BAUD_CHANGE
        if (load_baudrate != current_baudrate) {
                printf("## Switch baudrate to %d bps and press ESC ...\n",
                        current_baudrate);
                udelay(50000);
                gd->baudrate = current_baudrate;
                serial_setbrg();
                udelay(50000);
                for (;;) {
                        if (getc() == 0x1B) /* ESC */
                                break;
                }
        }
#endif
        return rcode;
}

static ulong load_serial(long offset)
{
        char    record[SREC_MAXRECLEN + 1];     /* buffer for one S-Record      */
        char    binbuf[SREC_MAXBINLEN];         /* buffer for binary data       */
        int     binlen;                         /* no. of data bytes in S-Rec.  */
        int     type;                           /* return code for record type  */
        ulong   addr;                           /* load address from S-Record   */
        ulong   size;                           /* number of bytes transferred  */
        ulong   store_addr;
        ulong   start_addr = ~0;
        ulong   end_addr   =  0;
        int     line_count =  0;

        while (read_record(record, SREC_MAXRECLEN + 1) >= 0) {
                type = srec_decode(record, &binlen, &addr, binbuf);

                if (type < 0) {
                        return (~0);            /* Invalid S-Record             */
                }

                switch (type) {
                case SREC_DATA2:
                case SREC_DATA3:
                case SREC_DATA4:
                    store_addr = addr + offset;
#ifndef CONFIG_SYS_NO_FLASH
                    if (addr2info(store_addr)) {
                        int rc;

                        rc = flash_write((char *)binbuf,store_addr,binlen);
                        if (rc != 0) {
                                flash_perror(rc);
                                return (~0);
                        }
                    } else
#endif
                    {
                        memcpy((char *)(store_addr), binbuf, binlen);
                    }
                    if ((store_addr) < start_addr)
                        start_addr = store_addr;
                    if ((store_addr + binlen - 1) > end_addr)
                        end_addr = store_addr + binlen - 1;
                    break;
                case SREC_END2:
                case SREC_END3:
                case SREC_END4:
                    udelay(10000);
                    size = end_addr - start_addr + 1;
                    printf("\n"
                            "## First Load Addr = 0x%08lX\n"
                            "## Last  Load Addr = 0x%08lX\n"
                            "## Total Size      = 0x%08lX = %ld Bytes\n",
                            start_addr, end_addr, size, size
                    );
                    flush_cache(start_addr, size);
                    setenv_hex("filesize", size);
                    return (addr);
                case SREC_START:
                    break;
                default:
                    break;
                }
                if (!do_echo) { /* print a '.' every 100 lines */
                        if ((++line_count % 100) == 0)
                                putc('.');
                }
        }

        return (~0);                    /* Download aborted             */
}

static int read_record(char *buf, ulong len)
{
        char *p;
        char c;

        --len;  /* always leave room for terminating '\0' byte */

        for (p=buf; p < buf+len; ++p) {
                c = getc();             /* read character               */
                if (do_echo)
                        putc(c);        /* ... and echo it              */

                switch (c) {
                case '\r':
                case '\n':
                        *p = '\0';
                        return (p - buf);
                case '\0':
                case 0x03:                      /* ^C - Control C               */
                        return (-1);
                default:
                        *p = c;
                }

            /* Check for the console hangup (if any different from serial) */
            if (gd->jt[XF_getc] != getc) {
                if (ctrlc()) {
                    return (-1);
                }
            }
        }

        /* line too long - truncate */
        *p = '\0';
        return (p - buf);
}

#if defined(CONFIG_CMD_SAVES)

int do_save_serial (cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
{
        ulong offset = 0;
        ulong size   = 0;
#ifdef  CONFIG_SYS_LOADS_BAUD_CHANGE
        int save_baudrate, current_baudrate;

        save_baudrate = current_baudrate = gd->baudrate;
#endif

        if (argc >= 2) {
                offset = simple_strtoul(argv[1], NULL, 16);
        }
#ifdef  CONFIG_SYS_LOADS_BAUD_CHANGE
        if (argc >= 3) {
                size = simple_strtoul(argv[2], NULL, 16);
        }
        if (argc == 4) {
                save_baudrate = (int)simple_strtoul(argv[3], NULL, 10);

                /* default to current baudrate */
                if (save_baudrate == 0)
                        save_baudrate = current_baudrate;
        }
        if (save_baudrate != current_baudrate) {
                printf("## Switch baudrate to %d bps and press ENTER ...\n",
                        save_baudrate);
                udelay(50000);
                gd->baudrate = save_baudrate;
                serial_setbrg();
                udelay(50000);
                for (;;) {
                        if (getc() == '\r')
                                break;
                }
        }
#else   /* ! CONFIG_SYS_LOADS_BAUD_CHANGE */
        if (argc == 3) {
                size = simple_strtoul(argv[2], NULL, 16);
        }
#endif  /* CONFIG_SYS_LOADS_BAUD_CHANGE */

        printf("## Ready for S-Record upload, press ENTER to proceed ...\n");
        for (;;) {
                if (getc() == '\r')
                        break;
        }
        if (save_serial(offset, size)) {
                printf("## S-Record upload aborted\n");
        } else {
                printf("## S-Record upload complete\n");
        }
#ifdef  CONFIG_SYS_LOADS_BAUD_CHANGE
        if (save_baudrate != current_baudrate) {
                printf("## Switch baudrate to %d bps and press ESC ...\n",
                        (int)current_baudrate);
                udelay(50000);
                gd->baudrate = current_baudrate;
                serial_setbrg();
                udelay(50000);
                for (;;) {
                        if (getc() == 0x1B) /* ESC */
                                break;
                }
        }
#endif
        return 0;
}

#define SREC3_START                             "S0030000FC\n"
#define SREC3_FORMAT                    "S3%02X%08lX%s%02X\n"
#define SREC3_END                               "S70500000000FA\n"
#define SREC_BYTES_PER_RECORD   16

static int save_serial(ulong address, ulong count)
{
        int i, c, reclen, checksum, length;
        char *hex = "0123456789ABCDEF";
        char    record[2*SREC_BYTES_PER_RECORD+16];     /* buffer for one S-Record      */
        char    data[2*SREC_BYTES_PER_RECORD+1];        /* buffer for hex data  */

        reclen = 0;
        checksum  = 0;

        if(write_record(SREC3_START))                   /* write the header */
                return (-1);
        do {
                if(count) {                                             /* collect hex data in the buffer  */
                        c = *(volatile uchar*)(address + reclen);       /* get one byte    */
                        checksum += c;                                                  /* accumulate checksum */
                        data[2*reclen]   = hex[(c>>4)&0x0f];
                        data[2*reclen+1] = hex[c & 0x0f];
                        data[2*reclen+2] = '\0';
                        ++reclen;
                        --count;
                }
                if(reclen == SREC_BYTES_PER_RECORD || count == 0) {
                        /* enough data collected for one record: dump it */
                        if(reclen) {    /* build & write a data record: */
                                /* address + data + checksum */
                                length = 4 + reclen + 1;

                                /* accumulate length bytes into checksum */
                                for(i = 0; i < 2; i++)
                                        checksum += (length >> (8*i)) & 0xff;

                                /* accumulate address bytes into checksum: */
                                for(i = 0; i < 4; i++)
                                        checksum += (address >> (8*i)) & 0xff;

                                /* make proper checksum byte: */
                                checksum = ~checksum & 0xff;

                                /* output one record: */
                                sprintf(record, SREC3_FORMAT, length, address, data, checksum);
                                if(write_record(record))
                                        return (-1);
                        }
                        address  += reclen;  /* increment address */
                        checksum  = 0;
                        reclen    = 0;
                }
        }
        while(count);
        if(write_record(SREC3_END))     /* write the final record */
                return (-1);
        return(0);
}

static int write_record(char *buf)
{
        char c;

        while((c = *buf++))
                putc(c);

        /* Check for the console hangup (if any different from serial) */

        if (ctrlc()) {
            return (-1);
        }
        return (0);
}
# endif

#endif


#if defined(CONFIG_CMD_LOADB)
/*
 * loadb command (load binary) included
 */
#define XON_CHAR        17
#define XOFF_CHAR       19
#define START_CHAR      0x01
#define ETX_CHAR        0x03
#define END_CHAR        0x0D
#define SPACE           0x20
#define K_ESCAPE        0x23
#define SEND_TYPE       'S'
#define DATA_TYPE       'D'
#define ACK_TYPE        'Y'
#define NACK_TYPE       'N'
#define BREAK_TYPE      'B'
#define tochar(x) ((char) (((x) + SPACE) & 0xff))
#define untochar(x) ((int) (((x) - SPACE) & 0xff))

static void set_kerm_bin_mode(unsigned long *);
static int k_recv(void);
static ulong load_serial_bin(ulong offset);


static char his_eol;        /* character he needs at end of packet */
static int  his_pad_count;  /* number of pad chars he needs */
static char his_pad_char;   /* pad chars he needs */
static char his_quote;      /* quote chars he'll use */

static int do_load_serial_bin(cmd_tbl_t *cmdtp, int flag, int argc,
                              char * const argv[])
{
        ulong offset = 0;
        ulong addr;
        int load_baudrate, current_baudrate;
        int rcode = 0;
        char *s;

        /* pre-set offset from CONFIG_SYS_LOAD_ADDR */
        offset = CONFIG_SYS_LOAD_ADDR;

        /* pre-set offset from $loadaddr */
        if ((s = getenv("loadaddr")) != NULL) {
                offset = simple_strtoul(s, NULL, 16);
        }

        load_baudrate = current_baudrate = gd->baudrate;

        if (argc >= 2) {
                offset = simple_strtoul(argv[1], NULL, 16);
        }
        if (argc == 3) {
                load_baudrate = (int)simple_strtoul(argv[2], NULL, 10);

                /* default to current baudrate */
                if (load_baudrate == 0)
                        load_baudrate = current_baudrate;
        }

        if (load_baudrate != current_baudrate) {
                printf("## Switch baudrate to %d bps and press ENTER ...\n",
                        load_baudrate);
                udelay(50000);
                gd->baudrate = load_baudrate;
                serial_setbrg();
                udelay(50000);
                for (;;) {
                        if (getc() == '\r')
                                break;
                }
        }

        if (strcmp(argv[0],"loady")==0) {
                printf("## Ready for binary (ymodem) download "
                        "to 0x%08lX at %d bps...\n",
                        offset,
                        load_baudrate);

                addr = load_serial_ymodem(offset, xyzModem_ymodem);

        } else if (strcmp(argv[0],"loadx")==0) {
                printf("## Ready for binary (xmodem) download "
                        "to 0x%08lX at %d bps...\n",
                        offset,
                        load_baudrate);

                addr = load_serial_ymodem(offset, xyzModem_xmodem);

        } else {

                printf("## Ready for binary (kermit) download "
                        "to 0x%08lX at %d bps...\n",
                        offset,
                        load_baudrate);
                addr = load_serial_bin(offset);

                if (addr == ~0) {
                        load_addr = 0;
                        printf("## Binary (kermit) download aborted\n");
                        rcode = 1;
                } else {
                        printf("## Start Addr      = 0x%08lX\n", addr);
                        load_addr = addr;
                }
        }
        if (load_baudrate != current_baudrate) {
                printf("## Switch baudrate to %d bps and press ESC ...\n",
                        current_baudrate);
                udelay(50000);
                gd->baudrate = current_baudrate;
                serial_setbrg();
                udelay(50000);
                for (;;) {
                        if (getc() == 0x1B) /* ESC */
                                break;
                }
        }

        return rcode;
}


static ulong load_serial_bin(ulong offset)
{
        int size, i;

        set_kerm_bin_mode((ulong *) offset);
        size = k_recv();

        /*
         * Gather any trailing characters (for instance, the ^D which
         * is sent by 'cu' after sending a file), and give the
         * box some time (100 * 1 ms)
         */
        for (i=0; i<100; ++i) {
                if (tstc()) {
                        (void) getc();
                }
                udelay(1000);
        }

        flush_cache(offset, size);

        printf("## Total Size      = 0x%08x = %d Bytes\n", size, size);
        setenv_hex("filesize", size);

        return offset;
}

static void send_pad(void)
{
        int count = his_pad_count;

        while (count-- > 0)
                putc(his_pad_char);
}

/* converts escaped kermit char to binary char */
static char ktrans(char in)
{
        if ((in & 0x60) == 0x40) {
                return (char) (in & ~0x40);
        } else if ((in & 0x7f) == 0x3f) {
                return (char) (in | 0x40);
        } else
                return in;
}

static int chk1(char *buffer)
{
        int total = 0;

        while (*buffer) {
                total += *buffer++;
        }
        return (int) ((total + ((total >> 6) & 0x03)) & 0x3f);
}

static void s1_sendpacket(char *packet)
{
        send_pad();
        while (*packet) {
                putc(*packet++);
        }
}

static char a_b[24];
static void send_ack(int n)
{
        a_b[0] = START_CHAR;
        a_b[1] = tochar(3);
        a_b[2] = tochar(n);
        a_b[3] = ACK_TYPE;
        a_b[4] = '\0';
        a_b[4] = tochar(chk1(&a_b[1]));
        a_b[5] = his_eol;
        a_b[6] = '\0';
        s1_sendpacket(a_b);
}

static void send_nack(int n)
{
        a_b[0] = START_CHAR;
        a_b[1] = tochar(3);
        a_b[2] = tochar(n);
        a_b[3] = NACK_TYPE;
        a_b[4] = '\0';
        a_b[4] = tochar(chk1(&a_b[1]));
        a_b[5] = his_eol;
        a_b[6] = '\0';
        s1_sendpacket(a_b);
}


static void (*os_data_init)(void);
static void (*os_data_char)(char new_char);
static int os_data_state, os_data_state_saved;
static char *os_data_addr, *os_data_addr_saved;
static char *bin_start_address;

static void bin_data_init(void)
{
        os_data_state = 0;
        os_data_addr = bin_start_address;
}

static void os_data_save(void)
{
        os_data_state_saved = os_data_state;
        os_data_addr_saved = os_data_addr;
}

static void os_data_restore(void)
{
        os_data_state = os_data_state_saved;
        os_data_addr = os_data_addr_saved;
}

static void bin_data_char(char new_char)
{
        switch (os_data_state) {
        case 0:                                 /* data */
                *os_data_addr++ = new_char;
                break;
        }
}

static void set_kerm_bin_mode(unsigned long *addr)
{
        bin_start_address = (char *) addr;
        os_data_init = bin_data_init;
        os_data_char = bin_data_char;
}


/* k_data_* simply handles the kermit escape translations */
static int k_data_escape, k_data_escape_saved;
static void k_data_init(void)
{
        k_data_escape = 0;
        os_data_init();
}

static void k_data_save(void)
{
        k_data_escape_saved = k_data_escape;
        os_data_save();
}

static void k_data_restore(void)
{
        k_data_escape = k_data_escape_saved;
        os_data_restore();
}

static void k_data_char(char new_char)
{
        if (k_data_escape) {
                /* last char was escape - translate this character */
                os_data_char(ktrans(new_char));
                k_data_escape = 0;
        } else {
                if (new_char == his_quote) {
                        /* this char is escape - remember */
                        k_data_escape = 1;
                } else {
                        /* otherwise send this char as-is */
                        os_data_char(new_char);
                }
        }
}

#define SEND_DATA_SIZE  20
static char send_parms[SEND_DATA_SIZE];
static char *send_ptr;

/* handle_send_packet interprits the protocol info and builds and
   sends an appropriate ack for what we can do */
static void handle_send_packet(int n)
{
        int length = 3;
        int bytes;

        /* initialize some protocol parameters */
        his_eol = END_CHAR;             /* default end of line character */
        his_pad_count = 0;
        his_pad_char = '\0';
        his_quote = K_ESCAPE;

        /* ignore last character if it filled the buffer */
        if (send_ptr == &send_parms[SEND_DATA_SIZE - 1])
                --send_ptr;
        bytes = send_ptr - send_parms;  /* how many bytes we'll process */
        do {
                if (bytes-- <= 0)
                        break;
                /* handle MAXL - max length */
                /* ignore what he says - most I'll take (here) is 94 */
                a_b[++length] = tochar(94);
                if (bytes-- <= 0)
                        break;
                /* handle TIME - time you should wait for my packets */
                /* ignore what he says - don't wait for my ack longer than 1 second */
                a_b[++length] = tochar(1);
                if (bytes-- <= 0)
                        break;
                /* handle NPAD - number of pad chars I need */
                /* remember what he says - I need none */
                his_pad_count = untochar(send_parms[2]);
                a_b[++length] = tochar(0);
                if (bytes-- <= 0)
                        break;
                /* handle PADC - pad chars I need */
                /* remember what he says - I need none */
                his_pad_char = ktrans(send_parms[3]);
                a_b[++length] = 0x40;   /* He should ignore this */
                if (bytes-- <= 0)
                        break;
                /* handle EOL - end of line he needs */
                /* remember what he says - I need CR */
                his_eol = untochar(send_parms[4]);
                a_b[++length] = tochar(END_CHAR);
                if (bytes-- <= 0)
                        break;
                /* handle QCTL - quote control char he'll use */
                /* remember what he says - I'll use '#' */
                his_quote = send_parms[5];
                a_b[++length] = '#';
                if (bytes-- <= 0)
                        break;
                /* handle QBIN - 8-th bit prefixing */
                /* ignore what he says - I refuse */
                a_b[++length] = 'N';
                if (bytes-- <= 0)
                        break;
                /* handle CHKT - the clock check type */
                /* ignore what he says - I do type 1 (for now) */
                a_b[++length] = '1';
                if (bytes-- <= 0)
                        break;
                /* handle REPT - the repeat prefix */
                /* ignore what he says - I refuse (for now) */
                a_b[++length] = 'N';
                if (bytes-- <= 0)
                        break;
                /* handle CAPAS - the capabilities mask */
                /* ignore what he says - I only do long packets - I don't do windows */
                a_b[++length] = tochar(2);      /* only long packets */
                a_b[++length] = tochar(0);      /* no windows */
                a_b[++length] = tochar(94);     /* large packet msb */
                a_b[++length] = tochar(94);     /* large packet lsb */
        } while (0);

        a_b[0] = START_CHAR;
        a_b[1] = tochar(length);
        a_b[2] = tochar(n);
        a_b[3] = ACK_TYPE;
        a_b[++length] = '\0';
        a_b[length] = tochar(chk1(&a_b[1]));
        a_b[++length] = his_eol;
        a_b[++length] = '\0';
        s1_sendpacket(a_b);
}

/* k_recv receives a OS Open image file over kermit line */
static int k_recv(void)
{
        char new_char;
        char k_state, k_state_saved;
        int sum;
        int done;
        int length;
        int n, last_n;
        int len_lo, len_hi;

        /* initialize some protocol parameters */
        his_eol = END_CHAR;             /* default end of line character */
        his_pad_count = 0;
        his_pad_char = '\0';
        his_quote = K_ESCAPE;

        /* initialize the k_recv and k_data state machine */
        done = 0;
        k_state = 0;
        k_data_init();
        k_state_saved = k_state;
        k_data_save();
        n = 0;                          /* just to get rid of a warning */
        last_n = -1;

        /* expect this "type" sequence (but don't check):
           S: send initiate
           F: file header
           D: data (multiple)
           Z: end of file
           B: break transmission
         */

        /* enter main loop */
        while (!done) {
                /* set the send packet pointer to begining of send packet parms */
                send_ptr = send_parms;

                /* With each packet, start summing the bytes starting with the length.
                   Save the current sequence number.
                   Note the type of the packet.
                   If a character less than SPACE (0x20) is received - error.
                 */

#if 0
                /* OLD CODE, Prior to checking sequence numbers */
                /* first have all state machines save current states */
                k_state_saved = k_state;
                k_data_save ();
#endif

                /* get a packet */
                /* wait for the starting character or ^C */
                for (;;) {
                        switch (getc ()) {
                        case START_CHAR:        /* start packet */
                                goto START;
                        case ETX_CHAR:          /* ^C waiting for packet */
                                return (0);
                        default:
                                ;
                        }
                }
START:
                /* get length of packet */
                sum = 0;
                new_char = getc();
                if ((new_char & 0xE0) == 0)
                        goto packet_error;
                sum += new_char & 0xff;
                length = untochar(new_char);
                /* get sequence number */
                new_char = getc();
                if ((new_char & 0xE0) == 0)
                        goto packet_error;
                sum += new_char & 0xff;
                n = untochar(new_char);
                --length;

                /* NEW CODE - check sequence numbers for retried packets */
                /* Note - this new code assumes that the sequence number is correctly
                 * received.  Handling an invalid sequence number adds another layer
                 * of complexity that may not be needed - yet!  At this time, I'm hoping
                 * that I don't need to buffer the incoming data packets and can write
                 * the data into memory in real time.
                 */
                if (n == last_n) {
                        /* same sequence number, restore the previous state */
                        k_state = k_state_saved;
                        k_data_restore();
                } else {
                        /* new sequence number, checkpoint the download */
                        last_n = n;
                        k_state_saved = k_state;
                        k_data_save();
                }
                /* END NEW CODE */

                /* get packet type */
                new_char = getc();
                if ((new_char & 0xE0) == 0)
                        goto packet_error;
                sum += new_char & 0xff;
                k_state = new_char;
                --length;
                /* check for extended length */
                if (length == -2) {
                        /* (length byte was 0, decremented twice) */
                        /* get the two length bytes */
                        new_char = getc();
                        if ((new_char & 0xE0) == 0)
                                goto packet_error;
                        sum += new_char & 0xff;
                        len_hi = untochar(new_char);
                        new_char = getc();
                        if ((new_char & 0xE0) == 0)
                                goto packet_error;
                        sum += new_char & 0xff;
                        len_lo = untochar(new_char);
                        length = len_hi * 95 + len_lo;
                        /* check header checksum */
                        new_char = getc();
                        if ((new_char & 0xE0) == 0)
                                goto packet_error;
                        if (new_char != tochar((sum + ((sum >> 6) & 0x03)) & 0x3f))
                                goto packet_error;
                        sum += new_char & 0xff;
/* --length; */ /* new length includes only data and block check to come */
                }
                /* bring in rest of packet */
                while (length > 1) {
                        new_char = getc();
                        if ((new_char & 0xE0) == 0)
                                goto packet_error;
                        sum += new_char & 0xff;
                        --length;
                        if (k_state == DATA_TYPE) {
                                /* pass on the data if this is a data packet */
                                k_data_char (new_char);
                        } else if (k_state == SEND_TYPE) {
                                /* save send pack in buffer as is */
                                *send_ptr++ = new_char;
                                /* if too much data, back off the pointer */
                                if (send_ptr >= &send_parms[SEND_DATA_SIZE])
                                        --send_ptr;
                        }
                }
                /* get and validate checksum character */
                new_char = getc();
                if ((new_char & 0xE0) == 0)
                        goto packet_error;
                if (new_char != tochar((sum + ((sum >> 6) & 0x03)) & 0x3f))
                        goto packet_error;
                /* get END_CHAR */
                new_char = getc();
                if (new_char != END_CHAR) {
                  packet_error:
                        /* restore state machines */
                        k_state = k_state_saved;
                        k_data_restore();
                        /* send a negative acknowledge packet in */
                        send_nack(n);
                } else if (k_state == SEND_TYPE) {
                        /* crack the protocol parms, build an appropriate ack packet */
                        handle_send_packet(n);
                } else {
                        /* send simple acknowledge packet in */
                        send_ack(n);
                        /* quit if end of transmission */
                        if (k_state == BREAK_TYPE)
                                done = 1;
                }
        }
        return ((ulong) os_data_addr - (ulong) bin_start_address);
}

static int getcxmodem(void) {
        if (tstc())
                return (getc());
        return -1;
}
static ulong load_serial_ymodem(ulong offset, int mode)
{
        int size;
        int err;
        int res;
        connection_info_t info;
        char ymodemBuf[1024];
        ulong store_addr = ~0;
        ulong addr = 0;

        size = 0;
        info.mode = mode;
        res = xyzModem_stream_open(&info, &err);
        if (!res) {

                while ((res =
                        xyzModem_stream_read(ymodemBuf, 1024, &err)) > 0) {
                        store_addr = addr + offset;
                        size += res;
                        addr += res;
#ifndef CONFIG_SYS_NO_FLASH
                        if (addr2info(store_addr)) {
                                int rc;

                                rc = flash_write((char *) ymodemBuf,
                                                  store_addr, res);
                                if (rc != 0) {
                                        flash_perror (rc);
                                        return (~0);
                                }
                        } else
#endif
                        {
                                memcpy((char *)(store_addr), ymodemBuf,
                                        res);
                        }

                }
        } else {
                printf("%s\n", xyzModem_error(err));
        }

        xyzModem_stream_close(&err);
        xyzModem_stream_terminate(false, &getcxmodem);


        flush_cache(offset, size);

        printf("## Total Size      = 0x%08x = %d Bytes\n", size, size);
        setenv_hex("filesize", size);

        return offset;
}

#endif

/* -------------------------------------------------------------------- */

#if defined(CONFIG_CMD_LOADS)

#ifdef  CONFIG_SYS_LOADS_BAUD_CHANGE
U_BOOT_CMD(
        loads, 3, 0,    do_load_serial,
        "load S-Record file over serial line",
        "[ off ] [ baud ]\n"
        "    - load S-Record file over serial line"
        " with offset 'off' and baudrate 'baud'"
);

#else   /* ! CONFIG_SYS_LOADS_BAUD_CHANGE */
U_BOOT_CMD(
        loads, 2, 0,    do_load_serial,
        "load S-Record file over serial line",
        "[ off ]\n"
        "    - load S-Record file over serial line with offset 'off'"
);
#endif  /* CONFIG_SYS_LOADS_BAUD_CHANGE */

/*
 * SAVES always requires LOADS support, but not vice versa
 */


#if defined(CONFIG_CMD_SAVES)
#ifdef  CONFIG_SYS_LOADS_BAUD_CHANGE
U_BOOT_CMD(
        saves, 4, 0,    do_save_serial,
        "save S-Record file over serial line",
        "[ off ] [size] [ baud ]\n"
        "    - save S-Record file over serial line"
        " with offset 'off', size 'size' and baudrate 'baud'"
);
#else   /* ! CONFIG_SYS_LOADS_BAUD_CHANGE */
U_BOOT_CMD(
        saves, 3, 0,    do_save_serial,
        "save S-Record file over serial line",
        "[ off ] [size]\n"
        "    - save S-Record file over serial line with offset 'off' and size 'size'"
);
#endif  /* CONFIG_SYS_LOADS_BAUD_CHANGE */
#endif  /* CONFIG_CMD_SAVES */
#endif  /* CONFIG_CMD_LOADS */


#if defined(CONFIG_CMD_LOADB)
U_BOOT_CMD(
        loadb, 3, 0,    do_load_serial_bin,
        "load binary file over serial line (kermit mode)",
        "[ off ] [ baud ]\n"
        "    - load binary file over serial line"
        " with offset 'off' and baudrate 'baud'"
);

U_BOOT_CMD(
        loadx, 3, 0,    do_load_serial_bin,
        "load binary file over serial line (xmodem mode)",
        "[ off ] [ baud ]\n"
        "    - load binary file over serial line"
        " with offset 'off' and baudrate 'baud'"
);

U_BOOT_CMD(
        loady, 3, 0,    do_load_serial_bin,
        "load binary file over serial line (ymodem mode)",
        "[ off ] [ baud ]\n"
        "    - load binary file over serial line"
        " with offset 'off' and baudrate 'baud'"
);

#endif  /* CONFIG_CMD_LOADB */

/* -------------------------------------------------------------------- */

#if defined(CONFIG_CMD_HWFLOW)
int do_hwflow(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
{
        extern int hwflow_onoff(int);

        if (argc == 2) {
                if (strcmp(argv[1], "off") == 0)
                        hwflow_onoff(-1);
                else
                        if (strcmp(argv[1], "on") == 0)
                                hwflow_onoff(1);
                        else
                                return CMD_RET_USAGE;
        }
        printf("RTS/CTS hardware flow control: %s\n", hwflow_onoff(0) ? "on" : "off");
        return 0;
}

/* -------------------------------------------------------------------- */

U_BOOT_CMD(
        hwflow, 2, 0,   do_hwflow,
        "turn RTS/CTS hardware flow control in serial line on/off",
        "[on|off]"
);

#endif  /* CONFIG_CMD_HWFLOW */