/*
 * Copyright (c) 2020-2021 Shanghai Panchip Microelectronics Co.,Ltd.
 *
 * SPDX-License-Identifier: Apache-2.0
 */

#include "uart_dfu.h"
#include "pan_uart.h"
#include "flash_manager.h"

#define XMODEM_UART			UART0
#define BAUDRATE			921600

#define SOH 0x01
#define STX 0x02
#define EOT 0x04
#define ACK 0x06
#define NAK 0x15
#define CAN 0x18
#define CTRLZ 0x1A
#define DLY_1S 2000
#define MAXRETRANS 25

static const unsigned short crc16_tab[256] = {
    0x0000, 0x1021, 0x2042, 0x3063, 0x4084, 0x50a5, 0x60c6, 0x70e7,
    0x8108, 0x9129, 0xa14a, 0xb16b, 0xc18c, 0xd1ad, 0xe1ce, 0xf1ef,
    0x1231, 0x0210, 0x3273, 0x2252, 0x52b5, 0x4294, 0x72f7, 0x62d6,
    0x9339, 0x8318, 0xb37b, 0xa35a, 0xd3bd, 0xc39c, 0xf3ff, 0xe3de,
    0x2462, 0x3443, 0x0420, 0x1401, 0x64e6, 0x74c7, 0x44a4, 0x5485,
    0xa56a, 0xb54b, 0x8528, 0x9509, 0xe5ee, 0xf5cf, 0xc5ac, 0xd58d,
    0x3653, 0x2672, 0x1611, 0x0630, 0x76d7, 0x66f6, 0x5695, 0x46b4,
    0xb75b, 0xa77a, 0x9719, 0x8738, 0xf7df, 0xe7fe, 0xd79d, 0xc7bc,
    0x48c4, 0x58e5, 0x6886, 0x78a7, 0x0840, 0x1861, 0x2802, 0x3823,
    0xc9cc, 0xd9ed, 0xe98e, 0xf9af, 0x8948, 0x9969, 0xa90a, 0xb92b,
    0x5af5, 0x4ad4, 0x7ab7, 0x6a96, 0x1a71, 0x0a50, 0x3a33, 0x2a12,
    0xdbfd, 0xcbdc, 0xfbbf, 0xeb9e, 0x9b79, 0x8b58, 0xbb3b, 0xab1a,
    0x6ca6, 0x7c87, 0x4ce4, 0x5cc5, 0x2c22, 0x3c03, 0x0c60, 0x1c41,
    0xedae, 0xfd8f, 0xcdec, 0xddcd, 0xad2a, 0xbd0b, 0x8d68, 0x9d49,
    0x7e97, 0x6eb6, 0x5ed5, 0x4ef4, 0x3e13, 0x2e32, 0x1e51, 0x0e70,
    0xff9f, 0xefbe, 0xdfdd, 0xcffc, 0xbf1b, 0xaf3a, 0x9f59, 0x8f78,
    0x9188, 0x81a9, 0xb1ca, 0xa1eb, 0xd10c, 0xc12d, 0xf14e, 0xe16f,
    0x1080, 0x00a1, 0x30c2, 0x20e3, 0x5004, 0x4025, 0x7046, 0x6067,
    0x83b9, 0x9398, 0xa3fb, 0xb3da, 0xc33d, 0xd31c, 0xe37f, 0xf35e,
    0x02b1, 0x1290, 0x22f3, 0x32d2, 0x4235, 0x5214, 0x6277, 0x7256,
    0xb5ea, 0xa5cb, 0x95a8, 0x8589, 0xf56e, 0xe54f, 0xd52c, 0xc50d,
    0x34e2, 0x24c3, 0x14a0, 0x0481, 0x7466, 0x6447, 0x5424, 0x4405,
    0xa7db, 0xb7fa, 0x8799, 0x97b8, 0xe75f, 0xf77e, 0xc71d, 0xd73c,
    0x26d3, 0x36f2, 0x0691, 0x16b0, 0x6657, 0x7676, 0x4615, 0x5634,
    0xd94c, 0xc96d, 0xf90e, 0xe92f, 0x99c8, 0x89e9, 0xb98a, 0xa9ab,
    0x5844, 0x4865, 0x7806, 0x6827, 0x18c0, 0x08e1, 0x3882, 0x28a3,
    0xcb7d, 0xdb5c, 0xeb3f, 0xfb1e, 0x8bf9, 0x9bd8, 0xabbb, 0xbb9a,
    0x4a75, 0x5a54, 0x6a37, 0x7a16, 0x0af1, 0x1ad0, 0x2ab3, 0x3a92,
    0xfd2e, 0xed0f, 0xdd6c, 0xcd4d, 0xbdaa, 0xad8b, 0x9de8, 0x8dc9,
    0x7c26, 0x6c07, 0x5c64, 0x4c45, 0x3ca2, 0x2c83, 0x1ce0, 0x0cc1,
    0xef1f, 0xff3e, 0xcf5d, 0xdf7c, 0xaf9b, 0xbfba, 0x8fd9, 0x9ff8,
    0x6e17, 0x7e36, 0x4e55, 0x5e74, 0x2e93, 0x3eb2, 0x0ed1, 0x1ef0};

static unsigned short crc16_ccitt(const unsigned char *xbuff, int len)
{
    register int i;
    register unsigned short CRC = 0x00;
    for (i = 0; i < len; i++)
    {
        CRC = (CRC << 8) ^ crc16_tab[((CRC >> 8) ^ *xbuff++) & 0xff];
    }
    return CRC;
}


static void _outbyte(int c)
{
    while (UART_IsTxFifoFull(XMODEM_UART));
    XMODEM_UART->RBR_THR_DLL = c;
}

void outbyte(int c)
{
    static char prev = 0;
    if (c < ' ' && c != '\r' && c != '\n' && c != '\t' && c != '\b')
        return;
    if (c == '\n' && prev != '\r')
        _outbyte('\r');
    _outbyte(c);
    prev = c;
}

static int _inbyte(unsigned short timeout)
{
    unsigned short c;
    uint32_t timeoutt;
    timeoutt = ((uint32_t)timeout) << 6;
    while (1)
    {
        if ((XMODEM_UART->USR & UART_USR_RFNE_Msk))
        {
            break;
        }
        timeoutt--;
        if (timeoutt == 0)
        {
            return -2;
        }
    }
    c = XMODEM_UART->RBR_THR_DLL;
    return c;
}

static int check(int crc, const unsigned char *buf, int sz)
{
    if (crc)
    {
        unsigned short crc = crc16_ccitt(buf, sz);
        unsigned short tcrc = (buf[sz] << 8) + buf[sz + 1];
        if (crc == tcrc)
            return 1;
    }
    else
    {
        int i;
        unsigned char cks = 0;
        for (i = 0; i < sz; ++i)
        {
            cks += buf[i];
        }
        if (cks == buf[sz])
            return 1;
    }

    return 0;
}

RAM_FUNC static int xmodemReceive(uint32_t addr) 
{
    unsigned char xbuff[1030]; /* 1024 for XModem 1k + 3 head chars + 2 crc + nul */
    unsigned char *p;
    int bufsz, crc = 0;
    unsigned char trychar = 'C';
    unsigned char packetno = 1;
    int i, c, len = 0;
    uint32_t dfu_addr;
    int retry, retrans = MAXRETRANS;
    dfu_addr = addr;

    for (; ;)
    {
        for (retry = 0; retry < 2; ++retry)
        {
            if (trychar)
                _outbyte(trychar);
            if ((c = _inbyte((DLY_1S) << 1)) >= 0)
            {
                switch (c)
                {
                case SOH:
                    bufsz = 128;
                    goto start_recv;
                case STX:
                    bufsz = 1024;
                    goto start_recv;
                case EOT:
                    _outbyte(ACK);
                    return len; /* normal end */
                case CAN:
                    if ((c = _inbyte(DLY_1S)) == CAN)
                    {
                        _outbyte(ACK);
                        return -1; /* canceled by remote */
                    }
                    break;
                default:
                    break;
                }
            }

        }
        if (trychar == 'C')
        {
            trychar = NAK;
            continue;
        }

        _outbyte(CAN);
        _outbyte(CAN);
        _outbyte(CAN);

        return -2; /* sync error */

    start_recv:
        if (trychar == 'C')
            crc = 1;
        trychar = 0;
        p = xbuff;
        *p++ = c;
        for (i = 0; i < (bufsz + (crc ? 1 : 0) + 3); ++i)
        {
            if ((c = _inbyte(DLY_1S)) < 0)
                goto reject;
            *p++ = c;
        }

        if (xbuff[1] == (unsigned char)(~xbuff[2]) &&
            (xbuff[1] == packetno || xbuff[1] == (unsigned char)packetno - 1) &&
            check(crc, &xbuff[3], bufsz))
        {
            if (xbuff[1] == packetno)
            {
                fm_write_flash(dfu_addr + len, &xbuff[3], bufsz);
            }
            len += bufsz;
            ++packetno;
            retrans = MAXRETRANS + 1;

            if (--retrans <= 0)
            {
                _outbyte(CAN);
                _outbyte(CAN);
                _outbyte(CAN);
                return -3; /* too many retry error */
            }
            _outbyte(ACK);
            continue;
        }
    reject:
        _outbyte(NAK);
    }
}
#if FALSE
int xmodemTransmit(unsigned char *src, int srcsz)
{
    unsigned char xbuff[1030]; /* 1024 for XModem 1k + 3 head chars + 2 crc + nul */
    int bufsz, crc = -1;
    unsigned char packetno = 1;
    int i, c, len = 0;
    int retry;

    for (;;)
    {
        for (retry = 0; retry < 16; ++retry)
        {
            if ((c = _inbyte((DLY_1S) << 1)) >= 0)
            {
                switch (c)
                {
                case 'C':
                    crc = 1;
                    goto start_trans;
                case NAK:
                    crc = 0;
                    goto start_trans;
                case CAN:
                    if ((c = _inbyte(DLY_1S)) == CAN)
                    {
                        _outbyte(ACK);
                        return -1; /* canceled by remote */
                    }
                    break;
                default:
                    break;
                }
            }
        }
        _outbyte(CAN);
        _outbyte(CAN);
        _outbyte(CAN);
        return -2; /* no sync */

        for (;;)
        {
        start_trans:
            xbuff[0] = SOH;
            bufsz = 128;
            xbuff[1] = packetno;
            xbuff[2] = ~packetno;
            c = srcsz - len;
            if (c > bufsz)
                c = bufsz;
            if (c >= 0)
            {
                memset(&xbuff[3], 0, bufsz);
                if (c == 0)
                {
                    xbuff[3] = CTRLZ;
                }
                else
                {
                    memcpy(&xbuff[3], &src[len], c);
                    if (c < bufsz)
                        xbuff[3 + c] = CTRLZ;
                }
                if (crc)
                {
                    unsigned short ccrc = crc16_ccitt(&xbuff[3], bufsz);
                    xbuff[bufsz + 3] = (ccrc >> 8) & 0xFF;
                    xbuff[bufsz + 4] = ccrc & 0xFF;
                }
                else
                {
                    unsigned char ccks = 0;
                    for (i = 3; i < bufsz + 3; ++i)
                    {
                        ccks += xbuff[i];
                    }
                    xbuff[bufsz + 3] = ccks;
                }
                for (retry = 0; retry < MAXRETRANS; ++retry)
                {
                    for (i = 0; i < bufsz + 4 + (crc ? 1 : 0); ++i)
                    {
                        _outbyte(xbuff[i]);
                    }
                    if ((c = _inbyte(DLY_1S)) >= 0)
                    {
                        switch (c)
                        {
                        case ACK:
                            ++packetno;
                            len += bufsz;
                            goto start_trans;
                        case CAN:
                            if ((c = _inbyte(DLY_1S)) == CAN)
                            {
                                _outbyte(ACK);
                                return -1; /* canceled by remote */
                            }
                            break;
                        case NAK:
                        default:
                            break;
                        }
                    }
                }
                _outbyte(CAN);
                _outbyte(CAN);
                _outbyte(CAN);
                return -4; /* xmit error */
            }
            else
            {
                for (retry = 0; retry < 10; ++retry)
                {
                    _outbyte(EOT);
                    if ((c = _inbyte((DLY_1S) << 1)) == ACK)
                        break;
                }
                return (c == ACK) ? len : -5;
            }
        }
    }
}
#endif
static void uart_device_init(void)
{
	CLK_AHBPeriphClockCmd(CLK_AHBPeriph_APB1, ENABLE);
    CLK_APB1PeriphClockCmd(CLK_APB1Periph_UART0, ENABLE);
	
    SYS_SET_MFP(P1, 6, UART0_TX);
    SYS_SET_MFP(P1, 7, UART0_RX);
    GPIO_EnableDigitalPath(P1, BIT7);

    UART_InitTypeDef Init_Struct;

    Init_Struct.UART_BaudRate = BAUDRATE;
    Init_Struct.UART_LineCtrl = Uart_Line_8n1;
	
    /* Init UART0 for printf */
    UART_Init(UART0, &Init_Struct);
    UART_EnableFifo(UART0);
}
 
void on_uart_dfu_enter(void)
{
	int rc;
	
	fm_status_refresh(); /* clear flash manager for a new ota process */
	uart_device_init();
	while (1) {
		rc = xmodemReceive(FLASH_AREA_IMAGE_START);

        if (rc > 1024) { /* receive image info */
			if (!fm_image_completed_check(FLASH_AREA_IMAGE_START)) { /* check image */ 
				fm_image_make_invalid(FLASH_AREA_IMAGE_START);
			}
			SYS_UnlockReg();
            CLK_ResetChip();
			SYS_LockReg();
        }
		SYS_delay_10nop(1000000);
	}
	
}