/******************************************************************************
 * @file     main.c
 * @version  V3.00
 * @brief
 *           Demonstrate how to implement a USB virtual COM port device.
 *           It supports one virtual COM port.
 * @note
 * @copyright SPDX-License-Identifier: Apache-2.0
 * @copyright Copyright (C) 2021 Nuvoton Technology Corp. All rights reserved.
 ******************************************************************************/
#include <stdio.h>
#include "NuMicro.h"
#include "cdc_serial.h"

/* If crystal-less is enabled, system won't use any crystal as clock source
   If using crystal-less, system will be 48MHz, otherwise, system is 72MHz
*/ 
#define CRYSTAL_LESS        1
#define HIRC_AUTO_TRIM      0x611   /* Use USB signal to fine tune HIRC 48MHz */
#define TRIM_INIT           (SYS_BASE+0x110)

/*--------------------------------------------------------------------------*/
STR_VCOM_LINE_CODING gLineCoding = {115200, 0, 0, 8};   /* Baud rate : 115200    */
/* Stop bit     */
/* parity       */
/* data bits    */
uint16_t gCtrlSignal = 0;     /* BIT0: DTR(Data Terminal Ready) , BIT1: RTS(Request To Send) */

/*--------------------------------------------------------------------------*/
#define RXBUFSIZE           512 /* RX buffer size */
#define TXBUFSIZE           512 /* RX buffer size */

#define TX_FIFO_SIZE        64  /* TX Hardware FIFO size */

/*---------------------------------------------------------------------------------------------------------*/
/* Global variables                                                                                        */
/*---------------------------------------------------------------------------------------------------------*/
/* UART0 */
volatile uint8_t comRbuf[RXBUFSIZE];
volatile uint16_t comRbytes = 0;
volatile uint16_t comRhead = 0;
volatile uint16_t comRtail = 0;

volatile uint8_t comTbuf[TXBUFSIZE];
volatile uint16_t comTbytes = 0;
volatile uint16_t comThead = 0;
volatile uint16_t comTtail = 0;

uint8_t gRxBuf[64] = {0};
volatile uint8_t *gpu8RxBuf = 0;
volatile uint32_t gu32RxSize = 0;
volatile uint32_t gu32TxSize = 0;

volatile int8_t gi8BulkOutReady = 0;

int IsDebugFifoEmpty(void);

void SYS_Init(void)
{
    /*---------------------------------------------------------------------------------------------------------*/
    /* Init System Clock                                                                                       */
    /*---------------------------------------------------------------------------------------------------------*/
    /* Enable HIRC clock */
    CLK_EnableXtalRC(CLK_PWRCTL_HIRCEN_Msk);

    /* Wait for HIRC clock ready */
    CLK_WaitClockReady(CLK_STATUS_HIRCSTB_Msk);

#if (!CRYSTAL_LESS)
    /* Enable GPIO Port F module clock */
    CLK_EnableModuleClock(GPIOF_MODULE);

    /* Set XT1_OUT(PF.2) and XT1_IN(PF.3) as input mode to use HXT */
    GPIO_SetMode(PF, BIT2|BIT3, GPIO_MODE_INPUT);

    /* Enable HXT clock */
    CLK_EnableXtalRC(CLK_PWRCTL_HXTEN_Msk);

    /* Wait for HXT clock ready */
    CLK_WaitClockReady(CLK_STATUS_HXTSTB_Msk);

    /* Set core clock to 72MHz */
    CLK_SetCoreClock(72000000);

    /* Select USB clock source as PLL and USB clock divider as 3 */
    CLK_SetModuleClock(USBD_MODULE, CLK_CLKSEL3_USBDSEL_PLL, CLK_CLKDIV0_USB(3));
#else
    /* Select HCLK clock source to HIRC and HCLK clock divider as 1 */
    CLK_SetHCLK(CLK_CLKSEL0_HCLKSEL_HIRC, CLK_CLKDIV0_HCLK(1));

    /* Select USB clock source as HIRC and USB clock divider as 1 */
    CLK_SetModuleClock(USBD_MODULE, CLK_CLKSEL3_USBDSEL_HIRC, CLK_CLKDIV0_USB(1));
#endif

    /* Enable UART0 module clock */
    CLK_EnableModuleClock(UART0_MODULE);

    /* Select UART0 module clock source as HIRC/2 and UART0 module clock divider as 1 */
    CLK_SetModuleClock(UART0_MODULE, CLK_CLKSEL1_UART0SEL_HIRC_DIV2, CLK_CLKDIV0_UART0(1));

    /* Enable USBD module clock */
    CLK_EnableModuleClock(USBD_MODULE);

    /*---------------------------------------------------------------------------------------------------------*/
    /* Init I/O Multi-function                                                                                 */
    /*---------------------------------------------------------------------------------------------------------*/
    /* Set PB multi-function pins for UART0 RXD and TXD */
    SYS->GPB_MFPH = (SYS->GPB_MFPH & (~(UART0_RXD_PB12_Msk | UART0_TXD_PB13_Msk))) | UART0_RXD_PB12 | UART0_TXD_PB13;
}

void UART0_Init(void)
{
    /*---------------------------------------------------------------------------------------------------------*/
    /* Init UART                                                                                               */
    /*---------------------------------------------------------------------------------------------------------*/
    /* Reset IP */
    SYS->IPRST1 |=  SYS_IPRST1_UART0RST_Msk;
    SYS->IPRST1 &= ~SYS_IPRST1_UART0RST_Msk;

    /* Configure UART0 and set UART0 Baudrate */
    UART0->BAUD = UART_BAUD_MODE2 | UART_BAUD_MODE2_DIVIDER((__HIRC >> 1), 115200);
    UART0->LINE = UART_WORD_LEN_8 | UART_PARITY_NONE | UART_STOP_BIT_1;

    UART0->INTEN = UART_INTEN_TOCNTEN_Msk | UART_INTEN_RDAIEN_Msk;
}



/*---------------------------------------------------------------------------------------------------------*/
/* UART Callback function                                                                                  */
/*---------------------------------------------------------------------------------------------------------*/
void UART0_IRQHandler(void)
{
    uint32_t u32IntStatus;
    uint8_t bInChar;
    int32_t size;

    u32IntStatus = UART0->INTSTS;

    if((u32IntStatus & 0x1 /* RDAIF */) || (u32IntStatus & 0x10 /* TOUT_IF */))
    {
        /* Receiver FIFO threshold level is reached or RX time out */

        /* Get all the input characters */
        while((UART0->FIFOSTS & UART_FIFOSTS_RXEMPTY_Msk) == 0)
        {
            /* Get the character from UART Buffer */
            bInChar = UART0->DAT;

            /* Check if buffer full */
            if(comRbytes < RXBUFSIZE)
            {
                /* Enqueue the character */
                comRbuf[comRtail++] = bInChar;
                if(comRtail >= RXBUFSIZE)
                    comRtail = 0;
                comRbytes++;
            }
            else
            {
                /* FIFO over run */
            }
        }
    }

    if(u32IntStatus & 0x2 /* THRE_IF */)
    {

        if(comTbytes && (UART0->INTEN & UART_INTEN_THREIEN_Msk))
        {
            /* Fill the TX FIFO */
            size = comTbytes;
            if(size >= TX_FIFO_SIZE)
            {
                size = TX_FIFO_SIZE;
            }

            while(size)
            {
                bInChar = comTbuf[comThead++];
                UART0->DAT = bInChar;
                if(comThead >= TXBUFSIZE)
                    comThead = 0;
                comTbytes--;
                size--;
            }
        }
        else
        {
            /* No more data, just stop TX (Stop work) */
            UART0->INTEN &= (~UART_INTEN_THREIEN_Msk);
        }
    }

}

void VCOM_TransferData(void)
{
    int32_t i, i32Len;

    /* Check whether USB is ready for next packet or not */
    if(gu32TxSize == 0)
    {
        /* Check whether we have new COM Rx data to send to USB or not */
        if(comRbytes)
        {
            i32Len = comRbytes;
            if(i32Len > EP2_MAX_PKT_SIZE)
                i32Len = EP2_MAX_PKT_SIZE;

            for(i = 0; i < i32Len; i++)
            {
                gRxBuf[i] = comRbuf[comRhead++];
                if(comRhead >= RXBUFSIZE)
                    comRhead = 0;
            }

            __set_PRIMASK(1);
            comRbytes -= i32Len;
            __set_PRIMASK(0);

            gu32TxSize = i32Len;
            USBD_MemCopy((uint8_t *)(USBD_BUF_BASE + USBD_GET_EP_BUF_ADDR(EP2)), (uint8_t *)gRxBuf, i32Len);
            USBD_SET_PAYLOAD_LEN(EP2, i32Len);
        }
        else
        {
            /* Prepare a zero packet if previous packet size is EP2_MAX_PKT_SIZE and
               no more data to send at this moment to note Host the transfer has been done */
            i32Len = USBD_GET_PAYLOAD_LEN(EP2);
            if(i32Len == EP2_MAX_PKT_SIZE)
                USBD_SET_PAYLOAD_LEN(EP2, 0);
        }
    }

    /* Process the Bulk out data when bulk out data is ready. */
    if(gi8BulkOutReady && (gu32RxSize <= TXBUFSIZE - comTbytes))
    {
        for(i = 0; i < gu32RxSize; i++)
        {
            comTbuf[comTtail++] = gpu8RxBuf[i];
            if(comTtail >= TXBUFSIZE)
                comTtail = 0;
        }

        __set_PRIMASK(1);
        comTbytes += gu32RxSize;
        __set_PRIMASK(0);

        gu32RxSize = 0;
        gi8BulkOutReady = 0; /* Clear bulk out ready flag */

        /* Ready to get next BULK out */
        USBD_SET_PAYLOAD_LEN(EP3, EP3_MAX_PKT_SIZE);
    }

    /* Process the software TX FIFO */
    if(comTbytes)
    {
        /* Check if TX is working */
        if((UART0->INTEN & UART_INTEN_THREIEN_Msk) == 0)
        {
            /* Send one bytes out */
            UART0->DAT = comTbuf[comThead++];
            if(comThead >= TXBUFSIZE)
                comThead = 0;

            comTbytes--;

            /* Enable TX Empty Interrupt. (Trigger first one) */
            UART0->INTEN |= UART_INTEN_THREIEN_Msk;
        }
    }
}

void PowerDown()
{
    /* Unlock protected registers */
    SYS_UnlockReg();

    printf("Enter power down ...\n");
    while(!IsDebugFifoEmpty());

    /* Wakeup Enable */
    USBD_ENABLE_INT(USBD_INTEN_WKEN_Msk);

    CLK_PowerDown();

    /* Clear PWR_DOWN_EN if it is not clear by itself */
    if(CLK->PWRCTL & CLK_PWRCTL_PDEN_Msk)
        CLK->PWRCTL ^= CLK_PWRCTL_PDEN_Msk;

    printf("device wakeup!\n");

    /* Lock protected registers */
    SYS_LockReg();
}

/*---------------------------------------------------------------------------------------------------------*/
/*  Main Function                                                                                          */
/*---------------------------------------------------------------------------------------------------------*/
int32_t main(void)
{
#if CRYSTAL_LESS
    uint32_t u32TrimInit;
#endif
    
    /* Unlock protected registers */
    SYS_UnlockReg();

    /* Init system and multi-funcition I/O */
    SYS_Init();

    /* Init UART for debug message */
    UART0_Init();

    printf("\n\n");
    printf("+------------------------------------------------------------+\n");
    printf("|          NuMicro USB Virtual COM Port Sample Code          |\n");
    printf("+------------------------------------------------------------+\n");
    printf("Set PB.12 as UART RX pin and PB.13 as UART TX pin\n");

    /* Open USB controller */
    USBD_Open(&gsInfo, VCOM_ClassRequest, NULL);

    /* Endpoint configuration */
    VCOM_Init();

    /* Start USB device */
    USBD_Start();

    /* Enable USB device interrupt */
    NVIC_EnableIRQ(USBD_IRQn);

#if CRYSTAL_LESS
    /* Backup default trim */
    u32TrimInit = M32(TRIM_INIT);
#endif

    /* Clear SOF */
    USBD->INTSTS = USBD_INTSTS_SOFIF_Msk;

    NVIC_EnableIRQ(UART0_IRQn);

    while(1)
    {
#if CRYSTAL_LESS
        /* Start USB trim if it is not enabled. */
        if((SYS->IRCTCTL & SYS_IRCTCTL_FREQSEL_Msk) != 1)
        {
            /* Start USB trim only when SOF */
            if(USBD->INTSTS & USBD_INTSTS_SOFIF_Msk)
            {
                /* Clear SOF */
                USBD->INTSTS = USBD_INTSTS_SOFIF_Msk;

                /* Re-enable crystal-less */
                SYS->IRCTCTL = HIRC_AUTO_TRIM | (8 << SYS_IRCTCTL_BOUNDARY_Pos);
            }
        }

        /* Disable USB Trim when error */
        if(SYS->IRCTISTS & (SYS_IRCTISTS_CLKERRIF_Msk | SYS_IRCTISTS_TFAILIF_Msk))
        {
            /* Init TRIM */
            M32(TRIM_INIT) = u32TrimInit;

            /* Disable crystal-less */
            SYS->IRCTCTL = 0;

            /* Clear error flags */
            SYS->IRCTISTS = SYS_IRCTISTS_CLKERRIF_Msk | SYS_IRCTISTS_TFAILIF_Msk;

            /* Clear SOF */
            USBD->INTSTS = USBD_INTSTS_SOFIF_Msk;
        }
#endif

        /* Enter power down when USB suspend */
        if(g_u8Suspend)
            PowerDown();

        VCOM_TransferData();
    }
}
