UART at U_BOOT

Hello Ranjith,

Apart from selecting serial console console configuration in the u-boot, some changes also need to be incorporated in the x-loader, such as:

• Enable UART4 Clocks: /board/omap3evm/omap3evm.c
• Set mux values accordingly: a/board/omap3evm/omap3evm.c
• Select serial console configuration: include/configs/omap3evm.h

Hope this helps.

Regards,

N.S.SriHarsha

Hello SriHarsha,

        I have done the change but i dint find any UART4 related clocks in board/ti/evm/evm.c . actually am working smartcard with UART at u-boot level.

Do i need to set or get any port attributes because i have a smart card application which is supported at kernel .i am patching the same application in u-boot so i am getting many errors in that .

Thanks,

Ranjith.

Hello Ranjith,

UART4 Clocks have to be enabled in the "per_clocks_enable" function of the x-loader sources.

Below attached is the snapshot.

Hey SriHarsha,

Thanks for your help .have you worked on smart cart on UART.

Thanks,

Ranjith.

Hey Ranjith,

I have not worked on it and may not be of any help.

Regards,

N.S.SriHarsha

Hello SriHarsha,

 i am trying to write and read the data to UART4 at the boot command that is u-boot after HIT any key to stop autoboot .so, can u help me how to write data in to UART4

actually am calling serial_init(); in common/main.c

which is calling driver/serial/serial.c

so,can u help me how to read and write.

Thanks,

Ranjith

Hello SriHarsha,

Could you please help UART4 at u-boot level how to write and read in u-boot.

Thanks,

Ranjith

Hi Ranjith,

We have used a custom driver for reading and writing. Below attached is the snapshot of the same.

For some reason, I'm not able to attach the C file.

/* includes */
#include <common.h>
#include "types.h"
#include "uart_drv.h"
#include "uart_utils.h"
#include "omap3530evm.h"

status_t uart_config(U8 uart_no, U16 baudrate, U8 data, U8 stop, U8 parity)
{
    U32 b = uart_base_addr[uart_no];

    uart_func_clk_en();

    switch (uart_no) {
    case UART1:
        mux_setup_uart1();
        break;

    case UART2:
        mux_setup_uart2();
        break;

    case UART3:
        /* Use the mux settings already set by the ROM code. */
        break;

    default:
        return FAILURE;
    }

    /* RESET OF UART */
    UART_REG_MDR1(b) = UART_RESET_MODE;
    while (UART_REG_MDR1(b) != UART_RESET_MODE) ;    /* wait for reset */

    /* UART CONFIGURATION */
    UART_REG_LCR(b) = 0xBF;
    UART_REG_EFR(b) |= (1 << 4);
    UART_REG_LCR(b) = (data | (stop << 2) | (parity << 3) | 0x80);
    UART_REG_MCR(b) = (1 << 6);
    UART_REG_TLR(b) = 0x00;
    UART_REG_FCR(b) = 0x87;    /* 56 byte RX FIFO and 8 byte TX FIFO */
    UART_REG_DLL(b) = (0xFF & uart_baudrate[baudrate]);
    UART_REG_DLH(b) = (0xFF & (uart_baudrate[baudrate] >> 8));

    UART_REG_LCR(b) &= 0x7F;
    UART_REG_IIR(b);
    UART_REG_IER(b) = 0x00;

    UART_REG_MDR1(b) = UART_MODE;

    return SUCCESS;
}

status_t uart_init(U8 uart_no, U8 parity)
{
    S32 ret_val = SUCCESS;

    uart_config(uart_no, UART_115200, UART_DATABITS_8, UART_STOPBITS_1, parity);

    return ret_val;
}

status_t uart_deinit(U8 uart_no)
{
    U32 b;

    b = uart_base_addr[uart_no];
    switch (UART_REG_MDR1(b) & 0x7) {    /* Get MDR1[2:0] */
    case UART_16X_MODE:
    case UART_16X_AUTO_BAUD:
    case UART_13X_MODE:
        /*
         ** Wait for the last transmitted bytes to leave the UART HW before
         ** deiniting (needed for reset after download).
         */
        while ((UART_REG_LSR(b) & (1 << 6) /*TX_SR_E */ ) == 0) ;
        break;
    default:
        break;
    }

    return SUCCESS;
}

static
void dg_serial_putc(U32 b, REG_U8 c)
{
    while ((UART_REG_LSR(b) & LSR_THR_EMPTY) == 0) ;
    UART_REG_THR(b) = c;
}

static
U8 dg_serial_getc(U32 b)
{
    while ((UART_REG_LSR(b) & LSR_DATA_READY) == 0) ;
    return (UART_REG_RHR(b));
}

S32 uart_read(U8 uart_no, U8 * buf, U32 size)
{
    U32 b = uart_base_addr[uart_no];
    U32 count;
    REG_U8 *pstr = buf;

    DEBUG("UART Num  = %d\n", uart_no);
    DEBUG("UART Base = 0x%X\n", b);

    for (count = 0; count < size; count++) {
        pstr[count] = dg_serial_getc(b);
    }

    return size;
}

S32 uart_write(U8 uart_no, U8 * buf, U32 size)
{
    U32 b = uart_base_addr[uart_no];
    U32 count;
    REG_U8 *pstr = buf;

    DEBUG("UART Num  = %d\n", uart_no);
    DEBUG("UART Base = 0x%X\n", b);

    for (count = 0; count < size; count++) {
        dg_serial_putc(b, pstr[count]);
    }

    return size;
}

Hope this helps.

Regards,

N.S.SriHarsha

Hello SriHarsha,

       Actually i am using the UART 1 for serial console configuration and UART 4 for Another purpose could you tell how use the UART 4 because if i am tring to do anything like

serial_init_uart()
{
        int clock_divisor;
        printf("My INITIALIZATION\n");
        #ifdef CONFIG_SYS_NS16550_COM4
        clock_divisor = calc_divisor(serial_ports[3]);
        NS16550_init(serial_ports[3], clock_divisor);
        printf("END OF INIT\N");
        _serial_putc('E',3);
        _serial_getc(3);
        #endif
}

Here i am calling my  own function but it is not setting the clock for UART 4 . can you help me out in this.

Thanks,

Ranjith.