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/*

 * UART driver used by OMAP devices

 *

 * Copyright (C) 2007 Bahadir Balban

 */

#include <libdev/uart.h>

#include <libdev/io.h>

#include "uart.h"

#define OMAP_UART_TXFE          0x20

void uart_tx_char(unsigned long uart_base, char c)

{

        volatile u32 reg;

        /* Check if there is space for tx */

        do {

                reg = read(uart_base + OMAP_UART_LSR);

        } while(!(reg & OMAP_UART_TXFE));

        write(c, uart_base + OMAP_UART_THR);

}

#define OMAP_UART_RXFNE                 0x1

#define OMAP_UART_RX_FIFO_STATUS        0x8

char uart_rx_char(unsigned long uart_base)

{

        volatile u32 reg;

        /* Check if pending data is there */

        do {

                reg = read(uart_base + OMAP_UART_LSR);

        } while(!(reg & OMAP_UART_RXFNE));

#if 0

        /* Check if there is some error in recieve */

        if(reg & OMAP_UART_RX_FIFO_STATUS)

                return -1;

#endif

        return (char)read(uart_base + OMAP_UART_RHR);

}

void uart_set_baudrate(unsigned long uart_base, u32 baudrate)

{

        u32 clk_div;

        /* 48Mhz clock fixed on beagleboard */

        const u32 clkrate = 48000000;

        /* If baud out of range, set default rate */

        if(baudrate > 3686400 || baudrate < 300)

                baudrate = 115200;

        clk_div = clkrate/(16 * baudrate);

        /* Set clockrate in DLH and DLL */

        write((clk_div & 0xff), uart_base + OMAP_UART_DLL);

        write(((clk_div >> 8) & 0xff ), uart_base + OMAP_UART_DLH);

}

void uart_init(unsigned long uart_base)

{

        /* Disable UART */

        uart_select_mode(uart_base, OMAP_UART_MODE_DEFAULT);

        /* Disable interrupts */

        uart_disable_interrupt(uart_base);

        /* Change to config mode, to set baud divisor */

        uart_set_link_control(uart_base, OMAP_UART_BANKED_MODE_CONFIG_A);

        /* Set the baud rate */

        uart_set_baudrate(uart_base, 115200);

        /* Switch to operational mode */

        uart_set_link_control(uart_base, OMAP_UART_BANKED_MODE_OPERATIONAL);

        /* Set up the link- parity, data bits stop bits to 8N1 */

        uart_disable_parity(uart_base);

        uart_set_data_bits(uart_base, OMAP_UART_DATA_BITS_8);

        uart_set_stop_bits(uart_base, OMAP_UART_STOP_BITS_1);

        /* Disable Fifos */

        uart_disable_fifo(uart_base);

        /* Enable modem Rx/Tx */

        uart_enable_tx(uart_base);

        uart_enable_rx(uart_base);

        /* Enable UART in 16x mode */

        uart_select_mode(uart_base, OMAP_UART_MODE_UART16X);

}

unsigned long uart_print_base;

void platform_init(void)

{

        uart_print_base = OMAP_UART_BASE;

        /*

         * We dont need to initialize uart here for variant-userspace,

         * as this is the same uart as used by kernel and hence

         * already initialized, we just need

         * a uart struct instance with proper base address.

         *

         * But in case of baremetal like loader, no one has done

         * initialization, so we need to do it.

         */

#if defined(VARIANT_BAREMETAL)

        uart_init(uart_print_base);

#endif

}