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/*

 * PL011 UART driver

 *

 * Copyright (C) 2009 B Labs Ltd.

 */

#include <libdev/uart.h>

#include <libdev/io.h>

#include "uart.h"

/* Error status bits in receive status register */

#define PL011_FE                (1 << 0)

#define PL011_PE                (1 << 1)

#define PL011_BE                (1 << 2)

#define PL011_OE                (1 << 3)

/* Status bits in flag register */

#define PL011_TXFE              (1 << 7)

#define PL011_RXFF              (1 << 6)

#define PL011_TXFF              (1 << 5)

#define PL011_RXFE              (1 << 4)

#define PL011_BUSY              (1 << 3)

#define PL011_DCD               (1 << 2)

#define PL011_DSR               (1 << 1)

#define PL011_CTS               (1 << 0)

void uart_tx_char(unsigned long base, char c)

{

        unsigned int val = 0;

        do {

                val = read((base + PL011_UARTFR));

        } while (val & PL011_TXFF);  /* TX FIFO FULL */

        write(c, (base + PL011_UARTDR));

}

char uart_rx_char(unsigned long base)

{

        unsigned int val = 0;

        do {

                val = read(base + PL011_UARTFR);

        } while (val & PL011_RXFE); /* RX FIFO Empty */

        return (char)read((base + PL011_UARTDR));

}

/*

 * Sets the baud rate in kbps. It is recommended to use

 * standard rates such as: 1200, 2400, 3600, 4800, 7200,

 * 9600, 14400, 19200, 28800, 38400, 57600 76800, 115200.

 */

void pl011_set_baudrate(unsigned long base, unsigned int baud,

                        unsigned int clkrate)

{

        const unsigned int uartclk = 24000000;  /* 24Mhz clock fixed on pb926 */

        unsigned int val = 0, ipart = 0, fpart = 0;

        /* Use default pb926 rate if no rate is supplied */

        if (clkrate == 0)

                clkrate = uartclk;

        if (baud > 115200 || baud < 1200)

                baud = 38400;   /* Default rate. */

        /* 24000000 / (38400 * 16) */

        ipart = 39;

        write(ipart, base + PL011_UARTIBRD);

        write(fpart, base + PL011_UARTFBRD);

        /*

         * For the IBAUD and FBAUD to update, we need to

         * write to UARTLCR_H because the 3 registers are

         * actually part of a single register in hardware

         * which only updates by a write to UARTLCR_H

         */

        val = read(base + PL011_UARTLCR_H);

        write(val, base + PL011_UARTLCR_H);

}

void uart_init(unsigned long uart_base)

{

        /* Initialise data register for 8 bit data read/writes */

        pl011_set_word_width(uart_base, 8);

        /*

         * Fifos are disabled because by default it is assumed the port

         * will be used as a user terminal, and in that case the typed

         * characters will only show up when fifos are flushed, rather than

         * when each character is typed. We avoid this by not using fifos.

         */

        pl011_disable_fifos(uart_base);

        /* Set default baud rate of 38400 */

        pl011_set_baudrate(uart_base, 38400, 24000000);

        /* Set default settings of 1 stop bit, no parity, no hw flow ctrl */

        pl011_set_stopbits(uart_base, 1);

        pl011_parity_disable(uart_base);

        /* Enable rx, tx, and uart chip */

        pl011_tx_enable(uart_base);

        pl011_rx_enable(uart_base);

        pl011_uart_enable(uart_base);

}

unsigned long uart_print_base;

void platform_init(void)

{

        uart_print_base = PL011_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

}