/*
 * (C) Copyright 2004, Psyent Corporation <www.psyent.com>
 * Scott McNutt <smcnutt@psyent.com>
 *
 * YANU Support:
 * Copyright 2010, Renato Andreola <renato.andreola@imagos.it>
 *
 * See file CREDITS for list of people who contributed to this
 * project.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as
 * published by the Free Software Foundation; either version 2 of
 * the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
 * MA 02111-1307 USA
 */


#include <common.h>
#include <watchdog.h>
#include <asm/io.h>
#include <nios2-io.h>
#include <nios2-yanu.h>

DECLARE_GLOBAL_DATA_PTR;

/*------------------------------------------------------------------
 * JTAG acts as the serial port
 *-----------------------------------------------------------------*/
#if defined(CONFIG_CONSOLE_JTAG)

static nios_jtag_t *jtag = (nios_jtag_t *)CONFIG_SYS_NIOS_CONSOLE;

void serial_setbrg( void ){ return; }
int serial_init( void ) { return(0);}

void serial_putc (char c)
{
        unsigned val;

        while (NIOS_JTAG_WSPACE ( readl (&jtag->control)) == 0)
                WATCHDOG_RESET ();
        writel (&jtag->data, (unsigned char)c);
}

void serial_puts (const char *s)
{
        while (*s != 0)
                serial_putc (*s++);
}

int serial_tstc (void)
{
        return ( readl (&jtag->control) & NIOS_JTAG_RRDY);
}

int serial_getc (void)
{
        int c;
        unsigned val;

        while (1) {
                WATCHDOG_RESET ();
                val = readl (&jtag->data);
                if (val & NIOS_JTAG_RVALID)
                        break;
        }
        c = val & 0x0ff;
        return (c);
}

#elif defined(CONFIG_CONSOLE_YANU)
/*-----------------------------------------------------------------*/
/* YANU Imagos serial port */
/*-----------------------------------------------------------------*/

static yanu_uart_t *uart = (yanu_uart_t *)CONFIG_SYS_NIOS_CONSOLE;

#if defined(CONFIG_SYS_NIOS_FIXEDBAUD)

/* Everything's already setup for fixed-baud PTF assignment*/

void serial_setbrg (void)
{
        int n, k;
        const unsigned max_uns = 0xFFFFFFFF;
        unsigned best_n, best_m, baud;

        /* compute best N and M couple */
        best_n = YANU_MAX_PRESCALER_N;
        for (n = YANU_MAX_PRESCALER_N; n >= 0; n--) {
                if ((unsigned)CONFIG_SYS_CLK_FREQ / (1 << (n + 4)) >=
                    (unsigned)CONFIG_BAUDRATE) {
                        best_n = n;
                        break;
                }
        }
        for (k = 0;; k++) {
                if ((unsigned)CONFIG_BAUDRATE <= (max_uns >> (15+n-k)))
                        break;
        }
        best_m =
            ((unsigned)CONFIG_BAUDRATE * (1 << (15 + n - k))) /
            ((unsigned)CONFIG_SYS_CLK_FREQ >> k);

        baud = best_m + best_n * YANU_BAUDE;
        writel(&uart->baud, baud);

        return;
}

#else

void serial_setbrg (void)
{       
        int n, k;
        const unsigned max_uns = 0xFFFFFFFF;
        unsigned best_n, best_m, baud;

        /* compute best N and M couple */
        best_n = YANU_MAX_PRESCALER_N;
        for (n = YANU_MAX_PRESCALER_N; n >= 0; n--) {
                if ((unsigned)CONFIG_SYS_CLK_FREQ / (1 << (n + 4)) >=
                    gd->baudrate) {
                        best_n = n;
                        break;
                }
        }
        for (k = 0;; k++) {
                if (gd->baudrate <= (max_uns >> (15+n-k)))
                        break;
        }
        best_m =
            (gd->baudrate * (1 << (15 + n - k))) /
            ((unsigned)CONFIG_SYS_CLK_FREQ >> k);

        baud = best_m + best_n * YANU_BAUDE;
        writel(&uart->baud, baud);

        return;
}


#endif /* CONFIG_SYS_NIOS_FIXEDBAUD */

int serial_init (void)
{
        unsigned action,control;

        /* status register cleanup */
        action =  YANU_ACTION_RRRDY     |
                YANU_ACTION_RTRDY       |
                YANU_ACTION_ROE         |
                YANU_ACTION_RBRK        |
                YANU_ACTION_RFE         |
                YANU_ACTION_RPE         |
            YANU_ACTION_RFE | YANU_ACTION_RFIFO_CLEAR | YANU_ACTION_TFIFO_CLEAR;

        writel(&uart->action, action);
        
        /*  control register cleanup */
        /* no interrupts enabled */
        /* one stop bit */
        /* hardware flow control disabled */
        /* 8 bits */
        control = (0x7 << YANU_CONTROL_BITS_POS);
        /* enven parity just to be clean */
        control |= YANU_CONTROL_PAREVEN;
        /* we set threshold for fifo */
        control |= YANU_CONTROL_RDYDLY * YANU_RXFIFO_DLY;
        control |= YANU_CONTROL_TXTHR *  YANU_TXFIFO_THR;

        writel(&uart->control, control);

        /* to set baud rate */
        serial_setbrg();

        return (0);
}


/*-----------------------------------------------------------------------
 * YANU CONSOLE
 *---------------------------------------------------------------------*/
void serial_putc (char c)
{
        int tx_chars;
        unsigned status;

        if (c == '\n')
                serial_putc ('\r');
        
        while (1) {
                status = readl(&uart->status);
                tx_chars = (status>>YANU_TFIFO_CHARS_POS)
                        & ((1<<YANU_TFIFO_CHARS_N)-1);
                if (tx_chars < YANU_TXFIFO_SIZE-1)
                        break;
                WATCHDOG_RESET ();
        }

        writel(&uart->data, (unsigned char)c);
}

void serial_puts (const char *s)
{
        while (*s != 0) {
                serial_putc (*s++);
        }
}


int serial_tstc(void)
{
        unsigned status ;

        status = readl(&uart->status);
        return (((status >> YANU_RFIFO_CHARS_POS) &
                 ((1 << YANU_RFIFO_CHARS_N) - 1)) > 0);
}       

int serial_getc (void)
{
        while (serial_tstc() == 0)
                WATCHDOG_RESET ();
        
        /* first we pull the char */
        writel(&uart->action, YANU_ACTION_RFIFO_PULL);

        return(readl(&uart->data) & YANU_DATA_CHAR_MASK);
}

#else /*CONFIG_CONSOLE_YANU*/

/*------------------------------------------------------------------
 * UART the serial port
 *-----------------------------------------------------------------*/

static nios_uart_t *uart = (nios_uart_t *) CONFIG_SYS_NIOS_CONSOLE;

#if defined(CONFIG_SYS_NIOS_FIXEDBAUD)

/* Everything's already setup for fixed-baud PTF
 * assignment
 */
void serial_setbrg (void){ return; }
int serial_init (void) { return (0);}

#else

void serial_setbrg (void)
{
        unsigned div;

        div = (CONFIG_SYS_CLK_FREQ/gd->baudrate)-1;
        writel (&uart->divisor,div);
        return;
}

int serial_init (void)
{
        serial_setbrg ();
        return (0);
}

#endif /* CONFIG_SYS_NIOS_FIXEDBAUD */


/*-----------------------------------------------------------------------
 * UART CONSOLE
 *---------------------------------------------------------------------*/
void serial_putc (char c)
{
        if (c == '\n')
                serial_putc ('\r');
        while ((readl (&uart->status) & NIOS_UART_TRDY) == 0)
                WATCHDOG_RESET ();
        writel (&uart->txdata,(unsigned char)c);
}

void serial_puts (const char *s)
{
        while (*s != 0) {
                serial_putc (*s++);
        }
}

int serial_tstc (void)
{
        return (readl (&uart->status) & NIOS_UART_RRDY);
}

int serial_getc (void)
{
        while (serial_tstc () == 0)
                WATCHDOG_RESET ();
        return (readl (&uart->rxdata) & 0x00ff );
}

#endif /* CONFIG_JTAG_CONSOLE */