/* GRLIB APBUART Serial controller driver
 *
 * (C) Copyright 2008
 * Daniel Hellstrom, Gaisler Research, daniel@gaisler.com.
 *
 * 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 <asm/processor.h>
#include <asm/leon.h>
#include <serial.h>
#include <linux/compiler.h>

DECLARE_GLOBAL_DATA_PTR;

/* Force cache miss each time a serial controller reg is read */
#define CACHE_BYPASS 1

#ifdef CACHE_BYPASS
#define READ_BYTE(var)  SPARC_NOCACHE_READ_BYTE((unsigned int)&(var))
#define READ_HWORD(var) SPARC_NOCACHE_READ_HWORD((unsigned int)&(var))
#define READ_WORD(var)  SPARC_NOCACHE_READ((unsigned int)&(var))
#define READ_DWORD(var) SPARC_NOCACHE_READ_DWORD((unsigned int)&(var))
#endif

static int leon2_serial_init(void)
{
        LEON2_regs *leon2 = (LEON2_regs *) LEON2_PREGS;
        LEON2_Uart_regs *regs;
        unsigned int tmp;

        /* Init LEON2 UART
         *
         * Set scaler / baud rate
         *
         * Receiver & transmitter enable
         */
#if LEON2_CONSOLE_SELECT == LEON_CONSOLE_UART1
        regs = (LEON2_Uart_regs *) & leon2->UART_Channel_1;
#else
        regs = (LEON2_Uart_regs *) & leon2->UART_Channel_2;
#endif

        regs->UART_Scaler = CONFIG_SYS_LEON2_UART1_SCALER;

        /* Let bit 11 be unchanged (debug bit for GRMON) */
        tmp = READ_WORD(regs->UART_Control);

        regs->UART_Control = ((tmp & LEON2_UART_CTRL_DBG) |
                              (LEON2_UART1_LOOPBACK_ENABLE << 7) |
                              (LEON2_UART1_FLOWCTRL_ENABLE << 6) |
                              (LEON2_UART1_PARITY_ENABLE << 5) |
                              (LEON2_UART1_ODDPAR_ENABLE << 4) |
                              LEON2_UART_CTRL_RE | LEON2_UART_CTRL_TE);

        return 0;
}

static void leon2_serial_putc_raw(const char c)
{
        LEON2_regs *leon2 = (LEON2_regs *) LEON2_PREGS;
        LEON2_Uart_regs *regs;

#if LEON2_CONSOLE_SELECT == LEON_CONSOLE_UART1
        regs = (LEON2_Uart_regs *) & leon2->UART_Channel_1;
#else
        regs = (LEON2_Uart_regs *) & leon2->UART_Channel_2;
#endif

        /* Wait for last character to go. */
        while (!(READ_WORD(regs->UART_Status) & LEON2_UART_STAT_THE)) ;

        /* Send data */
        regs->UART_Channel = c;

#ifdef LEON_DEBUG
        /* Wait for data to be sent */
        while (!(READ_WORD(regs->UART_Status) & LEON2_UART_STAT_TSE)) ;
#endif
}

static void leon2_serial_putc(const char c)
{
        if (c == '\n')
                leon2_serial_putc_raw('\r');

        leon2_serial_putc_raw(c);
}

static int leon2_serial_getc(void)
{
        LEON2_regs *leon2 = (LEON2_regs *) LEON2_PREGS;
        LEON2_Uart_regs *regs;

#if LEON2_CONSOLE_SELECT == LEON_CONSOLE_UART1
        regs = (LEON2_Uart_regs *) & leon2->UART_Channel_1;
#else
        regs = (LEON2_Uart_regs *) & leon2->UART_Channel_2;
#endif

        /* Wait for a character to arrive. */
        while (!(READ_WORD(regs->UART_Status) & LEON2_UART_STAT_DR)) ;

        /* read data */
        return READ_WORD(regs->UART_Channel);
}

static int leon2_serial_tstc(void)
{
        LEON2_regs *leon2 = (LEON2_regs *) LEON2_PREGS;
        LEON2_Uart_regs *regs;

#if LEON2_CONSOLE_SELECT == LEON_CONSOLE_UART1
        regs = (LEON2_Uart_regs *) & leon2->UART_Channel_1;
#else
        regs = (LEON2_Uart_regs *) & leon2->UART_Channel_2;
#endif

        return (READ_WORD(regs->UART_Status) & LEON2_UART_STAT_DR);
}

/* set baud rate for uart */
static void leon2_serial_setbrg(void)
{
        /* update baud rate settings, read it from gd->baudrate */
        unsigned int scaler;
        LEON2_regs *leon2 = (LEON2_regs *) LEON2_PREGS;
        LEON2_Uart_regs *regs;

#if LEON2_CONSOLE_SELECT == LEON_CONSOLE_UART1
        regs = (LEON2_Uart_regs *) & leon2->UART_Channel_1;
#else
        regs = (LEON2_Uart_regs *) & leon2->UART_Channel_2;
#endif

        if (gd->baudrate > 0) {
                scaler =
                    (((CONFIG_SYS_CLK_FREQ * 10) / (gd->baudrate * 8)) -
                     5) / 10;
                regs->UART_Scaler = scaler;
        }
}

static struct serial_device leon2_serial_drv = {
        .name   = "leon2_serial",
        .start  = leon2_serial_init,
        .stop   = NULL,
        .setbrg = leon2_serial_setbrg,
        .putc   = leon2_serial_putc,
        .puts   = default_serial_puts,
        .getc   = leon2_serial_getc,
        .tstc   = leon2_serial_tstc,
};

void leon2_serial_initialize(void)
{
        serial_register(&leon2_serial_drv);
}

__weak struct serial_device *default_serial_console(void)
{
        return &leon2_serial_drv;
}