am33_serial.c

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//=============================================================================
//
//      am33_serial.c
//
//      Simple driver for the serial controllers on AM33 (MN103E) CPUs
//
//=============================================================================
//####ECOSGPLCOPYRIGHTBEGIN####
// -------------------------------------------
// This file is part of eCos, the Embedded Configurable Operating System.
// Copyright (C) 1998, 1999, 2000, 2001, 2002 Red Hat, Inc.
//
// eCos 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 or (at your option) any later version.
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// eCos 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 eCos; if not, write to the Free Software Foundation, Inc.,
// 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
//
// As a special exception, if other files instantiate templates or use macros
// or inline functions from this file, or you compile this file and link it
// with other works to produce a work based on this file, this file does not
// by itself cause the resulting work to be covered by the GNU General Public
// License. However the source code for this file must still be made available
// in accordance with section (3) of the GNU General Public License.
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// this file might be covered by the GNU General Public License.
//
// Alternative licenses for eCos may be arranged by contacting Red Hat, Inc.
// at http://sources.redhat.com/ecos/ecos-license/
// -------------------------------------------
//####ECOSGPLCOPYRIGHTEND####
//=============================================================================
//#####DESCRIPTIONBEGIN####
//
// Author(s):   dmoseley, dhowells
// Contributors:msalter
// Date:        2002-11-15
// Description: Simple driver for the AM33 UARTs
//
//####DESCRIPTIONEND####
//
//=============================================================================

#include <pkgconf/hal.h>
#include CYGBLD_HAL_TARGET_H
#include CYGBLD_HAL_PLATFORM_H

#include <cyg/hal/hal_arch.h>           // SAVE/RESTORE GP macros
#include <cyg/hal/hal_io.h>             // IO macros
#include <cyg/hal/hal_if.h>             // interface API
#include <cyg/hal/hal_intr.h>           // HAL_ENABLE/MASK/UNMASK_INTERRUPTS
#include <cyg/hal/hal_misc.h>           // Helper functions
#include <cyg/hal/drv_api.h>            // CYG_ISR_HANDLED

#if !defined(CYGSEM_HAL_AM33_PLF_USES_SERIAL0) && !defined(CYGSEM_HAL_AM33_PLF_USES_SERIAL1)
#define AM33_NUM_UARTS 0
#elif defined(CYGSEM_HAL_AM33_PLF_USES_SERIAL0) && defined(CYGSEM_HAL_AM33_PLF_USES_SERIAL1)
#define AM33_NUM_UARTS 2
#else
#define AM33_NUM_UARTS 1
#endif

#if AM33_NUM_UARTS > 0

//-----------------------------------------------------------------------------
// Base Registers
#define AM33_SER0_BASE      0xD4002000
#define AM33_SER1_BASE      0xD4002010

/*---------------------------------------------------------------------------*/
// AM33 Serial line

#define _SERIAL_CR       0x00
#define _SERIAL_ICR      0x04
#define _SERIAL_TXR      0x08
#define _SERIAL_RXR      0x09
#define _SERIAL_SR       0x0c

#define SERIAL0_CR       ((volatile cyg_uint16 *)(AM33_SER0_BASE + _SERIAL_CR))
#define SERIAL0_ICR      ((volatile cyg_uint8 *) (AM33_SER0_BASE + _SERIAL_ICR))
#define SERIAL0_TXR      ((volatile cyg_uint8 *) (AM33_SER0_BASE + _SERIAL_TXR))
#define SERIAL0_RXR      ((volatile cyg_uint8 *) (AM33_SER0_BASE + _SERIAL_RXR))
#define SERIAL0_SR       ((volatile cyg_uint16 *)(AM33_SER0_BASE + _SERIAL_SR))

#define SERIAL1_CR       ((volatile cyg_uint16 *)(AM33_SER1_BASE + _SERIAL_CR))
#define SERIAL1_ICR      ((volatile cyg_uint8 *) (AM33_SER1_BASE + _SERIAL_ICR))
#define SERIAL1_TXR      ((volatile cyg_uint8 *) (AM33_SER1_BASE + _SERIAL_TXR))
#define SERIAL1_RXR      ((volatile cyg_uint8 *) (AM33_SER1_BASE + _SERIAL_RXR))
#define SERIAL1_SR       ((volatile cyg_uint16 *)(AM33_SER1_BASE + _SERIAL_SR))

// Timer 0 provides a prescaler for lower baud rates
#define TIMER0_MD       ((volatile cyg_uint8 *)0xd4003000)
#define TIMER0_BR       ((volatile cyg_uint8 *)0xd4003010)

// Timer 2 provides baud rate divisor
#define TIMER2_MD       ((volatile cyg_uint8 *)0xd4003002)
#define TIMER2_BR       ((volatile cyg_uint8 *)0xd4003012)

// Timer 1 provides a prescaler for lower baud rates
#define TIMER1_MD       ((volatile cyg_uint8 *)0xd4003001)
#define TIMER1_BR       ((volatile cyg_uint8 *)0xd4003011)

// Timer 3 provides baud rate divisor
#define TIMER3_MD       ((volatile cyg_uint8 *)0xd4003003)
#define TIMER3_BR       ((volatile cyg_uint8 *)0xd4003013)

#define SIO_LSTAT_TRDY  0x20
#define SIO_LSTAT_RRDY  0x10

#define SIO_INT_ENABLE  0x11

#define TMR_ENABLE                   0x80
#define TMR_SRC_IOCLOCK              0x00
#define TMR_SRC_TMR0_UNDERFLOW       0x04


//-----------------------------------------------------------------------------

typedef struct {
    cyg_uint8* base;
    cyg_int32 msec_timeout;
    int isr_vector;
    cyg_int32 baud_rate;
} channel_data_t;

static channel_data_t channels[AM33_NUM_UARTS] = {
#if defined(CYGSEM_HAL_AM33_PLF_USES_SERIAL0) && !defined(HAL_PLATFORM_SERIAL1_FIRST)
    { (cyg_uint8*)AM33_SER0_BASE, 1000, CYGNUM_HAL_INTERRUPT_SERIAL_0_RX },
#endif
#ifdef CYGSEM_HAL_AM33_PLF_USES_SERIAL1
    { (cyg_uint8*)AM33_SER1_BASE, 1000, CYGNUM_HAL_INTERRUPT_SERIAL_1_RX },
#endif
#if defined(CYGSEM_HAL_AM33_PLF_USES_SERIAL0) && defined(HAL_PLATFORM_SERIAL1_FIRST)
    { (cyg_uint8*)AM33_SER0_BASE, 1000, CYGNUM_HAL_INTERRUPT_SERIAL_0_RX },
#endif
};

//-----------------------------------------------------------------------------
// Set the baud rate

static cyg_uint32
baud_divisor(int baud, int prescaler)
{
    cyg_uint32 divisor;

    // divisor == INT(IOCLK/baud/8 + 0.5)
    divisor = CYGHWR_HAL_MN10300_IOCLK_SPEED * 10;
    divisor /= (baud / 100);
    divisor /= prescaler;
    divisor /= 8;
    divisor += 500;
    divisor /= 1000;
    return divisor;
}

static int
cyg_hal_plf_serial_set_baud(cyg_uint8* port, cyg_uint32 baud_rate)
{
    volatile cyg_uint8 *timer_base_reg;
    volatile cyg_uint8 *timer_mode_reg;
    cyg_uint32 divisor, prescaler;

    if (port == (cyg_uint8*)AM33_SER0_BASE)
    {
        // SER0 uses TMR2
        timer_base_reg = TIMER2_BR;
        timer_mode_reg = TIMER2_MD;
    } else if (port == (cyg_uint8*)AM33_SER1_BASE) {
        // SER1 uses TMR3
        timer_base_reg = TIMER3_BR;
        timer_mode_reg = TIMER3_MD;
    } else {
        // Unknown port.
        return -1;
    }

    switch (baud_rate)
    {
    case 1200:
    case 2400:
    case 4800:
    case 9600:
    case 19200:
    case 38400:
    case 57600:
    case 115200:
    case 230400:
	break;

    default:
        // Unknown baud.  Don't change anything
        return -1;
    }

    for (prescaler = 1; prescaler <= 256; prescaler++) {
	divisor = baud_divisor(baud_rate, prescaler);
	if (divisor <= 256)
	    break;
    }
    --divisor;
    --prescaler;

    if (prescaler) {
	HAL_WRITE_UINT8(TIMER0_BR, prescaler);
	HAL_WRITE_UINT8(TIMER0_MD, TMR_ENABLE | TMR_SRC_IOCLOCK);
    } else {
	HAL_WRITE_UINT8(TIMER0_BR, 0);
	HAL_WRITE_UINT8(TIMER0_MD, 0);
    }

    HAL_WRITE_UINT8(timer_base_reg, divisor);
    HAL_WRITE_UINT8(timer_mode_reg, TMR_ENABLE |
		    (prescaler ? TMR_SRC_TMR0_UNDERFLOW : TMR_SRC_IOCLOCK));

    return 0;
}

//-----------------------------------------------------------------------------
// The minimal init, get and put functions. All by polling.

static void
cyg_hal_plf_serial_init_channel(void* __ch_data)
{
    cyg_uint8* port;

    // Some of the diagnostic print code calls through here with no idea what the ch_data is.
    // Go ahead and assume it is channels[0].
    if (__ch_data == 0)
      __ch_data = (void*)&channels[0];

    port = ((channel_data_t*)__ch_data)->base;

    // No interrupts for now.
    HAL_WRITE_UINT8(port + _SERIAL_ICR, 0x00);

    // Source from timer 2 or 3, 8bit chars, enable tx and rx
    HAL_WRITE_UINT16(port + _SERIAL_CR, 0xc085);
}

static void
cyg_hal_plf_serial_putc(void* __ch_data, cyg_uint8 __ch)
{
    cyg_uint8* port;
    cyg_uint16 _status;

    // Some of the diagnostic print code calls through here with no idea what the ch_data is.
    // Go ahead and assume it is channels[0].
    if (__ch_data == 0)
      __ch_data = (void*)&channels[0];

    port = ((channel_data_t*)__ch_data)->base;

    do {
        HAL_READ_UINT16(port + _SERIAL_SR, _status);
    } while ((_status & SIO_LSTAT_TRDY) != 0);

    HAL_WRITE_UINT8(port + _SERIAL_TXR, __ch);
}

static cyg_bool
cyg_hal_plf_serial_getc_nonblock(void* __ch_data, cyg_uint8* ch)
{
    cyg_uint8* port;
    cyg_uint8 _status;

    // Some of the diagnostic print code calls through here with no idea what the ch_data is.
    // Go ahead and assume it is channels[0].
    if (__ch_data == 0)
      __ch_data = (void*)&channels[0];

    port = ((channel_data_t*)__ch_data)->base;

    HAL_READ_UINT8(port + _SERIAL_SR, _status);
    if ((_status & SIO_LSTAT_RRDY) == 0)
        return false;

    HAL_READ_UINT8(port + _SERIAL_RXR, *ch);