Subversion Repositories openrisc_2011-10-31

//==========================================================================

//

//      atlas_serial.c

//

//      Serial device driver for ATLAS on-chip serial devices

//

//==========================================================================

//####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

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// for more details.

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//

// 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

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//####ECOSGPLCOPYRIGHTEND####

//==========================================================================

//#####DESCRIPTIONBEGIN####

//

// Author(s):   dmoseley, based on POWERPC driver by jskov

// Contributors: gthomas, jskov, dmoseley

// Date:        2000-06-23

// Purpose:     ATLAS serial device driver

// Description: ATLAS serial device driver

//

// To Do:

//   Put in magic to effectively use the FIFOs. Transmitter FIFO fill is a

//   problem, and setting receiver FIFO interrupts to happen only after

//   n chars may conflict with hal diag.

//

//####DESCRIPTIONEND####

//

//==========================================================================

#include <pkgconf/io_serial.h>

#include <pkgconf/io.h>

#include <cyg/io/io.h>

#include <cyg/hal/hal_intr.h>

#include <cyg/io/devtab.h>

#include <cyg/infra/diag.h>

#include <cyg/io/serial.h>

#ifdef CYGPKG_IO_SERIAL_MIPS_ATLAS

#include "atlas_serial.h"

typedef struct atlas_serial_info {

    CYG_ADDRWORD   base;

    CYG_WORD       int_num;

    cyg_interrupt  serial_interrupt;

    cyg_handle_t   serial_interrupt_handle;

    cyg_uint8      iir;

} atlas_serial_info;

static bool atlas_serial_init(struct cyg_devtab_entry *tab);

static bool atlas_serial_putc(serial_channel *chan, unsigned char c);

static Cyg_ErrNo atlas_serial_lookup(struct cyg_devtab_entry **tab,

                                   struct cyg_devtab_entry *sub_tab,

                                   const char *name);

static unsigned char atlas_serial_getc(serial_channel *chan);

static Cyg_ErrNo atlas_serial_set_config(serial_channel *chan, cyg_uint32 key,

                                         const void *xbuf, cyg_uint32 *len);

static void atlas_serial_start_xmit(serial_channel *chan);

static void atlas_serial_stop_xmit(serial_channel *chan);

static cyg_uint32 atlas_serial_ISR(cyg_vector_t vector, cyg_addrword_t data);

static void       atlas_serial_DSR(cyg_vector_t vector, cyg_ucount32 count, cyg_addrword_t data);

static SERIAL_FUNS(atlas_serial_funs,

                   atlas_serial_putc,

                   atlas_serial_getc,

                   atlas_serial_set_config,

                   atlas_serial_start_xmit,

                   atlas_serial_stop_xmit

    );

static atlas_serial_info atlas_serial_info0 ={ATLAS_SER_16550_BASE_A,

                                              CYGNUM_HAL_INTERRUPT_SER};

#if CYGNUM_IO_SERIAL_MIPS_ATLAS_SERIAL_A_BUFSIZE > 0

static unsigned char atlas_serial_out_buf0[CYGNUM_IO_SERIAL_MIPS_ATLAS_SERIAL_A_BUFSIZE];

static unsigned char atlas_serial_in_buf0[CYGNUM_IO_SERIAL_MIPS_ATLAS_SERIAL_A_BUFSIZE];

static SERIAL_CHANNEL_USING_INTERRUPTS(atlas_serial_channel0,

                                       atlas_serial_funs,

                                       atlas_serial_info0,

                                       CYG_SERIAL_BAUD_RATE(CYGNUM_IO_SERIAL_MIPS_ATLAS_SERIAL_A_BAUD),

                                       CYG_SERIAL_STOP_DEFAULT,

                                       CYG_SERIAL_PARITY_DEFAULT,

                                       CYG_SERIAL_WORD_LENGTH_DEFAULT,

                                       CYG_SERIAL_FLAGS_DEFAULT,

                                       &atlas_serial_out_buf0[0],

                                       sizeof(atlas_serial_out_buf0),

                                       &atlas_serial_in_buf0[0],

                                       sizeof(atlas_serial_in_buf0)

    );

#else

static SERIAL_CHANNEL(atlas_serial_channel0,

                      atlas_serial_funs,

                      atlas_serial_info0,

                      CYG_SERIAL_BAUD_RATE(CYGNUM_IO_SERIAL_MIPS_ATLAS_SERIAL_A_BAUD),

                      CYG_SERIAL_STOP_DEFAULT,

                      CYG_SERIAL_PARITY_DEFAULT,

                      CYG_SERIAL_WORD_LENGTH_DEFAULT,

                      CYG_SERIAL_FLAGS_DEFAULT

    );

#endif

DEVTAB_ENTRY(atlas_serial_io0,

             CYGDAT_IO_SERIAL_MIPS_ATLAS_SERIAL_A_NAME,

             0,                 // Does not depend on a lower level interface

             &cyg_io_serial_devio,

             atlas_serial_init,

             atlas_serial_lookup,     // Serial driver may need initializing

             &atlas_serial_channel0

    );

// Internal function to actually configure the hardware to desired baud rate, etc.

static bool

atlas_serial_config_port(serial_channel *chan, cyg_serial_info_t *new_config, bool init)

{

    atlas_serial_info *atlas_chan = (atlas_serial_info *)chan->dev_priv;

    cyg_addrword_t port = atlas_chan->base;

    cyg_uint16 baud_divisor = select_baud[new_config->baud];

    cyg_uint8 _lcr, _ier;

    if (baud_divisor == 0)

        return false;    // Invalid baud rate selected

    //

    // We may need to increase the timeout before causing a break reset.

    // According to the Atlas Users Manual (Document MD00005) The BRKRES

    // register will need to be programmed with a value larger that 0xA (the default)

    // if we are going to use a baud rate lower than 2400.

    //

    if (new_config->baud <= CYGNUM_SERIAL_BAUD_2400)

    {

        // For now, just disable the break reset entirely.

        HAL_WRITE_UINT32(HAL_ATLAS_BRKRES, 0);

    } else {

        // Put the break reset state back to the default

        HAL_WRITE_UINT32(HAL_ATLAS_BRKRES, HAL_ATLAS_BRKRES_DEFAULT_VALUE);

    }

    // Disable port interrupts while changing hardware

    HAL_READ_UINT8(port+SER_16550_IER, _ier);

    HAL_WRITE_UINT8(port+SER_16550_IER, 0);

    // Set databits, stopbits and parity.

    _lcr = select_word_length[(new_config->word_length -

                               CYGNUM_SERIAL_WORD_LENGTH_5)] |

        select_stop_bits[new_config->stop] |

        select_parity[new_config->parity];

    HAL_WRITE_UINT8(port+SER_16550_LCR, _lcr);

    // Set baud rate.

    _lcr |= LCR_DL;

    HAL_WRITE_UINT8(port+SER_16550_LCR, _lcr);

    HAL_WRITE_UINT8(port+SER_16550_DLM, baud_divisor >> 8);

    HAL_WRITE_UINT8(port+SER_16550_DLL, baud_divisor & 0xff);

    _lcr &= ~LCR_DL;

    HAL_WRITE_UINT8(port+SER_16550_LCR, _lcr);

    if (init) {

        // Enable and clear FIFO

        HAL_WRITE_UINT8(port+SER_16550_FCR,

                        (FCR_ENABLE | FCR_CLEAR_RCVR | FCR_CLEAR_XMIT));

        if (chan->out_cbuf.len != 0) {

            HAL_WRITE_UINT8(port+SER_16550_IER, SIO_IER_ERDAI);

        } else {

            HAL_WRITE_UINT8(port+SER_16550_IER, 0);

        }

    } else {

        HAL_WRITE_UINT8(port+SER_16550_IER, _ier);

    }

    if (new_config != &chan->config) {

        chan->config = *new_config;

    }

    return true;

}

// Function to initialize the device.  Called at bootstrap time.

static bool

atlas_serial_init(struct cyg_devtab_entry *tab)

{

    serial_channel *chan = (serial_channel *)tab->priv;

    atlas_serial_info *atlas_chan = (atlas_serial_info *)chan->dev_priv;

#ifdef CYGDBG_IO_INIT

    diag_printf("ATLAS SERIAL init - dev: %x.%d\n", atlas_chan->base, atlas_chan->int_num);

#endif

    (chan->callbacks->serial_init)(chan);  // Really only required for interrupt driven devices

    if (chan->out_cbuf.len != 0) {

        cyg_drv_interrupt_create(atlas_chan->int_num,

                                 0,         // can change IRQ0 priority

                                 (cyg_addrword_t)chan,   //  Data item passed to interrupt handler

                                 atlas_serial_ISR,

                                 atlas_serial_DSR,

                                 &atlas_chan->serial_interrupt_handle,

                                 &atlas_chan->serial_interrupt);

        cyg_drv_interrupt_attach(atlas_chan->serial_interrupt_handle);

        cyg_drv_interrupt_unmask(atlas_chan->int_num);

    }

    atlas_serial_config_port(chan, &chan->config, true);

    return true;

}

// This routine is called when the device is "looked" up (i.e. attached)

static Cyg_ErrNo

atlas_serial_lookup(struct cyg_devtab_entry **tab,

                  struct cyg_devtab_entry *sub_tab,

                  const char *name)

{

    serial_channel *chan = (serial_channel *)(*tab)->priv;

    (chan->callbacks->serial_init)(chan);  // Really only required for interrupt driven devices

    return ENOERR;

}

// Send a character to the device output buffer.

// Return 'true' if character is sent to device

static bool

atlas_serial_putc(serial_channel *chan, unsigned char c)

{

    atlas_serial_info *atlas_chan = (atlas_serial_info *)chan->dev_priv;

    cyg_addrword_t port = atlas_chan->base;

    cyg_uint8 _lsr;

    HAL_READ_UINT8(port+SER_16550_LSR, _lsr);

    if (_lsr & SIO_LSR_THRE) {

        // Transmit buffer is empty

        HAL_WRITE_UINT8(port+SER_16550_THR, c);

        return true;

    } else {

        // No space

        return false;

    }

}

// Fetch a character from the device input buffer, waiting if necessary

static unsigned char

atlas_serial_getc(serial_channel *chan)

{

    unsigned char c;

    atlas_serial_info *atlas_chan = (atlas_serial_info *)chan->dev_priv;

    cyg_addrword_t port = atlas_chan->base;

    cyg_uint8 _lsr;

    do {

        HAL_READ_UINT8(port+SER_16550_LSR, _lsr);

    } while ((_lsr & SIO_LSR_DR) == 0);

    HAL_READ_UINT8(port+SER_16550_RBR, c);

    return c;

}

// Set up the device characteristics; baud rate, etc.

static Cyg_ErrNo

atlas_serial_set_config(serial_channel *chan, cyg_uint32 key,

                        const void *xbuf, cyg_uint32 *len)

{

    switch (key) {

    case CYG_IO_SET_CONFIG_SERIAL_INFO:

      {

        cyg_serial_info_t *config = (cyg_serial_info_t *)xbuf;

        if ( *len < sizeof(cyg_serial_info_t) ) {

            return -EINVAL;

        }

        *len = sizeof(cyg_serial_info_t);

        if ( true != atlas_serial_config_port(chan, config, false) )

            return -EINVAL;

      }

      break;

    default:

        return -EINVAL;

    }

    return ENOERR;

}

// Enable the transmitter on the device

static void

atlas_serial_start_xmit(serial_channel *chan)

{

    atlas_serial_info *atlas_chan = (atlas_serial_info *)chan->dev_priv;

    cyg_addrword_t port = atlas_chan->base;

    cyg_uint8 _ier;

    HAL_READ_UINT8(port+SER_16550_IER, _ier);

    _ier |= IER_XMT;                    // Enable xmit interrupt

    HAL_WRITE_UINT8(port+SER_16550_IER, _ier);

    // We should not need to call this here.  THRE Interrupts are enabled, and the DSR

    // below calls this function.  However, sometimes we get called with Master Interrupts

    // disabled, and thus the DSR never runs.  This is unfortunate because it means we

    // will be doing multiple processing steps for the same thing.

    (chan->callbacks->xmt_char)(chan);

}

// Disable the transmitter on the device

static void

atlas_serial_stop_xmit(serial_channel *chan)

{

    atlas_serial_info *atlas_chan = (atlas_serial_info *)chan->dev_priv;

    cyg_addrword_t port = atlas_chan->base;

    cyg_uint8 _ier;

    HAL_READ_UINT8(port+SER_16550_IER, _ier);

    _ier &= ~IER_XMT;                   // Disable xmit interrupt

    HAL_WRITE_UINT8(port+SER_16550_IER, _ier);

}

// Serial I/O - low level interrupt handler (ISR)

static cyg_uint32

atlas_serial_ISR(cyg_vector_t vector, cyg_addrword_t data)

{

    serial_channel *chan = (serial_channel *)data;

    atlas_serial_info *atlas_chan = (atlas_serial_info *)chan->dev_priv;

    cyg_drv_interrupt_mask(atlas_chan->int_num);

    cyg_drv_interrupt_acknowledge(atlas_chan->int_num);

    return CYG_ISR_CALL_DSR;  // Cause DSR to be run

}

// Serial I/O - high level interrupt handler (DSR)

static void

atlas_serial_DSR(cyg_vector_t vector, cyg_ucount32 count, cyg_addrword_t data)

{

    serial_channel *chan = (serial_channel *)data;

    atlas_serial_info *atlas_chan = (atlas_serial_info *)chan->dev_priv;

    cyg_addrword_t port = atlas_chan->base;

    cyg_uint8 _iir;

    HAL_READ_UINT8(port+SER_16550_IIR, _iir);

    _iir &= SIO_IIR_ID_MASK;

    if ( ISR_Tx_Empty == _iir ) {

        (chan->callbacks->xmt_char)(chan);

    } else if (( ISR_Rx_Avail == _iir ) || ( ISR_Rx_Char_Timeout == _iir )) {

        cyg_uint8 _c;

        HAL_READ_UINT8(port+SER_16550_RBR, _c);

        (chan->callbacks->rcv_char)(chan, _c);

    }

    cyg_drv_interrupt_unmask(atlas_chan->int_num);

}

#endif

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

// EOF atlas_serial.c