ser_16x5x.c

eCos操作系统源码

//==========================================================================
//
//      io/serial/generic/16x5x/ser_16x5x.c
//
//      Generic 16x5x serial driver
//
//==========================================================================
//####ECOSGPLCOPYRIGHTBEGIN####
// -------------------------------------------
// This file is part of eCos, the Embedded Configurable Operating System.
// Copyright (C) 1998, 1999, 2000, 2001, 2002 Red Hat, Inc.
// Copyright (C) 2003 Gary Thomas
//
// 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.
//
// 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.
//
// This exception does not invalidate any other reasons why a work based on
// 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):    gthomas
// Contributors: gthomas, jlarmour, jskov
// Date:         1999-02-04
// Purpose:      16x5x generic serial driver
// Description: 
//
//####DESCRIPTIONEND####
//
//==========================================================================

#include <pkgconf/system.h>
#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/io/serial.h>
#include <cyg/infra/diag.h>
#include <cyg/infra/cyg_ass.h>
#include <cyg/hal/hal_io.h>

// Only compile driver if an inline file with driver details was selected.
#ifdef CYGDAT_IO_SERIAL_GENERIC_16X5X_INL

#ifndef CYGPRI_IO_SERIAL_GENERIC_16X5X_STEP
#define CYGPRI_IO_SERIAL_GENERIC_16X5X_STEP 1
#endif

#define SER_REG(_x_) ((_x_)*CYGPRI_IO_SERIAL_GENERIC_16X5X_STEP)

// Receive control Registers
#define REG_rhr SER_REG(0)    // Receive holding register
#define REG_isr SER_REG(2)    // Interrupt status register
#define REG_lsr SER_REG(5)    // Line status register
#define REG_msr SER_REG(6)    // Modem status register
#define REG_scr SER_REG(7)    // Scratch register

// Transmit control Registers
#define REG_thr SER_REG(0)    // Transmit holding register
#define REG_ier SER_REG(1)    // Interrupt enable register
#define REG_fcr SER_REG(2)    // FIFO control register
#define REG_lcr SER_REG(3)    // Line control register
#define REG_mcr SER_REG(4)    // Modem control register
#define REG_ldl SER_REG(0)    // LSB of baud rate
#define REG_mdl SER_REG(1)    // MSB of baud rate

// Interrupt Enable Register
#define IER_RCV 0x01
#define IER_XMT 0x02
#define IER_LS  0x04
#define IER_MS  0x08

// Line Control Register
#define LCR_WL5 0x00    // Word length
#define LCR_WL6 0x01
#define LCR_WL7 0x02
#define LCR_WL8 0x03
#define LCR_SB1 0x00    // Number of stop bits
#define LCR_SB1_5 0x04  // 1.5 -> only valid with 5 bit words
#define LCR_SB2 0x04
#define LCR_PN  0x00    // Parity mode - none
#define LCR_PE  0x18    // Parity mode - even
#define LCR_PO  0x08    // Parity mode - odd
#define LCR_PM  0x28    // Forced "mark" parity
#define LCR_PS  0x38    // Forced "space" parity
#define LCR_DL  0x80    // Enable baud rate latch

// Line Status Register
#define LSR_RSR 0x01
#define LSR_OE  0x02
#define LSR_PE  0x04
#define LSR_FE  0x08
#define LSR_BI  0x10
#define LSR_THE 0x20
#define LSR_TEMT 0x40
#define LSR_FIE 0x80

// Modem Control Register
#define MCR_DTR  0x01
#define MCR_RTS  0x02
#define MCR_INT  0x08   // Enable interrupts
#define MCR_LOOP 0x10   // Loopback mode

// Interrupt status Register
#define ISR_MS        0x00
#define ISR_nIP       0x01
#define ISR_Tx        0x02
#define ISR_Rx        0x04
#define ISR_LS        0x06
#define ISR_RxTO      0x0C
#define ISR_64BFIFO   0x20
#define ISR_FIFOworks 0x40
#define ISR_FIFOen    0x80

// Modem Status Register
#define MSR_DCTS 0x01
#define MSR_DDSR 0x02
#define MSR_TERI 0x04
#define MSR_DDCD 0x08
#define MSR_CTS  0x10
#define MSR_DSR  0x20
#define MSR_RI   0x40
#define MSR_CD   0x80

// FIFO Control Register
#define FCR_FE   0x01    // FIFO enable
#define FCR_CRF  0x02    // Clear receive FIFO
#define FCR_CTF  0x04    // Clear transmit FIFO
#define FCR_DMA  0x08    // DMA mode select
#define FCR_F64  0x20    // Enable 64 byte fifo (16750+)
#define FCR_RT14 0xC0    // Set Rx trigger at 14
#define FCR_RT8  0x80    // Set Rx trigger at 8
#define FCR_RT4  0x40    // Set Rx trigger at 4
#define FCR_RT1  0x00    // Set Rx trigger at 1

static unsigned char select_word_length[] = {
    LCR_WL5,    // 5 bits / word (char)
    LCR_WL6,
    LCR_WL7,
    LCR_WL8
};

static unsigned char select_stop_bits[] = {
    0,
    LCR_SB1,    // 1 stop bit
    LCR_SB1_5,  // 1.5 stop bit
    LCR_SB2     // 2 stop bits
};

static unsigned char select_parity[] = {
    LCR_PN,     // No parity
    LCR_PE,     // Even parity
    LCR_PO,     // Odd parity
    LCR_PM,     // Mark parity
    LCR_PS,     // Space parity
};

// selec_baud[] must be define by the client

typedef struct pc_serial_info {
    cyg_addrword_t base;
    int            int_num;
    cyg_interrupt  serial_interrupt;
    cyg_handle_t   serial_interrupt_handle;
#ifdef CYGPKG_IO_SERIAL_GENERIC_16X5X_FIFO
    enum {
        sNone = 0,
        s8250,
        s16450,
        s16550,
        s16550a
    } deviceType;
#endif
} pc_serial_info;

static bool pc_serial_init(struct cyg_devtab_entry *tab);
static bool pc_serial_putc(serial_channel *chan, unsigned char c);
static Cyg_ErrNo pc_serial_lookup(struct cyg_devtab_entry **tab, 
                                  struct cyg_devtab_entry *sub_tab,
                                  const char *name);
static unsigned char pc_serial_getc(serial_channel *chan);
static Cyg_ErrNo pc_serial_set_config(serial_channel *chan, cyg_uint32 key,
                                      const void *xbuf, cyg_uint32 *len);
static void pc_serial_start_xmit(serial_channel *chan);
static void pc_serial_stop_xmit(serial_channel *chan);

static cyg_uint32 pc_serial_ISR(cyg_vector_t vector, cyg_addrword_t data);
static void       pc_serial_DSR(cyg_vector_t vector, cyg_ucount32 count,
                                cyg_addrword_t data);

static SERIAL_FUNS(pc_serial_funs, 
                   pc_serial_putc, 
                   pc_serial_getc,
                   pc_serial_set_config,
                   pc_serial_start_xmit,
                   pc_serial_stop_xmit
    );

#include CYGDAT_IO_SERIAL_GENERIC_16X5X_INL

#ifndef CYG_IO_SERIAL_GENERIC_16X5X_INT_PRIORITY
# define CYG_IO_SERIAL_GENERIC_16X5X_INT_PRIORITY 4
#endif


// Internal function to actually configure the hardware to desired
// baud rate, etc.
static bool
serial_config_port(serial_channel *chan, 
                   cyg_serial_info_t *new_config, bool init)
{
    pc_serial_info *ser_chan = (pc_serial_info *)chan->dev_priv;
    cyg_addrword_t base = ser_chan->base;
    unsigned short baud_divisor = select_baud[new_config->baud];
    unsigned char _lcr, _ier;
    if (baud_divisor == 0) return false;  // Invalid configuration

    // Disable port interrupts while changing hardware
    HAL_READ_UINT8(base+REG_ier, _ier);
    HAL_WRITE_UINT8(base+REG_ier, 0);

    _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(base+REG_lcr, _lcr | LCR_DL);
    HAL_WRITE_UINT8(base+REG_mdl, baud_divisor >> 8);
    HAL_WRITE_UINT8(base+REG_ldl, baud_divisor & 0xFF);
    HAL_WRITE_UINT8(base+REG_lcr, _lcr);
    if (init) {
#ifdef CYGPKG_IO_SERIAL_GENERIC_16X5X_FIFO
        unsigned char _fcr_thresh;
        cyg_uint8 b;

        /* First, find out what kind of device it is. */
        ser_chan->deviceType = sNone;
        HAL_WRITE_UINT8(base+REG_mcr, MCR_LOOP); // enable loopback mode
        HAL_READ_UINT8(base+REG_msr, b);         
        if (0 == (b & 0xF0)) {   // see if MSR had CD, RI, DSR or CTS set
            HAL_WRITE_UINT8(base+REG_mcr, MCR_LOOP|MCR_DTR|MCR_RTS);
            HAL_READ_UINT8(base+REG_msr, b);
            if (0xF0 != (b & 0xF0))  // check that all of CD,RI,DSR and CTS set
                ser_chan->deviceType = s8250;
        }
        HAL_WRITE_UINT8(base+REG_mcr, 0); // disable loopback mode

        if (ser_chan->deviceType == s8250) {
            // Check for a scratch register; scratch register 
            // indicates 16450 or above.
            HAL_WRITE_UINT8(base+REG_scr, 0x55);
            HAL_READ_UINT8(base+REG_scr, b);
            if (b == 0x55) {
                HAL_WRITE_UINT8(base+REG_scr, 0xAA);
                HAL_READ_UINT8(base+REG_scr, b);
                if (b == 0xAA)
                    ser_chan->deviceType = s16450;
            }
        }

        if (ser_chan->deviceType == s16450) {
            // Check for a FIFO
            HAL_WRITE_UINT8(base+REG_fcr, FCR_FE);
            HAL_READ_UINT8(base+REG_isr, b);
            if (b & ISR_FIFOen)
                ser_chan->deviceType = s16550; // but FIFO doesn't 
                                               // necessarily work
            if (b & ISR_FIFOworks)
                ser_chan->deviceType = s16550a; // 16550a FIFOs work
        }

        if (ser_chan->deviceType == s16550a) {
            switch(CYGPKG_IO_SERIAL_GENERIC_16X5X_FIFO_RX_THRESHOLD) {
            default:
            case 1:
                _fcr_thresh=FCR_RT1; break;
            case 4:
                _fcr_thresh=FCR_RT4; break;
            case 8:
                _fcr_thresh=FCR_RT8; break;
            case 14:
                _fcr_thresh=FCR_RT14; break;
            }
            _fcr_thresh|=FCR_FE|FCR_CRF|FCR_CTF;
            HAL_WRITE_UINT8(base+REG_fcr, _fcr_thresh); // Enable and clear FIFO
        }
        else
            HAL_WRITE_UINT8(base+REG_fcr, 0); // make sure it's disabled
#endif
        if (chan->out_cbuf.len != 0) {
            _ier = IER_RCV;
        } else {
            _ier = 0;
        }
        // Master interrupt enable
        HAL_WRITE_UINT8(base+REG_mcr, MCR_INT|MCR_DTR|MCR_RTS);
    }