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/*

 * Project: S.Ha.R.K.

 *

 * Coordinators:

 *   Giorgio Buttazzo    <giorgio@sssup.it>

 *   Paolo Gai           <pj@gandalf.sssup.it>

 *

 * Authors     :

 *   Paolo Gai           <pj@gandalf.sssup.it>

 *   Massimiliano Giorgi <massy@gandalf.sssup.it>

 *   Luca Abeni          <luca@gandalf.sssup.it>

 *   (see the web pages for full authors list)

 *

 * ReTiS Lab (Scuola Superiore S.Anna - Pisa - Italy)

 *

 * http://www.sssup.it

 * http://retis.sssup.it

 * http://shark.sssup.it

 */

/**

 ------------

 CVS :        $Id: scom.c,v 1.1 2004-03-29 18:31:42 mauro Exp $

 File:        $File$

 Revision:    $Revision: 1.1 $

 Last update: $Date: 2004-03-29 18:31:42 $

 ------------

 Author:      Massimiliano Giorgi

 Author:        Gerardo Lamastra

 Date:  9/5/96

 File:  SCOM.C

 Revision:      1.0g

**/

/*

 * Copyright (C) 2000 Paolo Gai

 *

 * 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

 *

 */

/* Serial communication device */

/* This implementation is capable of handling 4 distinct COM ports */

/* The COM port settings are the standard PC settings:             */

/* PORT         ADDRESS         IRQ                                */

/*   1           0x3F8           4                                 */

/*   2           0x2F8           3                                 */

/*   3           0x3E8           4                                 */

/*   4           0x2E8           2                                 */

/* By Massy

 * I have modified the fast handler routines to support serial

 * mouse better (see below)

 */

//#include <string.h>

//#include <stdlib.h>

//#include <cons.h>

#include <kernel/kern.h>

//#include "exc.h"

#include <modules/sem.h>

#include <drivers/scom.h>

/* #define __DEBUG_SERIAL__ */

/* #define __STUB__ */

/* Base address for each standard COM link */

static unsigned com_base[] = {0x03F8,0x02F8,0x03E8,0x02E8};

/* Irq linked to each serial channel */

static unsigned com_irq[]  = {COM1_IRQ,COM2_IRQ,COM3_IRQ,COM4_IRQ};

/* COM port which shares interrupt with indexed one             */

/* I assume standard AT assignement where each irq line can     */

/* hold up to 2 different COM port                              */

static const int com_share[] = {COM3,COM4,COM1,COM2};

/* Used for decoding the IIR status */

const int IIRbits[] = {MS_CHANGED,TX_EMPTY,RX_FULL,LS_CHANGED};

/* The descriptor of a serial link                               */

/* Each array entry is associated to a COM port                  */

/* The control field is used to specify which kind of interrupts */

/* are going to be served; the status field tracks if the entry  */

/* is curretly used & if the shared fast handler is linked       */

/* The semaphores are opened if you use an asyncronous server    */

/* with the link                                                 */

struct COM_LINK com_link[COM_LINKS];

/* Register level access functions */

unsigned com_read(unsigned port,unsigned reg)

{

    unsigned b;

    if (port > 3 || reg > 7) return(0);

    b = ll_in(com_base[port]+reg);

    return(b);

}

void com_write(unsigned port,unsigned reg,unsigned value)

{

    if (port > 3 || reg > 7) return;

    ll_out(com_base[port]+reg,value);

}

/* Polled send/receive */

void com_send(unsigned port,BYTE b)

{

    while ((com_read(port,LSR) & 32) == 0);

    com_write(port,THR,b);

}

unsigned com_receive(unsigned port)

{

    while ((com_read(port,LSR) & 1) == 0);

    return(com_read(port,RBR));

}

/* Fast routines for cascaded irq */

/* By massy */

/* com_fast must be called if there isn't a server

 * and an interrupt is detected (so sermouse.c module can

 * activate mouse task only if a packet not a byte is received).

 */

static void dummy(int x) {}

void (*com_fast)(int)=dummy;

#ifdef __DEBUG_SERIAL__

    int fast_times1 = 0,fast_times3 = 0;

#endif

static void com_1_3_fast(int n)

{

  unsigned iir1,iir3;

  iir1 = DECODE(com_read(COM1,IIR));

  iir3 = DECODE(com_read(COM3,IIR));

  if ((iir1 & com_link[COM1].control)) {

#ifdef __DEBUG_SERIAL__

    fast_times1++;

#endif

    com_write(COM1,IER,0);

    com_link[COM1].request = iir1;

    if (com_link[COM1].server==NIL)

      com_fast(COM1);

    else

      task_activate(com_link[COM1].server);

  }

  else if ((iir3 & com_link[COM3].control)) {

#ifdef __DEBUG_SERIAL__

    fast_times3++;

#endif

    com_write(COM3,IER,0);

    com_link[COM3].request = iir3;

    if (com_link[COM3].server==NIL)

      com_fast(COM3);

    else

    task_activate(com_link[COM3].server);

  }

}

#ifdef __DEBUG_SERIAL__

    int fast_times2 = 0,fast_times4 = 0;

#endif

static void com_2_4_fast(int n)

{

  unsigned iir2,iir4;

  iir2 = DECODE(com_read(COM2,IIR));

  iir4 = DECODE(com_read(COM4,IIR));

  if ((iir2 & com_link[COM2].control)) {

#ifdef __DEBUG_SERIAL__

    fast_times2++;

#endif

    com_write(COM2,IER,0);

    com_link[COM2].request = iir2;

    if (com_link[COM2].server==NIL)

      com_fast(COM2);

    else    

      task_activate(com_link[COM2].server);

  }

  else if ((iir4 & com_link[COM4].control)) {

#ifdef __DEBUG_SERIAL__

    fast_times4++;

#endif

    com_write(COM4,IER,0);

    com_link[COM4].request = iir4;

    if (com_link[COM4].server==NIL)

      com_fast(COM4);

    else    

      task_activate(com_link[COM4].server);

  }

}

/* Initialize a serial channel */

int com_open(unsigned port,DWORD speed,BYTE parity,BYTE len,BYTE stop)

{

    unsigned long div,b_mask;

    /* Check if link is already open */

    cli();

    if (com_link[port].status & LINK_BUSY) {

        sti();

        return(-1);

    } else com_link[port].status |= LINK_BUSY;

    sti();

    /* Now set up the serial link */

    b_mask = (parity & 3) * 8 + (stop & 1) * 4 + ((len - 5) & 3);

    div = 115200L / speed;

    /* Clear serial interrupt enable register */

    com_write(port,IER,0);

    /* Empty input buffer */

    com_read(port,RBR);

    /* Activate DLAB bit for speed setting */

    com_write(port,LCR,0x80);

    /* Load baud divisor */

    com_write(port,0,div & 0x00FF);

    div >>= 8;

    com_write(port,1,div & 0x00FF);

    /* Load control word (parity,stop bit,bit len) */

    com_write(port,LCR,b_mask);

    /* Attiva OUT1 & OUT2 */

    com_write(port,MCR,0x0C);

    return(1);

}

/* Link a particular server to a serial channel                 */

/* The semaphores are opened to syncronize the server and the   */

/* application task which use serial communication              */

int com_server(unsigned port,unsigned control,PID server)

{

    unsigned hndl = com_irq[port];

    unsigned shared = com_share[port];

    void (*com_fast)(int n);

    /* Select appropriate fast routine */

    if (port == COM1 || port == COM3) com_fast = com_1_3_fast;

    else if (port == COM2 || port == COM4) com_fast = com_2_4_fast;

    else return(-1);

    if ((control & (RX_FULL|TX_EMPTY)) == 0) return(-1);

    /* If the fast routine is not already installed, install it! */

    cli();

    if (!(com_link[port].status & FAST_INSTALLED)) {

        bit_on(com_link[port].status,FAST_INSTALLED);

        bit_on(com_link[shared].status,FAST_INSTALLED);

        handler_set(hndl,com_fast,NIL, TRUE);

        #ifdef __DEBUG_SERIAL__

            cputs("Handler OK\n");

        #endif

    }

    sti();

    /* Set com link tasks & flags */

    com_link[port].control = control;

    com_link[port].server = server;

    com_link[port].msk = 0;

    if (control & RX_FULL) sem_init(&com_link[port].rx_sem,0,0);

    if (control & TX_EMPTY) sem_init(&com_link[port].tx_sem,0,0);

    sem_init(&com_link[port].mutex,0,1);

    return(1);

}

/* Close port channel & release the server */

int com_close(unsigned port)

{    

    unsigned hndl = com_irq[port];

    unsigned shared = com_share[port];

    /* Check if fast is already installed */

    cli();

    if (!(com_link[port].status & LINK_BUSY)) {

        sti();

        return(-1);

    } else {

        if (com_link[port].control & RX_FULL) sem_destroy(&com_link[port].rx_sem);

        if (com_link[port].control & TX_EMPTY) sem_destroy(&com_link[port].tx_sem);

        com_write(port,IER,0);

        com_read(port,IIR);

        com_read(port,RBR);

        com_link[port].status = 0;

        com_link[port].control = 0;

        com_link[port].msk = 0;

        sti();

        sem_destroy(&com_link[port].mutex);

        if (com_link[port].server != NIL) {

            task_kill(com_link[port].server);

            com_link[port].server = NIL;

        }

    }

    /* If the fast routine is no more necessary, remove it */

    if (!(com_link[shared].status & FAST_INSTALLED))

       handler_remove(hndl);

    /* If the other link still uses it, we must remember this */

    else com_link[port].status = FAST_INSTALLED;

    return(1);

}

#ifdef __DEBUG_SERIAL__

    int rx_time = 0;

    int tx_time = 0;

#endif

/* This is the full duplex server; used for bidirectional data  */

/* transmission.                                                */

/* As intr is masked, the server can only be activated once     */

/* and operates in mutex with the fast handler                  */

/* This server operates in conjunction with the com_Async...    */

/* procedures!                                                  */

TASK duplexServer(int port)

{

    char data;

    for(;;) {

        if (com_link[port].request & RX_FULL) {

            #ifdef __DEBUG_SERIAL__

                putc_xy(78,0,RED,'R');

                rx_time++;

            #endif

            data = com_read(port,RBR);

            *(com_link[port].rx_buf + com_link[port].rx_cnt) = data;

            com_link[port].rx_cnt++;

            if (com_link[port].rx_cnt == com_link[port].rx_len) {

               bit_off(com_link[port].msk,RX_FULL);

               sem_post(&com_link[port].rx_sem);

            }

        }

        if (com_link[port].request & TX_EMPTY) {

            #ifdef __DEBUG_SERIAL__

                putc_xy(79,0,GREEN,'T');

                tx_time++;

            #endif

            data = *(com_link[port].tx_buf + com_link[port].tx_cnt);

            com_link[port].tx_cnt++;

            com_write(port,THR,data);

            if (com_link[port].tx_cnt == com_link[port].tx_len) {

               bit_off(com_link[port].msk,TX_EMPTY);

               sem_post(&com_link[port].tx_sem);

            }

        }

        cli();

        com_write(port,IER,com_link[port].msk);

        task_endcycle();

        sti();

    }

}

/* This routines provides asyncronous decoupling between the server */

/* and the tasks which produce/consume serial data                  */

void com_AsyncSend(int port,void *buf,unsigned len)

{

    sem_wait(&com_link[port].mutex);

    com_link[port].tx_buf = buf;

    com_link[port].tx_cnt = 0;

    com_link[port].tx_len = len;

    bit_on(com_link[port].msk,TX_EMPTY);

    sem_post(&com_link[port].mutex);

    com_write(port,IER,com_link[port].msk);

    sem_wait(&com_link[port].tx_sem);

}

void com_AsyncReceive(int port,void *buf,unsigned len)

{    

    sem_wait(&com_link[port].mutex);

    com_link[port].rx_buf = buf;

    com_link[port].rx_cnt = 0;

    com_link[port].rx_len = len;    

    bit_on(com_link[port].msk,RX_FULL);

    sem_post(&com_link[port].mutex);

    com_write(port,IER,com_link[port].msk);

    sem_wait(&com_link[port].rx_sem);

}

/* Receive Only Server                                          */

/* This server is used for passive devices which cannot receive */

/* data, but only transmit. I assume that only one byte is pro- */

/* cessed each time and the byte is got to the control process  */

TASK rxServer(int port)

{

    static char data;

    com_link[port].rx_buf = &data;

    for(;;) {

        #ifdef __DEBUG_SERIAL__

            putc_xy(76,0,YELLOW,'R');

        #endif

        data = com_read(port,RBR);

        sem_post(&com_link[port].rx_sem);

        cli();

        com_write(port,IER,com_link[port].msk);

        task_endcycle();

        sti();

    }

}

/* Debug Stub */

#ifdef __STUB__

#include "keyb.h"

TASK Visualize(void)

{

    char str[40];

    char buf[80];

    unsigned long times = 0;

    for (;;) {

        com_AsyncReceive(COM2,str,10);

        sprintf(buf,"Str : %s (Times : %lu)",str,times++);

        puts_xy(0,1,WHITE,buf);

    }

}

TASK Sender(void)

{

    char buf[80];

    unsigned long times = 0;

    cputs("Sender has started...\n");

    for (;;) {

        buf[0] = keyb_getchar();

        if (buf[0] == 'x') task_activate(MAIN_INDEX);

        if ((times % 10) == 9) buf[0] = 0;

        com_AsyncSend(COM2,buf,1);

        sprintf(buf,"Sender (Times : %lu)",times++);

        puts_xy(0,3,WHITE,buf);

    }

}        0

void main()

{

    PID p1,p2,p3;

    BYTE m1 = TX_EMPTY|RX_FULL;

    BYTE m2 = RX_FULL;

    BYTE m3 = TX_EMPTY;

    MODEL m = BASE_MODEL;

    MODEL mm = BASE_MODEL;

    sys_init(1000,uSec,0);

    keyb_init(HARD,50);

    clear();

    /* This is the sequence of operations needed to setup */

    /* a serial asyncronous bidirectional link            */

    task_def_arg(m,COM2);

    task_def_wcet(m,500);

    p1 = task_create("ComDuplex",duplexServer,HARD,APERIODIC,100,&m);

    if (p1 == -1) {

        ll_printf("Error creating comduplex task\n");

        sys_end();

        exit(-1);

    }

    com_open(COM2,9600,NONE,8,1);

    com_server(COM2,m1,p1);

    /* Well, that is some other stuff ... */

    task_def_wcet(mm,500);

    p2 = task_create("Visor",Visualize,NRT,APERIODIC,11,&mm);

    p3 = task_create("Sender",Sender,NRT,APERIODIC,11,&mm);

    task_activate(p2);

    task_activate(p3);

    task_endcycle();

    sys_end();

    #ifdef __DEBUG_SERIAL__

        cprintf("RxServer was activated %d times\n",rx_time);

        cprintf("TxServer was activated %d times\n",tx_time);

        cprintf("Fast : %d\n",fast_times1);

    #endif

}

#endif