reactos/boot/freeldr/freeldr/comm/rs232.c

   1 /*
   2  *  FreeLoader
   3  *  Copyright (C) 2001  Brian Palmer  <brianp@sginet.com>
   4  *  Copyright (C) 2001  Eric Kohl
   5  *  Copyright (C) 2001  Emanuele Aliberti
   6  *
   7  *  This program is free software; you can redistribute it and/or modify
   8  *  it under the terms of the GNU General Public License as published by
   9  *  the Free Software Foundation; either version 2 of the License, or
  10  *  (at your option) any later version.
  11  *
  12  *  This program is distributed in the hope that it will be useful,
  13  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  *  GNU General Public License for more details.
  16  *
  17  *  You should have received a copy of the GNU General Public License
  18  *  along with this program; if not, write to the Free Software
  19  *  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  20  */
  21
  22 #include <freeldr.h>
  23
  24 /* MACROS *******************************************************************/
  25
  26 #define DEFAULT_BAUD_RATE    19200
  27
  28 #define   SER_RBR(x)   ((x)+0)
  29 #define   SER_THR(x)   ((x)+0)
  30 #define   SER_DLL(x)   ((x)+0)
  31 #define   SER_IER(x)   ((x)+1)
  32 #define   SER_DLM(x)   ((x)+1)
  33 #define   SER_IIR(x)   ((x)+2)
  34 #define   SER_LCR(x)   ((x)+3)
  35 #define     SR_LCR_CS5 0x00
  36 #define     SR_LCR_CS6 0x01
  37 #define     SR_LCR_CS7 0x02
  38 #define     SR_LCR_CS8 0x03
  39 #define     SR_LCR_ST1 0x00
  40 #define     SR_LCR_ST2 0x04
  41 #define     SR_LCR_PNO 0x00
  42 #define     SR_LCR_POD 0x08
  43 #define     SR_LCR_PEV 0x18
  44 #define     SR_LCR_PMK 0x28
  45 #define     SR_LCR_PSP 0x38
  46 #define     SR_LCR_BRK 0x40
  47 #define     SR_LCR_DLAB 0x80
  48 #define   SER_MCR(x)   ((x)+4)
  49 #define     SR_MCR_DTR 0x01
  50 #define     SR_MCR_RTS 0x02
  51 #define   SER_LSR(x)   ((x)+5)
  52 #define     SR_LSR_DR  0x01
  53 #define     SR_LSR_TBE 0x20
  54 #define   SER_MSR(x)   ((x)+6)
  55 #define     SR_MSR_CTS 0x10
  56 #define     SR_MSR_DSR 0x20
  57 #define   SER_SCR(x)   ((x)+7)
  58
  59 /* STATIC VARIABLES *********************************************************/
  60
  61 static ULONG Rs232ComPort = 0;
  62 static ULONG Rs232BaudRate = 0;
  63 static PUCHAR Rs232PortBase = (PUCHAR)0;
  64
  65 /* The com port must only be initialized once! */
  66 static BOOLEAN PortInitialized = FALSE;
  67
  68 /* STATIC FUNCTIONS *********************************************************/
  69
  70 static BOOL Rs232DoesComPortExist(PUCHAR BaseAddress)
  71 {
  72         BOOLEAN found;
  73         UCHAR mcr;
  74         UCHAR msr;
  75
  76         found = FALSE;
  77
  78         /* save Modem Control Register (MCR) */
  79         mcr = READ_PORT_UCHAR (SER_MCR(BaseAddress));
  80
  81         /* enable loop mode (set Bit 4 of the MCR) */
  82         WRITE_PORT_UCHAR (SER_MCR(BaseAddress), 0x10);
  83
  84         /* clear all modem output bits */
  85         WRITE_PORT_UCHAR (SER_MCR(BaseAddress), 0x10);
  86
  87         /* read the Modem Status Register */
  88         msr = READ_PORT_UCHAR (SER_MSR(BaseAddress));
  89
  90         /*
  91          * the upper nibble of the MSR (modem output bits) must be
  92          * equal to the lower nibble of the MCR (modem input bits)
  93          */
  94         if ((msr & 0xF0) == 0x00)
  95         {
  96                 /* set all modem output bits */
  97                 WRITE_PORT_UCHAR (SER_MCR(BaseAddress), 0x1F);
  98
  99                 /* read the Modem Status Register */
 100                 msr = READ_PORT_UCHAR (SER_MSR(BaseAddress));
 101
 102                 /*
 103                  * the upper nibble of the MSR (modem output bits) must be
 104                  * equal to the lower nibble of the MCR (modem input bits)
 105                  */
 106                 if ((msr & 0xF0) == 0xF0)
 107                         found = TRUE;
 108         }
 109
 110         /* restore MCR */
 111         WRITE_PORT_UCHAR (SER_MCR(BaseAddress), mcr);
 112
 113         return (found);
 114 }
 115
 116 /* FUNCTIONS *********************************************************/
 117
 118 BOOL Rs232PortInitialize(ULONG ComPort, ULONG BaudRate)
 119 {
 120         ULONG BaseArray[5] = {0, 0x3F8, 0x2F8, 0x3E8, 0x2E8};
 121         //char buffer[80];
 122         ULONG divisor;
 123         UCHAR lcr;
 124
 125         if (PortInitialized == FALSE)
 126         {
 127                 if (BaudRate != 0)
 128                 {
 129                         Rs232BaudRate = BaudRate;
 130                 }
 131                 else
 132                 {
 133                         Rs232BaudRate = DEFAULT_BAUD_RATE;
 134                 }
 135
 136                 if (ComPort == 0)
 137                 {
 138                         if (Rs232DoesComPortExist ((PUCHAR)BaseArray[2]))
 139                         {
 140                                 Rs232PortBase = (PUCHAR)BaseArray[2];
 141                                 Rs232ComPort = 2;
 142 /*#ifndef NDEBUG
 143                                 sprintf (buffer,
 144                                          "\nSerial port COM%ld found at 0x%lx\n",
 145                                          ComPort,
 146                                          (ULONG)PortBase);
 147                                 HalDisplayString (buffer);
 148 #endif*/ /* NDEBUG */
 149                         }
 150                         else if (Rs232DoesComPortExist ((PUCHAR)BaseArray[1]))
 151                         {
 152                                 Rs232PortBase = (PUCHAR)BaseArray[1];
 153                                 Rs232ComPort = 1;
 154 /*#ifndef NDEBUG
 155                                 sprintf (buffer,
 156                                          "\nSerial port COM%ld found at 0x%lx\n",
 157                                          ComPort,
 158                                          (ULONG)PortBase);
 159                                 HalDisplayString (buffer);
 160 #endif*/ /* NDEBUG */
 161                         }
 162                         else
 163                         {
 164                                 /*sprintf (buffer,
 165                                          "\nKernel Debugger: No COM port found!!!\n\n");
 166                                 HalDisplayString (buffer);*/
 167                                 return FALSE;
 168                         }
 169                 }
 170                 else
 171                 {
 172                         if (Rs232DoesComPortExist ((PUCHAR)BaseArray[ComPort]))
 173                         {
 174                                 Rs232PortBase = (PUCHAR)BaseArray[ComPort];
 175                                 Rs232ComPort = ComPort;
 176 /*#ifndef NDEBUG
 177                                 sprintf (buffer,
 178                                          "\nSerial port COM%ld found at 0x%lx\n",
 179                                          ComPort,
 180                                          (ULONG)PortBase);
 181                                 HalDisplayString (buffer);
 182 #endif*/ /* NDEBUG */
 183                         }
 184                         else
 185                         {
 186                                 /*sprintf (buffer,
 187                                          "\nKernel Debugger: No serial port found!!!\n\n");
 188                                 HalDisplayString (buffer);*/
 189                                 return FALSE;
 190                         }
 191                 }
 192
 193                 PortInitialized = TRUE;
 194         }
 195
 196         /*
 197          * set baud rate and data format (8N1)
 198          */
 199
 200         /*  turn on DTR and RTS  */
 201         WRITE_PORT_UCHAR (SER_MCR(Rs232PortBase), SR_MCR_DTR | SR_MCR_RTS);
 202
 203         /* set DLAB */
 204         lcr = READ_PORT_UCHAR (SER_LCR(Rs232PortBase)) | SR_LCR_DLAB;
 205         WRITE_PORT_UCHAR (SER_LCR(Rs232PortBase), lcr);
 206
 207         /* set baud rate */
 208         divisor = 115200 / BaudRate;
 209         WRITE_PORT_UCHAR (SER_DLL(Rs232PortBase), divisor & 0xff);
 210         WRITE_PORT_UCHAR (SER_DLM(Rs232PortBase), (divisor >> 8) & 0xff);
 211
 212         /* reset DLAB and set 8N1 format */
 213         WRITE_PORT_UCHAR (SER_LCR(Rs232PortBase),
 214                           SR_LCR_CS8 | SR_LCR_ST1 | SR_LCR_PNO);
 215
 216         /* read junk out of the RBR */
 217         lcr = READ_PORT_UCHAR (SER_RBR(Rs232PortBase));
 218
 219         /*
 220          * set global info
 221          */
 222         //KdComPortInUse = (ULONG)PortBase;
 223
 224         /*
 225          * print message to blue screen
 226          */
 227         /*sprintf (buffer,
 228                  "\nKernel Debugger: COM%ld (Port 0x%lx) BaudRate %ld\n\n",
 229                  ComPort,
 230                  (ULONG)PortBase,
 231                  BaudRate);
 232
 233         HalDisplayString (buffer);*/
 234
 235         return TRUE;
 236 }
 237
 238 BOOL Rs232PortGetByte(PUCHAR ByteRecieved)
 239 {
 240         if (PortInitialized == FALSE)
 241                 return FALSE;
 242
 243         if ((READ_PORT_UCHAR (SER_LSR(Rs232PortBase)) & SR_LSR_DR))
 244         {
 245                 *ByteRecieved = READ_PORT_UCHAR (SER_RBR(Rs232PortBase));
 246                 return TRUE;
 247         }
 248
 249         return FALSE;
 250 }
 251
 252 BOOL Rs232PortPollByte(PUCHAR ByteRecieved)
 253 {
 254         if (PortInitialized == FALSE)
 255                 return FALSE;
 256
 257         while ((READ_PORT_UCHAR (SER_LSR(Rs232PortBase)) & SR_LSR_DR) == 0)
 258                 ;
 259
 260         *ByteRecieved = READ_PORT_UCHAR (SER_RBR(Rs232PortBase));
 261
 262         return TRUE;
 263 }
 264
 265 VOID Rs232PortPutByte(UCHAR ByteToSend)
 266 {
 267         if (PortInitialized == FALSE)
 268                 return;
 269
 270         while ((READ_PORT_UCHAR (SER_LSR(Rs232PortBase)) & SR_LSR_TBE) == 0)
 271                 ;
 272
 273         WRITE_PORT_UCHAR (SER_THR(Rs232PortBase), ByteToSend);
 274 }