apps/window_server/SerialMouse.cpp

   1 #include <i386/io.h>
   2 #include <blt/syscall.h>
   3 #include <stdio.h>
   4 #include "SerialMouse.h"
   5 #include "util.h"
   6
   7 #define POLL 1
   8
   9 const int kBaudRate = 1200;
  10 const int kPortBase = 0x3f8;
  11
  12 SerialMouse::SerialMouse(int xmax, int ymax)
  13         :       fXPos(xmax / 2),
  14                 fYPos(ymax / 2),
  15                 fXMax(xmax),
  16                 fYMax(ymax)
  17 {
  18         unsigned short divisor = 115200 / kBaudRate;
  19
  20         outb(0, kPortBase + 1);                                 // No interrupts for now
  21         outb(0, kPortBase + 4);                                 // clear DTR and RTS
  22
  23         outb(0x80, kPortBase + 3);                              // load divisor latch
  24         outb((divisor & 0xff), kPortBase);              // divisor LSB
  25         outb((divisor >> 8), kPortBase + 1);    // divisor MSB
  26         outb(2, kPortBase + 3);                                 // clear DLAB, set up for 7N1
  27
  28         outb(3, kPortBase + 4);                                 // Say hello.  Raise DTR and RTS
  29         if (SerialRead() == 'M')
  30                 printf("Detected MS serial mouse\n");
  31 }
  32
  33
  34 // The data is sent in 3 byte packets in following format:
  35 //         D7      D6      D5      D4      D3      D2      D1      D0
  36 // 1.      X       1       LB      RB      Y7      Y6      X7      X6
  37 // 2.      X       0       X5      X4      X3      X2      X1      X0
  38 // 3.      X       0       Y5      Y4      Y3      Y2      Y1      Y0
  39 void SerialMouse::GetPos(int *out_x, int *out_y, int *out_buttons)
  40 {
  41         char b1;
  42
  43         // loop until we get to the beginning of a packet
  44         while (true) {
  45                 b1 = SerialRead();
  46                 if ((b1 & (1 << 6)) != 0)
  47                         break;          // beginning of packet
  48         }
  49
  50         char b2 = SerialRead();
  51         char b3 = SerialRead();
  52
  53         fXPos += (int)(char)((b1 << 6) | (b2 & 0x3f));
  54         fYPos += (int)(char)(((b1 << 4) & 0xc0) | (b3 & 0x3f));
  55
  56         fXPos = min(fXPos, fXMax);
  57         fXPos = max(fXPos, 0);
  58         fYPos = min(fYPos, fYMax);
  59         fYPos = max(fYPos, 0);
  60
  61         *out_buttons = (b1 >> 4) & 3;
  62         *out_x = fXPos;
  63         *out_y = fYPos;
  64 }
  65
  66 unsigned char SerialMouse::SerialRead()
  67 {
  68         while (true) {
  69 #if POLL
  70                 while ((inb(kPortBase + 5) & 1) == 0)
  71                         ;
  72 #else
  73                 os_handle_irq(4);
  74                 outb(1, kPortBase + 1);         // Interrupt on recieve ready
  75                 os_sleep_irq();
  76                 int id = inb(kPortBase + 2);
  77                 if ((id & 1) == 0 || (id >> 1) != 2)
  78                         continue;                               // Not for me
  79 #endif
  80
  81                 break;
  82         }
  83
  84         return inb(kPortBase);
  85 }
  86