/**
* We rely on our bootloader setting the A20, but we have code for it just in case.
*/
void SetupA20() {
uint8_t response_byte;
/* Do a couple of dummy writes to clear the output buffers. */
PS2ReadData();
PS2ReadData();
/* Disable interrupts. */
PICDisableInterrupts();
/* Disable both PS/2 ports. */
PS2WaitInputBuffer();
PS2SendCommand(PS2_COMMAND_DISABLE_PORT1);
PS2WaitInputBuffer();
PS2SendCommand(PS2_COMMAND_DISABLE_PORT2);
A20_check:
/* Tell the PS/2 controller to send us the config. */
PS2WaitInputBuffer();
PS2SendCommand(PS2_COMMAND_READ_CONFIG);
/* Get the status byte. */
response_byte = PS2ReadData();
/* Check if the A20 bit is set. */
if((response_byte & 0x02) != 0x02) {
/* A20 is NOT set. Set it and write it. */
PS2WaitOutputBuffer();
PS2SendCommand(PS2_COMMAND_WRITE_CONFIG);
PS2WaitOutputBuffer();
PS2SendData(response_byte | 0x02);
goto A20_check;
} else {
/* A20 was set. */
printf("PS/2 A20 line set.\n");
}
/* Re-enable both ports. */
PS2WaitInputBuffer();
PS2SendCommand(PS2_COMMAND_ENABLE_PORT1);
PS2WaitInputBuffer();
PS2SendCommand(PS2_COMMAND_ENABLE_PORT2);
/* And finally re-enable interrupts. */
PICResumeInterrupts();
return;
}
void SetupPS2() {
char response_byte;
/* Do a couple of dummy writes to clear the output buffers. */
PS2ReadData();
PS2ReadData();
/* Initialize USB controllers. */
/* Determine if PS2 exists using ACPI. */
/* Disable devices so they don't send data. */
PS2WaitInputBuffer();
PS2SendCommand(PS2_COMMAND_DISABLE_PORT1);
PS2WaitInputBuffer();
PS2SendCommand(PS2_COMMAND_DISABLE_PORT2);
/* Flush output buffer. */
PS2ReadStatus();
/* Set the controller configuration byte. */
response_byte = PS2ReadStatus();
/* Perform controller self test. */
PS2WaitInputBuffer();
PS2SendCommand(PS2_COMMAND_TEST_CONTROLLER);
PS2WaitOutputBuffer();
if(PS2ReadData() == PS2_RESPONSE_TEST_PASS) {
printf("PS/2 controller passed self test.\n");
} else {
printf("PS/2 controller did not pass self test.\n");
}
/* Determine if there is 2 channels. */
PS2WaitInputBuffer();
PS2SendCommand(PS2_COMMAND_ENABLE_PORT2);
PS2WaitInputBuffer();
PS2SendCommand(PS2_COMMAND_READ_CONFIG);
response_byte = PS2ReadData();
/* Check if bit 5 of the controller config is set. */
if(BIT_CHECK(response_byte, 5)) {
printf("PS/2 controller has no second channel.\n");
ps2_has_second_channel = false;
} else {
printf("PS/2 controller has a second channel.\n");
ps2_has_second_channel = true;
}
/* Disable port 2 again to finish startup. */
PS2WaitInputBuffer();
PS2SendCommand(PS2_COMMAND_DISABLE_PORT2);
/* Test port 1. */
PS2WaitInputBuffer();
PS2SendCommand(PS2_COMMAND_TEST_PORT1);
PS2WaitOutputBuffer();
response_byte = PS2ReadData();
switch(response_byte) {
case PS2_RESPONSE_PORT_TEST_PASS:
printf("PS/2 port 1 has passed self-test.\n");
break;
case PS2_RESPONSE_CLOCK_STUCK_LOW:
printf("PS/2 port 1 has stuck low clock.\n");
break;
case PS2_RESPONSE_CLOCK_STUCK_HIGH:
printf("PS/2 port 1 has stuck high clock.\n");
break;
case PS2_RESPONSE_DATA_STUCK_LOW:
printf("PS/2 port 1 has stuck low data line.\n");
break;
case PS2_RESPONSE_DATA_STUCK_HIGH:
printf("PS/2 port 1 has stuck high data line.\n");
break;
default:
printf("PS/2 port 1 has failed self-test.\n");
break;
}
/* Test port 2. */
PS2WaitInputBuffer();
PS2SendCommand(PS2_COMMAND_TEST_PORT2);
PS2WaitOutputBuffer();
response_byte = PS2ReadData();
switch(response_byte) {
case PS2_RESPONSE_PORT_TEST_PASS:
printf("PS/2 port 2 has passed self-test.\n");
break;
case PS2_RESPONSE_CLOCK_STUCK_LOW:
printf("PS/2 port 2 has stuck low clock.\n");
break;
case PS2_RESPONSE_CLOCK_STUCK_HIGH:
printf("PS/2 port 2 has stuck high clock.\n");
break;
case PS2_RESPONSE_DATA_STUCK_LOW:
printf("PS/2 port 2 has stuck low data line.\n");
break;
case PS2_RESPONSE_DATA_STUCK_HIGH:
printf("PS/2 port 2 has stuck high data line.\n");
break;
default:
printf("PS/2 port 2 has failed self-test.\n");
break;
}
/* Re-enable device 1. */
PS2WaitInputBuffer();
PS2SendCommand(PS2_COMMAND_ENABLE_PORT1);
/* Re-enable device 2. */
PS2WaitInputBuffer();
PS2SendCommand(PS2_COMMAND_ENABLE_PORT2);
/* Identify device 1. */
/* Identify device 2. */
}
static VOID WINAPI PS2WritePort(ULONG Port, BYTE Data)
{
if (Port == PS2_CONTROL_PORT)
{
switch (Data)
{
/* Read configuration byte */
case 0x20:
{
OutputBuffer = ControllerConfig;
StatusRegister |= (1 << 0); // There is something to read
break;
}
/* Write configuration byte */
case 0x60:
/* Write controller output port */
case 0xD1:
/* Write to the first PS/2 port output buffer */
case 0xD2:
/* Write to the second PS/2 port output buffer */
case 0xD3:
/* Write to the second PS/2 port input buffer */
case 0xD4:
{
/* These commands require a response */
ControllerCommand = Data;
StatusRegister |= (1 << 3); // This is a controller command
break;
}
/* Disable second PS/2 port */
case 0xA7:
{
Ports[1].IsEnabled = FALSE;
break;
}
/* Enable second PS/2 port */
case 0xA8:
{
Ports[1].IsEnabled = TRUE;
break;
}
/* Test second PS/2 port */
case 0xA9:
{
OutputBuffer = 0x00; // Success code
StatusRegister |= (1 << 0); // There is something to read
break;
}
/* Test PS/2 controller */
case 0xAA:
{
OutputBuffer = 0x55; // Success code
StatusRegister |= (1 << 0); // There is something to read
break;
}
/* Test first PS/2 port */
case 0xAB:
{
OutputBuffer = 0x00; // Success code
StatusRegister |= (1 << 0); // There is something to read
break;
}
/* Disable first PS/2 port */
case 0xAD:
{
Ports[0].IsEnabled = FALSE;
break;
}
/* Enable first PS/2 port */
case 0xAE:
{
Ports[0].IsEnabled = TRUE;
break;
}
/* Read controller output port */
case 0xD0:
{
// TODO: Not implemented
break;
}
/* CPU Reset */
case 0xF0:
case 0xF2:
case 0xF4:
case 0xF6:
case 0xF8:
case 0xFA:
case 0xFC:
case 0xFE:
{
/* Stop the VDM */
EmulatorTerminate();
break;
}
}
}
else if (Port == PS2_DATA_PORT)
{
/* Check if the controller is waiting for a response */
if (StatusRegister & (1 << 3)) // If we have data for the controller
{
StatusRegister &= ~(1 << 3);
/* Check which command it was */
switch (ControllerCommand)
{
/* Write configuration byte */
case 0x60:
{
ControllerConfig = Data;
break;
}
/* Write controller output */
case 0xD1:
{
/* Check if bit 0 is unset */
if (!(Data & (1 << 0)))
{
/* CPU disabled - Stop the VDM */
EmulatorTerminate();
}
/* Update the A20 line setting */
EmulatorSetA20(Data & (1 << 1));
break;
}
/* Push the data byte into the first PS/2 port queue */
case 0xD2:
{
PS2QueuePush(0, Data);
break;
}
/* Push the data byte into the second PS/2 port queue */
case 0xD3:
{
PS2QueuePush(1, Data);
break;
}
/*
* Send a command to the second PS/2 port (by default
* it is a command for the first PS/2 port)
*/
case 0xD4:
{
PS2SendCommand(&Ports[1], Data);
break;
}
}
return;
}
/* By default, send a command to the first PS/2 port */
PS2SendCommand(&Ports[0], Data);
}
}