private void _ReadBlock(ulong aBlockNo, byte[] aData, uint DataOffset)
{
// Setup the packet
#if PATAPI_TRACE
BasicConsole.WriteLine("Setup ATAPI packet");
#endif
byte[] atapi_packet = new byte[12];
atapi_packet[0] = 0xA8;
atapi_packet[1] = 0x0;
atapi_packet[2] = (byte)(aBlockNo >> 24);
atapi_packet[3] = (byte)(aBlockNo >> 16);
atapi_packet[4] = (byte)(aBlockNo >> 8);
atapi_packet[5] = (byte)(aBlockNo >> 0);
atapi_packet[6] = 0x0;
atapi_packet[7] = 0x0;
atapi_packet[8] = 0x0;
atapi_packet[9] = 1;
atapi_packet[10] = 0x0;
atapi_packet[11] = 0x0;
// Inform the controller we are using PIO mode
#if PATAPI_TRACE
BasicConsole.WriteLine("Tell controller we are using PIO mode");
#endif
BaseDevice.IO.Features.Write_Byte(0);
// Tell the drive the buffer size
#if PATAPI_TRACE
BasicConsole.WriteLine("Tell drive the buffer size");
#endif
BaseDevice.IO.LBA1.Write_Byte((byte)BlockSize); // Low byte
BaseDevice.IO.LBA1.Write_Byte((byte)(BlockSize >> 8)); // High byte
// Send the packet command (includes the wait)
#if PATAPI_TRACE
BasicConsole.WriteLine("Send Packet command");
#endif
PATABase.Status xStatus = BaseDevice.SendCmd(PATABase.Cmd.Packet);
// Error occurred
#if PATAPI_TRACE
BasicConsole.WriteLine("Check for error");
#endif
if ((xStatus & PATABase.Status.Error) != 0)
{
#if PATAPI_TRACE
BasicConsole.WriteLine("Error detected");
#endif
ExceptionMethods.Throw(new Exceptions.NoDiskException("ATAPI read error! Status bits incorrect in first check."));
}
// Check if that invoked an IRQ - it shouldn't have
#if PATAPI_TRACE
BasicConsole.WriteLine("Check if IRQ invoked");
#endif
if (IRQInvoked)
{
#if PATAPI_TRACE
BasicConsole.WriteLine("IRQ had been invoked");
#endif
// Allow future IRQs by reading Status register
BaseDevice.IO.Status.Read_Byte();
IRQInvoked = false;
}
// Send the data
#if PATAPI_TRACE
BasicConsole.WriteLine("Write packet data");
#endif
BaseDevice.IO.Data.Write_UInt16s(atapi_packet);
// Wait a bit
#if PATAPI_TRACE
BasicConsole.WriteLine("Brief wait");
#endif
BaseDevice.Wait();
// Wait for the IRQ
#if PATAPI_TRACE
BasicConsole.WriteLine("Wait for IRQ");
#endif
if (WaitForIRQ())
{
#if PATAPI_TRACE
BasicConsole.WriteLine("Error! Wait for IRQ timed out.");
BasicConsole.DelayOutput(5);
#endif
}
// Wait for Busy to clear and check alternate status
#if PATAPI_TRACE
BasicConsole.WriteLine("Wait till not busy");
#endif
uint timeout = 0xF0000000;
do
{
BaseDevice.Wait();
xStatus = (PATABase.Status)BaseDevice.IO.Control.Read_Byte();
} while ((xStatus & PATABase.Status.Busy) != 0 &&
(xStatus & PATABase.Status.Error) == 0 &&
timeout-- > 0);
// Read status reg to clear IRQ
#if PATAPI_TRACE
BasicConsole.WriteLine("Read status");
#endif
xStatus = (PATABase.Status)BaseDevice.IO.Status.Read_Byte();
IRQInvoked = false;
// Error occurred
#if PATAPI_TRACE
BasicConsole.WriteLine("Check for error");
#endif
if ((xStatus & (PATABase.Status.Error | PATABase.Status.ATA_SR_DF)) != 0 ||
(xStatus & PATABase.Status.DRQ) == 0)
{
#if PATAPI_TRACE
BasicConsole.WriteLine("Error detected");
#endif
ExceptionMethods.Throw(new Exceptions.NoDiskException("ATAPI read error! Status bits incorrect in second check."));
}
// Read the data
#if PATAPI_TRACE
BasicConsole.WriteLine("Read the data");
BasicConsole.WriteLine("Length: " + (FOS_System.String)aData.Length);
#endif
uint offset = DataOffset + 1;
uint i = 0;
for (; i < BlockSize && offset < aData.Length; i += 2, offset += 2)
{
UInt16 val = BaseDevice.IO.Data.Read_UInt16();
aData[offset - 1] = (byte)(val);
aData[offset] = (byte)(val >> 8);
}
// Clear out any remaining data
for (; i < BlockSize; i++)
{
BaseDevice.IO.Data.Read_UInt16();
}
#if PATAPI_TRACE
unsafe
{
BasicConsole.DumpMemory((byte *)Utilities.ObjectUtilities.GetHandle(aData) + FOS_System.Array.FieldsBytesSize, aData.Length);
}
BasicConsole.WriteLine("Wait for IRQ");
#endif
// Wait for IRQ
if (WaitForIRQ())
{
#if PATAPI_TRACE
BasicConsole.WriteLine("Error! Wait for IRQ timed out. (1)");
BasicConsole.DelayOutput(5);
#endif
}
// Wait for Busy and DRQ to clear and check status
#if PATAPI_TRACE
BasicConsole.WriteLine("Wait till not busy");
#endif
timeout = 0xF0000000;
do
{
BaseDevice.Wait();
xStatus = (PATABase.Status)BaseDevice.IO.Control.Read_Byte();
} while ((xStatus & (PATABase.Status.Busy | PATABase.Status.DRQ)) != 0 &&
(xStatus & PATABase.Status.Error) == 0 &&
timeout-- > 0);
// Error occurred
#if PATAPI_TRACE
BasicConsole.WriteLine("Check for error");
#endif
if ((xStatus & (PATABase.Status.Error | PATABase.Status.ATA_SR_DF)) != 0 ||
(xStatus & (PATABase.Status.DRQ)) != 0)
{
#if PATAPI_TRACE
BasicConsole.WriteLine("Error detected");
#endif
ExceptionMethods.Throw(new FOS_System.Exception("ATAPI read error! Status bits incorrect in third check."));
}
#if PATAPI_TRACE
BasicConsole.WriteLine("Complete");
BasicConsole.DelayOutput(10);
#endif
}
