/**
* PROJECT: ExectOS
* COPYRIGHT: See COPYING.md in the top level directory
* FILE: sdk/xtklib/hl/cport.c
* DESCRIPTION: Serial (COM) port support
* DEVELOPERS: Rafal Kupiec <belliash@codingworkshop.eu.org>
*/
#include "xtkmapi.h"
#include "xtklib.h"
/* I/O port addresses for COM1 - COM8 (valid only for ia32 and amd64) */
ULONG ComPortAddress[] = {0x000, 0x3F8, 0x2F8, 0x3E8, 0x2E8, 0x5F8, 0x4F8, 0x5E8, 0x4E8};
/**
* This routine gets a byte from serial port.
*
* @param Port
* Address of port object describing a port settings.
*
* @param Byte
* Address of variable where to store the result.
*
* @param Wait
* Specifies whether to wait for a data or not.
*
* @param Poll
* Indicates whether to only poll, not reading the data.
*
* @return This routine returns a status code.
*
* @since XT 1.0
*/
XTSTATUS
HlComPortGetByte(IN PCPPORT Port,
OUT PUCHAR Byte,
IN BOOLEAN Wait,
IN BOOLEAN Poll)
{
UCHAR Lsr;
ULONG Retry;
/* Make sure the port has been initialized */
if(Port->Address == 0)
{
return STATUS_DEVICE_NOT_READY;
}
/* Retry getting data if allowed to wait */
Retry = Wait ? COMPORT_WAIT_TIMEOUT : 1;
while(Retry--)
{
/* Get LSR for data ready */
Lsr = HlComPortReadLsr(Port, COMPORT_LSR_DR);
if((Lsr & COMPORT_LSR_DR) == COMPORT_LSR_DR)
{
/* Check for errors */
if(Lsr & (COMPORT_LSR_FE | COMPORT_LSR_OE | COMPORT_LSR_PE))
{
/* Framing, parity or overrun error occurred */
*Byte = 0;
return STATUS_IO_DEVICE_ERROR;
}
/* Check if only polling */
if(Poll)
{
/* Only polling, return success */
return STATUS_SUCCESS;
}
/* Read the byte from serial port */
*Byte = HlIoPortInByte(PtrToUshort(Port->Address + (ULONG)COMPORT_REG_RBR));
/* Check if in modem control mode */
if(Port->Flags & COMPORT_FLAG_MC)
{
/* Handle Carrier Detected (CD) */
if((HlIoPortInByte(PtrToShort(Port->Address + (ULONG)COMPORT_REG_MSR)) & COMPORT_MSR_DCD) == 0)
{
/* Skip byte if no CD present */
continue;
}
}
return STATUS_SUCCESS;
}
}
/* Reset LSR and return that no data found */
HlComPortReadLsr(Port, 0);
return STATUS_NOT_FOUND;
}
/**
* Reads LSR from specified serial port.
*
* @param Port
* Address of COM port.
*
* @param Byte
* Value expected from the port.
*
* @return Byte read from COM port.
*
* @since XT 1.0
*/
UCHAR
HlComPortReadLsr(IN PCPPORT Port,
IN UCHAR Byte)
{
UCHAR Lsr, Msr;
STATIC UCHAR RingFlag;
/* Read the Line Status Register (LSR) */
Lsr = HlIoPortInByte(PtrToUshort(Port->Address + (ULONG)COMPORT_REG_LSR));
/* Check if expected byte is present */
if((Lsr & Byte) == 0)
{
/* Check Modem Status Register (MSR) for ring indicator */
Msr = HlIoPortInByte(PtrToUshort(Port->Address + (ULONG)COMPORT_REG_MSR));
RingFlag |= (Msr & COMPORT_MSR_RI) ? 1 : 2;
if(RingFlag == 3)
{
/* Ring indicator toggled, use modem control */
Port->Flags |= COMPORT_FLAG_MC;
}
}
/* Return byte read */
return Lsr;
}
/**
* This routine writes a byte to the serial port.
*
* @param Port
* Address of port object describing a port settings.
*
* @param Byte
* Data to be written.
*
* @return This routine returns a status code.
*
* @since XT 1.0
*/
XTSTATUS
HlComPortPutByte(IN PCPPORT Port,
IN UCHAR Byte)
{
UCHAR Lsr, Msr;
/* Make sure the port has been initialized */
if(Port->Address == 0)
{
return STATUS_DEVICE_NOT_READY;
}
/* Check if port is in modem control */
while(Port->Flags & COMPORT_FLAG_MC)
{
/* Get the Modem Status Register (MSR) */
Msr = HlIoPortInByte(PtrToUshort(Port->Address + (ULONG)COMPORT_REG_MSR)) & COMPORT_MSR_DSRCTSCD;
if(Msr != COMPORT_MSR_DSRCTSCD)
{
/* Take character, if CD is not set */
Lsr = HlComPortReadLsr(Port, 0);
if((Msr & COMPORT_MSR_DCD) == 0 && (Lsr & COMPORT_LSR_DR) == COMPORT_LSR_DR)
{
/* Eat the character */
HlIoPortInByte(PtrToUshort(Port->Address + (ULONG)COMPORT_REG_RBR));
}
}
else
{
/* CD, CTS and DSR are set, we can continue */
break;
}
}
/* Wait for busy port */
while((HlComPortReadLsr(Port, COMPORT_LSR_THRE) & COMPORT_LSR_THRE) == 0);
/* Send byte to the port */
HlIoPortOutByte(PtrToUshort(Port->Address + (ULONG)COMPORT_REG_THR), Byte);
return STATUS_SUCCESS;
}
/**
* This routine initializes the COM port.
*
* @param Port
* Address of port object describing a port settings.
*
* @param PortNumber
* Supplies a port number.
*
* @param BaudRate
* Supplies an optional port baud rate.
*
* @return This routine returns a status code.
*
* @since XT 1.0
*/
XTSTATUS
HlInitializeComPort(IN OUT PCPPORT Port,
IN ULONG PortNumber,
IN ULONG BaudRate)
{
PUCHAR Address;
UCHAR Byte = 0;
USHORT Flags = 0;
ULONG Mode;
/* Check if serial port is set */
if(PortNumber == 0)
{
/* Use COM1 by default */
PortNumber = 1;
}
/* We support only a pre-defined number of ports */
if(PortNumber > ARRAY_SIZE(ComPortAddress))
{
/* Fail if wrong/unsupported port used */
return STATUS_INVALID_PARAMETER;
}
/* Check if baud rate is set */
if(BaudRate == 0)
{
/* Use default baud (clock) rate if not set */
BaudRate = COMPORT_CLOCK_RATE;
Flags |= COMPORT_FLAG_DBR;
}
/* Store COM pointer */
Address = UlongToPtr(ComPortAddress[PortNumber]);
/* Check whether this port is not already initialized */
if((Port->Address == Address) && (Port->Baud == BaudRate))
{
return STATUS_SUCCESS;
}
/* Test if chosen COM port exists */
do
{
/* Check whether the 16450/16550 scratch register exists */
HlIoPortOutByte(PtrToUshort(Address + (ULONG)COMPROT_REG_SR), Byte);
if(HlIoPortInByte(PtrToUshort(Address + (ULONG)COMPROT_REG_SR)) != Byte)
{
return STATUS_NOT_FOUND;
}
} while(++Byte != 0);
/* Disable interrupts */
HlIoPortOutByte(PtrToUshort(Address + (ULONG)COMPORT_REG_LCR), COMPORT_LSR_DIS);
HlIoPortOutByte(PtrToUshort(Address + (ULONG)COMPORT_REG_IER), COMPORT_LSR_DIS);
/* Enable Divisor Latch Access Bit (DLAB) */
HlIoPortOutByte(PtrToUshort(Address + (ULONG)COMPORT_REG_LCR), COMPORT_LCR_DLAB);
/* Set baud rate */
Mode = COMPORT_CLOCK_RATE / BaudRate;
HlIoPortOutByte(PtrToUshort(Address + (ULONG)COMPORT_DIV_DLL), (UCHAR)(Mode & 0xFF));
HlIoPortOutByte(PtrToUshort(Address + (ULONG)COMPORT_DIV_DLM), (UCHAR)((Mode >> 8) & 0xFF));
/* Set 8 data bits, 1 stop bits, no parity (8n1) */
HlIoPortOutByte(PtrToUshort(Address + (ULONG)COMPORT_REG_LCR),
COMPORT_LCR_8DATA | COMPORT_LCR_1STOP | COMPORT_LCR_PARN);
/* Enable DTR, RTS and OUT2 */
HlIoPortOutByte(PtrToUshort(Address + (ULONG)COMPORT_REG_MCR),
COMPORT_MCR_DTR | COMPORT_MCR_RTS | COMPORT_MCR_OUT2);
/* Enable FIFO */
HlIoPortOutByte(PtrToUshort(Address + (ULONG)COMPORT_REG_FCR),
COMPORT_FCR_ENABLE | COMPORT_FCR_RCVR_RESET | COMPORT_FCR_TXMT_RESET);
/* Enable loopback mode and test serial port */
HlIoPortOutByte(PtrToUshort(Address + (ULONG)COMPORT_REG_MCR), COMPORT_MCR_LOOP);
HlIoPortOutByte(PtrToUshort(Address + (ULONG)COMPORT_REG_RBR), COMPORT_MSR_TST);
if(HlIoPortInByte(PtrToUshort(Address + (ULONG)COMPORT_REG_RBR)) != COMPORT_MSR_TST)
{
return STATUS_IO_DEVICE_ERROR;
}
/* Mark port as fully initialized */
Flags |= COMPORT_FLAG_INIT;
/* Disable loopback mode and use port normally */
HlIoPortOutByte(PtrToUshort(Address + (ULONG)COMPORT_REG_MCR), COMPORT_MCR_NOM);
Port->Address = Address;
Port->Baud = BaudRate;
Port->Flags = Flags;
/* Return success */
return STATUS_SUCCESS;
}