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/** @file
Basic serial IO abstraction for GDB
Copyright (c) 2008 - 2009, Apple Inc. All rights reserved.<BR>
SPDX-License-Identifier: BSD-2-Clause-Patent
**/
#include <Uefi.h>
#include <Library/GdbSerialLib.h>
#include <Library/PcdLib.h>
#include <Library/IoLib.h>
#include <Library/DebugLib.h>
//---------------------------------------------
// UART Register Offsets
//---------------------------------------------
#define BAUD_LOW_OFFSET 0x00
#define BAUD_HIGH_OFFSET 0x01
#define IER_OFFSET 0x01
#define LCR_SHADOW_OFFSET 0x01
#define FCR_SHADOW_OFFSET 0x02
#define IR_CONTROL_OFFSET 0x02
#define FCR_OFFSET 0x02
#define EIR_OFFSET 0x02
#define BSR_OFFSET 0x03
#define LCR_OFFSET 0x03
#define MCR_OFFSET 0x04
#define LSR_OFFSET 0x05
#define MSR_OFFSET 0x06
//---------------------------------------------
// UART Register Bit Defines
//---------------------------------------------
#define LSR_TXRDY 0x20U
#define LSR_RXDA 0x01U
#define DLAB 0x01U
#define ENABLE_FIFO 0x01U
#define CLEAR_FIFOS 0x06U
// IO Port Base for the UART
UINTN gPort;
/**
The constructor function initializes the UART.
@param ImageHandle The firmware allocated handle for the EFI image.
@param SystemTable A pointer to the EFI System Table.
@retval EFI_SUCCESS The constructor always returns EFI_SUCCESS.
**/
RETURN_STATUS
EFIAPI
GdbSerialLibConstructor (
IN EFI_HANDLE ImageHandle,
IN EFI_SYSTEM_TABLE *SystemTable
)
{
UINT64 BaudRate;
UINT8 DataBits;
UINT8 Parity;
UINT8 StopBits;
gPort = (UINTN)PcdGet32 (PcdGdbUartPort);
BaudRate = PcdGet64 (PcdGdbBaudRate);
Parity = PcdGet8 (PcdGdbParity);
DataBits = PcdGet8 (PcdGdbDataBits);
StopBits = PcdGet8 (PcdGdbStopBits);
return GdbSerialInit (BaudRate, Parity, DataBits, StopBits);
}
/**
Sets the baud rate, receive FIFO depth, transmit/receive time out, parity,
data buts, and stop bits on a serial device. This call is optional as the serial
port will be set up with defaults base on PCD values.
@param BaudRate The requested baud rate. A BaudRate value of 0 will use the the
device's default interface speed.
@param Parity The type of parity to use on this serial device. A Parity value of
DefaultParity will use the device's default parity value.
@param DataBits The number of data bits to use on the serial device. A DataBits
value of 0 will use the device's default data bit setting.
@param StopBits The number of stop bits to use on this serial device. A StopBits
value of DefaultStopBits will use the device's default number of
stop bits.
@retval EFI_SUCCESS The device was configured.
@retval EFI_DEVICE_ERROR The serial device could not be configured.
**/
RETURN_STATUS
EFIAPI
GdbSerialInit (
IN UINT64 BaudRate,
IN UINT8 Parity,
IN UINT8 DataBits,
IN UINT8 StopBits
)
{
UINTN Divisor;
UINT8 OutputData;
UINT8 Data;
UINT8 BreakSet = 0;
//
// We assume the UART has been turned on to decode gPort address range
//
//
// Map 5..8 to 0..3
//
Data = (UINT8) (DataBits - (UINT8)5);
//
// Calculate divisor for baud generator
//
Divisor = 115200/(UINTN)BaudRate;
//
// Set communications format
//
OutputData = (UINT8)((DLAB << 7) | ((BreakSet << 6) | ((Parity << 3) | ((StopBits << 2) | Data))));
IoWrite8 (gPort + LCR_OFFSET, OutputData);
//
// Configure baud rate
//
IoWrite8 (gPort + BAUD_HIGH_OFFSET, (UINT8)(Divisor >> 8));
IoWrite8 (gPort + BAUD_LOW_OFFSET, (UINT8)(Divisor & 0xff));
//
// Switch back to bank 0
//
OutputData = (UINT8)((~DLAB<<7)|((BreakSet<<6)|((Parity<<3)|((StopBits<<2)| Data))));
IoWrite8 (gPort + LCR_OFFSET, OutputData);
// Not sure this is the right place to enable the FIFOs....
// We probably need the FIFO enabled to not drop input
IoWrite8 (gPort + FCR_SHADOW_OFFSET, ENABLE_FIFO);
// Configure the UART hardware here
return RETURN_SUCCESS;
}
/**
Check to see if a character is available from GDB. Do not read the character as that is
done via GdbGetChar().
@return TRUE - Character available
@return FALSE - Character not available
**/
BOOLEAN
EFIAPI
GdbIsCharAvailable (
VOID
)
{
UINT8 Data;
Data = IoRead8 (gPort + LSR_OFFSET);
return ((Data & LSR_RXDA) == LSR_RXDA);
}
/**
Get a character from GDB. This function must be able to run in interrupt context.
@return A character from GDB
**/
CHAR8
EFIAPI
GdbGetChar (
VOID
)
{
UINT8 Data;
CHAR8 Char;
// Wait for the serial port to be ready
do {
Data = IoRead8 (gPort + LSR_OFFSET);
} while ((Data & LSR_RXDA) == 0);
Char = IoRead8 (gPort);
// Make this an EFI_D_INFO after we get everything debugged.
DEBUG ((EFI_D_ERROR, "<%c<", Char));
return Char;
}
/**
Send a character to GDB. This function must be able to run in interrupt context.
@param Char Send a character to GDB
**/
VOID
EFIAPI
GdbPutChar (
IN CHAR8 Char
)
{
UINT8 Data;
// Make this an EFI_D_INFO after we get everything debugged.
DEBUG ((EFI_D_ERROR, ">%c>", Char));
// Wait for the serial port to be ready
do {
Data = IoRead8 (gPort + LSR_OFFSET);
} while ((Data & LSR_TXRDY) == 0);
IoWrite8 (gPort, Char);
}
/**
Send an ASCII string to GDB. This function must be able to run in interrupt context.
@param String Send a string to GDB
**/
VOID
GdbPutString (
IN CHAR8 *String
)
{
while (*String != '\0') {
GdbPutChar (*String);
String++;
}
}
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