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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 DEBUG_INFO after we get everything debugged.
- DEBUG ((DEBUG_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 DEBUG_INFO after we get everything debugged.
- DEBUG ((DEBUG_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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