uartio.c File Reference

#include "common.h"

Macros
#define	MAX_REGISTER_WIDTH   32

Functions
BOOLEAN	UartpSetAccess (_Inout_ PCPPORT Port, const BOOLEAN MemoryMapped, const UCHAR AccessSize, const UCHAR BitWidth)

Macro Definition Documentation

MAX_REGISTER_WIDTH

#define MAX_REGISTER_WIDTH   32

Function Documentation

UartpSetAccess()

BOOLEAN UartpSetAccess	(	_Inout_ PCPPORT	Port,
		const BOOLEAN	MemoryMapped,
		const UCHAR	AccessSize,
		const UCHAR	BitWidth )

{
    UCHAR                             MinRegisterWidth;
    BOOLEAN                           PowerOfTwo;
    UART_HARDWARE_READ_INDEXED_UCHAR  ReadFunction;
    UART_HARDWARE_WRITE_INDEXED_UCHAR WriteFunction;
 
    MinRegisterWidth = 8;
 
    //
    // Select the appropriate port access routines depending upon whether this
    // serial port is mapped into memory or I/O space.
    //
 
    if (MemoryMapped == FALSE)
    {
        switch ((ACPI_GENERIC_ACCESS_SIZE)AccessSize)
        {
#if defined(_X86_) || defined(_AMD64_)
 
        case AcpiGenericAccessSizeLegacy:
            __fallthrough;
 
        case AcpiGenericAccessSizeByte:
            WriteFunction = WritePortWithIndex8;
            ReadFunction  = ReadPortWithIndex8;
            break;
 
        case AcpiGenericAccessSizeWord:
            WriteFunction    = WritePortWithIndex16;
            ReadFunction     = ReadPortWithIndex16;
            MinRegisterWidth = 16;
            break;
 
        case AcpiGenericAccessSizeDWord:
            WriteFunction    = WritePortWithIndex32;
            ReadFunction     = ReadPortWithIndex32;
            MinRegisterWidth = 32;
            break;
 
            //
            // The quad word access size isn't supported for port based I/O.
            //
 
#endif
 
        default:
            return FALSE;
        }
    }
    else
    {
        switch ((ACPI_GENERIC_ACCESS_SIZE)AccessSize)
        {
        case AcpiGenericAccessSizeLegacy:
            __fallthrough;
 
        case AcpiGenericAccessSizeByte:
            WriteFunction = WriteRegisterWithIndex8;
            ReadFunction  = ReadRegisterWithIndex8;
            break;
 
        case AcpiGenericAccessSizeWord:
            WriteFunction    = WriteRegisterWithIndex16;
            ReadFunction     = ReadRegisterWithIndex16;
            MinRegisterWidth = 16;
            break;
 
        case AcpiGenericAccessSizeDWord:
            WriteFunction    = WriteRegisterWithIndex32;
            ReadFunction     = ReadRegisterWithIndex32;
            MinRegisterWidth = 32;
            break;
 
#if defined(_WIN64)
 
        case AcpiGenericAccessSizeQWord:
            WriteFunction    = WriteRegisterWithIndex64;
            ReadFunction     = ReadRegisterWithIndex64;
            MinRegisterWidth = 64;
            break;
 
#endif
 
        default:
            return FALSE;
        }
    }
 
    //
    // Validate BitWidth parameter.
    //
 
    PowerOfTwo = ((BitWidth & (BitWidth - 1)) == 0);
    if ((PowerOfTwo == FALSE) ||
        (BitWidth < MinRegisterWidth) ||
        (BitWidth > MAX_REGISTER_WIDTH))
    {
        return FALSE;
    }
 
    Port->ByteWidth = BitWidth / 8;
    Port->Write     = WriteFunction;
    Port->Read      = ReadFunction;
    return TRUE;
}