slimbootloader/BootloaderCommonPkg/Library/ShellLib/CmdMem.c

/** @file
  Shell command `mem` to read/write system memory.

  Copyright (c) 2017, Intel Corporation. All rights reserved.<BR>
  SPDX-License-Identifier: BSD-2-Clause-Patent

**/

#include <Library/ShellLib.h>

/**
  Read or write system memory.

  @param[in]  Shell        shell instance
  @param[in]  Argc         number of command line arguments
  @param[in]  Argv         command line arguments

  @retval EFI_SUCCESS

**/
STATIC
EFI_STATUS
ShellCommandMemFunc (
  IN SHELL  *Shell,
  IN UINTN   Argc,
  IN CHAR16 *Argv[]
  );

CONST SHELL_COMMAND ShellCommandMem = {
  L"mem",
  L"Read or write system memory",
  &ShellCommandMemFunc
};

/**
  Read or write system memory.

  @param[in]  Shell        shell instance
  @param[in]  Argc         number of command line arguments
  @param[in]  Argv         command line arguments

  @retval EFI_SUCCESS

**/
STATIC
EFI_STATUS
ShellCommandMemFunc (
  IN SHELL  *Shell,
  IN UINTN   Argc,
  IN CHAR16 *Argv[]
  )
{
  UINTN   Index, Start, ItemsPerRow, Addr, Count, Width;
  BOOLEAN Write;
  UINT64  Value;

  Width = 4;
  Write = FALSE;
  Value = 0;

  if ((Argc == 2) || (Argc == 3)) {
    // Read 1 element
    Count = 1;
  } else if (Argc == 4) {
    // Read multiple elements
    Count = StrHexToUintn (Argv[3]);
  } else if ((Argc == 5) && (StrCmp (Argv[3], L"=") == 0)) {
    // Write 1 element
    Write = TRUE;
    Value = StrHexToUint64 (Argv[4]);
  } else {
    // Invalid
    goto usage;
  }

  // Parse access width
  if (Argc > 2) {
    Width = StrHexToUintn (Argv[2]);
    if ((Width != 1) && (Width != 2) && (Width != 4) && (Width != 8)) {
      ShellPrint (L"Error: Width must be 1, 2, 4, or 8\n");
      return EFI_INVALID_PARAMETER;
    }
  }

  // Parse access address
  Addr = StrHexToUintn (Argv[1]);

  // Make sure access is aligned
  if ((Addr & (Width - 1)) != 0) {
    ShellPrint (L"Error: Unaligned access\n");
    return EFI_INVALID_PARAMETER;
  }

  if (Write) {
    switch (Width) {
    case 1:
      * (volatile UINT8 *)Addr = (UINT8 )Value;
      break;
    case 2:
      * (volatile UINT16 *)Addr = (UINT16)Value;
      break;
    case 4:
      * (volatile UINT32 *)Addr = (UINT32)Value;
      break;
    case 8:
      * (volatile UINT64 *)Addr = (UINT64)Value;
      break;
    default:
      break;
    }
  } else {
    // Pad backward to 16-byte boundary
    ItemsPerRow  = 16 / Width;
    Start        = (Addr & 0xf) / Width;
    Count       += Start;

    if (Start > 0) {
      ShellPrint (L"%08x: ", Addr & ~0xf);
      for (Index = 0; Index < Start * (Width * 2 + 1); Index++) {
        ShellPrint (L" ");
      }
    }

    for (Index = Start; Index < Count; Index++) {
      if ((Index % ItemsPerRow) == 0) {
        ShellPrint (L"%08x: ", Addr);
      }

      switch (Width) {
      case 1:
        ShellPrint (L"%02x ",    * (volatile UINT8 *)Addr);
        break;
      case 2:
        ShellPrint (L"%04x ",    * (volatile UINT16 *)Addr);
        break;
      case 4:
        ShellPrint (L"%08x ",    * (volatile UINT32 *)Addr);
        break;
      case 8:
        ShellPrint (L"%016llx ", * (volatile UINT64 *)Addr);
        break;
      default:
        break;
      }

      if ((Index % ItemsPerRow) == (ItemsPerRow - 1)) {
        ShellPrint (L"\n");
      }

      Addr += Width;
    }

    if ((Index % ItemsPerRow) != 0) {
      ShellPrint (L"\n");
    }
  }

  return EFI_SUCCESS;

usage:
  ShellPrint (L"Usage: %s <addr> [<width> [<count> | = <val>]]\n", Argv[0]);
  return EFI_ABORTED;
}