/*
 * Copyright (C) 2013 Jerry Hoemann <jerry.hoemann@hp.com>
 *
 * Application to allocate memory at EFI.  Syntax of command
 * mimics the EFI Boot Service "FreePages."
 *
 * See UEFI spec 2.3, Section 6.2.
 *

Example freeing a 5 page BS_Code setment at address: 0000000020000000 (hex)


FS1:\> memmap
Type      Start            End              #pages             Attributes
BS_Code   0000000000000000-0000000000000FFF 0000000000000001 000000000000000F
Available 0000000000001000-000000000008DFFF 000000000000008D 000000000000000F
Reserved  000000000008E000-000000000008FFFF 0000000000000002 000000000000000F
Available 0000000000090000-000000000009FFFF 0000000000000010 000000000000000F
Available 0000000000100000-000000000FFFFFFF 000000000000FF00 000000000000000F
BS_Code   0000000010000000-0000000010061FFF 0000000000000062 000000000000000F
Available 0000000010062000-000000001FFFFFFF 000000000000FF9E 000000000000000F
BS_Code   0000000020000000-0000000020004FFF 0000000000000005 000000000000000F
Available 0000000020005000-000000005DDFFFFF 000000000003DDFB 000000000000000F
BS_Data   000000005DE00000-000000005DFFFFFF 0000000000000200 000000000000000F
Available 000000005E000000-000000006DE7CFFF 000000000000FE7D 000000000000000F
ACPI_NVS  000000006DE7D000-000000006EE7CFFF 0000000000001000 000000000000000F
BS_Data   000000006EE7D000-00000000709FBFFF 0000000000001B7F 000000000000000F
Available 00000000709FC000-00000000710E3FFF 00000000000006E8 000000000000000F


FS1:\> FreePages 0000000020000000 5
FreePages: __PhysAddr__ __PgCnt__
__PhysAddr__   0... 3FFFFFFFFFFF
__PgCnt__     [0..F000000]
All numbers hex w/ no leading 0x

FreePages(20000000,5)



FS1:\> memmap
Type      Start            End              #pages             Attributes
BS_Code   0000000000000000-0000000000000FFF 0000000000000001 000000000000000F
Available 0000000000001000-000000000008DFFF 000000000000008D 000000000000000F
Reserved  000000000008E000-000000000008FFFF 0000000000000002 000000000000000F
Available 0000000000090000-000000000009FFFF 0000000000000010 000000000000000F
Available 0000000000100000-000000000FFFFFFF 000000000000FF00 000000000000000F
BS_Code   0000000010000000-0000000010061FFF 0000000000000062 000000000000000F
Available 0000000010062000-000000005DDFFFFF 000000000004DD9E 000000000000000F
BS_Data   000000005DE00000-000000005DFFFFFF 0000000000000200 000000000000000F
Available 000000005E000000-000000006DE7CFFF 000000000000FE7D 000000000000000F
ACPI_NVS  000000006DE7D000-000000006EE7CFFF 0000000000001000 000000000000000F
BS_Data   000000006EE7D000-00000000709FBFFF 0000000000001B7F 000000000000000F
Available 00000000709FC000-00000000710E3FFF 00000000000006E8 000000000000000F


 */

#include <efi.h>
#include <efilib.h>

/*
 * FreePages:  __PhysAddr__ __PgCnt__
 *
 */

#define MAX_NUM_PAGES 0x000000000F000000

#define MAX_ADDR ((1ULL << 46) - 1)

#define	MAX_ARGS 256

#define CHAR_SPACE L' '

#define DEBUG 0

INTN
argify(CHAR16 *buf, UINTN len, CHAR16 **argv)   
{

        UINTN     i=0, j=0;
        CHAR16   *p = buf;
	
        if (buf == 0) { 
		argv[0] = NULL;
		return 0;
	}
	/* len represents the number of bytes, not the number of 16 bytes chars */
	len = len >> 1;

	/*
	 * Here we use CHAR_NULL as the terminator rather than the length
	 * because it seems like the EFI shell return rather bogus values for it.
	 * Apparently, we are guaranteed to find the '\0' character in the buffer
	 * where the real input arguments stop, so we use it instead.
	 */
	for(;;) {
		while (buf[i] == CHAR_SPACE && buf[i] != CHAR_NULL && i < len) i++;

		if (buf[i] == CHAR_NULL || i == len) goto end;

		p = buf+i;
		i++;

		while (buf[i] != CHAR_SPACE && buf[i] != CHAR_NULL && i < len) i++;

		argv[j++] = p;

		if (buf[i] == CHAR_NULL) goto end;

		buf[i]  = CHAR_NULL;

		if (i == len)  goto end;

		i++;

		if (j == MAX_ARGS-1) {
			Print(L"too many arguments (%d) truncating\n", j);
			goto end;
		}
	}
end:
        argv[j] = NULL;
	return j;
}


EFI_STATUS
efi_main (EFI_HANDLE image, EFI_SYSTEM_TABLE *systab)
{

	EFI_STATUS efi_status;
	EFI_GUID LoadedImageProtocol = LOADED_IMAGE_PROTOCOL;
	EFI_LOADED_IMAGE *info;

	CHAR16 arglist[MAX_ARGS+1] = {0};
	CHAR16 *argv[MAX_ARGS];
	INTN argc = 0;
	INTN err = 0;

	INTN PgCnt = -1;
	UINTN PhysAddr = 0;

	InitializeLib(image, systab);

        efi_status = uefi_call_wrapper( BS->HandleProtocol, 3, image,
                &LoadedImageProtocol, &info);


	Print(L"FreePages: __PhysAddr__ __PgCnt__\n");
	Print(L"__PhysAddr__   0... %llx\n", MAX_ADDR);
	Print(L"__PgCnt__     [0..%lx]\n", MAX_NUM_PAGES);
	Print(L"All numbers hex w/ no leading 0x\n");
	Print(L"\n");

#if DEBUG
	Print(L"%s\n", info->LoadOptions);
#endif


#if DEBUG
	Print(L"Set up arglist\n");
#endif
	CopyMem(arglist, info->LoadOptions, info->LoadOptionsSize);
#if DEBUG
	Print(L"arglist = <%s>\n", arglist);
#endif
	
#if DEBUG
	Print(L"Now try argify\n");
#endif
	argc = argify(arglist, info->LoadOptionsSize, argv);
#if DEBUG
	Print(L"argc = %d\n", argc);
#endif

#if DEBUG
	for (c = 0;  c < argc;  c++ ) {
		Print(L"argv[%d] = <%s>\n", c, argv[c]);
	}
#endif
	if (argc != 3) {
		Print(L"Invalid argument count\n");
		return EFI_SUCCESS;
	}

	PhysAddr = xtoi(argv[1]);
	PgCnt	 = xtoi(argv[2]);

	if ( (PgCnt < 0) || (PgCnt > MAX_NUM_PAGES) ) {
		Print(L"Inavlid PgCnt\n");
		err++;
	}
	if ( PhysAddr > MAX_ADDR ) {
		Print(L"Inavlid Address\n");
		err++;
	}
	if ( err ) {
		return EFI_SUCCESS;
	}

	Print(L"FreePages(%lx,%d)\n", PhysAddr, PgCnt);

	efi_status = uefi_call_wrapper(BS->FreePages, 2, PhysAddr, PgCnt);

	if ( EFI_ERROR(efi_status) ) {
		Print(L"Free Pages Failed: %d\n", efi_status);
		return efi_status;
	}

	return EFI_SUCCESS;
}