[mirror_edk2.git] / OvmfPkg / Library / QemuFwCfgLib / QemuFwCfgLib.c

/** @file\r
\r
  Copyright (c) 2011 - 2013, Intel Corporation. All rights reserved.<BR>\r
  Copyright (C) 2013, Red Hat, Inc.\r
  Copyright (c) 2017, AMD Incorporated. All rights reserved.<BR>\r
\r
  This program and the accompanying materials\r
  are licensed and made available under the terms and conditions of the BSD License\r
  which accompanies this distribution.  The full text of the license may be found at\r
  http://opensource.org/licenses/bsd-license.php\r
\r
  THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,\r
  WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.\r
\r
**/\r
\r
#include "Uefi.h"\r
#include <Library/BaseLib.h>\r
#include <Library/BaseMemoryLib.h>\r
#include <Library/DebugLib.h>\r
#include <Library/IoLib.h>\r
#include <Library/QemuFwCfgLib.h>\r
#include <Library/MemoryAllocationLib.h>\r
#include <Library/UefiBootServicesTableLib.h>\r
\r
#include "QemuFwCfgLibInternal.h"\r
\r
\r
/**\r
  Selects a firmware configuration item for reading.\r
  \r
  Following this call, any data read from this item will start from\r
  the beginning of the configuration item's data.\r
\r
  @param[in] QemuFwCfgItem - Firmware Configuration item to read\r
\r
**/\r
VOID\r
EFIAPI\r
QemuFwCfgSelectItem (\r
  IN FIRMWARE_CONFIG_ITEM   QemuFwCfgItem\r
  )\r
{\r
  DEBUG ((EFI_D_INFO, "Select Item: 0x%x\n", (UINT16)(UINTN) QemuFwCfgItem));\r
  IoWrite16 (0x510, (UINT16)(UINTN) QemuFwCfgItem);\r
}\r
\r
\r
/**\r
  Transfer an array of bytes, or skip a number of bytes, using the DMA\r
  interface.\r
\r
  @param[in]     Size     Size in bytes to transfer or skip.\r
\r
  @param[in,out] Buffer   Buffer to read data into or write data from. Ignored,\r
                          and may be NULL, if Size is zero, or Control is\r
                          FW_CFG_DMA_CTL_SKIP.\r
\r
  @param[in]     Control  One of the following:\r
                          FW_CFG_DMA_CTL_WRITE - write to fw_cfg from Buffer.\r
                          FW_CFG_DMA_CTL_READ  - read from fw_cfg into Buffer.\r
                          FW_CFG_DMA_CTL_SKIP  - skip bytes in fw_cfg.\r
**/\r
VOID\r
InternalQemuFwCfgDmaBytes (\r
  IN     UINT32   Size,\r
  IN OUT VOID     *Buffer OPTIONAL,\r
  IN     UINT32   Control\r
  )\r
{\r
  volatile FW_CFG_DMA_ACCESS Access;\r
  UINT32                     AccessHigh, AccessLow;\r
  UINT32                     Status;\r
\r
  ASSERT (Control == FW_CFG_DMA_CTL_WRITE || Control == FW_CFG_DMA_CTL_READ ||\r
    Control == FW_CFG_DMA_CTL_SKIP);\r
\r
  if (Size == 0) {\r
    return;\r
  }\r
\r
  Access.Control = SwapBytes32 (Control);\r
  Access.Length  = SwapBytes32 (Size);\r
  Access.Address = SwapBytes64 ((UINTN)Buffer);\r
\r
  //\r
  // Delimit the transfer from (a) modifications to Access, (b) in case of a\r
  // write, from writes to Buffer by the caller.\r
  //\r
  MemoryFence ();\r
\r
  //\r
  // Start the transfer.\r
  //\r
  AccessHigh = (UINT32)RShiftU64 ((UINTN)&Access, 32);\r
  AccessLow  = (UINT32)(UINTN)&Access;\r
  IoWrite32 (0x514, SwapBytes32 (AccessHigh));\r
  IoWrite32 (0x518, SwapBytes32 (AccessLow));\r
\r
  //\r
  // Don't look at Access.Control before starting the transfer.\r
  //\r
  MemoryFence ();\r
\r
  //\r
  // Wait for the transfer to complete.\r
  //\r
  do {\r
    Status = SwapBytes32 (Access.Control);\r
    ASSERT ((Status & FW_CFG_DMA_CTL_ERROR) == 0);\r
  } while (Status != 0);\r
\r
  //\r
  // After a read, the caller will want to use Buffer.\r
  //\r
  MemoryFence ();\r
}\r
\r
\r
/**\r
  Reads firmware configuration bytes into a buffer\r
\r
  @param[in] Size - Size in bytes to read\r
  @param[in] Buffer - Buffer to store data into  (OPTIONAL if Size is 0)\r
\r
**/\r
VOID\r
EFIAPI\r
InternalQemuFwCfgReadBytes (\r
  IN UINTN                  Size,\r
  IN VOID                   *Buffer  OPTIONAL\r
  )\r
{\r
  if (InternalQemuFwCfgDmaIsAvailable () && Size <= MAX_UINT32) {\r
    InternalQemuFwCfgDmaBytes ((UINT32)Size, Buffer, FW_CFG_DMA_CTL_READ);\r
    return;\r
  }\r
  IoReadFifo8 (0x511, Size, Buffer);\r
}\r
\r
\r
/**\r
  Reads firmware configuration bytes into a buffer\r
\r
  If called multiple times, then the data read will\r
  continue at the offset of the firmware configuration\r
  item where the previous read ended.\r
\r
  @param[in] Size - Size in bytes to read\r
  @param[in] Buffer - Buffer to store data into\r
\r
**/\r
VOID\r
EFIAPI\r
QemuFwCfgReadBytes (\r
  IN UINTN                  Size,\r
  IN VOID                   *Buffer\r
  )\r
{\r
  if (InternalQemuFwCfgIsAvailable ()) {\r
    InternalQemuFwCfgReadBytes (Size, Buffer);\r
  } else {\r
    ZeroMem (Buffer, Size);\r
  }\r
}\r
\r
/**\r
  Write firmware configuration bytes from a buffer\r
\r
  If called multiple times, then the data written will\r
  continue at the offset of the firmware configuration\r
  item where the previous write ended.\r
\r
  @param[in] Size - Size in bytes to write\r
  @param[in] Buffer - Buffer to read data from\r
\r
**/\r
VOID\r
EFIAPI\r
QemuFwCfgWriteBytes (\r
  IN UINTN                  Size,\r
  IN VOID                   *Buffer\r
  )\r
{\r
  if (InternalQemuFwCfgIsAvailable ()) {\r
    if (InternalQemuFwCfgDmaIsAvailable () && Size <= MAX_UINT32) {\r
      InternalQemuFwCfgDmaBytes ((UINT32)Size, Buffer, FW_CFG_DMA_CTL_WRITE);\r
      return;\r
    }\r
    IoWriteFifo8 (0x511, Size, Buffer);\r
  }\r
}\r
\r
\r
/**\r
  Reads a UINT8 firmware configuration value\r
\r
  @return    Value of Firmware Configuration item read\r
\r
**/\r
UINT8\r
EFIAPI\r
QemuFwCfgRead8 (\r
  VOID\r
  )\r
{\r
  UINT8 Result;\r
\r
  QemuFwCfgReadBytes (sizeof (Result), &Result);\r
\r
  return Result;\r
}\r
\r
\r
/**\r
  Reads a UINT16 firmware configuration value\r
\r
  @return    Value of Firmware Configuration item read\r
\r
**/\r
UINT16\r
EFIAPI\r
QemuFwCfgRead16 (\r
  VOID\r
  )\r
{\r
  UINT16 Result;\r
\r
  QemuFwCfgReadBytes (sizeof (Result), &Result);\r
\r
  return Result;\r
}\r
\r
\r
/**\r
  Reads a UINT32 firmware configuration value\r
\r
  @return    Value of Firmware Configuration item read\r
\r
**/\r
UINT32\r
EFIAPI\r
QemuFwCfgRead32 (\r
  VOID\r
  )\r
{\r
  UINT32 Result;\r
\r
  QemuFwCfgReadBytes (sizeof (Result), &Result);\r
\r
  return Result;\r
}\r
\r
\r
/**\r
  Reads a UINT64 firmware configuration value\r
\r
  @return    Value of Firmware Configuration item read\r
\r
**/\r
UINT64\r
EFIAPI\r
QemuFwCfgRead64 (\r
  VOID\r
  )\r
{\r
  UINT64 Result;\r
\r
  QemuFwCfgReadBytes (sizeof (Result), &Result);\r
\r
  return Result;\r
}\r
\r
\r
/**\r
  Find the configuration item corresponding to the firmware configuration file.\r
\r
  @param[in]  Name - Name of file to look up.\r
  @param[out] Item - Configuration item corresponding to the file, to be passed\r
                     to QemuFwCfgSelectItem ().\r
  @param[out] Size - Number of bytes in the file.\r
\r
  @return    RETURN_SUCCESS       If file is found.\r
             RETURN_NOT_FOUND     If file is not found.\r
             RETURN_UNSUPPORTED   If firmware configuration is unavailable.\r
\r
**/\r
RETURN_STATUS\r
EFIAPI\r
QemuFwCfgFindFile (\r
  IN   CONST CHAR8           *Name,\r
  OUT  FIRMWARE_CONFIG_ITEM  *Item,\r
  OUT  UINTN                 *Size\r
  )\r
{\r
  UINT32 Count;\r
  UINT32 Idx;\r
\r
  if (!InternalQemuFwCfgIsAvailable ()) {\r
    return RETURN_UNSUPPORTED;\r
  }\r
\r
  QemuFwCfgSelectItem (QemuFwCfgItemFileDir);\r
  Count = SwapBytes32 (QemuFwCfgRead32 ());\r
\r
  for (Idx = 0; Idx < Count; ++Idx) {\r
    UINT32 FileSize;\r
    UINT16 FileSelect;\r
    UINT16 FileReserved;\r
    CHAR8  FName[QEMU_FW_CFG_FNAME_SIZE];\r
\r
    FileSize     = QemuFwCfgRead32 ();\r
    FileSelect   = QemuFwCfgRead16 ();\r
    FileReserved = QemuFwCfgRead16 ();\r
    (VOID) FileReserved; /* Force a do-nothing reference. */\r
    InternalQemuFwCfgReadBytes (sizeof (FName), FName);\r
\r
    if (AsciiStrCmp (Name, FName) == 0) {\r
      *Item = SwapBytes16 (FileSelect);\r
      *Size = SwapBytes32 (FileSize);\r
      return RETURN_SUCCESS;\r
    }\r
  }\r
\r
  return RETURN_NOT_FOUND;\r
}\r
\r
\r
/**\r
  Determine if S3 support is explicitly enabled.\r
\r
  @retval  TRUE   if S3 support is explicitly enabled.\r
           FALSE  otherwise. This includes unavailability of the firmware\r
                  configuration interface.\r
**/\r
BOOLEAN\r
EFIAPI\r
QemuFwCfgS3Enabled (\r
  VOID\r
  )\r
{\r
  RETURN_STATUS        Status;\r
  FIRMWARE_CONFIG_ITEM FwCfgItem;\r
  UINTN                FwCfgSize;\r
  UINT8                SystemStates[6];\r
\r
  Status = QemuFwCfgFindFile ("etc/system-states", &FwCfgItem, &FwCfgSize);\r
  if (Status != RETURN_SUCCESS || FwCfgSize != sizeof SystemStates) {\r
    return FALSE;\r
  }\r
  QemuFwCfgSelectItem (FwCfgItem);\r
  QemuFwCfgReadBytes (sizeof SystemStates, SystemStates);\r
  return (BOOLEAN) (SystemStates[3] & BIT7);\r
}\r
Commit	Line	Data
f1ec65ba	1	/** @file\r
f1ec65ba	2	\r
29874a8c	3	Copyright (c) 2011 - 2013, Intel Corporation. All rights reserved.<BR>\r
0dc231c9	4	Copyright (C) 2013, Red Hat, Inc.\r
2b631390	5	Copyright (c) 2017, AMD Incorporated. All rights reserved.<BR>\r
f1ec65ba	6	\r
	7	This program and the accompanying materials\r
	8	are licensed and made available under the terms and conditions of the BSD License\r
	9	which accompanies this distribution. The full text of the license may be found at\r
	10	http://opensource.org/licenses/bsd-license.php\r
	11	\r
	12	THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,\r
	13	WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.\r
	14	\r
	15	**/\r
	16	\r
	17	#include "Uefi.h"\r
	18	#include <Library/BaseLib.h>\r
	19	#include <Library/BaseMemoryLib.h>\r
	20	#include <Library/DebugLib.h>\r
	21	#include <Library/IoLib.h>\r
	22	#include <Library/QemuFwCfgLib.h>\r
	23	#include <Library/MemoryAllocationLib.h>\r
	24	#include <Library/UefiBootServicesTableLib.h>\r
	25	\r
5297c0bf LE	26	#include "QemuFwCfgLibInternal.h"\r
5297c0bf LE	27	\r
f1ec65ba	28	\r
f1ec65ba	29	/**\r
	30	Selects a firmware configuration item for reading.\r
	31	\r
	32	Following this call, any data read from this item will start from\r
	33	the beginning of the configuration item's data.\r
	34	\r
	35	@param[in] QemuFwCfgItem - Firmware Configuration item to read\r
	36	\r
	37	**/\r
	38	VOID\r
	39	EFIAPI\r
	40	QemuFwCfgSelectItem (\r
	41	IN FIRMWARE_CONFIG_ITEM QemuFwCfgItem\r
	42	)\r
	43	{\r
	44	DEBUG ((EFI_D_INFO, "Select Item: 0x%x\n", (UINT16)(UINTN) QemuFwCfgItem));\r
	45	IoWrite16 (0x510, (UINT16)(UINTN) QemuFwCfgItem);\r
	46	}\r
	47	\r
	48	\r
2c8dcbc6	49	/**\r
d055601e LE	50	Transfer an array of bytes, or skip a number of bytes, using the DMA\r
d055601e LE	51	interface.\r
2c8dcbc6	52	\r
d055601e LE	53	@param[in] Size Size in bytes to transfer or skip.\r
	54	\r
	55	@param[in,out] Buffer Buffer to read data into or write data from. Ignored,\r
	56	and may be NULL, if Size is zero, or Control is\r
	57	FW_CFG_DMA_CTL_SKIP.\r
	58	\r
	59	@param[in] Control One of the following:\r
	60	FW_CFG_DMA_CTL_WRITE - write to fw_cfg from Buffer.\r
	61	FW_CFG_DMA_CTL_READ - read from fw_cfg into Buffer.\r
	62	FW_CFG_DMA_CTL_SKIP - skip bytes in fw_cfg.\r
2c8dcbc6 LE	63	**/\r
	64	VOID\r
	65	InternalQemuFwCfgDmaBytes (\r
	66	IN UINT32 Size,\r
	67	IN OUT VOID *Buffer OPTIONAL,\r
d055601e	68	IN UINT32 Control\r
2c8dcbc6 LE	69	)\r
	70	{\r
	71	volatile FW_CFG_DMA_ACCESS Access;\r
	72	UINT32 AccessHigh, AccessLow;\r
	73	UINT32 Status;\r
	74	\r
d055601e LE	75	ASSERT (Control == FW_CFG_DMA_CTL_WRITE \|\| Control == FW_CFG_DMA_CTL_READ \|\|\r
	76	Control == FW_CFG_DMA_CTL_SKIP);\r
	77	\r
2c8dcbc6 LE	78	if (Size == 0) {\r
	79	return;\r
	80	}\r
	81	\r
d055601e	82	Access.Control = SwapBytes32 (Control);\r
2c8dcbc6 LE	83	Access.Length = SwapBytes32 (Size);\r
	84	Access.Address = SwapBytes64 ((UINTN)Buffer);\r
	85	\r
	86	//\r
	87	// Delimit the transfer from (a) modifications to Access, (b) in case of a\r
	88	// write, from writes to Buffer by the caller.\r
	89	//\r
	90	MemoryFence ();\r
	91	\r
	92	//\r
	93	// Start the transfer.\r
	94	//\r
	95	AccessHigh = (UINT32)RShiftU64 ((UINTN)&Access, 32);\r
	96	AccessLow = (UINT32)(UINTN)&Access;\r
	97	IoWrite32 (0x514, SwapBytes32 (AccessHigh));\r
	98	IoWrite32 (0x518, SwapBytes32 (AccessLow));\r
	99	\r
	100	//\r
	101	// Don't look at Access.Control before starting the transfer.\r
	102	//\r
	103	MemoryFence ();\r
	104	\r
	105	//\r
	106	// Wait for the transfer to complete.\r
	107	//\r
	108	do {\r
	109	Status = SwapBytes32 (Access.Control);\r
	110	ASSERT ((Status & FW_CFG_DMA_CTL_ERROR) == 0);\r
	111	} while (Status != 0);\r
	112	\r
	113	//\r
	114	// After a read, the caller will want to use Buffer.\r
	115	//\r
	116	MemoryFence ();\r
	117	}\r
	118	\r
	119	\r
f1ec65ba	120	/**\r
	121	Reads firmware configuration bytes into a buffer\r
	122	\r
	123	@param[in] Size - Size in bytes to read\r
	124	@param[in] Buffer - Buffer to store data into (OPTIONAL if Size is 0)\r
	125	\r
	126	**/\r
	127	VOID\r
	128	EFIAPI\r
	129	InternalQemuFwCfgReadBytes (\r
	130	IN UINTN Size,\r
	131	IN VOID *Buffer OPTIONAL\r
	132	)\r
	133	{\r
2c8dcbc6	134	if (InternalQemuFwCfgDmaIsAvailable () && Size <= MAX_UINT32) {\r
d055601e	135	InternalQemuFwCfgDmaBytes ((UINT32)Size, Buffer, FW_CFG_DMA_CTL_READ);\r
2c8dcbc6 LE	136	return;\r
2c8dcbc6 LE	137	}\r
f1ec65ba	138	IoReadFifo8 (0x511, Size, Buffer);\r
	139	}\r
	140	\r
	141	\r
	142	/**\r
	143	Reads firmware configuration bytes into a buffer\r
	144	\r
	145	If called multiple times, then the data read will\r
	146	continue at the offset of the firmware configuration\r
	147	item where the previous read ended.\r
	148	\r
	149	@param[in] Size - Size in bytes to read\r
	150	@param[in] Buffer - Buffer to store data into\r
	151	\r
	152	**/\r
	153	VOID\r
	154	EFIAPI\r
	155	QemuFwCfgReadBytes (\r
	156	IN UINTN Size,\r
	157	IN VOID *Buffer\r
	158	)\r
	159	{\r
0dc231c9	160	if (InternalQemuFwCfgIsAvailable ()) {\r
f1ec65ba	161	InternalQemuFwCfgReadBytes (Size, Buffer);\r
	162	} else {\r
	163	ZeroMem (Buffer, Size);\r
	164	}\r
	165	}\r
	166	\r
29874a8c	167	/**\r
	168	Write firmware configuration bytes from a buffer\r
	169	\r
	170	If called multiple times, then the data written will\r
	171	continue at the offset of the firmware configuration\r
	172	item where the previous write ended.\r
	173	\r
	174	@param[in] Size - Size in bytes to write\r
	175	@param[in] Buffer - Buffer to read data from\r
	176	\r
	177	**/\r
	178	VOID\r
	179	EFIAPI\r
	180	QemuFwCfgWriteBytes (\r
	181	IN UINTN Size,\r
	182	IN VOID *Buffer\r
	183	)\r
	184	{\r
0dc231c9	185	if (InternalQemuFwCfgIsAvailable ()) {\r
2c8dcbc6	186	if (InternalQemuFwCfgDmaIsAvailable () && Size <= MAX_UINT32) {\r
d055601e	187	InternalQemuFwCfgDmaBytes ((UINT32)Size, Buffer, FW_CFG_DMA_CTL_WRITE);\r
2c8dcbc6 LE	188	return;\r
2c8dcbc6 LE	189	}\r
29874a8c	190	IoWriteFifo8 (0x511, Size, Buffer);\r
	191	}\r
	192	}\r
	193	\r
f1ec65ba	194	\r
	195	/**\r
	196	Reads a UINT8 firmware configuration value\r
	197	\r
	198	@return Value of Firmware Configuration item read\r
	199	\r
	200	**/\r
	201	UINT8\r
	202	EFIAPI\r
	203	QemuFwCfgRead8 (\r
	204	VOID\r
	205	)\r
	206	{\r
	207	UINT8 Result;\r
	208	\r
	209	QemuFwCfgReadBytes (sizeof (Result), &Result);\r
	210	\r
	211	return Result;\r
	212	}\r
	213	\r
	214	\r
	215	/**\r
	216	Reads a UINT16 firmware configuration value\r
	217	\r
	218	@return Value of Firmware Configuration item read\r
	219	\r
	220	**/\r
	221	UINT16\r
	222	EFIAPI\r
	223	QemuFwCfgRead16 (\r
	224	VOID\r
	225	)\r
	226	{\r
	227	UINT16 Result;\r
	228	\r
	229	QemuFwCfgReadBytes (sizeof (Result), &Result);\r
	230	\r
	231	return Result;\r
	232	}\r
	233	\r
	234	\r
	235	/**\r
	236	Reads a UINT32 firmware configuration value\r
	237	\r
	238	@return Value of Firmware Configuration item read\r
	239	\r
	240	**/\r
	241	UINT32\r
	242	EFIAPI\r
	243	QemuFwCfgRead32 (\r
	244	VOID\r
	245	)\r
	246	{\r
	247	UINT32 Result;\r
	248	\r
	249	QemuFwCfgReadBytes (sizeof (Result), &Result);\r
	250	\r
	251	return Result;\r
	252	}\r
	253	\r
	254	\r
	255	/**\r
	256	Reads a UINT64 firmware configuration value\r
	257	\r
258	@return Value of Firmware Configuration item read\r
259	\r
260	**/\r
261	UINT64\r
262	EFIAPI\r
263	QemuFwCfgRead64 (\r
264	VOID\r
265	)\r
266	{\r
267	UINT64 Result;\r
268	\r
269	QemuFwCfgReadBytes (sizeof (Result), &Result);\r
270	\r
271	return Result;\r
272	}\r
273	\r
274	\r
0ac9bc9b	275	/**\r
	276	Find the configuration item corresponding to the firmware configuration file.\r
	277	\r
	278	@param[in] Name - Name of file to look up.\r
	279	@param[out] Item - Configuration item corresponding to the file, to be passed\r
	280	to QemuFwCfgSelectItem ().\r
	281	@param[out] Size - Number of bytes in the file.\r
	282	\r
	283	@return RETURN_SUCCESS If file is found.\r
	284	RETURN_NOT_FOUND If file is not found.\r
	285	RETURN_UNSUPPORTED If firmware configuration is unavailable.\r
	286	\r
	287	**/\r
	288	RETURN_STATUS\r
	289	EFIAPI\r
	290	QemuFwCfgFindFile (\r
	291	IN CONST CHAR8 *Name,\r
	292	OUT FIRMWARE_CONFIG_ITEM *Item,\r
	293	OUT UINTN *Size\r
	294	)\r
	295	{\r
	296	UINT32 Count;\r
	297	UINT32 Idx;\r
	298	\r
0dc231c9	299	if (!InternalQemuFwCfgIsAvailable ()) {\r
0ac9bc9b	300	return RETURN_UNSUPPORTED;\r
	301	}\r
	302	\r
	303	QemuFwCfgSelectItem (QemuFwCfgItemFileDir);\r
	304	Count = SwapBytes32 (QemuFwCfgRead32 ());\r
	305	\r
	306	for (Idx = 0; Idx < Count; ++Idx) {\r
	307	UINT32 FileSize;\r
	308	UINT16 FileSelect;\r
	309	UINT16 FileReserved;\r
6a904296	310	CHAR8 FName[QEMU_FW_CFG_FNAME_SIZE];\r
0ac9bc9b	311	\r
	312	FileSize = QemuFwCfgRead32 ();\r
	313	FileSelect = QemuFwCfgRead16 ();\r
	314	FileReserved = QemuFwCfgRead16 ();\r
c6910aed	315	(VOID) FileReserved; /* Force a do-nothing reference. */\r
0ac9bc9b	316	InternalQemuFwCfgReadBytes (sizeof (FName), FName);\r
	317	\r
	318	if (AsciiStrCmp (Name, FName) == 0) {\r
	319	*Item = SwapBytes16 (FileSelect);\r
	320	*Size = SwapBytes32 (FileSize);\r
	321	return RETURN_SUCCESS;\r
	322	}\r
	323	}\r
	324	\r
	325	return RETURN_NOT_FOUND;\r
	326	}\r
14eb7a5b LE	327	\r
	328	\r
	329	/**\r
	330	Determine if S3 support is explicitly enabled.\r
	331	\r
	332	@retval TRUE if S3 support is explicitly enabled.\r
	333	FALSE otherwise. This includes unavailability of the firmware\r
	334	configuration interface.\r
	335	**/\r
	336	BOOLEAN\r
	337	EFIAPI\r
	338	QemuFwCfgS3Enabled (\r
	339	VOID\r
	340	)\r
	341	{\r
	342	RETURN_STATUS Status;\r
	343	FIRMWARE_CONFIG_ITEM FwCfgItem;\r
	344	UINTN FwCfgSize;\r
	345	UINT8 SystemStates[6];\r
	346	\r
	347	Status = QemuFwCfgFindFile ("etc/system-states", &FwCfgItem, &FwCfgSize);\r
	348	if (Status != RETURN_SUCCESS \|\| FwCfgSize != sizeof SystemStates) {\r
	349	return FALSE;\r
	350	}\r
	351	QemuFwCfgSelectItem (FwCfgItem);\r
	352	QemuFwCfgReadBytes (sizeof SystemStates, SystemStates);\r
	353	return (BOOLEAN) (SystemStates[3] & BIT7);\r
	354	}\r