Revision: 18545
http://sourceforge.net/p/edk2/code/18545
Author: lersek
Date: 2015-09-24 21:40:41 +0000 (Thu, 24 Sep 2015)
Log Message:
-----------
ArmVirtPkg: QemuFwCfgLib: read bytes from fw-cfg with DMA when available
The protocol is documented in "docs/specs/fw_cfg.txt" in the QEMU tree.
Cc: Ard Biesheuvel <[email protected]>
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Laszlo Ersek <[email protected]>
Reviewed-by: Ard Biesheuvel <[email protected]>
Modified Paths:
--------------
trunk/edk2/ArmVirtPkg/Library/QemuFwCfgLib/QemuFwCfgLib.c
trunk/edk2/ArmVirtPkg/Library/QemuFwCfgLib/QemuFwCfgLib.inf
Modified: trunk/edk2/ArmVirtPkg/Library/QemuFwCfgLib/QemuFwCfgLib.c
===================================================================
--- trunk/edk2/ArmVirtPkg/Library/QemuFwCfgLib/QemuFwCfgLib.c 2015-09-24
21:40:36 UTC (rev 18544)
+++ trunk/edk2/ArmVirtPkg/Library/QemuFwCfgLib/QemuFwCfgLib.c 2015-09-24
21:40:41 UTC (rev 18545)
@@ -16,14 +16,60 @@
#include <Library/BaseLib.h>
#include <Library/BaseMemoryLib.h>
+#include <Library/DebugLib.h>
#include <Library/IoLib.h>
#include <Library/PcdLib.h>
#include <Library/QemuFwCfgLib.h>
STATIC UINTN mFwCfgSelectorAddress;
STATIC UINTN mFwCfgDataAddress;
+STATIC UINTN mFwCfgDmaAddress;
+/**
+ Reads firmware configuration bytes into a buffer
+ @param[in] Size Size in bytes to read
+ @param[in] Buffer Buffer to store data into (OPTIONAL if Size is 0)
+
+**/
+typedef
+VOID (EFIAPI READ_BYTES_FUNCTION) (
+ IN UINTN Size,
+ IN VOID *Buffer OPTIONAL
+ );
+
+//
+// Forward declaration of the two implementations we have.
+//
+STATIC READ_BYTES_FUNCTION MmioReadBytes;
+STATIC READ_BYTES_FUNCTION DmaReadBytes;
+
+//
+// This points to the one we detect at runtime.
+//
+STATIC READ_BYTES_FUNCTION *InternalQemuFwCfgReadBytes = MmioReadBytes;
+
+//
+// Communication structure for DmaReadBytes(). All fields are encoded in big
+// endian.
+//
+#pragma pack (1)
+typedef struct {
+ UINT32 Control;
+ UINT32 Length;
+ UINT64 Address;
+} FW_CFG_DMA_ACCESS;
+#pragma pack ()
+
+//
+// Macros for the FW_CFG_DMA_ACCESS.Control bitmap (in native encoding).
+//
+#define FW_CFG_DMA_CTL_ERROR BIT0
+#define FW_CFG_DMA_CTL_READ BIT1
+#define FW_CFG_DMA_CTL_SKIP BIT2
+#define FW_CFG_DMA_CTL_SELECT BIT3
+
+
/**
Returns a boolean indicating if the firmware configuration interface is
available for library-internal purposes.
@@ -77,7 +123,22 @@
QemuFwCfgSelectItem (QemuFwCfgItemSignature);
Signature = QemuFwCfgRead32 ();
- if (Signature != SIGNATURE_32 ('Q', 'E', 'M', 'U')) {
+ if (Signature == SIGNATURE_32 ('Q', 'E', 'M', 'U')) {
+ //
+ // For DMA support, we require the DTB to advertise the register, and the
+ // feature bitmap (which we read without DMA) to confirm the feature.
+ //
+ if (PcdGet64 (PcdFwCfgDmaAddress) != 0) {
+ UINT32 Features;
+
+ QemuFwCfgSelectItem (QemuFwCfgItemInterfaceVersion);
+ Features = QemuFwCfgRead32 ();
+ if ((Features & BIT1) != 0) {
+ mFwCfgDmaAddress = PcdGet64 (PcdFwCfgDmaAddress);
+ InternalQemuFwCfgReadBytes = DmaReadBytes;
+ }
+ }
+ } else {
mFwCfgSelectorAddress = 0;
mFwCfgDataAddress = 0;
}
@@ -108,16 +169,12 @@
/**
- Reads firmware configuration bytes into a buffer
-
- @param[in] Size Size in bytes to read
- @param[in] Buffer Buffer to store data into (OPTIONAL if Size is 0)
-
+ Slow READ_BYTES_FUNCTION.
**/
STATIC
VOID
EFIAPI
-InternalQemuFwCfgReadBytes (
+MmioReadBytes (
IN UINTN Size,
IN VOID *Buffer OPTIONAL
)
@@ -163,6 +220,61 @@
/**
+ Fast READ_BYTES_FUNCTION.
+**/
+STATIC
+VOID
+EFIAPI
+DmaReadBytes (
+ IN UINTN Size,
+ IN VOID *Buffer OPTIONAL
+ )
+{
+ volatile FW_CFG_DMA_ACCESS Access;
+ UINT32 Status;
+
+ if (Size == 0) {
+ return;
+ }
+
+ ASSERT (Size <= MAX_UINT32);
+
+ Access.Control = SwapBytes32 (FW_CFG_DMA_CTL_READ);
+ Access.Length = SwapBytes32 ((UINT32)Size);
+ Access.Address = SwapBytes64 ((UINT64)(UINTN)Buffer);
+
+ //
+ // We shouldn't start the transfer before setting up Access.
+ //
+ MemoryFence ();
+
+ //
+ // This will fire off the transfer.
+ //
+#ifdef MDE_CPU_AARCH64
+ MmioWrite64 (mFwCfgDmaAddress, SwapBytes64 ((UINT64)&Access));
+#else
+ MmioWrite32 ((UINT32)(mFwCfgDmaAddress + 4), SwapBytes32 ((UINT32)&Access));
+#endif
+
+ //
+ // We shouldn't look at Access.Control before starting the transfer.
+ //
+ MemoryFence ();
+
+ do {
+ Status = SwapBytes32 (Access.Control);
+ ASSERT ((Status & FW_CFG_DMA_CTL_ERROR) == 0);
+ } while (Status != 0);
+
+ //
+ // The caller will want to access the transferred data.
+ //
+ MemoryFence ();
+}
+
+
+/**
Reads firmware configuration bytes into a buffer
If called multiple times, then the data read will continue at the offset of
Modified: trunk/edk2/ArmVirtPkg/Library/QemuFwCfgLib/QemuFwCfgLib.inf
===================================================================
--- trunk/edk2/ArmVirtPkg/Library/QemuFwCfgLib/QemuFwCfgLib.inf 2015-09-24
21:40:36 UTC (rev 18544)
+++ trunk/edk2/ArmVirtPkg/Library/QemuFwCfgLib/QemuFwCfgLib.inf 2015-09-24
21:40:41 UTC (rev 18545)
@@ -44,9 +44,11 @@
[LibraryClasses]
BaseLib
BaseMemoryLib
+ DebugLib
IoLib
PcdLib
[Pcd]
gArmVirtTokenSpaceGuid.PcdFwCfgSelectorAddress
gArmVirtTokenSpaceGuid.PcdFwCfgDataAddress
+ gArmVirtTokenSpaceGuid.PcdFwCfgDmaAddress
------------------------------------------------------------------------------
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