diff options
Diffstat (limited to 'Silicon/AMD/Styx/Drivers/StyxRngDxe/StyxRngDxe.c')
| -rw-r--r-- | Silicon/AMD/Styx/Drivers/StyxRngDxe/StyxRngDxe.c | 189 |
1 files changed, 189 insertions, 0 deletions
diff --git a/Silicon/AMD/Styx/Drivers/StyxRngDxe/StyxRngDxe.c b/Silicon/AMD/Styx/Drivers/StyxRngDxe/StyxRngDxe.c new file mode 100644 index 0000000000..be6cf9eda5 --- /dev/null +++ b/Silicon/AMD/Styx/Drivers/StyxRngDxe/StyxRngDxe.c @@ -0,0 +1,189 @@ +/** @file
+
+ This driver produces an EFI_RNG_PROTOCOL instance for the AMD Seattle CCP
+
+ Copyright (C) 2016, Linaro Ltd. All rights reserved.<BR>
+
+ This program and the accompanying materials are licensed and made available
+ under the terms and conditions of the BSD License which accompanies this
+ distribution. The full text of the license may be found at
+ http://opensource.org/licenses/bsd-license.php
+
+ THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS, WITHOUT
+ WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
+
+**/
+
+#include <Library/BaseMemoryLib.h>
+#include <Library/PcdLib.h>
+#include <Library/IoLib.h>
+
+#include <Protocol/Rng.h>
+
+#define CCP_TRNG_OFFSET 0xc
+#define CCP_TNRG_RETRIES 5
+
+STATIC EFI_PHYSICAL_ADDRESS mCcpRngOutputReg;
+
+STATIC EFI_HANDLE mHandle;
+
+/**
+ Returns information about the random number generation implementation.
+
+ @param[in] This A pointer to the EFI_RNG_PROTOCOL
+ instance.
+ @param[in,out] RNGAlgorithmListSize On input, the size in bytes of
+ RNGAlgorithmList.
+ On output with a return code of
+ EFI_SUCCESS, the size in bytes of the
+ data returned in RNGAlgorithmList. On
+ output with a return code of
+ EFI_BUFFER_TOO_SMALL, the size of
+ RNGAlgorithmList required to obtain the
+ list.
+ @param[out] RNGAlgorithmList A caller-allocated memory buffer filled
+ by the driver with one EFI_RNG_ALGORITHM
+ element for each supported RNG algorithm.
+ The list must not change across multiple
+ calls to the same driver. The first
+ algorithm in the list is the default
+ algorithm for the driver.
+
+ @retval EFI_SUCCESS The RNG algorithm list was returned
+ successfully.
+ @retval EFI_UNSUPPORTED The services is not supported by this
+ driver.
+ @retval EFI_DEVICE_ERROR The list of algorithms could not be
+ retrieved due to a hardware or firmware
+ error.
+ @retval EFI_INVALID_PARAMETER One or more of the parameters are
+ incorrect.
+ @retval EFI_BUFFER_TOO_SMALL The buffer RNGAlgorithmList is too small
+ to hold the result.
+
+**/
+STATIC
+EFI_STATUS
+EFIAPI
+StyxRngGetInfo (
+ IN EFI_RNG_PROTOCOL *This,
+ IN OUT UINTN *RNGAlgorithmListSize,
+ OUT EFI_RNG_ALGORITHM *RNGAlgorithmList
+ )
+{
+ if (This == NULL || RNGAlgorithmListSize == NULL) {
+ return EFI_INVALID_PARAMETER;
+ }
+
+ if (*RNGAlgorithmListSize < sizeof (EFI_RNG_ALGORITHM)) {
+ *RNGAlgorithmListSize = sizeof (EFI_RNG_ALGORITHM);
+ return EFI_BUFFER_TOO_SMALL;
+ }
+
+ if (RNGAlgorithmList == NULL) {
+ return EFI_INVALID_PARAMETER;
+ }
+
+ *RNGAlgorithmListSize = sizeof (EFI_RNG_ALGORITHM);
+ CopyGuid (RNGAlgorithmList, &gEfiRngAlgorithmRaw);
+
+ return EFI_SUCCESS;
+}
+
+/**
+ Produces and returns an RNG value using either the default or specified RNG
+ algorithm.
+
+ @param[in] This A pointer to the EFI_RNG_PROTOCOL
+ instance.
+ @param[in] RNGAlgorithm A pointer to the EFI_RNG_ALGORITHM that
+ identifies the RNG algorithm to use. May
+ be NULL in which case the function will
+ use its default RNG algorithm.
+ @param[in] RNGValueLength The length in bytes of the memory buffer
+ pointed to by RNGValue. The driver shall
+ return exactly this numbers of bytes.
+ @param[out] RNGValue A caller-allocated memory buffer filled
+ by the driver with the resulting RNG
+ value.
+
+ @retval EFI_SUCCESS The RNG value was returned successfully.
+ @retval EFI_UNSUPPORTED The algorithm specified by RNGAlgorithm
+ is not supported by this driver.
+ @retval EFI_DEVICE_ERROR An RNG value could not be retrieved due
+ to a hardware or firmware error.
+ @retval EFI_NOT_READY There is not enough random data available
+ to satisfy the length requested by
+ RNGValueLength.
+ @retval EFI_INVALID_PARAMETER RNGValue is NULL or RNGValueLength is
+ zero.
+
+**/
+STATIC
+EFI_STATUS
+EFIAPI
+StyxRngGetRNG (
+ IN EFI_RNG_PROTOCOL *This,
+ IN EFI_RNG_ALGORITHM *RNGAlgorithm, OPTIONAL
+ IN UINTN RNGValueLength,
+ OUT UINT8 *RNGValue
+ )
+{
+ UINT32 Val;
+ UINT32 Retries;
+ UINT32 Loop;
+
+ if (This == NULL || RNGValueLength == 0 || RNGValue == NULL) {
+ return EFI_INVALID_PARAMETER;
+ }
+
+ //
+ // We only support the raw algorithm, so reject requests for anything else
+ //
+ if (RNGAlgorithm != NULL &&
+ !CompareGuid (RNGAlgorithm, &gEfiRngAlgorithmRaw)) {
+ return EFI_UNSUPPORTED;
+ }
+
+ do {
+ Retries = CCP_TNRG_RETRIES;
+ do {
+ Val = MmioRead32 (mCcpRngOutputReg);
+ } while (!Val && Retries-- > 0);
+
+ if (!Val) {
+ return EFI_DEVICE_ERROR;
+ }
+
+ for (Loop = 0; Loop < 4 && RNGValueLength > 0; Loop++, RNGValueLength--) {
+ *RNGValue++ = (UINT8)Val;
+ Val >>= 8;
+ }
+ } while (RNGValueLength > 0);
+
+ return EFI_SUCCESS;
+}
+
+STATIC EFI_RNG_PROTOCOL mStyxRngProtocol = {
+ StyxRngGetInfo,
+ StyxRngGetRNG
+};
+
+//
+// Entry point of this driver.
+//
+EFI_STATUS
+EFIAPI
+StyxRngEntryPoint (
+ IN EFI_HANDLE ImageHandle,
+ IN EFI_SYSTEM_TABLE *SystemTable
+ )
+{
+ mCcpRngOutputReg = PcdGet64 (PcdCCPBase) + CCP_TRNG_OFFSET;
+
+ return SystemTable->BootServices->InstallMultipleProtocolInterfaces (
+ &mHandle,
+ &gEfiRngProtocolGuid, &mStyxRngProtocol,
+ NULL
+ );
+}
|