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/** @file
This driver produces an EFI_RNG_PROTOCOL instance for the Armada 70x0 TRNG
Copyright (C) 2017, 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/IoLib.h>
#include <Library/PcdLib.h>
#include <Library/UefiBootServicesTableLib.h>
#include <Protocol/Rng.h>
#define TRNG_OUTPUT_REG mTrngBaseAddress
#define TRNG_OUTPUT_SIZE 0x10
#define TRNG_STATUS_REG (mTrngBaseAddress + 0x10)
#define TRNG_STATUS_READY BIT0
#define TRNG_INTACK_REG (mTrngBaseAddress + 0x10)
#define TRNG_INTACK_READY BIT0
#define TRNG_CONTROL_REG (mTrngBaseAddress + 0x14)
#define TRNG_CONTROL_REG_ENABLE BIT10
#define TRNG_CONFIG_REG (mTrngBaseAddress + 0x18)
#define __MIN_REFILL_SHIFT 0
#define __MAX_REFILL_SHIFT 16
#define TRNG_CONFIG_MIN_REFILL_CYCLES (0x05 << __MIN_REFILL_SHIFT)
#define TRNG_CONFIG_MAX_REFILL_CYCLES (0x22 << __MAX_REFILL_SHIFT)
#define TRNG_FRODETUNE_REG (mTrngBaseAddress + 0x24)
#define TRNG_FRODETUNE_MASK 0x0
#define TRNG_FROENABLE_REG (mTrngBaseAddress + 0x20)
#define TRNG_FROENABLE_MASK 0xffffff
#define TRNG_MAX_RETRIES 20
STATIC EFI_PHYSICAL_ADDRESS mTrngBaseAddress;
/**
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
Armada7k8kRngGetInfo (
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;
}
STATIC
EFI_STATUS
GetTrngData (
IN UINTN Length,
OUT UINT8 *Bits
)
{
UINTN Tries;
UINT32 Buf[TRNG_OUTPUT_SIZE / sizeof (UINT32)];
UINTN Index;
for (Tries = 0; Tries < TRNG_MAX_RETRIES; Tries++) {
if (MmioRead32 (TRNG_STATUS_REG) & TRNG_STATUS_READY) {
for (Index = 0; Index < ARRAY_SIZE (Buf); Index++) {
Buf[Index] = MmioRead32 (TRNG_OUTPUT_REG + Index * sizeof (UINT32));
}
CopyMem (Bits, Buf, Length);
MmioWrite32 (TRNG_INTACK_REG, TRNG_INTACK_READY);
return EFI_SUCCESS;
}
// Wait for more TRNG data to arrive
gBS->Stall (10);
}
return EFI_DEVICE_ERROR;
}
/**
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
Armada7k8kRngGetRNG (
IN EFI_RNG_PROTOCOL *This,
IN EFI_RNG_ALGORITHM *RNGAlgorithm, OPTIONAL
IN UINTN RNGValueLength,
OUT UINT8 *RNGValue
)
{
UINTN Length;
EFI_STATUS Status;
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 {
Length = MIN (RNGValueLength, TRNG_OUTPUT_SIZE);
Status = GetTrngData (Length, RNGValue);
if (EFI_ERROR (Status)) {
return Status;
}
RNGValue += Length;
RNGValueLength -= Length;
} while (RNGValueLength > 0);
return EFI_SUCCESS;
}
STATIC EFI_RNG_PROTOCOL mArmada7k8kRngProtocol = {
Armada7k8kRngGetInfo,
Armada7k8kRngGetRNG
};
//
// Entry point of this driver.
//
EFI_STATUS
EFIAPI
Armada7k8kRngDxeEntryPoint (
IN EFI_HANDLE ImageHandle,
IN EFI_SYSTEM_TABLE *SystemTable
)
{
mTrngBaseAddress = PcdGet64 (PcdEip76TrngBaseAddress);
//
// Disable the TRNG before updating its configuration
//
MmioAnd32 (TRNG_CONTROL_REG, ~TRNG_CONTROL_REG_ENABLE);
//
// Configure the internal conditioning parameters of the TRNG
//
MmioWrite32 (TRNG_CONFIG_REG, TRNG_CONFIG_MIN_REFILL_CYCLES |
TRNG_CONFIG_MAX_REFILL_CYCLES);
//
// Configure the FROs
//
MmioWrite32 (TRNG_FRODETUNE_REG, TRNG_FRODETUNE_MASK);
MmioWrite32 (TRNG_FROENABLE_REG, TRNG_FROENABLE_MASK);
//
// Enable the TRNG
//
MmioOr32 (TRNG_CONTROL_REG, TRNG_CONTROL_REG_ENABLE);
return SystemTable->BootServices->InstallMultipleProtocolInterfaces (
&ImageHandle,
&gEfiRngProtocolGuid,
&mArmada7k8kRngProtocol,
NULL
);
}
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