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/** @file
Implement EFI Random Number Generator runtime services via Rng Lib.
Copyright (c) 2008 - 2009, Apple Inc. 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 <Uefi.h>
#include <Library/IoLib.h>
#include <Library/PcdLib.h>
#include <Library/DebugLib.h>
#include <Library/ArmGicLib.h>
#include <Library/BaseMemoryLib.h>
#include <Library/UefiBootServicesTableLib.h>
#include <Protocol/ExynosRng.h>
#include "RngDxe.h"
#define CLKDIV 512
#define RNGSEL 5
/**
* Generates a pseudorandom byte stream of the specified size.
*
* If Output is NULL, then return FALSE.
*
* @param[out] Output Pointer to buffer to receive random value
* @param[in] Size Size of random bytes to generate
*
* @retval TRUE Pseudorandom byte stream generated successfully.
* @retval FALSE Pseudorandom number generator fails to generate due to lack of entropy.
*
**/
EFI_STATUS
EFIAPI
RngDxeRandomBytes (
IN CONST EFI_RNG_PROTOCOL *This,
OUT UINT8 *Output,
IN UINTN Size
)
{
EFI_STATUS Status = EFI_SUCCESS;
UINT32 TRNGBase;
UINT32 value, count, fifo_addr;
TRNGBase = PcdGet32(PcdCryptoBase);
/* Set Clock Divider */
MmioWrite32(TRNGBase + TRNG_CLKDIV, CLKDIV);
/* Select RNG Engine */
value = TRNG_ENABLE | TRNG_MANUAL_ENABLE | RNGSEL;
MmioWrite32(TRNGBase + TRNG_CTRL, value);
/* Select and Enable Post Processor */
value = TRNG_POST_ENABLE | TRNG_POST_SEL_LFSR;
MmioWrite32(TRNGBase + TRNG_POST_CTRL, value);
/* Disable Online Tester */
MmioWrite32(TRNGBase + TRNG_ONLINE_CTRL, 0);
/* Set FIFO pointer as number of random bits */
MmioWrite32(TRNGBase + TRNG_FIFO_CTRL, Size << 3);
/* Poll FIFO pointer until TRNG_FIFO_CTRL.FIFOPTR == 0 */
while (MmioRead32(TRNGBase + TRNG_FIFO_CTRL));
/* Read TRNG FIFO */
for (count = 0; count < (Size >> 2); count++) {
fifo_addr = TRNG_FIFO_0 + (count << 2);
value = MmioRead32(TRNGBase + fifo_addr);
CopyMem((UINT8 *)((UINT32)Output + (count << 2)), &value, sizeof(value));
}
return Status;
}
EFI_RNG_PROTOCOL gRng = {
RngDxeRandomBytes
};
/**
Initialize the state information for the RngDxe
@param ImageHandle of the loaded driver
@param SystemTable Pointer to the System Table
@retval EFI_SUCCESS Protocol registered
@retval EFI_OUT_OF_RESOURCES Cannot allocate protocol data structure
@retval EFI_DEVICE_ERROR Hardware problems
**/
EFI_STATUS
EFIAPI
RngDxeInitialize (
IN EFI_HANDLE ImageHandle,
IN EFI_SYSTEM_TABLE *SystemTable
)
{
EFI_STATUS Status = EFI_SUCCESS;
Status = gBS->InstallMultipleProtocolInterfaces(
&ImageHandle,
&gSamsungPlatformRngProtocolGuid,
&gRng,
NULL
);
return Status;
}
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