* [PATCH edk2-platforms 1/2] Silicon/Bcm2836: add random number generator driver
2019-02-16 10:34 [PATCH edk2-platforms 0/2] Platform/RaspberryPi3: add RNG support Ard Biesheuvel
@ 2019-02-16 10:34 ` Ard Biesheuvel
2019-02-16 10:34 ` [PATCH edk2-platforms 2/2] Platform/RaspberryPi3: add RNG driver Ard Biesheuvel
2019-02-19 14:44 ` [PATCH edk2-platforms 0/2] Platform/RaspberryPi3: add RNG support Leif Lindholm
2 siblings, 0 replies; 5+ messages in thread
From: Ard Biesheuvel @ 2019-02-16 10:34 UTC (permalink / raw)
To: edk2-devel
Expose the SoC's RNG peripheral via the EFI_RNG_PROTOCOL.
This is used by Linux to seed the KASLR routines.
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
---
Silicon/Broadcom/Bcm283x/Drivers/RngDxe/RngDxe.c | 203 ++++++++++++++++++++
Silicon/Broadcom/Bcm283x/Drivers/RngDxe/RngDxe.inf | 45 +++++
Silicon/Broadcom/Bcm283x/Include/IndustryStandard/Bcm2836.h | 9 +
3 files changed, 257 insertions(+)
diff --git a/Silicon/Broadcom/Bcm283x/Drivers/RngDxe/RngDxe.c b/Silicon/Broadcom/Bcm283x/Drivers/RngDxe/RngDxe.c
new file mode 100644
index 000000000000..399d93158547
--- /dev/null
+++ b/Silicon/Broadcom/Bcm283x/Drivers/RngDxe/RngDxe.c
@@ -0,0 +1,203 @@
+/** @file
+
+ This driver produces an EFI_RNG_PROTOCOL instance for the Broadcom 2836 RNG
+
+ Copyright (C) 2019, 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/BaseLib.h>
+#include <Library/BaseMemoryLib.h>
+#include <Library/DebugLib.h>
+#include <Library/IoLib.h>
+#include <Library/UefiBootServicesTableLib.h>
+
+#include <IndustryStandard/Bcm2836.h>
+
+#include <Protocol/Rng.h>
+
+#define RNG_WARMUP_COUNT 0x40000
+#define RNG_MAX_RETRIES 0x100 // arbitrary upper bound
+
+/**
+ 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
+Bcm2836RngGetInfo (
+ 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
+Bcm2836RngGetRNG (
+ IN EFI_RNG_PROTOCOL *This,
+ IN EFI_RNG_ALGORITHM *RNGAlgorithm, OPTIONAL
+ IN UINTN RNGValueLength,
+ OUT UINT8 *RNGValue
+ )
+{
+ UINT32 Val;
+ UINT32 Num;
+ UINT32 Retries;
+
+ 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;
+ }
+
+ while (RNGValueLength > 0) {
+ Retries = RNG_MAX_RETRIES;
+ do {
+ Num = MmioRead32 (RNG_STATUS) >> 24;
+ MemoryFence ();
+ } while (!Num && Retries-- > 0);
+
+ if (!Num) {
+ return EFI_DEVICE_ERROR;
+ }
+
+ while (RNGValueLength >= sizeof (UINT32) && Num > 0) {
+ WriteUnaligned32 ((VOID *)RNGValue, MmioRead32 (RNG_DATA));
+ RNGValue += sizeof (UINT32);
+ RNGValueLength -= sizeof (UINT32);
+ Num--;
+ }
+
+ if (RNGValueLength > 0 && Num > 0) {
+ Val = MmioRead32 (RNG_DATA);
+ while (RNGValueLength--) {
+ *RNGValue++ = (UINT8)Val;
+ Val >>= 8;
+ }
+ }
+ }
+ return EFI_SUCCESS;
+}
+
+STATIC EFI_RNG_PROTOCOL mBcm2836RngProtocol = {
+ Bcm2836RngGetInfo,
+ Bcm2836RngGetRNG
+};
+
+//
+// Entry point of this driver.
+//
+EFI_STATUS
+EFIAPI
+Bcm2836RngEntryPoint (
+ IN EFI_HANDLE ImageHandle,
+ IN EFI_SYSTEM_TABLE *SystemTable
+ )
+{
+ EFI_STATUS Status;
+
+ Status = gBS->InstallMultipleProtocolInterfaces (&ImageHandle,
+ &gEfiRngProtocolGuid, &mBcm2836RngProtocol,
+ NULL);
+ ASSERT_EFI_ERROR (Status);
+
+ MmioWrite32 (RNG_STATUS, RNG_WARMUP_COUNT);
+ MmioWrite32 (RNG_CTRL, RNG_CTRL_ENABLE);
+
+ return EFI_SUCCESS;
+}
diff --git a/Silicon/Broadcom/Bcm283x/Drivers/RngDxe/RngDxe.inf b/Silicon/Broadcom/Bcm283x/Drivers/RngDxe/RngDxe.inf
new file mode 100644
index 000000000000..45e8825244f7
--- /dev/null
+++ b/Silicon/Broadcom/Bcm283x/Drivers/RngDxe/RngDxe.inf
@@ -0,0 +1,45 @@
+#/** @file
+#
+# Copyright (c) 2019 Linaro, Ltd. All rights reserved.
+#
+# 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.
+#
+#**/
+
+[Defines]
+ INF_VERSION = 0x0001001B
+ BASE_NAME = RngDxe
+ FILE_GUID = 9743084e-c82a-4714-b2ba-f571f81cb021
+ MODULE_TYPE = DXE_DRIVER
+ VERSION_STRING = 1.0
+ ENTRY_POINT = Bcm2836RngEntryPoint
+
+[Sources]
+ RngDxe.c
+
+[Packages]
+ MdePkg/MdePkg.dec
+ Silicon/Broadcom/Bcm283x/Bcm283x.dec
+
+[LibraryClasses]
+ BaseLib
+ BaseMemoryLib
+ DebugLib
+ IoLib
+ UefiBootServicesTableLib
+ UefiDriverEntryPoint
+
+[Protocols]
+ gEfiRngProtocolGuid ## PRODUCES
+
+[Guids]
+ gEfiRngAlgorithmRaw
+
+[Depex]
+ TRUE
diff --git a/Silicon/Broadcom/Bcm283x/Include/IndustryStandard/Bcm2836.h b/Silicon/Broadcom/Bcm283x/Include/IndustryStandard/Bcm2836.h
index f9fffb764649..f06eb2312c61 100644
--- a/Silicon/Broadcom/Bcm283x/Include/IndustryStandard/Bcm2836.h
+++ b/Silicon/Broadcom/Bcm283x/Include/IndustryStandard/Bcm2836.h
@@ -69,4 +69,13 @@
#define BCM2836_INTC_TIMER_CONTROL_OFFSET 0x00000040
#define BCM2836_INTC_TIMER_PENDING_OFFSET 0x00000060
+/* random number generator */
+#define RNG_BASE_ADDRESS (BCM2836_SOC_REGISTERS + 0x00104000)
+
+#define RNG_CTRL (RNG_BASE_ADDRESS + 0x0)
+#define RNG_STATUS (RNG_BASE_ADDRESS + 0x4)
+#define RNG_DATA (RNG_BASE_ADDRESS + 0x8)
+
+#define RNG_CTRL_ENABLE 0x1
+
#endif /*__BCM2836_H__ */
--
2.20.1
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