On Mon, Feb 19, 2018 at 09:43:32AM +0000, Ard Biesheuvel wrote:
> This adds support for using the random number generator in the Atmel
> AtSha204a over I2C. Other functionality of the chip is currently
> unsupported.
> 
> Note that the the I2C support in this device essentially violates the
> protocol layering, by requiring that the device is woken up by driving
> SDA low for a certain amount of time, which is something that cannot be
> expressed in terms of an I2C packet sent to the device's slave address.
> Instead, the slave address 0x0 is added to the device's address array,
> and the wake is sent by sending a dummy write to address 0x0, and
> ignoring the subsequent error. This requires the I2C bus to be clocked
> at 100 kHz.

As long as the violation is down to the component rather than its
integration onto the mezzanine board, I see no problem with this.

> Contributed-under: TianoCore Contribution Agreement 1.1
> Signed-off-by: Ard Biesheuvel <ard.biesheu...@linaro.org>
> ---
>  Silicon/Atmel/AtSha204a/AtSha204a.dec     |  22 ++
>  Silicon/Atmel/AtSha204a/AtSha204aDriver.c | 308 ++++++++++++++++++++
>  Silicon/Atmel/AtSha204a/AtSha204aDriver.h |  81 +++++
>  Silicon/Atmel/AtSha204a/AtSha204aDxe.inf  |  52 ++++
>  Silicon/Atmel/AtSha204a/ComponentName.c   | 186 ++++++++++++
>  Silicon/Atmel/AtSha204a/DriverBinding.c   | 242 +++++++++++++++
>  6 files changed, 891 insertions(+)
> 
> diff --git a/Silicon/Atmel/AtSha204a/AtSha204a.dec 
> b/Silicon/Atmel/AtSha204a/AtSha204a.dec
> new file mode 100644
> index 000000000000..f1fdea59843d
> --- /dev/null
> +++ b/Silicon/Atmel/AtSha204a/AtSha204a.dec
> @@ -0,0 +1,22 @@
> +## @file
> +#
> +#  Copyright (c) 2018, 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]
> +  DEC_SPECIFICATION              = 0x0001001A
> +  PACKAGE_NAME                   = AtSha204a
> +  PACKAGE_GUID                   = 86085a5b-355b-4e72-92ab-fc3e1d71c9ad
> +  PACKAGE_VERSION                = 0.1
> +
> +[Guids]
> +  gAtSha204aI2cDeviceGuid = { 0x52e9b64b, 0x4ec1, 0x4bd6, { 0x9e, 0x1c, 
> 0x6d, 0xac, 0xef, 0x35, 0x18, 0x21 } }
> diff --git a/Silicon/Atmel/AtSha204a/AtSha204aDriver.c 
> b/Silicon/Atmel/AtSha204a/AtSha204aDriver.c
> new file mode 100644
> index 000000000000..25329086592a
> --- /dev/null
> +++ b/Silicon/Atmel/AtSha204a/AtSha204aDriver.c
> @@ -0,0 +1,308 @@
> +/** @file
> +  Device driver for the Atmel ATSHA204A random number generator.
> +
> +  Copyright (c) 2018, 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 "AtSha204aDriver.h"
> +
> +#include <Library/BaseMemoryLib.h>
> +#include <Library/DebugLib.h>
> +#include <Library/MemoryAllocationLib.h>
> +
> +#define MAX_RETRIES                 5
> +
> +// Don't bother calculating the CRC for the immutable RANDOM opcode packet
> +#define OPCODE_COMMAND_PACKET_CRC   0xcd24
> +
> +/**
> +  Returns information about the random number generation implementation.
> +
> +  @param[in]     This               A pointer to the EFI_RNG_PROTOCOL 
> instance.
> +  @param[in,out] AlgorithmListSize  On input, the size in bytes of 
> AlgorithmList
> +                                    On output with a return code of 
> EFI_SUCCESS,
> +                                    the size in bytes of the data returned in
> +                                    AlgorithmList. On output with a return
> +                                    code of EFI_BUFFER_TOO_SMALL, the size of
> +                                    AlgorithmList required to obtain the 
> list.
> +  @param[out] AlgorithmList         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
> +AtSha240aGetInfo (
> +  IN      EFI_RNG_PROTOCOL    *This,
> +  IN  OUT UINTN               *AlgorithmListSize,
> +  OUT     EFI_RNG_ALGORITHM   *AlgorithmList
> +)
> +{
> +  UINTN Size;
> +
> +  //
> +  // We only implement the raw algorithm
> +  //
> +  Size = sizeof gEfiRngAlgorithmRaw;

Use parantheses for sizeof?
Also, can this be different from sizeof (EFI_GUID)?

> +
> +  if (*AlgorithmListSize < Size) {
> +    *AlgorithmListSize = Size;
> +    return EFI_BUFFER_TOO_SMALL;
> +  }
> +
> +  gBS->CopyMem (AlgorithmList, &gEfiRngAlgorithmRaw, Size);

You already pull in BaseMemoryLib, so could use CopyGuid?

> +  *AlgorithmListSize = Size;
> +
> +  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]  Algorithm           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]  ValueLength         The length in bytes of the memory buffer
> +                                  pointed to by RNGValue. The driver shall
> +                                  return exactly this numbers of bytes.
> +  @param[out] Value               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
> +AtSha240aGetRNG (
> +  IN EFI_RNG_PROTOCOL   *This,
> +  IN EFI_RNG_ALGORITHM  *Algorithm OPTIONAL,
> +  IN UINTN              ValueLength,
> +  OUT UINT8             *Value
> +)
> +{
> +  EFI_STATUS                  Status;
> +  ATSHA204A_DEV               *AtSha204a;
> +  ATSHA204A_I2C_RNG_COMMAND   Cmd;
> +  ATSHA204A_I2C_RNG_RESULT    Res;
> +  I2C_RNG_REQUEST             Req;
> +  I2C_RNG_REQUEST             Resp;

Since I just gave Marcin a hard time over non-approved abbreviations,
I should probably flag these too... Would you mind terribly turning
them into Command, Result, Request, Response?

> +  UINTN                       Retries;
> +
> +  if (Algorithm != NULL && !CompareGuid (Algorithm, &gEfiRngAlgorithmRaw)) {
> +    return EFI_UNSUPPORTED;
> +  }
> +
> +  AtSha204a = ATSHA204A_DEV_FROM_THIS (This);
> +
> +  Req.OperationCount  = 1;
> +  Req.Operation.Flags = 0;
> +
> +  Cmd.Command   = ATSHA204A_COMMAND;
> +  Cmd.Count     = sizeof (Cmd) - 1;
> +  Cmd.Opcode    = ATSHA204A_OPCODE_RANDOM;
> +  Cmd.Param1    = 0;
> +  Cmd.Param2    = 0;
> +  Cmd.Crc       = OPCODE_COMMAND_PACKET_CRC;
> +
> +  Resp.OperationCount           = 1;
> +  Resp.Operation.Flags          = I2C_FLAG_READ;
> +  Resp.Operation.LengthInBytes  = sizeof (Res);
> +  Resp.Operation.Buffer         = (VOID *)&Res;
> +
> +  Retries = 0;
> +  while (ValueLength > 0) {
> +    //
> +    // The AtSha204a will go back to sleep right in the middle of a 
> transaction
> +    // if it does not complete in ~1.3 seconds. So send the wake sequence for
> +    // each iteration, which consists of a dummy write to slave address 0x0.
> +    //
> +    Req.Operation.LengthInBytes = 0;
> +    Status = AtSha204a->I2cIo->QueueRequest (AtSha204a->I2cIo, 1, NULL,
> +                                 (VOID *)&Req, NULL);
> +    DEBUG ((DEBUG_INFO, "%a: wake AtSha204a: I2cIo->QueueRequest() - %r\n",
> +      __FUNCTION__, Status));
> +
> +    gBS->Stall (2500); // wait 2.5 ms for wake to complete
> +
> +    Req.Operation.LengthInBytes = sizeof (Cmd);
> +    Req.Operation.Buffer = (VOID *)&Cmd;
> +    Status = AtSha204a->I2cIo->QueueRequest (AtSha204a->I2cIo, 0, NULL,
> +                                 (VOID *)&Req, NULL);
> +    if (EFI_ERROR (Status)) {
> +      if (++Retries <= MAX_RETRIES) {
> +        continue;
> +      }
> +      DEBUG ((DEBUG_ERROR, "%a: I2C request transfer failed, Status == %r\n",
> +        __FUNCTION__, Status));
> +      return EFI_DEVICE_ERROR;
> +    }
> +
> +    gBS->Stall (50 * 1000); // 50 ms max execution time for RANDOM opcode

Is there no way of polling for response complete?
50ms per iteration?? :(  (or, well, 52.5 in total)

/
    Leif

> +
> +    Status = AtSha204a->I2cIo->QueueRequest (AtSha204a->I2cIo, 0, NULL,
> +                                 (VOID *)&Resp, NULL);
> +    if (EFI_ERROR (Status)) {
> +      if (++Retries <= MAX_RETRIES) {
> +        continue;
> +      }
> +      DEBUG ((DEBUG_ERROR, "%a: I2C response transfer failed, Status == 
> %r\n",
> +        __FUNCTION__, Status));
> +      return EFI_DEVICE_ERROR;
> +    }
> +
> +    if (Res.Count < sizeof (Res)) {
> +      //
> +      // Incomplete packet received, most likely due to an error. Retry.
> +      //
> +      if (++Retries <= MAX_RETRIES) {
> +        continue;
> +      }
> +      DEBUG ((DEBUG_WARN, "%a: incomplete packet received\n", __FUNCTION__));
> +      return EFI_DEVICE_ERROR;
> +    }
> +
> +    gBS->CopyMem (Value, Res.Result, MIN (ValueLength, 
> ATSHA204A_OUTPUT_SIZE));
> +    if (ValueLength < ATSHA204A_OUTPUT_SIZE) {
> +      break;
> +    }
> +
> +    Value += ATSHA204A_OUTPUT_SIZE;
> +    ValueLength -= ATSHA204A_OUTPUT_SIZE;
> +    Retries = 0;
> +  }
> +  return EFI_SUCCESS;
> +}
> +
> +EFI_STATUS
> +AtSha204aInit (
> +  IN      EFI_HANDLE        DriverBindingHandle,
> +  IN      EFI_HANDLE        ControllerHandle
> +  )
> +{
> +  EFI_STATUS                Status;
> +  ATSHA204A_DEV             *AtSha204a;
> +
> +  Status = gBS->AllocatePool (EfiBootServicesData, sizeof (ATSHA204A_DEV),
> +                  (VOID **) &AtSha204a);
> +  if (EFI_ERROR (Status)) {
> +    return EFI_OUT_OF_RESOURCES;
> +  }
> +
> +  AtSha204a->Signature    = ATSHA204A_DEV_SIGNATURE;
> +  AtSha204a->Rng.GetInfo  = AtSha240aGetInfo;
> +  AtSha204a->Rng.GetRNG   = AtSha240aGetRNG;
> +
> +  //
> +  // Open I2C I/O Protocol
> +  //
> +  Status = gBS->OpenProtocol (ControllerHandle,
> +                              &gEfiI2cIoProtocolGuid,
> +                              (VOID **)&AtSha204a->I2cIo,
> +                              DriverBindingHandle,
> +                              ControllerHandle,
> +                              EFI_OPEN_PROTOCOL_BY_DRIVER);
> +  if (EFI_ERROR (Status)) {
> +    goto ErrorFreeDev;
> +  }
> +
> +  Status = gBS->InstallProtocolInterface (&ControllerHandle,
> +                                          &gEfiRngProtocolGuid,
> +                                          EFI_NATIVE_INTERFACE,
> +                                          &AtSha204a->Rng);
> +  if (EFI_ERROR (Status)) {
> +    DEBUG ((DEBUG_ERROR,
> +      "Failed to install RNG protocol interface (Status == %r)\n",
> +    Status));
> +    goto ErrorCloseProtocol;
> +  }
> +
> +  return EFI_SUCCESS;
> +
> +ErrorCloseProtocol:
> +  gBS->CloseProtocol (ControllerHandle, &gEfiI2cIoProtocolGuid,
> +         DriverBindingHandle, ControllerHandle);
> +
> +ErrorFreeDev:
> +  gBS->FreePool (AtSha204a);
> +
> +  return Status;
> +}
> +
> +EFI_STATUS
> +AtSha204aRelease (
> +  IN  EFI_HANDLE        DriverBindingHandle,
> +  IN  EFI_HANDLE        ControllerHandle
> +  )
> +{
> +  EFI_RNG_PROTOCOL    *Rng;
> +  ATSHA204A_DEV       *AtSha204a;
> +  EFI_STATUS          Status;
> +
> +  Status = gBS->HandleProtocol (ControllerHandle,
> +                                &gEfiRngProtocolGuid,
> +                                (VOID **)&Rng);
> +  ASSERT_EFI_ERROR (Status);
> +  if (EFI_ERROR (Status)) {
> +    return Status;
> +  }
> +
> +  AtSha204a = ATSHA204A_DEV_FROM_THIS (Rng);
> +
> +  Status = gBS->UninstallProtocolInterface (ControllerHandle,
> +                                            &gEfiRngProtocolGuid,
> +                                            Rng);
> +  ASSERT_EFI_ERROR (Status);
> +  if (EFI_ERROR (Status)) {
> +    return Status;
> +  }
> +
> +  Status = gBS->CloseProtocol (ControllerHandle,
> +                               &gEfiI2cIoProtocolGuid,
> +                               DriverBindingHandle,
> +                               ControllerHandle);
> +  ASSERT_EFI_ERROR (Status);
> +  if (EFI_ERROR (Status)) {
> +    return Status;
> +  }
> +
> +  gBS->FreePool (AtSha204a);
> +
> +  return EFI_SUCCESS;
> +}
> diff --git a/Silicon/Atmel/AtSha204a/AtSha204aDriver.h 
> b/Silicon/Atmel/AtSha204a/AtSha204aDriver.h
> new file mode 100644
> index 000000000000..315a450d34f2
> --- /dev/null
> +++ b/Silicon/Atmel/AtSha204a/AtSha204aDriver.h
> @@ -0,0 +1,81 @@
> +/** @file
> +  Device driver for the Atmel ATSHA204A random number generator.
> +
> +  Copyright (c) 2018, 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.
> +
> +**/
> +
> +#ifndef _ATSHA204A_I2C_HWRNG_DRIVER_H_
> +#define _ATSHA204A_I2C_HWRNG_DRIVER_H_
> +
> +#include <Uefi.h>
> +#include <Library/BaseMemoryLib.h>
> +#include <Library/DebugLib.h>
> +#include <Library/UefiBootServicesTableLib.h>
> +#include <Library/UefiLib.h>
> +
> +#include <Protocol/Rng.h>
> +#include <Protocol/I2cIo.h>
> +
> +#define ATSHA204A_OUTPUT_SIZE     32
> +
> +#define ATSHA204A_DEV_SIGNATURE   SIGNATURE_32('a','t','s','h')
> +
> +typedef struct {
> +  UINT32                        Signature;
> +  EFI_I2C_IO_PROTOCOL           *I2cIo;
> +  EFI_RNG_PROTOCOL              Rng;
> +} ATSHA204A_DEV;
> +
> +#define ATSHA204A_DEV_FROM_THIS(a) \
> +  CR(a, ATSHA204A_DEV, Rng, ATSHA204A_DEV_SIGNATURE)
> +
> +#pragma pack(1)
> +typedef struct {
> +  UINT8                           Command;
> +  UINT8                           Count;
> +  UINT8                           Opcode;
> +  UINT8                           Param1;
> +  UINT16                          Param2;
> +  UINT16                          Crc;
> +} ATSHA204A_I2C_RNG_COMMAND;
> +
> +typedef struct {
> +  UINT8                           Count;
> +  UINT8                           Result[ATSHA204A_OUTPUT_SIZE];
> +  UINT16                          Crc;
> +} ATSHA204A_I2C_RNG_RESULT;
> +#pragma pack()
> +
> +typedef struct {
> +  UINTN                           OperationCount;
> +  EFI_I2C_OPERATION               Operation;
> +} I2C_RNG_REQUEST;
> +
> +#define ATSHA204A_COMMAND         0x3
> +
> +#define ATSHA204A_OPCODE_RANDOM   0x1b
> +
> +extern EFI_COMPONENT_NAME2_PROTOCOL gAtSha204aDriverComponentName2;
> +
> +EFI_STATUS
> +AtSha204aInit (
> +  IN  EFI_HANDLE        DriverBindingHandle,
> +  IN  EFI_HANDLE        ControllerHandle
> +  );
> +
> +EFI_STATUS
> +AtSha204aRelease (
> +  IN  EFI_HANDLE        DriverBindingHandle,
> +  IN  EFI_HANDLE        ControllerHandle
> +  );
> +
> +#endif // _ATSHA204A_I2C_HWRNG_DRIVER_H_
> diff --git a/Silicon/Atmel/AtSha204a/AtSha204aDxe.inf 
> b/Silicon/Atmel/AtSha204a/AtSha204aDxe.inf
> new file mode 100644
> index 000000000000..fe90cc538114
> --- /dev/null
> +++ b/Silicon/Atmel/AtSha204a/AtSha204aDxe.inf
> @@ -0,0 +1,52 @@
> +## @file
> +#  Device driver for the Atmel ATSHA204A random number generator.
> +#
> +#  Copyright (c) 2018, 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.
> +#
> +##
> +
> +[Defines]
> +  INF_VERSION                    = 0x0001001A
> +  BASE_NAME                      = AtSha204aDxe
> +  FILE_GUID                      = 8b8f683b-f376-4ba0-b8d7-b4bbd30319cc
> +  MODULE_TYPE                    = UEFI_DRIVER
> +  VERSION_STRING                 = 1.0
> +  ENTRY_POINT                    = EntryPoint
> +  UNLOAD_IMAGE                   = UnloadImage
> +
> +#
> +#  VALID_ARCHITECTURES           = AARCH64 ARM EBC IA32 IPF X64
> +#
> +
> +[Sources]
> +  AtSha204aDriver.c
> +  AtSha204aDriver.h
> +  ComponentName.c
> +  DriverBinding.c
> +
> +[Packages]
> +  MdePkg/MdePkg.dec
> +  Silicon/Atmel/AtSha204a/AtSha204a.dec
> +
> +[LibraryClasses]
> +  BaseMemoryLib
> +  DebugLib
> +  UefiBootServicesTableLib
> +  UefiDriverEntryPoint
> +  UefiLib
> +
> +[Protocols]
> +  gEfiRngProtocolGuid                 # PROTOCOL BY_START
> +  gEfiI2cIoProtocolGuid               # PROTOCOL TO_START
> +
> +[Guids]
> +  gAtSha204aI2cDeviceGuid
> +  gEfiRngAlgorithmRaw
> diff --git a/Silicon/Atmel/AtSha204a/ComponentName.c 
> b/Silicon/Atmel/AtSha204a/ComponentName.c
> new file mode 100644
> index 000000000000..9893e7c4c2bf
> --- /dev/null
> +++ b/Silicon/Atmel/AtSha204a/ComponentName.c
> @@ -0,0 +1,186 @@
> +/** @file
> +  UEFI Component Name(2) protocol implementation for AtSha204a driver.
> +
> +  Copyright (c) 2018, 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.
> +
> +**/
> +
> +#include "AtSha204aDriver.h"
> +
> +STATIC EFI_UNICODE_STRING_TABLE mAtSha204aDriverNameTable[] = {
> +  {
> +    "en",
> +    (CHAR16 *)L"AtSha204a RNG I2C driver"
> +  },
> +  { }
> +};
> +
> +STATIC EFI_UNICODE_STRING_TABLE mAtSha204aControllerNameTable[] = {
> +  {
> +    "en",
> +    (CHAR16 *)L"AtSha204a Random Number Generator (I2C)"
> +  },
> +  { }
> +};
> +
> +/**
> +  Retrieves a Unicode string that is the user readable name of the driver.
> +
> +  This function retrieves the user readable name of a driver in the form of a
> +  Unicode string. If the driver specified by This has a user readable name in
> +  the language specified by Language, then a pointer to the driver name is
> +  returned in DriverName, and EFI_SUCCESS is returned. If the driver 
> specified
> +  by This does not support the language specified by Language,
> +  then EFI_UNSUPPORTED is returned.
> +
> +  @param  This[in]              A pointer to the 
> EFI_COMPONENT_NAME2_PROTOCOL or
> +                                EFI_COMPONENT_NAME_PROTOCOL instance.
> +
> +  @param  Language[in]          A pointer to a Null-terminated ASCII string
> +                                array indicating the language. This is the
> +                                language of the driver name that the caller 
> is
> +                                requesting, and it must match one of the
> +                                languages specified in SupportedLanguages. 
> The
> +                                number of languages supported by a driver is 
> up
> +                                to the driver writer. Language is specified
> +                                in RFC 4646 or ISO 639-2 language code 
> format.
> +
> +  @param  DriverName[out]       A pointer to the Unicode string to return.
> +                                This Unicode string is the name of the
> +                                driver specified by This in the language
> +                                specified by Language.
> +
> +  @retval EFI_SUCCESS           The Unicode string for the Driver specified 
> by
> +                                This and the language specified by Language 
> was
> +                                returned in DriverName.
> +
> +  @retval EFI_INVALID_PARAMETER Language is NULL.
> +
> +  @retval EFI_INVALID_PARAMETER DriverName is NULL.
> +
> +  @retval EFI_UNSUPPORTED       The driver specified by This does not support
> +                                the language specified by Language.
> +
> +**/
> +STATIC
> +EFI_STATUS
> +EFIAPI
> +AtSha204aGetDriverName (
> +  IN  EFI_COMPONENT_NAME2_PROTOCOL  *This,
> +  IN  CHAR8                         *Language,
> +  OUT CHAR16                        **DriverName
> +  )
> +{
> +  return LookupUnicodeString2 (Language,
> +                               This->SupportedLanguages,
> +                               mAtSha204aDriverNameTable,
> +                               DriverName,
> +                               FALSE);
> +}
> +
> +/**
> +  Retrieves a Unicode string that is the user readable name of the controller
> +  that is being managed by a driver.
> +
> +  This function retrieves the user readable name of the controller specified 
> by
> +  ControllerHandle and ChildHandle in the form of a Unicode string. If the
> +  driver specified by This has a user readable name in the language 
> specified by
> +  Language, then a pointer to the controller name is returned in 
> ControllerName,
> +  and EFI_SUCCESS is returned.  If the driver specified by This is not 
> currently
> +  managing the controller specified by ControllerHandle and ChildHandle,
> +  then EFI_UNSUPPORTED is returned.  If the driver specified by This does not
> +  support the language specified by Language, then EFI_UNSUPPORTED is 
> returned.
> +
> +  @param  This[in]              A pointer to the 
> EFI_COMPONENT_NAME2_PROTOCOL or
> +                                EFI_COMPONENT_NAME_PROTOCOL instance.
> +
> +  @param  ControllerHandle[in]  The handle of a controller that the driver
> +                                specified by This is managing.  This handle
> +                                specifies the controller whose name is to be
> +                                returned.
> +
> +  @param  ChildHandle[in]       The handle of the child controller to 
> retrieve
> +                                the name of.  This is an optional parameter 
> that
> +                                may be NULL.  It will be NULL for device
> +                                drivers.  It will also be NULL for a bus 
> drivers
> +                                that wish to retrieve the name of the bus
> +                                controller.  It will not be NULL for a bus
> +                                driver that wishes to retrieve the name of a
> +                                child controller.
> +
> +  @param  Language[in]          A pointer to a Null-terminated ASCII string
> +                                array indicating the language.  This is the
> +                                language of the driver name that the caller 
> is
> +                                requesting, and it must match one of the
> +                                languages specified in SupportedLanguages. 
> The
> +                                number of languages supported by a driver is 
> up
> +                                to the driver writer. Language is specified 
> in
> +                                RFC 4646 or ISO 639-2 language code format.
> +
> +  @param  ControllerName[out]   A pointer to the Unicode string to return.
> +                                This Unicode string is the name of the
> +                                controller specified by ControllerHandle and
> +                                ChildHandle in the language specified by
> +                                Language from the point of view of the driver
> +                                specified by This.
> +
> +  @retval EFI_SUCCESS           The Unicode string for the user readable 
> name in
> +                                the language specified by Language for the
> +                                driver specified by This was returned in
> +                                DriverName.
> +
> +  @retval EFI_INVALID_PARAMETER ControllerHandle is NULL.
> +
> +  @retval EFI_INVALID_PARAMETER ChildHandle is not NULL and it is not a valid
> +                                EFI_HANDLE.
> +
> +  @retval EFI_INVALID_PARAMETER Language is NULL.
> +
> +  @retval EFI_INVALID_PARAMETER ControllerName is NULL.
> +
> +  @retval EFI_UNSUPPORTED       The driver specified by This is not currently
> +                                managing the controller specified by
> +                                ControllerHandle and ChildHandle.
> +
> +  @retval EFI_UNSUPPORTED       The driver specified by This does not support
> +                                the language specified by Language.
> +
> +**/
> +STATIC
> +EFI_STATUS
> +EFIAPI
> +AtSha204aGetControllerName (
> +  IN  EFI_COMPONENT_NAME2_PROTOCOL                    *This,
> +  IN  EFI_HANDLE                                      ControllerHandle,
> +  IN  EFI_HANDLE                                      ChildHandle        
> OPTIONAL,
> +  IN  CHAR8                                           *Language,
> +  OUT CHAR16                                          **ControllerName
> +  )
> +{
> +  if (ChildHandle != NULL) {
> +    return EFI_UNSUPPORTED;
> +  }
> +
> +  return LookupUnicodeString2 (Language,
> +                               This->SupportedLanguages,
> +                               mAtSha204aControllerNameTable,
> +                               ControllerName,
> +                               FALSE);
> +}
> +
> +//
> +// EFI Component Name 2 Protocol
> +//
> +EFI_COMPONENT_NAME2_PROTOCOL gAtSha204aDriverComponentName2 = {
> +  AtSha204aGetDriverName,
> +  AtSha204aGetControllerName,
> +  "en"
> +};
> diff --git a/Silicon/Atmel/AtSha204a/DriverBinding.c 
> b/Silicon/Atmel/AtSha204a/DriverBinding.c
> new file mode 100644
> index 000000000000..17e61f96e8c5
> --- /dev/null
> +++ b/Silicon/Atmel/AtSha204a/DriverBinding.c
> @@ -0,0 +1,242 @@
> +/** @file
> +  Device driver for the Atmel ATSHA204A random number generator.
> +
> +  Copyright (c) 2018, 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/UefiDriverEntryPoint.h>
> +
> +#include "AtSha204aDriver.h"
> +
> +/**
> +  Tests to see if this driver supports a given controller.
> +
> +  @param  This[in]                 A pointer to the 
> EFI_DRIVER_BINDING_PROTOCOL
> +                                   instance.
> +  @param  ControllerHandle[in]     The handle of the controller to test.
> +  @param  RemainingDevicePath[in]  The remaining device path.
> +                                   (Ignored - this is not a bus driver.)
> +
> +  @retval EFI_SUCCESS              The driver supports this controller.
> +  @retval EFI_ALREADY_STARTED      The device specified by ControllerHandle 
> is
> +                                   already being managed by the driver 
> specified
> +                                   by This.
> +  @retval EFI_UNSUPPORTED          The device specified by ControllerHandle 
> is
> +                                   not supported by the driver specified by 
> This.
> +
> +**/
> +EFI_STATUS
> +EFIAPI
> +I2cHwrngDriverBindingSupported (
> +  IN EFI_DRIVER_BINDING_PROTOCOL  *This,
> +  IN EFI_HANDLE                   ControllerHandle,
> +  IN EFI_DEVICE_PATH_PROTOCOL     *RemainingDevicePath
> +  )
> +{
> +  EFI_I2C_IO_PROTOCOL        *I2cIo;
> +  EFI_STATUS                 Status;
> +
> +  //
> +  //  Connect to the I2C stack
> +  //
> +  Status = gBS->OpenProtocol (ControllerHandle,
> +                              &gEfiI2cIoProtocolGuid,
> +                              (VOID **) &I2cIo,
> +                              This->DriverBindingHandle,
> +                              ControllerHandle,
> +                              EFI_OPEN_PROTOCOL_BY_DRIVER);
> +  if (EFI_ERROR (Status)) {
> +    return Status;
> +  }
> +
> +  if (CompareGuid (I2cIo->DeviceGuid, &gAtSha204aI2cDeviceGuid)) {
> +    DEBUG ((DEBUG_INIT | DEBUG_INFO, "Detected AtSha204a RNG device\n"));
> +    Status = EFI_SUCCESS;
> +  } else {
> +    Status = EFI_UNSUPPORTED;
> +  }
> +
> +  //
> +  // Clean up.
> +  //
> +  gBS->CloseProtocol (ControllerHandle,
> +                      &gEfiI2cIoProtocolGuid,
> +                      This->DriverBindingHandle,
> +                      ControllerHandle);
> +
> +  return Status;
> +}
> +
> +
> +/**
> +  Starts a device controller or a bus controller.
> +
> +  @param[in]  This                 A pointer to the 
> EFI_DRIVER_BINDING_PROTOCOL
> +                                   instance.
> +  @param[in]  ControllerHandle     The handle of the device to start. This
> +                                   handle must support a protocol interface 
> that
> +                                   supplies an I/O abstraction to the driver.
> +  @param[in]  RemainingDevicePath  The remaining portion of the device path.
> +                                   (Ignored - this is not a bus driver.)
> +
> +  @retval EFI_SUCCESS              The device was started.
> +  @retval EFI_DEVICE_ERROR         The device could not be started due to a
> +                                   device error.
> +  @retval EFI_OUT_OF_RESOURCES     The request could not be completed due to 
> a
> +                                   lack of resources.
> +
> +**/
> +EFI_STATUS
> +EFIAPI
> +I2cHwrngDriverBindingStart (
> +  IN EFI_DRIVER_BINDING_PROTOCOL  *This,
> +  IN EFI_HANDLE                   ControllerHandle,
> +  IN EFI_DEVICE_PATH_PROTOCOL     *RemainingDevicePath OPTIONAL
> +  )
> +{
> +  return AtSha204aInit (This->DriverBindingHandle, ControllerHandle);
> +}
> +
> +
> +/**
> +  Stops a device controller or a bus controller.
> +
> +  @param[in]  This              A pointer to the EFI_DRIVER_BINDING_PROTOCOL
> +                                instance.
> +  @param[in]  ControllerHandle  A handle to the device being stopped. The 
> handle
> +                                must support a bus specific I/O protocol for 
> the
> +                                driver to use to stop the device.
> +  @param[in]  NumberOfChildren  The number of child device handles in
> +                                ChildHandleBuffer.
> +  @param[in]  ChildHandleBuffer An array of child handles to be freed. May be
> +                                NULL if NumberOfChildren is 0.
> +
> +  @retval EFI_SUCCESS           The device was stopped.
> +  @retval EFI_DEVICE_ERROR      The device could not be stopped due to a 
> device
> +                                error.
> +
> +**/
> +EFI_STATUS
> +EFIAPI
> +I2cHwrngDriverBindingStop (
> +  IN  EFI_DRIVER_BINDING_PROTOCOL  *This,
> +  IN  EFI_HANDLE                  ControllerHandle,
> +  IN  UINTN                       NumberOfChildren,
> +  IN  EFI_HANDLE                  *ChildHandleBuffer OPTIONAL
> +  )
> +{
> +  return AtSha204aRelease (This->DriverBindingHandle, ControllerHandle);
> +}
> +
> +
> +STATIC
> +EFI_DRIVER_BINDING_PROTOCOL  gI2cHwrngDriverBinding = {
> +  I2cHwrngDriverBindingSupported,
> +  I2cHwrngDriverBindingStart,
> +  I2cHwrngDriverBindingStop,
> +  0xa,
> +  NULL,
> +  NULL
> +};
> +
> +
> +/**
> +  The entry point of AtSha204a UEFI Driver.
> +
> +  @param  ImageHandle                The image handle of the UEFI Driver.
> +  @param  SystemTable                A pointer to the EFI System Table.
> +
> +  @retval  EFI_SUCCESS               The Driver or UEFI Driver exited 
> normally.
> +  @retval  EFI_INCOMPATIBLE_VERSION  _gUefiDriverRevision is greater than
> +                                     SystemTable->Hdr.Revision.
> +
> +**/
> +EFI_STATUS
> +EFIAPI
> +EntryPoint (
> +  IN  EFI_HANDLE          ImageHandle,
> +  IN  EFI_SYSTEM_TABLE    *SystemTable
> +  )
> +{
> +  EFI_STATUS    Status;
> +
> +  //
> +  //  Add the driver to the list of drivers
> +  //
> +  Status = EfiLibInstallDriverBindingComponentName2 (
> +             ImageHandle, SystemTable, &gI2cHwrngDriverBinding, ImageHandle,
> +             NULL, &gAtSha204aDriverComponentName2);
> +  ASSERT_EFI_ERROR (Status);
> +
> +  DEBUG ((DEBUG_INIT | DEBUG_INFO, "*** Installed AtSha204a driver! ***\n"));
> +
> +  return EFI_SUCCESS;
> +}
> +
> +
> +/**
> +  Unload function for the AtSha204a Driver.
> +
> +  @param  ImageHandle[in]        The allocated handle for the EFI image
> +
> +  @retval EFI_SUCCESS            The driver was unloaded successfully
> +  @retval EFI_INVALID_PARAMETER  ImageHandle is not a valid image handle.
> +
> +**/
> +EFI_STATUS
> +EFIAPI
> +UnloadImage (
> +  IN EFI_HANDLE  ImageHandle
> +  )
> +{
> +  EFI_STATUS  Status;
> +  EFI_HANDLE  *HandleBuffer;
> +  UINTN       HandleCount;
> +  UINTN       Index;
> +
> +  //
> +  // Retrieve all I2C I/O handles in the handle database
> +  //
> +  Status = gBS->LocateHandleBuffer (ByProtocol,
> +                                    &gEfiI2cIoProtocolGuid,
> +                                    NULL,
> +                                    &HandleCount,
> +                                    &HandleBuffer);
> +  if (EFI_ERROR (Status)) {
> +    return Status;
> +  }
> +
> +  //
> +  // Disconnect the driver from the handles in the handle database
> +  //
> +  for (Index = 0; Index < HandleCount; Index++) {
> +    Status = gBS->DisconnectController (HandleBuffer[Index],
> +                                        gImageHandle,
> +                                        NULL);
> +  }
> +
> +  //
> +  // Free the handle array
> +  //
> +  gBS->FreePool (HandleBuffer);
> +
> +  //
> +  // Uninstall protocols installed by the driver in its entrypoint
> +  //
> +  Status = gBS->UninstallMultipleProtocolInterfaces (ImageHandle,
> +                  &gEfiDriverBindingProtocolGuid,
> +                  &gI2cHwrngDriverBinding,
> +                  NULL
> +                  );
> +
> +  return EFI_SUCCESS;
> +}
> -- 
> 2.11.0
> 
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