ArmPkg/ArmScmiDxe: Add PERFORMANCE_DESCRIBE_FASTCHANNEL support

The PERFORMANCE_DESCRIBE_FASTCHANNEL Scmi command is available
since SCMI v2.0 and allows to query information about the supported
fast-channels of the Scmi performance protocol.
Add support for this command.

Also move SCMI_MESSAGE_ID_PERFORMANCE enum definition up in the file
to use it in SCMI_PERFORMANCE_DESCRIBE_FASTCHANNEL function
declaration.

Reviewed-by: Leif Lindholm <quic_llindhol@quicinc.com>
Acked-by: Ard Biesheuvel <ardb@kernel.org>
Reviewed-by: Sami Mujawar <sami.mujawar@arm.com>
Signed-off-by: Pierre Gondois <pierre.gondois@arm.com>

ArmPkg/Drivers/ArmScmiDxe/ScmiPerformanceProtocol.c

@@ -1,12 +1,12 @@
 /** @file
 
-  Copyright (c) 2017-2021, Arm Limited. All rights reserved.<BR>
+  Copyright (c) 2017-2023, Arm Limited. All rights reserved.<BR>
 
   SPDX-License-Identifier: BSD-2-Clause-Patent
 
-  System Control and Management Interface V1.0
+  System Control and Management Interface V3.2, latest version at:
-    http://infocenter.arm.com/help/topic/com.arm.doc.den0056a/
+  - https://developer.arm.com/documentation/den0056/latest/
-    DEN0056A_System_Control_and_Management_Interface.pdf
+
 **/
 
 #include <Library/BaseMemoryLib.h>
@@ -416,6 +416,75 @@ PerformanceLevelGet (
   return EFI_SUCCESS;
 }
 
+/** Discover the attributes of the FastChannel for the specified
+    performance domain and the specified message.
+
+  @param[in]  This        A Pointer to SCMI_PERFORMANCE_PROTOCOL Instance.
+  @param[in]  DomainId    Identifier for the performance domain.
+  @param[in]  MessageId   Message Id of the FastChannel to discover.
+                          Must be one of:
+                           - PERFORMANCE_LIMITS_SET
+                           - PERFORMANCE_LIMITS_GET
+                           - PERFORMANCE_LEVEL_SET
+                           - PERFORMANCE_LEVEL_GET
+  @param[out] FastChannel If success, contains the FastChannel description.
+
+  @retval EFI_SUCCESS             Performance level got successfully.
+  @retval EFI_DEVICE_ERROR        SCP returns an SCMI error.
+  @retval EFI_INVALID_PARAMETER   Invalid parameter.
+  @retval EFI_TIMEOUT             Time out.
+  @retval EFI_UNSUPPORTED         Unsupported.
+**/
+EFI_STATUS
+DescribeFastchannel (
+  IN  SCMI_PERFORMANCE_PROTOCOL     *This,
+  IN  UINT32                        DomainId,
+  IN  SCMI_MESSAGE_ID_PERFORMANCE   MessageId,
+  OUT SCMI_PERFORMANCE_FASTCHANNEL  *FastChannel
+  )
+{
+  EFI_STATUS    Status;
+  SCMI_COMMAND  Cmd;
+  UINT32        PayloadLength;
+  UINT32        *ReturnValues;
+  UINT32        *MessageParams;
+
+  if ((This == NULL)  ||
+      (FastChannel == NULL))
+  {
+    return EFI_INVALID_PARAMETER;
+  }
+
+  Status = ScmiCommandGetPayload (&MessageParams);
+  if (EFI_ERROR (Status)) {
+    return Status;
+  }
+
+  *MessageParams++ = DomainId;
+  *MessageParams   = MessageId;
+
+  Cmd.ProtocolId = ScmiProtocolIdPerformance;
+  Cmd.MessageId  = ScmiMessageIdPerformanceDescribeFastchannel;
+  PayloadLength  = sizeof (DomainId) + sizeof (MessageId);
+
+  Status = ScmiCommandExecute (
+             &Cmd,
+             &PayloadLength,
+             &ReturnValues
+             );
+  if (EFI_ERROR (Status)) {
+    return Status;
+  }
+
+  CopyMem (
+    FastChannel,
+    ReturnValues,
+    sizeof (SCMI_PERFORMANCE_FASTCHANNEL)
+    );
+
+  return Status;
+}
+
 // Instance of the SCMI performance management protocol.
 STATIC CONST SCMI_PERFORMANCE_PROTOCOL  PerformanceProtocol = {
   PerformanceGetVersion,
@@ -425,7 +494,8 @@ STATIC CONST SCMI_PERFORMANCE_PROTOCOL  PerformanceProtocol = {
   PerformanceLimitsSet,
   PerformanceLimitsGet,
   PerformanceLevelSet,
-  PerformanceLevelGet
+  PerformanceLevelGet,
+  DescribeFastchannel,
 };
 
 /** Initialize performance management protocol and install on a given Handle.

ArmPkg/Include/Protocol/ArmScmiPerformanceProtocol.h

@@ -79,8 +79,58 @@ typedef struct {
   UINT32    RangeMin;
 } SCMI_PERFORMANCE_LIMITS;
 
+/// Doorbell Support bit.
+#define SCMI_PERF_FC_ATTRIB_HAS_DOORBELL  BIT0
+
+/// Performance protocol describe fastchannel
+typedef struct {
+  /// Attributes.
+  UINT32    Attributes;
+
+  /// Rate limit.
+  UINT32    RateLimit;
+
+  /// Lower 32 bits of the FastChannel address.
+  UINT32    ChanAddrLow;
+
+  /// Higher 32 bits of the FastChannel address.
+  UINT32    ChanAddrHigh;
+
+  /// Size of the FastChannel in bytes.
+  UINT32    ChanSize;
+
+  /// Lower 32 bits of the doorbell address.
+  UINT32    DoorbellAddrLow;
+
+  /// Higher 32 bits of the doorbell address.
+  UINT32    DoorbellAddrHigh;
+
+  /// Mask of lower 32 bits to set when writing to the doorbell register.
+  UINT32    DoorbellSetMaskLow;
+
+  /// Mask of higher 32 bits to set when writing to the doorbell register.
+  UINT32    DoorbellSetMaskHigh;
+
+  /// Mask of lower 32 bits to preserve when writing to the doorbell register.
+  UINT32    DoorbellPreserveMaskLow;
+
+  /// Mask of higher 32 bits to preserve when writing to the doorbell register.
+  UINT32    DoorbellPreserveMaskHigh;
+} SCMI_PERFORMANCE_FASTCHANNEL;
+
 #pragma pack()
 
+/// SCMI Message Ids for the Performance Protocol.
+typedef enum {
+  ScmiMessageIdPerformanceDomainAttributes    = 0x3,
+  ScmiMessageIdPerformanceDescribeLevels      = 0x4,
+  ScmiMessageIdPerformanceLimitsSet           = 0x5,
+  ScmiMessageIdPerformanceLimitsGet           = 0x6,
+  ScmiMessageIdPerformanceLevelSet            = 0x7,
+  ScmiMessageIdPerformanceLevelGet            = 0x8,
+  ScmiMessageIdPerformanceDescribeFastchannel = 0xB,
+} SCMI_MESSAGE_ID_PERFORMANCE;
+
 /** Return version of the performance management protocol supported by SCP.
    firmware.
 
@@ -238,6 +288,34 @@ EFI_STATUS
   OUT UINT32                    *Level
   );
 
+/** Discover the attributes of the FastChannel for the specified
+    performance domain and the specified message.
+
+  @param[in]  This        A Pointer to SCMI_PERFORMANCE_PROTOCOL Instance.
+  @param[in]  DomainId    Identifier for the performance domain.
+  @param[in]  MessageId   Message Id of the FastChannel to discover.
+                          Must be one of:
+                           - PERFORMANCE_LIMITS_SET
+                           - PERFORMANCE_LIMITS_GET
+                           - PERFORMANCE_LEVEL_SET
+                           - PERFORMANCE_LEVEL_GET
+  @param[out] FastChannel If success, contains the FastChannel description.
+
+  @retval EFI_SUCCESS             Performance level got successfully.
+  @retval EFI_DEVICE_ERROR        SCP returns an SCMI error.
+  @retval EFI_INVALID_PARAMETER   Invalid parameter.
+  @retval EFI_TIMEOUT             Time out.
+  @retval EFI_UNSUPPORTED         Unsupported.
+**/
+typedef
+EFI_STATUS
+(EFIAPI *SCMI_PERFORMANCE_DESCRIBE_FASTCHANNEL)(
+  IN  SCMI_PERFORMANCE_PROTOCOL       *This,
+  IN  UINT32                          DomainId,
+  IN  SCMI_MESSAGE_ID_PERFORMANCE     MessageId,
+  OUT SCMI_PERFORMANCE_FASTCHANNEL    *FastChannel
+  );
+
 typedef struct _SCMI_PERFORMANCE_PROTOCOL {
   SCMI_PERFORMANCE_GET_VERSION              GetVersion;
   SCMI_PERFORMANCE_GET_ATTRIBUTES           GetProtocolAttributes;
@@ -247,15 +325,7 @@ typedef struct _SCMI_PERFORMANCE_PROTOCOL {
   SCMI_PERFORMANCE_LIMITS_GET               LimitsGet;
   SCMI_PERFORMANCE_LEVEL_SET                LevelSet;
   SCMI_PERFORMANCE_LEVEL_GET                LevelGet;
+  SCMI_PERFORMANCE_DESCRIBE_FASTCHANNEL     DescribeFastchannel;
 } SCMI_PERFORMANCE_PROTOCOL;
 
-typedef enum {
-  ScmiMessageIdPerformanceDomainAttributes = 0x3,
-  ScmiMessageIdPerformanceDescribeLevels   = 0x4,
-  ScmiMessageIdPerformanceLimitsSet        = 0x5,
-  ScmiMessageIdPerformanceLimitsGet        = 0x6,
-  ScmiMessageIdPerformanceLevelSet         = 0x7,
-  ScmiMessageIdPerformanceLevelGet         = 0x8,
-} SCMI_MESSAGE_ID_PERFORMANCE;
-
 #endif /* ARM_SCMI_PERFORMANCE_PROTOCOL_H_ */