ArmPkg/ArmScmiDxe: Dynamically allocate buffer for protocol ids

Dynamically allocate the buffer to receive the SCMI protocol list.
This makes MAX_PROTOCOLS redundant, so it is removed.
It also fixes one minor code alignment issue and removes an unused
macro PROTOCOL_MASK.

Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Girish Pathak <girish.pathak@arm.com>
Tested-by: Sudeep Holla <sudeep.holla@arm.com>
Reviewed-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>

ArmPkg/Drivers/ArmScmiDxe/Scmi.c

@@ -22,11 +22,6 @@
 
 #include "ScmiPrivate.h"
 
-// SCMI Specification 1.0
-#define  MAX_PROTOCOLS       6
-
-#define  PROTOCOL_MASK     0xF
-
 // Arbitrary timeout value 20ms.
 #define  RESPONSE_TIMEOUT  20000
 

ArmPkg/Drivers/ArmScmiDxe/ScmiDxe.c

@@ -63,8 +63,8 @@ ArmScmiDxeEntryPoint (
   UINT32              Index;
   UINT32              NumProtocols;
   UINT32              ProtocolIndex;
-  UINT8               SupportedList[MAX_PROTOCOLS];
-  UINT32              SupportedListSize = sizeof (SupportedList);
+  UINT8               *SupportedList;
+  UINT32              SupportedListSize;
 
   // Every SCMI implementation must implement the base protocol.
   ASSERT (Protocols[0].Id == SCMI_PROTOCOL_ID_BASE);
@@ -108,13 +108,26 @@ ArmScmiDxeEntryPoint (
 
   ASSERT (NumProtocols != 0);
 
+  SupportedListSize = (NumProtocols * sizeof (*SupportedList));
+
+  Status = gBS->AllocatePool (
+                  EfiBootServicesData,
+                  SupportedListSize,
+                  (VOID**)&SupportedList
+                  );
+  if (EFI_ERROR (Status)) {
+    ASSERT (FALSE);
+    return Status;
+  }
+
   // Get the list of protocols supported by SCP firmware on the platform.
   Status = BaseProtocol->DiscoverListProtocols (
-             BaseProtocol,
-             &SupportedListSize,
-             SupportedList
-             );
+                           BaseProtocol,
+                           &SupportedListSize,
+                           SupportedList
+                           );
   if (EFI_ERROR (Status)) {
+    gBS->FreePool (SupportedList);
     ASSERT (FALSE);
     return Status;
   }
@@ -134,5 +147,7 @@ ArmScmiDxeEntryPoint (
     }
   }
 
+  gBS->FreePool (SupportedList);
+
   return EFI_SUCCESS;
 }

ArmPkg/Drivers/ArmScmiDxe/ScmiDxe.h

@@ -19,7 +19,6 @@
 
 #include "ScmiPrivate.h"
 
-#define MAX_PROTOCOLS        6
 #define MAX_VENDOR_LEN       SCMI_MAX_STR_LEN
 
 /** Pointer to protocol initialization function.