ArmPkg/ArmScmiDxe: Fix ASSERT error in SCMI DXE

This change fixes a bug in the SCMI DXE which is observed with the
upcoming release of the SCP firmware.

The PROTOCOL_ID_MASK (0xF) which is used to generate an index in
the ProtocolInitFxns is wrong because protocol ids can be
anywhere in 0x10 - 15 or 0x80 - FF range. This mask generates
the same index for two different protocols e.g. for protocol ids
0x10 and 0x90, which causes duplicate initialization of a protocol
resulting in a failure.

This change removes the use of PROTOCOL_ID_MASK and instead
uses a list of protocol ids and their initialization functions
to identify a supported protocol and initialize it.

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>

2 files changed, 23 insertions, 21 deletions

diff --git a/ArmPkg/Drivers/ArmScmiDxe/ScmiDxe.c b/ArmPkg/Drivers/ArmScmiDxe/ScmiDxe.c
index 2920c6f..a56c7b2 100644
--- a/ArmPkg/Drivers/ArmScmiDxe/ScmiDxe.c
+++ b/ArmPkg/Drivers/ArmScmiDxe/ScmiDxe.c
@@ -29,13 +29,10 @@
 #include "ScmiDxe.h"

 #include "ScmiPrivate.h"

 

-STATIC CONST SCMI_PROTOCOL_INIT_TABLE ProtocolInitFxns[MAX_PROTOCOLS] = {

-  { ScmiBaseProtocolInit },

-  { NULL },

-  { NULL },

-  { ScmiPerformanceProtocolInit },

-  { ScmiClockProtocolInit },

-  { NULL }

+STATIC CONST SCMI_PROTOCOL_ENTRY Protocols[] = {

+  { SCMI_PROTOCOL_ID_BASE, ScmiBaseProtocolInit },

+  { SCMI_PROTOCOL_ID_PERFORMANCE, ScmiPerformanceProtocolInit },

+  { SCMI_PROTOCOL_ID_CLOCK, ScmiClockProtocolInit }

 };

 

 /** ARM SCMI driver entry point function.

@@ -65,14 +62,14 @@ ArmScmiDxeEntryPoint (
   UINT32              Version;

   UINT32              Index;

   UINT32              NumProtocols;

-  UINT32              ProtocolNo;

+  UINT32              ProtocolIndex;

   UINT8               SupportedList[MAX_PROTOCOLS];

   UINT32              SupportedListSize = sizeof (SupportedList);

 

-  ProtocolNo = SCMI_PROTOCOL_ID_BASE & PROTOCOL_ID_MASK;

-

   // Every SCMI implementation must implement the base protocol.

-  Status = ProtocolInitFxns[ProtocolNo].Init (&ImageHandle);

+  ASSERT (Protocols[0].Id == SCMI_PROTOCOL_ID_BASE);

+

+  Status = ScmiBaseProtocolInit (&ImageHandle);

   if (EFI_ERROR (Status)) {

     ASSERT (FALSE);

     return Status;

@@ -123,13 +120,16 @@ ArmScmiDxeEntryPoint (
   }

 

   // Install supported protocol on ImageHandle.

-  for (Index = 0; Index < NumProtocols; Index++) {

-    ProtocolNo = SupportedList[Index] & PROTOCOL_ID_MASK;

-    if (ProtocolInitFxns[ProtocolNo].Init != NULL) {

-      Status = ProtocolInitFxns[ProtocolNo].Init (&ImageHandle);

-      if (EFI_ERROR (Status)) {

-        ASSERT (FALSE);

-        return Status;

+  for (ProtocolIndex = 1; ProtocolIndex < ARRAY_SIZE (Protocols);

+       ProtocolIndex++) {

+    for (Index = 0; Index < NumProtocols; Index++) {

+      if (Protocols[ProtocolIndex].Id == SupportedList[Index]) {

+        Status = Protocols[ProtocolIndex].InitFn (&ImageHandle);

+        if (EFI_ERROR (Status)) {

+          ASSERT_EFI_ERROR (Status);

+          return Status;

+        }

+        break;

       }

     }

   }

diff --git a/ArmPkg/Drivers/ArmScmiDxe/ScmiDxe.h b/ArmPkg/Drivers/ArmScmiDxe/ScmiDxe.h
index 29cdde1..222e54f 100644
--- a/ArmPkg/Drivers/ArmScmiDxe/ScmiDxe.h
+++ b/ArmPkg/Drivers/ArmScmiDxe/ScmiDxe.h
@@ -17,8 +17,9 @@
 #ifndef SCMI_DXE_H_

 #define SCMI_DXE_H_

 

+#include "ScmiPrivate.h"

+

 #define MAX_PROTOCOLS        6

-#define PROTOCOL_ID_MASK     0xF

 #define MAX_VENDOR_LEN       SCMI_MAX_STR_LEN

 

 /** Pointer to protocol initialization function.

@@ -35,7 +36,8 @@ EFI_STATUS
   );

 

 typedef struct {

-  SCMI_PROTOCOL_INIT_FXN Init;

-} SCMI_PROTOCOL_INIT_TABLE;

+  SCMI_PROTOCOL_ID Id;            // Protocol Id.

+  SCMI_PROTOCOL_INIT_FXN InitFn;  // Protocol init function.

+} SCMI_PROTOCOL_ENTRY;

 

 #endif /* SCMI_DXE_H_ */