Platform/ARM/VExpressPkg: support firmware update feature.

[LeviYeoReum]

Introduction

The Firmware Update Feature is based on
[Platform Security Firmware Update for the A-profile Specification 1.0][1] specification.
To update firmware, Firmware Update Feature uses FmpDevicePkg framework
for the firmware to be updated via capsule update framework.

Updates firmware with Capsule update framework in Arm with following steps:

• Deliver firmware image via UpdateCapsule().
• firmware image delivered to StandaloneMm via MmCommunication or FF-A.
• StandaloneMm which is UpdateAgent write new image in firmware update storage
  according to PSA specification.
• To apply updated firmware, Reset.

This is slight different from other architecture which using
coalescing update firmware with following steps:

• Deliver the firmware image via UpdateCapsule().
• Save the firmware image in the variable storage.
• Warm Reset, and In PEI phase coalesce the firmware image scattered in physical memory.
• Before EndofDxe, update the firmware by calling ProcessCapsules()
• To apply the updated firmware, Reset.
  for preventing arbitrary access to firmware storage device locked after EndofDxe phase.

It's the reason Arm doesn't supports coalescing way because
- According to platform UEFI doesn't run in ROM but
it loaded to memory by TF-A
- According to platform, it can skip PEICORE (See EDK2_SKIP_PEICORE)
- Arm doesn't need to lock the firmware storage device because
it's completely isolated in StandaloneMm (at S-EL0).
Therefore, operating system, uefi or any other software components running in
normal world cannot access isolated firmware storage.

By doing so, it can remove WarmReset for unlocking device and support runtime
firmware update in the future.

This implementation is written for platforms where firmware storage's layout
(typical platform is Base FVP platform):

   +----------------------+
    |      GPT-HEADER      |
    +----------------------+
    |    FIP_A (bank0)     |
    +----------------------+
    |    FIP_B (bank1)     |
    +----------------------+
    |    FWU-Metadata      |
    +----------------------+
    |  Bkup-FWU-Metadata   |
    +----------------------+

and uses FwsGptSystemFipLib used to access above firmware storage.

Overview

Here is an overview of Firmware Update Feature.

    UEFI (Normal world)          |        StandaloneMm (Secure world)              
---------------------------------|--------------------------------------           
                                 |                             +-------+           
                                 |                    ---------|  Fws  |                                                                                                                                                                                                            
                                 |                    |        +-------+           
+------------------+             |                    |       (Gpt parted)         
|   FmpDevicePkg   |             |  Read /Write Image |                            
+------------------+             |                    |                            
  |                              |        +-------------------+                    
  |  SetTheImage and etc         |        |  FwsPlatformLib   |                    
  |  progress via FmpDeviceLib   |        +-------------------+                    
  |                              |                  |                              
  |                              |  Parsing Request | Access Fws via               
  |                              |                  | FwsPlatformLib               
  |                              |                  |                              
  |                              |                  |                              
  -> +---------------------+   PSA ABI (FF-A)    +-------------------+             
     |  FmpDevicePsaFwuLib |<------------------> |     FwuSmm.c      |             
     |   (FmpDeviceLib)    |   PSA Error code    +-------------------+             
     +---------------------+     |                                                 
                                                                                   

When UEFI calls UpdateCapsule(), FmpDevicePkg->SetTheImage() is called.
Through FmpDeviceLib, FmpDevicePkg requests a firmware update to StandaloneMm
according to Firmware Store Update ABI defined in [PSA][1] spec via PsaFwuLib.
Then FwuStMm StandaloneMm driver parses requests from PsaFwuLib and access to firmware
storage via FwsPlatformLib which is platform specific library.

Patch Sequence

Patch #1 adds CapsuleUpdateRuntimePolicyLib for Arm platform.
Patch #2 adds related GUID used for firmware update
Patch #3 adds FmpDevicePkg.dsc for firwmare update
Patch #4-#6 implements FwsGptSystemFipLib
Patch #7 adds FwuDriver which is firmware update agent
Patch #8 - #12 enables firmware update feature in FVP RevC platform.

References

[1] https://developer.arm.com/documentation/den0118/latest/
[2] https://developer.arm.com/products/system-design/fixed-virtual-platforms