add Arm64 specific HPA documentation

Heterogeneous computing is an important feature for a typical
NFV scenario (Edge computing, Access networking).

This document list specific hardware features for Arm64.
Later, I will add more features in it.

Change-Id: I5db29dd3842eb80dd707c762d7847c08e5b74252
Signed-off-by: Bin Lu <bin.lu@arm.com>

diff --git a/docs/arm/hardware_platform_awareness.rst b/docs/arm/hardware_platform_awareness.rst
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+ARM64 Hardware Platform Awareness
+=================================
+
+This document describes Arm64 specific features for HPA
+
+
+1. ARM64 ELF hwcaps
+-------------------
+The majority of hwcaps are intended to indicate the presence of features
+which are described by architected ID registers inaccessible to
+userspace code at EL0. These hwcaps are defined in terms of ID register
+fields, and should be interpreted with reference to the definition of
+these fields in the ARM Architecture Reference Manual.
+
+HWCAP_FP
+    Floating-point.
+    Functionality implied by ID_AA64PFR0_EL1.FP == 0b0000.
+
+HWCAP_ASIMD
+    Advanced SIMD.
+    Functionality implied by ID_AA64PFR0_EL1.AdvSIMD == 0b0000.
+
+HWCAP_EVTSTRM
+    The generic timer is configured to generate events at a frequency of
+    approximately 100KHz.
+
+HWCAP_AES
+    Advanced Encryption Standard.
+    Functionality implied by ID_AA64ISAR1_EL1.AES == 0b0001.
+
+HWCAP_PMULL
+    Polynomial multiply long (vector)
+    Functionality implied by ID_AA64ISAR1_EL1.AES == 0b0010.
+
+HWCAP_SHA1
+    SHA1 hash update accelerator.
+    Functionality implied by ID_AA64ISAR0_EL1.SHA1 == 0b0001.
+
+HWCAP_SHA2
+    SHA2 hash update accelerator.
+    Functionality implied by ID_AA64ISAR0_EL1.SHA2 == 0b0001.
+
+HWCAP_CRC32
+    CRC32 instruction.
+    Functionality implied by ID_AA64ISAR0_EL1.CRC32 == 0b0001.
+
+HWCAP_ATOMICS
+    Atomics instruction.
+    Functionality implied by ID_AA64ISAR0_EL1.Atomic == 0b0010.
+
+HWCAP_FPHP
+    Instructions to convert between half-precision and single-precision, and between half-precision and double-precision.
+    Functionality implied by ID_AA64PFR0_EL1.FP == 0b0001.
+
+HWCAP_ASIMDHP
+    Indicates whether the Advanced SIMD and Floating-point extension supports half-precision floating-point conversion operations.
+    Functionality implied by ID_AA64PFR0_EL1.AdvSIMD == 0b0001.
+
+HWCAP_CPUID
+    EL0 access to certain ID registers is available, to the extent
+    described by Documentation/arm64/cpu-feature-registers.txt.
+    These ID registers may imply the availability of features.
+
+HWCAP_ASIMDRDM
+    Indicates whether Rounding Double Multiply (RDM) instructions are implemented for Advanced SIMD.
+    Functionality implied by ID_AA64ISAR0_EL1.RDM == 0b0001.
+
+HWCAP_JSCVT
+    ARMv8.3 adds support for a new instruction to perform conversion
+    from double precision floating point to integer  to match the
+    architected behaviour of the equivalent Javascript conversion.
+    Functionality implied by ID_AA64ISAR1_EL1.JSCVT == 0b0001.
+
+HWCAP_FCMA
+    ARM v8.3 adds support for new instructions to aid floating-point
+    multiplication and addition of complex numbers.
+    Functionality implied by ID_AA64ISAR1_EL1.FCMA == 0b0001.
+
+HWCAP_LRCPC
+    ARMv8.3 adds new instructions to support Release Consistent
+    processor consistent (RCpc) model, which is weaker than the
+    RCsc model.
+    Functionality implied by ID_AA64ISAR1_EL1.LRCPC == 0b0001.
+
+HWCAP_DCPOP
+    The ARMv8.2-DCPoP feature introduces persistent memory support to the
+    architecture, by defining a point of persistence in the memory
+    hierarchy, and a corresponding cache maintenance operation, DC CVAP.
+    Functionality implied by ID_AA64ISAR1_EL1.DPB == 0b0001.
+
+HWCAP_SHA3
+    Secure Hash Standard3 (SHA3)
+    Functionality implied by ID_AA64ISAR0_EL1.SHA3 == 0b0001.
+
+HWCAP_SM3
+    Commercial Cryptography Scheme.
+    Functionality implied by ID_AA64ISAR0_EL1.SM3 == 0b0001.
+
+HWCAP_SM4
+    Commercial Cryptography Scheme.
+    Functionality implied by ID_AA64ISAR0_EL1.SM4 == 0b0001.
+
+HWCAP_ASIMDDP
+    Performing dot product of 8bit elements in each 32bit element
+    of two vectors and accumulating the result into a third vector.
+    Functionality implied by ID_AA64ISAR0_EL1.DP == 0b0001.
+
+HWCAP_SHA512
+    Secure Hash Standard
+    Functionality implied by ID_AA64ISAR0_EL1.SHA2 == 0b0002.
+
+HWCAP_SVE
+    Scalable Vector Extension (SVE) is a vector extension for
+    AArch64 execution mode for the A64 instruction set of the Armv8 architecture.
+    Functionality implied by ID_AA64PFR0_EL1.SVE == 0b0001.
+
+2. ARM64 Memory Partitioning and Monitoring (MPAM)
+--------------------------------------------------
+Armv8.4-A adds a feature called Memory Partitioning and Monitoring (MPAM). This has several uses.
+Some system designs require running multiple applications or multiple virtual machines concurrently on a system
+where the memory system is shared and where the performance of some applications or some virtual machines must
+be only minimally affected by other applications or virtual machines. These scenarios are common in enterprise
+networking and server systems.
+This proposal addresses these scenarios with two approaches that work together under software control:
+- Memory/Cache system resource partitioning
+- Performance resource monitoring
+
+3. Arm Power State Coordination Interface (PSCI)
+------------------------------------------------
+PSCI has the following intended uses:
+- Provides a generic interface that supervisory software can use to
+manage power in the following situations:
+- Core idle management.
+- Dynamic addition of cores to and removal of cores from the
+system, often referred to as hotplug.
+- Secondary core boot.
+- Moving trusted OS context from one core to another.
+- System shutdown and reset.
+- Provides an interface that supervisory software can use in conjunction
+with Firmware Table (FDT and ACPI) descriptions to support the
+generalization of power management code.
+
+4. Arm TrustZone
+----------------
+Arm TrustZone technology provides system-wide hardware isolation for trusted software.
+The family of TrustZone technologies can be integrated into any Arm Cortex-A core,
+supporting high-performance applications processors, with TrustZone technology for Cortex-A processors.
+
+5. Arm CPU Info Detection
+-------------------------
+Computing resources should be collected by NFV COE, such as:
+- Arm specific:
+  CPU Part: indicates the primary part number.
+            For example:
+            0xD09      Cortex-A73 processor.
+
+  CPU Architecture: indicates the architecture code.
+           For example:
+           0xF Defined by CPUID scheme.
+
+  CPU Variant: indicates the variant number of the processor.
+            This is the major revision number n in the rn part of
+            the rnpn description of the product revision status.
+
+  CPU Implementer: indicates the implementer code.
+            For example:
+            0x41       ASCII character 'A' - implementer is ARM Limited.
+
+  CPU Revision: indicates the minor revision number of the processor.
+            This is the minor revision number n in the pn part of
+            the rnpn description of the product revision status.