Restructured the EC spec to include HID

docs/src/SUMMARY.md

@@ -5,18 +5,22 @@
 - [Development](development.md)
   - [Supply-chain auditing](supply-chain.md)
 - [Specifications](specs/specifications.md)
-  - [Embedded Controller Interface](specs/ec_interface/ec_interface.md)
+  - [Embedded Controller Interface](specs/ec_interface/README.md)
     - [EC SoC Interface](specs/ec_interface/ec-soc-interface.md)
-    - [Legacy EC Interface](specs/ec_interface/legacy-ec-interface.md)
-    - [Secure EC Services Overview](specs/ec_interface/secure-ec-services-overview.md)
-    - [EC Firmware Management](specs/ec_interface/ec-firmware-management.md)
-    - [EC Power Service](specs/ec_interface/ec-power-service.md)
-    - [Battery Service](specs/ec_interface/battery-service.md)
-    - [Thermal Service](specs/ec_interface/thermal-service.md)
-    - [UCSI Interface](specs/ec_interface/ucsi-interface.md)
-    - [EC Input Management](specs/ec_interface/ec-input-management.md)
-    - [EC Time Alarm Service](specs/ec_interface/ec-time-alarm-service.md)
-    - [EC Debug Service](specs/ec_interface/ec-debug-service.md)
-    - [EC Manufacturing Service](specs/ec_interface/ec-manufacturing-service.md)
-    - [EC OEM Service](specs/ec_interface/ec-oem-service.md)
-    - [Sample System Implementation](specs/ec_interface/sample-system-implementation.md)
+    - [Legacy EC Interface](specs/ec_interface/legacy/README.md)
+    - [FF-A EC Interface](specs/ec_interface/ffa/README.md)
+      - [EC Firmware Management](specs/ec_interface/ffa/management.md)
+      - [EC Power Service](specs/ec_interface/ffa/power.md)
+      - [Battery Service](specs/ec_interface/ffa/battery.md)
+      - [Thermal Service](specs/ec_interface/ffa/thermal.md)
+      - [UCSI Interface](specs/ec_interface/ffa/ucsi.md)
+      - [EC Input Management](specs/ec_interface/ffa/input.md)
+      - [EC Time Alarm Service](specs/ec_interface/ffa/time-alarm.md)
+      - [EC Debug Service](specs/ec_interface/ffa/debug.md)
+      - [EC Manufacturing Service](specs/ec_interface/ffa/manufacturing.md)
+      - [EC OEM Service](specs/ec_interface/ffa/oem.md)
+      - [Sample System Implementation](specs/ec_interface/ffa/acpi-sample.md)
+    - [HID EC Interface](specs/ec_interface/hid/README.md)
+      - [HID Time and Alarm](specs/ec_interface/hid/HUTRR120-SystemWakeTimerAndRTC.md)
+      - [HID Battery](specs/ec_interface/hid/HUTRR-DRAFT-Battery.md)
+    - [eSPI PCC Specification](specs/ec_interface/espi/espi_pcc_draft.md)

docs/src/specs/ec_interface/README.md

@@ -0,0 +1,147 @@
+# Embedded Controller Interface Specification
+
+The Embedded Controller (EC) Interface Specification describes a base set of requirements for interfacing with core
+Windows features.
+
+It covers the following areas:
+- Firmware Management
+- Battery
+- Time and Alarm
+- UCSI
+- Thermal
+- Power
+- Input Devices
+- Customization
+
+## Protocols and Stacks
+
+There are 3 ways to communicate with the EC:
+
+- ACPI specification for Legacy EC controller (eSPI) based interface on x86 devices, directly accessed through OperationRegion in ACPI
+- ACPI through FFA driver and in secure world an SV or OEM customer driver to communicate with the EC on ARM devices
+- Directly through HID class driver for bus based devices, I2C, I3C and eSPI
+
+This specification is organized accordingly and you can find the details for each protocol in the sub folder.
+
+[Legacy EC Interface](legacy/README.md)
+
+[FFA EC Interface](ffa/README.md)
+
+[HID EC Interface](hid/README.md)
+
+
+## Transports
+
+While other transports can be wired up to work with OEM or SV drivers we are focused on supporting I2C, I3C and eSPI natively both through direct ACPI access and the HID stacks.
+
+Today there is partial support for I2C and eSPI in ACPI and support for I2C and I3C on HID. To support eSPI natively work is being done to better standardize eSPI based on PCC specification.
+
+The following is a visual of the driver stacks planned to interface with the EC from the OS.
+
+## CPU-to-Embedded-Controller Architecture
+
+```mermaid
+flowchart TB
+    subgraph CPU["CPU / PC"]
+        direction LR
+
+        subgraph NSW["Non-Secure World"]
+            direction TB
+
+            subgraph STACK["Top-Level Stack"]
+                direction LR
+                INPUT["Input"]
+                BATTERY["Battery"]
+                TAD["TAD"]
+                MPTF["MPTF"]
+                OEM["OEM"]
+            end
+
+            subgraph HID_DRIVERS["HID Class Drivers"]
+                direction LR
+                INPUT_HID["Input HID Driver"]
+                BATTERY_HID["Battery HID Driver"]
+                TAD_HID["TAD HID Driver"]
+                MPTF_HID["MPTF HID Driver"]
+                OEM_HID["OEM HID Driver"]
+            end
+
+            INPUT --> INPUT_HID
+            BATTERY --> BATTERY_HID
+            TAD --> TAD_HID
+            MPTF --> MPTF_HID
+            OEM --> OEM_HID
+
+            subgraph OS_DRIVERS["OS Driver Layer"]
+                direction LR
+                HIDCLASS["HIDClass Driver"]
+                ACPI["ACPI Driver"]
+            end
+
+            INPUT_HID --> HIDCLASS
+            BATTERY_HID --> HIDCLASS
+            TAD_HID --> HIDCLASS
+            MPTF_HID --> HIDCLASS
+            OEM_HID --> HIDCLASS
+
+            subgraph HID_SUPPORT["HID Transport Support"]
+                direction LR
+                HIDSPBCX["HIDSpbCx"]
+                HIDI3C["HIDI3C"]
+                HIDESPI["HIDeSPI"]
+            end
+
+            HIDCLASS --> HIDSPBCX
+            HIDCLASS --> HIDI3C
+            HIDCLASS --> HIDESPI
+
+            I2C["I2C Transport"]
+            I3C["I3C Transport"]
+            ESPI["eSPI Transport"]
+
+            HIDSPBCX --> I2C
+            HIDI3C --> I3C
+            HIDESPI --> ESPI
+
+            FFA["FF-A"]
+            I2CI3C["I2C/I3C"]
+            ESPIA["ESPI"]
+            ACPI --> FFA
+            ACPI --> I2CI3C
+            ACPI --> ESPIA
+        end
+
+        subgraph SW["Secure World"]
+            direction TB
+            HAFNIUM["Hafnium"]
+            ECSP["EC SP"]
+            CUSTOM["Custom Transport Driver"]
+
+            HAFNIUM --> ECSP
+            ECSP --> CUSTOM
+        end
+
+        FFA --> HAFNIUM
+    end
+
+    subgraph EC["Embedded Controller"]
+        direction TB
+        EC_IF["EC Transport Interfaces"]
+        EC_FW["EC Firmware / Services"]
+        EC_IF --> EC_FW
+    end
+
+    I2C -->|I2C| EC_IF
+    I3C -->|I3C| EC_IF
+    ESPI -->|eSPI| EC_IF
+    ESPIA -->|eSPI| EC_IF
+    I2CI3C --> |ACPI| EC_IF
+    CUSTOM -->|Custom secure transport| EC_IF
+
+    classDef nonsecure fill:#dbeafe,stroke:#2563eb,color:#111827;
+    classDef secure fill:#fef3c7,stroke:#d97706,color:#111827;
+    classDef controller fill:#dcfce7,stroke:#16a34a,color:#111827;
+    class INPUT,BATTERY,TAD,MPTF,OEM,INPUT_HID,BATTERY_HID,TAD_HID,MPTF_HID,OEM_HID,HIDCLASS,ACPI,HIDSPBCX,HIDI3C,HIDESPI,I2C,I3C,ESPI,FFA nonsecure;
+    class HAFNIUM,ECSP,CUSTOM secure;
+    class EC_IF,EC_FW controller;
+```

docs/src/specs/ec_interface/ec-soc-interface.md

@@ -19,4 +19,5 @@ work towards a more robust solution that will handle routing, larger
 packets and security in a common way across OS’s and across SV
 architectures. 
 
-![EC connections to apps](media/odp_arch.png)
+See the [CPU-to-Embedded-Controller Architecture](README.md#cpu-to-embedded-controller-architecture) for the supported
+software stacks and transport paths.