3.3. Power Management

• 3.3.1. Power Management Overview
• 3.3.2. CPUIdle
• 3.3.3. AM62L Standby Mode
  • 3.3.3.1. Overview
  • 3.3.3.2. Device Tree Configuration
    • 3.3.3.2.1. Idle states
    • 3.3.3.2.2. Power Domain Hierarchy
    • 3.3.3.2.3. Deep Standby Mode
      • 3.3.3.2.3.1. Critical Prerequisites
      • 3.3.3.2.3.2. How to Enable Deep Standby Mode
  • 3.3.3.3. Power Sequencing and Cluster Standby Entry/Exit
  • 3.3.3.4. Hardware Sequence Details
  • 3.3.3.5. Monitoring Standby Activity
  • 3.3.3.6. Difference from System Sleep Modes
  • 3.3.3.7. Platform-Specific Implementation Details
• 3.3.4. Low Power Modes
  • 3.3.4.1. Overview
  • 3.3.4.2. Power Off Mode
    • 3.3.4.2.1. RTC Only
  • 3.3.4.3. Suspend to RAM Mode
    • 3.3.4.3.1. Selecting the Suspend to RAM Entry Mechanism
    • 3.3.4.3.2. RTC + I/O + DDR
    • 3.3.4.3.3. DeepSleep
    • 3.3.4.3.4. DSS plus DeepSleep
      • 3.3.4.3.4.1. How It Works
      • 3.3.4.3.4.2. Entering DSS plus DeepSleep Mode
      • 3.3.4.3.4.3. Changing from Always-On Static Display to Active Dynamic Display
  • 3.3.4.4. Memory Usage
• 3.3.5. Suspend-to-Idle (S2Idle) and PSCI Integration
  • 3.3.5.1. Suspend-to-Idle (S2Idle) Overview
  • 3.3.5.2. PSCI as the Enabler
  • 3.3.5.3. OS Initiated (OSI) Mode
    • 3.3.5.3.1. Why OSI?
    • 3.3.5.3.2. OSI Sequence
  • 3.3.5.4. Understanding the Suspend Parameter
    • 3.3.5.4.1. Power State Parameter Encoding
    • 3.3.5.4.2. Standard Format
    • 3.3.5.4.3. Example: System Suspend (Standard Format)
  • 3.3.5.5. S2Idle versus DeepSleep (mem)
    • 3.3.5.5.1. Design Philosophy
    • 3.3.5.5.2. Key Differences
    • 3.3.5.5.3. Context loss considerations
  • 3.3.5.6. Components Involved in Mode Selection in S2Idle (OSI Mode)
    • 3.3.5.6.1. Idle State Definitions
    • 3.3.5.6.2. Power Domain Hierarchy in Device Tree
    • 3.3.5.6.3. QoS Latency Constraints
  • 3.3.5.7. How Mode Selection Works
    • 3.3.5.7.1. Step-by-step traversal
    • 3.3.5.7.2. Examples
  • 3.3.5.8. Controlling Mode Selection from Userspace
    • 3.3.5.8.1. Setting CPU wakeup latency constraints
• 3.3.6. Wakeup Sources
  • 3.3.6.1. Real-Time Clock (RTC)
  • 3.3.6.2. MCU/WKUP GPIO
  • 3.3.6.3. Main I/O Daisy Chain
    • 3.3.6.3.1. Main UART
    • 3.3.6.3.2. Main GPIO
  • 3.3.6.4. WKUP I/O Daisy Chain
    • 3.3.6.4.1. WKUP UART I/O Daisy Chain
  • 3.3.6.5. WKUP UART
  • 3.3.6.6. USB Wakeup methods
    • 3.3.6.6.1. Host Mode Wakeup Events
      • 3.3.6.6.1.1. Wakeup via a device connect event
      • 3.3.6.6.1.2. Wakeup via a device disconnect event
      • 3.3.6.6.1.3. Via Remote wakeup event
    • 3.3.6.6.2. Device Mode Wakeup Events
      • 3.3.6.6.2.1. Wakeup via connect event
  • 3.3.6.7. MCU IPC based Wakeup
  • 3.3.6.8. CAN I/O Daisy Chain
  • 3.3.6.9. RTC I/O
    • 3.3.6.9.1. RTC I/O Pins 0 and 1
    • 3.3.6.9.2. RTC I/O Pin 2
  • 3.3.6.10. Confirming the Wakeup event type
• 3.3.7. Debug Information
  • 3.3.7.1. Low Power Modes
    • 3.3.7.1.1. Overview
    • 3.3.7.1.2. Prerequisites
    • 3.3.7.1.3. Step 1: Enable Low Power Logs in Board Configuration
    • 3.3.7.1.4. Step 2: Remove I/O Isolation and Enable Logging in TF-A
    • 3.3.7.1.5. Generating logs and running the parser script
      • 3.3.7.1.5.1. Step 1: Prepare the EVM terminal
      • 3.3.7.1.5.2. Step 2: Set up the parser script on host
      • 3.3.7.1.5.3. Step 3: Run and capture logs
      • 3.3.7.1.5.4. Alternative: Direct terminal output
    • 3.3.7.1.6. Troubleshooting: Parser errors
    • 3.3.7.1.7. Interpreting the logs
    • 3.3.7.1.8. Additional information: Decoding driver failures during suspend
• 3.3.8. Upstream Status
  • 3.3.8.1. Pending Upstream Series
  • 3.3.8.2. Workarounds