Hard Processor System Technical Reference Manual: Agilex™ 5 SoCs

ID 814346
Date 11/27/2024
Public
Document Table of Contents

4.3.6.3.5. Bypass Mode

The SMMU supports both global and context specific Bypass modes.

In global bypass mode, all incoming requests bypass address translation. Global bypass can be applied to both secure and non-secure requests independently.

Context specific bypass allows individual translation contexts to bypass address translation. Software controls this by configuring the Stream Table Entry appropriately.

SMMU_CR0.SMMUEN controls the translation through the Non-secure interface and behavior of transactions on Non-secure streams. When SMMU_S_IDR1.SECURE_IMPL == 1, (two secure states), SMMUEN controls transaction Secure streams and the SMMU might be translating Secure transactions, even if SMMUEN == 0.

When SMMU_S_CR0.SMMUEN == 0:

  • Incoming transactions with security state matching do not undergo translation and their behavior is controlled by the SMMU_S_GPBA register.
  • Configuration or translation structures are not accessed.
  • As translation does not occur for bypassing transactions, translation related events are not recorded.