GICv3 LPI Interrupt Delivery Failure After Bootloader Transition The issue at hand involves a custom bootloader that loads an image from an NVMe device, utilizing LPI (Locality-specific Peripheral Interrupts) interrupts routed through the GICv3 ITS (Interrupt Translation Service). The bootloader successfully loads the next image into RAM and transfers control to it. However, the second…
ARM Cortex-M Process Stack: Purpose and Architectural Context The ARM Cortex-M series of processors, widely used in embedded systems, features a unique architectural element known as the process stack. This stack is distinct from the main stack and plays a critical role in the execution environment of the processor. To understand its purpose, we must…
ARM Cortex-A Multi-Core Boot Failure During Initialization The issue at hand involves a failure in booting multiple cores on an ARM Cortex-A processor using the Fixed Virtual Platform (FVP) and the boot-wrapper-aarch64 software. The system successfully boots when running with a single core, but fails when multiple cores are enabled. The primary observation is that…
Issue Overview: The Role and Necessity of DBIDRespOrd in ARM CHI Protocol The ARM Coherent Hub Interface (CHI) protocol is a critical component in modern ARM-based systems, enabling efficient communication between processors, caches, and memory controllers. Within this protocol, the DBIDResp and DBIDRespOrd transactions play pivotal roles in managing data flow and maintaining coherency. However,…
Issue Overview: Second Core Receives Only One PL Interrupt in AMP Configuration In a Zynq 7020 Cortex-A9 Asymmetric Multiprocessing (AMP) setup, where each core runs a separate FreeRTOS instance, a critical issue arises with the second core’s ability to handle interrupts from Programmable Logic (PL)-based IPs. The second core initializes correctly, waits for the first…