Arm A-Profile Architecture Developments 2020

Find the Latest SoC Solutions
for... Automotive... IoT... Security... Audio... Video

arm Blogs - Martin Weidmann, Arm

community.arm.com, Sept. 21, 2020 – 

Working with its architecture licensees and ecosystem partners, Arm continues to evolve its architecture, developing new functionality to meet the needs of both new and existing markets.

This blog discusses some of the key additions to the A-profile architecture in 2020.

This blog also introduces two new additions to the Future Architecture Technologies program, which provides advanced information on unreleased versions of the architecture.

Full Instruction Set and System Register information will be available via our technical webpages. The complete Armv8-A Architecture Reference Manual (ArmARM), documenting the 2020 extensions and earlier functionality, is due for release in early 2021. XML releases will be available soon and we will link to those when available.

Details of previous updates to the A-profile architecture are available here: 2014, 2015, 2016, 2017, 2018 and 2019.

Enhanced support for device – hot-unplug

As part of the 2020 extensions, Arm is adding the ability to identify devices which can be subject to long delays. TLB invalidate (TLBI) operations and barriers can also be annotated with this attribute.

Technologies such as PCIe allow for devices to be hot-unplugged. This can occur even when there are outstanding requests to the device. When a device is removed, the PCIe root complex will respond with a default response after a timeout period, which is typically in the order of 50ms.

Some impact on the software directly interacting with the removed device is expected. However, we want to minimize the impact on other, unrelated tasks. Consider the following example:

click here to read more...

 Back