• System wide cache flush

    M. Elsayed Badawy
    M. Elsayed Badawy

    Hello,

    I'm working with i.MX8DX (Dual Core CortexA35 + CortexM4) with the following simplified caching system:

    My need is to flush a cached memory area to RAM in order to be viewed by the M4 core, unfortunately this area maybe cached by Core 0 and…

    • Answered
    • 26 days ago
    • Processors
    • Cortex-A / A-Profile forum
  • io coherency and shareability

    dedoz
    dedoz

    Hi,

    I have been reading about io coherency and the inner/outer shareability (SH bits in PTE). I kind of understand the concept of both but need help to connect the 2 concepts together. Lets assume a platform with (runs only one OS):

    - CCI-400
    - A53 Cluster…

    • 1 month ago
    • Processors
    • Cortex-A / A-Profile forum
  • What is difference between DCCIMVAC and DCIMVAC?

    Austin0101
    Austin0101

    The DCIMVAC represents a cache invalidate work. But one specific remark is that it will clean the data if the data is dirty before invalidation. Refer to followings

    /******************************************************/

    6.2.4 Data cache maintenance…

    • 1 month ago
    • Processors
    • Cortex-A / A-Profile forum
  • How to flush write buffer when memory attribute is normal_nc

    bamvor_china
    bamvor_china

    Hi,

    I am working on access pcie bar in armv8-a cpu(cortex-A5x) powered soc. Right now, I encounter an issue about (maybe) coherent issue.

    When I write data(4 bytes aligned) to pcie bar with ioremap_wc, there is some incorrect data. And it is correct…

    • Answered
    • 5 months ago
    • Processors
    • Cortex-A / A-Profile forum
  • Cache Coherence

    Rohan
    Rohan

    Hi ,

       I am working on ARM Multiprocessor. The Following is scenario for Cache coherency . Please let me know if it is valid.

       1. Bring Core 1 out of reset.

       2. Bring Core 2 out of reset.

       3. Invalidate Core 2 data cache…

    • Answered
    • over 3 years ago
    • Processors
    • Cortex-A / A-Profile forum
  • MOESI state encoding of Cortex-A7

    Isa
    Isa

    Hi,

    I am looking at Cortex-A7 TRM, In "Direct Access to Internal Memory"

    we can see several information regarding a cache line. Those are:

    1. Current data in cache

    2. its 4-bit MOESI state,

    3. Outer Memory Attribute

    4. its tag

    5. NS State.

    However…

    • Answered
    • over 3 years ago
    • Processors
    • Cortex-A / A-Profile forum
  • Cache cleaning and invalidating in ARM Cortex-A

    Manyam
    Manyam

    Cleaning or invalidating the L1 cache and L2 cache will not be a single atomic operation. A core might therefore perform cache maintenance on a particular address in both L1 and L2 caches only as two discrete steps. If another core were to access the…

    • Answered
    • over 5 years ago
    • Processors
    • Cortex-A / A-Profile forum
  • Why A9 is multicore by A8 doesn't

    techguyz
    techguyz

    Hi Experts,

    Which factor in processor decides whether it can be used in multi-core or not ?

    Like as per my understanding A8 is used in single core whereas A9 is used in multi core. So which distinctive feature in A9 favors the multi core application ?

    • Answered
    • over 5 years ago
    • Processors
    • Cortex-A / A-Profile forum
  • General Feature of Cortex processors on cache coherency

    techguyz
    techguyz

    Hi Experts,

    Is there any general feature available in the cortex processors to realize the cache lines by DMA through AXI ?

    I found some features like CCI module available to provide this feature in multi-core environment. Other than that, is it possible…

    • Answered
    • over 5 years ago
    • Processors
    • Cortex-A / A-Profile forum
  • VMSAv8-64 and spinlock

    Ciro Donnarumma
    Ciro Donnarumma

    Hi,

    I'm trying to implement a spin-lock to synchronize the execution of all cores Cortex-A53 on my Xilinx-ZCU102 board, but I have some issues maybe due to a wrong configuration of the VMSA and cache coherence.

    I'm writing bare-metal code, without…

    • Answered
    • over 1 year ago
    • Processors
    • Cortex-A / A-Profile forum
  • shareability attribute for armv8 cortex a-53

    MarekBykowski
    MarekBykowski

    Hi,

    I have a system with a multiple quad core clusters with Cortex A-53 and the CCN-512. L1 through L2 are integrated caches where L3 is an outer cache in 8xHN-F of the CCN512.

    My question is how should I interpret the shareability domain: inner, outer…

    • Answered
    • over 2 years ago
    • Processors
    • Cortex-A / A-Profile forum
  • ARM cortex R5 Performance is decreased by 20% after enabling Cache coherence

    Sandeep Bobba
    Sandeep Bobba

    Currently working on Xilinx Zynq US+ soc where R5(2 cores in lock step) and A53 (4 cores) , PL and GPU are mounted onto a single chip.

    so far we were using the concept of software based cache coherency mechanism to communicate between R5 and A53 worlds…

    • Answered
    • over 1 year ago
    • Processors
    • Cortex-R / R-Profile forum
  • ARMv7-A: Cache maintenance operation by VA, performance

    Niklas
    Niklas

    Hi,

    according to this talk, cache maintenance should always be performed by VA and not by set/way except during boot or shutdown. However, invalidating/cleaning a block of data by VA requires a loop to run over the entire memory block (in steps equal…

    • Answered
    • over 1 year ago
    • Processors
    • Cortex-A / A-Profile forum
  • Extended System Coherency - Part 3 – Increasing Performance and Introducing CoreLink CCI-500

    Neil Parris
    Neil Parris

    Chinese Version 中文版: 扩展系统一致性 - 第 3 部分 - 性能提升和 CoreLink CCI-500 简介

    This week we announced the launch of a new suite of IP designed to enhance the premium mobile experience. A central part of this suite is the ARM CoreLink CCI-500 Cache Coherent Inter…

    • over 5 years ago
    • Processors
    • Processors blog
  • Extended System Coherency: Part 2 - Implementation, big.LITTLE, GPU Compute and Enterprise

    Neil Parris
    Neil Parris

    Chinese Version中文版:扩展系统一致性 - 第 2 部分 - 实施、big.LITTLE、GPU 计算和企业级应用

    This is the second part of a series of blogs about hardware coherency. In the first blog I introduced the fundamentals of cache coherency. This part talks about the implementation of hardware…

    • over 6 years ago
    • Processors
    • Processors blog
  • Exploring How Cache Coherency Accelerates Heterogeneous Compute

    Neil Parris
    Neil Parris

    Cache Coherency and Shared Virtual Memory

    The Heterogeneous System Architecture (HSA) Foundation is a not-for profit consortium for SoC IP vendors, OEMs, academia, SoC vendors, OSVs and ISVs whose goal is to make it easier for software developers to…

    • over 4 years ago
    • Processors
    • Processors blog
  • Extended System Coherency: Part 1 - Cache Coherency Fundamentals

    Neil Parris
    Neil Parris

    Chinese Version 中文版:扩展系统一致性 - 第 1 部分 - 缓存一致性基本信息

    Introduction

    The theme of TechCon 2013 was “Where intelligence connects” and in many ways hardware system coherency is an important part of connecting the intelligence of an SoC. This year I presented…

    • over 6 years ago
    • Processors
    • Processors blog
  • Why linux set memory as inner shareable in multi-cluster ARMv8 cores?

    thomas_cp
    thomas_cp

    Hi, 

    I have board with two clusters, one has 4*A57 cores, and the other has 4*A53 cores.

    The A57 cluster has its own L1 and L2 cache, A53 cluster also has its own L1 and L2 cache. Between the clusters there is a CCI.

    There is no L3 cache. So the memory…

    • over 2 years ago
    • Processors
    • Cortex-A / A-Profile forum
  • Is Cache Stashing introduced in DynamIQ similar to IO coherency?

    kangz
    kangz

     IO coherency also allows device to access coherent memory space. The only difference I noticed is that cache stashing connects device directly with cluster, however, IO coherency transactions need to go through system interconnect.

    • over 2 years ago
    • Processors
    • Cortex-A / A-Profile forum
  • Cache and store buffer maintenance in cortex-a8!

    Hamed
    Hamed

    Dear All,

    Technical data sheets for the ARM7500FE  and ARM7100 say that:

    "In the ARM Processor the cache will be searched regardless of the state of the C bit, only reads that miss the cache will be affected."

    Now the question is that whether…

    • Answered
    • over 5 years ago
    • Processors
    • Cortex-A / A-Profile forum
  • Cache maintenance and DMA

    Michael Pulice
    Michael Pulice

    Greetings ARM community,

    I have been tasked with cache maintenance.  The necessity popped up because of DMA issues on USB.

    As a quick (not perm solution) I used the invalidate all routine.  While obviously not nominal in anyway

    it does allow me…

    • Answered
    • over 6 years ago
    • Processors
    • Cortex-A / A-Profile forum
  • What's the Cortex-A12 Main Bus Interface?

    Jin-Hwi Jun
    Jin-Hwi Jun

    Does Cortex-A12 not supprt AMBA4 ACE protocol?

    The figure and description of the Cortex-A12 product page(http://www.arm.com/products/processors/cortex-a/cortex-a12-processor.php) shows as if it only supports "AMBA4 AXI Bus" is available bus interface…

    • Answered
    • over 6 years ago
    • Processors
    • Cortex-A / A-Profile forum
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