How to access the CCA related operation

Peter Oh poh at
Mon Aug 24 10:31:01 PDT 2015

There is WMI_10_x_SET_CCA_PARAMS_CMDID which to enable adaptive CCA in
firmware supported since 10.2.4 and all the actual operations are done in
firmware with registers as Ben addressed.
But I'm not clear how much register doc or firmware doc are opened to public


-----Original Message-----
From: ath10k [mailto:ath10k-bounces at] On Behalf Of Ben
Sent: Monday, August 24, 2015 9:33 AM
To: Seowoo Jang; ath10k at
Subject: Re: How to access the CCA related operation

It is in firmware, and you cannot reliably poke it through the driver
read/write register API because each time the radio resets (channel change,
etc), it is liable to re-write the CCA registers back to default values.

There is a large list of registers with 'CCA' in the name, but I don't know
what they really mean, and I had hard time getting that info out of QCA.  If
you have any better luck, please post whatever you can share.


On 08/23/2015 11:21 PM, Seowoo Jang wrote:
> Hello,
> We are trying to evaluate our idea on 802.11ac protocol with Atheros 
> qca9880 / ath10k driver.
> We would like to be able to access/know the result of the CCA (clear 
> channel
> assessment) operation
> or the level of interference on the carrier when we need.
> We have dug into the driver files and concluded that the CCA related 
> values are likely in the firmware or on the registers of the hardware.
> And please correct us if we are thinking wrong.
> We would appreciate the help if someone can give us some starting 
> points, such as the address of the register that stores the carrier 
> sensing values (CCA values) or the result of it (whether the carrier 
> is busy or idle), to investigate.
> The chipset we are using is compex WLE900VX-7AA.
> We are currently using Ubuntu 14.04.03 with kernel version 4.1.5, but 
> we can use any versions of OS and kernel if they support 802.11ac 
> bandwidth.
> Thank you for help in advance.
> -------------------------------
> Seowoo Jang, Ph.D.
> Ubiquitous Network Laboratory
> EECS, Seoul National University
> CEL   +82-10-3723-3401
> E-mail swjang at
> -------------------------------
> _______________________________________________
> ath10k mailing list
> ath10k at

Ben Greear <greearb at>
Candela Technologies Inc

ath10k mailing list
ath10k at

More information about the ath10k mailing list