[ericfontaine]

"There is no firmware at all on the ath9k wifi chipsets."

No, there is firmware inside the wifi. Just looking at a specific chip ath9k wifi device: https://www.qca.qualcomm.com/wp-content/uploads/2013/11/AR94... I see it has a "32-bit Tensilica Xtensa CPU" and this CPU is running some proprietary firmware on the embedded Code ROM. Although this firmware cannot be updated, is completely isolated from the main x86 CPU in my libreboot X60s, can't directly access any data outside of the physical miniPCI board, and only interfaces to the rest of computer via open-source x86 driver code on the main CPU, this embedded ROM code controlling the embedded RISC processor is however still proprietary firmware. This is the same deal with the microcontrollers inside the HDD/SDD and graphics chipset, which all have proprietary embedded firmware which is interfaced with by the opensource x86 drivers. Firmware != driver.

[fchmmr]

The PDF that you linked to is talking about AR9462. Libreboot machines typically use chips with the AR9285 chipset.

[ericfontaine]

Ok, I simply linked to that as an example of a device that can interface with the free ath9k driver. Looking at https://www.qca.qualcomm.com/wp-content/uploads/2013/11/AR92... I can't really see any closer detail inside of the black boxes labeled "Baseband PHY and Wireless MAC" and "Host Interface" but I can make a very educated guess that they are running some very simple RISC and/or DSP with code off a ROM responsible for performing all the non-analog functions necessary for wireless media access control (e.g. error recovery, finding free channels, Rx/Tx buffering) and for interfacing with PCIe bus, outside of functions that handle higher level of the networking stack that are more practically implemented in the ath9k driver code running in the x86 cpu.