On Tuesday 22 November 2016 16:22:57 Michal Kazior wrote:

On 21 November 2016 at 16:51, Pali Rohár [off-list ref] wrote:

quoted

On Friday 11 November 2016 18:20:50 Pali Rohár wrote:

quoted

Hi! I will open discussion about mac address and calibration data for
wl1251 wireless chip again...

Problem: Mac address & calibration data for wl1251 chip on Nokia N900
are stored on second nand partition (mtd1) in special proprietary format
which is used only for Nokia N900 (probably on N8x0 and N9 too).
Wireless driver wl1251.ko cannot work without mac address and
calibration data.

Same problem applies to some ath9k/ath10k supported routers. Some even
carry mac address as implicit offset from ethernet mac address. As far
as I understand OpenWRT cooks cal blobs on first boot prior to loading
modules.

So... wl1251 on Nokia N900 is not alone and this problem is there for
more drivers and devices. Which means we should come up with some
generic solution.

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Absence of mac address cause that driver generates random mac address at
every kernel boot which has couple of problems (unstable identifier of
wireless device due to udev permanent storage rules; unpredictable
behaviour for dhcp mac address assignment, mac address filtering, ...).

Currently there is no way to set (permanent) mac address for network
interface from userspace. And it does not make sense to implement in
linux kernel large parser for proprietary format of second nand
partition where is mac address stored only for one device -- Nokia N900.

Driver wl1251.ko loads calibration data via request_firmware() for file
wl1251-nvs.bin. There are some "example" calibration file in linux-
firmware repository, but it is not suitable for normal usage as real
calibration data are per-device specific.

You could hook up a script that cooks up the cal/mac file via
modprobe's install hook, no?

Via modprobe hook I can either pass custom module parameter or call any
other system (shell) commands.

As wl1251.ko does not accept mac_address as module parameter, such
modprobe hook does not help -- as there is absolutely no way from
userspace to set or change (permanent) mac address.

-- 
Pali Rohár
pali.rohar@gmail.com