On Tuesday 22 November 2016 17:14:28 Michal Kazior wrote: > On 22 November 2016 at 16:31, Pali Rohár <pali.rohar@xxxxxxxxx> wrote: > > On Tuesday 22 November 2016 16:22:57 Michal Kazior wrote: > >> On 21 November 2016 at 16:51, Pali Rohár <pali.rohar@xxxxxxxxx> > >> wrote: > >> > On Friday 11 November 2016 18:20:50 Pali Rohár wrote: > >> >> 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. > > This isn't particularly a problem for ath9k/ath10k. > > Let me give you more background on ath10k. > > ath10k devices can come with caldata and macaddr stored in their > OTP/EEPROM. In that case a generic "template" board file is used. > Userspace doesn't need to do anything special. > > Some vendors however decide to use flash partition to store caldata. > In that case ath10k expects userspace to prepare > cal-$bus-$devname.bin files, each for a different radio (you can > have multiple radios on a system). > > Now translating this for wl1251 I would expect it should also use > something like wl1251-nvs-sdio-0x0001.bin for devices like N900 that > have caldata on flash partition (instead of the generic > wl1251-nvs.bin). I'm not sure if wl1251-nvs.bin is something > comparable to (the generic) board.bin ath10k has though. Maybe the > entire idea behind wl1251-nvs.bin is flawed as it's supposed to be > device specific and is oblivious to possibility of having multiple > wl1251 radios on one system (probably sane assumption from practical > standpoint but still). Basically nvs data are device specific, in ideal case they should be generated in factory by some calibration process (or so). > >> >> 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. > > Quoting modprobe.d manual: > > install modulename command... > > > > This command instructs modprobe to run your > > command instead of inserting the module in the > > kernel as normal. The command can be any shell > > command: this allows you to do any kind of > > complex processing you might wish. [...] I know. But this do not allow me to send mac address to kernel -- as kernel does not support such command yet (reason for my first question). > You can hook up a script that cooks up wl1251-nvs.bin (caldata, > macaddr) and then insmod the actual wl1251.ko module. Or you can just > cook up the nvs on first device boot and store it in /lib/firmware > (possibly overwriting the "generic" wl1251 from linux-firmware). This is what I would like to prevent -- overwriting (possible readonly) system files with some device specific. It is really bad idea! -- Pali Rohár pali.rohar@xxxxxxxxx
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