ACK: [PATCH v2 0/2] [SRU] [B/master] UBUNTU: SAUCE: arm64: snapdragon: wcn36xx MAC

[Khaled Elmously]

On 2018-06-14 12:08:55 , Paolo Pisati wrote:
> BugLink: http://bugs.launchpad.net/bugs/1776491
> 
> Impact:
> 
> The wcn36xx driver in Xenial/linux-snapdragon had an ability to autogenerate its
> MAC address upon boot, or read it from a file (/lib/firmware/wlan/macaddr0). The
> linux-snapdragon kernel in Bionic doesn't have this feature.
> 
> While by itself not a bug (Xenial used a QCOM provided custom driver, while
> Bionic uses the upstream wcn36xx driver), it can be easily work-arounded by
> specifying the hw address in /etc/network/interfaces, or set using ifconfig on
> the
> command line, but it turned out to be a real problem on ubuntu core:
> 
> 1) upon boot, with no MAC address assigned, the wcn36xx assigns itself the
> dummy address "00:00:00:00:00" and that prevents the network interface from
> working at all, until a valid address is set
> 
> 2) the ubuntu core installer doesn't have any knowledge about this behaviour,
> it simply tries to bring up the interface and on failure, it marks it as
> 'not working'
> 
> On top of that, ubuntu core ships a small script in initramfs, that generates
> the
> /lib/firmware/wlan/macaddr0 file starting from the android boot serial,
> effectively generating a unique MAC address per board: clearly, without driver
> support, this ubuntu core feature doesn't work.
> 
> Fix:
> 
> Import back the MAC generation mechanism from Xenial: the pseudo random
> generation and the parsing of /lib/firmware/wlan/macaddr0 - see the attached
> patch.
> 
> How to test:
> 
> Unpon boot, if no /lib/firmware/wlan/macaddr0 is present, the kernel will print:
> 
> [ 10.612701] wcn36xx a204000.wcnss:smd-edge:wcnss:wifi: Direct firmware load for
> wlan/macaddr0 failed with error -2
> [ 10.612713] wcn36xx a204000.wcnss:smd-edge:wcnss:wifi: Failed (-2) to read
> macaddressfile wlan/macaddr0, using a random address instead
> 
> ubuntu at dragon410c:~$ ifconfig wlan0
> wlan0: flags=4098<BROADCAST,MULTICAST> mtu 1500
>         ether 00:0a:f5:d5:54:d7 txqueuelen 1000 (Ethernet)
>         RX packets 0 bytes 0 (0.0 B)
>         RX errors 0 dropped 0 overruns 0 frame 0
>         TX packets 0 bytes 0 (0.0 B)
>         TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
> 
> else, if /lib/firmware/wlan/macaddr0 is present, its content will be used to
> generate wlan0 MAC address:
> 
> ubuntu at dragon410c:~$ cat /lib/firmware/wlan/macaddr0
> fe:1a:19:77:d9:88
> 
> ubuntu at dragon410c:~$ ifconfig wlan0
> wlan0: flags=4098<BROADCAST,MULTICAST> mtu 1500
>         ether fe:1a:19:77:d9:88 txqueuelen 1000 (Ethernet)
>         RX packets 0 bytes 0 (0.0 B)
>         RX errors 0 dropped 0 overruns 0 frame 0
>         TX packets 0 bytes 0 (0.0 B)
>         TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
> 
> Regression potential:
> 
> Low - the patch is small and the code is wrapped in a Kconfig option
> (WCN36XX_SNAPDRAGON_HACKS) that only affects the linux-snapdragon flavour,
> leaving the generic kernel untouched.
> 
> 
> Paolo Pisati (2):
>   UBUNTU: SAUCE: wcn36xx: read MAC from file or randomly generate one
>   UBUNTU: [Config] arm64: snapdragon: WCN36XX_SNAPDRAGON_HACKS=y
> 
>  debian.master/config/amd64/config.common.amd64     |  1 +
>  debian.master/config/arm64/config.flavour.generic  |  1 +
>  .../config/arm64/config.flavour.snapdragon         |  1 +
>  debian.master/config/armhf/config.common.armhf     |  1 +
>  debian.master/config/i386/config.common.i386       |  1 +
>  debian.master/config/ppc64el/config.common.ppc64el |  1 +
>  drivers/net/wireless/ath/wcn36xx/Kconfig           |  9 +++++
>  drivers/net/wireless/ath/wcn36xx/main.c            | 38 +++++++++++++++++++++-
>  8 files changed, 52 insertions(+), 1 deletion(-)
> 
Acked-by: Khalid Elmously <khalid.elmously at canonical.com>