[PATCH 00/20] staging: brcm80211: 7th reaction for mainline patch #2

Arend Van Spriel arend at broadcom.com
Thu Sep 22 09:04:45 UTC 2011


> From: linux-wireless-owner at vger.kernel.org [mailto:linux-wireless-
> owner at vger.kernel.org] On Behalf Of Hauke Mehrtens
> Sent: donderdag 22 september 2011 8:47
> To: Brett Rudley
> Cc: Rafał Miłecki; Greg KH; John W. Linville; Franky (Zhenhui) Lin;
> gregkh at suse.de; devel at linuxdriverproject.org; linux-
> wireless at vger.kernel.org
> Subject: Re: [PATCH 00/20] staging: brcm80211: 7th reaction for
> mainline patch #2
> 
> On 09/22/2011 12:12 AM, Brett Rudley wrote:
> >>> Our original plan was to remain a separate driver from b43. We were
> >> aware of it and all the good work that had been done to create it
> and we
> >> had no intention of interfering with it.  At that point there had
> not
> >> been very much recent movement in b43 and it did not support any of
> our
> >> AXI based chips.  We figured that ssb vs AXI was a good dividing
> line and
> >> there would be no conflict, and there wasn't initially.
> >>
> >> The first obvious problem is that there are SSB and BCMA (aka AXI)
> >> cards using N-PHY. That resulted in PHY code duplication between b43
> >> and brcmsmac. And since we already supported N-PHY in b43, adding
> bcma
> >> support automatically gave us BCM43224 and BCM43225 support. That of
> >> course means duplicated supported for the same hardware.
> >
> > Agree, when you created bcma, it did duplicate HW support already in
> brcmsmac.  Why didn't you address that then?
> 
> bcma is not only used to support the bus on a pci based wireless cards
> it now also contains support for SoCs like the BCM4718. There it
> provides a common interface to the hardware for the wireless so that
> there were no changes in b43 needed to get the wireless core running on
> this SoC. It also provides some parts needed to get the SoC boot in
> Linux and so on, some parts are related to the MIPS CPU and not related
> to the wireless core, so it makes sense to put that into an own module.
> 
> Hauke

You are right. BCMA in itself only duplicates part of what is in brcmsmac
and its existence provides good functional separation. That is why we fully
intend to have brcmsmac use bcma. Brett meant that the duplication started
when b43 was getting patches for bcma support.

Rafał indicated that b43 team was working on n-phy support when we released
the brcm80211 driver (aka brcmsmac). No one indicated this before so I can
only assume that b43 decided to move on building bcma and have no interest
in brcmsmac moving in the linux tree.

Gr. AvS


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