MuRata WiFi Module with Marvell 88w8686

[Dan Williams]

On Tue, 2008-05-20 at 10:33 -0700, Tim Harvey wrote:
> Dan Williams wrote:
> > On Tue, 2008-05-20 at 13:48 +0800, claud_yu wrote:
> >   
> >> --- 08/5/16 (星期五)，Tim Harvey <tharvey at irobot.com> 寫道：
> >>
> >>     
> >>> 寄件者: Tim Harvey <tharvey at irobot.com>
> >>> 主旨: RE: MuRata WiFi Module with Marvell 88w8686
> >>> 收件者: claud_yu at yahoo.com.tw
> >>> 副本: libertas-dev at lists.infradead.org
> >>> 日期: 2008 5 16 星期五 上午 2:59
> >>> Claud,
> >>>
> >>> Thanks for your work here!  I've successfully gotten a
> >>> Zcomax XG-182M
> >>> (http://www.zcomax.com/embedded.htm#XG-182M) module based
> >>> on the 88W8686
> >>> working on an i.MX31 platform using the 8.73.7p3 fw using
> >>> your patches.
> >>> I still have a couple of questions.
> >>>
> >>> When I bring up the driver, I see some commands fail:
> >>>
> >>> libertas_sdio: Libertas SDIO driver
> >>> libertas_sdio: Copyright Pierre Ossman
> >>> HOTPLUG: firmware add
> >>> /usr/lib/hotplug/firmware/sd8686_helper.bin
> >>> HOTPLUG: firmware add /usr/lib/hotplug/firmware/sd8686.bin
> >>> libertas: 00:19:70:02:12:3c, fw 8.73.7p3, cap 0x00000303
> >>> libertas: PREP_CMD: command 0x00a3 failed: 2
> >>> libertas: PREP_CMD: command 0x00a3 failed: 2
> >>> libertas: eth1: Marvell WLAN 802.11 adapter
> >>>       
> >> I never send 0xa3 command to 88w8686 in my current driver . And I can't find any document about command 0xa3. The 0xa3 command (CMD_MESH_CONFIG) exist after 2.6.25 kernel. I didn't try to back port 2.6.25 to 2.6.22. The code I used is from main stream 2.6.24.
> >>     
> >
> > Anything "mesh" is OLPC firmware specific and thus won't be applicable
> > to any other chip besides the 8388 or firmware version.  If other chips
> > freak out when they get sent invalid commands, we need to whitelist the
> > 8388 or something.  But I doubt that sending the initial mesh check
> > would be causing these issues; the firmware is (hopefully) robust enough
> > to just return an error.
> >   
> So the OLPC 'software' is linux and uses the libertas driver?  I saw 
> that there is an effort to build GPL firmware for the 8388 but currently 
> the firmware is not GPL correct?

Yes; the original libertas bits committed to the Linux kernel around the
2.6.18 timeframe came from a Marvell reference driver that was
re-licensed to GPL and handed to OLPC.  Those of us from Red Hat working
on OLPC (Marcelo Tossati, Dave Woodhouse, and myself) cleaned that
driver up and pushed it upstream.

OLPC required mesh functionality, so Marvell contracted with CozyBit to
implement pre-802.11s mesh networking functionality in the firmware of
the 8388 device, which is what all the 'mesh' references in the libertas
driver refer to.  The mesh-enabled fullmac firmware is specific to OLPC
and the 8388 at this time.

A few people put some time into creating a FOSS firmware replacement for
the 8388 but AFAIK it hasn't gotten too far yet.

Dan

> The 'PREP_CMD: command 0x00a3 failed' doesn't cause an issue... I was 
> just surprised to see it
> 
> >   
> >>> The 0x00a3 cmd is CMD_MESH_CONFIG - I assume this is for
> >>> the 802.11s
> >>> like MESH that Cozybits added.  Am I correct in that this
> >>> support only
> >>> exists in the USB firmware and thats why I see the errors
> >>> when using an
> >>> SDIO module?
> >>>       
> >> You maybe right. That should depend on the firmware. I don't know that either.
> >>     
> >
> > Yes; but again I don't think it should affect the operation of any other
> > firmware version to just check once.  We should only be checking for
> > mesh once and then we should never be calling another mesh-related
> > command.
> >
> > Dan
> >
> >   
> >>> Regarding the patch you had to make to the Freescale MMC
> >>> driver
> >>> (drivers/mmc/core/mxc_mmc.c) to disable 4-bit SDIO mode -
> >>> are you
> >>> thinking that there is a bug with Freescales SDHC or is
> >>> there some issue
> >>> with the 88W8686 and/or the firmware here?  My
> >>> understanding is that the
> >>> 8686 should support 1-bit SDIO, 4-bit SDIO, and SPI - am I
> >>> wrong about
> >>> this?
> >>>       
> >> I don't know who is bad guy. But I know another 88W8686 module maker use the same configuration to make iMX31 and 88w8686 work together. 
> >> And their report show 4 bit mode have the same CRC error like my first implementation.
> >>
> >>
> >>     
> >>> Regarding the patch you had to make to libertas
> >>> (drivers/net/wireless/libertas/if_sdio.c) to force the io
> >>> chunk size to
> >>> be a multiple of the MX31 SDHC's block size - are you
> >>> thinking that this
> >>> is a bug/limitation of the MX31 SDHC?
> >>>       
> >> That depend some HW issue. Basically I want use DMA all the time.
> >> And DMA have more constraint the PIO ( address and size alignment). 
> >> That will be basic trade-off. 
> >>
> >> Claud Yu
> >>
> >>
> >>
> >>
> >>       ______________________________________________________________________________________________________
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> >>
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> >>     
> >
> >   
>