On Sat, Dec 22, 2018 at 7:09 AM Daniel F. Dickinson
<cshored@xxxxxxxxxxxxx> wrote:
>
> ath9k_of_init() function[0] was initially written on the assumption that
> if someone had an explicit ath9k OF node that "there must be something
> wrong, why would someone add an OF node if everything is fine"[1]
> (Quoting Martin Blumenstingl <martin.blumenstingl@xxxxxxxxxxxxxx>)
>
> "it turns out it's not that simple. with your requirements I'm now aware
> of two use-cases where the current code in ath9k_of_init() doesn't work
> without modifications"[1]
>
> The "your requirements" Martin speaks of is the result of the fact that I
> have a device (PowerCloud Systems CR5000) has some kind of default - not
> unique mac address - set and requires to set the correct MAC address via
> mac-address devicetree property, however:
>
> "some cards come with a physical EEPROM chip [or OTP] so "qca,no-eeprom"
> should not be set (your use-case). in this case AH_USE_EEPROM should be
> set (which is the default when there is no OF node)"[1]
>
> The other use case is:
>
> the firmware on some PowerMac G5 seems to add a OF node for the ath9k
> card automatically. depending on the EEPROM on the card AH_NO_EEP_SWAP
> should be unset (which is the default when there is no OF node). see [3]
>
> After this patch to ath9k_of_init() the new behavior will be:
>
> if there's no OF node then everything is the same as before
> if there's an empty OF node then ath9k will use the hardware EEPROM
> (before ath9k would fail to initialize because no EEPROM data was
> provided by userspace)
> if there's an OF node with only a MAC address then ath9k will use
> the MAC address and the hardware EEPROM (see the case above)
> with "qca,no-eeprom" EEPROM data from userspace will be requested.
> the behavior here will not change
> [1]
>
> Martin provides additional background on EEPROM swapping[1].
>
> Thanks to Christian Lamparter <chunkeey@xxxxxxxxx> for all his help on
> troubleshooting this issue and the basis for this patch.
>
> Fixes: 138b41253d9c ("ath9k: parse the device configuration from an OF node")
>
> [0]https://elixir.bootlin.com/linux/v4.20-rc7/source/drivers/net/wireless/ath/ath9k/init.c#L615
> [1]https://github.com/openwrt/openwrt/pull/1645#issuecomment-448027058
> [2]https://github.com/openwrt/openwrt/pull/1613
> [3]https://patchwork.kernel.org/patch/10241731/
+Cc Bas Vermeulen: can you please try Daniel's patch on your PowerMac
G5? I hope that this replaces your "endian_check" module parameter!
> Signed-off-by: Daniel F. Dickinson <cshored@xxxxxxxxxxxxx>
Reviewed-by: Martin Blumenstingl <martin.blumenstingl@xxxxxxxxxxxxxx>
(to me the description makes sense, but that said: I contributed some
of the description)
as well as:
Tested-by: Martin Blumenstingl <martin.blumenstingl@xxxxxxxxxxxxxx>
(on my BT HomeHub 5A - which sets qca,no-eeprom - using OpenWrt, which
is currently running backports v4.19.7)
Martin
