4.19-stable review patch. If anyone has any objections, please let me know.
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From: Daniel F. Dickinson cshored@thecshore.com
commit ce938231bd3b1d7af3cbd8836f084801090470e1 upstream.
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@googlemail.com)
"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@gmail.com for all his help on troubleshooting this issue and the basis for this patch.
[0]https://elixir.bootlin.com/linux/v4.20-rc7/source/drivers/net/wireless/ath/a... [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/
Fixes: 138b41253d9c ("ath9k: parse the device configuration from an OF node") Reviewed-by: Martin Blumenstingl martin.blumenstingl@googlemail.com Tested-by: Martin Blumenstingl martin.blumenstingl@googlemail.com Signed-off-by: Daniel F. Dickinson cshored@thecshore.com Signed-off-by: Kalle Valo kvalo@codeaurora.org Cc: Christian Lamparter chunkeey@gmail.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- drivers/net/wireless/ath/ath9k/init.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-)
--- a/drivers/net/wireless/ath/ath9k/init.c +++ b/drivers/net/wireless/ath/ath9k/init.c @@ -636,15 +636,15 @@ static int ath9k_of_init(struct ath_soft ret = ath9k_eeprom_request(sc, eeprom_name); if (ret) return ret; + + ah->ah_flags &= ~AH_USE_EEPROM; + ah->ah_flags |= AH_NO_EEP_SWAP; }
mac = of_get_mac_address(np); if (mac) ether_addr_copy(common->macaddr, mac);
- ah->ah_flags &= ~AH_USE_EEPROM; - ah->ah_flags |= AH_NO_EEP_SWAP; - return 0; }