[PATCH v2] p54: connect to 11w protected networks

[Christian Lamparter <chunkeey@googlemail.com>]

Previously, it was not possible to connect
to networks which requires 11w to be supported
by the stations.

Note:

As all current (and old) firmwares corrupt
incoming, protected management frames, the
decryption offloading needs to be disabled.

This can be done by loading the p54common
module with the nohwcrypt=1 parameter.

Signed-off-by: Christian Lamparter <chunkeey@googlemail.com>
---
Johannes,

thank you for making me double-check whenever MFP really works!
Unlike carl9170 which generates and receives a great amount of
addba/delba action frames, p54 - being a legacy product - has
no such "easy to use" debug facilities. 

As you feared: the firmware is corrupting incoming management
frames. However, it does so only when a rxkey was configured.
So as a possible trade-off, MFP will only be supported by p54,
when the firmware crypto offloading is relieved of his duties
(disabled). 

Note: Strictly speaking, it would be enough to no longer upload
any rx key which could affect management frames, as the firmware
does not decrypt any frames unless there is a fitting key candidate.

Regards,
	Chr 
---
 drivers/net/wireless/p54/main.c |   11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/drivers/net/wireless/p54/main.c b/drivers/net/wireless/p54/main.c
index 5e91ad0..16b75ec 100644
--- a/drivers/net/wireless/p54/main.c
+++ b/drivers/net/wireless/p54/main.c
@@ -739,6 +739,17 @@ struct ieee80211_hw *p54_init_common(size_t priv_data_len)
 		     IEEE80211_HW_PS_NULLFUNC_STACK |
 		     IEEE80211_HW_REPORTS_TX_ACK_STATUS;
 
+	if (nohwcrypt) {
+		/*
+		 * Only support MFP, if the hardware crypto engine
+		 * is disabled, as the firmware's rx-path corrupts
+		 * incoming CCMP encrypted mgmt frames.
+		 * However, if no rx key is uploaded, the firmware
+		 * passes the unencrypted frame to the driver.
+		 */
+		dev->flags |= IEEE80211_HW_MFP_CAPABLE;
+	}
+
 	dev->wiphy->interface_modes = BIT(NL80211_IFTYPE_STATION) |
 				      BIT(NL80211_IFTYPE_ADHOC) |
 				      BIT(NL80211_IFTYPE_AP) |
-- 
1.7.10.4