[PATCH 4/6] Add a bitrate threshold config hook in mac80211

[PATCH 4/6] Add a bitrate threshold config hook in mac80211

[Paul Stewart]

Add a hook in mac80211 to accept bitrate threshold configuration
calls from nl80211.  This assigns a couple new variables in the
bss and ifmgd structs.

Signed-off-by: Paul Stewart <pstew@google.com>

---
 include/net/mac80211.h     |    3 +++
 net/mac80211/cfg.c         |   17 +++++++++++++++++
 net/mac80211/ieee80211_i.h |   16 ++++++++++++++++
 3 files changed, 36 insertions(+), 0 deletions(-)

diff --git a/include/net/mac80211.h b/include/net/mac80211.h
index 9fdf982..1c2473c 100644
--- a/include/net/mac80211.h
+++ b/include/net/mac80211.h
@@ -215,6 +215,8 @@ enum ieee80211_bss_change {
  * @cqm_rssi_thold: Connection quality monitor RSSI threshold, a zero value
  *	implies disabled
  * @cqm_rssi_hyst: Connection quality monitor RSSI hysteresis
+ * @cqm_bitrate_thold: Connection quality monitor bitrate threshold, a zero
+ *	value implies disabled
  * @arp_addr_list: List of IPv4 addresses for hardware ARP filtering. The
  *	may filter ARP queries targeted for other addresses than listed here.
  *	The driver must allow ARP queries targeted for all address listed here
@@ -247,6 +249,7 @@ struct ieee80211_bss_conf {
 	u16 ht_operation_mode;
 	s32 cqm_rssi_thold;
 	u32 cqm_rssi_hyst;
+	u32 cqm_bitrate_thold;
 	enum nl80211_channel_type channel_type;
 	__be32 arp_addr_list[IEEE80211_BSS_ARP_ADDR_LIST_LEN];
 	u8 arp_addr_cnt;
diff --git a/net/mac80211/cfg.c b/net/mac80211/cfg.c
index 18bd0e5..520619c 100644
--- a/net/mac80211/cfg.c
+++ b/net/mac80211/cfg.c
@@ -1498,6 +1498,22 @@ static int ieee80211_set_cqm_rssi_config(struct wiphy *wiphy,
 	return 0;
 }
 
+static int ieee80211_set_cqm_bitrate_config(struct wiphy *wiphy,
+					    struct net_device *dev,
+					    u32 bitrate_thold)
+{
+	struct ieee80211_sub_if_data *sdata = IEEE80211_DEV_TO_SUB_IF(dev);
+	struct ieee80211_vif *vif = &sdata->vif;
+	struct ieee80211_bss_conf *bss_conf = &vif->bss_conf;
+
+	bss_conf->cqm_bitrate_thold = bitrate_thold;
+	sdata->u.mgd.last_cqm_bitrate = 0;
+	memset(&sdata->u.mgd.last_cqm_tx_rate, 0,
+	       sizeof(sdata->u.mgd.last_cqm_tx_rate));
+
+	return 0;
+}
+
 static int ieee80211_set_bitrate_mask(struct wiphy *wiphy,
 				      struct net_device *dev,
 				      const u8 *addr,
@@ -1672,5 +1688,6 @@ struct cfg80211_ops mac80211_config_ops = {
 	.cancel_remain_on_channel = ieee80211_cancel_remain_on_channel,
 	.mgmt_tx = ieee80211_mgmt_tx,
 	.set_cqm_rssi_config = ieee80211_set_cqm_rssi_config,
+	.set_cqm_bitrate_config = ieee80211_set_cqm_bitrate_config,
 	.mgmt_frame_register = ieee80211_mgmt_frame_register,
 };
diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h
index b80c386..02bf0b7 100644
--- a/net/mac80211/ieee80211_i.h
+++ b/net/mac80211/ieee80211_i.h
@@ -338,6 +338,7 @@ enum ieee80211_sta_flags {
 	IEEE80211_STA_UAPSD_ENABLED	= BIT(7),
 	IEEE80211_STA_NULLFUNC_ACKED	= BIT(8),
 	IEEE80211_STA_RESET_SIGNAL_AVE	= BIT(9),
+	IEEE80211_STA_TX_RATE_CHANGED	= BIT(10),
 };
 
 struct ieee80211_if_managed {
@@ -406,6 +407,18 @@ struct ieee80211_if_managed {
 	 * generated for the current association.
 	 */
 	int last_cqm_event_signal;
+
+	/*
+	 * Last bitrate value sent as an event to signal quality listeners.
+	 * This is a u32 in units of 1000 bits per second.
+	 */
+	u32 last_cqm_bitrate;
+
+	/*
+	 * Previous transmit rate.  Used to detect whether the transmit rate
+	 * for the previous packet is different from the one before it.
+	 */
+	struct ieee80211_tx_rate last_cqm_tx_rate;
 };
 
 struct ieee80211_if_ibss {
@@ -723,6 +736,9 @@ struct ieee80211_local {
 	/* used to reconfigure hardware SM PS */
 	struct work_struct recalc_smps;
 
+	/* used to notify listeners of changes to tx bitrate */
+	struct work_struct rate_notify;
+
 	/* aggregated multicast list */
 	struct netdev_hw_addr_list mc_list;
 
-- 
1.7.1

Re: [PATCH 4/6] Add a bitrate threshold config hook in mac80211

[Johannes Berg]

On Wed, 2010-10-13 at 15:17 -0700, Paul Stewart wrote:
> Add a hook in mac80211 to accept bitrate threshold configuration
> calls from nl80211.  This assigns a couple new variables in the
> bss and ifmgd structs.

> @@ -247,6 +249,7 @@ struct ieee80211_bss_conf {
>  	u16 ht_operation_mode;
>  	s32 cqm_rssi_thold;
>  	u32 cqm_rssi_hyst;
> +	u32 cqm_bitrate_thold;

Since there's no way for drivers to utilise this, don't add it in public
API.

johannes

Re: [PATCH 4/6] Add a bitrate threshold config hook in mac80211

[Johannes Berg]

[list added back]

On Thu, 2010-10-14 at 06:42 -0700, Paul Stewart wrote:

> >> +     u32 cqm_bitrate_thold;
> >
> > Since there's no way for drivers to utilise this, don't add it in public
> > API.
> 
> I disagree here.  I don't see a reason why a other drivers would not
> be able to take advantage of this feature, much the same as some of
> them support rssi thresholds.  They can calculate their own last
> transmitted bitrate and trigger cqm events using cfg80211 just as well
> as mac80211 can.

No, they can't, for one they don't have access to the netdev. So at
least mac80211 would have to provide wrappers. And there would also have
to be capability bits so that mac80211 doesn't actually do all of this
in software when the driver does it, avoiding double notifications and
overhead.

johannes