mac80211: implement hardware offload for remain-on-channel

This allows drivers to support remain-on-channel
offload if they implement smarter timing or need
to use a device implementation like iwlwifi.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

7 files changed, 287 insertions, 3 deletions

diff --git a/net/mac80211/cfg.c b/net/mac80211/cfg.c
index 5892b0302454..168a6ba8fc28 100644
--- a/net/mac80211/cfg.c
+++ b/net/mac80211/cfg.c
@@ -1593,6 +1593,37 @@ static int ieee80211_set_bitrate_mask(struct wiphy *wiphy,
         return 0;
 }
 
+static int ieee80211_remain_on_channel_hw(struct ieee80211_local *local,
+                                          struct net_device *dev,
+                                          struct ieee80211_channel *chan,
+                                          enum nl80211_channel_type chantype,
+                                          unsigned int duration, u64 *cookie)
+{
+        int ret;
+        u32 random_cookie;
+
+        lockdep_assert_held(&local->mtx);
+
+        if (local->hw_roc_cookie)
+                return -EBUSY;
+        /* must be nonzero */
+        random_cookie = random32() | 1;
+
+        *cookie = random_cookie;
+        local->hw_roc_dev = dev;
+        local->hw_roc_cookie = random_cookie;
+        local->hw_roc_channel = chan;
+        local->hw_roc_channel_type = chantype;
+        local->hw_roc_duration = duration;
+        ret = drv_remain_on_channel(local, chan, chantype, duration);
+        if (ret) {
+                local->hw_roc_channel = NULL;
+                local->hw_roc_cookie = 0;
+        }
+
+        return ret;
+}
+
 static int ieee80211_remain_on_channel(struct wiphy *wiphy,
                                        struct net_device *dev,
                                        struct ieee80211_channel *chan,
@@ -1601,16 +1632,62 @@ static int ieee80211_remain_on_channel(struct wiphy *wiphy,
                                        u64 *cookie)
 {
         struct ieee80211_sub_if_data *sdata = IEEE80211_DEV_TO_SUB_IF(dev);
+        struct ieee80211_local *local = sdata->local;
+
+        if (local->ops->remain_on_channel) {
+                int ret;
+
+                mutex_lock(&local->mtx);
+                ret = ieee80211_remain_on_channel_hw(local, dev,
+                                                     chan, channel_type,
+                                                     duration, cookie);
+                mutex_unlock(&local->mtx);
+
+                return ret;
+        }
 
         return ieee80211_wk_remain_on_channel(sdata, chan, channel_type,
                                               duration, cookie);
 }
 
+static int ieee80211_cancel_remain_on_channel_hw(struct ieee80211_local *local,
+                                                 u64 cookie)
+{
+        int ret;
+
+        lockdep_assert_held(&local->mtx);
+
+        if (local->hw_roc_cookie != cookie)
+                return -ENOENT;
+
+        ret = drv_cancel_remain_on_channel(local);
+        if (ret)
+                return ret;
+
+        local->hw_roc_cookie = 0;
+        local->hw_roc_channel = NULL;
+
+        ieee80211_recalc_idle(local);
+
+        return 0;
+}
+
 static int ieee80211_cancel_remain_on_channel(struct wiphy *wiphy,
                                               struct net_device *dev,
                                               u64 cookie)
 {
         struct ieee80211_sub_if_data *sdata = IEEE80211_DEV_TO_SUB_IF(dev);
+        struct ieee80211_local *local = sdata->local;
+
+        if (local->ops->cancel_remain_on_channel) {
+                int ret;
+
+                mutex_lock(&local->mtx);
+                ret = ieee80211_cancel_remain_on_channel_hw(local, cookie);
+                mutex_unlock(&local->mtx);
+
+                return ret;
+        }
 
         return ieee80211_wk_cancel_remain_on_channel(sdata, cookie);
 }
@@ -1662,6 +1739,12 @@ static int ieee80211_mgmt_tx(struct wiphy *wiphy, struct net_device *dev,
              channel_type != local->_oper_channel_type))
                 is_offchan = true;
 
+        if (chan == local->hw_roc_channel) {
+                /* TODO: check channel type? */
+                is_offchan = false;
+                flags |= IEEE80211_TX_CTL_TX_OFFCHAN;
+        }
+
         if (is_offchan && !offchan)
                 return -EBUSY;
 
diff --git a/net/mac80211/driver-ops.h b/net/mac80211/driver-ops.h
index af0c4398cceb..98d589960a49 100644
--- a/net/mac80211/driver-ops.h
+++ b/net/mac80211/driver-ops.h
@@ -465,4 +465,34 @@ static inline int drv_get_antenna(struct ieee80211_local *local,
         return ret;
 }
 
+static inline int drv_remain_on_channel(struct ieee80211_local *local,
+                                        struct ieee80211_channel *chan,
+                                        enum nl80211_channel_type chantype,
+                                        unsigned int duration)
+{
+        int ret;
+
+        might_sleep();
+
+        trace_drv_remain_on_channel(local, chan, chantype, duration);
+        ret = local->ops->remain_on_channel(&local->hw, chan, chantype,
+                                            duration);
+        trace_drv_return_int(local, ret);
+
+        return ret;
+}
+
+static inline int drv_cancel_remain_on_channel(struct ieee80211_local *local)
+{
+        int ret;
+
+        might_sleep();
+
+        trace_drv_cancel_remain_on_channel(local);
+        ret = local->ops->cancel_remain_on_channel(&local->hw);
+        trace_drv_return_int(local, ret);
+
+        return ret;
+}
+
 #endif /* __MAC80211_DRIVER_OPS */
diff --git a/net/mac80211/driver-trace.h b/net/mac80211/driver-trace.h
index c2772f23ac9c..49c84218b2f4 100644
--- a/net/mac80211/driver-trace.h
+++ b/net/mac80211/driver-trace.h
@@ -933,6 +933,50 @@ TRACE_EVENT(drv_get_antenna,
         )
 );
 
+TRACE_EVENT(drv_remain_on_channel,
+        TP_PROTO(struct ieee80211_local *local, struct ieee80211_channel *chan,
+                 enum nl80211_channel_type chantype, unsigned int duration),
+
+        TP_ARGS(local, chan, chantype, duration),
+
+        TP_STRUCT__entry(
+                LOCAL_ENTRY
+                __field(int, center_freq)
+                __field(int, channel_type)
+                __field(unsigned int, duration)
+        ),
+
+        TP_fast_assign(
+                LOCAL_ASSIGN;
+                __entry->center_freq = chan->center_freq;
+                __entry->channel_type = chantype;
+                __entry->duration = duration;
+        ),
+
+        TP_printk(
+                LOCAL_PR_FMT " freq:%dMHz duration:%dms",
+                LOCAL_PR_ARG, __entry->center_freq, __entry->duration
+        )
+);
+
+TRACE_EVENT(drv_cancel_remain_on_channel,
+        TP_PROTO(struct ieee80211_local *local),
+
+        TP_ARGS(local),
+
+        TP_STRUCT__entry(
+                LOCAL_ENTRY
+        ),
+
+        TP_fast_assign(
+                LOCAL_ASSIGN;
+        ),
+
+        TP_printk(
+                LOCAL_PR_FMT, LOCAL_PR_ARG
+        )
+);
+
 /*
  * Tracing for API calls that drivers call.
  */
@@ -1170,6 +1214,42 @@ TRACE_EVENT(api_chswitch_done,
         )
 );
 
+TRACE_EVENT(api_ready_on_channel,
+        TP_PROTO(struct ieee80211_local *local),
+
+        TP_ARGS(local),
+
+        TP_STRUCT__entry(
+                LOCAL_ENTRY
+        ),
+
+        TP_fast_assign(
+                LOCAL_ASSIGN;
+        ),
+
+        TP_printk(
+                LOCAL_PR_FMT, LOCAL_PR_ARG
+        )
+);
+
+TRACE_EVENT(api_remain_on_channel_expired,
+        TP_PROTO(struct ieee80211_local *local),
+
+        TP_ARGS(local),
+
+        TP_STRUCT__entry(
+                LOCAL_ENTRY
+        ),
+
+        TP_fast_assign(
+                LOCAL_ASSIGN;
+        ),
+
+        TP_printk(
+                LOCAL_PR_FMT, LOCAL_PR_ARG
+        )
+);
+
 /*
  * Tracing for internal functions
  * (which may also be called in response to driver calls)
diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h
index 95cdd2a3f809..f866af8de5ac 100644
--- a/net/mac80211/ieee80211_i.h
+++ b/net/mac80211/ieee80211_i.h
@@ -951,6 +951,13 @@ struct ieee80211_local {
         } debugfs;
 #endif
 
+        struct ieee80211_channel *hw_roc_channel;
+        struct net_device *hw_roc_dev;
+        struct work_struct hw_roc_start, hw_roc_done;
+        enum nl80211_channel_type hw_roc_channel_type;
+        unsigned int hw_roc_duration;
+        u32 hw_roc_cookie;
+
         /* dummy netdev for use w/ NAPI */
         struct net_device napi_dev;
 
@@ -1142,6 +1149,7 @@ void ieee80211_offchannel_stop_beaconing(struct ieee80211_local *local);
 void ieee80211_offchannel_stop_station(struct ieee80211_local *local);
 void ieee80211_offchannel_return(struct ieee80211_local *local,
                                  bool enable_beaconing);
+void ieee80211_hw_roc_setup(struct ieee80211_local *local);
 
 /* interface handling */
 int ieee80211_iface_init(void);
diff --git a/net/mac80211/iface.c b/net/mac80211/iface.c
index b6db237672ff..8acba456744e 100644
--- a/net/mac80211/iface.c
+++ b/net/mac80211/iface.c
@@ -1264,7 +1264,7 @@ u32 __ieee80211_recalc_idle(struct ieee80211_local *local)
 {
         struct ieee80211_sub_if_data *sdata;
         int count = 0;
-        bool working = false, scanning = false;
+        bool working = false, scanning = false, hw_roc = false;
         struct ieee80211_work *wk;
         unsigned int led_trig_start = 0, led_trig_stop = 0;
 
@@ -1308,6 +1308,9 @@ u32 __ieee80211_recalc_idle(struct ieee80211_local *local)
                 local->scan_sdata->vif.bss_conf.idle = false;
         }
 
+        if (local->hw_roc_channel)
+                hw_roc = true;
+
         list_for_each_entry(sdata, &local->interfaces, list) {
                 if (sdata->old_idle == sdata->vif.bss_conf.idle)
                         continue;
@@ -1316,7 +1319,7 @@ u32 __ieee80211_recalc_idle(struct ieee80211_local *local)
                 ieee80211_bss_info_change_notify(sdata, BSS_CHANGED_IDLE);
         }
 
-        if (working || scanning)
+        if (working || scanning || hw_roc)
                 led_trig_start |= IEEE80211_TPT_LEDTRIG_FL_WORK;
         else
                 led_trig_stop |= IEEE80211_TPT_LEDTRIG_FL_WORK;
@@ -1328,6 +1331,8 @@ u32 __ieee80211_recalc_idle(struct ieee80211_local *local)
 
         ieee80211_mod_tpt_led_trig(local, led_trig_start, led_trig_stop);
 
+        if (hw_roc)
+                return ieee80211_idle_off(local, "hw remain-on-channel");
         if (working)
                 return ieee80211_idle_off(local, "working");
         if (scanning)
diff --git a/net/mac80211/main.c b/net/mac80211/main.c
index 4b088b3c25e8..485d36bc9a46 100644
--- a/net/mac80211/main.c
+++ b/net/mac80211/main.c
@@ -609,6 +609,8 @@ struct ieee80211_hw *ieee80211_alloc_hw(size_t priv_data_len,
 
         ieee80211_led_names(local);
 
+        ieee80211_hw_roc_setup(local);
+
         return local_to_hw(local);
 }
 EXPORT_SYMBOL(ieee80211_alloc_hw);
@@ -753,7 +755,8 @@ int ieee80211_register_hw(struct ieee80211_hw *hw)
                 }
         }
 
-        local->hw.wiphy->max_remain_on_channel_duration = 5000;
+        if (!local->ops->remain_on_channel)
+                local->hw.wiphy->max_remain_on_channel_duration = 5000;
 
         result = wiphy_register(local->hw.wiphy);
         if (result < 0)
diff --git a/net/mac80211/offchannel.c b/net/mac80211/offchannel.c
index 4b564091e51d..49b9ec22d9b6 100644
--- a/net/mac80211/offchannel.c
+++ b/net/mac80211/offchannel.c
@@ -14,6 +14,7 @@
  */
 #include <net/mac80211.h>
 #include "ieee80211_i.h"
+#include "driver-trace.h"
 
 /*
  * inform AP that we will go to sleep so that it will buffer the frames
@@ -190,3 +191,77 @@ void ieee80211_offchannel_return(struct ieee80211_local *local,
         }
         mutex_unlock(&local->iflist_mtx);
 }
+
+static void ieee80211_hw_roc_start(struct work_struct *work)
+{
+        struct ieee80211_local *local =
+                container_of(work, struct ieee80211_local, hw_roc_start);
+
+        mutex_lock(&local->mtx);
+
+        if (!local->hw_roc_channel) {
+                mutex_unlock(&local->mtx);
+                return;
+        }
+
+        ieee80211_recalc_idle(local);
+
+        cfg80211_ready_on_channel(local->hw_roc_dev, local->hw_roc_cookie,
+                                  local->hw_roc_channel,
+                                  local->hw_roc_channel_type,
+                                  local->hw_roc_duration,
+                                  GFP_KERNEL);
+        mutex_unlock(&local->mtx);
+}
+
+void ieee80211_ready_on_channel(struct ieee80211_hw *hw)
+{
+        struct ieee80211_local *local = hw_to_local(hw);
+
+        trace_api_ready_on_channel(local);
+
+        ieee80211_queue_work(hw, &local->hw_roc_start);
+}
+EXPORT_SYMBOL_GPL(ieee80211_ready_on_channel);
+
+static void ieee80211_hw_roc_done(struct work_struct *work)
+{
+        struct ieee80211_local *local =
+                container_of(work, struct ieee80211_local, hw_roc_done);
+
+        mutex_lock(&local->mtx);
+
+        if (!local->hw_roc_channel) {
+                mutex_unlock(&local->mtx);
+                return;
+        }
+
+        cfg80211_remain_on_channel_expired(local->hw_roc_dev,
+                                           local->hw_roc_cookie,
+                                           local->hw_roc_channel,
+                                           local->hw_roc_channel_type,
+                                           GFP_KERNEL);
+
+        local->hw_roc_channel = NULL;
+        local->hw_roc_cookie = 0;
+
+        ieee80211_recalc_idle(local);
+
+        mutex_unlock(&local->mtx);
+}
+
+void ieee80211_remain_on_channel_expired(struct ieee80211_hw *hw)
+{
+        struct ieee80211_local *local = hw_to_local(hw);
+
+        trace_api_remain_on_channel_expired(local);
+
+        ieee80211_queue_work(hw, &local->hw_roc_done);
+}
+EXPORT_SYMBOL_GPL(ieee80211_remain_on_channel_expired);
+
+void ieee80211_hw_roc_setup(struct ieee80211_local *local)
+{
+        INIT_WORK(&local->hw_roc_start, ieee80211_hw_roc_start);
+        INIT_WORK(&local->hw_roc_done, ieee80211_hw_roc_done);
+}