mac80211: support hw scan while idle

Currently, mac80211 goes to idle-off before starting a scan.
However, some devices that implement hw scan might not
need going idle-off in order to perform a hw scan, and
thus saving some energy and simplifying their state machine.

(Note that this is also the case for sched scan - it
currently doesn't make mac80211 go idle-off)

Add a new flag to indicate support for hw scan while idle.

Signed-off-by: Eliad Peller <eliad@wizery.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

4 files changed, 12 insertions, 1 deletions

diff --git a/include/net/mac80211.h b/include/net/mac80211.h
index 922313f0b39b..cbff4f94a200 100644
--- a/include/net/mac80211.h
+++ b/include/net/mac80211.h
@@ -1164,6 +1164,10 @@ enum sta_notify_cmd {
  * @IEEE80211_HW_TX_AMPDU_SETUP_IN_HW: The device handles TX A-MPDU session
  *      setup strictly in HW. mac80211 should not attempt to do this in
  *      software.
+ *
+ * @IEEE80211_HW_SCAN_WHILE_IDLE: The device can do hw scan while
+ *      being idle (i.e. mac80211 doesn't have to go idle-off during the
+ *      the scan).
  */
 enum ieee80211_hw_flags {
         IEEE80211_HW_HAS_RATE_CONTROL                   = 1<<0,
@@ -1190,6 +1194,7 @@ enum ieee80211_hw_flags {
         IEEE80211_HW_SUPPORTS_PER_STA_GTK               = 1<<21,
         IEEE80211_HW_AP_LINK_PS                         = 1<<22,
         IEEE80211_HW_TX_AMPDU_SETUP_IN_HW               = 1<<23,
+        IEEE80211_HW_SCAN_WHILE_IDLE                    = 1<<24,
 };
 
 /**
diff --git a/net/mac80211/debugfs.c b/net/mac80211/debugfs.c
index affe64be9092..483e96ed95c1 100644
--- a/net/mac80211/debugfs.c
+++ b/net/mac80211/debugfs.c
@@ -263,6 +263,8 @@ static ssize_t hwflags_read(struct file *file, char __user *user_buf,
                 sf += snprintf(buf + sf, mxln - sf, "AP_LINK_PS\n");
         if (local->hw.flags & IEEE80211_HW_TX_AMPDU_SETUP_IN_HW)
                 sf += snprintf(buf + sf, mxln - sf, "TX_AMPDU_SETUP_IN_HW\n");
+        if (local->hw.flags & IEEE80211_HW_SCAN_WHILE_IDLE)
+                sf += snprintf(buf + sf, mxln - sf, "SCAN_WHILE_IDLE\n");
 
         rv = simple_read_from_buffer(user_buf, count, ppos, buf, strlen(buf));
         kfree(buf);
diff --git a/net/mac80211/iface.c b/net/mac80211/iface.c
index 19f0818eba78..6b3cd65d1e07 100644
--- a/net/mac80211/iface.c
+++ b/net/mac80211/iface.c
@@ -1332,7 +1332,8 @@ u32 __ieee80211_recalc_idle(struct ieee80211_local *local)
                 wk->sdata->vif.bss_conf.idle = false;
         }
 
-        if (local->scan_sdata) {
+        if (local->scan_sdata &&
+            !(local->hw.flags & IEEE80211_HW_SCAN_WHILE_IDLE)) {
                 scanning = true;
                 local->scan_sdata->vif.bss_conf.idle = false;
         }
diff --git a/net/mac80211/main.c b/net/mac80211/main.c
index 362e89d6d467..831a5bd44fd0 100644
--- a/net/mac80211/main.c
+++ b/net/mac80211/main.c
@@ -697,6 +697,9 @@ int ieee80211_register_hw(struct ieee80211_hw *hw)
             )
                 return -EINVAL;
 
+        if ((hw->flags & IEEE80211_HW_SCAN_WHILE_IDLE) && !local->ops->hw_scan)
+                return -EINVAL;
+
         if (hw->max_report_rates == 0)
                 hw->max_report_rates = hw->max_rates;