Wifi: Filter usable channels by Coex, Concurrency

Add ability to filter usable channnels due to coex &
concurrency limitations. Normally in standalone mode,
list of usable channels is dictated by regulatory. But
list of usable channels could be additionally limited
due to coex and also due to concurrency limitations.

Bug: 160212907
Test: Using halutil
Change-Id: Iafde3b4fe9ca8986404ee078ed0a1a31062a4bbb

1 files changed, 54 insertions, 14 deletions

diff --git a/include/hardware_legacy/wifi_hal.h b/include/hardware_legacy/wifi_hal.h
index c76ee72..74cabb6 100644
--- a/include/hardware_legacy/wifi_hal.h
+++ b/include/hardware_legacy/wifi_hal.h
@@ -129,14 +129,52 @@ typedef struct {
 } wifi_channel_spec;
 
 /*
- * wifi_usable_channel - modes supported on a channel and operating bandwidth
+ * wifi_usable_channel specifies a channel frequency, bandwidth, and bitmask
+ * of modes allowed on the channel.
  */
 typedef struct {
-    wifi_channel freq; // channel frequency in MHz
-    wifi_channel_width width; // channel operating width (20, 40, 80, 160 etc.)
-    u32 iface_mode_mask; // BIT MASK of BIT(WIFI_INTERFACE_*) represented by wifi_interface_mode */
+    /* Channel frequency in MHz */
+    wifi_channel freq;
+    /* Channel operating width (20, 40, 80, 160 etc.) */
+    wifi_channel_width width;
+    /* BIT MASK of BIT(WIFI_INTERFACE_*) represented by |wifi_interface_mode|
+     * Bitmask does not represent concurrency.
+     * Examples:
+     * - If a channel is usable only for STA, then only the WIFI_INTERFACE_STA
+     *   bit would be set for that channel.
+     * - If 5GHz SAP is not allowed, then none of the 5GHz channels will have
+     *   WIFI_INTERFACE_SOFTAP bit set.
+     * Note: TDLS bit is set only if there is a STA connection. TDLS bit is set
+     * on non-STA channels only if TDLS off channel is supported.
+     */
+    u32 iface_mode_mask;
 } wifi_usable_channel;
 
+/*
+ * wifi_usable_channel_filter
+ */
+typedef enum {
+  /* Filter Wifi channels that should be avoided due to cellular coex
+   * restrictions. Some Wifi channels can have extreme interference
+   * from/to cellular due to short frequency seperation with neighboring
+   * cellular channels or when there is harmonic and intermodulation
+   * interference. Channels which only have some performance degradation
+   * (e.g. power back off is sufficient to deal with coexistence issue)
+   * can be included and should not be filtered out.
+   */
+  WIFI_USABLE_CHANNEL_FILTER_CELLULAR_COEXISTENCE  = 1 << 0,
+  /* Filter channels due to concurrency state.
+   * Examples:
+   * - 5GHz SAP operation may be supported in standalone mode, but if
+   *  there is STA connection on 5GHz DFS channel, none of the 5GHz
+   *  channels are usable for SAP if device does not support DFS SAP mode.
+   * - P2P GO may not be supported on indoor channels in EU during
+   *  standalone mode but if there is a STA connection on indoor channel,
+   *  P2P GO may be supported by some vendors on the same STA channel.
+   */
+  WIFI_USABLE_CHANNEL_FILTER_CONCURRENCY  = 1 << 1,
+} wifi_usable_channel_filter;
+
 typedef enum {
     WIFI_SUCCESS = 0,
     WIFI_ERROR_NONE = 0,
@@ -821,20 +859,22 @@ typedef struct {
      * @param band_mask BIT MASK of WLAN_MAC* as represented by |wlan_mac_band|
      * @param iface_mode_mask BIT MASK of BIT(WIFI_INTERFACE_*) represented by
      *        |wifi_interface_mode|. Bitmask respresents all the modes that the
-     *        caller is interested in (e.g. STA, SAP, CLI, GO, TDLS, NAN).
-     *        Note: Bitmask does not represent concurrency matrix.
+     *        caller is interested in (e.g. STA, SAP, WFD-CLI, WFD-GO, TDLS, NAN).
+     *        Note: Bitmask does not represent concurrency matrix. If the caller
+     *        is interested in CLI, GO modes, the iface_mode_mask would be set
+     *        to WIFI_INTERFACE_P2P_CLIENT|WIFI_INTERFACE_P2P_GO.
+     * @param filter_mask BIT MASK of WIFI_USABLE_CHANNEL_FILTER_* represented by
+     *        |wifi_usable_channel_filter|. Indicates if the channel list should
+     *        be filtered based on additional criteria. If filter_mask is not
+     *        specified, driver should return list of usable channels purely
+     *        based on regulatory constraints.
      * @param max_size maximum number of |wifi_usable_channel|
-     * @param size actual number of |wifi_usable_channel|
+     * @param size actual number of |wifi_usable_channel| entries returned by driver
      * @param channels list of usable channels represented by |wifi_usable_channel|
-     *        Each |wifi_usable_channel| entry specifies a channel frequency,
-     *        bandwidth, and bitmask of modes (e.g. STA, SAP, CLI, GO, TDLS, NAN)
-     *        allowed on the channel.
-     *        Note: TDLS bit is set only if there is a STA connection. TDLS bit is
-     *        set on non-STA channels only if TDLS off channel is supported.
-     *        Note: Bitmask in |wifi_usable_channel| does not represent concurrency.
      */
     wifi_error (*wifi_get_usable_channels)(wifi_handle handle, u32 band_mask, u32 iface_mode_mask,
-                                           u32 max_size, u32* size, wifi_usable_channel* channels);
+                                           u32 filter_mask, u32 max_size, u32* size,
+                                           wifi_usable_channel* channels);
 
     /*
      * when adding new functions make sure to add stubs in