ath9k_htc: add new WMI_REG_RMW_CMDID command

Since usb bus add extra delay on each request, a command
with read + write requests is too expensive. We can dramtically
reduce usb load by moving this command to firmware.

In my tests, this patch will reduce channel scan time
for about 5-10 seconds.

Signed-off-by: Oleksij Rempel <linux@rempel-privat.de>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>

drivers/net/wireless/ath/ath9k/wmi.h

@@ -112,6 +112,7 @@ enum wmi_cmd_id {
 	WMI_TX_STATS_CMDID,
 	WMI_RX_STATS_CMDID,
 	WMI_BITRATE_MASK_CMDID,
+	WMI_REG_RMW_CMDID,
 };
 
 enum wmi_event_id {
@@ -125,12 +126,19 @@ enum wmi_event_id {
 };
 
 #define MAX_CMD_NUMBER 62
+#define MAX_RMW_CMD_NUMBER 15
 
 struct register_write {
 	__be32 reg;
 	__be32 val;
 };
 
+struct register_rmw {
+	__be32 reg;
+	__be32 set;
+	__be32 clr;
+} __packed;
+
 struct ath9k_htc_tx_event {
 	int count;
 	struct __wmi_event_txstatus txs;
@@ -156,10 +164,18 @@ struct wmi {
 
 	spinlock_t wmi_lock;
 
+	/* multi write section */
 	atomic_t mwrite_cnt;
 	struct register_write multi_write[MAX_CMD_NUMBER];
 	u32 multi_write_idx;
 	struct mutex multi_write_mutex;
+
+	/* multi rmw section */
+	atomic_t m_rmw_cnt;
+	struct register_rmw multi_rmw[MAX_RMW_CMD_NUMBER];
+	u32 multi_rmw_idx;
+	struct mutex multi_rmw_mutex;
+
 };
 
 struct wmi *ath9k_init_wmi(struct ath9k_htc_priv *priv);