wl1271: Implement delayed entry into ELP

Implement delayed entry into ELP. This will promote the following:
 - Less redundant sleep/wake cycles (better perf)
 - Avoids known firmware issues with going to ELP too fast after an
   operation

Signed-off-by: Juuso Oikarinen <juuso.oikarinen@nokia.com>
Reviewed-by: Vidhya Govindan <vidhya.govindan@nokia.com>
Signed-off-by: Luciano Coelho <luciano.coelho@nokia.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

drivers/net/wireless/wl12xx/wl1271.h

@@ -373,6 +373,7 @@ struct wl1271 {
 	bool elp;
 
 	struct completion *elp_compl;
+	struct delayed_work elp_work;
 
 	/* we can be in psm, but not in elp, we have to differentiate */
 	bool psm;

drivers/net/wireless/wl12xx/wl1271_main.c

@@ -1226,6 +1226,7 @@ static int __devinit wl1271_probe(struct spi_device *spi)
 	skb_queue_head_init(&wl->tx_queue);
 
 	INIT_WORK(&wl->filter_work, wl1271_filter_work);
+	INIT_DELAYED_WORK(&wl->elp_work, wl1271_elp_work);
 	wl->channel = WL1271_DEFAULT_CHANNEL;
 	wl->scanning = false;
 	wl->default_key = 0;

drivers/net/wireless/wl12xx/wl1271_ps.c

@@ -27,25 +27,43 @@
 
 #define WL1271_WAKEUP_TIMEOUT 500
 
-/* Routines to toggle sleep mode while in ELP */
-void wl1271_ps_elp_sleep(struct wl1271 *wl)
+void wl1271_elp_work(struct work_struct *work)
 {
+	struct delayed_work *dwork;
+	struct wl1271 *wl;
+
+	dwork = container_of(work, struct delayed_work, work);
+	wl = container_of(dwork, struct wl1271, elp_work);
+
+	wl1271_debug(DEBUG_PSM, "elp work");
+
+	mutex_lock(&wl->mutex);
+
 	/*
-	 * FIXME: due to a problem in the firmware (causing a firmware
-	 * crash), ELP entry is prevented below. Remove the "true" to
-	 * re-enable ELP entry.
+	 * FIXME: below, by means of the "true", ELP has been disabled for now
+	 * to work around a firmware bug. To be enabled upon receiving a new
+	 * firmware version.
 	 */
 	if (true || wl->elp || !wl->psm)
-		return;
+		goto out;
 
-	/*
-	 * Go to ELP unless there is work already pending - pending work
-	 * will immediately wakeup the chipset anyway.
-	 */
-	if (!work_pending(&wl->irq_work) && !work_pending(&wl->tx_work)) {
-		wl1271_debug(DEBUG_PSM, "chip to elp");
-		wl1271_write32(wl, HW_ACCESS_ELP_CTRL_REG_ADDR, ELPCTRL_SLEEP);
-		wl->elp = true;
+	wl1271_debug(DEBUG_PSM, "chip to elp");
+	wl1271_write32(wl, HW_ACCESS_ELP_CTRL_REG_ADDR, ELPCTRL_SLEEP);
+	wl->elp = true;
+
+out:
+	mutex_unlock(&wl->mutex);
+}
+
+#define ELP_ENTRY_DELAY  5
+
+/* Routines to toggle sleep mode while in ELP */
+void wl1271_ps_elp_sleep(struct wl1271 *wl)
+{
+	if (wl->psm) {
+		cancel_delayed_work(&wl->elp_work);
+		ieee80211_queue_delayed_work(wl->hw, &wl->elp_work,
+					msecs_to_jiffies(ELP_ENTRY_DELAY));
 	}
 }
 

drivers/net/wireless/wl12xx/wl1271_ps.h

@@ -30,6 +30,6 @@
 int wl1271_ps_set_mode(struct wl1271 *wl, enum wl1271_cmd_ps_mode mode);
 void wl1271_ps_elp_sleep(struct wl1271 *wl);
 int wl1271_ps_elp_wakeup(struct wl1271 *wl, bool chip_awake);
-
+void wl1271_elp_work(struct work_struct *work);
 
 #endif /* __WL1271_PS_H__ */