wl1251: Implement delayed entry into ELP mode

Implement (slightly) delayed entry into ELP. This will cure several
problems:
  - It works around a firmware race condition if ELP is entered too fast
    after commands (resulting in ELP timeout -traces)
  - It will reduce the number of sleep-wake cycles between already
    scheduled events such as interrupts and tx, hence improving
    performance (less delay in switching between RX and TX)

Signed-off-by: Juuso Oikarinen <juuso.oikarinen@nokia.com>
Reviewed-by: Vidhya Govindan <vidhya.govindan@nokia.com>
Signed-off-by: Kalle Valo <kalle.valo@nokia.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 29 insertions, 5 deletions

diff --git a/drivers/net/wireless/wl12xx/wl1251_ps.c b/drivers/net/wireless/wl12xx/wl1251_ps.c
index c3e348a..9931b19 100644
--- a/drivers/net/wireless/wl12xx/wl1251_ps.c
+++ b/drivers/net/wireless/wl12xx/wl1251_ps.c
@@ -28,17 +28,41 @@
 
 #define WL1251_WAKEUP_TIMEOUT 2000
 
-/* Routines to toggle sleep mode while in ELP */
-void wl1251_ps_elp_sleep(struct wl1251 *wl)
+void wl1251_elp_work(struct work_struct *work)
 {
+	struct delayed_work *dwork;
+	struct wl1251 *wl;
+
+	dwork = container_of(work, struct delayed_work, work);
+	wl = container_of(dwork, struct wl1251, elp_work);
+
+	wl1251_debug(DEBUG_PSM, "elp work");
+
+	mutex_lock(&wl->mutex);
+
 	if (wl->elp || !wl->psm)
-		return;
+		goto out;
 
 	wl1251_debug(DEBUG_PSM, "chip to elp");
-
 	wl1251_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 wl1251_ps_elp_sleep(struct wl1251 *wl)
+{
+	unsigned long delay;
+
+	if (wl->psm) {
+		cancel_delayed_work(&wl->elp_work);
+		delay = msecs_to_jiffies(ELP_ENTRY_DELAY);
+		ieee80211_queue_delayed_work(wl->hw, &wl->elp_work, delay);
+	}
 }
 
 int wl1251_ps_elp_wakeup(struct wl1251 *wl)