[PATCH 89/99] cw1200: Handle WSM_EVENT_RCPI_RSSI correctly

[Dmitry Tarnyagin]

From: Bartosz Markowski <bartosz.markowski at tieto.com>

After switch to RCPI based signal level reports
a RCPI/RSSI EVNTS have been omitted. This patch
fix this and also increse the average count
of samples which are used to report signal change.

A check has been also added to distinguish in receive
indication handler if RCPI needs to be converted
to RSSI.

ST-Ericsson ID: 419276
ST-Ericsson FOSS-OUT ID: NA

Change-Id: I9c0a27181a0d2057db4418878b4b0847f9671372
Signed-off-by: Bartosz Markowski <bartosz.markowski at tieto.com>
Reviewed-on: http://gerrit.lud.stericsson.com/gerrit/49622
---
 drivers/staging/cw1200/ap.c     |    2 +-
 drivers/staging/cw1200/cw1200.h |    1 +
 drivers/staging/cw1200/sta.c    |   25 +++++++++++++++++++++----
 drivers/staging/cw1200/wsm.c    |    7 ++++++-
 4 files changed, 29 insertions(+), 6 deletions(-)

diff --git a/drivers/staging/cw1200/ap.c b/drivers/staging/cw1200/ap.c
index b30afe0..55096cf 100644
--- a/drivers/staging/cw1200/ap.c
+++ b/drivers/staging/cw1200/ap.c
@@ -560,7 +560,7 @@ void cw1200_bss_info_changed(struct ieee80211_hw *dev,
 	}
 	if (changed & (BSS_CHANGED_ASSOC | BSS_CHANGED_CQM)) {
 		struct wsm_rcpi_rssi_threshold threshold = {
-			.rollingAverageCount = 1,
+			.rollingAverageCount = 8,
 		};
 
 #if 0
diff --git a/drivers/staging/cw1200/cw1200.h b/drivers/staging/cw1200/cw1200.h
index 3ae1b91..46b8087 100644
--- a/drivers/staging/cw1200/cw1200.h
+++ b/drivers/staging/cw1200/cw1200.h
@@ -141,6 +141,7 @@ struct cw1200_common {
 	unsigned			cqm_rssi_hyst;
 	unsigned			cqm_tx_failure_thold;
 	unsigned			cqm_tx_failure_count;
+	bool				cqm_use_rssi;
 	int				cqm_link_loss_count;
 	int				cqm_beacon_loss_count;
 	int				channel_switch_in_progress;
diff --git a/drivers/staging/cw1200/sta.c b/drivers/staging/cw1200/sta.c
index fb399eb..7d31378 100644
--- a/drivers/staging/cw1200/sta.c
+++ b/drivers/staging/cw1200/sta.c
@@ -997,11 +997,19 @@ void cw1200_event_handler(struct work_struct *work)
 			break;
 		case WSM_EVENT_RCPI_RSSI:
 		{
-			int rssi = (int)(s8)(event->evt.eventData & 0xFF);
-			int cqm_evt = (rssi <= priv->cqm_rssi_thold) ?
+			/* RSSI: signed Q8.0, RCPI: unsigned Q7.1
+			 * RSSI = RCPI / 2 - 110 */
+			int rcpiRssi = (int)(event->evt.eventData & 0xFF);
+			int cqm_evt;
+			if (priv->cqm_use_rssi)
+				rcpiRssi = (s8)rcpiRssi;
+			else
+				rcpiRssi =  rcpiRssi / 2 - 110;
+
+			cqm_evt = (rcpiRssi <= priv->cqm_rssi_thold) ?
 				NL80211_CQM_RSSI_THRESHOLD_EVENT_LOW :
 				NL80211_CQM_RSSI_THRESHOLD_EVENT_HIGH;
-			sta_printk(KERN_DEBUG "[CQM] RSSI event: %d", rssi);
+			sta_printk(KERN_DEBUG "[CQM] RSSI event: %d", rcpiRssi);
 			ieee80211_cqm_rssi_notify(priv->vif, cqm_evt,
 								GFP_KERNEL);
 			break;
@@ -1158,16 +1166,25 @@ static int cw1200_parse_SDD_file(struct cw1200_common *priv)
 
 int cw1200_setup_mac(struct cw1200_common *priv)
 {
+	int ret = 0;
+
 	/* NOTE: There is a bug in FW: it reports signal
 	* as RSSI if RSSI subscription is enabled.
 	* It's not enough to set WSM_RCPI_RSSI_USE_RSSI. */
+	/* NOTE2: RSSI based reports have been switched to RCPI, since
+	* FW has a bug and RSSI reported values are not stable,
+	* what can leads to signal level oscilations in user-end applications */
 	struct wsm_rcpi_rssi_threshold threshold = {
 		.rssiRcpiMode = WSM_RCPI_RSSI_THRESHOLD_ENABLE |
 		WSM_RCPI_RSSI_DONT_USE_UPPER |
 		WSM_RCPI_RSSI_DONT_USE_LOWER,
 		.rollingAverageCount = 16,
 	};
-	int ret = 0;
+
+	/* Remember the decission here to make sure, we will handle
+	 * the RCPI/RSSI value correctly on WSM_EVENT_RCPI_RSS */
+	if (threshold.rssiRcpiMode & WSM_RCPI_RSSI_USE_RSSI)
+		priv->cqm_use_rssi = true;
 
 	if (!priv->sdd) {
 		const char *sdd_path = NULL;
diff --git a/drivers/staging/cw1200/wsm.c b/drivers/staging/cw1200/wsm.c
index f47950f..245a640 100644
--- a/drivers/staging/cw1200/wsm.c
+++ b/drivers/staging/cw1200/wsm.c
@@ -866,7 +866,7 @@ static int wsm_receive_indication(struct cw1200_common *priv,
 		rx.status = WSM_GET32(buf);
 		rx.channelNumber = WSM_GET16(buf);
 		rx.rxedRate = WSM_GET8(buf);
-		rx.rcpiRssi = (WSM_GET8(buf) / 2 - 110);
+		rx.rcpiRssi = WSM_GET8(buf);
 		rx.flags = WSM_GET32(buf);
 
 		/* FW Workaround: Drop probe resp or
@@ -878,6 +878,11 @@ static int wsm_receive_indication(struct cw1200_common *priv,
 		    ieee80211_is_beacon(hdr->frame_control)))
 			return 0;
 
+		/* If no RSSI subscription has been made,
+		* convert RCPI to RSSI here */
+		if (!priv->cqm_use_rssi)
+			rx.rcpiRssi = rx.rcpiRssi / 2 - 110;
+
 		rx.link_id = link_id;
 		fctl = *(__le16 *)buf->data;
 		hdr_len = buf->data - buf->begin;
-- 
1.7.8.3