WLAN: CW1200: Power management is implemnted.

Power management is on in this commit. Device is configured
in quiescent mode when idle and in dose mode when operating.
BH always checks if device is awake before trying to access it.
Timeout for putting device back to sleep is 1 second after
last device access.

Verification with WSM_A21.05.0288 shows that device is staying
awake even in quiescent mode. Bug in firmware? To be investigated.

Signed-off-by: Dmitry Tarnyagin <dmitry.tarnyagin@stericsson.com>

1 files changed, 75 insertions, 7 deletions

diff --git a/drivers/staging/cw1200/bh.c b/drivers/staging/cw1200/bh.c
index 94711af1ea3..286d4cb43b7 100644
--- a/drivers/staging/cw1200/bh.c
+++ b/drivers/staging/cw1200/bh.c
@@ -31,7 +31,7 @@
 
 static int cw1200_bh(void *arg);
 
-/* TODO: Werify these numbers with WSM specification. */
+/* TODO: Verify these numbers with WSM specification. */
 #define DOWNLOAD_BLOCK_SIZE_WR	(0x1000 - 4)
 /* an SPI message cannot be bigger than (2"12-1)*2 bytes
  * "*2" to cvt to bytes */
@@ -178,6 +178,42 @@ static inline int cw1200_bh_read_ctrl_reg(struct cw1200_common *priv,
 	return ret;
 }
 
+static int cw1200_device_wakeup(struct cw1200_common *priv)
+{
+	u16 ctrl_reg;
+	int ret;
+
+	bh_printk(KERN_DEBUG "[BH] Device wakeup.\n");
+
+	/* To force the device to be always-on, the host sets WLAN_UP to 1 */
+	ret = cw1200_reg_write_16(priv, ST90TDS_CONTROL_REG_ID,
+			ST90TDS_CONT_WUP_BIT);
+	if (WARN_ON(ret))
+		return ret;
+
+	ret = cw1200_bh_read_ctrl_reg(priv, &ctrl_reg);
+	if (WARN_ON(ret))
+		return ret;
+
+	/* If the device returns WLAN_RDY as 1, the device is active and will
+	 * remain active. */
+	if (ctrl_reg & ST90TDS_CONT_RDY_BIT) {
+		bh_printk(KERN_DEBUG "[BH] Device awake.\n");
+		return 1;
+	}
+
+	return 0;
+}
+
+/* Must be called from BH thraed. */
+void cw1200_enable_powersave(struct cw1200_common *priv,
+			     bool enable)
+{
+	bh_printk(KERN_DEBUG "[BH] Powerave is %s.\n",
+			enable ? "enabled" : "disabled");
+	priv->powersave_enabled = enable;
+}
+
 static int cw1200_bh(void *arg)
 {
 	struct cw1200_common *priv = arg;
@@ -191,18 +227,37 @@ static int cw1200_bh(void *arg)
 	int rx_resync = 1;
 	u16 ctrl_reg = 0;
 	int tx_allowed;
+	int pending_tx = 0;
+	long status;
 
 	for (;;) {
-		int status = wait_event_interruptible(priv->bh_wq, ({
+		if (!priv->hw_bufs_used
+				&& priv->powersave_enabled
+				&& !priv->device_can_sleep)
+			status = 1 * HZ;
+		else
+			status = MAX_SCHEDULE_TIMEOUT;
+
+		status = wait_event_interruptible_timeout(priv->bh_wq, ({
 				rx = atomic_xchg(&priv->bh_rx, 0);
 				tx = atomic_xchg(&priv->bh_tx, 0);
 				term = atomic_xchg(&priv->bh_term, 0);
 				(rx || tx || term);
-			}));
+			}), status);
 
-		if (status || term)
+		if (status < 0 || term)
 			break;
 
+		if (!status) {
+			bh_printk(KERN_DEBUG "[BH] Device wakedown.\n");
+			WARN_ON(cw1200_reg_write_16(priv, ST90TDS_CONTROL_REG_ID, 0));
+			priv->device_can_sleep = true;
+			continue;
+		}
+
+		tx += pending_tx;
+		pending_tx = 0;
+
 		if (rx) {
 			size_t alloc_len;
 			u8 *data;
@@ -211,7 +266,7 @@ static int cw1200_bh(void *arg)
 					priv, &ctrl_reg)))
 				break;
 rx:
-			read_len = (ctrl_reg & 0xFFF) * 2;
+			read_len = (ctrl_reg & ST90TDS_CONT_NEXT_LEN_MASK) * 2;
 			if (!read_len)
 				goto tx;
 
@@ -327,6 +382,19 @@ tx:
 			u8 *data;
 			int ret;
 
+	                if (priv->device_can_sleep) {
+				ret = cw1200_device_wakeup(priv);
+				if (WARN_ON(ret < 0))
+					break;
+				else if (ret)
+					priv->device_can_sleep = false;
+				else {
+					/* Wait for "awake" interrupt */
+					pending_tx = tx;
+					continue;
+				}
+			}
+
 			wsm_alloc_tx_buffer(priv);
 			ret = wsm_get_tx(priv, &data, &tx_len);
 			if (ret <= 0) {
@@ -381,13 +449,13 @@ tx:
 
 		/* HACK!!! Device tends not to send interrupt
 		 * if this extra check is missing */
-		if (!(ctrl_reg & 0xFFF)) {
+		if (!(ctrl_reg & ST90TDS_CONT_NEXT_LEN_MASK)) {
 			if (WARN_ON(cw1200_bh_read_ctrl_reg(
 					priv, &ctrl_reg)))
 				break;
 		}
 
-		if (ctrl_reg & 0xFFF)
+		if (ctrl_reg & ST90TDS_CONT_NEXT_LEN_MASK)
 			goto rx;
 	}