---

yaml
---
r: 280112
b: refs/heads/master
c: 8b8d719
h: refs/heads/master
v: v3

[refs]

@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 53e4acea0e819a6a8513e10a0773f2259ede0481
+refs/heads/master: 8b8d719161c386668161daf29b2632f094e326c8

trunk/drivers/spi/spi-pl022.c

@@ -340,6 +340,10 @@ struct vendor_data {
  * @cur_msg: Pointer to current spi_message being processed
  * @cur_transfer: Pointer to current spi_transfer
  * @cur_chip: pointer to current clients chip(assigned from controller_state)
+ * @next_msg_cs_active: the next message in the queue has been examined
+ *  and it was found that it uses the same chip select as the previous
+ *  message, so we left it active after the previous transfer, and it's
+ *  active already.
  * @tx: current position in TX buffer to be read
  * @tx_end: end position in TX buffer to be read
  * @rx: current position in RX buffer to be written
@@ -373,6 +377,7 @@ struct pl022 {
 	struct spi_message		*cur_msg;
 	struct spi_transfer		*cur_transfer;
 	struct chip_data		*cur_chip;
+	bool				next_msg_cs_active;
 	void				*tx;
 	void				*tx_end;
 	void				*rx;
@@ -445,23 +450,9 @@ static void giveback(struct pl022 *pl022)
 	struct spi_transfer *last_transfer;
 	unsigned long flags;
 	struct spi_message *msg;
-	void (*curr_cs_control) (u32 command);
+	pl022->next_msg_cs_active = false;
 
-	/*
-	 * This local reference to the chip select function
-	 * is needed because we set curr_chip to NULL
-	 * as a step toward termininating the message.
-	 */
-	curr_cs_control = pl022->cur_chip->cs_control;
-	spin_lock_irqsave(&pl022->queue_lock, flags);
-	msg = pl022->cur_msg;
-	pl022->cur_msg = NULL;
-	pl022->cur_transfer = NULL;
-	pl022->cur_chip = NULL;
-	queue_work(pl022->workqueue, &pl022->pump_messages);
-	spin_unlock_irqrestore(&pl022->queue_lock, flags);
-
-	last_transfer = list_entry(msg->transfers.prev,
+	last_transfer = list_entry(pl022->cur_msg->transfers.prev,
 					struct spi_transfer,
 					transfer_list);
 
@@ -473,18 +464,13 @@ static void giveback(struct pl022 *pl022)
 		 */
 		udelay(last_transfer->delay_usecs);
 
-	/*
-	 * Drop chip select UNLESS cs_change is true or we are returning
-	 * a message with an error, or next message is for another chip
-	 */
-	if (!last_transfer->cs_change)
-		curr_cs_control(SSP_CHIP_DESELECT);
-	else {
+	if (!last_transfer->cs_change) {
 		struct spi_message *next_msg;
 
-		/* Holding of cs was hinted, but we need to make sure
-		 * the next message is for the same chip.  Don't waste
-		 * time with the following tests unless this was hinted.
+		/*
+		 * cs_change was not set. We can keep the chip select
+		 * enabled if there is message in the queue and it is
+		 * for the same spi device.
 		 *
 		 * We cannot postpone this until pump_messages, because
 		 * after calling msg->complete (below) the driver that
@@ -501,14 +487,26 @@ static void giveback(struct pl022 *pl022)
 					struct spi_message, queue);
 		spin_unlock_irqrestore(&pl022->queue_lock, flags);
 
-		/* see if the next and current messages point
-		 * to the same chip
+		/*
+		 * see if the next and current messages point
+		 * to the same spi device.
 		 */
-		if (next_msg && next_msg->spi != msg->spi)
+		if (next_msg && next_msg->spi != pl022->cur_msg->spi)
 			next_msg = NULL;
-		if (!next_msg || msg->state == STATE_ERROR)
-			curr_cs_control(SSP_CHIP_DESELECT);
+		if (!next_msg || pl022->cur_msg->state == STATE_ERROR)
+			pl022->cur_chip->cs_control(SSP_CHIP_DESELECT);
+		else
+			pl022->next_msg_cs_active = true;
 	}
+
+	spin_lock_irqsave(&pl022->queue_lock, flags);
+	msg = pl022->cur_msg;
+	pl022->cur_msg = NULL;
+	pl022->cur_transfer = NULL;
+	pl022->cur_chip = NULL;
+	queue_work(pl022->workqueue, &pl022->pump_messages);
+	spin_unlock_irqrestore(&pl022->queue_lock, flags);
+
 	msg->state = NULL;
 	if (msg->complete)
 		msg->complete(msg->context);
@@ -1350,7 +1348,7 @@ static void pump_transfers(unsigned long data)
 			 */
 			udelay(previous->delay_usecs);
 
-		/* Drop chip select only if cs_change is requested */
+		/* Reselect chip select only if cs_change was requested */
 		if (previous->cs_change)
 			pl022->cur_chip->cs_control(SSP_CHIP_SELECT);
 	} else {
@@ -1389,8 +1387,10 @@ static void do_interrupt_dma_transfer(struct pl022 *pl022)
 	 */
 	u32 irqflags = ENABLE_ALL_INTERRUPTS & ~SSP_IMSC_MASK_RXIM;
 
-	/* Enable target chip */
-	pl022->cur_chip->cs_control(SSP_CHIP_SELECT);
+	/* Enable target chip, if not already active */
+	if (!pl022->next_msg_cs_active)
+		pl022->cur_chip->cs_control(SSP_CHIP_SELECT);
+
 	if (set_up_next_transfer(pl022, pl022->cur_transfer)) {
 		/* Error path */
 		pl022->cur_msg->state = STATE_ERROR;
@@ -1445,7 +1445,8 @@ static void do_polling_transfer(struct pl022 *pl022)
 		} else {
 			/* STATE_START */
 			message->state = STATE_RUNNING;
-			pl022->cur_chip->cs_control(SSP_CHIP_SELECT);
+			if (!pl022->next_msg_cs_active)
+				pl022->cur_chip->cs_control(SSP_CHIP_SELECT);
 		}
 
 		/* Configuration Changing Per Transfer */
@@ -1604,6 +1605,7 @@ static int start_queue(struct pl022 *pl022)
 	pl022->cur_msg = NULL;
 	pl022->cur_transfer = NULL;
 	pl022->cur_chip = NULL;
+	pl022->next_msg_cs_active = false;
 	spin_unlock_irqrestore(&pl022->queue_lock, flags);
 
 	queue_work(pl022->workqueue, &pl022->pump_messages);