spi-dw: delete cur_msg when pump message and transfer has finished

From: xiao jin <[email protected]>
Date: Tue, 20 Nov 2012 13:45:47 +0800
Subject: [PATCH] spi-dw: delete cur_msg when pump message and transfer has finished

We see DPM device timeout happened in spi_max3111 when system suspend.

The root cause is related to the time we delete msg from dw_spi queue.

Below is the scenario how timeout happened.
step1, max3110_main_thread pump the dw_spi msg and transfer it. And the msg is deleted from dw_spi queue right now.
step2, runtime suspend happened, there is no msg in the dw_spi queue, it's permitted to enter into D0i3.
step3, After resume from D0i3, irq will not come for ever, max3110_main_thread still wait for the completion of last pump message transfer.
step4, system suspend, serial_m3110_shutdown call max3110_out and try to lock the mutex, but it has been hold and cannot be released by max3110_main_thread for ever.
step5, DPM device timer timeout.

This patch is to delete the cur msg when msg complete.

---
 drivers/spi/spi-dw.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

index d1a495f..f6bf693 100644
@@ -268,6 +268,7 @@ static void giveback(struct dw_spi *dws)
 
 	spin_lock_irqsave(&dws->lock, flags);
 	msg = dws->cur_msg;
+	list_del_init(&dws->cur_msg->queue);
 	dws->cur_msg = NULL;
 	dws->cur_transfer = NULL;
 	dws->prev_chip = dws->cur_chip;

@@ -571,7 +572,6 @@ static void pump_messages(struct work_struct *work)
 
 	/* Extract head of queue */
 	dws->cur_msg = list_entry(dws->queue.next, struct spi_message, queue);
-	list_del_init(&dws->cur_msg->queue);
 
 	/* Initial message state*/
 	dws->cur_msg->state = START_STATE;

1.7.1