Patch "spi: rockchip: Signal unfinished DMA transfers" has been added to the 4.6-stable tree

This is a note to let you know that I've just added the patch titled

spi: rockchip: Signal unfinished DMA transfers

to the 4.6-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
spi-rockchip-signal-unfinished-dma-transfers.patch
and it can be found in the queue-4.6 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Tomeu Vizoso <[email protected]>
Date: Wed, 8 Jun 2016 09:32:51 +0200
Subject: spi: rockchip: Signal unfinished DMA transfers

From: Tomeu Vizoso <[email protected]>

commit 4dc0dd83603f05dc3ae152af33ecb15104c313f3 upstream.

When using DMA, the transfer_one callback should return 1 because the transfer hasn't finished yet.

A previous commit changed the function to return 0 when the DMA channels were correctly prepared.

This manifested in Veyron boards with this message:

[ 1.983605] cros-ec-spi spi0.0: EC failed to respond in time

---
 drivers/spi/spi-rockchip.c |    4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

@@ -578,7 +578,7 @@ static int rockchip_spi_transfer_one(
 		struct spi_device *spi,
 		struct spi_transfer *xfer)
 {
-	int ret = 1;
+	int ret = 0;
 	struct rockchip_spi *rs = spi_master_get_devdata(master);
 
 	WARN_ON(readl_relaxed(rs->regs + ROCKCHIP_SPI_SSIENR) &&

@@ -627,6 +627,8 @@ static int rockchip_spi_transfer_one(
 			spi_enable_chip(rs, 1);
 			ret = rockchip_spi_prepare_dma(rs);
 		}
+		/* successful DMA prepare means the transfer is in progress */
+		ret = ret ? ret : 1;
 	} else {
 		spi_enable_chip(rs, 1);
 		ret = rockchip_spi_pio_transfer(rs);

Patches currently in stable-queue which might be from [email protected] are

queue-4.6/spi-rockchip-signal-unfinished-dma-transfers.patch