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Patch "spi: rockchip: modify DMA max burst to 1" has been added to the 4.4-stable tree

PATCH [email protected] 1 participant 1 message May 2, 2016

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Stable branch SPI Arm Rockchip
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This is a note to let you know that I've just added the patch titled

spi: rockchip: modify DMA max burst to 1

to the 4.4-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-modify-dma-max-burst-to-1.patch
and it can be found in the queue-4.4 subdirectory.

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

Quoted 1 line

From 80abf8880cc6e1594c11b7c417f22dde60e25312 Mon Sep 17 00:00:00 2001

From: Addy Ke <[email protected]>
Date: Fri, 22 Jan 2016 19:06:52 +0800
Subject: spi: rockchip: modify DMA max burst to 1

From: Addy Ke <[email protected]>

commit 80abf8880cc6e1594c11b7c417f22dde60e25312 upstream.

Generic dma controller on Rockchips' platform cannot support DMAFLUSHP instruction which make dma to flush the req of non-aligned or non-multiple of what we need. That will cause an unrecoverable dma bus error. The saftest way is to set dma max burst to 1.

Signed-off-by Addy ke <[email protected]>
Fixes 64e36824b32b06 ("spi/rockchip: add driver for Rockchip...")
Signed-off-by Shawn Lin <[email protected]>
cc Heiko Stuebner <[email protected]>
cc Olof Johansson <[email protected]>
cc Doug Anderson <[email protected]>
cc Sonny Rao <[email protected]>
Acked-by Mark Brown <[email protected]>
Signed-off-by Caesar Wang <[email protected]>
Signed-off-by Vinod Koul <[email protected]>
Signed-off-by Greg Kroah-Hartman <[email protected]>
---
 drivers/spi/spi-rockchip.c |   12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)
drivers/spi/spi-rockchip.c +10 -2
@@ -199,6 +199,7 @@ struct rockchip_spi {
 	struct sg_table rx_sg;
 	struct rockchip_spi_dma_data dma_rx;
 	struct rockchip_spi_dma_data dma_tx;
+	struct dma_slave_caps dma_caps;
 };
 
 static inline void spi_enable_chip(struct rockchip_spi *rs, int enable)

@@ -454,7 +455,10 @@ static void rockchip_spi_prepare_dma(str
 		rxconf.direction = rs->dma_rx.direction;
 		rxconf.src_addr = rs->dma_rx.addr;
 		rxconf.src_addr_width = rs->n_bytes;
-		rxconf.src_maxburst = rs->n_bytes;
+		if (rs->dma_caps.max_burst > 4)
+			rxconf.src_maxburst = 4;
+		else
+			rxconf.src_maxburst = 1;
 		dmaengine_slave_config(rs->dma_rx.ch, &rxconf);
 
 		rxdesc = dmaengine_prep_slave_sg(

@@ -471,7 +475,10 @@ static void rockchip_spi_prepare_dma(str
 		txconf.direction = rs->dma_tx.direction;
 		txconf.dst_addr = rs->dma_tx.addr;
 		txconf.dst_addr_width = rs->n_bytes;
-		txconf.dst_maxburst = rs->n_bytes;
+		if (rs->dma_caps.max_burst > 4)
+			txconf.dst_maxburst = 4;
+		else
+			txconf.dst_maxburst = 1;
 		dmaengine_slave_config(rs->dma_tx.ch, &txconf);
 
 		txdesc = dmaengine_prep_slave_sg(

@@ -735,6 +742,7 @@ static int rockchip_spi_probe(struct pla
 	}
 
 	if (rs->dma_tx.ch && rs->dma_rx.ch) {
+		dma_get_slave_caps(rs->dma_rx.ch, &(rs->dma_caps));
 		rs->dma_tx.addr = (dma_addr_t)(mem->start + ROCKCHIP_SPI_TXDR);
 		rs->dma_rx.addr = (dma_addr_t)(mem->start + ROCKCHIP_SPI_RXDR);
 		rs->dma_tx.direction = DMA_MEM_TO_DEV;

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

queue-4.4/spi-rockchip-modify-dma-max-burst-to-1.patch