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[4.2.y-ckt,stable] Patch "spi: rockchip: modify DMA max burst to 1" has been added to the 4.2.y-ckt tree

Message ID 1459382060-7489-1-git-send-email-kamal@canonical.com
State New
Headers show

Commit Message

Kamal Mostafa March 30, 2016, 11:54 p.m. UTC 
This is a note to let you know that I have just added a patch titled

    spi: rockchip: modify DMA max burst to 1

to the linux-4.2.y-queue branch of the 4.2.y-ckt extended stable tree 
which can be found at:

    http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-4.2.y-queue

This patch is scheduled to be released in version 4.2.8-ckt7.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 4.2.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Kamal

---8<------------------------------------------------------------

From da1f4dff512788c486c79e8877857134aae87a68 Mon Sep 17 00:00:00 2001
From: Addy Ke <addy.ke@rock-chips.com>
Date: Fri, 22 Jan 2016 19:06:52 +0800
Subject: spi: rockchip: modify DMA max burst to 1

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 <addy.ke@rock-chips.com>
Fixes: 64e36824b32b06 ("spi/rockchip: add driver for Rockchip...")
Signed-off-by: Shawn Lin <shawn.lin@rock-chips.com>
cc: Heiko Stuebner <heiko@sntech.de>
cc: Olof Johansson <olof@lixom.net>
cc: Doug Anderson <dianders@chromium.org>
cc: Sonny Rao <sonnyrao@chromium.org>

Acked-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Caesar Wang <wxt@rock-chips.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
---
 drivers/spi/spi-rockchip.c | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

--
2.7.4
diff mbox

Patch

diff --git a/drivers/spi/spi-rockchip.c b/drivers/spi/spi-rockchip.c
index 68e7efe..2fed713 100644
--- a/drivers/spi/spi-rockchip.c
+++ b/drivers/spi/spi-rockchip.c
@@ -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)
@@ -449,7 +450,10 @@  static void rockchip_spi_prepare_dma(struct rockchip_spi *rs)
 		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(
@@ -466,7 +470,10 @@  static void rockchip_spi_prepare_dma(struct rockchip_spi *rs)
 		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(
@@ -731,6 +738,7 @@  static int rockchip_spi_probe(struct platform_device *pdev)
 	}

 	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;