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Message-ID: <20180917030220.245686-47-alexander.levin@microsoft.com>
Date: Mon, 17 Sep 2018 03:02:52 +0000
From: Sasha Levin <Alexander.Levin@...rosoft.com>
To: "stable@...r.kernel.org" <stable@...r.kernel.org>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
CC: Peter Rosin <peda@...ntia.se>,
Miquel Raynal <miquel.raynal@...tlin.com>,
Sasha Levin <Alexander.Levin@...rosoft.com>
Subject: [PATCH AUTOSEL 4.14 47/87] mtd: rawnand: atmel: add module param to
avoid using dma
From: Peter Rosin <peda@...ntia.se>
[ Upstream commit efc6362c6f8c1e74b340e2611f1b35e7d557ce7b ]
On a sama5d31 with a Full-HD dual LVDS panel (132MHz pixel clock) NAND
flash accesses have a tendency to cause display disturbances. Add a
module param to disable DMA from the NAND controller, since that fixes
the display problem for me.
Signed-off-by: Peter Rosin <peda@...ntia.se>
Reviewed-by: Boris Brezillon <boris.brezillon@...tlin.com>
Signed-off-by: Miquel Raynal <miquel.raynal@...tlin.com>
Signed-off-by: Sasha Levin <alexander.levin@...rosoft.com>
---
drivers/mtd/nand/atmel/nand-controller.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/drivers/mtd/nand/atmel/nand-controller.c b/drivers/mtd/nand/atmel/nand-controller.c
index 68c9d98a3347..148744418e82 100644
--- a/drivers/mtd/nand/atmel/nand-controller.c
+++ b/drivers/mtd/nand/atmel/nand-controller.c
@@ -129,6 +129,11 @@
#define DEFAULT_TIMEOUT_MS 1000
#define MIN_DMA_LEN 128
+static bool atmel_nand_avoid_dma __read_mostly;
+
+MODULE_PARM_DESC(avoiddma, "Avoid using DMA");
+module_param_named(avoiddma, atmel_nand_avoid_dma, bool, 0400);
+
enum atmel_nand_rb_type {
ATMEL_NAND_NO_RB,
ATMEL_NAND_NATIVE_RB,
@@ -1975,7 +1980,7 @@ static int atmel_nand_controller_init(struct atmel_nand_controller *nc,
return ret;
}
- if (nc->caps->has_dma) {
+ if (nc->caps->has_dma && !atmel_nand_avoid_dma) {
dma_cap_mask_t mask;
dma_cap_zero(mask);
--
2.17.1
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