4.18-stable review patch. If anyone has any objections, please let me know.
------------------
From: Peter Rosin <p...@axentia.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 <p...@axentia.se>
Reviewed-by: Boris Brezillon <boris.brezil...@bootlin.com>
Signed-off-by: Miquel Raynal <miquel.ray...@bootlin.com>
Signed-off-by: Sasha Levin <alexander.le...@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>
---
drivers/mtd/nand/raw/atmel/nand-controller.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)
--- a/drivers/mtd/nand/raw/atmel/nand-controller.c
+++ b/drivers/mtd/nand/raw/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,
@@ -1977,7 +1982,7 @@ static int atmel_nand_controller_init(st
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);
