Commit 8cbb2f74 authored Mar 29, 2018 by Peter Rosin Committed by Greg Kroah-Hartman Oct 03, 2018

mtd: rawnand: atmel: add module param to avoid using dma



[ 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@axentia.se>
Reviewed-by: Boris Brezillon <boris.brezillon@bootlin.com>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

parent a838008b

drivers/mtd/nand/atmel/nand-controller.c

+6 −1

Original line number	Diff line number	Diff line
		@@ -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);