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

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>
This commit is contained in:
Peter Rosin 2018-03-29 15:10:54 +02:00 committed by Miquel Raynal
parent 021c91791a
commit efc6362c6f
1 changed files with 6 additions and 1 deletions
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7
drivers/mtd/nand/raw/atmel/nand-controller.c
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@ -129,6 +129,11 @@
#define DEFAULT_TIMEOUT_MS 1000 #define DEFAULT_TIMEOUT_MS 1000
#define MIN_DMA_LEN 128 #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 { enum atmel_nand_rb_type {
ATMEL_NAND_NO_RB, ATMEL_NAND_NO_RB,
ATMEL_NAND_NATIVE_RB, ATMEL_NAND_NATIVE_RB,
@ -1977,7 +1982,7 @@ static int atmel_nand_controller_init(struct atmel_nand_controller *nc,
return ret; return ret;
} }
if (nc->caps->has_dma) { if (nc->caps->has_dma && !atmel_nand_avoid_dma) {
dma_cap_mask_t mask; dma_cap_mask_t mask;
dma_cap_zero(mask); dma_cap_zero(mask);