4.14-stable review patch. If anyone has any objections, please let me know.
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From: Peter Rosin peda@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 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 --- drivers/mtd/nand/atmel/nand-controller.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-)
--- 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(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);