Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit be6893e1 authored by Laurent Pinchart's avatar Laurent Pinchart Committed by Vinod Koul
Browse files

dmaengine: rcar-dmac: Disable channel 0 when using IOMMU 



A still unconfirmed hardware bug prevents the IPMMU microTLB 0 to be
flushed correctly, resulting in memory corruption. DMAC 0 channel 0 is
connected to microTLB 0 on currently supported platforms, so we can't
use it with the IPMMU. As the IOMMU API operates at the device level we
can't disable it selectively, so ignore channel 0 for now if the device
is part of an IOMMU group.

Signed-off-by: default avatarLaurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Acked-by: default avatarGeert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: default avatarVinod Koul <vinod.koul@intel.com>
parent 3f463061

drivers/dma/sh/rcar-dmac.c

+16 −1
Original line number Diff line number Diff line
@@ -1593,6 +1593,7 @@ static int rcar_dmac_probe(struct platform_device *pdev) 
		DMA_SLAVE_BUSWIDTH_2_BYTES | DMA_SLAVE_BUSWIDTH_4_BYTES |

		DMA_SLAVE_BUSWIDTH_8_BYTES | DMA_SLAVE_BUSWIDTH_16_BYTES |

		DMA_SLAVE_BUSWIDTH_32_BYTES | DMA_SLAVE_BUSWIDTH_64_BYTES;

	unsigned int channels_offset = 0;

	struct dma_device *engine;

	struct rcar_dmac *dmac;

	struct resource *mem;
@@ -1612,6 +1613,19 @@ static int rcar_dmac_probe(struct platform_device *pdev) 
	if (ret < 0)

		return ret;



	/*

	 * A still unconfirmed hardware bug prevents the IPMMU microTLB 0 to be

	 * flushed correctly, resulting in memory corruption. DMAC 0 channel 0

	 * is connected to microTLB 0 on currently supported platforms, so we

	 * can't use it with the IPMMU. As the IOMMU API operates at the device

	 * level we can't disable it selectively, so ignore channel 0 for now if

	 * the device is part of an IOMMU group.

	 */

	if (pdev->dev.iommu_group) {

		dmac->n_channels--;

		channels_offset = 1;

	}



	dmac->channels = devm_kcalloc(&pdev->dev, dmac->n_channels,

				      sizeof(*dmac->channels), GFP_KERNEL);

	if (!dmac->channels)
@@ -1662,7 +1676,8 @@ static int rcar_dmac_probe(struct platform_device *pdev) 
	INIT_LIST_HEAD(&dmac->engine.channels);



	for (i = 0; i < dmac->n_channels; ++i) {

		ret = rcar_dmac_chan_probe(dmac, &dmac->channels[i], i);

		ret = rcar_dmac_chan_probe(dmac, &dmac->channels[i],

					   i + channels_offset);

		if (ret < 0)

			goto error;

	}