Commit f5be833d authored by Michael Walle's avatar Michael Walle Committed by Lucas Stach
Browse files

drm/etnaviv: use a 32 bit mask as coherent DMA mask 



The STLB and the first command buffer (which is used to set up the TLBs)
has a 32 bit size restriction in hardware. There seems to be no way to
specify addresses larger than 32 bit. Keep it simple and restict the
addresses to the lower 4 GiB range for all coherent DMA memory
allocations.

Please note, that platform_device_alloc() will initialize dev->dma_mask
to point to pdev->platform_dma_mask, thus dma_set_mask() will work as
expected.

While at it, move the dma_mask setup code to the of_dma_configure() to
keep all the DMA setup code next to each other.

Suggested-by: default avatarLucas Stach <l.stach@pengutronix.de>
Signed-off-by: default avatarMichael Walle <michael@walle.cc>
Signed-off-by: default avatarLucas Stach <l.stach@pengutronix.de>
parent 0ea057a9

drivers/gpu/drm/etnaviv/etnaviv_drv.c

+18 −2
Original line number Diff line number Diff line
@@ -613,6 +613,24 @@ static int etnaviv_pdev_probe(struct platform_device *pdev) 
			component_match_add(dev, &match, compare_str, names[i]);

	}



	/*

	 * PTA and MTLB can have 40 bit base addresses, but

	 * unfortunately, an entry in the MTLB can only point to a

	 * 32 bit base address of a STLB. Moreover, to initialize the

	 * MMU we need a command buffer with a 32 bit address because

	 * without an MMU there is only an indentity mapping between

	 * the internal 32 bit addresses and the bus addresses.

	 *

	 * To make things easy, we set the dma_coherent_mask to 32

	 * bit to make sure we are allocating the command buffers and

	 * TLBs in the lower 4 GiB address space.

	 */

	if (dma_set_mask(&pdev->dev, DMA_BIT_MASK(40)) ||

	    dma_set_coherent_mask(&pdev->dev, DMA_BIT_MASK(32))) {

		dev_dbg(&pdev->dev, "No suitable DMA available\n");

		return -ENODEV;

	}



	/*

	 * Apply the same DMA configuration to the virtual etnaviv

	 * device as the GPU we found. This assumes that all Vivante
@@ -671,8 +689,6 @@ static int __init etnaviv_init(void) 
			of_node_put(np);

			goto unregister_platform_driver;

		}

		pdev->dev.coherent_dma_mask = DMA_BIT_MASK(40);

		pdev->dev.dma_mask = &pdev->dev.coherent_dma_mask;



		ret = platform_device_add(pdev);

		if (ret) {