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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: Lucas Stach <l.stach@pengutronix.de>
Signed-off-by: Michael Walle <michael@walle.cc>
Signed-off-by: Lucas Stach <l.stach@pengutronix.de>
This commit is contained in:
Michael Walle 2021-09-07 18:49:45 +02:00 committed by Lucas Stach
parent 0ea057a9cb
commit f5be833dc8
1 changed files with 18 additions and 2 deletions
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20
drivers/gpu/drm/etnaviv/etnaviv_drv.c
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@ -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) {