[PATCH for-5.3] drm/omap: ensure we have a valid dma_mask

[Peter Ujfalusi]

On 09/08/2019 13.00, Tomi Valkeinen wrote:
> Here's my version.
> 
> From c258309e36fc86076db155aead03a3900b96c3d4 Mon Sep 17 00:00:00 2001
> From: Tomi Valkeinen <tomi.valkeinen at ti.com>
> Date: Fri, 9 Aug 2019 09:54:49 +0300
> Subject: [PATCH] drm/omap: ensure we have a valid dma_mask
> 
> The omapdrm driver uses dma_set_coherent_mask(), but that's not enough
> anymore when LPAE is enabled.
> 
> From Christoph Hellwig <hch at lst.de>:
> 
> The traditional arm DMA code ignores, but the generic dma-direct/swiotlb
> has stricter checks and thus fails mappings without a DMA mask.  As we
> use swiotlb for arm with LPAE now, omapdrm needs to catch up and
> actually set a DMA mask.
> 
> Change the dma_set_coherent_mask() call to
> dma_coerce_mask_and_coherent() so that the dev->dma_mask is also set.

Reviewed-by: Peter Ujfalusi <peter.ujfalusi at ti.com>

> Fixes: ad3c7b18c5b3 ("arm: use swiotlb for bounce buffering on LPAE configs")
> Reported-by: "H. Nikolaus Schaller" <hns at goldelico.com>
> Signed-off-by: Tomi Valkeinen <tomi.valkeinen at ti.com>
> 
> diff --git a/drivers/gpu/drm/omapdrm/omap_drv.c b/drivers/gpu/drm/omapdrm/omap_drv.c
> index 288c59dae56a..1bad0a2cc5c6 100644
> --- a/drivers/gpu/drm/omapdrm/omap_drv.c
> +++ b/drivers/gpu/drm/omapdrm/omap_drv.c
> @@ -669,7 +669,7 @@ static int pdev_probe(struct platform_device *pdev)
>  	if (omapdss_is_initialized() == false)
>  		return -EPROBE_DEFER;
>  
> -	ret = dma_set_coherent_mask(&pdev->dev, DMA_BIT_MASK(32));
> +	ret = dma_coerce_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(32));
>  	if (ret) {
>  		dev_err(&pdev->dev, "Failed to set the DMA mask\n");
>  		return ret;
> 
> 
> 
> 

- Péter

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