Re: [PATCH v2] of/device: Update dma_range_map only when dev has valid dma-ranges

Paul Kocialkowski
2021-01-27T13:04:49Z

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Hi,

On Tue 19 Jan 21, 18:52, Yong Wu wrote:
> The commit e0d072782c73 ("dma-mapping: introduce DMA range map,
> supplanting dma_pfn_offset") always update dma_range_map even though it was
> already set, like in the sunxi_mbus driver. the issue is reported at [1].
> This patch avoid this(Updating it only when dev has valid dma-ranges).
>
> Meanwhile, dma_range_map contains the devices' dma_ranges information,
> This patch moves dma_range_map before of_iommu_configure. The iommu
> driver may need to know the dma_address requirements of its iommu
> consumer devices.

Just a gentle ping on this issue, it would be nice to have this fix merged
ASAP, in the next RC :)

Cheers,

Paul

> [1] https://lore.kernel.org/linux-arm-kernel/5c7946f3-b56e-da00-a750-be097c7ceb32@arm.com/
>
> CC: Rob Herring <robh+dt@kernel.org>
> CC: Frank Rowand <frowand.list@gmail.com>
> Fixes: e0d072782c73 ("dma-mapping: introduce DMA range map, supplanting dma_pfn_offset"),
> Suggested-by: Robin Murphy <robin.murphy@arm.com>
> Signed-off-by: Yong Wu <yong.wu@mediatek.com>
> Signed-off-by: Paul Kocialkowski <paul.kocialkowski@bootlin.com>
> Reviewed-by: Rob Herring <robh@kernel.org>
> ---
> drivers/of/device.c | 10 +++++++---
> 1 file changed, 7 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/of/device.c b/drivers/of/device.c
> index aedfaaafd3e7..1122daa8e273 100644
> --- a/drivers/of/device.c
> +++ b/drivers/of/device.c
> @@ -162,9 +162,11 @@ int of_dma_configure_id(struct device *dev, struct device_node *np,
> mask = DMA_BIT_MASK(ilog2(end) + 1);
> dev->coherent_dma_mask &= mask;
> *dev->dma_mask &= mask;
> - /* ...but only set bus limit if we found valid dma-ranges earlier */
> - if (!ret)
> + /* ...but only set bus limit and range map if we found valid dma-ranges earlier */
> + if (!ret) {
> dev->bus_dma_limit = end;
> + dev->dma_range_map = map;
> + }
>
> coherent = of_dma_is_coherent(np);
> dev_dbg(dev, "device is%sdma coherent\n",
> @@ -172,6 +174,9 @@ int of_dma_configure_id(struct device *dev, struct device_node *np,
>
> iommu = of_iommu_configure(dev, np, id);
> if (PTR_ERR(iommu) == -EPROBE_DEFER) {
> + /* Don't touch range map if it wasn't set from a valid dma-ranges */
> + if (!ret)
> + dev->dma_range_map = NULL;
> kfree(map);
> return -EPROBE_DEFER;
> }
> @@ -181,7 +186,6 @@ int of_dma_configure_id(struct device *dev, struct device_node *np,
>
> arch_setup_dma_ops(dev, dma_start, size, iommu, coherent);
>
> - dev->dma_range_map = map;
> return 0;
> }
> EXPORT_SYMBOL_GPL(of_dma_configure_id);
> --
> 2.18.0
>

--
Paul Kocialkowski, Bootlin
Embedded Linux and kernel engineering
https://bootlin.com

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