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SubjectRe: [PATCH v1] of: calculate masks of the device based on dma-range size
On Wed, Feb 11, 2015 at 12:53:35PM -0500, Murali Karicheri wrote:
> diff --git a/drivers/of/device.c b/drivers/of/device.c
> index 314c8a9..167ad2d 100644
> --- a/drivers/of/device.c
> +++ b/drivers/of/device.c
> @@ -90,10 +90,11 @@ void of_dma_configure(struct device *dev, struct device_node *np)
> struct iommu_ops *iommu;
>
> /*
> - * Set default dma-mask to 32 bit. Drivers are expected to setup
> - * the correct supported dma_mask.
> + * Set default coherent_dma_mask to 32 bit. Drivers are expected to
> + * setup the correct supported mask.
> */
> - dev->coherent_dma_mask = DMA_BIT_MASK(32);
> + if (!dev->coherent_dma_mask)
> + dev->coherent_dma_mask = DMA_BIT_MASK(32);
>
> /*
> * Set it to coherent_dma_mask by default if the architecture
> @@ -102,6 +103,11 @@ void of_dma_configure(struct device *dev, struct device_node *np)
> if (!dev->dma_mask)
> dev->dma_mask = &dev->coherent_dma_mask;
>
> + /*
> + * Use default size to cover 32 bit. Drivers need to set this in DT
> + * to override the same.
> + */
> + size = 1ULL << 32;

I'm not sure this is needed since on error path the original code would
set the size to coherent_dma_mask.

> ret = of_dma_get_range(np, &dma_addr, &paddr, &size);
> if (ret < 0) {
> dma_addr = offset = 0;

Here we already have (not seen in the context):

size = dev->coherent_dma_mask + 1;

> @@ -128,6 +134,15 @@ void of_dma_configure(struct device *dev, struct device_node *np)
>
> dev->dma_pfn_offset = offset;
>
> + /*
> + * Limit coherent and dma mask based on size and default mask
> + * set by the driver.
> + */
> + dev->coherent_dma_mask = min(dev->coherent_dma_mask,
> + DMA_BIT_MASK(ilog2(dma_addr + size)));
> + *dev->dma_mask = min((*dev->dma_mask),
> + DMA_BIT_MASK(ilog2(dma_addr + size)));
> +
> coherent = of_dma_is_coherent(np);
> dev_dbg(dev, "device is%sdma coherent\n",
> coherent ? " " : " not ");

Otherwise it looks fine to me.

Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>


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