[v1] of: calculate masks of the device based on dma-range size

This patch update of_dma_configure() API to calculate the
masks (dma_mask and coherent_dma_mask) based on the dma-range
values set in DT for the device. Also limit the mask to lower
of the default mask and mask calculated.

Cc: Joerg Roedel <joro@8bytes.org>
Cc: Grant Likely <grant.likely@linaro.org>
Cc: Rob Herring <robh+dt@kernel.org>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Suravee Suthikulpanit <Suravee.Suthikulpanit@amd.com>

Signed-off-by: Murali Karicheri <m-karicheri2@ti.com>
---
 - apply on top of the series "[PATCH v6 0/7] PCI: get DMA configuration
   from parent device" at www.spinics.net/lists/linux-pci/msg38699.html

 v1 - updated based on comments. Reverted to original
      code for of_dma_get_range() within the of_dma_configure()

 drivers/of/device.c |   21 ++++++++++++++++++---
 1 file changed, 18 insertions(+), 3 deletions(-)

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>
--
To unsubscribe from this list: send the line "unsubscribe linux-pci" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html