Subject: [PATCH v2 5/5] ACPI/IORT: Add IORT named component memory address limits

From: [email-masked] (Nate Watterson)
Date: Wed, 2 Aug 2017 13:31:03 -0400

Hi Lorenzo,
I ran a quick test and this seems to work for memory_address_limit < 64,
however memory_address_limit == 64 yields a mask of 0x0.

-Nate

On 7/31/2017 11:23 AM, Lorenzo Pieralisi wrote:
> IORT named components provide firmware configuration describing
> how many address bits a given device is capable of generating
> to address memory.
> 
> Add code to the kernel to retrieve memory address limits
> configuration for IORT named components and configure DMA masks
> accordingly.
> 
> Signed-off-by: Lorenzo Pieralisi <[email-masked]>
> Cc: Will Deacon <[email-masked]>
> Cc: Robin Murphy <[email-masked]>
> Cc: Nate Watterson <[email-masked]>
> ---
>   drivers/acpi/arm64/iort.c | 40 ++++++++++++++++++++++++++++++----------
>   1 file changed, 30 insertions(+), 10 deletions(-)
> 
> diff --git a/drivers/acpi/arm64/iort.c b/drivers/acpi/arm64/iort.c
> index 67b85ae..b85d19f 100644
> --- a/drivers/acpi/arm64/iort.c
> +++ b/drivers/acpi/arm64/iort.c
> @@ -680,6 +680,24 @@ static const struct iommu_ops *iort_iommu_xlate(struct device *dev,
>   	return ret ? NULL : ops;
>   }
>   
> +static int nc_dma_get_range(struct device *dev, u64 *size)
> +{
> +	struct acpi_iort_node *node;
> +	struct acpi_iort_named_component *ncomp;
> +
> +	node = iort_scan_node(ACPI_IORT_NODE_NAMED_COMPONENT,
> +			      iort_match_node_callback, dev);
> +	if (!node)
> +		return -ENODEV;
> +
> +	ncomp = (struct acpi_iort_named_component *)node->node_data;
> +
> +	*size = ncomp->memory_address_limit >= 64 ? ~0ULL :
> +			1ULL<<ncomp->memory_address_limit;
> +
> +	return 0;
> +}
> +
>   /**
>    * iort_dma_setup() - Set-up device DMA parameters.
>    *
> @@ -708,17 +726,19 @@ void iort_dma_setup(struct device *dev, u64 *dma_addr, u64 *dma_size)
>   
>   	size = max(dev->coherent_dma_mask, dev->coherent_dma_mask + 1);
>   
> -	if (dev_is_pci(dev)) {
> +	if (dev_is_pci(dev))
>   		ret = acpi_dma_get_range(dev, &dmaaddr, &offset, &size);
> -		if (!ret) {
> -			mask = __roundup_pow_of_two(dmaaddr + size) - 1;
> -			/*
> -			 * Limit coherent and dma mask based on size
> -			 * retrieved from firmware.
> -			 */
> -			dev->coherent_dma_mask = mask;
> -			*dev->dma_mask = mask;
> -		}
> +	else
> +		ret = nc_dma_get_range(dev, &size);
> +
> +	if (!ret) {
> +		mask = __roundup_pow_of_two(dmaaddr + size) - 1;
> +		/*
> +		 * Limit coherent and dma mask based on size
> +		 * retrieved from firmware.
> +		 */
> +		dev->coherent_dma_mask = mask;
> +		*dev->dma_mask = mask;
>   	}
>   
>   	*dma_addr = dmaaddr;
> 

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