[PATCH 4/9] soc: apple: Add SART driver

[Alyssa Rosenzweig]

> +/*
> + * Adds the region [paddr, paddr+size] to the DMA allow list.
> + *
> + * @sart: SART reference
> + * @paddr: Start address of the region to be used for DMA
> + * @size: Size of the region to be used for DMA.
> + */
> +int apple_sart_add_allowed_region(struct apple_sart *sart, phys_addr_t paddr,
> +				  size_t size);
> +
> +/*
> + * Removes the region [paddr, paddr+size] from the DMA allow list.
> + *
> + * Note that exact same paddr and size used for apple_sart_add_allowed_region
> + * have to be passed.
> + *
> + * @sart: SART reference
> + * @paddr: Start address of the region no longer used for DMA
> + * @size: Size of the region no longer used for DMA.
> + */
> +int apple_sart_remove_allowed_region(struct apple_sart *sart, phys_addr_t paddr,
> +				     size_t size);

Might it be simpler for add_allowed_region to return a handle that
remove_allowed_region takes instead of paddr+size? Then
remove_allowed_region doesn't have to walk anything, and the requirement
to use the same paddr/size is implicit.