Re: [RFC PATCH v3 2/6] swiotlb: Add restricted DMA pool

[Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>]

Hello!

In this file:

> diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c
> index e4368159f88a..7fb2ac087d23 100644
> --- a/kernel/dma/swiotlb.c
> +++ b/kernel/dma/swiotlb.c
..

> +static const struct reserved_mem_ops rmem_swiotlb_ops = {
> +     .device_init    = rmem_swiotlb_device_init,
> +     .device_release = rmem_swiotlb_device_release,
> +};
> +
> +static int __init rmem_swiotlb_setup(struct reserved_mem *rmem)
> +{
> +     unsigned long node = rmem->fdt_node;
> +
> +     if (of_get_flat_dt_prop(node, "reusable", NULL) ||
> +         of_get_flat_dt_prop(node, "linux,cma-default", NULL) ||
> +         of_get_flat_dt_prop(node, "linux,dma-default", NULL) ||
> +         of_get_flat_dt_prop(node, "no-map", NULL))
> +             return -EINVAL;
> +
> +     rmem->ops = &rmem_swiotlb_ops;
> +     pr_info("Reserved memory: created device swiotlb memory pool at %pa, 
> size %ld MiB\n",
> +             &rmem->base, (unsigned long)rmem->size / SZ_1M);
> +     return 0;
> +}
> +
> +RESERVEDMEM_OF_DECLARE(dma, "restricted-dma-pool", rmem_swiotlb_setup);

The code should be as much as possible arch-agnostic. That is why there
are multiple -swiotlb files scattered in arch directories that own the
architecture specific code.

Would it be possible to move the code there and perhaps have a ARM
specific front-end for this DMA restricted pool there? See for example
the xen-swiotlb code.

Cheers!

Konrad