Hello!

In this file:

..

+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