Re: [PATCH v3 3/8] of/address: Introduce of_dma_get_max_cpu_address()

Christoph Hellwig
2020-10-15T05:42:53Z

> +phys_addr_t __init of_dma_get_max_cpu_address(struct device_node *np)
> +{
> + phys_addr_t max_cpu_addr = PHYS_ADDR_MAX;
> + struct of_range_parser parser;
> + phys_addr_t subtree_max_addr;
> + struct device_node *child;
> + phys_addr_t cpu_end = 0;
> + struct of_range range;
> + const __be32 *ranges;
> + int len;
> +
> + if (!np)
> + np = of_root;

Requiring of_root to be passed explicitly would seem more natural
to me than the magic NULL argument. There doesn't seem to be any
precedent for that kind of calling convention either.