Commit f83a6e5d authored by Maxime Ripard's avatar Maxime Ripard Committed by Rob Herring
Browse files

of: address: Add support for the parent DMA bus 



Some SoCs have devices that are using a separate bus from the main bus to
perform DMA.

These buses might have some restrictions and/or different mapping than from
the CPU side, so we'd need to express those using the usual dma-ranges, but
using a different DT node than the node's parent.

Now that the generic interconnect bindings are available, we can model an
interconnect with the reserved name "dma-mem" for those use-cases.

Reviewed-by: default avatarRobin Murphy <robin.murphy@arm.com>
Signed-off-by: default avatarMaxime Ripard <maxime.ripard@bootlin.com>
Signed-off-by: default avatarRob Herring <robh@kernel.org>
parent 95835a8d

drivers/of/address.c

+26 −2
Original line number Diff line number Diff line
@@ -677,12 +677,30 @@ u64 of_translate_address(struct device_node *dev, const __be32 *in_addr) 
}

EXPORT_SYMBOL(of_translate_address);



static struct device_node *__of_get_dma_parent(const struct device_node *np)

{

	struct of_phandle_args args;

	int ret, index;



	index = of_property_match_string(np, "interconnect-names", "dma-mem");

	if (index < 0)

		return of_get_parent(np);



	ret = of_parse_phandle_with_args(np, "interconnects",

					 "#interconnect-cells",

					 index, &args);

	if (ret < 0)

		return of_get_parent(np);



	return of_node_get(args.np);

}



u64 of_translate_dma_address(struct device_node *dev, const __be32 *in_addr)

{

	struct device_node *host;

	u64 ret;



	ret = __of_translate_address(dev, of_get_parent,

	ret = __of_translate_address(dev, __of_get_dma_parent,

				     in_addr, "dma-ranges", &host);



	if (host) {
@@ -912,9 +930,15 @@ int of_dma_get_range(struct device_node *np, u64 *dma_addr, u64 *paddr, u64 *siz 
		return -EINVAL;



	while (1) {

		struct device_node *parent;



		naddr = of_n_addr_cells(node);

		nsize = of_n_size_cells(node);

		node = of_get_next_parent(node);



		parent = __of_get_dma_parent(node);

		of_node_put(node);



		node = parent;

		if (!node)

			break;

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