Commit 964db79d authored by Nicolas Saenz Julienne's avatar Nicolas Saenz Julienne Committed by Catalin Marinas
Browse files

of/address: Introduce of_dma_get_max_cpu_address() 



Introduce of_dma_get_max_cpu_address(), which provides the highest CPU
physical address addressable by all DMA masters in the system. It's
specially useful for setting memory zones sizes at early boot time.

Signed-off-by: default avatarNicolas Saenz Julienne <nsaenzjulienne@suse.de>
Reviewed-by: default avatarRob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20201119175400.9995-4-nsaenzjulienne@suse.de


Signed-off-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
parent 9804f8c6

drivers/of/address.c

+42 −0
Original line number Diff line number Diff line
@@ -1024,6 +1024,48 @@ int of_dma_get_range(struct device_node *np, const struct bus_dma_region **map) 
}

#endif /* CONFIG_HAS_DMA */



/**

 * of_dma_get_max_cpu_address - Gets highest CPU address suitable for DMA

 * @np: The node to start searching from or NULL to start from the root

 *

 * Gets the highest CPU physical address that is addressable by all DMA masters

 * in the sub-tree pointed by np, or the whole tree if NULL is passed. If no

 * DMA constrained device is found, it returns PHYS_ADDR_MAX.

 */

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;

	struct of_range range;

	const __be32 *ranges;

	u64 cpu_end = 0;

	int len;



	if (!np)

		np = of_root;



	ranges = of_get_property(np, "dma-ranges", &len);

	if (ranges && len) {

		of_dma_range_parser_init(&parser, np);

		for_each_of_range(&parser, &range)

			if (range.cpu_addr + range.size > cpu_end)

				cpu_end = range.cpu_addr + range.size - 1;



		if (max_cpu_addr > cpu_end)

			max_cpu_addr = cpu_end;

	}



	for_each_available_child_of_node(np, child) {

		subtree_max_addr = of_dma_get_max_cpu_address(child);

		if (max_cpu_addr > subtree_max_addr)

			max_cpu_addr = subtree_max_addr;

	}



	return max_cpu_addr;

}



/**

 * of_dma_is_coherent - Check if device is coherent

 * @np:	device node

include/linux/of.h

+7 −0
Original line number Diff line number Diff line
@@ -558,6 +558,8 @@ int of_map_id(struct device_node *np, u32 id, 
	       const char *map_name, const char *map_mask_name,

	       struct device_node **target, u32 *id_out);



phys_addr_t of_dma_get_max_cpu_address(struct device_node *np);



#else /* CONFIG_OF */



static inline void of_core_init(void)
@@ -995,6 +997,11 @@ static inline int of_map_id(struct device_node *np, u32 id, 
	return -EINVAL;

}



static inline phys_addr_t of_dma_get_max_cpu_address(struct device_node *np)

{

	return PHYS_ADDR_MAX;

}



#define of_match_ptr(_ptr)	NULL

#define of_match_node(_matches, _node)	NULL

#endif /* CONFIG_OF */