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of/address: Introduce of_dma_get_max_cpu_address()

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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: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
Reviewed-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20201119175400.9995-4-nsaenzjulienne@suse.de
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
This commit is contained in:
Nicolas Saenz Julienne
2020-11-19 18:53:55 +01:00
committed by Catalin Marinas
parent 9804f8c69b
commit 964db79d6c
2 changed files with 49 additions and 0 deletions
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42
drivers/of/address.c
View File

@@ -1024,6 +1024,48 @@ out:
} }
#endif /* CONFIG_HAS_DMA */ #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 * of_dma_is_coherent - Check if device is coherent
* @np: device node * @np: device node

7
include/linux/of.h
View File

@@ -558,6 +558,8 @@ int of_map_id(struct device_node *np, u32 id,
const char *map_name, const char *map_mask_name, const char *map_name, const char *map_mask_name,
struct device_node **target, u32 *id_out); struct device_node **target, u32 *id_out);
phys_addr_t of_dma_get_max_cpu_address(struct device_node *np);
#else /* CONFIG_OF */ #else /* CONFIG_OF */
static inline void of_core_init(void) 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; 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_ptr(_ptr) NULL
#define of_match_node(_matches, _node) NULL #define of_match_node(_matches, _node) NULL
#endif /* CONFIG_OF */ #endif /* CONFIG_OF */