diff options
| -rw-r--r-- | drivers/of/address.c | 42 | ||||
| -rw-r--r-- | include/linux/of.h | 7 |
2 files changed, 49 insertions, 0 deletions
diff --git a/drivers/of/address.c b/drivers/of/address.c index eb9ab4f1e80b..09c0af7fd1c4 100644 --- a/drivers/of/address.c +++ b/drivers/of/address.c @@ -1025,6 +1025,48 @@ out: #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 * diff --git a/include/linux/of.h b/include/linux/of.h index 5d51891cbf1a..9ed5b8532c30 100644 --- a/include/linux/of.h +++ b/include/linux/of.h @@ -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 */ |