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| author | Nicolas Saenz Julienne <nsaenzjulienne@suse.de> | 2020-11-19 20:53:55 +0300 |
|---|---|---|
| committer | Catalin Marinas <catalin.marinas@arm.com> | 2020-11-20 12:34:13 +0300 |
| commit | 964db79d6c186cc2ecc6ae46f98eed7e0ea8cf71 (patch) | |
| tree | 0a23f95c22adfa863417019ce95f844a4e8d05fb /drivers/of | |
| parent | 9804f8c69b04a39d0ba41d19e6bdc6aa91c19725 (diff) | |
| download | linux-964db79d6c186cc2ecc6ae46f98eed7e0ea8cf71.tar.xz | |
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: 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>
Diffstat (limited to 'drivers/of')
| -rw-r--r-- | drivers/of/address.c | 42 |
1 files changed, 42 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 * |