Commit 9d55bebd authored by Rob Herring's avatar Rob Herring
Browse files

of/address: Support multiple 'dma-ranges' entries 



Currently, the DMA offset and mask for a device are set based only on the
first 'dma-ranges' entry. We should really be using all the entries. The
kernel doesn't yet support multiple offsets and sizes, so the best we can
do is to find the biggest size for a single offset. The algorithm is
copied from acpi_dma_get_range().

If there's different offsets from the first entry, then we warn and
continue. It really should be an error, but this will likely break
existing DTs.

Signed-off-by: default avatarRob Herring <robh@kernel.org>
parent 7a8b64d1

drivers/of/address.c

+24 −4
Original line number Diff line number Diff line
@@ -944,6 +944,7 @@ int of_dma_get_range(struct device_node *np, u64 *dma_addr, u64 *paddr, u64 *siz 
	bool found_dma_ranges = false;

	struct of_range_parser parser;

	struct of_range range;

	u64 dma_start = U64_MAX, dma_end = 0, dma_offset = 0;



	while (node) {

		ranges = of_get_property(node, "dma-ranges", &len);
@@ -974,14 +975,33 @@ int of_dma_get_range(struct device_node *np, u64 *dma_addr, u64 *paddr, u64 *siz 
		pr_debug("dma_addr(%llx) cpu_addr(%llx) size(%llx)\n",

			 range.bus_addr, range.cpu_addr, range.size);



		*dma_addr = range.bus_addr;

		*paddr = range.cpu_addr;

		*size = range.size;

		if (dma_offset && range.cpu_addr - range.bus_addr != dma_offset) {

			pr_warn("Can't handle multiple dma-ranges with different offsets on node(%pOF)\n", node);

			/* Don't error out as we'd break some existing DTs */

			continue;

		}

		dma_offset = range.cpu_addr - range.bus_addr;



		/* Take lower and upper limits */

		if (range.bus_addr < dma_start)

			dma_start = range.bus_addr;

		if (range.bus_addr + range.size > dma_end)

			dma_end = range.bus_addr + range.size;

	}



	if (dma_start >= dma_end) {

		ret = -EINVAL;

		pr_debug("Invalid DMA ranges configuration on node(%pOF)\n",

			 node);

		goto out;

	}



	pr_err("translation of DMA ranges failed on node(%pOF)\n", np);

	*dma_addr = dma_start;

	*size = dma_end - dma_start;

	*paddr = dma_start + dma_offset;



	pr_debug("final: dma_addr(%llx) cpu_addr(%llx) size(%llx)\n",

		 *dma_addr, *paddr, *size);



out:

	of_node_put(node);

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