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

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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: Rob Herring <robh@kernel.org>
This commit is contained in:
Rob Herring 2020-02-06 14:26:40 +00:00
parent 7a8b64d17e
commit 9d55bebd98
1 changed files with 24 additions and 4 deletions
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28
drivers/of/address.c
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@ -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);