Some SoCs have devices that are using a separate bus from the main bus to perform DMA.
These buses might have some restrictions and/or different mapping than from the CPU side, so we'd need to express those using the usual dma-ranges, but using a different DT node than the node's parent.
Add support for a dma-parent property that links to the DMA bus used by the device in such a case.
Signed-off-by: Maxime Ripard maxime.ripard@bootlin.com --- drivers/of/address.c | 28 ++++++++++++++++++++++++---- 1 file changed, 24 insertions(+), 4 deletions(-)
diff --git a/drivers/of/address.c b/drivers/of/address.c index e3267728a0cb..cc82f825ee03 100644 --- a/drivers/of/address.c +++ b/drivers/of/address.c @@ -647,7 +647,17 @@ EXPORT_SYMBOL(of_translate_address);
u64 of_translate_dma_address(struct device_node *dev, const __be32 *in_addr) { - return __of_translate_address(dev, NULL, in_addr, "dma-ranges"); + struct of_phandle_args args; + struct device_node *parent = NULL; + int ret; + + ret = of_parse_phandle_with_args(dev, "dma-parent", + "#dma-parent-cells", + 0, &args); + if (!ret) + parent = args.np; + + return __of_translate_address(dev, parent, in_addr, "dma-ranges"); } EXPORT_SYMBOL(of_translate_dma_address);
@@ -847,11 +857,21 @@ int of_dma_get_range(struct device_node *np, u64 *dma_addr, u64 *paddr, u64 *siz return -EINVAL;
while (1) { + struct of_phandle_args args; + naddr = of_n_addr_cells(node); nsize = of_n_size_cells(node); - node = of_get_next_parent(node); - if (!node) - break; + + ret = of_parse_phandle_with_args(node, "dma-parent", + "#dma-parent-cells", + 0, &args); + if (!ret) { + node = args.np; + } else { + node = of_get_next_parent(node); + if (!node) + break; + }
ranges = of_get_property(node, "dma-ranges", &len);