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 | 26 ++++++++++++++++++++++---- 1 file changed, 22 insertions(+), 4 deletions(-)
diff --git a/drivers/of/address.c b/drivers/of/address.c index 9e637bf8102c..e4c8207871d1 100644 --- a/drivers/of/address.c +++ b/drivers/of/address.c @@ -680,10 +680,18 @@ EXPORT_SYMBOL(of_translate_address);
u64 of_translate_dma_address(struct device_node *dev, const __be32 *in_addr) { + struct of_phandle_args args; + struct device_node *parent = NULL; struct device_node *host; u64 ret;
- ret = __of_translate_address(dev, NULL, in_addr, "dma-ranges", &host); + ret = of_parse_phandle_with_args(dev, "dma-parent", + "#dma-parent-cells", + 0, &args); + if (!ret) + parent = args.np; + + ret = __of_translate_address(dev, parent, in_addr, "dma-ranges", &host);
if (host) { of_node_put(host); @@ -909,11 +917,21 @@ 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);