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@xxxxxxxxxxx>
---
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);
--
git-series 0.9.1
--
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