[PATCH v4 2/5] of: Use memory-controllers property for DMA parent

Thierry Reding
2020-02-13T16:40:17Z

Prefer the memory-controllers property to determine the DMA parent of a
device over the interconnects property, which can be ambiguous since it
can be used to describe multiple paths to system memory.

Signed-off-by: Thierry Reding <treding@nvidia.com>
---
drivers/of/address.c | 25 ++++++++++++++++---------
1 file changed, 16 insertions(+), 9 deletions(-)

diff --git a/drivers/of/address.c b/drivers/of/address.c
index e8a39c3ec4d4..ae841bd36bb0 100644
--- a/drivers/of/address.c
+++ b/drivers/of/address.c
@@ -697,17 +697,24 @@ static struct device_node *__of_get_dma_parent(const struct device_node *np)
struct of_phandle_args args;
int ret, index;

- index = of_property_match_string(np, "interconnect-names", "dma-mem");
- if (index < 0)
- return of_get_parent(np);
+ ret = of_parse_phandle_with_args(np, "memory-controllers",
+ "#memory-controller-cells",
+ 0, &args);
+ if (!ret) {
+ return of_node_get(args.np);
+ }

- ret = of_parse_phandle_with_args(np, "interconnects",
- "#interconnect-cells",
- index, &args);
- if (ret < 0)
- return of_get_parent(np);
+ index = of_property_match_string(np, "interconnect-names", "dma-mem");
+ if (index >= 0) {
+ ret = of_parse_phandle_with_args(np, "interconnects",
+ "#interconnect-cells",
+ index, &args);
+ if (!ret) {
+ return of_node_get(args.np);
+ }
+ }

- return of_node_get(args.np);
+ return of_get_parent(np);
}

static struct device_node *of_get_next_dma_parent(struct device_node *np)