Hi Lorenzo,
On 2020/6/19 16:20, Lorenzo Pieralisi wrote:
When the iort_match_node_callback is invoked for a named component
the match should be executed upon a device with an ACPI companion.
For devices with no ACPI companion set-up the ACPI device tree must be
walked in order to find the first parent node with a companion set and
check the parent node against the named component entry to check whether
there is a match and therefore an IORT node describing the in/out ID
translation for the device has been found.
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@xxxxxxx>
Cc: Will Deacon <will@xxxxxxxxxx>
Cc: Hanjun Guo <guohanjun@xxxxxxxxxx>
Cc: Sudeep Holla <sudeep.holla@xxxxxxx>
Cc: Catalin Marinas <catalin.marinas@xxxxxxx>
Cc: Robin Murphy <robin.murphy@xxxxxxx>
Cc: "Rafael J. Wysocki" <rjw@xxxxxxxxxxxxx>
---
drivers/acpi/arm64/iort.c | 20 ++++++++++++++++++--
1 file changed, 18 insertions(+), 2 deletions(-)
diff --git a/drivers/acpi/arm64/iort.c b/drivers/acpi/arm64/iort.c
index 28a6b387e80e..5eee81758184 100644
--- a/drivers/acpi/arm64/iort.c
+++ b/drivers/acpi/arm64/iort.c
@@ -264,15 +264,31 @@ static acpi_status iort_match_node_callback(struct acpi_iort_node *node,
if (node->type == ACPI_IORT_NODE_NAMED_COMPONENT) {
struct acpi_buffer buf = { ACPI_ALLOCATE_BUFFER, NULL };
- struct acpi_device *adev = to_acpi_device_node(dev->fwnode);
+ struct acpi_device *adev;
struct acpi_iort_named_component *ncomp;
+ struct device *nc_dev = dev;
+
+ /*
+ * Walk the device tree to find a device with an
+ * ACPI companion; there is no point in scanning
+ * IORT for a device matching a named component if
+ * the device does not have an ACPI companion to
+ * start with.
+ */
+ do {
+ adev = ACPI_COMPANION(nc_dev);
+ if (adev)
+ break;
+
+ nc_dev = nc_dev->parent;
+ } while (nc_dev);
I'm lost here, we need the ACPI_COMPANION (the same as
to_acpi_device_node()) of the device, but why do we need to go
up to find the parent node?
For a platform device, if I use its parent's full path name for
its named component entry, then it will match, but this will violate
the IORT spec.
Thanks
Hanjun
