Thread (33 messages) 33 messages, 3 authors, 26d ago

Re: [PATCH v3 6/9] firmware: arm_scmi: Refactor protocol device creation logic

From: Jonathan Cameron <hidden>
Date: 2026-08-24 17:49:55
Also in: arm-scmi

On Thu, 13 Aug 2026 12:33:01 +0100
Sudeep Holla [off-list ref] wrote:
Move the protocol validation and device creation logic in scmi_probe()
into a reusable scmi_device_check_create() helper.

The helper centralizes checks for the protocol ID range, implementation
availability and duplicate activation before invoking
scmi_create_protocol_devices(). This preserves the existing behavior
while allowing the logic to be reused by the ACPI path, where protocol
child fwnodes are absent.

No functional change intended.

Signed-off-by: Sudeep Holla <sudeep.holla@kernel.org>
A trivial thing and one follow on from earlier.  For that just be consistent
with what you choose to do for the earlier comment.

Reviewed-by: Jonathan Cameron <redacted>
quoted hunk ↗ jump to hunk
---
 drivers/firmware/arm_scmi/driver.c | 60 ++++++++++++++++++++++----------------
 1 file changed, 35 insertions(+), 25 deletions(-)
diff --git a/drivers/firmware/arm_scmi/driver.c b/drivers/firmware/arm_scmi/driver.c
index aad678db0f6e..951ba3df6ba6 100644
--- a/drivers/firmware/arm_scmi/driver.c
+++ b/drivers/firmware/arm_scmi/driver.c
@@ -3244,6 +3244,40 @@ static void scmi_enable_matching_quirks(struct scmi_info *info)
 			   rev->sub_vendor_id, rev->impl_ver);
 }
 
+static void scmi_device_check_create(struct fwnode_handle *fwnode, int prot_id,
+				     struct scmi_info *info)
+{
+	int ret;
+	struct device *dev = info->dev;
+	struct scmi_handle *handle = &info->handle;
+
+	if (!FIELD_FIT(MSG_PROTOCOL_ID_MASK, prot_id)) {
+		dev_err(dev, "Out of range protocol %d\n", prot_id);
+		return;
+	}
+
+	if (!scmi_is_protocol_implemented(handle, prot_id)) {
+		dev_err(dev, "SCMI protocol %d not implemented\n",
+			prot_id);
Fits on one line. I didn't check if you modify this later in the series
though so if this is churn reduction, fine to leave it as it stands.
+		return;
+	}
+
+	/*
+	 * Save this valid fwnode protocol descriptor amongst
+	 * @active_protocols for this SCMI instance.
+	 */
+	ret = idr_alloc(&info->active_protocols, fwnode,
+			prot_id, prot_id + 1, GFP_KERNEL);
+	if (ret != prot_id) {
+		dev_err(dev, "SCMI protocol %d already activated. Skip\n",
+			prot_id);
+		return;
+	}
+
+	fwnode_handle_get(fwnode);
+	scmi_create_protocol_devices(fwnode, info, prot_id, NULL);
If you take the suggest I made earlier to make the hand over of ownership
slightly more obvious by using the return value of fwmonde_handle_get()
then applies here too.
+}
  
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