linux-kernel - [PATCH V2] firmware: arm_scmi: bus: bypass set fwnode for scmi cpufreq

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Message-Id: <20240729070325.2065286-1-peng.fan@oss.nxp.com>
Date: Mon, 29 Jul 2024 15:03:25 +0800
From: "Peng Fan (OSS)" <peng.fan@....nxp.com>
To: sudeep.holla@....com,
	cristian.marussi@....com,
	saravanak@...gle.com
Cc: linux-arm-kernel@...ts.infradead.org,
	linux-kernel@...r.kernel.org,
	arm-scmi@...r.kernel.org,
	Peng Fan <peng.fan@....com>
Subject: [PATCH V2] firmware: arm_scmi: bus: bypass set fwnode for scmi cpufreq

From: Peng Fan <peng.fan@....com>

Two drivers scmi_cpufreq.c and scmi_perf_domain.c both use
SCMI_PROTCOL_PERF protocol, but with different name, so two scmi devices
will be created. But the fwnode->dev could only point to one device.

If scmi cpufreq device created earlier, the fwnode->dev will point to
the scmi cpufreq device. Then the fw_devlink will link performance
domain user device(consumer) to the scmi cpufreq device(supplier).
But actually the performance domain user device, such as GPU, should use
the scmi perf device as supplier. Also if 'cpufreq.off=1' in bootargs,
the GPU driver will defer probe always, because of the scmi cpufreq
device not ready.

Because for cpufreq, no need use fw_devlink. So bypass setting fwnode
for scmi cpufreq device.

Fixes: 96da4a99ce50 ("firmware: arm_scmi: Set fwnode for the scmi_device")
Signed-off-by: Peng Fan <peng.fan@....com>
---

V2:
 Use A!=B to replace !(A == B)
 Add fixes tag
 This might be a workaround, but since this is a fix, it is simple for
 backporting.

V1:
 https://lore.kernel.org/all/20240717093515.327647-1-peng.fan@oss.nxp.com/

 drivers/firmware/arm_scmi/bus.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/firmware/arm_scmi/bus.c b/drivers/firmware/arm_scmi/bus.c
index 96b2e5f9a8ef..be91a82e0cda 100644
--- a/drivers/firmware/arm_scmi/bus.c
+++ b/drivers/firmware/arm_scmi/bus.c
@@ -395,7 +395,8 @@ __scmi_device_create(struct device_node *np, struct device *parent,
 	scmi_dev->id = id;
 	scmi_dev->protocol_id = protocol;
 	scmi_dev->dev.parent = parent;
-	device_set_node(&scmi_dev->dev, of_fwnode_handle(np));
+	if ((protocol != SCMI_PROTOCOL_PERF) || strcmp(name, "cpufreq"))
+		device_set_node(&scmi_dev->dev, of_fwnode_handle(np));
 	scmi_dev->dev.bus = &scmi_bus_type;
 	scmi_dev->dev.release = scmi_device_release;
 	dev_set_name(&scmi_dev->dev, "scmi_dev.%d", id);
-- 
2.37.1