linux-kernel - [PATCH v2 1/4] firmware: arm_scmi: Bypass setting fwnode for scmi cpufreq

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Message-Id: <20250120-scmi-fwdevlink-v2-1-3af2fa37dbac@nxp.com>
Date: Mon, 20 Jan 2025 15:13:29 +0800
From: "Peng Fan (OSS)" <peng.fan@....nxp.com>
To: Sudeep Holla <sudeep.holla@....com>, 
 Cristian Marussi <cristian.marussi@....com>, 
 Saravana Kannan <saravanak@...gle.com>, 
 Linus Walleij <linus.walleij@...aro.org>, 
 Dong Aisheng <aisheng.dong@....com>, Fabio Estevam <festevam@...il.com>, 
 Shawn Guo <shawnguo@...nel.org>, Jacky Bai <ping.bai@....com>, 
 Pengutronix Kernel Team <kernel@...gutronix.de>, 
 Sascha Hauer <s.hauer@...gutronix.de>
Cc: arm-scmi@...r.kernel.org, linux-arm-kernel@...ts.infradead.org, 
 linux-kernel@...r.kernel.org, linux-gpio@...r.kernel.org, 
 imx@...ts.linux.dev, Peng Fan <peng.fan@....com>
Subject: [PATCH v2 1/4] firmware: arm_scmi: Bypass setting 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>
---
 drivers/firmware/arm_scmi/bus.c | 17 ++++++++++++++++-
 1 file changed, 16 insertions(+), 1 deletion(-)

diff --git a/drivers/firmware/arm_scmi/bus.c b/drivers/firmware/arm_scmi/bus.c
index 2c853c84b58f530898057e4ab274ba76070de05e..7850eb7710f499888d32aebf5d99df63db8bfa26 100644
--- a/drivers/firmware/arm_scmi/bus.c
+++ b/drivers/firmware/arm_scmi/bus.c
@@ -344,6 +344,21 @@ static void __scmi_device_destroy(struct scmi_device *scmi_dev)
 	device_unregister(&scmi_dev->dev);
 }
 
+static int
+__scmi_device_set_node(struct scmi_device *scmi_dev, struct device_node *np,
+		       int protocol, const char *name)
+{
+	/* cpufreq device does not need to be supplier from devlink perspective */
+	if ((protocol == SCMI_PROTOCOL_PERF) && !strcmp(name, "cpufreq")) {
+		scmi_dev->dev.of_node = np;
+		return 0;
+	}
+
+	device_set_node(&scmi_dev->dev, of_fwnode_handle(np));
+
+	return 0;
+}
+
 static struct scmi_device *
 __scmi_device_create(struct device_node *np, struct device *parent,
 		     int protocol, const char *name)
@@ -396,7 +411,7 @@ __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));
+	__scmi_device_set_node(scmi_dev, np, protocol, name);
 	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