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From:   Armin Wolf <W_Armin@gmx.de>
To:     pali@kernel.org
Cc:     jdelvare@suse.com, linux@roeck-us.net, hdegoede@redhat.com,
        markgross@kernel.org, ilpo.jarvinen@linux.intel.com,
        platform-driver-x86@vger.kernel.org, linux-hwmon@vger.kernel.org,
        linux-kernel@vger.kernel.org
Subject: [PATCH v4 3/9] hwmon: (dell-smm) Move whitelist handling to module init
Date:   Thu, 23 Nov 2023 01:48:14 +0100
Message-Id: <20231123004820.50635-4-W_Armin@gmx.de>
In-Reply-To: <20231123004820.50635-1-W_Armin@gmx.de>
References: <20231123004820.50635-1-W_Armin@gmx.de>
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Precedence: bulk

Future SMM calling backends will not be able to probe during
module init, meaning the DMI tables used for whitelisting
features would have to drop their __initconst attribute.
Prevent this by moving the whitelist handling to module init.

Tested-by: <serverror@serverror.com>
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Armin Wolf <W_Armin@gmx.de>
=2D--
 drivers/hwmon/dell-smm-hwmon.c | 31 +++++++++++++++++--------------
 1 file changed, 17 insertions(+), 14 deletions(-)

diff --git a/drivers/hwmon/dell-smm-hwmon.c b/drivers/hwmon/dell-smm-hwmon=
.c
index 87d668799c9f..1cbdfd77773e 100644
=2D-- a/drivers/hwmon/dell-smm-hwmon.c
+++ b/drivers/hwmon/dell-smm-hwmon.c
@@ -90,8 +90,6 @@ struct dell_smm_data {
 	uint i8k_fan_mult;
 	uint i8k_pwm_mult;
 	uint i8k_fan_max;
-	unsigned int manual_fan;
-	unsigned int auto_fan;
 	int temp_type[DELL_SMM_NO_TEMP];
 	bool fan[DELL_SMM_NO_FANS];
 	int fan_type[DELL_SMM_NO_FANS];
@@ -138,6 +136,8 @@ MODULE_PARM_DESC(fan_max, "Maximum configurable fan sp=
eed (default: autodetect)"

 static bool disallow_fan_type_call, disallow_fan_support;

+static unsigned int manual_fan, auto_fan;
+
 static const char * const temp_labels[] =3D {
 	"CPU",
 	"GPU",
@@ -329,7 +329,7 @@ static int i8k_enable_fan_auto_mode(const struct dell_=
smm_data *data, bool enabl
 	if (disallow_fan_support)
 		return -EINVAL;

-	regs.eax =3D enable ? data->auto_fan : data->manual_fan;
+	regs.eax =3D enable ? auto_fan : manual_fan;
 	return dell_smm_call(data->ops, &regs);
 }

@@ -741,7 +741,7 @@ static umode_t dell_smm_is_visible(const void *drvdata=
, enum hwmon_sensor_types

 			break;
 		case hwmon_pwm_enable:
-			if (data->auto_fan)
+			if (auto_fan)
 				/*
 				 * There is no command for retrieve the current status
 				 * from BIOS, and userspace/firmware itself can change
@@ -1370,7 +1370,7 @@ static const struct dmi_system_id i8k_whitelist_fan_=
control[] __initconst =3D {
 static int __init dell_smm_probe(struct platform_device *pdev)
 {
 	struct dell_smm_data *data;
-	const struct dmi_system_id *id, *fan_control;
+	const struct dmi_system_id *id;
 	int ret;

 	data =3D devm_kzalloc(&pdev->dev, sizeof(struct dell_smm_data), GFP_KERN=
EL);
@@ -1406,15 +1406,6 @@ static int __init dell_smm_probe(struct platform_de=
vice *pdev)
 	data->i8k_fan_max =3D fan_max ? : I8K_FAN_HIGH;
 	data->i8k_pwm_mult =3D DIV_ROUND_UP(255, data->i8k_fan_max);

-	fan_control =3D dmi_first_match(i8k_whitelist_fan_control);
-	if (fan_control && fan_control->driver_data) {
-		const struct i8k_fan_control_data *control =3D fan_control->driver_data=
;
-
-		data->manual_fan =3D control->manual_fan;
-		data->auto_fan =3D control->auto_fan;
-		dev_info(&pdev->dev, "enabling support for setting automatic/manual fan=
 control\n");
-	}
-
 	ret =3D dell_smm_init_hwmon(&pdev->dev);
 	if (ret)
 		return ret;
@@ -1437,6 +1428,9 @@ static struct platform_device *dell_smm_device;
  */
 static void __init dell_smm_init_dmi(void)
 {
+	struct i8k_fan_control_data *control;
+	const struct dmi_system_id *id;
+
 	if (dmi_check_system(i8k_blacklist_fan_support_dmi_table)) {
 		if (!force) {
 			pr_notice("Disabling fan support due to BIOS bugs\n");
@@ -1454,6 +1448,15 @@ static void __init dell_smm_init_dmi(void)
 			pr_warn("Enabling fan type call despite BIOS bugs\n");
 		}
 	}
+
+	id =3D dmi_first_match(i8k_whitelist_fan_control);
+	if (id && id->driver_data) {
+		control =3D id->driver_data;
+		manual_fan =3D control->manual_fan;
+		auto_fan =3D control->auto_fan;
+
+		pr_info("Enabling support for setting automatic/manual fan control\n");
+	}
 }

 static int __init i8k_init(void)
=2D-
2.39.2