linux-kernel - [PATCH v3 1/5] platform/x86/intel/tpmi: Don't create devices for disabled features

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Date:   Mon,  4 Dec 2023 14:17:36 -0800
From:   Srinivas Pandruvada <srinivas.pandruvada@...ux.intel.com>
To:     hdegoede@...hat.com, markgross@...nel.org,
        ilpo.jarvinen@...ux.intel.com, andriy.shevchenko@...ux.intel.com
Cc:     platform-driver-x86@...r.kernel.org, linux-kernel@...r.kernel.org,
        Srinivas Pandruvada <srinivas.pandruvada@...ux.intel.com>
Subject: [PATCH v3 1/5] platform/x86/intel/tpmi: Don't create devices for disabled features

If some TPMI features are disabled, don't create auxiliary devices. In
this way feature drivers will not load.

While creating auxiliary devices, call tpmi_read_feature_status() to
check feature state and return if the feature is disabled without
creating a device.

Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@...ux.intel.com>
Reviewed-by: Hans de Goede <hdegoede@...hat.com>
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@...ux.intel.com>
---
v3
- Rebased on top of /pdx86/platform-drivers-x86 review-hans

v2
- Add comment for returning -EOPNOTSUPP

 drivers/platform/x86/intel/tpmi.c | 14 +++++++++++++-
 1 file changed, 13 insertions(+), 1 deletion(-)

diff --git a/drivers/platform/x86/intel/tpmi.c b/drivers/platform/x86/intel/tpmi.c
index 311abcac894a..09972e2b8a06 100644
--- a/drivers/platform/x86/intel/tpmi.c
+++ b/drivers/platform/x86/intel/tpmi.c
@@ -598,9 +598,21 @@ static int tpmi_create_device(struct intel_tpmi_info *tpmi_info,
 	struct intel_vsec_device *vsec_dev = tpmi_info->vsec_dev;
 	char feature_id_name[TPMI_FEATURE_NAME_LEN];
 	struct intel_vsec_device *feature_vsec_dev;
+	struct tpmi_feature_state feature_state;
 	struct resource *res, *tmp;
 	const char *name;
-	int i;
+	int i, ret;
+
+	ret = tpmi_read_feature_status(tpmi_info, pfs->pfs_header.tpmi_id, &feature_state);
+	if (ret)
+		return ret;
+
+	/*
+	 * If not enabled, continue to look at other features in the PFS, so return -EOPNOTSUPP.
+	 * This will not cause failure of loading of this driver.
+	 */
+	if (!feature_state.enabled)
+		return -EOPNOTSUPP;
 
 	name = intel_tpmi_name(pfs->pfs_header.tpmi_id);
 	if (!name)
-- 
2.40.1