[PATCH v5 1/2] media: ipu-bridge: don't reference the module image from software nodes

["D. Manresa" <dmanresa@gmail.com>]

The software nodes the bridge registers are deliberately never
unregistered, so that a later rebind can reuse them. Nothing reachable
from them may therefore point into the module image, but two properties
still do: the "link-frequencies" values point at cfg->link_freqs in
ipu_supported_sensors[], and the "lens-focus" property name is a string
literal.

Both dangle once the module is unloaded. Re-probing sensor drivers then
read poisoned link frequencies from the surviving nodes and fail:

  ov5693: supported link freq 419200000 not found

Copy both into struct ipu_sensor, where the other property names and
values already live.

Assisted-by: LLM
Fixes: 803abec64ef9 ("media: ipu3-cio2: Add cio2-bridge to ipu3-cio2 driver")
Fixes: 68b9bcc8a534 ("media: ipu3-cio2: Add support for instantiating i2c-clients for VCMs")
Tested-by: Fernando Rimoli <fernandorimoli11@gmail.com> # Surface Pro 9, IPU6 (8086:465d); boot and sensor rebind, not unload or rescan
Signed-off-by: D. Manresa <dmanresa@gmail.com>
---
 drivers/media/pci/intel/ipu-bridge.c | 12 +++++++++---
 include/media/ipu-bridge.h           |  6 ++++++
 2 files changed, 15 insertions(+), 3 deletions(-)

diff --git a/drivers/media/pci/intel/ipu-bridge.c b/drivers/media/pci/intel/ipu-bridge.c
index 3739c4a..aea4699 100644
--- a/drivers/media/pci/intel/ipu-bridge.c
+++ b/drivers/media/pci/intel/ipu-bridge.c
@@ -290,6 +290,7 @@ static const struct ipu_property_names prop_names = {
 	.remote_endpoint = "remote-endpoint",
 	.link_frequencies = "link-frequencies",
 	.clock_noncontinuous = "clock-noncontinuous",
+	.lens_focus = "lens-focus",
 };
 
 static const char * const ipu_vcm_types[] = {
@@ -623,7 +624,8 @@ static void ipu_bridge_create_fwnode_properties(
 		sensor->vcm_ref[0] =
 			SOFTWARE_NODE_REFERENCE(&sensor->swnodes[SWNODE_VCM]);
 		sensor->dev_properties[3] =
-			PROPERTY_ENTRY_REF_ARRAY("lens-focus", sensor->vcm_ref);
+			PROPERTY_ENTRY_REF_ARRAY(names->lens_focus,
+						 sensor->vcm_ref);
 	}
 
 	sensor->ep_properties[IPU_BRIDGE_NEXT_PROPERTY(i, EP_BUS_TYPE)] =
@@ -636,11 +638,15 @@ static void ipu_bridge_create_fwnode_properties(
 		PROPERTY_ENTRY_REF_ARRAY(names->remote_endpoint,
 					 sensor->local_ref);
 
-	if (cfg->nr_link_freqs > 0)
+	if (cfg->nr_link_freqs > 0) {
+		memcpy(sensor->link_freqs, cfg->link_freqs,
+		       cfg->nr_link_freqs * sizeof(*sensor->link_freqs));
+
 		sensor->ep_properties[IPU_BRIDGE_NEXT_PROPERTY(i, EP_LINK_FREQUENCIES)] =
 			PROPERTY_ENTRY_U64_ARRAY_LEN(names->link_frequencies,
-						     cfg->link_freqs,
+						     sensor->link_freqs,
 						     cfg->nr_link_freqs);
+	}
 
 	if (cfg->flags & IPU_BR_FL_CSI2_CLK_NONCONTINUOUS)
 		sensor->ep_properties[IPU_BRIDGE_NEXT_PROPERTY(i, EP_CLOCK_NONCONTINUOUS)] =
diff --git a/include/media/ipu-bridge.h b/include/media/ipu-bridge.h
index 3ef94c2..7c89fb6 100644
--- a/include/media/ipu-bridge.h
+++ b/include/media/ipu-bridge.h
@@ -136,6 +136,7 @@ struct ipu_property_names {
 	char remote_endpoint[16];
 	char link_frequencies[17];
 	char clock_noncontinuous[20];
+	char lens_focus[11];
 };
 
 struct ipu_node_names {
@@ -178,6 +179,11 @@ struct ipu_sensor {
 	const char *vcm_type;
 
 	struct ipu_property_names prop_names;
+	/*
+	 * The registered software nodes outlive the module, so the property
+	 * values they point at must not live in it.
+	 */
+	u64 link_freqs[MAX_NUM_LINK_FREQS];
 	struct property_entry ep_properties[IPU_BRIDGE_EP_NUM_ENTRIES];
 	struct property_entry dev_properties[5];
 	struct property_entry ipu_properties[3];
-- 
2.43.0