x86/amd_node: Fix PCI device reference counting in amd_smn_init()grafted

The local "root" pointer is a temporary variable used during the device
search. Therefore, refcount related to the search iterators should be cleaned
up after the search is complete.

Use the __free() cleanup macro to ensure the refcount is decremented when the
temporary pointer goes out of scope.

Additionally, increment the refcount when caching a root pointer. This ensures
the in-use refcount is separate from the temporary search refcounting.

Finally, drop the redundant "root = NULL" before the second search loop. The
pci_get_class() iterator always decrements the refcount of its "from"
argument, so the first loop can only fall through with "root" already NULL.

Fixes: 0a4b61d9c2e4 ("x86/amd_node: Fix AMD root device caching")
Closes: https://sashiko.dev/#/patchset/20260806160159.230453-1-jason.andryuk%40amd.com
Reported-by: Sashiko <sashiko-bot@kernel.org>
Assisted-by: LLM
Signed-off-by: Yazen Ghannam <yazen.ghannam@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Mario Limonciello (AMD) <superm1@kernel.org>
Cc: <stable@kernel.org>
Link: https://patch.msgid.link/20260903154325.74343-1-yazen.ghannam@amd.com

1 files changed, 88 insertions, 0 deletions

diff --git a/Documentation/devicetree/bindings/fuse/nvidia,tegra20-fuse.yaml b/Documentation/devicetree/bindings/fuse/nvidia,tegra20-fuse.yaml
new file mode 100644
index 000000000..02f0b0462
--- /dev/null
+++ b/Documentation/devicetree/bindings/fuse/nvidia,tegra20-fuse.yaml
@@ -0,0 +1,88 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/fuse/nvidia,tegra20-fuse.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: NVIDIA Tegra FUSE block
+
+maintainers:
+  - Thierry Reding <thierry.reding@gmail.com>
+  - Jon Hunter <jonathanh@nvidia.com>
+
+properties:
+  compatible:
+    oneOf:
+      - enum:
+          - nvidia,tegra20-efuse
+          - nvidia,tegra30-efuse
+          - nvidia,tegra114-efuse
+          - nvidia,tegra124-efuse
+          - nvidia,tegra210-efuse
+          - nvidia,tegra186-efuse
+          - nvidia,tegra194-efuse
+          - nvidia,tegra234-efuse
+
+      - items:
+          - const: nvidia,tegra132-efuse
+          - const: nvidia,tegra124-efuse
+
+  reg:
+    maxItems: 1
+
+  clocks:
+    maxItems: 1
+
+  clock-names:
+    items:
+      - const: fuse
+
+  resets:
+    maxItems: 1
+
+  reset-names:
+    items:
+      - const: fuse
+
+  operating-points-v2: true
+
+  power-domains:
+    items:
+      - description: phandle to the core power domain
+
+additionalProperties: false
+
+required:
+  - compatible
+  - reg
+  - clocks
+  - clock-names
+
+if:
+  properties:
+    compatible:
+      contains:
+        enum:
+          - nvidia,tegra20-efuse
+          - nvidia,tegra30-efuse
+          - nvidia,tegra114-efuse
+          - nvidia,tegra124-efuse
+          - nvidia,tegra132-efuse
+          - nvidia,tegra210-efuse
+then:
+  required:
+    - resets
+    - reset-names
+
+examples:
+  - |
+    #include <dt-bindings/clock/tegra20-car.h>
+
+    fuse@7000f800 {
+        compatible = "nvidia,tegra20-efuse";
+        reg = <0x7000f800 0x400>;
+        clocks = <&tegra_car TEGRA20_CLK_FUSE>;
+        clock-names = "fuse";
+        resets = <&tegra_car 39>;
+        reset-names = "fuse";
+    };