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, 33 insertions, 0 deletions

diff --git a/include/sound/sdca_regmap.h b/include/sound/sdca_regmap.h
new file mode 100644
index 000000000..792540a53
--- /dev/null
+++ b/include/sound/sdca_regmap.h
@@ -0,0 +1,33 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * The MIPI SDCA specification is available for public downloads at
+ * https://www.mipi.org/mipi-sdca-v1-0-download
+ *
+ * Copyright (C) 2025 Cirrus Logic, Inc. and
+ *                    Cirrus Logic International Semiconductor Ltd.
+ */
+
+#ifndef __SDCA_REGMAP_H__
+#define __SDCA_REGMAP_H__
+
+struct device;
+struct sdca_function_data;
+struct regmap;
+struct reg_default;
+
+bool sdca_regmap_readable(struct sdca_function_data *function, unsigned int reg);
+bool sdca_regmap_writeable(struct sdca_function_data *function, unsigned int reg);
+bool sdca_regmap_volatile(struct sdca_function_data *function, unsigned int reg);
+bool sdca_regmap_deferrable(struct sdca_function_data *function, unsigned int reg);
+int sdca_regmap_mbq_size(struct sdca_function_data *function, unsigned int reg);
+
+int sdca_regmap_count_constants(struct device *dev, struct sdca_function_data *function);
+int sdca_regmap_populate_constants(struct device *dev, struct sdca_function_data *function,
+				   struct reg_default *consts);
+
+int sdca_regmap_write_defaults(struct device *dev, struct regmap *regmap,
+			       struct sdca_function_data *function);
+int sdca_regmap_write_init(struct device *dev, struct regmap *regmap,
+			   struct sdca_function_data *function);
+
+#endif // __SDCA_REGMAP_H__