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, 57 insertions, 0 deletions

diff --git a/drivers/bcma/scan.h b/drivers/bcma/scan.h
new file mode 100644
index 000000000..e53079a3d
--- /dev/null
+++ b/drivers/bcma/scan.h
@@ -0,0 +1,57 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef BCMA_SCAN_H_
+#define BCMA_SCAN_H_
+
+#define BCMA_ADDR_BASE		0x18000000
+#define BCMA_WRAP_BASE		0x18100000
+
+#define SCAN_ER_VALID		0x00000001
+#define SCAN_ER_TAGX		0x00000006 /* we have to ignore 0x8 bit when checking tag for SCAN_ER_TAG_ADDR */
+#define SCAN_ER_TAG		0x0000000E
+#define  SCAN_ER_TAG_CI		0x00000000
+#define  SCAN_ER_TAG_MP		0x00000002
+#define  SCAN_ER_TAG_ADDR	0x00000004
+#define  SCAN_ER_TAG_END	0x0000000E
+#define SCAN_ER_BAD		0xFFFFFFFF
+
+#define SCAN_CIA_CLASS		0x000000F0
+#define SCAN_CIA_CLASS_SHIFT	4
+#define SCAN_CIA_ID		0x000FFF00
+#define SCAN_CIA_ID_SHIFT	8
+#define SCAN_CIA_MANUF		0xFFF00000
+#define SCAN_CIA_MANUF_SHIFT	20
+
+#define SCAN_CIB_NMP		0x000001F0
+#define SCAN_CIB_NMP_SHIFT	4
+#define SCAN_CIB_NSP		0x00003E00
+#define SCAN_CIB_NSP_SHIFT	9
+#define SCAN_CIB_NMW		0x0007C000
+#define SCAN_CIB_NMW_SHIFT	14
+#define SCAN_CIB_NSW		0x00F80000
+#define SCAN_CIB_NSW_SHIFT	19
+#define SCAN_CIB_REV		0xFF000000
+#define SCAN_CIB_REV_SHIFT	24
+
+#define SCAN_ADDR_AG32		0x00000008
+#define SCAN_ADDR_SZ		0x00000030
+#define SCAN_ADDR_SZ_SHIFT	4
+#define  SCAN_ADDR_SZ_4K	0x00000000
+#define  SCAN_ADDR_SZ_8K	0x00000010
+#define  SCAN_ADDR_SZ_16K	0x00000020
+#define  SCAN_ADDR_SZ_SZD	0x00000030
+#define SCAN_ADDR_TYPE		0x000000C0
+#define  SCAN_ADDR_TYPE_SLAVE	0x00000000
+#define  SCAN_ADDR_TYPE_BRIDGE	0x00000040
+#define  SCAN_ADDR_TYPE_SWRAP	0x00000080
+#define  SCAN_ADDR_TYPE_MWRAP	0x000000C0
+#define SCAN_ADDR_PORT		0x00000F00
+#define SCAN_ADDR_PORT_SHIFT	8
+#define SCAN_ADDR_ADDR		0xFFFFF000
+
+#define SCAN_ADDR_SZ_BASE	0x00001000	/* 4KB */
+
+#define SCAN_SIZE_SZ_ALIGN	0x00000FFF
+#define SCAN_SIZE_SZ		0xFFFFF000
+#define SCAN_SIZE_SG32		0x00000008
+
+#endif /* BCMA_SCAN_H_ */