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, 117 insertions, 0 deletions

diff --git a/include/pcmcia/cisreg.h b/include/pcmcia/cisreg.h
new file mode 100644
index 000000000..6c4829afa
--- /dev/null
+++ b/include/pcmcia/cisreg.h
@@ -0,0 +1,117 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * cisreg.h
+ *
+ * The initial developer of the original code is David A. Hinds
+ * <dahinds@users.sourceforge.net>.  Portions created by David A. Hinds
+ * are Copyright (C) 1999 David A. Hinds.  All Rights Reserved.
+ *
+ * (C) 1999             David A. Hinds
+ */
+
+#ifndef _LINUX_CISREG_H
+#define _LINUX_CISREG_H
+
+/*
+ * Offsets from ConfigBase for CIS registers
+ */
+#define CISREG_COR		0x00
+#define CISREG_CCSR		0x02
+#define CISREG_PRR		0x04
+#define CISREG_SCR		0x06
+#define CISREG_ESR		0x08
+#define CISREG_IOBASE_0		0x0a
+#define CISREG_IOBASE_1		0x0c
+#define CISREG_IOBASE_2		0x0e
+#define CISREG_IOBASE_3		0x10
+#define CISREG_IOSIZE		0x12
+
+/*
+ * Configuration Option Register
+ */
+#define COR_CONFIG_MASK		0x3f
+#define COR_MFC_CONFIG_MASK	0x38
+#define COR_FUNC_ENA		0x01
+#define COR_ADDR_DECODE		0x02
+#define COR_IREQ_ENA		0x04
+#define COR_LEVEL_REQ		0x40
+#define COR_SOFT_RESET		0x80
+
+/*
+ * Card Configuration and Status Register
+ */
+#define CCSR_INTR_ACK		0x01
+#define CCSR_INTR_PENDING	0x02
+#define CCSR_POWER_DOWN		0x04
+#define CCSR_AUDIO_ENA		0x08
+#define CCSR_IOIS8		0x20
+#define CCSR_SIGCHG_ENA		0x40
+#define CCSR_CHANGED		0x80
+
+/*
+ * Pin Replacement Register
+ */
+#define PRR_WP_STATUS		0x01
+#define PRR_READY_STATUS	0x02
+#define PRR_BVD2_STATUS		0x04
+#define PRR_BVD1_STATUS		0x08
+#define PRR_WP_EVENT		0x10
+#define PRR_READY_EVENT		0x20
+#define PRR_BVD2_EVENT		0x40
+#define PRR_BVD1_EVENT		0x80
+
+/*
+ * Socket and Copy Register
+ */
+#define SCR_SOCKET_NUM		0x0f
+#define SCR_COPY_NUM		0x70
+
+/*
+ * Extended Status Register
+ */
+#define ESR_REQ_ATTN_ENA	0x01
+#define ESR_REQ_ATTN		0x10
+
+/*
+ * CardBus Function Status Registers
+ */
+#define CBFN_EVENT		0x00
+#define CBFN_MASK		0x04
+#define CBFN_STATE		0x08
+#define CBFN_FORCE		0x0c
+
+/*
+ * These apply to all the CardBus function registers
+ */
+#define CBFN_WP			0x0001
+#define CBFN_READY		0x0002
+#define CBFN_BVD2		0x0004
+#define CBFN_BVD1		0x0008
+#define CBFN_GWAKE		0x0010
+#define CBFN_INTR		0x8000
+
+/*
+ * Extra bits in the Function Event Mask Register
+ */
+#define FEMR_BAM_ENA		0x0020
+#define FEMR_PWM_ENA		0x0040
+#define FEMR_WKUP_MASK		0x4000
+
+/*
+ * Indirect Addressing Registers for Zoomed Video: these are addresses
+ * in common memory space
+ */
+#define CISREG_ICTRL0		0x02	/* control registers */
+#define CISREG_ICTRL1		0x03
+#define CISREG_IADDR0		0x04	/* address registers */
+#define CISREG_IADDR1		0x05
+#define CISREG_IADDR2		0x06
+#define CISREG_IADDR3		0x07
+#define CISREG_IDATA0		0x08	/* data registers */
+#define CISREG_IDATA1		0x09
+
+#define ICTRL0_COMMON		0x01
+#define ICTRL0_AUTOINC		0x02
+#define ICTRL0_BYTEGRAN		0x04
+
+#endif /* _LINUX_CISREG_H */