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, 51 insertions, 0 deletions

diff --git a/include/video/hecubafb.h b/include/video/hecubafb.h
new file mode 100644
index 000000000..7b9952339
--- /dev/null
+++ b/include/video/hecubafb.h
@@ -0,0 +1,51 @@
+/*
+ * hecubafb.h - definitions for the hecuba framebuffer driver
+ *
+ * Copyright (C) 2008 by Jaya Kumar
+ *
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License. See the file COPYING in the main directory of this archive for
+ * more details.
+ *
+ */
+
+#ifndef _LINUX_HECUBAFB_H_
+#define _LINUX_HECUBAFB_H_
+
+/* Apollo controller specific defines */
+#define APOLLO_START_NEW_IMG	0xA0
+#define APOLLO_STOP_IMG_DATA	0xA1
+#define APOLLO_DISPLAY_IMG	0xA2
+#define APOLLO_ERASE_DISPLAY	0xA3
+#define APOLLO_INIT_DISPLAY	0xA4
+
+/* Hecuba interface specific defines */
+#define HCB_WUP_BIT	0x01
+#define HCB_DS_BIT 	0x02
+#define HCB_RW_BIT 	0x04
+#define HCB_CD_BIT 	0x08
+#define HCB_ACK_BIT 	0x80
+
+/* struct used by hecuba. board specific stuff comes from *board */
+struct hecubafb_par {
+	struct fb_info *info;
+	struct hecuba_board *board;
+	void (*send_command)(struct hecubafb_par *, unsigned char);
+	void (*send_data)(struct hecubafb_par *, unsigned char);
+};
+
+/* board specific routines
+board drivers can implement wait_for_ack with interrupts if desired. if
+wait_for_ack is called with clear=0, then go to sleep and return when ack
+goes hi or if wait_for_ack with clear=1, then return when ack goes lo */
+struct hecuba_board {
+	struct module *owner;
+	void (*remove)(struct hecubafb_par *);
+	void (*set_ctl)(struct hecubafb_par *, unsigned char, unsigned char);
+	void (*set_data)(struct hecubafb_par *, unsigned char);
+	void (*wait_for_ack)(struct hecubafb_par *, int);
+	int (*init)(struct hecubafb_par *);
+};
+
+
+#endif