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, 74 insertions, 0 deletions

diff --git a/include/video/broadsheetfb.h b/include/video/broadsheetfb.h
new file mode 100644
index 000000000..548d28f4e
--- /dev/null
+++ b/include/video/broadsheetfb.h
@@ -0,0 +1,74 @@
+/*
+ * broadsheetfb.h - definitions for the broadsheet 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_BROADSHEETFB_H_
+#define _LINUX_BROADSHEETFB_H_
+
+/* Broadsheet command defines */
+#define BS_CMD_INIT_SYS_RUN	0x06
+#define BS_CMD_INIT_DSPE_CFG	0x09
+#define BS_CMD_INIT_DSPE_TMG	0x0A
+#define BS_CMD_INIT_ROTMODE	0x0B
+#define BS_CMD_RD_REG		0x10
+#define BS_CMD_WR_REG		0x11
+#define BS_CMD_LD_IMG		0x20
+#define BS_CMD_LD_IMG_AREA	0x22
+#define BS_CMD_LD_IMG_END	0x23
+#define BS_CMD_WAIT_DSPE_TRG	0x28
+#define BS_CMD_WAIT_DSPE_FREND	0x29
+#define BS_CMD_RD_WFM_INFO	0x30
+#define BS_CMD_UPD_INIT		0x32
+#define BS_CMD_UPD_FULL		0x33
+#define BS_CMD_UPD_GDRV_CLR	0x37
+
+/* Broadsheet register interface defines */
+#define BS_REG_REV		0x00
+#define BS_REG_PRC		0x02
+
+/* Broadsheet pin interface specific defines */
+#define BS_CS	0x01
+#define BS_DC 	0x02
+#define BS_WR 	0x03
+
+/* Broadsheet IO interface specific defines */
+#define BS_MMIO_CMD	0x01
+#define BS_MMIO_DATA	0x02
+
+/* struct used by broadsheet. board specific stuff comes from *board */
+struct broadsheetfb_par {
+	struct fb_info *info;
+	struct broadsheet_board *board;
+	void (*write_reg)(struct broadsheetfb_par *, u16 reg, u16 val);
+	u16 (*read_reg)(struct broadsheetfb_par *, u16 reg);
+	wait_queue_head_t waitq;
+	int panel_index;
+	struct mutex io_lock;
+};
+
+/* board specific routines */
+struct broadsheet_board {
+	struct module *owner;
+	int (*init)(struct broadsheetfb_par *);
+	int (*wait_for_rdy)(struct broadsheetfb_par *);
+	void (*cleanup)(struct broadsheetfb_par *);
+	int (*get_panel_type)(void);
+	int (*setup_irq)(struct fb_info *);
+
+	/* Functions for boards that use GPIO */
+	void (*set_ctl)(struct broadsheetfb_par *, unsigned char, u8);
+	void (*set_hdb)(struct broadsheetfb_par *, u16);
+	u16 (*get_hdb)(struct broadsheetfb_par *);
+
+	/* Functions for boards that have specialized MMIO */
+	void (*mmio_write)(struct broadsheetfb_par *, int type, u16);
+	u16 (*mmio_read)(struct broadsheetfb_par *);
+};
+#endif