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, 100 insertions, 0 deletions

diff --git a/drivers/usb/chipidea/udc.h b/drivers/usb/chipidea/udc.h
new file mode 100644
index 000000000..c8a47389a
--- /dev/null
+++ b/drivers/usb/chipidea/udc.h
@@ -0,0 +1,100 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * udc.h - ChipIdea UDC structures
+ *
+ * Copyright (C) 2008 Chipidea - MIPS Technologies, Inc. All rights reserved.
+ *
+ * Author: David Lopo
+ */
+
+#ifndef __DRIVERS_USB_CHIPIDEA_UDC_H
+#define __DRIVERS_USB_CHIPIDEA_UDC_H
+
+#include <linux/list.h>
+
+#define CTRL_PAYLOAD_MAX   64
+#define RX        0  /* similar to USB_DIR_OUT but can be used as an index */
+#define TX        1  /* similar to USB_DIR_IN  but can be used as an index */
+
+/* DMA layout of transfer descriptors */
+struct ci_hw_td {
+	/* 0 */
+	__le32 next;
+#define TD_TERMINATE          BIT(0)
+#define TD_ADDR_MASK          (0xFFFFFFEUL << 5)
+	/* 1 */
+	__le32 token;
+#define TD_STATUS             (0x00FFUL <<  0)
+#define TD_STATUS_TR_ERR      BIT(3)
+#define TD_STATUS_DT_ERR      BIT(5)
+#define TD_STATUS_HALTED      BIT(6)
+#define TD_STATUS_ACTIVE      BIT(7)
+#define TD_MULTO              (0x0003UL << 10)
+#define TD_IOC                BIT(15)
+#define TD_TOTAL_BYTES        (0x7FFFUL << 16)
+	/* 2 */
+	__le32 page[5];
+#define TD_CURR_OFFSET        (0x0FFFUL <<  0)
+#define TD_FRAME_NUM          (0x07FFUL <<  0)
+#define TD_RESERVED_MASK      (0x0FFFUL <<  0)
+} __attribute__ ((packed, aligned(4)));
+
+/* DMA layout of queue heads */
+struct ci_hw_qh {
+	/* 0 */
+	__le32 cap;
+#define QH_IOS                BIT(15)
+#define QH_MAX_PKT            (0x07FFUL << 16)
+#define QH_ZLT                BIT(29)
+#define QH_MULT               (0x0003UL << 30)
+#define QH_ISO_MULT(x)		((x >> 11) & 0x03)
+	/* 1 */
+	__le32 curr;
+	/* 2 - 8 */
+	struct ci_hw_td		td;
+	/* 9 */
+	__le32 RESERVED;
+	struct usb_ctrlrequest   setup;
+} __attribute__ ((packed, aligned(4)));
+
+struct td_node {
+	struct list_head	td;
+	dma_addr_t		dma;
+	struct ci_hw_td		*ptr;
+	int			td_remaining_size;
+};
+
+/**
+ * struct ci_hw_req - usb request representation
+ * @req: request structure for gadget drivers
+ * @queue: link to QH list
+ * @tds: link to TD list
+ * @sgt: hold original sglist when bounce sglist
+ */
+struct ci_hw_req {
+	struct usb_request	req;
+	struct list_head	queue;
+	struct list_head	tds;
+	struct sg_table		sgt;
+};
+
+#ifdef CONFIG_USB_CHIPIDEA_UDC
+
+int ci_hdrc_gadget_init(struct ci_hdrc *ci);
+void ci_hdrc_gadget_destroy(struct ci_hdrc *ci);
+
+#else
+
+static inline int ci_hdrc_gadget_init(struct ci_hdrc *ci)
+{
+	return -ENXIO;
+}
+
+static inline void ci_hdrc_gadget_destroy(struct ci_hdrc *ci)
+{
+
+}
+
+#endif
+
+#endif /* __DRIVERS_USB_CHIPIDEA_UDC_H */