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, 43 insertions, 0 deletions

diff --git a/include/soc/canaan/k210-sysctl.h b/include/soc/canaan/k210-sysctl.h
new file mode 100644
index 000000000..0c2b2c2da
--- /dev/null
+++ b/include/soc/canaan/k210-sysctl.h
@@ -0,0 +1,43 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Copyright (C) 2019-20 Sean Anderson <seanga2@gmail.com>
+ * Copyright (c) 2020 Western Digital Corporation or its affiliates.
+ */
+#ifndef K210_SYSCTL_H
+#define K210_SYSCTL_H
+
+/*
+ * Kendryte K210 SoC system controller registers offsets.
+ * Taken from Kendryte SDK (kendryte-standalone-sdk).
+ */
+#define K210_SYSCTL_GIT_ID	0x00 /* Git short commit id */
+#define K210_SYSCTL_UART_BAUD	0x04 /* Default UARTHS baud rate */
+#define K210_SYSCTL_PLL0	0x08 /* PLL0 controller */
+#define K210_SYSCTL_PLL1	0x0C /* PLL1 controller */
+#define K210_SYSCTL_PLL2	0x10 /* PLL2 controller */
+#define K210_SYSCTL_PLL_LOCK	0x18 /* PLL lock tester */
+#define K210_SYSCTL_ROM_ERROR	0x1C /* AXI ROM detector */
+#define K210_SYSCTL_SEL0	0x20 /* Clock select controller 0 */
+#define K210_SYSCTL_SEL1	0x24 /* Clock select controller 1 */
+#define K210_SYSCTL_EN_CENT	0x28 /* Central clock enable */
+#define K210_SYSCTL_EN_PERI	0x2C /* Peripheral clock enable */
+#define K210_SYSCTL_SOFT_RESET	0x30 /* Soft reset ctrl */
+#define K210_SYSCTL_PERI_RESET	0x34 /* Peripheral reset controller */
+#define K210_SYSCTL_THR0	0x38 /* Clock threshold controller 0 */
+#define K210_SYSCTL_THR1	0x3C /* Clock threshold controller 1 */
+#define K210_SYSCTL_THR2	0x40 /* Clock threshold controller 2 */
+#define K210_SYSCTL_THR3	0x44 /* Clock threshold controller 3 */
+#define K210_SYSCTL_THR4	0x48 /* Clock threshold controller 4 */
+#define K210_SYSCTL_THR5	0x4C /* Clock threshold controller 5 */
+#define K210_SYSCTL_THR6	0x50 /* Clock threshold controller 6 */
+#define K210_SYSCTL_MISC	0x54 /* Miscellaneous controller */
+#define K210_SYSCTL_PERI	0x58 /* Peripheral controller */
+#define K210_SYSCTL_SPI_SLEEP	0x5C /* SPI sleep controller */
+#define K210_SYSCTL_RESET_STAT	0x60 /* Reset source status */
+#define K210_SYSCTL_DMA_SEL0	0x64 /* DMA handshake selector 0 */
+#define K210_SYSCTL_DMA_SEL1	0x68 /* DMA handshake selector 1 */
+#define K210_SYSCTL_POWER_SEL	0x6C /* IO Power Mode Select controller */
+
+void k210_clk_early_init(void __iomem *regs);
+
+#endif