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, 49 insertions, 0 deletions

diff --git a/drivers/power/sequencing/Kconfig b/drivers/power/sequencing/Kconfig
new file mode 100644
index 000000000..1c5f5820f
--- /dev/null
+++ b/drivers/power/sequencing/Kconfig
@@ -0,0 +1,49 @@
+# SPDX-License-Identifier: GPL-2.0-only
+
+menuconfig POWER_SEQUENCING
+	tristate "Power Sequencing support"
+	help
+	  Say Y here to enable the Power Sequencing subsystem.
+
+	  This subsystem is designed to control power to devices that share
+	  complex resources and/or require specific power sequences to be run
+	  during power-up.
+
+	  If unsure, say no.
+
+if POWER_SEQUENCING
+
+config POWER_SEQUENCING_QCOM_WCN
+	tristate "Qualcomm WCN family PMU driver"
+	default m if ARCH_QCOM
+	depends on OF || COMPILE_TEST
+	help
+	  Say Y here to enable the power sequencing driver for Qualcomm
+	  WCN Bluetooth/WLAN chipsets.
+
+	  Typically, a package from the Qualcomm WCN family contains the BT
+	  and WLAN modules whose power is controlled by the PMU module. As the
+	  former two share the power-up sequence which is executed by the PMU,
+	  this driver is needed for correct power control or else we'd risk not
+	  respecting the required delays between enabling Bluetooth and WLAN.
+
+config POWER_SEQUENCING_TH1520_GPU
+	tristate "T-HEAD TH1520 GPU power sequencing driver"
+	depends on (ARCH_THEAD && AUXILIARY_BUS) || COMPILE_TEST
+	help
+	  Say Y here to enable the power sequencing driver for the TH1520 SoC
+	  GPU. This driver handles the complex clock and reset sequence
+	  required to power on the Imagination BXM GPU on this platform.
+
+config POWER_SEQUENCING_PCIE_M2
+	tristate "PCIe M.2 connector power sequencing driver"
+	depends on OF
+	depends on PCI
+	depends on SERIAL_DEV_BUS
+	select OF_DYNAMIC
+	help
+	  Say Y here to enable the power sequencing driver for PCIe M.2
+	  connectors. This driver handles the power sequencing for the M.2
+	  connectors exposing multiple interfaces like PCIe, SATA, UART, etc...
+
+endif