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, 73 insertions, 0 deletions

diff --git a/include/clocksource/timer-xilinx.h b/include/clocksource/timer-xilinx.h
new file mode 100644
index 000000000..d116f18de
--- /dev/null
+++ b/include/clocksource/timer-xilinx.h
@@ -0,0 +1,73 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
+/*
+ * Copyright (C) 2021 Sean Anderson <sean.anderson@seco.com>
+ */
+
+#ifndef XILINX_TIMER_H
+#define XILINX_TIMER_H
+
+#include <linux/compiler.h>
+
+#define TCSR0	0x00
+#define TLR0	0x04
+#define TCR0	0x08
+#define TCSR1	0x10
+#define TLR1	0x14
+#define TCR1	0x18
+
+#define TCSR_MDT	BIT(0)
+#define TCSR_UDT	BIT(1)
+#define TCSR_GENT	BIT(2)
+#define TCSR_CAPT	BIT(3)
+#define TCSR_ARHT	BIT(4)
+#define TCSR_LOAD	BIT(5)
+#define TCSR_ENIT	BIT(6)
+#define TCSR_ENT	BIT(7)
+#define TCSR_TINT	BIT(8)
+#define TCSR_PWMA	BIT(9)
+#define TCSR_ENALL	BIT(10)
+#define TCSR_CASC	BIT(11)
+
+struct clk;
+struct device_node;
+struct regmap;
+
+/**
+ * struct xilinx_timer_priv - Private data for Xilinx AXI timer drivers
+ * @map: Regmap of the device, possibly with an offset
+ * @clk: Parent clock
+ * @max: Maximum value of the counters
+ */
+struct xilinx_timer_priv {
+	struct regmap *map;
+	struct clk *clk;
+	u64 max;
+};
+
+/**
+ * xilinx_timer_tlr_cycles() - Calculate the TLR for a period specified
+ *                             in clock cycles
+ * @priv: The timer's private data
+ * @tcsr: The value of the TCSR register for this counter
+ * @cycles: The number of cycles in this period
+ *
+ * Callers of this function MUST ensure that @cycles is representable as
+ * a TLR.
+ *
+ * Return: The calculated value for TLR
+ */
+u32 xilinx_timer_tlr_cycles(struct xilinx_timer_priv *priv, u32 tcsr,
+			    u64 cycles);
+
+/**
+ * xilinx_timer_get_period() - Get the current period of a counter
+ * @priv: The timer's private data
+ * @tlr: The value of TLR for this counter
+ * @tcsr: The value of TCSR for this counter
+ *
+ * Return: The period, in ns
+ */
+unsigned int xilinx_timer_get_period(struct xilinx_timer_priv *priv,
+				     u32 tlr, u32 tcsr);
+
+#endif /* XILINX_TIMER_H */