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, 135 insertions, 0 deletions

diff --git a/drivers/clk/sprd/gate.c b/drivers/clk/sprd/gate.c
new file mode 100644
index 000000000..56e1714b5
--- /dev/null
+++ b/drivers/clk/sprd/gate.c
@@ -0,0 +1,135 @@
+// SPDX-License-Identifier: GPL-2.0
+//
+// Spreadtrum gate clock driver
+//
+// Copyright (C) 2017 Spreadtrum, Inc.
+// Author: Chunyan Zhang <chunyan.zhang@spreadtrum.com>
+
+#include <linux/clk-provider.h>
+#include <linux/regmap.h>
+
+#include "gate.h"
+
+static void clk_gate_toggle(const struct sprd_gate *sg, bool en)
+{
+	const struct sprd_clk_common *common = &sg->common;
+	unsigned int reg;
+	bool set = sg->flags & CLK_GATE_SET_TO_DISABLE ? true : false;
+
+	set ^= en;
+
+	regmap_read(common->regmap, common->reg, &reg);
+
+	if (set)
+		reg |= sg->enable_mask;
+	else
+		reg &= ~sg->enable_mask;
+
+	regmap_write(common->regmap, common->reg, reg);
+}
+
+static void clk_sc_gate_toggle(const struct sprd_gate *sg, bool en)
+{
+	const struct sprd_clk_common *common = &sg->common;
+	bool set = sg->flags & CLK_GATE_SET_TO_DISABLE ? 1 : 0;
+	unsigned int offset;
+
+	set ^= en;
+
+	/*
+	 * Each set/clear gate clock has three registers:
+	 * common->reg			- base register
+	 * common->reg + offset		- set register
+	 * common->reg + 2 * offset	- clear register
+	 */
+	offset = set ? sg->sc_offset : sg->sc_offset * 2;
+
+	regmap_write(common->regmap, common->reg + offset,
+			  sg->enable_mask);
+}
+
+static void sprd_gate_disable(struct clk_hw *hw)
+{
+	struct sprd_gate *sg = hw_to_sprd_gate(hw);
+
+	clk_gate_toggle(sg, false);
+}
+
+static int sprd_gate_enable(struct clk_hw *hw)
+{
+	struct sprd_gate *sg = hw_to_sprd_gate(hw);
+
+	clk_gate_toggle(sg, true);
+
+	return 0;
+}
+
+static void sprd_sc_gate_disable(struct clk_hw *hw)
+{
+	struct sprd_gate *sg = hw_to_sprd_gate(hw);
+
+	clk_sc_gate_toggle(sg, false);
+}
+
+static int sprd_sc_gate_enable(struct clk_hw *hw)
+{
+	struct sprd_gate *sg = hw_to_sprd_gate(hw);
+
+	clk_sc_gate_toggle(sg, true);
+
+	return 0;
+}
+
+static int sprd_pll_sc_gate_prepare(struct clk_hw *hw)
+{
+	struct sprd_gate *sg = hw_to_sprd_gate(hw);
+
+	clk_sc_gate_toggle(sg, true);
+	udelay(sg->udelay);
+
+	return 0;
+}
+
+static int sprd_gate_is_enabled(struct clk_hw *hw)
+{
+	struct sprd_gate *sg = hw_to_sprd_gate(hw);
+	struct sprd_clk_common *common = &sg->common;
+	struct clk_hw *parent;
+	unsigned int reg;
+
+	if (sg->flags & SPRD_GATE_NON_AON) {
+		parent = clk_hw_get_parent(hw);
+		if (!parent || !clk_hw_is_enabled(parent))
+			return 0;
+	}
+
+	regmap_read(common->regmap, common->reg, &reg);
+
+	if (sg->flags & CLK_GATE_SET_TO_DISABLE)
+		reg ^= sg->enable_mask;
+
+	reg &= sg->enable_mask;
+
+	return reg ? 1 : 0;
+}
+
+const struct clk_ops sprd_gate_ops = {
+	.disable	= sprd_gate_disable,
+	.enable		= sprd_gate_enable,
+	.is_enabled	= sprd_gate_is_enabled,
+};
+EXPORT_SYMBOL_GPL(sprd_gate_ops);
+
+const struct clk_ops sprd_sc_gate_ops = {
+	.disable	= sprd_sc_gate_disable,
+	.enable		= sprd_sc_gate_enable,
+	.is_enabled	= sprd_gate_is_enabled,
+};
+EXPORT_SYMBOL_GPL(sprd_sc_gate_ops);
+
+const struct clk_ops sprd_pll_sc_gate_ops = {
+	.unprepare	= sprd_sc_gate_disable,
+	.prepare	= sprd_pll_sc_gate_prepare,
+	.is_enabled	= sprd_gate_is_enabled,
+};
+EXPORT_SYMBOL_GPL(sprd_pll_sc_gate_ops);