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, 59 insertions, 0 deletions

diff --git a/drivers/clk/qcom/reset.c b/drivers/clk/qcom/reset.c
new file mode 100644
index 000000000..d96c96a90
--- /dev/null
+++ b/drivers/clk/qcom/reset.c
@@ -0,0 +1,59 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (c) 2013, The Linux Foundation. All rights reserved.
+ */
+
+#include <linux/bitops.h>
+#include <linux/export.h>
+#include <linux/regmap.h>
+#include <linux/reset-controller.h>
+#include <linux/delay.h>
+
+#include "reset.h"
+
+static int qcom_reset(struct reset_controller_dev *rcdev, unsigned long id)
+{
+	struct qcom_reset_controller *rst = to_qcom_reset_controller(rcdev);
+
+	rcdev->ops->assert(rcdev, id);
+	fsleep(rst->reset_map[id].udelay ?: 1); /* use 1 us as default */
+
+	rcdev->ops->deassert(rcdev, id);
+	return 0;
+}
+
+static int qcom_reset_set_assert(struct reset_controller_dev *rcdev,
+				 unsigned long id, bool assert)
+{
+	struct qcom_reset_controller *rst;
+	const struct qcom_reset_map *map;
+	u32 mask;
+
+	rst = to_qcom_reset_controller(rcdev);
+	map = &rst->reset_map[id];
+	mask = map->bitmask ? map->bitmask : BIT(map->bit);
+
+	regmap_update_bits(rst->regmap, map->reg, mask, assert ? mask : 0);
+
+	/* Read back the register to ensure write completion, ignore the value */
+	regmap_read(rst->regmap, map->reg, &mask);
+
+	return 0;
+}
+
+static int qcom_reset_assert(struct reset_controller_dev *rcdev, unsigned long id)
+{
+	return qcom_reset_set_assert(rcdev, id, true);
+}
+
+static int qcom_reset_deassert(struct reset_controller_dev *rcdev, unsigned long id)
+{
+	return qcom_reset_set_assert(rcdev, id, false);
+}
+
+const struct reset_control_ops qcom_reset_ops = {
+	.reset = qcom_reset,
+	.assert = qcom_reset_assert,
+	.deassert = qcom_reset_deassert,
+};
+EXPORT_SYMBOL_GPL(qcom_reset_ops);