[PATCH] soundwire: qcom: quiesce runtime PM before removing bus

[Myeonghun Pak <mhun512@gmail.com>]

Qualcomm SoundWire controllers enable runtime PM after registering the bus,
but remove tears down the bus and iface clock while runtime callbacks and
the main or optional in-band wake IRQ handlers can still run. A controller
that is already runtime-suspended also has its iface clock disabled, so the
unconditional clock disable in remove unbalances that clock.

Disable runtime PM first to cancel pending requests and drain any callback.
Free both controller IRQs synchronously before deleting SoundWire children,
then disable the iface clock only when runtime suspend has not already done
so. Record the powered-down state for a later rebind. Bus deletion does not
require a resume: the Qualcomm master has no put_device_num operation. The
core disables slave runtime PM before unregistering each SoundWire child.

A pending runtime resume can run while runtime PM is being disabled. Make
its clock enable failure visible to the PM core and restore the wake IRQ in
that case, so the runtime status continues to describe the clock state.

This issue was identified during our ongoing static-analysis research while
reviewing kernel code.

Fixes: 74e79da9fd46 ("soundwire: qcom: add runtime pm support")
Cc: stable@vger.kernel.org
Assisted-by: OpenAI:GPT-5.6
Co-developed-by: Ijae Kim <ae878000@gmail.com>
Signed-off-by: Ijae Kim <ae878000@gmail.com>
Signed-off-by: Myeonghun Pak <mhun512@gmail.com>
---
 drivers/soundwire/qcom.c | 27 +++++++++++++++++++++++----
 1 file changed, 23 insertions(+), 4 deletions(-)

diff --git a/drivers/soundwire/qcom.c b/drivers/soundwire/qcom.c
index 55678a30c..35e552cc0 100644
--- a/drivers/soundwire/qcom.c
+++ b/drivers/soundwire/qcom.c
@@ -1713,23 +1713,42 @@ static int qcom_swrm_probe(struct platform_device *pdev)
 
 static void qcom_swrm_remove(struct platform_device *pdev)
 {
-	struct qcom_swrm_ctrl *ctrl = dev_get_drvdata(&pdev->dev);
+	struct device *dev = &pdev->dev;
+	struct qcom_swrm_ctrl *ctrl = dev_get_drvdata(dev);
+	bool suspended;
+
+	pm_runtime_disable(dev);
+	suspended = pm_runtime_status_suspended(dev);
+
+	devm_free_irq(dev, ctrl->irq, ctrl);
+	if (ctrl->wake_irq > 0)
+		devm_free_irq(dev, ctrl->wake_irq, ctrl);
 
 	sdw_bus_master_delete(&ctrl->bus);
-	clk_disable_unprepare(ctrl->hclk);
+	if (!suspended)
+		clk_disable_unprepare(ctrl->hclk);
+	pm_runtime_set_suspended(dev);
 }
 
 static int __maybe_unused swrm_runtime_resume(struct device *dev)
 {
 	struct qcom_swrm_ctrl *ctrl = dev_get_drvdata(dev);
+	bool wake_irq_disabled = false;
 	int ret;
 
 	if (ctrl->wake_irq > 0) {
-		if (!irqd_irq_disabled(irq_get_irq_data(ctrl->wake_irq)))
+		if (!irqd_irq_disabled(irq_get_irq_data(ctrl->wake_irq))) {
 			disable_irq_nosync(ctrl->wake_irq);
+			wake_irq_disabled = true;
+		}
 	}
 
-	clk_prepare_enable(ctrl->hclk);
+	ret = clk_prepare_enable(ctrl->hclk);
+	if (ret) {
+		if (wake_irq_disabled)
+			enable_irq(ctrl->wake_irq);
+		return ret;
+	}
 
 	if (ctrl->clock_stop_not_supported) {
 		reinit_completion(&ctrl->enumeration);