[PATCH 19/21] soundwire: amd: Cancel pending work before suspending manager

[Lee Jones <lee@kernel.org>]

amd_suspend_runtime() stops the SoundWire bus clock and transitions the
controller into D3 without cancelling amd_sdw_irq_thread and
amd_sdw_work, and amd_suspend() only cancels amd_sdw_work without first
cancelling amd_sdw_irq_thread.  Queued work executing concurrently with
suspend can access MMIO registers after the controller is clock-stopped
or powered down.

Mask manager interrupts, synchronise the parent PCI IRQ, and cancel both
amd_sdw_irq_thread and amd_sdw_work before stopping the bus clock and in
amd_deinit_sdw_manager(), unmask wake interrupts only after clock stop
completes, and avoid non-wake register accesses in amd_sdw_irq_thread()
while the clock is stopped.

Fixes: 81ff58ff71ad ("soundwire: amd: add runtime pm ops for AMD SoundWire manager driver")
Closes: https://sashiko.dev/#/bug/linux-3b774ace-00cf-41e6-82eb-85cd43f5e1d6
Cc: stable@vger.kernel.org
Signed-off-by: Lee Jones <lee@kernel.org>
---
 drivers/soundwire/amd_manager.c | 40 ++++++++++++++++++++++++++++-----
 1 file changed, 34 insertions(+), 6 deletions(-)

diff --git a/drivers/soundwire/amd_manager.c b/drivers/soundwire/amd_manager.c
index f39f4f04db7e..ba8e6d42c467 100644
--- a/drivers/soundwire/amd_manager.c
+++ b/drivers/soundwire/amd_manager.c
@@ -148,9 +148,24 @@ static void amd_disable_sdw_interrupts(struct amd_sdw_manager *amd_manager)
 	writel(0x00, amd_manager->mmio + ACP_SW_ERROR_INTR_MASK);
 }
 
+static void amd_sdw_quiesce_work(struct amd_sdw_manager *amd_manager)
+{
+	struct device *parent = amd_manager->dev->parent;
+
+	disable_work_sync(&amd_manager->amd_sdw_work);
+	writel(0, amd_manager->mmio + ACP_SW_STATE_CHANGE_STATUS_MASK_0TO7);
+	writel(0, amd_manager->mmio + ACP_SW_STATE_CHANGE_STATUS_MASK_8TO11);
+	writel(0, amd_manager->mmio + ACP_SW_ERROR_INTR_MASK);
+	if (parent && dev_is_pci(parent))
+		synchronize_irq(to_pci_dev(parent)->irq);
+	cancel_work_sync(&amd_manager->amd_sdw_irq_thread);
+	enable_work(&amd_manager->amd_sdw_work);
+}
+
 static int amd_deinit_sdw_manager(struct amd_sdw_manager *amd_manager)
 {
 	amd_disable_sdw_interrupts(amd_manager);
+	amd_sdw_quiesce_work(amd_manager);
 	return amd_disable_sdw_manager(amd_manager);
 }
 
@@ -1049,6 +1064,14 @@ static void amd_sdw_irq_thread(struct work_struct *work)
 	u32 status_change_8to11;
 	u32 status_change_0to7;
 
+	if (amd_manager->clk_stopped) {
+		status_change_8to11 = readl(amd_manager->mmio +
+					    ACP_SW_STATE_CHANGE_STATUS_8TO11);
+		if (status_change_8to11 & AMD_SDW_WAKE_STAT_MASK)
+			amd_sdw_process_wake_event(amd_manager);
+		return;
+	}
+
 	status_change_8to11 = readl(amd_manager->mmio + ACP_SW_STATE_CHANGE_STATUS_8TO11);
 	status_change_0to7 = readl(amd_manager->mmio + ACP_SW_STATE_CHANGE_STATUS_0TO7);
 	if (!status_change_0to7 && !status_change_8to11)
@@ -1341,24 +1364,24 @@ static int __maybe_unused amd_suspend(struct device *dev)
 	}
 
 	if (amd_manager->power_mode_mask & AMD_SDW_CLK_STOP_MODE) {
-		cancel_work_sync(&amd_manager->amd_sdw_work);
-		amd_sdw_wake_enable(amd_manager, false);
 		if (amd_manager->acp_rev >= ACP70_PCI_REV_ID) {
 			ret = amd_sdw_host_wake_enable(amd_manager, false);
 			if (ret)
 				return ret;
 		}
+		amd_sdw_quiesce_work(amd_manager);
+		amd_sdw_wake_enable(amd_manager, false);
 		ret = amd_sdw_clock_stop(amd_manager);
 		if (ret)
 			return ret;
 	} else if (amd_manager->power_mode_mask & AMD_SDW_POWER_OFF_MODE) {
-		cancel_work_sync(&amd_manager->amd_sdw_work);
-		amd_sdw_wake_enable(amd_manager, false);
 		if (amd_manager->acp_rev >= ACP70_PCI_REV_ID) {
 			ret = amd_sdw_host_wake_enable(amd_manager, false);
 			if (ret)
 				return ret;
 		}
+		amd_sdw_quiesce_work(amd_manager);
+		amd_sdw_wake_enable(amd_manager, false);
 		/*
 		 * As per hardware programming sequence on AMD platforms,
 		 * clock stop should be invoked first before powering-off
@@ -1391,25 +1414,29 @@ static int __maybe_unused amd_suspend_runtime(struct device *dev)
 		return 0;
 	}
 	if (amd_manager->power_mode_mask & AMD_SDW_CLK_STOP_MODE) {
-		amd_sdw_wake_enable(amd_manager, true);
 		if (amd_manager->acp_rev >= ACP70_PCI_REV_ID) {
 			ret = amd_sdw_host_wake_enable(amd_manager, true);
 			if (ret)
 				return ret;
 		}
+		amd_sdw_quiesce_work(amd_manager);
 		ret = amd_sdw_clock_stop(amd_manager);
 		if (ret)
 			return ret;
+		if (amd_manager->clk_stopped)
+			amd_sdw_wake_enable(amd_manager, true);
 	} else if (amd_manager->power_mode_mask & AMD_SDW_POWER_OFF_MODE) {
-		amd_sdw_wake_enable(amd_manager, true);
 		if (amd_manager->acp_rev >= ACP70_PCI_REV_ID) {
 			ret = amd_sdw_host_wake_enable(amd_manager, true);
 			if (ret)
 				return ret;
 		}
+		amd_sdw_quiesce_work(amd_manager);
 		ret = amd_sdw_clock_stop(amd_manager);
 		if (ret)
 			return ret;
+		if (amd_manager->clk_stopped)
+			amd_sdw_wake_enable(amd_manager, true);
 		ret = amd_deinit_sdw_manager(amd_manager);
 		if (ret)
 			return ret;
@@ -1452,6 +1479,7 @@ static int __maybe_unused amd_resume_runtime(struct device *dev)
 			if (ret)
 				return ret;
 		}
+		amd_enable_sdw_interrupts(amd_manager);
 	} else if (amd_manager->power_mode_mask & AMD_SDW_POWER_OFF_MODE) {
 		writel(0x00, amd_manager->acp_mmio + ACP_SW_WAKE_EN(amd_manager->instance));
 		if (amd_manager->acp_rev >= ACP70_PCI_REV_ID) {
-- 
2.56.0.317.g454f8302e1-goog