[PATCH 6.6 005/638] media: rkisp1: Fix IRQ handling due to shared interrupts

[Sasha Levin]

From: Tomi Valkeinen <tomi.valkeinen@xxxxxxxxxxxxxxxx>

[ Upstream commit ffb635bb398fc07cb38f8a7b4a82cbe5f412f08e ]

The driver requests the interrupts as IRQF_SHARED, so the interrupt
handlers can be called at any time. If such a call happens while the ISP
is powered down, the SoC will hang as the driver tries to access the
ISP registers.

This can be reproduced even without the platform sharing the IRQ line:
Enable CONFIG_DEBUG_SHIRQ and unload the driver, and the board will
hang.

Fix this by adding a new field, 'irqs_enabled', which is used to bail
out from the interrupt handler when the ISP is not operational.

Link: https://lore.kernel.org/r/20231218-rkisp-shirq-fix-v1-2-173007628248@xxxxxxxxxxxxxxxx

Signed-off-by: Tomi Valkeinen <tomi.valkeinen@xxxxxxxxxxxxxxxx>
Signed-off-by: Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx>
Signed-off-by: Mauro Carvalho Chehab <mchehab@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 .../platform/rockchip/rkisp1/rkisp1-capture.c |  3 +++
 .../platform/rockchip/rkisp1/rkisp1-common.h  |  2 ++
 .../platform/rockchip/rkisp1/rkisp1-csi.c     |  3 +++
 .../platform/rockchip/rkisp1/rkisp1-dev.c     | 22 +++++++++++++++++++
 .../platform/rockchip/rkisp1/rkisp1-isp.c     |  3 +++
 5 files changed, 33 insertions(+)

diff --git a/drivers/media/platform/rockchip/rkisp1/rkisp1-capture.c b/drivers/media/platform/rockchip/rkisp1/rkisp1-capture.c
index 8f3cba3197623..c584bb6d31998 100644
--- a/drivers/media/platform/rockchip/rkisp1/rkisp1-capture.c
+++ b/drivers/media/platform/rockchip/rkisp1/rkisp1-capture.c
@@ -723,6 +723,9 @@ irqreturn_t rkisp1_capture_isr(int irq, void *ctx)
 	unsigned int i;
 	u32 status;
 
+	if (!rkisp1->irqs_enabled)
+		return IRQ_NONE;
+
 	status = rkisp1_read(rkisp1, RKISP1_CIF_MI_MIS);
 	if (!status)
 		return IRQ_NONE;
diff --git a/drivers/media/platform/rockchip/rkisp1/rkisp1-common.h b/drivers/media/platform/rockchip/rkisp1/rkisp1-common.h
index 104a1dbeff433..e9bc6c155d2fc 100644
--- a/drivers/media/platform/rockchip/rkisp1/rkisp1-common.h
+++ b/drivers/media/platform/rockchip/rkisp1/rkisp1-common.h
@@ -467,6 +467,7 @@ struct rkisp1_debug {
  * @debug:	   debug params to be exposed on debugfs
  * @info:	   version-specific ISP information
  * @irqs:          IRQ line numbers
+ * @irqs_enabled:  the hardware is enabled and can cause interrupts
  */
 struct rkisp1_device {
 	void __iomem *base_addr;
@@ -488,6 +489,7 @@ struct rkisp1_device {
 	struct rkisp1_debug debug;
 	const struct rkisp1_info *info;
 	int irqs[RKISP1_NUM_IRQS];
+	bool irqs_enabled;
 };
 
 /*
diff --git a/drivers/media/platform/rockchip/rkisp1/rkisp1-csi.c b/drivers/media/platform/rockchip/rkisp1/rkisp1-csi.c
index 0a67eb96402cb..1537dccbd2e28 100644
--- a/drivers/media/platform/rockchip/rkisp1/rkisp1-csi.c
+++ b/drivers/media/platform/rockchip/rkisp1/rkisp1-csi.c
@@ -211,6 +211,9 @@ irqreturn_t rkisp1_csi_isr(int irq, void *ctx)
 	struct rkisp1_device *rkisp1 = dev_get_drvdata(dev);
 	u32 val, status;
 
+	if (!rkisp1->irqs_enabled)
+		return IRQ_NONE;
+
 	status = rkisp1_read(rkisp1, RKISP1_CIF_MIPI_MIS);
 	if (!status)
 		return IRQ_NONE;
diff --git a/drivers/media/platform/rockchip/rkisp1/rkisp1-dev.c b/drivers/media/platform/rockchip/rkisp1/rkisp1-dev.c
index acc559652d6eb..73cf08a740118 100644
--- a/drivers/media/platform/rockchip/rkisp1/rkisp1-dev.c
+++ b/drivers/media/platform/rockchip/rkisp1/rkisp1-dev.c
@@ -305,6 +305,24 @@ static int __maybe_unused rkisp1_runtime_suspend(struct device *dev)
 {
 	struct rkisp1_device *rkisp1 = dev_get_drvdata(dev);
 
+	rkisp1->irqs_enabled = false;
+	/* Make sure the IRQ handler will see the above */
+	mb();
+
+	/*
+	 * Wait until any running IRQ handler has returned. The IRQ handler
+	 * may get called even after this (as it's a shared interrupt line)
+	 * but the 'irqs_enabled' flag will make the handler return immediately.
+	 */
+	for (unsigned int il = 0; il < ARRAY_SIZE(rkisp1->irqs); ++il) {
+		if (rkisp1->irqs[il] == -1)
+			continue;
+
+		/* Skip if the irq line is the same as previous */
+		if (il == 0 || rkisp1->irqs[il - 1] != rkisp1->irqs[il])
+			synchronize_irq(rkisp1->irqs[il]);
+	}
+
 	clk_bulk_disable_unprepare(rkisp1->clk_size, rkisp1->clks);
 	return pinctrl_pm_select_sleep_state(dev);
 }
@@ -321,6 +339,10 @@ static int __maybe_unused rkisp1_runtime_resume(struct device *dev)
 	if (ret)
 		return ret;
 
+	rkisp1->irqs_enabled = true;
+	/* Make sure the IRQ handler will see the above */
+	mb();
+
 	return 0;
 }
 
diff --git a/drivers/media/platform/rockchip/rkisp1/rkisp1-isp.c b/drivers/media/platform/rockchip/rkisp1/rkisp1-isp.c
index 2239fb6c7d393..8fc9c1c116f1d 100644
--- a/drivers/media/platform/rockchip/rkisp1/rkisp1-isp.c
+++ b/drivers/media/platform/rockchip/rkisp1/rkisp1-isp.c
@@ -1027,6 +1027,9 @@ irqreturn_t rkisp1_isp_isr(int irq, void *ctx)
 	struct rkisp1_device *rkisp1 = dev_get_drvdata(dev);
 	u32 status, isp_err;
 
+	if (!rkisp1->irqs_enabled)
+		return IRQ_NONE;
+
 	status = rkisp1_read(rkisp1, RKISP1_CIF_ISP_MIS);
 	if (!status)
 		return IRQ_NONE;
-- 
2.43.0