openwrt/target/linux/bcm27xx/patches-5.10/950-0675-drm-vc4-hdmi-Drop-devm-interrupt-handler-for-CEC-int.patch

From 687a0fc86f37e0bc74c8382c0d89b0929fade1de Mon Sep 17 00:00:00 2001
From: Maxime Ripard <maxime@cerno.tech>
Date: Mon, 5 Jul 2021 15:47:43 +0200
Subject: [PATCH] drm/vc4: hdmi: Drop devm interrupt handler for CEC
 interrupts

The CEC interrupt handlers are registered through the
devm_request_threaded_irq function. However, while free_irq is indeed
called properly when the device is unbound or bind fails, it's called
after unbind or bind is done.

In our particular case, it means that on failure it creates a window
where our interrupt handler can be called, but we're freeing every
resource (CEC adapter, DRM objects, etc.) it might need.

In order to address this, let's switch to the non-devm variant to
control better when the handler will be unregistered and allow us to
make it safe.

Fixes: 15b4511a4af6 ("drm/vc4: add HDMI CEC support")
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
---
 drivers/gpu/drm/vc4/vc4_hdmi.c | 49 +++++++++++++++++++++++-----------
 1 file changed, 33 insertions(+), 16 deletions(-)

--- a/drivers/gpu/drm/vc4/vc4_hdmi.c
+++ b/drivers/gpu/drm/vc4/vc4_hdmi.c
@@ -1896,25 +1896,23 @@ static int vc4_hdmi_cec_init(struct vc4_
 	vc4_hdmi_cec_update_clk_div(vc4_hdmi);
 
 	if (vc4_hdmi->variant->external_irq_controller) {
-		ret = devm_request_threaded_irq(&pdev->dev,
-						platform_get_irq_byname(pdev, "cec-rx"),
+		ret = request_threaded_irq(platform_get_irq_byname(pdev, "cec-rx"),
 						vc4_cec_irq_handler_rx_bare,
 						vc4_cec_irq_handler_rx_thread, 0,
 						"vc4 hdmi cec rx", vc4_hdmi);
 		if (ret)
 			goto err_delete_cec_adap;
 
-		ret = devm_request_threaded_irq(&pdev->dev,
-						platform_get_irq_byname(pdev, "cec-tx"),
+		ret = request_threaded_irq(platform_get_irq_byname(pdev, "cec-tx"),
 						vc4_cec_irq_handler_tx_bare,
 						vc4_cec_irq_handler_tx_thread, 0,
 						"vc4 hdmi cec tx", vc4_hdmi);
 		if (ret)
-			goto err_delete_cec_adap;
+			goto err_remove_cec_rx_handler;
 	} else {
 		HDMI_WRITE(HDMI_CEC_CPU_MASK_SET, 0xffffffff);
 
-		ret = devm_request_threaded_irq(&pdev->dev, platform_get_irq(pdev, 0),
+		ret = request_threaded_irq(platform_get_irq(pdev, 0),
 						vc4_cec_irq_handler,
 						vc4_cec_irq_handler_thread, 0,
 						"vc4 hdmi cec", vc4_hdmi);
@@ -1924,10 +1922,20 @@ static int vc4_hdmi_cec_init(struct vc4_
 
 	ret = cec_register_adapter(vc4_hdmi->cec_adap, &pdev->dev);
 	if (ret < 0)
-		goto err_delete_cec_adap;
+		goto err_remove_handlers;
 
 	return 0;
 
+err_remove_handlers:
+	if (vc4_hdmi->variant->external_irq_controller)
+		free_irq(platform_get_irq_byname(pdev, "cec-tx"), vc4_hdmi);
+	else
+		free_irq(platform_get_irq(pdev, 0), vc4_hdmi);
+
+err_remove_cec_rx_handler:
+	if (vc4_hdmi->variant->external_irq_controller)
+		free_irq(platform_get_irq_byname(pdev, "cec-rx"), vc4_hdmi);
+
 err_delete_cec_adap:
 	cec_delete_adapter(vc4_hdmi->cec_adap);
 
@@ -1936,6 +1944,15 @@ err_delete_cec_adap:
 
 static void vc4_hdmi_cec_exit(struct vc4_hdmi *vc4_hdmi)
 {
+	struct platform_device *pdev = vc4_hdmi->pdev;
+
+	if (vc4_hdmi->variant->external_irq_controller) {
+		free_irq(platform_get_irq_byname(pdev, "cec-rx"), vc4_hdmi);
+		free_irq(platform_get_irq_byname(pdev, "cec-tx"), vc4_hdmi);
+	} else {
+		free_irq(platform_get_irq(pdev, 0), vc4_hdmi);
+	}
+
 	cec_unregister_adapter(vc4_hdmi->cec_adap);
 }
 #else