[PATCH 4/5] drm/vc4: Notify the firmware when DRM is in charge

From: Maxime Ripard <maxime@cerno.tech>
To: Scott Branden <sbranden@broadcom.com>,
	Nicolas Saenz Julienne <nsaenz@kernel.org>,
	Rob Herring <robh+dt@kernel.org>,
	Frank Rowand <frowand.list@gmail.com>,
	Ray Jui <rjui@broadcom.com>,
	Florian Fainelli <f.fainelli@gmail.com>,
	Daniel Vetter <daniel.vetter@intel.com>,
	David Airlie <airlied@linux.ie>,
	Maarten Lankhorst <maarten.lankhorst@linux.intel.com>,
	Thomas Zimmermann <tzimmermann@suse.de>,
	Maxime Ripard <maxime@cerno.tech>
Cc: linux-rpi-kernel@lists.infradead.org,
	dri-devel@lists.freedesktop.org,
	linux-arm-kernel@lists.infradead.org,
	Dave Stevenson <dave.stevenson@raspberrypi.com>,
	Phil Elwell <phil@raspberrypi.com>,
	Tim Gover <tim.gover@raspberrypi.com>,
	Dom Cobley <dom@raspberrypi.com>,
	devicetree@vger.kernel.org,
	bcm-kernel-feedback-list@broadcom.com
Subject: [PATCH 4/5] drm/vc4: Notify the firmware when DRM is in charge
Date: Wed, 17 Nov 2021 15:50:39 +0100	[thread overview]
Message-ID: <20211117145040.334827-5-maxime@cerno.tech> (raw)
In-Reply-To: <20211117145040.334827-1-maxime@cerno.tech>

Once the call to drm_fb_helper_remove_conflicting_framebuffers() has
been made, simplefb has been unregistered and the KMS driver is entirely
in charge of the display.

Thus, we can notify the firmware it can free whatever resource it was
using to maintain simplefb functional.

Signed-off-by: Maxime Ripard <maxime@cerno.tech>
---
 drivers/gpu/drm/vc4/vc4_drv.c | 19 +++++++++++++++++++
 drivers/gpu/drm/vc4/vc4_drv.h |  2 ++
 2 files changed, 21 insertions(+)

diff --git a/drivers/gpu/drm/vc4/vc4_drv.c b/drivers/gpu/drm/vc4/vc4_drv.c
index 8ab89f805826..d09fa9c130da 100644
--- a/drivers/gpu/drm/vc4/vc4_drv.c
+++ b/drivers/gpu/drm/vc4/vc4_drv.c
@@ -37,6 +37,8 @@
 #include <drm/drm_fb_helper.h>
 #include <drm/drm_vblank.h>
 
+#include <soc/bcm2835/raspberrypi-firmware.h>
+
 #include "uapi/drm/vc4_drm.h"
 
 #include "vc4_drv.h"
@@ -251,10 +253,27 @@ static int vc4_drm_bind(struct device *dev)
 	if (ret)
 		return ret;
 
+	node = of_parse_phandle(dev->of_node, "raspberrypi,firmware", 0);
+	if (node) {
+		vc4->firmware = rpi_firmware_get(node);
+		of_node_put(node);
+
+		if (!vc4->firmware)
+			return -EPROBE_DEFER;
+	}
+
 	ret = drm_aperture_remove_framebuffers(false, &vc4_drm_driver);
 	if (ret)
 		return ret;
 
+	if (vc4->firmware) {
+		ret = rpi_firmware_property(vc4->firmware,
+					    RPI_FIRMWARE_NOTIFY_DISPLAY_DONE,
+					    NULL, 0);
+		if (ret)
+			drm_warn(drm, "Couldn't stop firmware display driver: %d\n", ret);
+	}
+
 	ret = component_bind_all(dev, drm);
 	if (ret)
 		return ret;
diff --git a/drivers/gpu/drm/vc4/vc4_drv.h b/drivers/gpu/drm/vc4/vc4_drv.h
index 4329e09d357c..b840654c53a9 100644
--- a/drivers/gpu/drm/vc4/vc4_drv.h
+++ b/drivers/gpu/drm/vc4/vc4_drv.h
@@ -76,6 +76,8 @@ struct vc4_dev {
 
 	unsigned int irq;
 
+	struct rpi_firmware *firmware;
+
 	struct vc4_hvs *hvs;
 	struct vc4_v3d *v3d;
 	struct vc4_dpi *dpi;
-- 
2.33.1

