linux-kernel - [PATCH v2 2/4] drm/tegra: Create DRM device early

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Message-Id: <20211130230957.30213-3-digetx@gmail.com>
Date:   Wed,  1 Dec 2021 02:09:55 +0300
From:   Dmitry Osipenko <digetx@...il.com>
To:     Thierry Reding <thierry.reding@...il.com>,
        Jonathan Hunter <jonathanh@...dia.com>,
        Lyude Paul <lyude@...hat.com>, David Airlie <airlied@...ux.ie>,
        Daniel Vetter <daniel@...ll.ch>,
        Thomas Graichen <thomas.graichen@...il.com>
Cc:     dri-devel@...ts.freedesktop.org, linux-tegra@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: [PATCH v2 2/4] drm/tegra: Create DRM device early

DRM sub-drivers need to access DRM device early during first stage of
drivers' probing. Use new host1x init/deinit callbacks to create DRM
device early and destroy late.

Cc: <stable@...r.kernel.org> # 5.13+
Signed-off-by: Dmitry Osipenko <digetx@...il.com>
---
 drivers/gpu/drm/tegra/drm.c | 46 ++++++++++++++++++++++++++-----------
 drivers/gpu/drm/tegra/drm.h |  2 ++
 2 files changed, 35 insertions(+), 13 deletions(-)

diff --git a/drivers/gpu/drm/tegra/drm.c b/drivers/gpu/drm/tegra/drm.c
index e9de91a4e7e8..e9cbcaf6e017 100644
--- a/drivers/gpu/drm/tegra/drm.c
+++ b/drivers/gpu/drm/tegra/drm.c
@@ -1133,21 +1133,42 @@ static bool host1x_drm_wants_iommu(struct host1x_device *dev)
 	return domain != NULL;
 }
 
-static int host1x_drm_probe(struct host1x_device *dev)
+static struct drm_device *terga_drm_dev;
+
+struct drm_device *tegra_drm_device(void)
 {
-	struct tegra_drm *tegra;
-	struct drm_device *drm;
-	int err;
+	return terga_drm_dev;
+}
 
-	drm = drm_dev_alloc(&tegra_drm_driver, &dev->dev);
+static int host1x_drm_dev_init(struct host1x_device *dev)
+{
+	struct drm_device *drm = drm_dev_alloc(&tegra_drm_driver, &dev->dev);
 	if (IS_ERR(drm))
 		return PTR_ERR(drm);
 
+	dev_set_drvdata(&dev->dev, drm);
+	terga_drm_dev = drm;
+
+	return 0;
+}
+
+static void host1x_drm_dev_deinit(struct host1x_device *dev)
+{
+	struct drm_device *drm = dev_get_drvdata(&dev->dev);
+
+	terga_drm_dev = NULL;
+	drm_dev_put(drm);
+}
+
+static int host1x_drm_probe(struct host1x_device *dev)
+{
+	struct drm_device *drm = dev_get_drvdata(&dev->dev);
+	struct tegra_drm *tegra;
+	int err;
+
 	tegra = kzalloc(sizeof(*tegra), GFP_KERNEL);
-	if (!tegra) {
-		err = -ENOMEM;
-		goto put;
-	}
+	if (!tegra)
+		return -ENOMEM;
 
 	if (host1x_drm_wants_iommu(dev) && iommu_present(&platform_bus_type)) {
 		tegra->domain = iommu_domain_alloc(&platform_bus_type);
@@ -1164,7 +1185,6 @@ static int host1x_drm_probe(struct host1x_device *dev)
 	mutex_init(&tegra->clients_lock);
 	INIT_LIST_HEAD(&tegra->clients);
 
-	dev_set_drvdata(&dev->dev, drm);
 	drm->dev_private = tegra;
 	tegra->drm = drm;
 
@@ -1285,8 +1305,7 @@ static int host1x_drm_probe(struct host1x_device *dev)
 		iommu_domain_free(tegra->domain);
 free:
 	kfree(tegra);
-put:
-	drm_dev_put(drm);
+
 	return err;
 }
 
@@ -1319,7 +1338,6 @@ static int host1x_drm_remove(struct host1x_device *dev)
 	}
 
 	kfree(tegra);
-	drm_dev_put(drm);
 
 	return 0;
 }
@@ -1391,6 +1409,8 @@ static struct host1x_driver host1x_drm_driver = {
 	.probe = host1x_drm_probe,
 	.remove = host1x_drm_remove,
 	.subdevs = host1x_drm_subdevs,
+	.init = host1x_drm_dev_init,
+	.deinit = host1x_drm_dev_deinit,
 };
 
 static struct platform_driver * const drivers[] = {
diff --git a/drivers/gpu/drm/tegra/drm.h b/drivers/gpu/drm/tegra/drm.h
index fc0a19554eac..8b7c9508070f 100644
--- a/drivers/gpu/drm/tegra/drm.h
+++ b/drivers/gpu/drm/tegra/drm.h
@@ -121,6 +121,8 @@ int tegra_drm_unregister_client(struct tegra_drm *tegra,
 int host1x_client_iommu_attach(struct host1x_client *client);
 void host1x_client_iommu_detach(struct host1x_client *client);
 
+struct drm_device *tegra_drm_device(void);
+
 int tegra_drm_init(struct tegra_drm *tegra, struct drm_device *drm);
 int tegra_drm_exit(struct tegra_drm *tegra);
 
-- 
2.33.1