[PATCH v4 18/21] drm/tegra: Allocate per-engine channel in core code

[Mikko Perttunen]

To avoid duplication, allocate the per-engine shared channel in the
core code instead. Once MLOCKs are implemented on Host1x side, we
can also update this to avoid allocating a shared channel when
MLOCKs are enabled.

Signed-off-by: Mikko Perttunen <mperttunen at nvidia.com>
---
 drivers/gpu/drm/tegra/drm.c | 11 +++++++++++
 drivers/gpu/drm/tegra/drm.h |  4 ++++
 2 files changed, 15 insertions(+)

diff --git a/drivers/gpu/drm/tegra/drm.c b/drivers/gpu/drm/tegra/drm.c
index 7437c67924aa..7124b0b0154b 100644
--- a/drivers/gpu/drm/tegra/drm.c
+++ b/drivers/gpu/drm/tegra/drm.c
@@ -887,6 +887,14 @@ static struct drm_driver tegra_drm_driver = {
 int tegra_drm_register_client(struct tegra_drm *tegra,
 			      struct tegra_drm_client *client)
 {
+	/*
+	 * When MLOCKs are implemented, change to allocate a shared channel
+	 * only when MLOCKs are disabled.
+	 */
+	client->shared_channel = host1x_channel_request(&client->base);
+	if (!client->shared_channel)
+		return -EBUSY;
+
 	mutex_lock(&tegra->clients_lock);
 	list_add_tail(&client->list, &tegra->clients);
 	client->drm = tegra;
@@ -903,6 +911,9 @@ int tegra_drm_unregister_client(struct tegra_drm *tegra,
 	client->drm = NULL;
 	mutex_unlock(&tegra->clients_lock);
 
+	if (client->shared_channel)
+		host1x_channel_put(client->shared_channel);
+
 	return 0;
 }
 
diff --git a/drivers/gpu/drm/tegra/drm.h b/drivers/gpu/drm/tegra/drm.h
index b25443255be6..3fc42fd97911 100644
--- a/drivers/gpu/drm/tegra/drm.h
+++ b/drivers/gpu/drm/tegra/drm.h
@@ -86,8 +86,12 @@ struct tegra_drm_client {
 	struct list_head list;
 	struct tegra_drm *drm;
 
+	/* Set by driver */
 	unsigned int version;
 	const struct tegra_drm_client_ops *ops;
+
+	/* Set by TegraDRM core */
+	struct host1x_channel *shared_channel;
 };
 
 static inline struct tegra_drm_client *
-- 
2.29.2