[PATCH v6 08/14] drm/tegra: Allocate per-engine channel in core code

[Mikko Perttunen <mperttunen@nvidia.com>]

To avoid code duplication, allocate the per-engine shared channel in
the core code instead. This is the usual channel that all jobs are
submitted to when MLOCKing is not in use. 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@nvidia.com>
---
v6:
- Reorder fields in drm.h to put core-controlled fields first
---
 drivers/gpu/drm/tegra/drm.c | 11 +++++++++++
 drivers/gpu/drm/tegra/drm.h |  2 ++
 2 files changed, 13 insertions(+)

diff --git a/drivers/gpu/drm/tegra/drm.c b/drivers/gpu/drm/tegra/drm.c
index c9a35c1dc970..a27e5a89d676 100644
--- a/drivers/gpu/drm/tegra/drm.c
+++ b/drivers/gpu/drm/tegra/drm.c
@@ -869,6 +869,14 @@ static const 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;
@@ -885,6 +893,9 @@ 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 f38de08e0c95..1ec07034727c 100644
--- a/drivers/gpu/drm/tegra/drm.h
+++ b/drivers/gpu/drm/tegra/drm.h
@@ -86,7 +86,9 @@ struct tegra_drm_client {
 	struct host1x_client base;
 	struct list_head list;
 	struct tegra_drm *drm;
+	struct host1x_channel *shared_channel;
 
+	/* Set by driver */
 	unsigned int version;
 	const struct tegra_drm_client_ops *ops;
 };
-- 
2.30.1