From:   Neil Armstrong <narmstrong@baylibre.com>
To:     tomba@kernel.org
Cc:     linux-omap@vger.kernel.org, dri-devel@lists.freedesktop.org,
        linux-kernel@vger.kernel.org, khilman@baylibre.com,
        Benoit Parrot <bparrot@ti.com>,
        Neil Armstrong <narmstrong@baylibre.com>
Subject: [PATCH v7 6/9] drm/omap: Add global state as a private atomic object
Date:   Wed, 17 Nov 2021 15:19:25 +0100
Message-Id: <20211117141928.771082-7-narmstrong@baylibre.com>
In-Reply-To: <20211117141928.771082-1-narmstrong@baylibre.com>
References: <20211117141928.771082-1-narmstrong@baylibre.com>
MIME-Version: 1.0
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From: Benoit Parrot <bparrot@ti.com>

Global shared resources (like hw overlays) for omapdrm are implemented
as a part of atomic state using the drm_private_obj infrastructure
available in the atomic core.

omap_global_state is introduced as a drm atomic private object. The two
funcs omap_get_global_state() and omap_get_existing_global_state() are
the two variants that will be used to access omap_global_state.

drm_mode_config_init() needs to be called earlier because it
creates/initializes the private_obj link list maintained by the atomic
framework. The private_obj link list has to exist prior to calling
drm_atomic_private_obj_init(). Similarly the cleanup handler are
reordered appropriately.

Signed-off-by: Benoit Parrot <bparrot@ti.com>
Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
---
 drivers/gpu/drm/omapdrm/omap_drv.c | 91 +++++++++++++++++++++++++++++-
 drivers/gpu/drm/omapdrm/omap_drv.h | 17 ++++++
 2 files changed, 105 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/omapdrm/omap_drv.c b/drivers/gpu/drm/omapdrm/omap_drv.c
index f17a72a4023e..44a9dcb3100c 100644
--- a/drivers/gpu/drm/omapdrm/omap_drv.c
+++ b/drivers/gpu/drm/omapdrm/omap_drv.c
@@ -128,6 +128,82 @@ static const struct drm_mode_config_funcs omap_mode_config_funcs = {
 	.atomic_commit = drm_atomic_helper_commit,
 };
 
+/* Global/shared object state funcs */
+
+/*
+ * This is a helper that returns the private state currently in operation.
+ * Note that this would return the "old_state" if called in the atomic check
+ * path, and the "new_state" after the atomic swap has been done.
+ */
+struct omap_global_state *
+omap_get_existing_global_state(struct omap_drm_private *priv)
+{
+	return to_omap_global_state(priv->glob_obj.state);
+}
+
+/*
+ * This acquires the modeset lock set aside for global state, creates
+ * a new duplicated private object state.
+ */
+struct omap_global_state *__must_check
+omap_get_global_state(struct drm_atomic_state *s)
+{
+	struct omap_drm_private *priv = s->dev->dev_private;
+	struct drm_private_state *priv_state;
+
+	priv_state = drm_atomic_get_private_obj_state(s, &priv->glob_obj);
+	if (IS_ERR(priv_state))
+		return ERR_CAST(priv_state);
+
+	return to_omap_global_state(priv_state);
+}
+
+static struct drm_private_state *
+omap_global_duplicate_state(struct drm_private_obj *obj)
+{
+	struct omap_global_state *state;
+
+	state = kmemdup(obj->state, sizeof(*state), GFP_KERNEL);
+	if (!state)
+		return NULL;
+
+	__drm_atomic_helper_private_obj_duplicate_state(obj, &state->base);
+
+	return &state->base;
+}
+
+static void omap_global_destroy_state(struct drm_private_obj *obj,
+				      struct drm_private_state *state)
+{
+	struct omap_global_state *omap_state = to_omap_global_state(state);
+
+	kfree(omap_state);
+}
+
+static const struct drm_private_state_funcs omap_global_state_funcs = {
+	.atomic_duplicate_state = omap_global_duplicate_state,
+	.atomic_destroy_state = omap_global_destroy_state,
+};
+
+static int omap_global_obj_init(struct drm_device *dev)
+{
+	struct omap_drm_private *priv = dev->dev_private;
+	struct omap_global_state *state;
+
+	state = kzalloc(sizeof(*state), GFP_KERNEL);
+	if (!state)
+		return -ENOMEM;
+
+	drm_atomic_private_obj_init(dev, &priv->glob_obj, &state->base,
+				    &omap_global_state_funcs);
+	return 0;
+}
+
+static void omap_global_obj_fini(struct omap_drm_private *priv)
+{
+	drm_atomic_private_obj_fini(&priv->glob_obj);
+}
+
 static void omap_disconnect_pipelines(struct drm_device *ddev)
 {
 	struct omap_drm_private *priv = ddev->dev_private;
@@ -231,8 +307,6 @@ static int omap_modeset_init(struct drm_device *dev)
 	if (!omapdss_stack_is_ready())
 		return -EPROBE_DEFER;
 
-	drm_mode_config_init(dev);
-
 	ret = omap_modeset_init_properties(dev);
 	if (ret < 0)
 		return ret;
@@ -583,10 +657,16 @@ static int omapdrm_init(struct omap_drm_private *priv, struct device *dev)
 
 	omap_gem_init(ddev);
 
-	ret = omap_hwoverlays_init(priv);
+	drm_mode_config_init(ddev);
+
+	ret = omap_global_obj_init(ddev);
 	if (ret)
 		goto err_gem_deinit;
 
+	ret = omap_hwoverlays_init(priv);
+	if (ret)
+		goto err_free_priv_obj;
+
 	ret = omap_modeset_init(ddev);
 	if (ret) {
 		dev_err(priv->dev, "omap_modeset_init failed: ret=%d\n", ret);
@@ -624,7 +704,10 @@ static int omapdrm_init(struct omap_drm_private *priv, struct device *dev)
 	omap_modeset_fini(ddev);
 err_free_overlays:
 	omap_hwoverlays_destroy(priv);
+err_free_priv_obj:
+	omap_global_obj_fini(priv);
 err_gem_deinit:
+	drm_mode_config_cleanup(ddev);
 	omap_gem_deinit(ddev);
 	destroy_workqueue(priv->wq);
 	omap_disconnect_pipelines(ddev);
@@ -649,6 +732,8 @@ static void omapdrm_cleanup(struct omap_drm_private *priv)
 
 	omap_modeset_fini(ddev);
 	omap_hwoverlays_destroy(priv);
+	omap_global_obj_fini(priv);
+	drm_mode_config_cleanup(ddev);
 	omap_gem_deinit(ddev);
 
 	destroy_workqueue(priv->wq);
diff --git a/drivers/gpu/drm/omapdrm/omap_drv.h b/drivers/gpu/drm/omapdrm/omap_drv.h
index b4d9c2062723..a3079aad7ae3 100644
--- a/drivers/gpu/drm/omapdrm/omap_drv.h
+++ b/drivers/gpu/drm/omapdrm/omap_drv.h
@@ -14,6 +14,7 @@
 #include "dss/omapdss.h"
 #include "dss/dss.h"
 
+#include <drm/drm_atomic.h>
 #include <drm/drm_gem.h>
 #include <drm/omap_drm.h>
 
@@ -41,6 +42,16 @@ struct omap_drm_pipeline {
 	unsigned int alias_id;
 };
 
+/*
+ * Global private object state for tracking resources that are shared across
+ * multiple kms objects (planes/crtcs/etc).
+ */
+#define to_omap_global_state(x) container_of(x, struct omap_global_state, base)
+
+struct omap_global_state {
+	struct drm_private_state base;
+};
+
 struct omap_drm_private {
 	struct drm_device *ddev;
 	struct device *dev;
@@ -61,6 +72,8 @@ struct omap_drm_private {
 	unsigned int num_ovls;
 	struct omap_hw_overlay *overlays[8];
 
+	struct drm_private_obj glob_obj;
+
 	struct drm_fb_helper *fbdev;
 
 	struct workqueue_struct *wq;
@@ -89,4 +102,8 @@ struct omap_drm_private {
 
 void omap_debugfs_init(struct drm_minor *minor);
 
+struct omap_global_state * __must_check omap_get_global_state(struct drm_atomic_state *s);
+
+struct omap_global_state *omap_get_existing_global_state(struct omap_drm_private *priv);
+
 #endif /* __OMAPDRM_DRV_H__ */
-- 
2.25.1