staging: mmal-vchiq: Allocate and free components as required

The existing code assumed that there would only ever be 4 components,
and never freed the entries once used.
Allow arbitrary creation and destruction of components.
Signed-off-by: Dave Stevenson <dave.stevenson@raspberrypi.org>
Signed-off-by: Jacopo Mondi <jacopo@jmondi.org>
Signed-off-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
Link: https://lore.kernel.org/r/20200623164235.29566-3-nsaenzjulienne@suse.deSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/vc04_services/vchiq-mmal/mmal-vchiq.c

@@ -32,8 +32,11 @@
 #define USE_VCHIQ_ARM
 #include "interface/vchi/vchi.h"
 
-/* maximum number of components supported */
-#define VCHIQ_MMAL_MAX_COMPONENTS 4
+/*
+ * maximum number of components supported.
+ * This matches the maximum permitted by default on the VPU
+ */
+#define VCHIQ_MMAL_MAX_COMPONENTS 64
 
 /*#define FULL_MSG_DUMP 1*/
 
@@ -168,8 +171,6 @@ struct vchiq_mmal_instance {
 	/* protect accesses to context_map */
 	struct mutex context_map_lock;
 
-	/* component to use next */
-	int component_idx;
 	struct vchiq_mmal_component component[VCHIQ_MMAL_MAX_COMPONENTS];
 
 	/* ordered workqueue to process all bulk operations */
@@ -1626,18 +1627,24 @@ int vchiq_mmal_component_init(struct vchiq_mmal_instance *instance,
 {
 	int ret;
 	int idx;		/* port index */
-	struct vchiq_mmal_component *component;
+	struct vchiq_mmal_component *component = NULL;
 
 	if (mutex_lock_interruptible(&instance->vchiq_mutex))
 		return -EINTR;
 
-	if (instance->component_idx == VCHIQ_MMAL_MAX_COMPONENTS) {
+	for (idx = 0; idx < VCHIQ_MMAL_MAX_COMPONENTS; idx++) {
+		if (!instance->component[idx].in_use) {
+			component = &instance->component[idx];
+			component->in_use = 1;
+			break;
+		}
+	}
+
+	if (!component) {
 		ret = -EINVAL;	/* todo is this correct error? */
 		goto unlock;
 	}
 
-	component = &instance->component[instance->component_idx];
-
 	ret = create_component(instance, component, name);
 	if (ret < 0) {
 		pr_err("%s: failed to create component %d (Not enough GPU mem?)\n",
@@ -1688,8 +1695,6 @@ int vchiq_mmal_component_init(struct vchiq_mmal_instance *instance,
 			goto release_component;
 	}
 
-	instance->component_idx++;
-
 	*component_out = component;
 
 	mutex_unlock(&instance->vchiq_mutex);
@@ -1699,6 +1704,8 @@ int vchiq_mmal_component_init(struct vchiq_mmal_instance *instance,
 release_component:
 	destroy_component(instance, component);
 unlock:
+	if (component)
+		component->in_use = 0;
 	mutex_unlock(&instance->vchiq_mutex);
 
 	return ret;
@@ -1721,6 +1728,8 @@ int vchiq_mmal_component_finalise(struct vchiq_mmal_instance *instance,
 
 	ret = destroy_component(instance, component);
 
+	component->in_use = 0;
+
 	mutex_unlock(&instance->vchiq_mutex);
 
 	return ret;

drivers/staging/vc04_services/vchiq-mmal/mmal-vchiq.h

@@ -82,6 +82,7 @@ struct vchiq_mmal_port {
 };
 
 struct vchiq_mmal_component {
+	u32 in_use:1;
 	u32 enabled:1;
 	u32 handle;  /* VideoCore handle for component */
 	u32 inputs;  /* Number of input ports */