drm_hwcomposer: Cache FB and gem in gralloc buffer

Move drm fb object creation to the importer.

In NV importer, use GRALLOC_MODULE_PERFORM_SET_IMPORTER_PRIVATE
and GRALLOC_MODULE_PERFORM_GET_IMPORTER_PRIVATE to cache the hwc_drm_bo
in the gralloc buffer.  This avoids the need to recreate fb objects
again each frame, and also greatly simplifies managing the lifetime of
the gem handles.

The drm_gralloc importer does not support caching at this point.  In an
attempt to keep it somewhat working, add hwc_import_bo_release function
that hwc calls when it's ok to rm fb.  If hwc_import_bo_release returns
true, then hwc will clean up gem handles as it did before.

We should consider doing a follow-up patch that adds fb/gem caching to
drm_gralloc importer also.  Then some of the code that is kept in this
patch for backwards compatibility can be removed.

Change-Id: I92857dcaddf8cea219ebc041e16ef76087a1b696
Reviewed-on: https://chrome-internal-review.googlesource.com/200895
Reviewed-by: Stéphane Marchesin <marcheu@google.com>
Commit-Queue: Stéphane Marchesin <marcheu@google.com>
Tested-by: Stéphane Marchesin <marcheu@google.com>
diff --git a/hwcomposer_import_nv_gralloc.cpp b/hwcomposer_import_nv_gralloc.cpp
index 4b9ad0f..f012aab 100644
--- a/hwcomposer_import_nv_gralloc.cpp
+++ b/hwcomposer_import_nv_gralloc.cpp
@@ -19,8 +19,12 @@
 #include <cutils/log.h>
 #include <hardware/gralloc.h>
 
+#include <xf86drm.h>
+#include <xf86drmMode.h>
 #include "drm_hwcomposer.h"
 
+#define ARRAY_SIZE(arr) (int)(sizeof(arr) / sizeof((arr)[0]))
+
 struct hwc_import_context {
 	const gralloc_module_t *gralloc_module;
 };
@@ -63,11 +67,105 @@
 	return 0;
 }
 
-int hwc_create_bo_from_import(int fd, hwc_import_context *ctx,
-			      buffer_handle_t handle, struct hwc_drm_bo *bo)
+struct importer_priv
 {
+	int drm_fd;
+	struct hwc_drm_bo bo;
+};
+
+static void free_priv(void *p)
+{
+	struct importer_priv *priv = (struct importer_priv *)p;
+	struct drm_gem_close gem_close;
+	int i, ret;
+
+	if (priv->bo.fb_id) {
+		ret = drmModeRmFB(priv->drm_fd, priv->bo.fb_id);
+		if (ret)
+			ALOGE("Failed to rm fb %d", ret);
+	}
+
+	memset(&gem_close, 0, sizeof(gem_close));
+	for (i = 0; i < ARRAY_SIZE(priv->bo.gem_handles); i++) {
+		if (!priv->bo.gem_handles[i])
+			continue;
+		gem_close.handle = priv->bo.gem_handles[i];
+		ret = drmIoctl(priv->drm_fd, DRM_IOCTL_GEM_CLOSE, &gem_close);
+		if (ret)
+			ALOGE("Failed to close gem handle %d", ret);
+	}
+
+	free(priv);
+}
+
+static int
+hwc_import_set_priv(hwc_import_context *ctx, buffer_handle_t handle, struct importer_priv *priv)
+{
+	int ret;
 	const gralloc_module_t *g = ctx->gralloc_module;
 
-	bo->importer_fd = -1;
-	return g->perform(g, GRALLOC_MODULE_PERFORM_DRM_IMPORT, fd, handle, bo);
+	return g->perform(g, GRALLOC_MODULE_PERFORM_SET_IMPORTER_PRIVATE, handle, free_priv, priv);
+}
+
+static struct importer_priv *
+hwc_import_get_priv(hwc_import_context *ctx, buffer_handle_t handle)
+{
+	int ret;
+	void *priv = NULL;
+	const gralloc_module_t *g = ctx->gralloc_module;
+
+	ret = g->perform(g, GRALLOC_MODULE_PERFORM_GET_IMPORTER_PRIVATE, handle, free_priv, &priv);
+	return ret ? NULL : (struct importer_priv *)priv;
+}
+
+int hwc_import_bo_create(int fd, hwc_import_context *ctx,
+			buffer_handle_t handle, struct hwc_drm_bo *bo)
+{
+	int ret = 0;
+	const gralloc_module_t *g = ctx->gralloc_module;
+
+	/* Get imported bo that is cached in gralloc buffer, or create a new one. */
+	struct importer_priv *priv = hwc_import_get_priv(ctx, handle);
+	if (!priv) {
+		priv = (struct importer_priv *)calloc(1, sizeof(*priv));
+		if (!priv)
+			return -ENOMEM;
+		priv->drm_fd = fd;
+
+		ret = g->perform(g, GRALLOC_MODULE_PERFORM_DRM_IMPORT, fd, handle, &priv->bo);
+		if (ret) {
+			ALOGE("GRALLOC_MODULE_PERFORM_DRM_IMPORT failed %d", ret);
+			free_priv(priv);
+			return ret;
+		}
+
+		ret = drmModeAddFB2(fd, priv->bo.width, priv->bo.height,
+				    priv->bo.format, priv->bo.gem_handles,
+				    priv->bo.pitches, priv->bo.offsets,
+				    &priv->bo.fb_id, 0);
+		if (ret) {
+			ALOGE("Failed to add fb %d", ret);
+			free_priv(priv);
+			return ret;
+		}
+
+		ret = hwc_import_set_priv(ctx, handle, priv);
+		if (ret) {
+			/* This will happen is persist.tegra.gpu_mapping_cache is 0/off,
+			 * or if NV gralloc runs out of "priv slots" (currently 3 per buffer,
+			 * only one of which should be used by drm_hwcomposer). */
+			ALOGE("Failed to register free callback for imported buffer %d", ret);
+			free_priv(priv);
+			return ret;
+		}
+	}
+	*bo = priv->bo;
+	return ret;
+}
+
+bool hwc_import_bo_release(int fd, hwc_import_context *ctx,
+			struct hwc_drm_bo *bo)
+{
+	/* hwc may not close the gem handles, we own them */
+	return false;
 }