From bf1f37f516987288288b60008232a2275ea2a3e0 Mon Sep 17 00:00:00 2001
From: Chia-I Wu <olv@google.com>
Date: Thu, 16 Feb 2023 09:18:34 -0800
Subject: [PATCH] drv: add drv_preload

It can be used to preload a backend, currently only used to preload
amdgpu.

BUG=b:269664560
TEST="grep radeonsi /proc/$(pidof zygote)/maps" on grunt

Change-Id: I30d9f701f1da3bc243a9c81326a1ba0c5e0562de
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/minigbm/+/4262034
Commit-Queue: Chia-I Wu <olv@google.com>
Reviewed-by: Yiwei Zhang <zzyiwei@chromium.org>
Tested-by: Chia-I Wu <olv@google.com>
---
 amdgpu.c   | 13 +++++++++++++
 drv.c      | 52 +++++++++++++++++++++++++++++++---------------------
 drv.h      |  2 ++
 drv_priv.h |  1 +
 4 files changed, 47 insertions(+), 21 deletions(-)

diff --git a/amdgpu.c b/amdgpu.c
index 5c891de..bcd215c 100644
--- a/amdgpu.c
+++ b/amdgpu.c
@@ -345,6 +345,18 @@ static bool is_modifier_scanout_capable(struct amdgpu_priv *priv, uint32_t forma
 	return true;
 }
 
+static void amdgpu_preload(bool load)
+{
+	static void *handle;
+
+	if (load && !handle)
+		handle = dri_dlopen(DRI_PATH);
+	else if (!load && handle) {
+		dri_dlclose(handle);
+		handle = NULL;
+	}
+}
+
 static int amdgpu_init(struct driver *drv)
 {
 	struct amdgpu_priv *priv;
@@ -788,6 +800,7 @@ static int amdgpu_bo_invalidate(struct bo *bo, struct mapping *mapping)
 
 const struct backend backend_amdgpu = {
 	.name = "amdgpu",
+	.preload = amdgpu_preload,
 	.init = amdgpu_init,
 	.close = amdgpu_close,
 	.bo_create = amdgpu_create_bo,
diff --git a/drv.c b/drv.c
index 462b763..9a6def5 100644
--- a/drv.c
+++ b/drv.c
@@ -52,6 +52,35 @@ extern const struct backend backend_virtgpu;
 extern const struct backend backend_udl;
 extern const struct backend backend_vkms;
 
+static const struct backend *drv_backend_list[] = {
+#ifdef DRV_AMDGPU
+	&backend_amdgpu,
+#endif
+#ifdef DRV_I915
+	&backend_i915,
+#endif
+#ifdef DRV_MSM
+	&backend_msm,
+#endif
+#ifdef DRV_VC4
+	&backend_vc4,
+#endif
+	&backend_evdi,	    &backend_komeda,	&backend_marvell, &backend_mediatek,
+	&backend_meson,	    &backend_nouveau,	&backend_radeon,  &backend_rockchip,
+	&backend_sun4i_drm, &backend_synaptics, &backend_udl,	  &backend_virtgpu,
+	&backend_vkms
+};
+
+void drv_preload(bool load)
+{
+	unsigned int i;
+	for (i = 0; i < ARRAY_SIZE(drv_backend_list); i++) {
+		const struct backend *b = drv_backend_list[i];
+		if (b->preload)
+			b->preload(load);
+	}
+}
+
 static const struct backend *drv_get_backend(int fd)
 {
 	drmVersionPtr drm_version;
@@ -62,27 +91,8 @@ static const struct backend *drv_get_backend(int fd)
 	if (!drm_version)
 		return NULL;
 
-	const struct backend *backend_list[] = {
-#ifdef DRV_AMDGPU
-		&backend_amdgpu,
-#endif
-#ifdef DRV_I915
-		&backend_i915,
-#endif
-#ifdef DRV_MSM
-		&backend_msm,
-#endif
-#ifdef DRV_VC4
-		&backend_vc4,
-#endif
-		&backend_evdi,	    &backend_komeda,	&backend_marvell, &backend_mediatek,
-		&backend_meson,	    &backend_nouveau,	&backend_radeon,  &backend_rockchip,
-		&backend_sun4i_drm, &backend_synaptics, &backend_udl,	  &backend_virtgpu,
-		&backend_vkms
-	};
-
-	for (i = 0; i < ARRAY_SIZE(backend_list); i++) {
-		const struct backend *b = backend_list[i];
+	for (i = 0; i < ARRAY_SIZE(drv_backend_list); i++) {
+		const struct backend *b = drv_backend_list[i];
 		if (!strcmp(drm_version->name, b->name)) {
 			drmFreeVersion(drm_version);
 			return b;
diff --git a/drv.h b/drv.h
index 7e6316c..b824fc5 100644
--- a/drv.h
+++ b/drv.h
@@ -131,6 +131,8 @@ struct mapping {
 	uint32_t refcount;
 };
 
+void drv_preload(bool load);
+
 struct driver *drv_create(int fd);
 
 void drv_destroy(struct driver *drv);
diff --git a/drv_priv.h b/drv_priv.h
index d674876..719e392 100644
--- a/drv_priv.h
+++ b/drv_priv.h
@@ -74,6 +74,7 @@ struct driver {
 
 struct backend {
 	char *name;
+	void (*preload)(bool load);
 	int (*init)(struct driver *drv);
 	void (*close)(struct driver *drv);
 	int (*bo_create)(struct bo *bo, uint32_t width, uint32_t height, uint32_t format,