From 8df8700bedef4d56dc1745b6d59fcba74aca38ec Mon Sep 17 00:00:00 2001
From: rabbitsaviola <delphixi@qq.com>
Date: Fri, 28 Aug 2020 21:31:30 +0800
Subject: [PATCH] Add async gpu wait interface (#1736)

Add async gpu wait interface
Closes #1708
---
 CHANGELOG.md                | 1 +
 src/lv_core/lv_refr.c       | 2 ++
 src/lv_draw/lv_draw_blend.c | 5 ++++-
 src/lv_hal/lv_hal_disp.h    | 4 ++++
 4 files changed, 11 insertions(+), 1 deletion(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 4e4b2e0f5..e4e70460a 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -10,6 +10,7 @@
 - Add `lv_font_free()` function - Frees the memory allocated by the `lv_font_load()` function
 - Add style caching to reduce acces time of properties with default value
 - Add `clean_dcache_cb` and `lv_disp_clean_dcache` to enable users to use their own cache management function
+- Add `gpu_wait_cb` to wait until the GPU is working. It allows to run CPU a wait only when the rendered data is needed.
 
 ### Bugfixes
 - Fix color bleeding on border drawing
diff --git a/src/lv_core/lv_refr.c b/src/lv_core/lv_refr.c
index 0765fba27..3ed5182db 100644
--- a/src/lv_core/lv_refr.c
+++ b/src/lv_core/lv_refr.c
@@ -741,6 +741,8 @@ static void lv_refr_vdb_flush(void)
 
     /*Flush the rendered content to the display*/
     lv_disp_t * disp = _lv_refr_get_disp_refreshing();
+    if (disp->driver.gpu_wait_cb) disp->driver.gpu_wait_cb(&disp->driver);
+
     if(disp->driver.flush_cb) disp->driver.flush_cb(&disp->driver, &vdb->area, vdb->buf_act);
 
     if(vdb->buf1 && vdb->buf2) {
diff --git a/src/lv_draw/lv_draw_blend.c b/src/lv_draw/lv_draw_blend.c
index a7d9e0d1d..f4de48e7e 100644
--- a/src/lv_draw/lv_draw_blend.c
+++ b/src/lv_draw/lv_draw_blend.c
@@ -138,7 +138,8 @@ LV_ATTRIBUTE_FAST_MEM void _lv_blend_fill(const lv_area_t * clip_area, const lv_
     const lv_area_t * disp_area = &vdb->area;
     lv_color_t * disp_buf = vdb->buf_act;
 
-
+    if (disp->driver.gpu_wait_cb) disp->driver.gpu_wait_cb(&disp->driver);
+    
     /* Get clipped fill area which is the real draw area.
      * It is always the same or inside `fill_area` */
     lv_area_t draw_area;
@@ -212,6 +213,8 @@ LV_ATTRIBUTE_FAST_MEM void _lv_blend_map(const lv_area_t * clip_area, const lv_a
     const lv_area_t * disp_area = &vdb->area;
     lv_color_t * disp_buf = vdb->buf_act;
 
+    if (disp->driver.gpu_wait_cb) disp->driver.gpu_wait_cb(&disp->driver);
+    
     /* Now `draw_area` has absolute coordinates.
      * Make it relative to `disp_area` to simplify draw to `disp_buf`*/
     draw_area.x1 -= disp_area->x1;
diff --git a/src/lv_hal/lv_hal_disp.h b/src/lv_hal/lv_hal_disp.h
index 04ea3efdf..7a1eef6b0 100644
--- a/src/lv_hal/lv_hal_disp.h
+++ b/src/lv_hal/lv_hal_disp.h
@@ -114,7 +114,11 @@ typedef struct _disp_drv_t {
     /** OPTIONAL: Called when lvgl needs any CPU cache that affects rendering to be cleaned */
     void (*clean_dcache_cb)(struct _disp_drv_t * disp_drv);
 
+    /** OPTIONAL: called to wait while the gpu is working */
+    void (*gpu_wait_cb)(struct _disp_drv_t * disp_drv);
+
 #if LV_USE_GPU
+
     /** OPTIONAL: Blend two memories using opacity (GPU only)*/
     void (*gpu_blend_cb)(struct _disp_drv_t * disp_drv, lv_color_t * dest, const lv_color_t * src, uint32_t length,
                          lv_opa_t opa);