feat(ppa): make the PPA burst length configurable (#9612)

Signed-off-by: Felipe Neves <felipe@lvgl.io>

Kconfig

@@ -556,6 +556,13 @@ menu "LVGL configuration"
 		default n
 		depends on LV_USE_PPA
 
+		config LV_PPA_BURST_LENGTH
+		int "PPA Burst length in bytes"
+		depends on LV_USE_PPA
+		default 128
+		help
+			PPA burst length size in bytes.
+
 		config LV_USE_DRAW_EVE
 			bool "Use EVE FT81X GPU."
 			default n

docs/src/integration/chip_vendors/espressif/tips_and_tricks.rst

@@ -107,7 +107,21 @@ To fix that behavior just add to the `sdkconfig.defaults` the following option:
 
 .. code-block:: c
 
-        CONFIG_SPIRAM_SPEED_200M=y 
+        CONFIG_SPIRAM_SPEED_200M=y
+
+Additionally it is possible to set the PPA burst length in order to increase
+the memory bandwidth of a particular channel to get speed improvement of the 
+drawing operations, using the option:
+
+.. code-block:: c
+
+        CONFIG_LV_PPA_BURST_LENGTH=128
+
+There is a downside of increasing the burst length, if another piece of code from
+ESP-IDF is using a DMA2D channel which is shared to PPA, this increase may cause 
+slow-down on that channel consumer. Also mind the burst length value supported
+are the following: 128, 64, 32, 16, and 8 bytes, other values set will result
+in a build error.
 
 
 Enabling LVGL logs on IDF project

lv_conf_template.h

@@ -395,7 +395,8 @@
 /** Draw using espressif PPA accelerator */
 #define LV_USE_PPA  0
 #if LV_USE_PPA
-    #define LV_USE_PPA_IMG 0
+    #define LV_USE_PPA_IMG      0
+    #define LV_PPA_BURST_LENGTH    128
 #endif
 
 /* Use EVE FT81X GPU. */

src/draw/espressif/ppa/lv_draw_ppa.c

@@ -48,20 +48,30 @@ void lv_draw_ppa_init(void)
     /* Register SRM client */
     cfg.oper_type = PPA_OPERATION_SRM;
     cfg.max_pending_trans_num = 1;
+#if (LV_PPA_BURST_LENGTH == 128)
     cfg.data_burst_length = PPA_DATA_BURST_LENGTH_128;
+#elif (LV_PPA_BURST_LENGTH == 64)
+    cfg.data_burst_length = PPA_DATA_BURST_LENGTH_64;
+#elif (LV_PPA_BURST_LENGTH == 32)
+    cfg.data_burst_length = PPA_DATA_BURST_LENGTH_32;
+#elif (LV_PPA_BURST_LENGTH == 16)
+    cfg.data_burst_length = PPA_DATA_BURST_LENGTH_16;
+#elif (LV_PPA_BURST_LENGTH == 8)
+    cfg.data_burst_length = PPA_DATA_BURST_LENGTH_8;
+#else
+#error "Invalid burst length selection for PPA"
+#endif
 
     res = ppa_register_client(&cfg, &draw_ppa_unit->srm_client);
     LV_ASSERT(res == ESP_OK);
 
     /* Register Fill client */
     cfg.oper_type = PPA_OPERATION_FILL;
-    cfg.data_burst_length = PPA_DATA_BURST_LENGTH_128;
     res = ppa_register_client(&cfg, &draw_ppa_unit->fill_client);
     LV_ASSERT(res == ESP_OK);
 
     /* Register Blend client */
     cfg.oper_type = PPA_OPERATION_BLEND;
-    cfg.data_burst_length = PPA_DATA_BURST_LENGTH_128;
 
     res = ppa_register_client(&cfg, &draw_ppa_unit->blend_client);
     LV_ASSERT(res == ESP_OK);

src/lv_conf_internal.h

@@ -1132,7 +1132,14 @@
         #ifdef CONFIG_LV_USE_PPA_IMG
             #define LV_USE_PPA_IMG CONFIG_LV_USE_PPA_IMG
         #else
-            #define LV_USE_PPA_IMG 0
+            #define LV_USE_PPA_IMG      0
+        #endif
+    #endif
+    #ifndef LV_PPA_BURST_LENGTH
+        #ifdef CONFIG_LV_PPA_BURST_LENGTH
+            #define LV_PPA_BURST_LENGTH CONFIG_LV_PPA_BURST_LENGTH
+        #else
+            #define LV_PPA_BURST_LENGTH    128
         #endif
     #endif
 #endif