[display] Refactor to avoid implicit framebuffer allocation.

target/qemu-m4/m4display.c

 /*
  * Copyright (c) 2015 Gurjant Kalsi <me@gurjantkalsi.com>
  *
  * Permission is hereby granted, free of charge, to any person obtaining
  * a copy of this software and associated documentation files
  * (the "Software"), to deal in the Software without restriction,
  * including without limitation the rights to use, copy, modify, merge,
  * publish, distribute, sublicense, and/or sell copies of the Software,
  * and to permit persons to whom the Software is furnished to do so,
  * subject to the following conditions:
@@ skipping 16 matching lines @@
 #include <trace.h>
 #include <err.h>
 
 #include <stm32f4xx.h>
 #include <stm32f4xx_spi.h>
 #include <stm32f4xx_gpio.h>
 #include <stm32f4xx_rcc.h>
 
 #include <dev/display.h>
 #include <dev/gpio.h>
-#include <lib/gfx.h>
 #include <platform/gpio.h>
+#include <assert.h>
 
 #define LOCAL_TRACE 0
 
 #define CMD_DISPLAY_NULL        0x00
 #define CMD_DISPLAY_SET_PARAM   0x01
 #define CMD_DISPLAY_OFF         0x02
 #define CMD_DISPLAY_ON          0x03
 #define CMD_DISPLAY_DRAW_SCENE  0x04
 #define CMD_DISPLAY_FRAME_BEGIN 0x05
 
@@ skipping 146 matching lines @@
         }
 
         for (int j = 0; j < M4DISPLAY_WIDTH; j++) {
             SPI_I2S_SendData(SPI6, scramble_buf[j]);
         }
     }
 
     chip_select(true);
 }
 
+status_t display_get_framebuffer(struct display_framebuffer *fb)
+{
+    DEBUG_ASSERT(fb);
+    LTRACEF("display_get_framebuffer %p\n", fb);
+
+    fb->image.pixels = (void *)framebuffer;
+    fb->image.format = IMAGE_FORMAT_RGB_2220;
+    fb->image.width = M4DISPLAY_WIDTH;
+    fb->image.height = M4DISPLAY_HEIGHT;
+    fb->image.stride = M4DISPLAY_WIDTH;
+    fb->image.rowbytes = M4DISPLAY_WIDTH;
+    fb->flush = s4lcd_flush;
+    fb->format = DISPLAY_FORMAT_UNKNOWN; //TODO
+
+    return NO_ERROR;
+}
+
 status_t display_get_info(struct display_info *info)
 {
+    DEBUG_ASSERT(info);
     LTRACEF("display_info %p\n", info);
 
-    info->framebuffer = (void *)framebuffer;
-    info->format = GFX_FORMAT_RGB_2220;
+    info->format = DISPLAY_FORMAT_UNKNOWN; //TODO
     info->width = M4DISPLAY_WIDTH;
     info->height = M4DISPLAY_HEIGHT;
-    info->stride = M4DISPLAY_WIDTH;
-    info->flush = s4lcd_flush;
 
     return NO_ERROR;
 }