Add framebuffer

fb.c

@@ -0,0 +1,66 @@
+#include "fb.h"
+#include "mbox.h"
+#include "uart.h"
+#include "utils.h"
+#include <stdint.h>
+
+#define MBOX_TAG_FBALLOC 0x40001
+#define MBOX_TAG_FBGETPITCH 0x40008
+#define MBOX_TAG_FBSETPHYS 0x48003
+#define MBOX_TAG_FBSETVIRT 0x48004
+#define MBOX_TAG_FBSETDEPTH 0x48005
+#define MBOX_TAG_FBSETPIXORD 0x48006
+#define MBOX_TAG_FBSETOFF 0x48009
+
+unsigned char *init_fb(struct fbst *fb) {
+  // sending many tags at once
+  mbox[0] = 35 * 4;
+  mbox[1] = MBOX_REQUEST;
+  mbox[2] = MBOX_TAG_FBSETPHYS; // set phy wh
+  mbox[3] = 8;
+  mbox[4] = 0;
+  mbox[5] = 1920;    // FrameBufferInfo.width
+  mbox[6] = 1080;    // FrameBufferInfo.height
+  mbox[7] = MBOX_TAG_FBSETVIRT; // set virt wh
+  mbox[8] = 8;
+  mbox[9] = 0;
+  mbox[10] = 1920;    // FrameBufferInfo.virtual_width
+  mbox[11] = 1080;    // FrameBufferInfo.virtual_height
+  mbox[12] = MBOX_TAG_FBSETOFF; // set virt offset
+  mbox[13] = 8;
+  mbox[14] = 0;
+  mbox[15] = 0;       // FrameBufferInfo.x_offset
+  mbox[16] = 0;       // FrameBufferInfo.y.offset
+  mbox[17] = MBOX_TAG_FBSETDEPTH; // set depth
+  mbox[18] = 4;
+  mbox[19] = 0;
+  mbox[20] = 32;      // FrameBufferInfo.depth
+  mbox[21] = MBOX_TAG_FBSETPIXORD; // set pixel order
+  mbox[22] = 4;
+  mbox[23] = 0;
+  mbox[24] = 1;       // RGB, not BGR preferably
+  mbox[25] = MBOX_TAG_FBALLOC; // get framebuffer, gets alignment on request
+  mbox[26] = 8;
+  mbox[27] = 0;
+  mbox[28] = 4096;    // FrameBufferInfo.pointer
+  mbox[29] = 0;       // FrameBufferInfo.size
+  mbox[30] = MBOX_TAG_FBGETPITCH; // get pitch
+  mbox[31] = 4;
+  mbox[32] = 0;
+  mbox[33] = 0; // FrameBufferInfo.pitch
+  mbox[34] = MBOX_TAG_LAST;
+
+  if (mbox_call(MBOX_CH_PROP, mbox) && mbox[20] == 32 && mbox[28] != 0) {
+    mbox[28] &= 0x3FFFFFFF; // convert GPU address to ARM address
+    fb->width = mbox[5];    // get actual physical width
+    fb->height = mbox[6];   // get actual physical height
+    fb->pitch = mbox[33];   // get number of bytes per line
+    fb->isrgb = mbox[24];   // get the actual channel order
+    fb->fbp = (void *)((unsigned long)mbox[28]);
+  } else {
+    puts("Unable to set framebuffer!\r\n");
+    return 0;
+  }
+
+  return fb->fbp;
+}

fb.h

@@ -0,0 +1,11 @@
+#pragma once
+
+struct fbst {
+    unsigned char *fbp;
+    unsigned int width;
+    unsigned int height;
+    unsigned int pitch;
+    unsigned int isrgb;
+};
+
+unsigned char *init_fb(struct fbst *fb);

hello.c

@@ -1,8 +1,15 @@
-#include "uart.h"
+#include "fb.h"
 #include "mbox.h"
+#include "uart.h"
+#include "utils.h"
 
-int kernelmain(void) {
+struct fbst fb;
+int kernelmain(void)
+{
   init_uart();
+  if (init_fb(&fb) == 0){
+    puts("Fail to init framebuffer");
+  }
   mbox[0] = 8 * 4;
   mbox[1] = MBOX_REQUEST;
   mbox[2] = MBOX_TAG_GETVCOREMEM;
@@ -23,6 +30,20 @@ int kernelmain(void) {
     puts("Error getting videocore mem\n");
   }
 
-  puts("Hello world\n");
+    unsigned char *ptr=fb.fbp;
+
+    for(int y=0; y<fb.height; y++) {
+        for(int x=0; x<fb.width; x++) {
+            if(y%60==0)
+                *((unsigned int*)ptr)=0x00FF0000;
+            else if (y%40==0)
+                *((unsigned int*)ptr)=0x0000FF00;
+            else if (y%20==0)
+                *((unsigned int*)ptr)=0x000000FF;
+            else
+                *((unsigned int*)ptr)=0x00000000;
+            ptr+=4;
+        }
+    }
   return 0;
 }

mbox.c

@@ -13,7 +13,7 @@
 //            u32: firmware revision
 //  mbox[0] = 4 * 6 // total length in byte
 //  mbox[1] = MBOX_REQUEST
-//  mbox[2] = 0x00000001
+//  mbox[2] = 0x00000001 //TAG
 //  mbox[3] = max(req_length, resp_length) -> 4
 //  mbox[5] = 0 // 0 :request, 0x80000000: response
 //  mbox[6] = MBOX_TAG_LAST