1 files changed, 91 insertions, 0 deletions
diff --git a/src/graphics/lfb.c b/src/graphics/lfb.c
new file mode 100644
index 0000000..682f719
--- /dev/null
+++ b/src/graphics/lfb.c
@@ -0,0 +1,91 @@
+#include "../drivers/uart.h"
+#include "../graphics/mbox.h"
+#include "../graphics/homer.h"
+
+unsigned int width, height, pitch, isrgb;   /* dimensions and channel order */
+unsigned char *lfb;                         /* raw frame buffer address */
+
+/**
+ * Set screen resolution to 1024x768
+ */
+void lfb_init()
+{
+    mbox[0] = 35*4;
+    mbox[1] = MBOX_REQUEST;
+
+    mbox[2] = 0x48003;  //set phy wh
+    mbox[3] = 8;
+    mbox[4] = 8;
+    mbox[5] = 1024;         //FrameBufferInfo.width
+    mbox[6] = 768;          //FrameBufferInfo.height
+
+    mbox[7] = 0x48004;  //set virt wh
+    mbox[8] = 8;
+    mbox[9] = 8;
+    mbox[10] = 1024;        //FrameBufferInfo.virtual_width
+    mbox[11] = 768;         //FrameBufferInfo.virtual_height
+
+    mbox[12] = 0x48009; //set virt offset
+    mbox[13] = 8;
+    mbox[14] = 8;
+    mbox[15] = 0;           //FrameBufferInfo.x_offset
+    mbox[16] = 0;           //FrameBufferInfo.y.offset
+
+    mbox[17] = 0x48005; //set depth
+    mbox[18] = 4;
+    mbox[19] = 4;
+    mbox[20] = 32;          //FrameBufferInfo.depth
+
+    mbox[21] = 0x48006; //set pixel order
+    mbox[22] = 4;
+    mbox[23] = 4;
+    mbox[24] = 1;           //RGB, not BGR preferably
+
+    mbox[25] = 0x40001; //get framebuffer, gets alignment on request
+    mbox[26] = 8;
+    mbox[27] = 8;
+    mbox[28] = 4096;        //FrameBufferInfo.pointer
+    mbox[29] = 0;           //FrameBufferInfo.size
+
+    mbox[30] = 0x40008; //get pitch
+    mbox[31] = 4;
+    mbox[32] = 4;
+    mbox[33] = 0;           //FrameBufferInfo.pitch
+
+    mbox[34] = MBOX_TAG_LAST;
+
+    //this might not return exactly what we asked for, could be
+    //the closest supported resolution instead
+    if(mbox_call(MBOX_CH_PROP) && mbox[20]==32 && mbox[28]!=0) {
+        mbox[28]&=0x3FFFFFFF;   //convert GPU address to ARM address
+        width=mbox[5];          //get actual physical width
+        height=mbox[6];         //get actual physical height
+        pitch=mbox[33];         //get number of bytes per line
+        isrgb=mbox[24];         //get the actual channel order
+        lfb=(void*)((unsigned long)mbox[28]);
+    } else {
+        uart_string("Unable to set screen resolution to 1024x768x32\n");
+    }
+}
+
+/**
+ * Show a picture
+ */
+void lfb_showpicture()
+{
+    unsigned int x,y;
+    unsigned char *ptr=lfb;
+    char *data=homer_data, pixel[4];
+
+    ptr += (height-homer_height)/2*pitch + (width-homer_width)*2;
+    for(y=0;y<homer_height;y++) {
+        for(x=0;x<homer_width;x++) {
+            HEADER_PIXEL(data, pixel);
+            // the image is in RGB. So if we have an RGB framebuffer, we can copy the pixels
+            // directly, but for BGR we must swap R (pixel[0]) and B (pixel[2]) channels.
+            *((unsigned int*)ptr)=isrgb ? *((unsigned int *)&pixel) : (unsigned int)(pixel[0]<<16 | pixel[1]<<8 | pixel[2]);
+            ptr+=4;
+        }
+        ptr+=pitch-homer_width*4;
+    }
+}