From f5ff78ea0853eac8c020faf730fcf3c39ec2b090 Mon Sep 17 00:00:00 2001
From: Baptiste Wicht <baptiste.wicht@gmail.com>
Date: Sun, 12 Jan 2014 13:55:03 +0100
Subject: [PATCH] Prepare VESA Support

---
 kernel/include/vesa.hpp     | 45 +++++++++++++++++++++----------------
 kernel/src/boot/boot_16.cpp | 20 +++++++++++++++++
 2 files changed, 46 insertions(+), 19 deletions(-)

diff --git a/kernel/include/vesa.hpp b/kernel/include/vesa.hpp
index 1d269d67..ab26c574 100644
--- a/kernel/include/vesa.hpp
+++ b/kernel/include/vesa.hpp
@@ -8,31 +8,35 @@
 #ifndef VESA_H
 #define VESA_H
 
+#ifndef CODE_16
+#include "stl/types.hpp"
+#endif
+
 namespace vesa {
 
-struct vbe_info_block {
-    char[4] signature;             //"VESA"
+struct vbe_info_block_t {
+    char signature[4];             //"VESA"
     uint16_t version;              // == 0x0300 for VBE 3.0
-    uint16_t[2] oem_name_ptr;
-    uint8_t[4] capabilities;
-    uint16_t[2] video_modes_ptr;
+    uint16_t oem_name_ptr[2];
+    uint8_t capabilities[4];
+    uint16_t video_modes_ptr[2];
     uint16_t total_memory;         // as # of 64KB blocks
 
     //VBE 2.0
     uint16_t oem_software_version;
-    uint16_t[2] vendor_name_ptr;
-    uint16_t[2] product_name_ptr;
-    uint16_t[2] product_revision_ptr;
+    uint16_t vendor_name_ptr[2];
+    uint16_t product_name_ptr[2];
+    uint16_t product_revision_ptr[2];
     uint16_t vbe_af_version;
-    uint16_t[2] accelerator_video_modes_ptr;
+    uint16_t accelerator_video_modes_ptr[2];
 
-    uint8_t[216] reserved;
-    uint8_t[256] oem_scratchpad;
+    uint8_t reserved[216];
+    uint8_t oem_scratchpad[256];
 } __attribute__((packed));
 
-static_assert(sizeof(vbe_info_block) == 512, "The size of a VBE info block is 512 bytes");
+static_assert(sizeof(vbe_info_block_t) == 512, "The size of a VBE info block is 512 bytes");
 
-struct mode_info_block {
+struct mode_info_block_t {
     uint16_t mode_attributes;
     uint8_t window_a_attributes;
     uint8_t window_b_attributes;
@@ -40,7 +44,7 @@ struct mode_info_block {
     uint16_t window_size;
     uint16_t segment_window_a;
     uint16_t segment_window_b;
-    uint16_t[2] window_position_function;
+    uint16_t window_position_function[2];
     uint16_t pitch; //Bytes per scan line
 
     //OEM modes
@@ -71,8 +75,8 @@ struct mode_info_block {
 
     //VBE 2.0+
 
-    uint16_t[2] linear_video_buffer;         //LFB (Linear Framebuffer) address
-    uint16_t[2] offscreen_memory;
+    uint16_t linear_video_buffer[2];         //LFB (Linear Framebuffer) address
+    uint16_t offscreen_memory[2];
     uint16_t offscreen_memory_size;
 
     uint16_t bytes_per_scan_line;
@@ -86,11 +90,14 @@ struct mode_info_block {
     uint8_t linear_blue_mask_position;
     uint8_t linear_reserved_mask_size;
     uint8_t linear_reserved_mask_position;
-    uint16_t[2] maximum_pixel_clock;
-    uint8_t[190] reserved;
+    uint16_t maximum_pixel_clock[2];
+    uint8_t reserved_2[190];
 } __attribute__((packed));
 
-static_assert(sizeof(mode_info_block) == 256, "The size of a mode info block is 256 bytes");
+static_assert(sizeof(mode_info_block_t) == 256, "The size of a mode info block is 256 bytes");
+
+extern vbe_info_block_t vbe_info_block;
+extern bool vesa_enabled;
 
 } //end of vesa namespace
 
diff --git a/kernel/src/boot/boot_16.cpp b/kernel/src/boot/boot_16.cpp
index c96e333c..c5ce8209 100644
--- a/kernel/src/boot/boot_16.cpp
+++ b/kernel/src/boot/boot_16.cpp
@@ -34,6 +34,11 @@ typedef uint64_t size_t;
 e820::bios_e820_entry e820::bios_e820_entries[e820::MAX_E820_ENTRIES];
 int16_t e820::bios_e820_entry_count = 0;
 
+#include "vesa.hpp"
+
+vesa::vbe_info_block_t vesa::vbe_info_block;
+bool vesa::vesa_enabled = false;
+
 namespace {
 
 struct gdt_ptr {
@@ -101,6 +106,18 @@ void detect_memory(){
     e820::bios_e820_entry_count = detect_memory_e820();
 }
 
+void setup_vesa(){
+    uint16_t return_code;
+    asm volatile ("int 0x10"
+        : "=a"(return_code)
+        : "a"(0x4F00), "D"(&vesa::vbe_info_block));
+
+    if(return_code == 0x4F){
+        vesa::vesa_enabled = true;
+
+    }
+}
+
 void disable_interrupts(){
     __asm__ __volatile__ ("cli");
 }
@@ -242,6 +259,9 @@ void  __attribute__ ((noreturn)) rm_main(){
     //Analyze memory
     detect_memory();
 
+    //Enable VESA
+    setup_vesa();
+
     //Disable interrupts
     disable_interrupts();