1 files changed, 79 insertions, 0 deletions
diff --git a/kernel/drivers/vbe.c b/kernel/drivers/vbe.c
new file mode 100644
index 0000000..b384936
--- /dev/null
+++ b/kernel/drivers/vbe.c
@@ -0,0 +1,79 @@
+// MIT License, Copyright (c) 2021 Marvin Borner
+
+#include <assert.h>
+#include <def.h>
+#include <drivers/cpu.h>
+#include <drivers/vbe.h>
+#include <errno.h>
+#include <io.h>
+#include <mem.h>
+#include <mm.h>
+#include <multiboot.h>
+#include <str.h>
+#include <sys.h>
+
+#define FB_SIZE (vbe->height * vbe->pitch)
+
+struct vbe_basic {
+	u8 stuff1[16];
+	u16 pitch;
+	u16 width;
+	u16 height;
+	u8 stuff2[18];
+	u8 *fb;
+	u8 stuff3[212];
+};
+
+PROTECTED static struct vbe_basic *vbe = NULL;
+
+static u32 vbe_map_buffer(struct page_dir *dir)
+{
+	assert(vbe);
+	struct memory_range r =
+		virtual_alloc(dir, memory_range_around((u32)vbe->fb, FB_SIZE), MEMORY_USER);
+	return r.base;
+}
+
+static u32 fb_owner = 0;
+static res vbe_control(u32 request, void *arg1, void *arg2, void *arg3)
+{
+	UNUSED(arg3);
+
+	switch (request) {
+	case IOCTL_FB_GET: {
+		if (!vbe)
+			return -ENOENT;
+
+		u32 size = MIN(sizeof(*vbe), (u32)arg2);
+		if (!memory_writable_range(memory_range(arg1, size)))
+			return -EFAULT;
+
+		if (fb_owner != 0 && proc_from_pid(fb_owner))
+			return -EBUSY;
+		fb_owner = proc_current()->pid;
+
+		u32 fb = vbe_map_buffer(proc_current()->page_dir);
+
+		stac();
+		memcpy(arg1, vbe, size);
+		((struct vbe_basic *)arg1)->fb = (u8 *)fb;
+		clac();
+
+		return EOK;
+	}
+	default:
+		return -EINVAL;
+	}
+}
+
+CLEAR void vbe_install(u32 data)
+{
+	vbe = (void *)data;
+
+	struct io_dev *dev = zalloc(sizeof(*dev));
+	dev->control = vbe_control;
+	io_add(IO_FRAMEBUFFER, dev);
+
+	// Set framebuffer range used to prevent unwanted writing
+	physical_set_used(memory_range_around((u32)vbe->fb, FB_SIZE));
+}