From a38f95a7b8f24d8b98575614df48bd5594823e1a Mon Sep 17 00:00:00 2001
From: Josh Holtrop <jholtrop@gmail.com>
Date: Mon, 14 Mar 2022 22:26:55 -0400
Subject: [PATCH] Set graphics mode

---
 Rsconscript               |  4 +--
 src/hel/hel.d             | 67 ++++++++++++++++++++++++++++++++-------
 src/hel/output.d          |  2 +-
 src/kernel/hos/bootinfo.d | 19 +++++++++++
 4 files changed, 77 insertions(+), 15 deletions(-)
 create mode 100644 src/kernel/hos/bootinfo.d

diff --git a/Rsconscript b/Rsconscript
index 78b76b2..a24adbf 100644
--- a/Rsconscript
+++ b/Rsconscript
@@ -73,10 +73,10 @@ end
 
 hel_env = env "hel", use: %w[ldc2 x86_64-w64-mingw32-gcc] do |env|
   env.add_builder(Image)
-  env["sources"] = glob("src/hel/**/*.d")
+  env["sources"] = glob("src/hel/**/*.d", "src/kernel/hos/bootinfo.d")
   env["sources"] += glob("uefi-d/source/**/*.d")
   env["DFLAGS"] += %w[-mtriple=x86_64-unknown-windows-coff --betterC -release -O3 --wi]
-  env["D_IMPORT_PATH"] += %w[src/hel uefi-d/source]
+  env["D_IMPORT_PATH"] += %w[src/hel src/kernel uefi-d/source]
   env["LD"] = "x86_64-w64-mingw32-gcc"
   env["LDFLAGS"] += %w[-nostdlib -Wl,-dll -shared -Wl,--subsystem,10 -e efi_main -Wl,-Map,${_TARGET}.map]
   env["LDCMD"] = %w[${LD} -o ${_TARGET} ${LDFLAGS} ${_SOURCES} ${LIBDIRPREFIX}${LIBPATH} ${LIBLINKPREFIX}${LIBS}]
diff --git a/src/hel/hel.d b/src/hel/hel.d
index e24e1ad..467d1a7 100644
--- a/src/hel/hel.d
+++ b/src/hel/hel.d
@@ -1,28 +1,23 @@
 import uefi;
 import output;
 import heap;
+import hos.bootinfo;
 
-__gshared EFI_SYSTEM_TABLE * g_st;
+__gshared EFI_SYSTEM_TABLE * st;
+__gshared BootInfo * bootinfo;
 
 private void wait_key()
 {
     writeln("Press any key...");
-    g_st.ConIn.Reset(g_st.ConIn, FALSE);
+    st.ConIn.Reset(st.ConIn, FALSE);
     EFI_INPUT_KEY key;
-    while (g_st.ConIn.ReadKeyStroke(g_st.ConIn, &key) == EFI_NOT_READY)
+    while (st.ConIn.ReadKeyStroke(st.ConIn, &key) == EFI_NOT_READY)
     {
     }
 }
 
-extern (C) EFI_STATUS efi_main(EFI_HANDLE image_handle, EFI_SYSTEM_TABLE * st)
+private bool set_graphics_mode()
 {
-    g_st = st;
-
-    st.ConOut.ClearScreen(st.ConOut);
-
-    writeln("HOS EFI loader");
-    writeln("Firmware vendor: '%S', version: 0x%x", st.FirmwareVendor, st.FirmwareVendor);
-
     UINTN buffer_size = heap_free();
     EFI_GUID gop_guid = EFI_GRAPHICS_OUTPUT_PROTOCOL_GUID;
     EFI_HANDLE * handles = cast(EFI_HANDLE *)heap_base();
@@ -31,10 +26,58 @@ extern (C) EFI_STATUS efi_main(EFI_HANDLE image_handle, EFI_SYSTEM_TABLE * st)
     if (status != EFI_SUCCESS)
     {
         writeln("LocateHandle: error %u", status);
+        return false;
+    }
+    EFI_HANDLE gop_handle = handles[0];
+    EFI_HANDLE gop_interface;
+    status = st.BootServices.HandleProtocol(gop_handle,
+            &gop_guid, &gop_interface);
+    if (status != EFI_SUCCESS)
+    {
+        writeln("HandleProtocol: error %u", status);
+        return false;
+    }
+    if (gop_interface == null)
+    {
+        writeln("null interface from HandleProtocol");
+        return false;
+    }
+    EFI_GRAPHICS_OUTPUT_PROTOCOL * gop = cast(EFI_GRAPHICS_OUTPUT_PROTOCOL *)gop_interface;
+    UINTN info_size;
+    EFI_GRAPHICS_OUTPUT_MODE_INFORMATION * info;
+    uint best_width;
+    uint best_mode_number;
+    for (uint mode_number = 0u;
+         (status = gop.QueryMode(gop, mode_number, &info_size, &info)) == EFI_SUCCESS;
+         mode_number++)
+    {
+        if (info.HorizontalResolution > best_width)
+        {
+            best_width = info.HorizontalResolution;
+            best_mode_number = mode_number;
+        }
+        st.BootServices.FreePool(info);
+    }
+    gop.SetMode(gop, best_mode_number);
+    return true;
+}
+
+extern (C) EFI_STATUS efi_main(EFI_HANDLE image_handle, EFI_SYSTEM_TABLE * st)
+{
+    .st = st;
+
+    st.ConOut.ClearScreen(st.ConOut);
+
+    writeln("HOS EFI loader");
+    writeln("Firmware vendor: '%S', version: 0x%x", st.FirmwareVendor, st.FirmwareVendor);
+
+    bootinfo = cast(BootInfo *)heap_consume(BootInfo.sizeof);
+
+    if (!set_graphics_mode())
+    {
         wait_key();
         return EFI_SUCCESS;
     }
-    EFI_HANDLE gop_handle = handles[0];
 
     wait_key();
 
diff --git a/src/hel/output.d b/src/hel/output.d
index 96506f4..537c761 100644
--- a/src/hel/output.d
+++ b/src/hel/output.d
@@ -101,7 +101,7 @@ void write(string s, va_list args)
         }
     }
     s16[i++] = 0u;
-    g_st.ConOut.OutputString(g_st.ConOut, &s16[0]);
+    st.ConOut.OutputString(st.ConOut, &s16[0]);
 }
 
 extern (C) void write(string s, ...)
diff --git a/src/kernel/hos/bootinfo.d b/src/kernel/hos/bootinfo.d
new file mode 100644
index 0000000..68cda2d
--- /dev/null
+++ b/src/kernel/hos/bootinfo.d
@@ -0,0 +1,19 @@
+struct BootInfo
+{
+    struct MemoryRegion
+    {
+        void * base;
+        size_t size;
+    }
+    struct Framebuffer
+    {
+        uint * buffer;
+        uint width;
+        uint height;
+        uint stride;
+        uint format;
+    }
+    Framebuffer fb;
+    MemoryRegion * memory_map;
+    uint memory_map_size;
+}