Kernel: Add Framebuffer class for Raspberry Pi

It initializes framebuffer and exposes access to its properties.

Kernel/Prekernel/Arch/aarch64/Framebuffer.cpp

@@ -0,0 +1,114 @@
+/*
+ * Copyright (c) 2021, Marcin Undak <mcinek@gmail.com>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#include <Kernel/Prekernel/Arch/aarch64/Framebuffer.h>
+#include <Kernel/Prekernel/Arch/aarch64/FramebufferMailboxMessages.h>
+#include <Kernel/Prekernel/Arch/aarch64/Utils.h>
+
+namespace Prekernel {
+
+Framebuffer::Framebuffer()
+{
+    // FIXME: query HDMI for best mode
+    // https://github.com/raspberrypi/userland/blob/master/host_applications/linux/apps/tvservice/tvservice.c
+    m_width = 1280;
+    m_height = 720;
+    m_depth = 32;
+    m_initialized = false;
+
+    struct __attribute__((aligned(16))) {
+        Mailbox::MessageHeader header;
+        FramebufferSetPhysicalSizeMboxMessage set_physical_size;
+        FramebufferSetVirtualSizeMboxMessage set_virtual_size;
+        FramebufferSetVirtualOffsetMboxMessage set_virtual_offset;
+        FramebufferSetDepthMboxMessage set_depth;
+        FramebufferSetPixelOrderMboxMessage set_pixel_order;
+        FramebufferAllocateBufferMboxMessage allocate_buffer;
+        FramebufferGetPithMboxMessage get_pitch;
+        Mailbox::MessageTail tail;
+    } message_queue;
+
+    message_queue.header.set_queue_size(sizeof(message_queue));
+    message_queue.set_physical_size.width = m_width;
+    message_queue.set_physical_size.height = m_height;
+    message_queue.set_virtual_size.width = m_width;
+    message_queue.set_virtual_size.height = m_height;
+
+    // FIXME! those next 2 lines crash...
+    // message_queue.set_virtual_offset.x = 0;
+    // message_queue.set_virtual_offset.y = 0;
+
+    message_queue.set_depth.depth_bits = 32;
+    message_queue.set_pixel_order.pixel_order = FramebufferSetPixelOrderMboxMessage::PixelOrder::RGB;
+    message_queue.allocate_buffer.alignment = 4096;
+
+    if (!Mailbox::the().send_queue(&message_queue, sizeof(message_queue))) {
+        warnln("Framebuffer(): Mailbox send failed.");
+        return;
+    }
+
+    // Now message queue contains responses. Process them.
+
+    if (message_queue.set_physical_size.width != m_width || message_queue.set_physical_size.height != m_height) {
+        warnln("Framebuffer(): Setting physical dimension failed.");
+        return;
+    }
+
+    if (message_queue.set_virtual_size.width != m_width || message_queue.set_virtual_size.height != m_height) {
+        warnln("Framebuffer(): Setting virtual dimension failed.");
+        return;
+    }
+
+    if (message_queue.set_virtual_offset.x != 0 || message_queue.set_virtual_offset.y != 0) {
+        warnln("Framebuffer(): Setting virtual offset failed.");
+        return;
+    }
+
+    if (message_queue.set_depth.depth_bits != m_depth) {
+        warnln("Framebuffer(): Setting depth failed.");
+        return;
+    }
+
+    if (message_queue.allocate_buffer.size == 0 || message_queue.allocate_buffer.address == 0) {
+        warnln("Framebuffer(): Allocating buffer failed.");
+        return;
+    }
+
+    if (message_queue.get_pitch.pitch == 0) {
+        warnln("Framebuffer(): Retrieving pitch failed.");
+        return;
+    }
+
+    // Convert GPU address space to RAM
+    // GPU maps memory from 0x80000000 instead of 0x00000000
+    m_gpu_buffer = reinterpret_cast<u8*>(message_queue.allocate_buffer.address & 0x3FFFFFFF);
+
+    m_buffer_size = message_queue.allocate_buffer.size;
+    m_pitch = message_queue.get_pitch.pitch;
+
+    switch (message_queue.set_pixel_order.pixel_order) {
+    case FramebufferSetPixelOrderMboxMessage::PixelOrder::RGB:
+        m_pixel_order = PixelOrder::RGB;
+        break;
+    case FramebufferSetPixelOrderMboxMessage::PixelOrder::BGR:
+        m_pixel_order = PixelOrder::BGR;
+        break;
+    default:
+        warnln("Framebuffer(): Unsupported pixel order reported by GPU.");
+        m_pixel_order = PixelOrder::RGB;
+        break;
+    }
+
+    dbgln("Initialized framebuffer: 1280 x 720 @ 32 bits");
+    m_initialized = true;
+}
+
+Framebuffer& Framebuffer::the()
+{
+    static Framebuffer instance;
+    return instance;
+}
+}

Kernel/Prekernel/Arch/aarch64/Framebuffer.h

@@ -0,0 +1,43 @@
+/*
+ * Copyright (c) 2021, Marcin Undak <mcinek@gmail.com>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#pragma once
+
+#include <AK/Types.h>
+
+namespace Prekernel {
+
+class Framebuffer {
+public:
+    enum class PixelOrder {
+        RGB,
+        BGR,
+    };
+
+    static Framebuffer& the();
+
+    bool initialized() const { return m_initialized; }
+    u16 width() const { return m_width; }
+    u16 height() const { return m_height; }
+    u8 depth() const { return m_depth; }
+    u8* gpu_buffer() const { return m_gpu_buffer; }
+    u32 buffer_size() const { return m_buffer_size; }
+    u32 pitch() const { return m_pitch; }
+    PixelOrder pixel_order() { return m_pixel_order; }
+
+private:
+    u16 m_width;
+    u16 m_height;
+    u8 m_depth;
+    u8* m_gpu_buffer;
+    u32 m_buffer_size;
+    u32 m_pitch;
+    bool m_initialized;
+    PixelOrder m_pixel_order;
+
+    Framebuffer();
+};
+}

Kernel/Prekernel/Arch/aarch64/FramebufferMailboxMessages.h

@@ -22,6 +22,7 @@ public:
         height = 0;
     }
 };
+static_assert(sizeof(FramebufferSetPhysicalSizeMboxMessage) == 20);
 
 class FramebufferSetVirtualSizeMboxMessage : public Mailbox::Message {
 public:
@@ -35,6 +36,7 @@ public:
         height = 0;
     }
 };
+static_assert(sizeof(FramebufferSetVirtualSizeMboxMessage) == 20);
 
 class FramebufferSetVirtualOffsetMboxMessage : public Mailbox::Message {
 public:
@@ -48,6 +50,7 @@ public:
         y = 0;
     }
 };
+static_assert(sizeof(FramebufferSetVirtualOffsetMboxMessage) == 20);
 
 class FramebufferSetDepthMboxMessage : public Mailbox::Message {
 public:
@@ -59,6 +62,7 @@ public:
         depth_bits = 0;
     }
 };
+static_assert(sizeof(FramebufferSetDepthMboxMessage) == 16);
 
 class FramebufferSetPixelOrderMboxMessage : public Mailbox::Message {
 public:
@@ -75,6 +79,7 @@ public:
         pixel_order = PixelOrder::BGR;
     }
 };
+static_assert(sizeof(FramebufferSetPixelOrderMboxMessage) == 16);
 
 class FramebufferAllocateBufferMboxMessage : public Mailbox::Message {
 public:
@@ -91,6 +96,7 @@ public:
         size = 0;
     }
 };
+static_assert(sizeof(FramebufferAllocateBufferMboxMessage) == 20);
 
 class FramebufferGetPithMboxMessage : public Mailbox::Message {
 public:
@@ -102,4 +108,6 @@ public:
         pitch = 0;
     }
 };
+static_assert(sizeof(FramebufferGetPithMboxMessage) == 16);
+
 }

Kernel/Prekernel/CMakeLists.txt

@@ -5,14 +5,15 @@ set(SOURCES
 if ("${SERENITY_ARCH}" STREQUAL "aarch64")
     set(SOURCES
         ${SOURCES}
+        Arch/aarch64/Aarch64_asm_utils.S
         Arch/aarch64/GPIO.cpp
+        Arch/aarch64/Framebuffer.cpp
         Arch/aarch64/Mailbox.cpp
         Arch/aarch64/MainIdRegister.cpp
         Arch/aarch64/MMIO.cpp
         Arch/aarch64/Timer.cpp
         Arch/aarch64/UART.cpp
         Arch/aarch64/Utils.cpp
-        Arch/aarch64/Aarch64_asm_utils.S
         Arch/aarch64/boot.S
         Arch/aarch64/init.cpp
     )