Add a tech preview eglfs device integration for VSP2 composition

This creates a new device integration for eglfs, eglfs_kms_vsp2, that's very
similar to eglfs_kms_gbm, but includes an extra step for doing VSP2 hardware
compositing.

The main Qt content is drawn to double buffered off-screen GBM buffers which
are converted using drmPrimeHandleToFD so we get DMA buffer file descriptors
that can be used by the VSP2 blending hardware. The blending hardware writes to
double buffered DRM dumb buffers, which are flipped with drmModePageFlip.

Communicating with the VSP2 is done using the Video4Linux2 (V4L2) streaming
API. There are two steps in creating abstractions for this. First, there is the
QLinuxMedia class that consists of a Qt style wrapper for V4L2 without anything
VSP2 specific. Second, there is QVsp2BlendingDevice which hides some of the
streaming details of the VSP2 and has some level of error recovery. Both
classes include a fair bit of logging and error reporting.

The patch is written with Wayland compositors in mind, but should work for
other use cases as well.

This is just the basic support to make compositing work, additional features
may be added in subsequent patches, i.e:

- Auto-detect VSP2 (-feature-vsp2 currently needs to be explicitly enabled).
- Support for setting the alpha value of a layer.
- Support clipping layers.
- Support for scaling layers.
- Support for other output formats than RGBA32.
- Hardware cursor support.
- Support foreign layers below the main Qt layer.
- Support for memory mapped and user pointer buffer types (currently only DMA
  buffers are supported).

Change-Id: I1917d2dbdbaeded0d9c021baaa799d56afe1a9bd
Reviewed-by: Laszlo Agocs <laszlo.agocs@qt.io>

1 files changed, 242 insertions, 0 deletions

diff --git a/src/plugins/platforms/eglfs/deviceintegration/eglfs_kms_vsp2/qeglfskmsvsp2integration.cpp b/src/plugins/platforms/eglfs/deviceintegration/eglfs_kms_vsp2/qeglfskmsvsp2integration.cpp
new file mode 100644
index 0000000000..f85d6183f6
--- /dev/null
+++ b/src/plugins/platforms/eglfs/deviceintegration/eglfs_kms_vsp2/qeglfskmsvsp2integration.cpp
@@ -0,0 +1,242 @@
+/****************************************************************************
+**
+** Copyright (C) 2015 Pier Luigi Fiorini <pierluigi.fiorini@gmail.com>
+** Copyright (C) 2017 The Qt Company Ltd.
+** Copyright (C) 2016 Pelagicore AG
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the plugins of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/contact-us.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 3 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPL3 included in the
+** packaging of this file. Please review the following information to
+** ensure the GNU Lesser General Public License version 3 requirements
+** will be met: https://www.gnu.org/licenses/lgpl-3.0.html.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 2.0 or (at your option) the GNU General
+** Public license version 3 or any later version approved by the KDE Free
+** Qt Foundation. The licenses are as published by the Free Software
+** Foundation and appearing in the file LICENSE.GPL2 and LICENSE.GPL3
+** included in the packaging of this file. Please review the following
+** information to ensure the GNU General Public License requirements will
+** be met: https://www.gnu.org/licenses/gpl-2.0.html and
+** https://www.gnu.org/licenses/gpl-3.0.html.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#include "qeglfskmsvsp2integration.h"
+#include "qeglfskmsvsp2device.h"
+#include "qeglfskmsvsp2screen.h"
+#include "private/qeglfswindow_p.h"
+
+#include <QtDeviceDiscoverySupport/private/qdevicediscovery_p.h>
+#include <QtEglSupport/private/qeglconvenience_p.h>
+#include <QtCore/QLoggingCategory>
+#include <QtCore/QJsonDocument>
+#include <QtCore/QJsonObject>
+#include <QtCore/QJsonArray>
+#include <QtGui/qpa/qplatformwindow.h>
+#include <QtGui/QScreen>
+#include <QtPlatformHeaders/qeglfsfunctions.h>
+
+#include <xf86drm.h>
+#include <xf86drmMode.h>
+#include <gbm.h>
+
+QT_BEGIN_NAMESPACE
+
+QEglFSKmsVsp2Integration::QEglFSKmsVsp2Integration()
+{
+    qCDebug(qLcEglfsKmsDebug, "New DRM/KMS via Vsp2 integration created");
+}
+
+#ifndef EGL_EXT_platform_base
+typedef EGLDisplay (EGLAPIENTRYP PFNEGLGETPLATFORMDISPLAYEXTPROC) (EGLenum platform, void *native_display, const EGLint *attrib_list);
+typedef EGLSurface (EGLAPIENTRYP PFNEGLCREATEPLATFORMWINDOWSURFACEEXTPROC) (EGLDisplay dpy, EGLConfig config, void *native_window, const EGLint *attrib_list);
+#endif
+
+#ifndef EGL_PLATFORM_GBM_KHR
+#define EGL_PLATFORM_GBM_KHR 0x31D7
+#endif
+
+EGLDisplay QEglFSKmsVsp2Integration::createDisplay(EGLNativeDisplayType nativeDisplay)
+{
+    qCDebug(qLcEglfsKmsDebug, "Querying EGLDisplay");
+    EGLDisplay display;
+
+    PFNEGLGETPLATFORMDISPLAYEXTPROC getPlatformDisplay = nullptr;
+    const char *extensions = eglQueryString(EGL_NO_DISPLAY, EGL_EXTENSIONS);
+    if (extensions && (strstr(extensions, "EGL_KHR_platform_gbm") || strstr(extensions, "EGL_MESA_platform_gbm"))) {
+        getPlatformDisplay = reinterpret_cast<PFNEGLGETPLATFORMDISPLAYEXTPROC>(
+            eglGetProcAddress("eglGetPlatformDisplayEXT"));
+    }
+
+    if (getPlatformDisplay) {
+        display = getPlatformDisplay(EGL_PLATFORM_GBM_KHR, nativeDisplay, nullptr);
+    } else {
+        qCDebug(qLcEglfsKmsDebug, "No eglGetPlatformDisplay for GBM, falling back to eglGetDisplay");
+        display = eglGetDisplay(nativeDisplay);
+    }
+
+    return display;
+}
+
+EGLNativeWindowType QEglFSKmsVsp2Integration::createNativeOffscreenWindow(const QSurfaceFormat &format)
+{
+    Q_UNUSED(format);
+    Q_ASSERT(device());
+
+    gbm_surface *surface = gbm_surface_create(static_cast<QEglFSKmsVsp2Device *>(device())->gbmDevice(),
+                                              1, 1,
+                                              GBM_FORMAT_XRGB8888,
+                                              GBM_BO_USE_RENDERING);
+
+    return reinterpret_cast<EGLNativeWindowType>(surface);
+}
+
+void QEglFSKmsVsp2Integration::destroyNativeWindow(EGLNativeWindowType window)
+{
+    gbm_surface *surface = reinterpret_cast<gbm_surface *>(window);
+    //TODO call screen destroysurface instead
+    gbm_surface_destroy(surface);
+}
+
+void QEglFSKmsVsp2Integration::presentBuffer(QPlatformSurface *surface)
+{
+    QWindow *window = static_cast<QWindow *>(surface->surface());
+    auto *screen = static_cast<QEglFSKmsVsp2Screen *>(window->screen()->handle());
+    screen->flip();
+}
+
+QFunctionPointer QEglFSKmsVsp2Integration::platformFunction(const QByteArray &function) const
+{
+    if (function == QEglFSFunctions::vsp2AddLayerTypeIdentifier())
+        return QFunctionPointer(addLayerStatic);
+    if (function == QEglFSFunctions::vsp2RemoveLayerTypeIdentifier())
+        return QFunctionPointer(removeLayerStatic);
+    if (function == QEglFSFunctions::vsp2SetLayerBufferTypeIdentifier())
+        return QFunctionPointer(setLayerBufferStatic);
+    if (function == QEglFSFunctions::vsp2SetLayerPositionTypeIdentifier())
+        return QFunctionPointer(setLayerPositionStatic);
+    if (function == QEglFSFunctions::vsp2AddBlendListenerTypeIdentifier())
+        return QFunctionPointer(addBlendListenerStatic);
+
+    return nullptr;
+}
+
+QKmsDevice *QEglFSKmsVsp2Integration::createDevice()
+{
+    QString path = screenConfig()->devicePath();
+    if (!path.isEmpty()) {
+        qCDebug(qLcEglfsKmsDebug) << "VSP2: Using DRM device" << path << "specified in config file";
+    } else {
+        QDeviceDiscovery *d = QDeviceDiscovery::create(QDeviceDiscovery::Device_VideoMask);
+        const QStringList devices = d->scanConnectedDevices();
+        qCDebug(qLcEglfsKmsDebug) << "Found the following video devices:" << devices;
+        d->deleteLater();
+
+        if (Q_UNLIKELY(devices.isEmpty()))
+            qFatal("Could not find DRM device!");
+
+        path = devices.first();
+        qCDebug(qLcEglfsKmsDebug) << "Using" << path;
+    }
+
+    return new QEglFSKmsVsp2Device(screenConfig(), path);
+}
+
+int QEglFSKmsVsp2Integration::addLayerStatic(const QScreen *screen, int dmabufFd, const QSize &size, const QPoint &position, uint pixelFormat, uint bytesPerLine)
+{
+    auto vsp2Screen = static_cast<QEglFSKmsVsp2Screen *>(screen->handle());
+    return vsp2Screen->addLayer(dmabufFd, size, position, pixelFormat, bytesPerLine);
+}
+
+bool QEglFSKmsVsp2Integration::removeLayerStatic(const QScreen *screen, int id)
+{
+    auto vsp2Screen = static_cast<QEglFSKmsVsp2Screen *>(screen->handle());
+    return vsp2Screen->removeLayer(id);
+}
+
+void QEglFSKmsVsp2Integration::setLayerBufferStatic(const QScreen *screen, int id, int dmabufFd)
+{
+    auto vsp2Screen = static_cast<QEglFSKmsVsp2Screen *>(screen->handle());
+    vsp2Screen->setLayerBuffer(id, dmabufFd);
+}
+
+void QEglFSKmsVsp2Integration::setLayerPositionStatic(const QScreen *screen, int id, const QPoint &position)
+{
+    auto vsp2Screen = static_cast<QEglFSKmsVsp2Screen *>(screen->handle());
+    vsp2Screen->setLayerPosition(id, position);
+}
+
+void QEglFSKmsVsp2Integration::addBlendListenerStatic(const QScreen *screen, void(*callback)())
+{
+    auto vsp2Screen = static_cast<QEglFSKmsVsp2Screen *>(screen->handle());
+    vsp2Screen->addBlendListener(callback);
+}
+
+class QEglFSKmsVsp2Window : public QEglFSWindow
+{
+public:
+    QEglFSKmsVsp2Window(QWindow *w, const QEglFSKmsVsp2Integration *integration)
+        : QEglFSWindow(w)
+        , m_integration(integration)
+    {}
+    void resetSurface() override;
+    void invalidateSurface() override;
+    const QEglFSKmsVsp2Integration *m_integration;
+};
+
+void QEglFSKmsVsp2Window::resetSurface()
+{
+    auto *vsp2Screen = static_cast<QEglFSKmsVsp2Screen *>(screen());
+    EGLDisplay display = vsp2Screen->display();
+    QSurfaceFormat platformFormat = m_integration->surfaceFormatFor(window()->requestedFormat());
+    m_config = QEglFSDeviceIntegration::chooseConfig(display, platformFormat);
+    m_format = q_glFormatFromConfig(display, m_config, platformFormat);
+    // One fullscreen window per screen -> the native window is simply the gbm_surface the screen created.
+    m_window = reinterpret_cast<EGLNativeWindowType>(vsp2Screen->createSurface());
+
+    PFNEGLCREATEPLATFORMWINDOWSURFACEEXTPROC createPlatformWindowSurface = nullptr;
+    const char *extensions = eglQueryString(EGL_NO_DISPLAY, EGL_EXTENSIONS);
+    if (extensions && (strstr(extensions, "EGL_KHR_platform_gbm") || strstr(extensions, "EGL_MESA_platform_gbm"))) {
+        createPlatformWindowSurface = reinterpret_cast<PFNEGLCREATEPLATFORMWINDOWSURFACEEXTPROC>(
+            eglGetProcAddress("eglCreatePlatformWindowSurfaceEXT"));
+    }
+
+    if (createPlatformWindowSurface) {
+        m_surface = createPlatformWindowSurface(display, m_config, reinterpret_cast<void *>(m_window), nullptr);
+    } else {
+        qCDebug(qLcEglfsKmsDebug, "No eglCreatePlatformWindowSurface for GBM, falling back to eglCreateWindowSurface");
+        m_surface = eglCreateWindowSurface(display, m_config, m_window, nullptr);
+    }
+}
+
+void QEglFSKmsVsp2Window::invalidateSurface()
+{
+    auto *vsp2Screen = static_cast<QEglFSKmsVsp2Screen *>(screen());
+    QEglFSWindow::invalidateSurface();
+    vsp2Screen->resetSurface();
+}
+
+QEglFSWindow *QEglFSKmsVsp2Integration::createWindow(QWindow *window) const
+{
+    return new QEglFSKmsVsp2Window(window, this);
+}
+
+QT_END_NAMESPACE