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, 326 insertions, 0 deletions

diff --git a/src/plugins/platforms/eglfs/deviceintegration/eglfs_kms_vsp2/qvsp2blendingdevice.cpp b/src/plugins/platforms/eglfs/deviceintegration/eglfs_kms_vsp2/qvsp2blendingdevice.cpp
new file mode 100644
index 0000000000..c9b9bb5b7f
--- /dev/null
+++ b/src/plugins/platforms/eglfs/deviceintegration/eglfs_kms_vsp2/qvsp2blendingdevice.cpp
@@ -0,0 +1,326 @@
+/****************************************************************************
+**
+** Copyright (C) 2017 The Qt Company Ltd.
+** 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 "qvsp2blendingdevice.h"
+#include <qeglfskmshelpers.h>
+
+#include <QDebug>
+#include <QtCore/QLoggingCategory>
+
+#include <drm_fourcc.h>
+
+QT_BEGIN_NAMESPACE
+
+Q_DECLARE_LOGGING_CATEGORY(qLcEglfsKmsDebug)
+
+//TODO: is this the right place for these conversion functions?
+static inline uint drmFormatToV4l2PixelFormat(uint drmFormat) {
+    //ARGB8888 == ABGR32 because linux media list stuff in the opposite order, but the fourcc is the same
+    Q_ASSERT(DRM_FORMAT_ARGB8888 == V4L2_PIX_FMT_ABGR32);
+    return drmFormat;
+}
+
+static uint drmFormatToMediaBusFormat(uint drmFormat)
+{
+    switch (drmFormat) {
+    case DRM_FORMAT_RGB888:
+        return MEDIA_BUS_FMT_RGB888_1X24;
+    case DRM_FORMAT_BGR888:
+        return MEDIA_BUS_FMT_BGR888_1X24;
+    case DRM_FORMAT_XRGB8888:
+    case DRM_FORMAT_XBGR8888:
+//        return MEDIA_BUS_FMT_RGB888_1X32_PADHI; // doesn't work on renesas m3, just use fallthrough to argb for now
+    case DRM_FORMAT_RGBX8888:
+    case DRM_FORMAT_BGRX8888:
+    case DRM_FORMAT_ARGB8888:
+    case DRM_FORMAT_ABGR8888:
+    case DRM_FORMAT_RGBA8888:
+    case DRM_FORMAT_BGRA8888:
+        return MEDIA_BUS_FMT_ARGB8888_1X32;
+    default:
+        qWarning() << "Unknown drm format" << q_fourccToString(drmFormat) << "defaulting to argb8888";
+        return MEDIA_BUS_FMT_ARGB8888_1X32;
+    }
+}
+
+QVsp2BlendingDevice::QVsp2BlendingDevice(const QSize &screenSize)
+    : m_mediaDevice("/dev/media0")
+    , m_screenSize(screenSize)
+{
+    QLinuxMediaDevice &md = m_mediaDevice;
+    QString deviceName = md.deviceName();
+
+    if (md.model() != QString("VSP2"))
+        qWarning() << "Unsupported media device model:" << md.model();
+
+    if (deviceName != "fe960000.vsp")
+        qWarning() << "Unknown media device name:" << deviceName;
+
+    const int numInputs = 5;
+
+    for (int i = 0; i < numInputs; ++i) {
+        Input input;
+        input.linkToBru = md.parseLink(QString("'%1 rpf.%2':1 -> '%1 bru':%2").arg(deviceName).arg(i));
+        input.inputFormatPad = md.parsePad(QString("'%1 rpf.%2':0").arg(deviceName).arg(i));
+        input.outputFormatPad = md.parsePad(QString("'%1 rpf.%2':1").arg(deviceName).arg(i));
+        input.bruInputFormatPad = md.parsePad(QString("'%1 bru':%2").arg(deviceName).arg(i));
+        input.rpfInput = new QLinuxMediaDevice::OutputSubDevice(&md, QString("%1 rpf.%2 input").arg(deviceName).arg(i));
+        m_inputs.append(input);
+    }
+
+    m_wpfOutput = new QLinuxMediaDevice::CaptureSubDevice(&md, QString("%1 wpf.0 output").arg(deviceName));
+
+    // Setup links for output
+    md.enableLink(md.parseLink(QString("'%1 bru':5 -> '%1 wpf.0':0").arg(deviceName)));
+    md.enableLink(md.parseLink(QString("'%1 wpf.0':1 -> '%1 wpf.0 output':0").arg(deviceName)));
+
+    // Output pads
+    auto bruOutputFormatPad = md.parsePad(QString("'%1 bru':5").arg(deviceName));
+    auto wpfInputFormatPad = md.parsePad(QString("'%1 wpf.0':0").arg(deviceName));
+    auto wpfOutputFormatPad = md.parsePad(QString("'%1 wpf.0':1").arg(deviceName));
+
+    m_wpfOutput->setFormat(screenSize);
+    QLinuxMediaDevice::setSubdevFormat(bruOutputFormatPad, screenSize);
+    QLinuxMediaDevice::setSubdevFormat(wpfInputFormatPad, screenSize);
+    QLinuxMediaDevice::setSubdevFormat(wpfOutputFormatPad, screenSize);
+
+    m_wpfOutput->requestBuffer();
+}
+
+bool QVsp2BlendingDevice::enableInput(int i, const QRect &bufferGeometry, uint drmFormat, uint bytesPerLine)
+{
+    qCDebug(qLcEglfsKmsDebug) << "Blend unit: Enabling input" << i;
+    if (m_inputs[i].enabled) {
+        qWarning("Vsp2: Input %d already enabled", i);
+        return false;
+    }
+
+    if (!bufferGeometry.isValid()) { //TODO: bounds checking as well?
+        qWarning() << "Vsp2: Invalid buffer geometry";
+        return false;
+    }
+
+    Input &input = m_inputs[i];
+    if (!m_mediaDevice.enableLink(input.linkToBru))
+        return false;
+
+    uint pixelFormat = drmFormatToV4l2PixelFormat(drmFormat);
+    if (!setInputFormat(i, bufferGeometry, pixelFormat, bytesPerLine)) {
+        disableInput(i);
+        return false;
+    }
+
+    input.rpfInput->requestBuffer();
+    return true;
+}
+
+int QVsp2BlendingDevice::enableInput(const QRect &bufferGeometry, uint drmFormat, uint bytesPerLine)
+{
+    for (int i = 0; i < m_inputs.size(); ++i) {
+        if (!m_inputs[i].enabled)
+            return enableInput(i, bufferGeometry, drmFormat, bytesPerLine) ? i : -1;
+    }
+    qWarning() << "Vsp2: No more inputs available in blend unit";
+    return -1;
+}
+
+bool QVsp2BlendingDevice::disableInput(int i)
+{
+    qCDebug(qLcEglfsKmsDebug) << "Vsp2: disabling input" << i;
+    if (!m_inputs[i].enabled) {
+        qWarning("Vsp2: Input %d already disabled", i);
+        return false;
+    }
+    m_mediaDevice.disableLink(m_inputs[i].linkToBru);
+    m_inputs[i].rpfInput->clearBuffers();
+    m_inputs[i].enabled = false;
+    return true;
+}
+
+bool QVsp2BlendingDevice::setInputBuffer(int index, int dmabufFd)
+{
+    Input &input = m_inputs[index];
+
+    if (!input.enabled) {
+        qWarning() << "Vsp2: Can't queue on disabled input" << index;
+        return false;
+    }
+
+    // Don't queue the buffer yet, store it here and wait until blending
+    if (input.dmabuf.fd != dmabufFd) {
+        m_dirty = true;
+        input.dmabuf.fd = dmabufFd;
+    }
+    return true;
+}
+
+bool QVsp2BlendingDevice::setInputPosition(int index, const QPoint &position)
+{
+    Input &input = m_inputs[index];
+
+    if (input.geometry.topLeft() == position)
+        return true;
+
+    m_dirty = true;
+    input.geometry.moveTopLeft(position);
+    return QLinuxMediaDevice::setSubdevCompose(input.bruInputFormatPad, input.geometry);
+}
+
+bool QVsp2BlendingDevice::blend(int outputDmabufFd)
+{
+    if (!m_dirty)
+        qWarning("Blending without being dirty, should not be necessary");
+
+    if (!m_inputs[0].enabled) {
+        qWarning("Vsp2: Can't blend with layer 0 disabled");
+        return false;
+    }
+
+    // Queue dma input buffers
+    for (int i=0; i < m_inputs.size(); ++i) {
+        auto &input = m_inputs[i];
+        if (input.enabled) {
+            if (!input.rpfInput->queueBuffer(input.dmabuf.fd, input.dmabuf.bytesUsed, input.dmabuf.length)) {
+                qWarning() << "Vsp2: Failed to queue buffer for input" << i
+                           << "with dmabuf" << input.dmabuf.fd
+                           << "and size" << input.geometry.size();
+
+                if (!disableInput(i))
+                    qWarning() << "Vsp2: Failed to disable input" << i;
+            }
+        }
+    }
+
+    if (!m_wpfOutput->queueBuffer(outputDmabufFd, m_screenSize)) {
+        qWarning() << "Vsp2: Failed to queue blending output buffer" << outputDmabufFd << m_screenSize;
+        return false;
+    }
+
+    if (!streamOn()) {
+        qWarning() << "Vsp2: Failed to start streaming";
+        return false;
+    }
+
+    if (!m_wpfOutput->dequeueBuffer()) {
+        qWarning() << "Vsp2: Failed to dequeue blending output buffer";
+        return false;
+    }
+
+    if (!streamOff()) {
+        qWarning() << "Vsp2: Failed to stop streaming";
+        return false;
+    }
+
+    m_dirty = false;
+    return true;
+}
+
+int QVsp2BlendingDevice::numInputs() const
+{
+    return m_inputs.size();
+}
+
+bool QVsp2BlendingDevice::streamOn()
+{
+    for (auto &input : m_inputs) {
+        if (input.enabled) {
+            if (!input.rpfInput->streamOn()) {
+                //TODO: perhaps it's better to try to continue with the other inputs?
+                return false;
+            }
+        }
+    }
+
+    return m_wpfOutput->streamOn();
+}
+
+bool QVsp2BlendingDevice::streamOff()
+{
+    if (!m_wpfOutput->streamOff()) {
+        //TODO: perhaps it's better to try to continue with the other inputs?
+        return false;
+    }
+
+    for (auto &input : m_inputs) {
+        if (input.enabled) {
+            if (!input.rpfInput->streamOff())
+                return false;
+        }
+    }
+
+    return true;
+}
+
+bool QVsp2BlendingDevice::setInputFormat(int i, const QRect &bufferGeometry, uint pixelFormat, uint bytesPerLine)
+{
+    Input &input = m_inputs[i];
+
+    Q_ASSERT(bufferGeometry.isValid());
+
+    const uint bpp = 4; //TODO: don't hardcode bpp, get it from pixelFormat?
+    input.enabled = true;
+    input.geometry = bufferGeometry;
+    input.dmabuf.bytesUsed = bpp * static_cast<uint>(bufferGeometry.width()) * static_cast<uint>(bufferGeometry.height());
+    input.dmabuf.length = static_cast<uint>(bufferGeometry.height()) * bytesPerLine;
+
+    const QSize size = bufferGeometry.size();
+
+    if (!input.rpfInput->setFormat(size, pixelFormat, bytesPerLine)) // rpf.x input
+        return false;
+
+    const uint mediaBusFormat = drmFormatToMediaBusFormat(pixelFormat);
+    if (!QLinuxMediaDevice::setSubdevFormat(input.inputFormatPad, size, mediaBusFormat)) // rpf.x:0
+        return false;
+
+    if (!QLinuxMediaDevice::setSubdevFormat(input.outputFormatPad, size, mediaBusFormat)) // rpf.x:1
+        return false;
+
+    if (!QLinuxMediaDevice::setSubdevFormat(input.bruInputFormatPad, size, mediaBusFormat)) // bru:x
+        return false;
+
+    if (!QLinuxMediaDevice::setSubdevCrop(input.inputFormatPad, QRect(QPoint(0, 0), size)))
+        return false;
+
+    if (!QLinuxMediaDevice::setSubdevCompose(input.bruInputFormatPad, bufferGeometry))
+        return false;
+
+    return true;
+}
+
+QT_END_NAMESPACE