File indexing completed on 2024-05-12 05:31:21

 /*
     SPDX-FileCopyrightText: 2023 Vlad Zahorodnii <vlad.zahorodnii@kde.org>
 
     SPDX-License-Identifier: GPL-2.0-or-later
 */
 
 #include "core/gbmgraphicsbufferallocator.h"
 
 #include <config-kwin.h>
 
 #include "core/graphicsbuffer.h"
 #include "utils/common.h"
 
 #include <drm_fourcc.h>
 #include <fcntl.h>
 #include <gbm.h>
 #include <sys/mman.h>
 #include <xf86drm.h>
 
 namespace KWin
 {
 
 static inline std::optional<DmaBufAttributes> dmaBufAttributesForBo(gbm_bo *bo)
 {
     DmaBufAttributes attributes;
     attributes.planeCount = gbm_bo_get_plane_count(bo);
     attributes.width = gbm_bo_get_width(bo);
     attributes.height = gbm_bo_get_height(bo);
     attributes.format = gbm_bo_get_format(bo);
     attributes.modifier = gbm_bo_get_modifier(bo);
 
 #if HAVE_GBM_BO_GET_FD_FOR_PLANE
     for (int i = 0; i < attributes.planeCount; ++i) {
         attributes.fd[i] = FileDescriptor{gbm_bo_get_fd_for_plane(bo, i)};
         if (!attributes.fd[i].isValid()) {
             qWarning() << "gbm_bo_get_fd_for_plane() failed:" << strerror(errno);
             return std::nullopt;
         }
         attributes.offset[i] = gbm_bo_get_offset(bo, i);
         attributes.pitch[i] = gbm_bo_get_stride_for_plane(bo, i);
     }
 #else
     if (attributes.planeCount > 1) {
         return attributes;
     }
 
     attributes.fd[0] = FileDescriptor{gbm_bo_get_fd(bo)};
     if (!attributes.fd[0].isValid()) {
         qWarning() << "gbm_bo_get_fd() failed:" << strerror(errno);
         return std::nullopt;
     }
     attributes.offset[0] = gbm_bo_get_offset(bo, 0);
     attributes.pitch[0] = gbm_bo_get_stride_for_plane(bo, 0);
 #endif
 
     return attributes;
 }
 
 class GbmGraphicsBuffer : public GraphicsBuffer
 {
     Q_OBJECT
 
 public:
     GbmGraphicsBuffer(DmaBufAttributes attributes, gbm_bo *handle);
     ~GbmGraphicsBuffer() override;
 
     Map map(MapFlags flags) override;
     void unmap() override;
 
     QSize size() const override;
     bool hasAlphaChannel() const override;
     const DmaBufAttributes *dmabufAttributes() const override;
 
 private:
     gbm_bo *m_bo;
     void *m_mapPtr = nullptr;
     void *m_mapData = nullptr;
     // the stride of the buffer mapping can be different from the stride of the buffer itself
     uint32_t m_mapStride = 0;
     DmaBufAttributes m_dmabufAttributes;
     QSize m_size;
     bool m_hasAlphaChannel;
 };
 
 class DumbGraphicsBuffer : public GraphicsBuffer
 {
     Q_OBJECT
 
 public:
     DumbGraphicsBuffer(int drmFd, uint32_t handle, DmaBufAttributes attributes);
     ~DumbGraphicsBuffer() override;
 
     Map map(MapFlags flags) override;
     void unmap() override;
 
     QSize size() const override;
     bool hasAlphaChannel() const override;
     const DmaBufAttributes *dmabufAttributes() const override;
 
 private:
     int m_drmFd;
     uint32_t m_handle;
     void *m_data = nullptr;
     size_t m_size = 0;
     DmaBufAttributes m_dmabufAttributes;
     bool m_hasAlphaChannel;
 };
 
 GbmGraphicsBufferAllocator::GbmGraphicsBufferAllocator(gbm_device *device)
     : m_gbmDevice(device)
 {
 }
 
 GbmGraphicsBufferAllocator::~GbmGraphicsBufferAllocator()
 {
 }
 
 static GraphicsBuffer *allocateDumb(gbm_device *device, const GraphicsBufferOptions &options)
 {
     if (!options.modifiers.isEmpty()) {
         return nullptr;
     }
 
     drm_mode_create_dumb createArgs{
         .height = uint32_t(options.size.height()),
         .width = uint32_t(options.size.width()),
         .bpp = 32,
     };
     if (drmIoctl(gbm_device_get_fd(device), DRM_IOCTL_MODE_CREATE_DUMB, &createArgs) != 0) {
         qCWarning(KWIN_CORE) << "DRM_IOCTL_MODE_CREATE_DUMB failed:" << strerror(errno);
         return nullptr;
     }
 
     int primeFd;
     if (drmPrimeHandleToFD(gbm_device_get_fd(device), createArgs.handle, DRM_CLOEXEC, &primeFd) != 0) {
         qCWarning(KWIN_CORE) << "drmPrimeHandleToFD() failed:" << strerror(errno);
         drm_mode_destroy_dumb destroyArgs{
             .handle = createArgs.handle,
         };
         drmIoctl(gbm_device_get_fd(device), DRM_IOCTL_MODE_DESTROY_DUMB, &destroyArgs);
         return nullptr;
     }
 
     return new DumbGraphicsBuffer(gbm_device_get_fd(device), createArgs.handle, DmaBufAttributes{
         .planeCount = 1,
         .width = options.size.width(),
         .height = options.size.height(),
         .format = options.format,
         .modifier = DRM_FORMAT_MOD_LINEAR,
         .fd = {FileDescriptor(primeFd), FileDescriptor{}, FileDescriptor{}, FileDescriptor{}},
         .offset = {0, 0, 0, 0},
         .pitch = {createArgs.pitch, 0, 0, 0},
     });
 }
 
 static GraphicsBuffer *allocateDmaBuf(gbm_device *device, const GraphicsBufferOptions &options)
 {
     if (!options.modifiers.isEmpty() && !(options.modifiers.size() == 1 && options.modifiers.first() == DRM_FORMAT_MOD_INVALID)) {
         gbm_bo *bo = gbm_bo_create_with_modifiers(device,
                                                   options.size.width(),
                                                   options.size.height(),
                                                   options.format,
                                                   options.modifiers.constData(),
                                                   options.modifiers.size());
         if (bo) {
             std::optional<DmaBufAttributes> attributes = dmaBufAttributesForBo(bo);
             if (!attributes.has_value()) {
                 gbm_bo_destroy(bo);
                 return nullptr;
             }
             return new GbmGraphicsBuffer(std::move(attributes.value()), bo);
         }
     }
 
     uint32_t flags = GBM_BO_USE_SCANOUT | GBM_BO_USE_RENDERING;
     if (options.modifiers.size() == 1 && options.modifiers.first() == DRM_FORMAT_MOD_LINEAR) {
         flags |= GBM_BO_USE_LINEAR;
     } else if (!options.modifiers.isEmpty() && !options.modifiers.contains(DRM_FORMAT_MOD_INVALID)) {
         return nullptr;
     }
 
     gbm_bo *bo = gbm_bo_create(device,
                                options.size.width(),
                                options.size.height(),
                                options.format,
                                flags);
     if (bo) {
         std::optional<DmaBufAttributes> attributes = dmaBufAttributesForBo(bo);
         if (!attributes.has_value()) {
             gbm_bo_destroy(bo);
             return nullptr;
         }
         if (flags & GBM_BO_USE_LINEAR) {
             attributes->modifier = DRM_FORMAT_MOD_LINEAR;
         } else {
             attributes->modifier = DRM_FORMAT_MOD_INVALID;
         }
         return new GbmGraphicsBuffer(std::move(attributes.value()), bo);
     }
 
     return nullptr;
 }
 
 GraphicsBuffer *GbmGraphicsBufferAllocator::allocate(const GraphicsBufferOptions &options)
 {
     if (options.software) {
         return allocateDumb(m_gbmDevice, options);
     }
 
     return allocateDmaBuf(m_gbmDevice, options);
 }
 
 GbmGraphicsBuffer::GbmGraphicsBuffer(DmaBufAttributes attributes, gbm_bo *handle)
     : m_bo(handle)
     , m_dmabufAttributes(std::move(attributes))
     , m_size(m_dmabufAttributes.width, m_dmabufAttributes.height)
     , m_hasAlphaChannel(alphaChannelFromDrmFormat(m_dmabufAttributes.format))
 {
 }
 
 GbmGraphicsBuffer::~GbmGraphicsBuffer()
 {
     unmap();
     gbm_bo_destroy(m_bo);
 }
 
 QSize GbmGraphicsBuffer::size() const
 {
     return m_size;
 }
 
 bool GbmGraphicsBuffer::hasAlphaChannel() const
 {
     return m_hasAlphaChannel;
 }
 
 const DmaBufAttributes *GbmGraphicsBuffer::dmabufAttributes() const
 {
     return &m_dmabufAttributes;
 }
 
 GraphicsBuffer::Map GbmGraphicsBuffer::map(MapFlags flags)
 {
     if (!m_mapPtr) {
         uint32_t access = 0;
         if (flags & MapFlag::Read) {
             access |= GBM_BO_TRANSFER_READ;
         }
         if (flags & MapFlag::Write) {
             access |= GBM_BO_TRANSFER_WRITE;
         }
         m_mapPtr = gbm_bo_map(m_bo, 0, 0, m_dmabufAttributes.width, m_dmabufAttributes.height, access, &m_mapStride, &m_mapData);
     }
     return Map{
         .data = m_mapPtr,
         .stride = m_mapStride,
     };
 }
 
 void GbmGraphicsBuffer::unmap()
 {
     if (m_mapPtr) {
         gbm_bo_unmap(m_bo, m_mapData);
         m_mapPtr = nullptr;
         m_mapData = nullptr;
     }
 }
 
 DumbGraphicsBuffer::DumbGraphicsBuffer(int drmFd, uint32_t handle, DmaBufAttributes attributes)
     : m_drmFd(drmFd)
     , m_handle(handle)
     , m_size(attributes.pitch[0] * attributes.height)
     , m_dmabufAttributes(std::move(attributes))
     , m_hasAlphaChannel(alphaChannelFromDrmFormat(m_dmabufAttributes.format))
 {
 }
 
 DumbGraphicsBuffer::~DumbGraphicsBuffer()
 {
     unmap();
 
     drm_mode_destroy_dumb destroyArgs{
         .handle = m_handle,
     };
     drmIoctl(m_drmFd, DRM_IOCTL_MODE_DESTROY_DUMB, &destroyArgs);
 }
 
 QSize DumbGraphicsBuffer::size() const
 {
     return QSize(m_dmabufAttributes.width, m_dmabufAttributes.height);
 }
 
 bool DumbGraphicsBuffer::hasAlphaChannel() const
 {
     return m_hasAlphaChannel;
 }
 
 const DmaBufAttributes *DumbGraphicsBuffer::dmabufAttributes() const
 {
     return &m_dmabufAttributes;
 }
 
 GraphicsBuffer::Map DumbGraphicsBuffer::map(MapFlags flags)
 {
     if (!m_data) {
         drm_mode_map_dumb mapArgs{
             .handle = m_handle,
         };
         if (drmIoctl(m_drmFd, DRM_IOCTL_MODE_MAP_DUMB, &mapArgs) != 0) {
             qCWarning(KWIN_CORE) << "DRM_IOCTL_MODE_MAP_DUMB failed:" << strerror(errno);
             return {};
         }
 
         void *address = mmap(nullptr, m_size, PROT_READ | PROT_WRITE, MAP_SHARED, m_drmFd, mapArgs.offset);
         if (address == MAP_FAILED) {
             qCWarning(KWIN_CORE) << "mmap() failed:" << strerror(errno);
             return {};
         }
 
         m_data = address;
     }
     return Map{
         .data = m_data,
         .stride = m_dmabufAttributes.pitch[0],
     };
 }
 
 void DumbGraphicsBuffer::unmap()
 {
     if (m_data) {
         munmap(m_data, m_size);
         m_data = nullptr;
     }
 }
 
 } // namespace KWin
 
 #include "gbmgraphicsbufferallocator.moc"
 #include "moc_gbmgraphicsbufferallocator.cpp"