[libcamera-devel] [PATCH v2 2/3] android: camera_buffer: Map buffer in the first plane() call
Laurent Pinchart
laurent.pinchart at ideasonboard.com
Wed Aug 25 22:33:23 CEST 2021
Hi Hiro,
Thank you for the patch.
On Wed, Aug 25, 2021 at 08:02:45PM +0900, Hirokazu Honda wrote:
> On Wed, Aug 25, 2021 at 5:45 PM Jacopo Mondi wrote:
> > On Wed, Aug 25, 2021 at 01:44:09PM +0900, Hirokazu Honda wrote:
> > > CameraBuffer implementation maps a given buffer_handle_t in
> > > constructor. Mapping is redundant to only know the plane info like
> > > stride and offset. Mapping should be executed rater in the first
> > > plane() call.
> > >
> > > Signed-off-by: Hirokazu Honda <hiroh at chromium.org>
> > > ---
> > > src/android/mm/cros_camera_buffer.cpp | 71 ++++++++++++--------
> > > src/android/mm/generic_camera_buffer.cpp | 85 ++++++++++++++++--------
> > > 2 files changed, 101 insertions(+), 55 deletions(-)
> > >
> > > diff --git a/src/android/mm/cros_camera_buffer.cpp b/src/android/mm/cros_camera_buffer.cpp
> > > index 50732637..42546d87 100644
> > > --- a/src/android/mm/cros_camera_buffer.cpp
> > > +++ b/src/android/mm/cros_camera_buffer.cpp
> > > @@ -25,7 +25,7 @@ public:
> > > int flags);
> > > ~Private();
> > >
> > > - bool isValid() const { return valid_; }
> > > + bool isValid() const { return registered_; }
> > >
> > > unsigned int numPlanes() const;
> > >
> > > @@ -34,10 +34,12 @@ public:
> > > size_t jpegBufferSize(size_t maxJpegBufferSize) const;
> > >
> > > private:
> > > + bool map();
> >
> > void map();
> >
> > > +
> > > cros::CameraBufferManager *bufferManager_;
> > > buffer_handle_t handle_;
> > > unsigned int numPlanes_;
> > > - bool valid_;
> > > + bool mapped_;
> > > bool registered_;
> > > union {
> > > void *addr;
> > > @@ -50,7 +52,7 @@ CameraBuffer::Private::Private([[maybe_unused]] CameraBuffer *cameraBuffer,
> > > [[maybe_unused]] libcamera::PixelFormat pixelFormat,
> > > [[maybe_unused]] const libcamera::Size &size,
> > > [[maybe_unused]] int flags)
> > > - : handle_(camera3Buffer), numPlanes_(0), valid_(false),
> > > + : handle_(camera3Buffer), numPlanes_(0), mapped_(false),
> > > registered_(false)
> > > {
> > > bufferManager_ = cros::CameraBufferManager::GetInstance();
> > > @@ -63,36 +65,11 @@ CameraBuffer::Private::Private([[maybe_unused]] CameraBuffer *cameraBuffer,
> > >
> > > registered_ = true;
> > > numPlanes_ = bufferManager_->GetNumPlanes(camera3Buffer);
> > > - switch (numPlanes_) {
> > > - case 1: {
> > > - ret = bufferManager_->Lock(handle_, 0, 0, 0, 0, 0, &mem.addr);
> > > - if (ret) {
> > > - LOG(HAL, Error) << "Single plane buffer mapping failed";
> > > - return;
> > > - }
> > > - break;
> > > - }
> > > - case 2:
> > > - case 3: {
> > > - ret = bufferManager_->LockYCbCr(handle_, 0, 0, 0, 0, 0,
> > > - &mem.ycbcr);
> > > - if (ret) {
> > > - LOG(HAL, Error) << "YCbCr buffer mapping failed";
> > > - return;
> > > - }
> > > - break;
> > > - }
> > > - default:
> > > - LOG(HAL, Error) << "Invalid number of planes: " << numPlanes_;
> > > - return;
> > > - }
> > > -
> > > - valid_ = true;
> > > }
> > >
> > > CameraBuffer::Private::~Private()
> > > {
> > > - if (valid_)
> > > + if (mapped_)
> > > bufferManager_->Unlock(handle_);
> > > if (registered_)
> > > bufferManager_->Deregister(handle_);
> > > @@ -105,6 +82,12 @@ unsigned int CameraBuffer::Private::numPlanes() const
> > >
> > > Span<uint8_t> CameraBuffer::Private::plane(unsigned int plane)
> > > {
> > > + if (!mapped_) {
> > > + mapped_ = map();
> > > + if (!mapped_)
> > > + return {};
> > > + }
> >
> > if (!mapped_)
> > map();
> > if (!mapped_);
> > return {};
> > > +
> > > void *addr;
> > >
> > > switch (numPlanes()) {
> > > @@ -134,4 +117,34 @@ size_t CameraBuffer::Private::jpegBufferSize([[maybe_unused]] size_t maxJpegBuff
> > > return bufferManager_->GetPlaneSize(handle_, 0);
> > > }
> > >
> > > +bool CameraBuffer::Private::map()
> >
> > void
> > > +{
> > > + int ret;
> > > + switch (numPlanes_) {
> > > + case 1: {
> > > + ret = bufferManager_->Lock(handle_, 0, 0, 0, 0, 0, &mem.addr);
> > > + if (ret) {
> > > + LOG(HAL, Error) << "Single plane buffer mapping failed";
> > > + return false;
> >
> > return;
> > > + }
> > > + break;
> > > + }
> > > + case 2:
> > > + case 3: {
> > > + ret = bufferManager_->LockYCbCr(handle_, 0, 0, 0, 0, 0,
> > > + &mem.ycbcr);
> > > + if (ret) {
> > > + LOG(HAL, Error) << "YCbCr buffer mapping failed";
> > > + return false;
> >
> > Ditto
> >
> > > + }
> > > + break;
> > > + }
> > > + default:
> > > + LOG(HAL, Error) << "Invalid number of planes: " << numPlanes_;
> > > + return false;
> >
> > Ditto
> >
> > > + }
> > > +
> > > + return true;
> >
> > mapped_ = true;
> > > +}
> > > +
> > > PUBLIC_CAMERA_BUFFER_IMPLEMENTATION
> > > diff --git a/src/android/mm/generic_camera_buffer.cpp b/src/android/mm/generic_camera_buffer.cpp
> > > index 0bfdc2ba..37868d26 100644
> > > --- a/src/android/mm/generic_camera_buffer.cpp
> > > +++ b/src/android/mm/generic_camera_buffer.cpp
> > > @@ -37,6 +37,17 @@ public:
> > > size_t jpegBufferSize(size_t maxJpegBufferSize) const;
> > >
> > > private:
> > > + struct PlaneInfo {
> > > + unsigned int offset;
> > > + unsigned int size;
> > > + };
> > > +
> > > + bool map();
> > > +
> > > + int fd_;
> > > + int flags_;
> > > + off_t bufferLength_;
> > > + std::vector<PlaneInfo> planeInfo_;
> >
> > Can't you use a mapped_ like the cros implementation ?
> >
> > > /* \todo Remove planes_ when it will be added to MappedBuffer */
> > > std::vector<Span<uint8_t>> planes_;
> > > };
> > > @@ -45,6 +56,7 @@ CameraBuffer::Private::Private([[maybe_unused]] CameraBuffer *cameraBuffer,
> > > buffer_handle_t camera3Buffer,
> > > libcamera::PixelFormat pixelFormat,
> > > const libcamera::Size &size, int flags)
> > > + : fd_(-1), flags_(flags)
> > > {
> > > error_ = 0;
> > > /*
> > > @@ -52,19 +64,18 @@ CameraBuffer::Private::Private([[maybe_unused]] CameraBuffer *cameraBuffer,
> > > * now that the buffer is backed by a single dmabuf, with planes being
> > > * stored contiguously.
> > > */
> > > - int fd = -1;
> > > for (int i = 0; i < camera3Buffer->numFds; i++) {
> > > if (camera3Buffer->data[i] == -1 ||
> > > - camera3Buffer->data[i] == fd) {
> > > + camera3Buffer->data[i] == fd_) {
> > > continue;
> > > }
> > >
> > > - if (fd != -1)
> > > + if (fd_ != -1)
> > > LOG(HAL, Fatal) << "Discontiguous planes are not supported";
> > > - fd = camera3Buffer->data[i];
> > > + fd_ = camera3Buffer->data[i];
> > > }
> > >
> > > - if (fd != -1) {
> > > + if (fd_ != -1) {
> > > error_ = -EINVAL;
> > > LOG(HAL, Error) << "No valid file descriptor";
> > > return;
> > > @@ -78,23 +89,16 @@ CameraBuffer::Private::Private([[maybe_unused]] CameraBuffer *cameraBuffer,
> > > return;
> > > }
> > >
> > > - off_t bufferLength = lseek(fd, 0, SEEK_END);
> > > + size_t bufferLength = lseek(fd_, 0, SEEK_END);
s/size_t/off_t/ or you'll have a warning with the next line.
> > > if (bufferLength < 0) {
> > > - error_ = -errno;
> > > + error_ = -EINVAL;
> >
> > Why this change ?
> >
> > > LOG(HAL, Error) << "Failed to get buffer length";
> > > return;
> > > }
> > >
> > > - void *address = mmap(nullptr, bufferLength, flags, MAP_SHARED, fd, 0);
> > > - if (address == MAP_FAILED) {
> > > - error_ = -errno;
> > > - LOG(HAL, Error) << "Failed to mmap plane";
> > > - return;
> > > - }
> > > - maps_.emplace_back(static_cast<uint8_t *>(address), bufferLength);
> > > -
> > > const unsigned int numPlanes = info.numPlanes();
> > > - planes_.resize(numPlanes);
> > > + planeInfo_.resize(numPlanes);
> > > +
> > > unsigned int offset = 0;
> > > for (unsigned int i = 0; i < numPlanes; ++i) {
> > > /*
> > > @@ -106,17 +110,17 @@ CameraBuffer::Private::Private([[maybe_unused]] CameraBuffer *cameraBuffer,
> > > const unsigned int planeSize =
> > > stride * ((size.height + vertSubSample - 1) / vertSubSample);
> > >
> > > - planes_[i] = libcamera::Span<uint8_t>(
> > > - static_cast<uint8_t *>(address) + offset, planeSize);
> > > + planeInfo_[i].offset = offset;
> > > + planeInfo_[i].size = planeSize;
> > >
> > > if (bufferLength < offset + planeSize) {
> > > - error_ = -EINVAL;
> > > - LOG(HAL, Error) << "Plane " << i << " is out of buffer"
> > > - << ", buffer length=" << bufferLength
> > > - << ", offset=" << offset
> > > - << ", size=" << planeSize;
> > > + LOG(HAL, Error) << "Plane " << i << " is out of buffer:"
> > > + << " plane offset=" << offset
> > > + << ", plane size=" << planeSize
> > > + << ", buffer length=" << bufferLength;
> > > return;
> > > }
> > > +
> > > offset += planeSize;
> > > }
> > > }
> > > @@ -127,11 +131,14 @@ CameraBuffer::Private::~Private()
> > >
> > > unsigned int CameraBuffer::Private::numPlanes() const
> > > {
> > > - return planes_.size();
> > > + return planeInfo_.size();
> > > }
> > >
> > > Span<uint8_t> CameraBuffer::Private::plane(unsigned int plane)
> > > {
> > > + if (planes_.empty() && !map())
> > > + return {};
> > > +
> >
> > And repeat the pattern used in cros implementation using a mapped_
> > class variable to keep the two implementation similar ?
> >
> > > if (plane >= planes_.size())
> > > return {};
> > >
> > > @@ -140,8 +147,34 @@ Span<uint8_t> CameraBuffer::Private::plane(unsigned int plane)
> > >
> > > size_t CameraBuffer::Private::jpegBufferSize(size_t maxJpegBufferSize) const
> > > {
> > > - return std::min<unsigned int>(maps_[0].size(),
> > > - maxJpegBufferSize);
> > > + if (maps_.empty()) {
> > > + ASSERT(bufferLength_ >= 0);
> > > + return std::min<unsigned int>(bufferLength_, maxJpegBufferSize);
> > > + }
> > > +
> > > + return std::min<unsigned int>(maps_[0].size(), maxJpegBufferSize);
Given that maps_[0].size() == bufferLength_, I think this whole function
can be simplified to
return std::min<unsigned int>(bufferLength_, maxJpegBufferSize);
> > > +}
> > > +
> > > +bool CameraBuffer::Private::map()
> > > +{
> > > + ASSERT(fd_ != -1);
> >
> > Shouldn't we fail earlier then ?
> >
> > > + ASSERT(bufferLength_ >= 0);
> > > +
> > > + void *address = mmap(nullptr, bufferLength_, flags_, MAP_SHARED, fd_, 0);
> > > + if (address == MAP_FAILED) {
> > > + error_ = -errno;
> > > + LOG(HAL, Error) << "Failed to mmap plane";
> > > + return false;
> > > + }
> > > + maps_.emplace_back(static_cast<uint8_t *>(address), bufferLength_);
> > > +
> > > + planes_.reserve(planeInfo_.size());
> > > + for (const auto &info : planeInfo_) {
> > > + planes_.emplace_back(
> > > + static_cast<uint8_t *>(address) + info.offset, info.size);
> > > + }
> >
> > Can't this be done on costruction as it just basically transfer the
> > information stored in planeInfo into planes_ rendering planeInfo_ just
> > a temporary storage ?
>
> address is needed to fill planes_ correctly.
> planeInfo_ is used in stride/offset/size() in the next patch. Since it
> is useful even in this patch, I introduced it from this patch.
Another option would be to store the mmap()ed address in a single void
*address_ class member, drop maps_, and change the plane() function to
Span<uint8_t> CameraBuffer::Private::plane(unsigned int plane)
{
if (plane >= planeInfo_.size())
return {};
const PlaneInfo &info = planeInfo_[plane];
return { static_cast<uint8_t *>(address_) + info.offset, info.size };
}
Yet another option would be to store { info.offset, info.size } in planes_
in the constructor, and then add address to the offset in this function.
> > > +
> > > + return true;
> > > }
> > >
> > > PUBLIC_CAMERA_BUFFER_IMPLEMENTATION
--
Regards,
Laurent Pinchart
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