[libcamera-devel] [PATCH v1 01/10] libcamera: pipeline: Add a platform configuration file helper

[Naushir Patuck]

Hi David,

Thank you for your feedback!

On Tue, 1 Nov 2022 at 11:43, David Plowman <david.plowman at raspberrypi.com>
wrote:

> Hi Naush
>
> Thanks for this patch!
>
> On Fri, 14 Oct 2022 at 14:18, Naushir Patuck via libcamera-devel
> <libcamera-devel at lists.libcamera.org> wrote:
> >
> > Add a new helper function PipelineHandler::configurationFile() that
> returns
> > the full path of a named configuration file. This configuration file may
> be read
> > by pipeline handlers for platform specific configuration parameters on
> > initialisation.
> >
> > The mechanism for searching for the configuration file is similar to the
> IPA
> > configuration file:
> >
> > - In the source tree if libcamera is not installed
> > - Otherwise in standard system locations (etc and share directories).
> >
> > When stored in the source tree, configuration files shall be located in
> a 'data'
> > subdirectory of their respective pipeline handler directory.
> >
> > Signed-off-by: Naushir Patuck <naush at raspberrypi.com>
> > ---
> >  include/libcamera/internal/pipeline_handler.h |  2 +
> >  src/libcamera/pipeline_handler.cpp            | 57 +++++++++++++++++++
> >  2 files changed, 59 insertions(+)
> >
> > diff --git a/include/libcamera/internal/pipeline_handler.h
> b/include/libcamera/internal/pipeline_handler.h
> > index b6139a88d421..6648975f15de 100644
> > --- a/include/libcamera/internal/pipeline_handler.h
> > +++ b/include/libcamera/internal/pipeline_handler.h
> > @@ -74,6 +74,8 @@ protected:
> >         virtual int queueRequestDevice(Camera *camera, Request *request)
> = 0;
> >         virtual void stopDevice(Camera *camera) = 0;
> >
> > +       std::string configurationFile(const std::string &name) const;
> > +
> >         CameraManager *manager_;
> >
> >  private:
> > diff --git a/src/libcamera/pipeline_handler.cpp
> b/src/libcamera/pipeline_handler.cpp
> > index 588a3db30e82..998dcece05f2 100644
> > --- a/src/libcamera/pipeline_handler.cpp
> > +++ b/src/libcamera/pipeline_handler.cpp
> > @@ -8,6 +8,7 @@
> >  #include "libcamera/internal/pipeline_handler.h"
> >
> >  #include <chrono>
> > +#include <sys/stat.h>
> >  #include <sys/sysmacros.h>
> >
> >  #include <libcamera/base/log.h>
> > @@ -625,6 +626,62 @@ void PipelineHandler::disconnect()
> >         }
> >  }
> >
> > +/**
> > + * \brief Retrieve the absolute path to a platform configuration file
> > + * \param[in] name The configuration file name
> > + *
> > + * This function locates a named platform configuration file and returns
> > + * its absolute path to the pipeline handler. It searches the following
> > + * directories, in order:
> > + *
> > + * - If libcamera is not installed, the src/libcamera/pipeline/
> directory within
> > + *   the source tree ; otherwise
> > + * - The system data (share/libcamera/pipeline/) directory.
> > + *
> > + * The system directories are not searched if libcamera is not
> installed.
> > + *
> > + * \return The full path to the pipeline handler configuration file, or
> an empty
> > + * string if no configuration file can be found
> > + */
> > +std::string PipelineHandler::configurationFile(const std::string &name)
> const
> > +{
> > +       struct stat statbuf;
> > +       int ret;
> > +
> > +       std::string root = utils::libcameraSourcePath();
> > +       if (!root.empty()) {
> > +               /*
> > +                * When libcamera is used before it is installed, load
> > +                * configuration files from the source directory. The
> > +                * configuration files are then located in the 'data'
> > +                * subdirectory of the corresponding IPA module.
> > +                */
> > +               std::string confDir = root +
> "src/libcamera/pipeline/data";
> > +
> > +               LOG(Pipeline, Info)
> > +                       << "libcamera is not installed. Loading platform
> configuration file from '"
> > +                       << confDir << "'";
> > +
> > +               std::string confPath = confDir + "/" + name;
> > +               ret = stat(confPath.c_str(), &statbuf);
> > +               if (ret == 0 && (statbuf.st_mode & S_IFMT) == S_IFREG)
>
> I guess I was just wondering slightly whether this is worth checking
> given that we fail with a helpful message anyway if we can't open the
> file, but it's fine like this too, so probably just ignore me!
>

This function is (mostly) a duplicate of what is used for the tuning file,
so I'll probably leave this check in to be consistent.

Regards,
Naush


>
> Reviewed-by: David Plowman <david.plowman at raspberrypi.com>
>
> Thanks!
> David
>
> > +                       return confPath;
> > +
> > +       } else {
> > +               /* Else look in the system locations. */
> > +               std::string confPath = std::string(LIBCAMERA_DATA_DIR) +
> "/pipeline/" + name;
> > +               ret = stat(confPath.c_str(), &statbuf);
> > +               if (ret == 0 && (statbuf.st_mode & S_IFMT) == S_IFREG)
> > +                       return confPath;
> > +       }
> > +
> > +       LOG(Pipeline, Error)
> > +               << "Configuration file '" << name
> > +               << "' not found for pipeline handler '" <<
> PipelineHandler::name() << "'";
> > +
> > +       return std::string();
> > +}
> > +
> >  /**
> >   * \var PipelineHandler::manager_
> >   * \brief The Camera manager associated with the pipeline handler
> > --
> > 2.25.1
> >
>
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