[libcamera-devel,v1,04/10] pipeline: raspberrypi: Read config parameters from a file
diff mbox series

Message ID 20221014131846.27169-5-naush@raspberrypi.com
State Superseded
Headers show
Series
  • Raspberry Pi: Platform configuration and buffer allocation improvements
Related show

Commit Message

Naushir Patuck Oct. 14, 2022, 1:18 p.m. UTC 
Read the platform configuration parameters from default.json config file. Use
the PipelineHandler::configurationFile() helper to determine the full path of
the file. The default.json filename can be overridden by the user setting the
LIBCAMERA_RPI_CONFIG_FILE environment variable giving the full path of the
custom file.

Add config parameter validation to ensure bad parameters cannot cause the
pipeline handler to stop working.

Currently three parameters are available through the json file:

"min_unicam_buffers"
The minimum number of internal Unicam buffers to allocate.

"min_total_unicam_buffers"
The minimum number of internal + external Unicam buffers that must be allocated.

"num_output0_buffers"
Number of internal ISP Output0 buffers to allocate.

Signed-off-by: Naushir Patuck <naush@raspberrypi.com>
---
 .../pipeline/raspberrypi/data/default.json    | 20 +++++++
 .../pipeline/raspberrypi/data/meson.build     |  8 +++
 .../pipeline/raspberrypi/meson.build          |  2 +
 .../pipeline/raspberrypi/raspberrypi.cpp      | 56 +++++++++++++++++++
 4 files changed, 86 insertions(+)
 create mode 100644 src/libcamera/pipeline/raspberrypi/data/default.json
 create mode 100644 src/libcamera/pipeline/raspberrypi/data/meson.build

Comments

David Plowman Nov. 1, 2022, 12:01 p.m. UTC | #1 
Hi Naush

Thanks for the patch!

On Fri, 14 Oct 2022 at 14:19, Naushir Patuck via libcamera-devel
<libcamera-devel@lists.libcamera.org> wrote:
>
> Read the platform configuration parameters from default.json config file. Use
> the PipelineHandler::configurationFile() helper to determine the full path of
> the file. The default.json filename can be overridden by the user setting the
> LIBCAMERA_RPI_CONFIG_FILE environment variable giving the full path of the
> custom file.
>
> Add config parameter validation to ensure bad parameters cannot cause the
> pipeline handler to stop working.
>
> Currently three parameters are available through the json file:
>
> "min_unicam_buffers"
> The minimum number of internal Unicam buffers to allocate.
>
> "min_total_unicam_buffers"
> The minimum number of internal + external Unicam buffers that must be allocated.
>
> "num_output0_buffers"
> Number of internal ISP Output0 buffers to allocate.
>
> Signed-off-by: Naushir Patuck <naush@raspberrypi.com>
> ---
>  .../pipeline/raspberrypi/data/default.json    | 20 +++++++
>  .../pipeline/raspberrypi/data/meson.build     |  8 +++
>  .../pipeline/raspberrypi/meson.build          |  2 +
>  .../pipeline/raspberrypi/raspberrypi.cpp      | 56 +++++++++++++++++++
>  4 files changed, 86 insertions(+)
>  create mode 100644 src/libcamera/pipeline/raspberrypi/data/default.json
>  create mode 100644 src/libcamera/pipeline/raspberrypi/data/meson.build
>
> diff --git a/src/libcamera/pipeline/raspberrypi/data/default.json b/src/libcamera/pipeline/raspberrypi/data/default.json
> new file mode 100644
> index 000000000000..d709e31850af
> --- /dev/null
> +++ b/src/libcamera/pipeline/raspberrypi/data/default.json
> @@ -0,0 +1,20 @@
> +{
> +        "version": 1.0,
> +        "target": "bcm2835",
> +
> +        "pipeline_handler":
> +        {
> +                # The minimum number of internal buffers to be allocated for Unicam.
> +                # This value must be greater than 0, but less than or equal to min_total_unicam_buffers.

Are we allowed comments in json files now? That's nice! Perhaps we
should put some in our tuning files...

> +                "min_unicam_buffers": 2,
> +
> +                # The minimum total (internal + external) buffer count used for Unicam.
> +                # The number of internal buffers allocated for Unicam is given by:
> +                # internal buffer count = max(min_unicam_buffers,
> +                #                             min_total_unicam_buffers - external buffer count)
> +                "min_total_unicam_buffers": 4,
> +
> +                # The number of internal buffers used for ISP Output0. This must be set to 1.
> +                "num_output0_buffers": 1
> +        }
> +}
> diff --git a/src/libcamera/pipeline/raspberrypi/data/meson.build b/src/libcamera/pipeline/raspberrypi/data/meson.build
> new file mode 100644
> index 000000000000..232f8b43c5fd
> --- /dev/null
> +++ b/src/libcamera/pipeline/raspberrypi/data/meson.build
> @@ -0,0 +1,8 @@
> +# SPDX-License-Identifier: CC0-1.0
> +
> +conf_files = files([
> +    'default.json',
> +])
> +
> +install_data(conf_files,
> +             install_dir : libcamera_datadir / 'pipeline/raspberrypi')
> diff --git a/src/libcamera/pipeline/raspberrypi/meson.build b/src/libcamera/pipeline/raspberrypi/meson.build
> index f1a2f5ee72c2..48235f887501 100644
> --- a/src/libcamera/pipeline/raspberrypi/meson.build
> +++ b/src/libcamera/pipeline/raspberrypi/meson.build
> @@ -5,3 +5,5 @@ libcamera_sources += files([
>      'raspberrypi.cpp',
>      'rpi_stream.cpp',
>  ])
> +
> +subdir('data')
> diff --git a/src/libcamera/pipeline/raspberrypi/raspberrypi.cpp b/src/libcamera/pipeline/raspberrypi/raspberrypi.cpp
> index 450029197b11..bac7a66ba900 100644
> --- a/src/libcamera/pipeline/raspberrypi/raspberrypi.cpp
> +++ b/src/libcamera/pipeline/raspberrypi/raspberrypi.cpp
> @@ -14,6 +14,7 @@
>  #include <unordered_set>
>  #include <utility>
>
> +#include <libcamera/base/file.h>
>  #include <libcamera/base/shared_fd.h>
>  #include <libcamera/base/utils.h>
>
> @@ -40,6 +41,7 @@
>  #include "libcamera/internal/media_device.h"
>  #include "libcamera/internal/pipeline_handler.h"
>  #include "libcamera/internal/v4l2_videodevice.h"
> +#include "libcamera/internal/yaml_parser.h"
>
>  #include "dma_heaps.h"
>  #include "rpi_stream.h"
> @@ -301,6 +303,7 @@ public:
>         };
>
>         Config config_;
> +       unsigned int numUnicamBuffers;
>
>  private:
>         void checkRequestCompleted();
> @@ -1140,6 +1143,19 @@ int PipelineHandlerRPi::queueRequestDevice(Camera *camera, Request *request)
>                          */
>                         stream->setExternalBuffer(buffer);
>                 }
> +
> +               if (!buffer) {
> +                       if (stream == &data->isp_[Isp::Output0] && !data->config_.numOutput0Buffers) {
> +                               LOG(RPI, Error) << "Output0 buffer must be provided in the request.";
> +                               return -EINVAL;
> +                       }
> +
> +                       if (stream == &data->unicam_[Unicam::Image] && !data->numUnicamBuffers) {
> +                               LOG(RPI, Error) << "Unicam Image buffer must be provided in the request.";
> +                               return -EINVAL;
> +                       }
> +               }
> +
>                 /*
>                  * If no buffer is provided by the request for this stream, we
>                  * queue a nullptr to the stream to signify that it must use an
> @@ -1398,6 +1414,7 @@ int PipelineHandlerRPi::registerCamera(MediaDevice *unicam, MediaDevice *isp, Me
>  int PipelineHandlerRPi::configurePipelineHandler(RPiCameraData *data)
>  {
>         RPiCameraData::Config &config = data->config_;
> +       std::string filename;
>
>         config = {
>                 .minUnicamBuffers = 2,
> @@ -1405,6 +1422,44 @@ int PipelineHandlerRPi::configurePipelineHandler(RPiCameraData *data)
>                 .numOutput0Buffers = 1,
>         };
>
> +       char const *configFromEnv = utils::secure_getenv("LIBCAMERA_RPI_CONFIG_FILE");
> +       if (!configFromEnv || *configFromEnv == '\0')
> +               filename = configurationFile("raspberrypi/default.json");

I was a teeny bit nervous that in the non-installed case it might come
back with "libcamera/src/ipa/raspberrypi/data/raspberrypi/default.json"
which would be the wrong thing? Maybe you could just put my mind at
ease here...

> +       else
> +               filename = std::string(configFromEnv);
> +
> +       if (filename.empty())
> +               return -EINVAL;
> +
> +       File file(filename);
> +       if (!file.open(File::OpenModeFlag::ReadOnly)) {
> +               LOG(RPI, Error) << "Failed to open configuration file '" << filename << "'";
> +               return -EIO;
> +       }
> +
> +       LOG(RPI, Info) << "Using configuration file '" << filename << "'";
> +
> +       std::unique_ptr<YamlObject> root = YamlParser::parse(file);
> +       if (!root) {
> +               LOG(RPI, Error) << "Failed to parse configuration file, using defaults!";
> +               return -EINVAL;
> +       }
> +
> +       ASSERT((*root)["version"].get<double>() == 1.0);
> +
> +       const YamlObject &phConfig = (*root)["pipeline_handler"];
> +       config.minUnicamBuffers =
> +               phConfig["min_unicam_buffers"].get<unsigned int>(config.minUnicamBuffers);
> +       config.minTotalUnicamBuffers =
> +               phConfig["min_total_unicam_buffers"].get<unsigned int>(config.minTotalUnicamBuffers);
> +       config.numOutput0Buffers =
> +               phConfig["num_output0_buffers"].get<unsigned int>(config.numOutput0Buffers);
> +
> +       if (config.minTotalUnicamBuffers < config.minUnicamBuffers || config.minTotalUnicamBuffers < 1) {

I wonder a little bit about splitting up all these little checks so
that we can be really specific in the error message? But I'm not too
fussed.

Subject to a check on that pathname question I had:

Reviewed-by: David Plowman <david.plowman@raspberrypi.com>

Thanks!
David

> +               LOG(RPI, Error) << "Invalid Unicam buffer configuration used!";
> +               return -EINVAL;
> +       }
> +
>         return 0;
>  }
>
> @@ -1471,6 +1526,7 @@ int PipelineHandlerRPi::prepareBuffers(Camera *camera)
>                          */
>                         numBuffers = std::max<int>(data->config_.minUnicamBuffers,
>                                                    minBuffers - numRawBuffers);
> +                       data->numUnicamBuffers = numBuffers;
>                 } else if (stream == &data->isp_[Isp::Input]) {
>                         /*
>                          * ISP input buffers are imported from Unicam, so follow
> --
> 2.25.1
>
Naushir Patuck Nov. 29, 2022, 10:44 a.m. UTC | #2 
Hi David,

Thank you for your feedback

On Tue, 1 Nov 2022 at 12:01, David Plowman <david.plowman@raspberrypi.com>
wrote:

> Hi Naush
>
> Thanks for the patch!
>
> On Fri, 14 Oct 2022 at 14:19, Naushir Patuck via libcamera-devel
> <libcamera-devel@lists.libcamera.org> wrote:
> >
> > Read the platform configuration parameters from default.json config
> file. Use
> > the PipelineHandler::configurationFile() helper to determine the full
> path of
> > the file. The default.json filename can be overridden by the user
> setting the
> > LIBCAMERA_RPI_CONFIG_FILE environment variable giving the full path of
> the
> > custom file.
> >
> > Add config parameter validation to ensure bad parameters cannot cause the
> > pipeline handler to stop working.
> >
> > Currently three parameters are available through the json file:
> >
> > "min_unicam_buffers"
> > The minimum number of internal Unicam buffers to allocate.
> >
> > "min_total_unicam_buffers"
> > The minimum number of internal + external Unicam buffers that must be
> allocated.
> >
> > "num_output0_buffers"
> > Number of internal ISP Output0 buffers to allocate.
> >
> > Signed-off-by: Naushir Patuck <naush@raspberrypi.com>
> > ---
> >  .../pipeline/raspberrypi/data/default.json    | 20 +++++++
> >  .../pipeline/raspberrypi/data/meson.build     |  8 +++
> >  .../pipeline/raspberrypi/meson.build          |  2 +
> >  .../pipeline/raspberrypi/raspberrypi.cpp      | 56 +++++++++++++++++++
> >  4 files changed, 86 insertions(+)
> >  create mode 100644 src/libcamera/pipeline/raspberrypi/data/default.json
> >  create mode 100644 src/libcamera/pipeline/raspberrypi/data/meson.build
> >
> > diff --git a/src/libcamera/pipeline/raspberrypi/data/default.json
> b/src/libcamera/pipeline/raspberrypi/data/default.json
> > new file mode 100644
> > index 000000000000..d709e31850af
> > --- /dev/null
> > +++ b/src/libcamera/pipeline/raspberrypi/data/default.json
> > @@ -0,0 +1,20 @@
> > +{
> > +        "version": 1.0,
> > +        "target": "bcm2835",
> > +
> > +        "pipeline_handler":
> > +        {
> > +                # The minimum number of internal buffers to be
> allocated for Unicam.
> > +                # This value must be greater than 0, but less than or
> equal to min_total_unicam_buffers.
>
> Are we allowed comments in json files now? That's nice! Perhaps we
> should put some in our tuning files...
>
> > +                "min_unicam_buffers": 2,
> > +
> > +                # The minimum total (internal + external) buffer count
> used for Unicam.
> > +                # The number of internal buffers allocated for Unicam
> is given by:
> > +                # internal buffer count = max(min_unicam_buffers,
> > +                #                             min_total_unicam_buffers
> - external buffer count)
> > +                "min_total_unicam_buffers": 4,
> > +
> > +                # The number of internal buffers used for ISP Output0.
> This must be set to 1.
> > +                "num_output0_buffers": 1
> > +        }
> > +}
> > diff --git a/src/libcamera/pipeline/raspberrypi/data/meson.build
> b/src/libcamera/pipeline/raspberrypi/data/meson.build
> > new file mode 100644
> > index 000000000000..232f8b43c5fd
> > --- /dev/null
> > +++ b/src/libcamera/pipeline/raspberrypi/data/meson.build
> > @@ -0,0 +1,8 @@
> > +# SPDX-License-Identifier: CC0-1.0
> > +
> > +conf_files = files([
> > +    'default.json',
> > +])
> > +
> > +install_data(conf_files,
> > +             install_dir : libcamera_datadir / 'pipeline/raspberrypi')
> > diff --git a/src/libcamera/pipeline/raspberrypi/meson.build
> b/src/libcamera/pipeline/raspberrypi/meson.build
> > index f1a2f5ee72c2..48235f887501 100644
> > --- a/src/libcamera/pipeline/raspberrypi/meson.build
> > +++ b/src/libcamera/pipeline/raspberrypi/meson.build
> > @@ -5,3 +5,5 @@ libcamera_sources += files([
> >      'raspberrypi.cpp',
> >      'rpi_stream.cpp',
> >  ])
> > +
> > +subdir('data')
> > diff --git a/src/libcamera/pipeline/raspberrypi/raspberrypi.cpp
> b/src/libcamera/pipeline/raspberrypi/raspberrypi.cpp
> > index 450029197b11..bac7a66ba900 100644
> > --- a/src/libcamera/pipeline/raspberrypi/raspberrypi.cpp
> > +++ b/src/libcamera/pipeline/raspberrypi/raspberrypi.cpp
> > @@ -14,6 +14,7 @@
> >  #include <unordered_set>
> >  #include <utility>
> >
> > +#include <libcamera/base/file.h>
> >  #include <libcamera/base/shared_fd.h>
> >  #include <libcamera/base/utils.h>
> >
> > @@ -40,6 +41,7 @@
> >  #include "libcamera/internal/media_device.h"
> >  #include "libcamera/internal/pipeline_handler.h"
> >  #include "libcamera/internal/v4l2_videodevice.h"
> > +#include "libcamera/internal/yaml_parser.h"
> >
> >  #include "dma_heaps.h"
> >  #include "rpi_stream.h"
> > @@ -301,6 +303,7 @@ public:
> >         };
> >
> >         Config config_;
> > +       unsigned int numUnicamBuffers;
> >
> >  private:
> >         void checkRequestCompleted();
> > @@ -1140,6 +1143,19 @@ int PipelineHandlerRPi::queueRequestDevice(Camera
> *camera, Request *request)
> >                          */
> >                         stream->setExternalBuffer(buffer);
> >                 }
> > +
> > +               if (!buffer) {
> > +                       if (stream == &data->isp_[Isp::Output0] &&
> !data->config_.numOutput0Buffers) {
> > +                               LOG(RPI, Error) << "Output0 buffer must
> be provided in the request.";
> > +                               return -EINVAL;
> > +                       }
> > +
> > +                       if (stream == &data->unicam_[Unicam::Image] &&
> !data->numUnicamBuffers) {
> > +                               LOG(RPI, Error) << "Unicam Image buffer
> must be provided in the request.";
> > +                               return -EINVAL;
> > +                       }
> > +               }
> > +
> >                 /*
> >                  * If no buffer is provided by the request for this
> stream, we
> >                  * queue a nullptr to the stream to signify that it must
> use an
> > @@ -1398,6 +1414,7 @@ int PipelineHandlerRPi::registerCamera(MediaDevice
> *unicam, MediaDevice *isp, Me
> >  int PipelineHandlerRPi::configurePipelineHandler(RPiCameraData *data)
> >  {
> >         RPiCameraData::Config &config = data->config_;
> > +       std::string filename;
> >
> >         config = {
> >                 .minUnicamBuffers = 2,
> > @@ -1405,6 +1422,44 @@ int
> PipelineHandlerRPi::configurePipelineHandler(RPiCameraData *data)
> >                 .numOutput0Buffers = 1,
> >         };
> >
> > +       char const *configFromEnv =
> utils::secure_getenv("LIBCAMERA_RPI_CONFIG_FILE");
> > +       if (!configFromEnv || *configFromEnv == '\0')
> > +               filename = configurationFile("raspberrypi/default.json");
>
> I was a teeny bit nervous that in the non-installed case it might come
> back with "libcamera/src/ipa/raspberrypi/data/raspberrypi/default.json"
> which would be the wrong thing? Maybe you could just put my mind at
> ease here...
>

It should load things from
"libcamera/src/libcamera/pipeline/data/raspberrypi/default.json",
but I ought to check this again to make sure!

However, that does lead to some awkwardness, perhaps it should be read from
 "libcamera/src/libcamera/pipeline/raspberrypi/data/default.json" to be
consistent with
the ipa config files...?



>
> > +       else
> > +               filename = std::string(configFromEnv);
> > +
> > +       if (filename.empty())
> > +               return -EINVAL;
> > +
> > +       File file(filename);
> > +       if (!file.open(File::OpenModeFlag::ReadOnly)) {
> > +               LOG(RPI, Error) << "Failed to open configuration file '"
> << filename << "'";
> > +               return -EIO;
> > +       }
> > +
> > +       LOG(RPI, Info) << "Using configuration file '" << filename <<
> "'";
> > +
> > +       std::unique_ptr<YamlObject> root = YamlParser::parse(file);
> > +       if (!root) {
> > +               LOG(RPI, Error) << "Failed to parse configuration file,
> using defaults!";
> > +               return -EINVAL;
> > +       }
> > +
> > +       ASSERT((*root)["version"].get<double>() == 1.0);
> > +
> > +       const YamlObject &phConfig = (*root)["pipeline_handler"];
> > +       config.minUnicamBuffers =
> > +               phConfig["min_unicam_buffers"].get<unsigned
> int>(config.minUnicamBuffers);
> > +       config.minTotalUnicamBuffers =
> > +               phConfig["min_total_unicam_buffers"].get<unsigned
> int>(config.minTotalUnicamBuffers);
> > +       config.numOutput0Buffers =
> > +               phConfig["num_output0_buffers"].get<unsigned
> int>(config.numOutput0Buffers);
> > +
> > +       if (config.minTotalUnicamBuffers < config.minUnicamBuffers ||
> config.minTotalUnicamBuffers < 1) {
>
> I wonder a little bit about splitting up all these little checks so
> that we can be really specific in the error message? But I'm not too
> fussed.
>

Good point, I will split this up.

Regards,
Naush


>
> Subject to a check on that pathname question I had:
>
> Reviewed-by: David Plowman <david.plowman@raspberrypi.com>
>
> Thanks!
> David
>
> > +               LOG(RPI, Error) << "Invalid Unicam buffer configuration
> used!";
> > +               return -EINVAL;
> > +       }
> > +
> >         return 0;
> >  }
> >
> > @@ -1471,6 +1526,7 @@ int PipelineHandlerRPi::prepareBuffers(Camera
> *camera)
> >                          */
> >                         numBuffers =
> std::max<int>(data->config_.minUnicamBuffers,
> >                                                    minBuffers -
> numRawBuffers);
> > +                       data->numUnicamBuffers = numBuffers;
> >                 } else if (stream == &data->isp_[Isp::Input]) {
> >                         /*
> >                          * ISP input buffers are imported from Unicam,
> so follow
> > --
> > 2.25.1
> >
>

Patch
diff mbox series 

diff --git a/src/libcamera/pipeline/raspberrypi/data/default.json b/src/libcamera/pipeline/raspberrypi/data/default.json
new file mode 100644
index 000000000000..d709e31850af
--- /dev/null
+++ b/src/libcamera/pipeline/raspberrypi/data/default.json
@@ -0,0 +1,20 @@ 
+{
+        "version": 1.0,
+        "target": "bcm2835",
+
+        "pipeline_handler":
+        {
+                # The minimum number of internal buffers to be allocated for Unicam.
+                # This value must be greater than 0, but less than or equal to min_total_unicam_buffers.
+                "min_unicam_buffers": 2,
+
+                # The minimum total (internal + external) buffer count used for Unicam.
+                # The number of internal buffers allocated for Unicam is given by:
+                # internal buffer count = max(min_unicam_buffers,
+                #                             min_total_unicam_buffers - external buffer count)
+                "min_total_unicam_buffers": 4,
+                
+                # The number of internal buffers used for ISP Output0. This must be set to 1.
+                "num_output0_buffers": 1
+        }
+}
diff --git a/src/libcamera/pipeline/raspberrypi/data/meson.build b/src/libcamera/pipeline/raspberrypi/data/meson.build
new file mode 100644
index 000000000000..232f8b43c5fd
--- /dev/null
+++ b/src/libcamera/pipeline/raspberrypi/data/meson.build
@@ -0,0 +1,8 @@ 
+# SPDX-License-Identifier: CC0-1.0
+
+conf_files = files([
+    'default.json',
+])
+
+install_data(conf_files,
+             install_dir : libcamera_datadir / 'pipeline/raspberrypi')
diff --git a/src/libcamera/pipeline/raspberrypi/meson.build b/src/libcamera/pipeline/raspberrypi/meson.build
index f1a2f5ee72c2..48235f887501 100644
--- a/src/libcamera/pipeline/raspberrypi/meson.build
+++ b/src/libcamera/pipeline/raspberrypi/meson.build
@@ -5,3 +5,5 @@  libcamera_sources += files([
     'raspberrypi.cpp',
     'rpi_stream.cpp',
 ])
+
+subdir('data')
diff --git a/src/libcamera/pipeline/raspberrypi/raspberrypi.cpp b/src/libcamera/pipeline/raspberrypi/raspberrypi.cpp
index 450029197b11..bac7a66ba900 100644
--- a/src/libcamera/pipeline/raspberrypi/raspberrypi.cpp
+++ b/src/libcamera/pipeline/raspberrypi/raspberrypi.cpp
@@ -14,6 +14,7 @@ 
 #include <unordered_set>
 #include <utility>
 
+#include <libcamera/base/file.h>
 #include <libcamera/base/shared_fd.h>
 #include <libcamera/base/utils.h>
 
@@ -40,6 +41,7 @@ 
 #include "libcamera/internal/media_device.h"
 #include "libcamera/internal/pipeline_handler.h"
 #include "libcamera/internal/v4l2_videodevice.h"
+#include "libcamera/internal/yaml_parser.h"
 
 #include "dma_heaps.h"
 #include "rpi_stream.h"
@@ -301,6 +303,7 @@  public:
 	};
 
 	Config config_;
+	unsigned int numUnicamBuffers;
 
 private:
 	void checkRequestCompleted();
@@ -1140,6 +1143,19 @@  int PipelineHandlerRPi::queueRequestDevice(Camera *camera, Request *request)
 			 */
 			stream->setExternalBuffer(buffer);
 		}
+
+		if (!buffer) {
+			if (stream == &data->isp_[Isp::Output0] && !data->config_.numOutput0Buffers) {
+				LOG(RPI, Error) << "Output0 buffer must be provided in the request.";
+				return -EINVAL;
+			}
+
+			if (stream == &data->unicam_[Unicam::Image] && !data->numUnicamBuffers) {
+				LOG(RPI, Error) << "Unicam Image buffer must be provided in the request.";
+				return -EINVAL;
+			}
+		}
+
 		/*
 		 * If no buffer is provided by the request for this stream, we
 		 * queue a nullptr to the stream to signify that it must use an
@@ -1398,6 +1414,7 @@  int PipelineHandlerRPi::registerCamera(MediaDevice *unicam, MediaDevice *isp, Me
 int PipelineHandlerRPi::configurePipelineHandler(RPiCameraData *data)
 {
 	RPiCameraData::Config &config = data->config_;
+	std::string filename;
 
 	config = {
 		.minUnicamBuffers = 2,
@@ -1405,6 +1422,44 @@  int PipelineHandlerRPi::configurePipelineHandler(RPiCameraData *data)
 		.numOutput0Buffers = 1,
 	};
 
+	char const *configFromEnv = utils::secure_getenv("LIBCAMERA_RPI_CONFIG_FILE");
+	if (!configFromEnv || *configFromEnv == '\0')
+		filename = configurationFile("raspberrypi/default.json");
+	else
+		filename = std::string(configFromEnv);
+
+	if (filename.empty())
+		return -EINVAL;
+
+	File file(filename);
+	if (!file.open(File::OpenModeFlag::ReadOnly)) {
+		LOG(RPI, Error) << "Failed to open configuration file '" << filename << "'";
+		return -EIO;
+	}
+
+	LOG(RPI, Info) << "Using configuration file '" << filename << "'";
+
+	std::unique_ptr<YamlObject> root = YamlParser::parse(file);
+	if (!root) {
+		LOG(RPI, Error) << "Failed to parse configuration file, using defaults!";
+		return -EINVAL;
+	}
+
+	ASSERT((*root)["version"].get<double>() == 1.0);
+
+	const YamlObject &phConfig = (*root)["pipeline_handler"];
+	config.minUnicamBuffers =
+		phConfig["min_unicam_buffers"].get<unsigned int>(config.minUnicamBuffers);
+	config.minTotalUnicamBuffers =
+		phConfig["min_total_unicam_buffers"].get<unsigned int>(config.minTotalUnicamBuffers);
+	config.numOutput0Buffers =
+		phConfig["num_output0_buffers"].get<unsigned int>(config.numOutput0Buffers);
+
+	if (config.minTotalUnicamBuffers < config.minUnicamBuffers || config.minTotalUnicamBuffers < 1) {
+		LOG(RPI, Error) << "Invalid Unicam buffer configuration used!";
+		return -EINVAL;
+	}
+
 	return 0;
 }
 
@@ -1471,6 +1526,7 @@  int PipelineHandlerRPi::prepareBuffers(Camera *camera)
 			 */
 			numBuffers = std::max<int>(data->config_.minUnicamBuffers,
 						   minBuffers - numRawBuffers);
+			data->numUnicamBuffers = numBuffers;
 		} else if (stream == &data->isp_[Isp::Input]) {
 			/*
 			 * ISP input buffers are imported from Unicam, so follow