[libcamera-devel] [PATCH] meson: Only build pipeline handlers needed in the host architecture

[Javier Martinez Canillas]

By default all pipeline handlers are built, regardless on whether these
are needed in the host architecture or not. It makes more sense to build
only the pipeline handlers that will be used for the given architecture.

Let's do that by default now, but still allow to build the other pipeline
handlers if needed, by using the `pipelines` meson option. For example:

  $ meson build
  ...
    Configuration
    Enabled pipelines        : ipu3
                               simple
                               uvcvideo
    Enabled IPA modules      : ipu3
  ...

  $ meson build -Dpipelines="ipu3,raspberrypi,rkisp1" -Dtest=true
  ...
    Configuration
    Enabled pipelines        : ipu3
                               raspberrypi
                               rkisp1
                               vimc
    Enabled IPA modules      : ipu3
                               raspberrypi
                               rkisp1
                               vimc
  ...

Suggested-by: Kieran Bingham <kieran.bingham at ideasonboard.com>
Signed-off-by: Javier Martinez Canillas <javierm at redhat.com>
---

 meson.build       | 14 ++++++++++++++
 meson_options.txt |  6 ++++--
 2 files changed, 18 insertions(+), 2 deletions(-)

diff --git a/meson.build b/meson.build
index d02f9917965c..fc1023326ed3 100644
--- a/meson.build
+++ b/meson.build
@@ -164,6 +164,20 @@ liblttng = dependency('lttng-ust', required : get_option('tracing'))
 # are enabled.
 pipelines = get_option('pipelines')
 
+if pipelines.contains('auto')
+    host_cpu = host_machine.cpu_family()
+    if host_cpu == 'x86' or host_cpu == 'x86_64'
+        pipelines = ['ipu3']
+    elif host_cpu == 'aarch64'
+        pipelines = ['imx8-isi', 'ipu3', 'raspberrypi', 'rkisp1']
+    elif host_cpu == 'arm'
+        pipelines = ['raspberrypi']
+    endif
+
+    # Always include the simple and uvcvideo pipeline handlers.
+    pipelines += ['simple', 'uvcvideo']
+endif
+
 if get_option('test') and 'vimc' not in pipelines
     message('Enabling vimc pipeline handler to support tests')
     pipelines += ['vimc']
diff --git a/meson_options.txt b/meson_options.txt
index 1ba6778ce257..23505805de41 100644
--- a/meson_options.txt
+++ b/meson_options.txt
@@ -37,8 +37,10 @@ option('lc-compliance',
 
 option('pipelines',
         type : 'array',
-        choices : ['imx8-isi', 'ipu3', 'raspberrypi', 'rkisp1', 'simple', 'uvcvideo', 'vimc'],
-        description : 'Select which pipeline handlers to include')
+        value : ['auto'],
+        choices : ['auto', 'imx8-isi', 'ipu3', 'raspberrypi', 'rkisp1', 'simple', 'uvcvideo', 'vimc'],
+        description : '''Select which pipeline handlers to build. If this is set to auto, all
+                       the pipelines applicable to the target architecture will be built.''')
 
 option('qcam',
         type : 'feature',
-- 
2.38.1