android: mm: generic: use GRALLOC_HARDWARE_MODULE_ID

PlatformFrameBufferAllocator is an abstraction over gralloc.
Right now hardwareModule_ points towards a CAMERA_HARDWARE_MODULE_ID.

When gralloc_open() is called we observe:
libcamera: DEBUG HAL camera3_hal.cpp:75 Open camera gpu0
libcamera: ERROR Camera camera.cpp:524 Camera in Configured state trying acquire() requiring state Available
01-23 14:14:04.742   370   416 E libcamera: FATAL HAL generic_frame_buffer_allocator.cpp:105 gralloc_open() failed: -87

Which is wrong, gralloc_open() is attempting to re-open the camera HAL,
instead of the gralloc HAL.

Point to a GRALLOC_HARDWARE_MODULE_ID instead so that we can request
buffers from gralloc in android.

Note: this adds new dependencies on android's libhardware [1] and on libdl.

[1] https://android.googlesource.com/platform/hardware/libhardware

Fixes: c58662c577 ("android: Introduce PlatformFrameBufferAllocator")
Signed-off-by: Mattijs Korpershoek <mkorpershoek@baylibre.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

src/android/mm/generic_frame_buffer_allocator.cpp

@@ -5,6 +5,7 @@
  * generic_camera_buffer.cpp - Allocate FrameBuffer using gralloc API
  */
 
+#include <dlfcn.h>
 #include <memory>
 #include <vector>
 
@@ -72,9 +73,10 @@ class PlatformFrameBufferAllocator::Private : public Extensible::Private
 public:
 	Private(CameraDevice *const cameraDevice)
 		: cameraDevice_(cameraDevice),
-		  hardwareModule_(cameraDevice->camera3Device()->common.module),
+		  hardwareModule_(nullptr),
 		  allocDevice_(nullptr)
 	{
+		hw_get_module(GRALLOC_HARDWARE_MODULE_ID, &hardwareModule_);
 		ASSERT(hardwareModule_);
 	}
 
@@ -85,7 +87,7 @@ public:
 
 private:
 	const CameraDevice *const cameraDevice_;
-	struct hw_module_t *const hardwareModule_;
+	const struct hw_module_t *hardwareModule_;
 	struct alloc_device_t *allocDevice_;
 };
 
@@ -93,6 +95,7 @@ PlatformFrameBufferAllocator::Private::~Private()
 {
 	if (allocDevice_)
 		gralloc_close(allocDevice_);
+	dlclose(hardwareModule_->dso);
 }
 
 std::unique_ptr<HALFrameBuffer>

src/android/mm/meson.build

@@ -4,6 +4,10 @@ platform = get_option('android_platform')
 if platform == 'generic'
     android_hal_sources += files(['generic_camera_buffer.cpp',
                                   'generic_frame_buffer_allocator.cpp'])
+    android_deps += [
+        libdl,
+        dependency('libhardware'),
+    ]
 elif platform == 'cros'
     android_hal_sources += files(['cros_camera_buffer.cpp',
                                   'cros_frame_buffer_allocator.cpp'])