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Device tree changes for camera support on cronos

These changes are applied for you by 0011-device-tree-camera-enablement.patch (except section 3, the blob list, which docs/INSTALL.md step 6 covers, and section 4, sepolicy). This file explains why each one is needed - follow docs/INSTALL.md to actually install.

Three separate problems have to be fixed together. Applying only some of them leaves the camera enumerating zero devices exactly as it does today.

1. The declared camera provider does not exist

device/amazon/mt8163-common/manifest.xml currently declares:

<hal format="hidl">
    <name>android.hardware.camera.provider</name>
    <transport>hwbinder</transport>
    <fqname>@2.4::ICameraProvider/internal/0</fqname>
</hal>

internal/0 over hwbinder is MediaTek's own provider, served by the camerahalserver binary. That binary exists in the karnak (Fire HD 8 2018) blob set but Amazon never shipped it on the Echo Show devices, and nothing in this ROM provides it. The camera service looks the provider up, finds nothing, and reports no cameras, which is the behaviour observed on device.

The stock Echo Show blobs are a legacy camera1 HAL module (camera.mt8163.so), so the matching provider is AOSP's passthrough legacy one:

<hal format="hidl">
    <name>android.hardware.camera.provider</name>
    <transport arch="32+64">passthrough</transport>
    <version>2.4</version>
    <interface>
        <name>ICameraProvider</name>
        <instance>legacy/0</instance>
    </interface>
</hal>

2. The provider implementation is never built

device/amazon/mt8163-common/mt8163.mk builds the two device shims but no provider:

# Camera
PRODUCT_PACKAGES += \
    camera.device@1.0-impl \
    camera.device@3.2-impl \
    libsensorndkbridge

It needs the passthrough provider and the shim:

# Camera
PRODUCT_PACKAGES += \
    android.hardware.camera.provider@2.4-impl \
    camera.device@1.0-impl \
    camera.device@3.2-impl \
    libcamera_shim \
    libsensorndkbridge

android.hardware.camera.provider@2.4-impl pulls in android.hardware.camera.provider@2.4-legacy (LegacyCameraProviderImpl_2_4.cpp), which is what loads camera.mt8163.so through libhardware.

Add to device/amazon/<device>/BoardConfig.mk:

# Camera
TARGET_NEEDS_LEGACY_CAMERA_HAL1_DYN_NATIVE_HANDLE := true

3. The blobs are not extracted

The stock camera stack is absent from vendor/amazon/<device>. Append the contents of camera-proprietary-files.txt to device/amazon/<device>/proprietary-files.txt, then re-run extract-files.sh against a stock image (see scripts/fetch-camera-blobs.sh). The paths in that list are the same on all three devices; the blobs behind them are not, and must come from the device's own firmware (see scripts/device-config.sh).

45 libraries are required: the 34 libcam*/libmtkcam* libraries plus 11 transitive MediaTek dependencies (lib3a, libfeatureio, libfeatureiodrv, libhal_effects, libhdrproc, libimageio*, libmtk_mmutils, libmtkjpeg). Everything else the blobs need is already present on the device.

Note the stock layout is pre-Treble: the blobs live in /system/vendor/lib and name /system/bin/linker as their interpreter. The list rewrites them into /vendor/lib; camera.mt8163.so goes to /vendor/lib/hw/.

4. sepolicy

cameraserver needs access to the MediaTek camera nodes, which are already present on the device (/dev/camera-isp, /dev/camera-pipemgr, /dev/camera-sysram, /dev/kd_camera_hw, /dev/kd_camera_hw_bus2). Expect to label those and grant cameraserver and the passthrough provider access to them, plus the usual ion / m4u permissions. Start with permissive logging to collect the denials rather than guessing the rules.