commit 0e3733b80f795cbb095402c8b0cd61e0b4457503
author Faraaz Sareshwala <fsareshwala@google.com> Mon Mar 17 11:20:43 2025 -0700
committer CQ Bot Account <pigweed-scoped@luci-project-accounts.iam.gserviceaccount.com> Mon Mar 17 11:20:43 2025 -0700
tree bce5a8ec5ba7b3d543261b216ff4ba6cd5daa9d5
parent 40459ab8b2ebacd450aa9334c1dd9127cb3aad19

pw_bluetooth_sapphire: Support Controller packet filter offloading

This change updates Sapphire to support offloading packet filters to the
Controller when possible.

Until recently, Sapphire was targeted towards smart displays (e.g. when
providing the Bluetooth stack within Fuchsia). As Sapphire moves towards
support for embedded devices, power efficiency will become a much larger
focus. In this case, we want Sapphire to use the device’s battery as
efficiently as possible. One of the ways to achieve this is to offload
as much processing to the Controller’s processor as possible. This
allows the Host’s processor to remain idle or sleep for longer periods
of time, reducing power consumption in the Host.

The Sapphire stack currently implements Host level advertising packet
filtering. The Bluetooth Core Specification includes support for
chip-level advertising packet filters
(e.g. HCI_LE_Add_Device_To_Filter_Accept_List). However, the Core
Specification’s feature set isn’t as feature rich as the one we would
like to provide in Sapphire: it includes filtering only on device
addresses. Within Sapphire, we currently support filtering based on a
variety of other properties (e.g. service UUIDs, device name, etc).
However, these are Host level filters. For better power efficiency, we
want to offload this more feature-rich filtering onto the Controller
itself via Android vendor extensions. This change implements such
Controller based offloaded packet filtering.

Fixed: 42174576
Test: bazelisk test --config googletest //pw_bluetooth_sapphire/...
Change-Id: I42413bb35888d0615446d5fb835a6f0350842b1a
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/265639
Docs-Not-Needed: Faraaz Sareshwala <fsareshwala@google.com>
Commit-Queue: Faraaz Sareshwala <fsareshwala@google.com>
Reviewed-by: Jason Graffius <jgraff@google.com>
Lint: Lint 🤖 <android-build-ayeaye@system.gserviceaccount.com>