Initial Pico/2 W Bazel support (#2049)

* Initial Pico 2 W Bazel support

Improves compatibility with Pico W and Pico 2 W by fixing issues that
prevented correct linking of wireless libraries.

* Improve correctness and configurability

* Require newer rules_python

* Require rules_python@0.36.0

* Fix missing compatibility expressions

* Minor tweaks

* Minor cleanup

* Update suggested version in Bazel README

* More README tweaks

* Improve Bazel btstack build correctness

MODULE.bazel

@@ -5,7 +5,7 @@ module(
 
 bazel_dep(name = "platforms", version = "0.0.9")
 bazel_dep(name = "bazel_skylib", version = "1.6.1")
-bazel_dep(name = "rules_python", version = "0.22.1")
+bazel_dep(name = "rules_python", version = "0.36.0")
 bazel_dep(name = "picotool", version = "2.0.0")
 bazel_dep(name = "rules_cc", version = "0.0.10")
 
@@ -132,3 +132,19 @@ register_toolchains(
     # Require users to opt-in to the Pico SDK's toolchains.
     dev_dependency = True,
 )
+
+python = use_extension("@rules_python//python/extensions:python.bzl", "python")
+python.toolchain(
+    configure_coverage_tool = True,
+    python_version = "3.9",
+)
+
+use_repo(python, "pythons_hub")
+register_toolchains(
+    "@pythons_hub//:all",
+    dev_dependency = True,
+)
+register_toolchains(
+    "@rules_python//python/runtime_env_toolchains:all",
+    dev_dependency = True,
+)

bazel/README.md

@@ -6,7 +6,7 @@
 First, in your `MODULE.bazel` file, add a dependency on the Pico SDK and
 `rules_cc`:
 ```python
-bazel_dep(name = "pico-sdk", version = "2.0.1")
+bazel_dep(name = "pico-sdk", version = "2.1.0")
 ```
 
 ### Register toolchains
@@ -92,11 +92,12 @@ you encounter along the way.
 
 Currently, the following features are not supported:
 
+* Pico W wireless libraries work, but may not have complete feature parity with
+  the CMake build.
+* Bazel does not yet provide RISC-V support for Pico 2/RP2350.
 * The pioasm parser cannot be built from source via Bazel.
 * Windows MSVC wildcard build (`bazel build //...`) does not work when targeting
   host.
-* Bazel does not yet provide RISC-V support for Pico 2/RP2350.
-* Pico W wireless libraries have link issues.
 
 ## Contributing
 When making changes to the Bazel build, please run the Bazel validation script

bazel/config/BUILD.bazel

@@ -151,6 +151,17 @@ string_flag(
     ],
 )
 
+# PICO_BAZEL_CONFIG: PICO_ASYNC_CONTEXT_IMPL, The default implementation for pico_async_context to link, type=string, default=threadsafe_background, group=build
+string_flag(
+    name = "PICO_ASYNC_CONTEXT_IMPL",
+    build_setting_default = "threadsafe_background",
+    values = [
+        "poll",
+        "threadsafe_background",
+        "freertos",
+    ],
+)
+
 # PICO_BAZEL_CONFIG: PICO_BINARY_INFO_ENABLED, Whether to include binary info in final firmware, type=bool, default=1, group=pico_stdlib
 bool_flag(
     name = "PICO_BINARY_INFO_ENABLED",
@@ -248,6 +259,24 @@ label_flag(
     build_setting_default = "//bazel:empty_cc_lib",
 )
 
+# PICO_BAZEL_CONFIG: PICO_BT_ENABLE_BLE, [Bazel only] Whether or not to link in BLE portions of the btstack as part of //src/rp2_common/pico_btstack. Also defines ENABLE_BLE=1, type=bool, default=False, group=wireless
+bool_flag(
+    name = "PICO_BT_ENABLE_BLE",
+    build_setting_default = False,
+)
+
+# PICO_BAZEL_CONFIG: PICO_BT_ENABLE_CLASSIC, [Bazel only] Whether or not to link in classic BT portions of the btstack as part of //src/rp2_common/pico_btstack. Also defines ENABLE_CLASSIC=1, type=bool, default=False, group=wireless
+bool_flag(
+    name = "PICO_BT_ENABLE_CLASSIC",
+    build_setting_default = False,
+)
+
+# PICO_BAZEL_CONFIG: PICO_BT_ENABLE_MESH, [Bazel only] Whether or not to link in mesh BT portions of the btstack as part of //src/rp2_common/pico_btstack. Also defines ENABLE_MESH=1, type=bool, default=False, group=wireless
+bool_flag(
+    name = "PICO_BT_ENABLE_MESH",
+    build_setting_default = False,
+)
+
 # PICO_BAZEL_CONFIG: PICO_LWIP_CONFIG, [Bazel only] The cc_library that provides lwipopts.h, default=//bazel:empty_cc_lib, group=wireless
 label_flag(
     name = "PICO_LWIP_CONFIG",

bazel/constraint/BUILD.bazel

@@ -1,3 +1,5 @@
+load("//bazel/util:label_flag_matches.bzl", "label_flag_matches")
+
 package(default_visibility = ["//visibility:public"])
 
 # This constraint represents the dimension that guides the Pico SDK build. This
@@ -48,6 +50,11 @@ config_setting(
     flag_values = {"//bazel/config:PICO_BOARD": "pico_w"},
 )
 
+config_setting(
+    name = "is_pico2_w",
+    flag_values = {"//bazel/config:PICO_BOARD": "pico2_w"},
+)
+
 config_setting(
     name = "pico_toolchain_clang_enabled",
     flag_values = {"//bazel/config:PICO_TOOLCHAIN": "clang"},
@@ -173,6 +180,21 @@ config_setting(
     flag_values = {"//bazel/config:PICO_DEFAULT_PRINTF_IMPL": "compiler"},
 )
 
+config_setting(
+    name = "pico_async_context_poll_enabled",
+    flag_values = {"//bazel/config:PICO_ASYNC_CONTEXT_IMPL": "poll"},
+)
+
+config_setting(
+    name = "pico_async_context_threadsafe_background_enabled",
+    flag_values = {"//bazel/config:PICO_ASYNC_CONTEXT_IMPL": "threadsafe_background"},
+)
+
+config_setting(
+    name = "pico_async_context_freertos_enabled",
+    flag_values = {"//bazel/config:PICO_ASYNC_CONTEXT_IMPL": "freertos"},
+)
+
 config_setting(
     name = "pico_use_default_max_page_size_enabled",
     flag_values = {"//bazel/config:PICO_USE_DEFAULT_MAX_PAGE_SIZE": "True"},
@@ -199,16 +221,34 @@ config_setting(
 )
 
 config_setting(
-    name = "pico_btstack_config_unset",
-    flag_values = {"//bazel/config:PICO_BTSTACK_CONFIG": "//bazel:empty_cc_lib"},
+    name = "pico_bt_enable_ble_enabled",
+    flag_values = {"//bazel/config:PICO_BT_ENABLE_BLE": "True"},
 )
 
 config_setting(
-    name = "pico_lwip_config_unset",
-    flag_values = {"//bazel/config:PICO_LWIP_CONFIG": "//bazel:empty_cc_lib"},
+    name = "pico_bt_enable_classic_enabled",
+    flag_values = {"//bazel/config:PICO_BT_ENABLE_CLASSIC": "True"},
 )
 
 config_setting(
+    name = "pico_bt_enable_mesh_enabled",
+    flag_values = {"//bazel/config:PICO_BT_ENABLE_MESH": "True"},
+)
+
+label_flag_matches(
+    name = "pico_lwip_config_unset",
+    flag = "//bazel/config:PICO_LWIP_CONFIG",
+    value = "//bazel:empty_cc_lib",
+)
+
+label_flag_matches(
+    name = "pico_btstack_config_unset",
+    flag = "//bazel/config:PICO_BTSTACK_CONFIG",
+    value = "//bazel:empty_cc_lib",
+)
+
+label_flag_matches(
     name = "pico_freertos_unset",
-    flag_values = {"//bazel/config:PICO_FREERTOS_LIB": "//bazel:empty_cc_lib"},
+    flag = "//bazel/config:PICO_FREERTOS_LIB",
+    value = "//bazel:empty_cc_lib",
 )

bazel/defs.bzl

@@ -88,6 +88,7 @@ def compatible_with_pico_w():
     return select({
         "@pico-sdk//bazel/constraint:cyw43_wireless": [],
         "@pico-sdk//bazel/constraint:is_pico_w": [],
+        "@pico-sdk//bazel/constraint:is_pico2_w": [],
         "//conditions:default": ["@platforms//:incompatible"],
     })
 

bazel/pico_btstack_make_gatt_header.bzl

@@ -0,0 +1,59 @@
+load("@rules_cc//cc:find_cc_toolchain.bzl", "find_cpp_toolchain", "use_cc_toolchain")
+
+def _pico_btstack_make_gatt_header_impl(ctx):
+    cc_toolchain = find_cpp_toolchain(ctx)
+    feature_configuration = cc_common.configure_features(
+        ctx = ctx,
+        cc_toolchain = cc_toolchain,
+        requested_features = ctx.features,
+        unsupported_features = ctx.disabled_features,
+    )
+
+    out = ctx.actions.declare_file(
+        "{}_gatt_generated/{}.h".format(ctx.label.name, ctx.file.src.basename.removesuffix(".gatt")),
+    )
+
+    ctx.actions.run(
+        executable = ctx.executable._make_gat_header_tool,
+        arguments = [
+            ctx.file.src.path,
+            out.path,
+            "-I",
+            ctx.file._btstack_hdr.dirname,
+        ] + [
+
+        ],
+        inputs = [
+            ctx.file.src,
+            ctx.file._btstack_hdr,
+        ],
+        outputs = [out],
+    )
+
+    cc_ctx = cc_common.create_compilation_context(
+        headers = depset(direct = [out]),
+        includes = depset(direct = [out.dirname]),
+    )
+
+    return [
+        DefaultInfo(files = depset(direct = [out])),
+        CcInfo(compilation_context = cc_ctx)
+    ]
+
+pico_btstack_make_gatt_header = rule(
+    implementation = _pico_btstack_make_gatt_header_impl,
+    attrs = {
+        "src": attr.label(mandatory = True, allow_single_file = True),
+        "_btstack_hdr": attr.label(
+            default = "@btstack//:src/bluetooth_gatt.h",
+            allow_single_file = True,
+        ),
+        "_make_gat_header_tool": attr.label(
+            default = "@btstack//:compile_gatt",
+            cfg = "exec",
+            executable = True,
+        ),
+    },
+    fragments = ["cpp"],
+    toolchains = use_cc_toolchain(),
+)

bazel/util/label_flag_matches.bzl

@@ -0,0 +1,37 @@
+"""A wrapper that enables a `config_setting` matcher for label_flag flags."""
+
+load("@bazel_skylib//rules:common_settings.bzl", "BuildSettingInfo")
+load("@bazel_tools//tools/cpp:toolchain_utils.bzl", "find_cpp_toolchain", "use_cpp_toolchain")
+
+def _match_label_flag_impl(ctx):
+    matches = str(ctx.attr.expected_value.label) == str(ctx.attr.flag.label)
+    return [
+        config_common.FeatureFlagInfo(value = str(matches)),
+        BuildSettingInfo(value = matches),
+    ]
+
+_match_label_flag = rule(
+    implementation = _match_label_flag_impl,
+    attrs = {
+        "expected_value": attr.label(
+            mandatory = True,
+            doc = "The expected flag value",
+        ),
+        "flag": attr.label(
+            mandatory = True,
+            doc = "The flag to extract a value from",
+        ),
+    },
+)
+
+def label_flag_matches(*, name, flag, value):
+    _match_label_flag(
+        name = name + "._impl",
+        expected_value = native.package_relative_label(value),
+        flag = flag,
+    )
+
+    native.config_setting(
+        name = name,
+        flag_values = {":{}".format(name + "._impl"): "True"},
+    )

bazel/util/transition.bzl

@@ -1,3 +1,9 @@
+def _normalize_flag_value(val):
+    """Converts flag values to transition-safe primitives."""
+    if type(val) == "label":
+        return str(val)
+    return val
+
 def declare_transtion(attrs, flag_overrides = None, append_to_flags = None, executable = True):
     """A helper that drastically simplifies declaration of a transition.
 
@@ -31,7 +37,7 @@ def declare_transtion(attrs, flag_overrides = None, append_to_flags = None, exec
         final_overrides = {}
         if flag_overrides != None:
             final_overrides = {
-                key: str(getattr(attrs, value))
+                key: _normalize_flag_value(getattr(attrs, value))
                 for key, value in flag_overrides.items()
             }
         if append_to_flags != None:
@@ -108,6 +114,8 @@ kitchen_sink_test_binary = declare_transtion(
     attrs = {
         "bt_stack_config": attr.label(mandatory = True),
         "lwip_config": attr.label(mandatory = True),
+        "enable_ble": attr.bool(default = False),
+        "enable_bt_classic": attr.bool(default = False),
         # This could be shared, but we don't in order to make it clearer that
         # a transition is in use.
         "_allowlist_function_transition": attr.label(
@@ -117,6 +125,8 @@ kitchen_sink_test_binary = declare_transtion(
     flag_overrides = {
         "@pico-sdk//bazel/config:PICO_BTSTACK_CONFIG": "bt_stack_config",
         "@pico-sdk//bazel/config:PICO_LWIP_CONFIG": "lwip_config",
+        "@pico-sdk//bazel/config:PICO_BT_ENABLE_BLE": "enable_ble",
+        "@pico-sdk//bazel/config:PICO_BT_ENABLE_CLASSIC": "enable_bt_classic",
     },
 )
 

src/rp2_common/pico_async_context/BUILD.bazel

@@ -2,8 +2,18 @@ load("//bazel:defs.bzl", "compatible_with_rp2", "incompatible_with_config")
 
 package(default_visibility = ["//visibility:public"])
 
-cc_library(
+alias(
     name = "pico_async_context",
+    actual = select({
+        "//bazel/constraint:pico_async_context_poll_enabled": ":pico_async_context_poll",
+        "//bazel/constraint:pico_async_context_threadsafe_background_enabled": ":pico_async_context_threadsafe_background",
+        "//bazel/constraint:pico_async_context_freertos_enabled": ":pico_async_context_freertos",
+        "//conditions:default": "//bazel:incompatible_cc_lib",
+    }),
+)
+
+cc_library(
+    name = "pico_async_context_base",
     srcs = ["async_context_base.c"],
     hdrs = [
         "include/pico/async_context.h",
@@ -26,7 +36,7 @@ cc_library(
         "//bazel/constraint:pico_freertos_unset",
     ),
     deps = [
-        ":pico_async_context",
+        ":pico_async_context_base",
         "//bazel/config:PICO_FREERTOS_LIB",
         "//src/common/pico_sync",
         "//src/common/pico_time",
@@ -42,7 +52,7 @@ cc_library(
     includes = ["include"],
     target_compatible_with = compatible_with_rp2(),
     deps = [
-        ":pico_async_context",
+        ":pico_async_context_base",
         "//src/common/pico_sync",
         "//src/common/pico_time",
         "//src/rp2_common:pico_platform",
@@ -56,7 +66,7 @@ cc_library(
     includes = ["include"],
     target_compatible_with = compatible_with_rp2(),
     deps = [
-        ":pico_async_context",
+        ":pico_async_context_base",
         "//src/common/pico_sync",
         "//src/common/pico_time",
         "//src/rp2_common:pico_platform",