From 6ac788cec84082d5fab0b25c2d8f5594d1ce502a Mon Sep 17 00:00:00 2001
From: Wyatt Hepler <hepler@google.com>
Date: Tue, 24 May 2022 14:16:08 -0700
Subject: [PATCH] pw_rpc: Provide option for disabling the mutex

- Provide a config that disable the global mutex for pw_rpc to simplify
  changing that setting from GN.
- Remove uses of pw_rpc:use_global_mutex since the global mutex is
  enabled by default now.

Change-Id: I80f8db797b8fc1141d85a8970425e22b6aa6a06e
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/95844
Pigweed-Auto-Submit: Wyatt Hepler <hepler@google.com>
Commit-Queue: Auto-Submit <auto-submit@pigweed.google.com.iam.gserviceaccount.com>
Reviewed-by: Rob Mohr <mohrr@google.com>
---
 pw_rpc/BUILD.gn                    | 15 +++++++++++++--
 pw_system/system_target.gni        |  2 --
 targets/host/target_toolchains.gni |  1 -
 3 files changed, 13 insertions(+), 5 deletions(-)

diff --git a/pw_rpc/BUILD.gn b/pw_rpc/BUILD.gn
index 4b8a7b35b2..3be85573d7 100644
--- a/pw_rpc/BUILD.gn
+++ b/pw_rpc/BUILD.gn
@@ -31,13 +31,24 @@ config("public_include_path") {
   visibility = [ ":*" ]
 }
 
+config("disable_global_mutex_config") {
+  defines = [ "PW_RPC_USE_GLOBAL_MUTEX=0" ]
+  visibility = [ ":*" ]
+}
+
+# Set pw_rpc_CONFIG to this to disable the global mutex. If additional options
+# are needed, a config target that sets those can depend on this.
+group("disable_global_mutex") {
+  public_configs = [ ":disable_global_mutex_config" ]
+}
+
 config("global_mutex_config") {
   defines = [ "PW_RPC_USE_GLOBAL_MUTEX=1" ]
   visibility = [ ":*" ]
 }
 
-# Set pw_rpc_CONFIG to this to enable the global mutex. If additional options
-# are needed, a config target that sets those can depend on this.
+# Set pw_rpc_CONFIG to this to always enable the global mutex. The mutex is
+# enabled by default, so this is a no-op.
 group("use_global_mutex") {
   public_configs = [ ":global_mutex_config" ]
 }
diff --git a/pw_system/system_target.gni b/pw_system/system_target.gni
index 8fe9d431de..ecef0bd0ca 100644
--- a/pw_system/system_target.gni
+++ b/pw_system/system_target.gni
@@ -106,8 +106,6 @@ template("pw_system_target") {
     # is added.
     pw_log_BACKEND = dir_pw_log_basic
 
-    pw_rpc_CONFIG = "$dir_pw_rpc:use_global_mutex"
-
     # TODO(amontanez): This should be set to a "$dir_pw_unit_test:rpc_main"
     # when RPC is working.
     pw_unit_test_MAIN = "$dir_pw_unit_test:logging_main"
diff --git a/targets/host/target_toolchains.gni b/targets/host/target_toolchains.gni
index 15c08acb49..2a79974de6 100644
--- a/targets/host/target_toolchains.gni
+++ b/targets/host/target_toolchains.gni
@@ -55,7 +55,6 @@ _host_common = {
 
   # Configure backend for pw_rpc_system_server.
   pw_rpc_system_server_BACKEND = "$dir_pigweed/targets/host:system_rpc_server"
-  pw_rpc_CONFIG = "$dir_pw_rpc:use_global_mutex"
 
   # Configure backend for trace facade.
   pw_trace_BACKEND = "$dir_pw_trace_tokenized"