From: Tomas Glozar <tglozar@xxxxxxxxxx>
Add test to detect the presence of libcpupower on the system, allowing
to conditionally build features that depend on it.
The test uses a similar mechanism to the Linux kernel's tools' feature
detection: a small C program using the library is compiled, and based on
the success of the compilation, the presence of the library is
determined.
Signed-off-by: Tomas Glozar <tglozar@xxxxxxxxxx>
---
Makefile | 11 +++++++++++
feature/Makefile | 12 ++++++++++++
feature/test-feature.mak | 4 ++++
feature/test-libcpupower.c | 8 ++++++++
4 files changed, 35 insertions(+)
create mode 100644 feature/Makefile
create mode 100644 feature/test-feature.mak
create mode 100644 feature/test-libcpupower.c
diff --git a/Makefile b/Makefile
index e2f8579..1f698cf 100644
--- a/Makefile
+++ b/Makefile
@@ -1,4 +1,6 @@
# SPDX-License-Identifier: GPL-2.0-or-later
+include feature/test-feature.mak
+
VERSION = 2.7
CC = $(CROSS_COMPILE)gcc
AR = $(CROSS_COMPILE)ar
@@ -37,6 +39,15 @@ LDFLAGS ?=
PYLIB ?= $(shell python3 -m get_pylib)
+# Check for optional libcpupower dependency
+ifeq ($(call test-feature,libcpupower), 0)
+CPPFLAGS += -DHAVE_LIBCPUPOWER_SUPPORT
+LDFLAGS += -lcpupower
+else
+$(warning libcpupower is missing, building without --deepest-idle-state support.)
+$(warning Please install libcpupower-dev/kernel-tools-libs-devel)
+endif
+
# Check for errors, such as python3 not available
ifeq (${PYLIB},)
undefine PYLIB
diff --git a/feature/Makefile b/feature/Makefile
new file mode 100644
index 0000000..085e3a9
--- /dev/null
+++ b/feature/Makefile
@@ -0,0 +1,12 @@
+# SPDX-License-Identifier: GPL-2.0-or-later
+all: feature-libcpupower
+
+feature-libcpupower: $(OBJDIR)/test-libcpupower.o
+
+$(OBJDIR)/test-libcpupower.o: feature/test-libcpupower.c
+ @$(CC) $(CFLAGS) $(CPPFLAGS) $< -lcpupower -o $@
+
+.PHONY: clean
+
+clean:
+ rm -f $(OBJDIR)/test-*.o
diff --git a/feature/test-feature.mak b/feature/test-feature.mak
new file mode 100644
index 0000000..fffddef
--- /dev/null
+++ b/feature/test-feature.mak
@@ -0,0 +1,4 @@
+# SPDX-License-Identifier: GPL-2.0-or-later
+define test-feature
+$(shell $(MAKE) OBJDIR=$(OBJDIR) -f feature/Makefile feature-$1 clean >/dev/null 2>/dev/null; echo $$?)
+endef
diff --git a/feature/test-libcpupower.c b/feature/test-libcpupower.c
new file mode 100644
index 0000000..cd16269
--- /dev/null
+++ b/feature/test-libcpupower.c
@@ -0,0 +1,8 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+#include <cpuidle.h>
+
+int main(void)
+{
+ int rv = cpuidle_state_count(0);
+ return rv;
+}
--
2.47.0
