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| author | Nico Huber <nico.h@gmx.de> | 2012-11-05 21:46:33 +0100 |
|---|---|---|
| committer | Nico Huber <nico.h@gmx.de> | 2017-06-22 11:14:15 +0000 |
| commit | 8624e8cfa88ebd17ecf3bfd55c8dc1a799f47573 (patch) | |
| tree | f61a16e60f193b5e3f13a377a81d1308b1b4f0ad /Makefile | |
| parent | 2d62572d1dd0c37eb626fd8faa17b26690f20b15 (diff) | |
| download | flashrom-8624e8cfa88ebd17ecf3bfd55c8dc1a799f47573.tar.gz flashrom-8624e8cfa88ebd17ecf3bfd55c8dc1a799f47573.tar.bz2 flashrom-8624e8cfa88ebd17ecf3bfd55c8dc1a799f47573.zip | |
udelay: Use clock_gettime() if available and precise
Instead of calibrating our busy loop against a coarse clock, check if
a precise clock is available and loop against that. The former is unre-
liable by definition on any modern system that may dynamically reclock
the processor.
v2: Apparently _POSIX_MONOTONIC_CLOCK being defined only means that
the library knows about CLOCK_MONOTONIC. So check for its support
at runtime and fall back to CLOCK_REALTIME if it's missing.
TEST=Manually added a 10s loop and compared to real time. Run
on Linux RPi3, Linux x86 and my original use case Linux in
VirtualBox (Linux host).
Change-Id: I85ad359823875237ada9cd027af3017d62e9a235
Signed-off-by: Nico Huber <nico.h@gmx.de>
Reviewed-on: https://review.coreboot.org/19391
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: David Hendricks <david.hendricks@gmail.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Diffstat (limited to 'Makefile')
| -rw-r--r-- | Makefile | 22 |
1 files changed, 22 insertions, 0 deletions
@@ -1003,6 +1003,9 @@ FEATURE_CFLAGS += $(call debug_shell,grep -q "UTSNAME := yes" .features && print # We could use PULLED_IN_LIBS, but that would be ugly. FEATURE_LIBS += $(call debug_shell,grep -q "NEEDLIBZ := yes" .libdeps && printf "%s" "-lz") +FEATURE_CFLAGS += $(call debug_shell,grep -q "CLOCK_GETTIME := yes" .features && printf "%s" "-D'HAVE_CLOCK_GETTIME=1'") +FEATURE_LIBS += $(call debug_shell,grep -q "CLOCK_GETTIME := yes" .features && printf "%s" "-lrt") + LIBFLASHROM_OBJS = $(CHIP_OBJS) $(PROGRAMMER_OBJS) $(LIB_OBJS) OBJS = $(CLI_OBJS) $(LIBFLASHROM_OBJS) @@ -1299,6 +1302,18 @@ int main(int argc, char **argv) endef export LINUX_I2C_TEST +define CLOCK_GETTIME_TEST +#include <time.h> + +int main(int argc, char **argv) +{ + struct timespec res; + clock_gettime(CLOCK_REALTIME, &res); + return 0; +} +endef +export CLOCK_GETTIME_TEST + features: compiler @echo "FEATURES := yes" > .features.tmp ifneq ($(NEED_LIBFTDI), ) @@ -1341,6 +1356,13 @@ endif @ { $(CC) $(CPPFLAGS) $(CFLAGS) $(LDFLAGS) .featuretest.c -o .featuretest$(EXEC_SUFFIX) >&2 && \ ( echo "found."; echo "UTSNAME := yes" >> .features.tmp ) || \ ( echo "not found."; echo "UTSNAME := no" >> .features.tmp ) } 2>>$(BUILD_DETAILS_FILE) | tee -a $(BUILD_DETAILS_FILE) + @printf "Checking for clock_gettime support... " | tee -a $(BUILD_DETAILS_FILE) + @echo "$$CLOCK_GETTIME_TEST" >.featuretest.c + @printf "\nexec: %s\n" "$(CC) $(CPPFLAGS) $(CFLAGS) $(LDFLAGS) -lrt .featuretest.c -o .featuretest$(EXEC_SUFFIX)" >>$(BUILD_DETAILS_FILE) + @ { $(CC) $(CPPFLAGS) $(CFLAGS) $(LDFLAGS) -lrt .featuretest.c -o .featuretest$(EXEC_SUFFIX) >&2 && \ + ( echo "found."; echo "CLOCK_GETTIME := yes" >>.features.tmp ) || \ + ( echo "not found."; echo "CLOCK_GETTIME := no" >>.features.tmp ) } \ + 2>>$(BUILD_DETAILS_FILE) | tee -a $(BUILD_DETAILS_FILE) @$(DIFF) -q .features.tmp .features >/dev/null 2>&1 && rm .features.tmp || mv .features.tmp .features @rm -f .featuretest.c .featuretest$(EXEC_SUFFIX) |