From 152e5a03a130cea3009685cbf7eb0ea354d9fd1c Mon Sep 17 00:00:00 2001 From: Aaron Durbin Date: Wed, 10 Feb 2016 11:01:49 -0600 Subject: libpayload: honor TSC information under CONFIG_LP_TIMER_RDTSC When CONFIG_LP_TIMER_RDTSC is enabled honor the TSC information exported in the coreboot tables as the cpu_khz frequency. That allows get_cpu_speed() not to be called which currently relies on the 8254 PIT. As certain x86 platforms allow that device to be optional or turned off for power saving reasons, allow a path where get_cpu_speed() is no longer called. Additionally, this approach also allows the libpayload to not duplicate logic that already exists in coreboot. BUG=chrome-os-partner:50214 BRANCH=glados TEST=Confirmed in payload TSC frequency is honored instead of using get_cpu_speed(). Change-Id: Ib8993afdfb49065d43de705d6dbbdb9174b6f2c4 Signed-off-by: Aaron Durbin Reviewed-on: https://review.coreboot.org/13671 Tested-by: build bot (Jenkins) Reviewed-by: Martin Roth Reviewed-by: Andrey Petrov --- payloads/libpayload/arch/x86/sysinfo.c | 11 +++++++---- 1 file changed, 7 insertions(+), 4 deletions(-) (limited to 'payloads/libpayload/arch/x86') diff --git a/payloads/libpayload/arch/x86/sysinfo.c b/payloads/libpayload/arch/x86/sysinfo.c index c3336b81e4..ddd6550e08 100644 --- a/payloads/libpayload/arch/x86/sysinfo.c +++ b/payloads/libpayload/arch/x86/sysinfo.c @@ -32,12 +32,14 @@ #include #include +#define CPU_KHZ_DEFAULT 200 + /** * This is a global structure that is used through the library - we set it * up initially with some dummy values - hopefully they will be overridden. */ struct sysinfo_t lib_sysinfo = { - .cpu_khz = 200, + .cpu_khz = CPU_KHZ_DEFAULT, #if IS_ENABLED(CONFIG_LP_SERIAL_CONSOLE) .ser_ioport = CONFIG_LP_SERIAL_IOBASE, #else @@ -49,9 +51,6 @@ int lib_get_sysinfo(void) { int ret; - /* Get the CPU speed (for delays). */ - lib_sysinfo.cpu_khz = get_cpu_speed(); - #if IS_ENABLED(CONFIG_LP_MULTIBOOT) /* Get the information from the multiboot tables, * if they exist */ @@ -63,6 +62,10 @@ int lib_get_sysinfo(void) ret = get_coreboot_info(&lib_sysinfo); + /* Get the CPU speed (for delays) if not set from the default value. */ + if (lib_sysinfo.cpu_khz == CPU_KHZ_DEFAULT) + lib_sysinfo.cpu_khz = get_cpu_speed(); + if (!lib_sysinfo.n_memranges) { /* If we can't get a good memory range, use the default. */ lib_sysinfo.n_memranges = 2; -- cgit v1.2.3