Most of the timer-calibration methods are not needed on recent Intel CPUs and just increase code size. Add an option to use the known-good way to get the clock frequency in TPL. Size reduction is about 700 bytes.
Note that version 1 of this commit caused bootstage to crash since the CPU was not identified. This is corrected by changes previously applied to make sure that the CPU is identified before spl_init() is called, such as
39146a2e0b x86: Move CPU init to before spl_init()
Signed-off-by: Simon Glass sjg@chromium.org Reviewed-by: Bin Meng bmeng.cn@gmail.com ---
Changes in v6: None Changes in v5: None Changes in v4: - Update commit message to indicate that CPU-identity bug is fixed
Changes in v3: None Changes in v2: None
drivers/timer/Kconfig | 9 +++++++++ drivers/timer/tsc_timer.c | 7 +++++-- 2 files changed, 14 insertions(+), 2 deletions(-)
diff --git a/drivers/timer/Kconfig b/drivers/timer/Kconfig index 41f9755133..96cc49273f 100644 --- a/drivers/timer/Kconfig +++ b/drivers/timer/Kconfig @@ -188,6 +188,15 @@ config X86_TSC_READ_BASE The only exception is when U-Boot is used as a secondary bootloader, where this option should be enabled.
+config TPL_X86_TSC_TIMER_NATIVE + bool "x86 TSC timer uses native calibration" + depends on TPL && X86_TSC_TIMER + help + Selects native timer calibration for TPL and don't include the other + methods in the code. This helps to reduce code size in TPL and works + on fairly modern Intel chips. Code-size reductions is about 700 + bytes. + config MTK_TIMER bool "MediaTek timer support" depends on TIMER diff --git a/drivers/timer/tsc_timer.c b/drivers/timer/tsc_timer.c index 813817f467..43cb2d820e 100644 --- a/drivers/timer/tsc_timer.c +++ b/drivers/timer/tsc_timer.c @@ -50,8 +50,7 @@ static unsigned long native_calibrate_tsc(void) return 0;
crystal_freq = tsc_info.ecx / 1000; - - if (!crystal_freq) { + if (!CONFIG_IS_ENABLED(X86_TSC_TIMER_NATIVE) && !crystal_freq) { switch (gd->arch.x86_model) { case INTEL_FAM6_SKYLAKE_MOBILE: case INTEL_FAM6_SKYLAKE_DESKTOP: @@ -407,6 +406,10 @@ static void tsc_timer_ensure_setup(bool early) if (fast_calibrate) goto done;
+ /* Reduce code size by dropping other methods */ + if (CONFIG_IS_ENABLED(X86_TSC_TIMER_NATIVE)) + panic("no timer"); + fast_calibrate = cpu_mhz_from_cpuid(); if (fast_calibrate) goto done;