From: Simon Glass Date: Sat, 7 Dec 2019 04:41:50 +0000 (-0700) Subject: x86: timer: Reduce timer code size in TPL on Intel CPUs X-Git-Tag: v2020.04-rc1~39^2~2^2~85 X-Git-Url: https://git.librecmc.org/?a=commitdiff_plain;h=642e8487ec629b43b1c5caf846098bfc952be5c0;p=oweals%2Fu-boot.git x86: timer: Reduce timer code size in TPL on Intel CPUs 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 Reviewed-by: Bin Meng --- 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;