145 lines
3.5 KiB
C
145 lines
3.5 KiB
C
/*
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* This file is part of the coreboot project.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; version 2 of the License.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*/
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#include <stdint.h>
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#include <console/console.h>
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#include <delay.h>
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#include <thread.h>
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#include <arch/cpu.h>
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#include <arch/early_variables.h>
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#include <cpu/intel/fsb.h>
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#include <cpu/x86/msr.h>
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#include <cpu/x86/lapic.h>
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#include <cpu/intel/speedstep.h>
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/* NOTE: This code uses global variables, so it can not be used during
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* memory init.
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*/
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#if CONFIG_UDELAY_LAPIC_FIXED_FSB != 0
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static inline u32 get_timer_fsb(void)
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{
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return CONFIG_UDELAY_LAPIC_FIXED_FSB;
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}
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static int set_timer_fsb(void)
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{
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return 0;
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}
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#else
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static u32 g_timer_fsb CAR_GLOBAL;
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static int set_timer_fsb(void)
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{
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int ia32_fsb = get_ia32_fsb();
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if (ia32_fsb > 0) {
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car_set_var(g_timer_fsb, ia32_fsb);
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return 0;
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}
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return -1;
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}
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static inline u32 get_timer_fsb(void)
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{
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return car_get_var(g_timer_fsb);
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}
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#endif
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void init_timer(void)
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{
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/* Set the APIC timer to no interrupts and periodic mode */
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lapic_write(LAPIC_LVTT, (LAPIC_LVT_TIMER_PERIODIC | LAPIC_LVT_MASKED));
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/* Set the divider to 1, no divider */
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lapic_write(LAPIC_TDCR, LAPIC_TDR_DIV_1);
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/* Set the initial counter to 0xffffffff */
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lapic_write(LAPIC_TMICT, 0xffffffff);
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/* Set FSB frequency to a reasonable value */
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set_timer_fsb();
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}
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void udelay(u32 usecs)
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{
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u32 start, value, ticks, timer_fsb;
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if (!thread_yield_microseconds(usecs))
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return;
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timer_fsb = get_timer_fsb();
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if (!timer_fsb || (lapic_read(LAPIC_LVTT) &
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(LAPIC_LVT_TIMER_PERIODIC | LAPIC_LVT_MASKED)) !=
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(LAPIC_LVT_TIMER_PERIODIC | LAPIC_LVT_MASKED)) {
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init_timer();
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timer_fsb = get_timer_fsb();
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}
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/* Calculate the number of ticks to run, our FSB runs at timer_fsb Mhz
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*/
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ticks = usecs * timer_fsb;
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start = lapic_read(LAPIC_TMCCT);
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do {
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value = lapic_read(LAPIC_TMCCT);
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} while ((start - value) < ticks);
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}
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#if CONFIG(LAPIC_MONOTONIC_TIMER)
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#include <timer.h>
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static struct monotonic_counter {
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int initialized;
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struct mono_time time;
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uint32_t last_value;
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} mono_counter_g CAR_GLOBAL;
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void timer_monotonic_get(struct mono_time *mt)
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{
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uint32_t current_tick;
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uint32_t usecs_elapsed;
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uint32_t timer_fsb;
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struct monotonic_counter *mono_counter;
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mono_counter = car_get_var_ptr(&mono_counter_g);
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if (!mono_counter->initialized) {
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init_timer();
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timer_fsb = get_timer_fsb();
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/* An FSB frequency of 200Mhz provides a 20 second polling
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* interval between timer_monotonic_get() calls before wrap
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* around occurs. */
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if (timer_fsb > 200)
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printk(BIOS_WARNING,
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"apic timer freq (%d) may be too fast.\n",
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timer_fsb);
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mono_counter->last_value = lapic_read(LAPIC_TMCCT);
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mono_counter->initialized = 1;
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}
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timer_fsb = get_timer_fsb();
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current_tick = lapic_read(LAPIC_TMCCT);
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/* Note that the APIC timer counts down. */
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usecs_elapsed = (mono_counter->last_value - current_tick) / timer_fsb;
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/* Update current time and tick values only if a full tick occurred. */
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if (usecs_elapsed) {
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mono_time_add_usecs(&mono_counter->time, usecs_elapsed);
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mono_counter->last_value = current_tick;
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}
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/* Save result. */
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*mt = mono_counter->time;
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}
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#endif
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