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/* SPDX-License-Identifier: GPL-2.0-only */
/* This file is part of the coreboot project. */
#include <types.h>
#include <string.h>
#include <arch/cpu.h>
#include <cpu/x86/msr.h>
#include <console/console.h>
#include <cpu/intel/speedstep.h>
/**
* @brief Gather speedstep limits for current processor
*
* At least power limits are processor type specific. Penryn introduced half
* steps in bus ratios. Don't know about Atom processors.
*/
static void speedstep_get_limits(sst_params_t *const params)
{
msr_t msr;
const uint16_t cpu_id = (cpuid_eax(1) >> 4) & 0xffff;
const uint32_t state_mask =
/* Penryn supports non integer (i.e. half) ratios. */
((cpu_id == 0x1067) ? SPEEDSTEP_RATIO_NONINT : 0)
| SPEEDSTEP_RATIO_VALUE_MASK | SPEEDSTEP_VID_MASK;
/* Initialize params to zero. */
memset(params, '\0', sizeof(*params));
/* Read Super-LFM parameters. */
if (((rdmsr(MSR_EXTENDED_CONFIG).lo >> 27) & 3) == 3) {/*supported and
enabled bits */
msr = rdmsr(MSR_FSB_CLOCK_VCC);
params->slfm = SPEEDSTEP_STATE_FROM_MSR(msr.lo, state_mask);
params->slfm.dynfsb = 1;
params->slfm.is_slfm = 1;
}
/* Read normal minimum parameters. */
msr = rdmsr(MSR_THERM2_CTL);
params->min = SPEEDSTEP_STATE_FROM_MSR(msr.lo, state_mask);
/* Read normal maximum parameters. */
/* Newer CPUs provide the normal maximum settings in
IA32_PLATFORM_ID. The values in IA32_PERF_STATUS change
when using turbo mode. */
msr = rdmsr(IA32_PLATFORM_ID);
params->max = SPEEDSTEP_STATE_FROM_MSR(msr.lo, state_mask);
if (cpu_id == 0x006e) {
/* Looks like Yonah CPUs don't have the frequency ratio in
IA32_PLATFORM_ID. Use IA32_PERF_STATUS instead, the reading
should be reliable as those CPUs don't have turbo mode. */
msr = rdmsr(IA32_PERF_STATUS);
params->max.ratio = (msr.hi & SPEEDSTEP_RATIO_VALUE_MASK)
>> SPEEDSTEP_RATIO_SHIFT;
}
/* Read turbo parameters. */
msr = rdmsr(MSR_FSB_CLOCK_VCC);
if ((msr.hi & (1 << (63 - 32))) &&
/* supported and */
!(rdmsr(IA32_MISC_ENABLE).hi & (1 << (38 - 32)))) {
/* not disabled */
params->turbo = SPEEDSTEP_STATE_FROM_MSR(msr.hi, state_mask);
params->turbo.is_turbo = 1;
}
/* Set power limits by processor type. */
/* Defined values match the normal voltage versions only. But
they are only a hint for OSPM, so this should not hurt much. */
switch (cpu_id) {
case 0x006e:
/* Yonah */
params->min.power = SPEEDSTEP_MIN_POWER_YONAH;
params->max.power = SPEEDSTEP_MAX_POWER_YONAH;
break;
case 0x1067:
/* Penryn */
params->slfm.power = SPEEDSTEP_SLFM_POWER_PENRYN;
params->min.power = SPEEDSTEP_MIN_POWER_PENRYN;
params->max.power = SPEEDSTEP_MAX_POWER_PENRYN;
params->turbo.power = SPEEDSTEP_MAX_POWER_PENRYN;
break;
case 0x006f:
/* Merom */
default:
/* Use Merom values by default (as before). */
params->slfm.power = SPEEDSTEP_SLFM_POWER_MEROM;
params->min.power = SPEEDSTEP_MIN_POWER_MEROM;
params->max.power = SPEEDSTEP_MAX_POWER_MEROM;
params->turbo.power = SPEEDSTEP_MAX_POWER_MEROM;
break;
}
}
/**
* @brief Generate full p-states table from processor parameters
*
* This is generic code and should work at least for Merom and Penryn
* processors. It is used to generate ACPI tables and configure EMTTM.
*/
void speedstep_gen_pstates(sst_table_t *const table)
{
sst_params_t params;
/* Gather speedstep limits. */
speedstep_get_limits(¶ms);
/*\ First, find the number of normal states: \*/
/* Calculate with doubled values to work
around non-integer (.5) bus ratios. */
const int power_diff2 = (params.max.power - params.min.power) * 2;
const int vid_diff2 = (params.max.vid - params.min.vid) * 2;
const int max_ratio2 = SPEEDSTEP_DOUBLE_RATIO(params.max);
const int min_ratio2 = SPEEDSTEP_DOUBLE_RATIO(params.min);
const int ratio_diff2 = max_ratio2 - min_ratio2;
/* Calculate number of normal states (LFM to HFM, min to max). */
/* Increase step size, until all states fit into the table.
(Note: First try should always work, if
SPEEDSTEP_MAX_NORMAL_STATES is set correctly.) */
int states, step2 = 0;
do {
step2 += 2 * 2; /* Must be a multiple of 2 (doubled). */
states = ratio_diff2 / step2 + 1;
} while (states > SPEEDSTEP_MAX_NORMAL_STATES);
if (step2 > 4)
printk(BIOS_INFO, "Enhanced Speedstep processor with "
"more than %d possible p-states.\n",
SPEEDSTEP_MAX_NORMAL_STATES);
if (states < 2) /* Report at least two normal states. */
states = 2;
/*\ Now, fill the table: \*/
table->num_states = 0;
/* Add turbo state if supported. */
if (params.turbo.is_turbo)
table->states[table->num_states++] = params.turbo;
/* Add HFM first. */
table->states[table->num_states] = params.max;
/* Work around HFM and LFM having the same bus ratio. */
if ((params.max.dynfsb == params.min.dynfsb) &&
(params.max.nonint == params.min.nonint) &&
(params.max.ratio == params.min.ratio))
table->states[table->num_states].vid = params.min.vid;
++table->num_states;
--states;
/* Now, add all other normal states based on LFM (min). */
const int power_step = (power_diff2 / states) / 2;
const int vid_step = (vid_diff2 / states) / 2;
const int ratio_step = step2 / 2;
int power = params.min.power + (states - 1) * power_step;
int vid = params.min.vid + (states - 1) * vid_step;
int ratio = params.min.ratio + (states - 1) * ratio_step;
for (; states > 0; --states) {
table->states[table->num_states++] =
(sst_state_t){ 0, 0, ratio, vid, 0, 0, power };
power -= power_step;
vid -= vid_step;
ratio -= ratio_step;
}
/* At last, add Super-LFM state if supported. */
if (params.slfm.is_slfm)
table->states[table->num_states++] = params.slfm;
}
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