163 lines
4.2 KiB
C
163 lines
4.2 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* acpi_lpit.c - LPIT table processing functions
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*
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* Copyright (C) 2017 Intel Corporation. All rights reserved.
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*/
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#include <linux/cpu.h>
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#include <linux/acpi.h>
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#include <asm/msr.h>
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#include <asm/tsc.h>
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#include "internal.h"
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struct lpit_residency_info {
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struct acpi_generic_address gaddr;
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u64 frequency;
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void __iomem *iomem_addr;
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};
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/* Storage for an memory mapped and FFH based entries */
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static struct lpit_residency_info residency_info_mem;
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static struct lpit_residency_info residency_info_ffh;
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static int lpit_read_residency_counter_us(u64 *counter, bool io_mem)
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{
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int err;
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if (io_mem) {
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u64 count = 0;
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int error;
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error = acpi_os_read_iomem(residency_info_mem.iomem_addr, &count,
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residency_info_mem.gaddr.bit_width);
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if (error)
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return error;
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*counter = div64_u64(count * 1000000ULL, residency_info_mem.frequency);
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return 0;
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}
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err = rdmsrl_safe(residency_info_ffh.gaddr.address, counter);
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if (!err) {
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u64 mask = GENMASK_ULL(residency_info_ffh.gaddr.bit_offset +
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residency_info_ffh.gaddr. bit_width - 1,
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residency_info_ffh.gaddr.bit_offset);
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*counter &= mask;
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*counter >>= residency_info_ffh.gaddr.bit_offset;
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*counter = div64_u64(*counter * 1000000ULL, residency_info_ffh.frequency);
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return 0;
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}
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return -ENODATA;
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}
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static ssize_t low_power_idle_system_residency_us_show(struct device *dev,
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struct device_attribute *attr,
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char *buf)
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{
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u64 counter;
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int ret;
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ret = lpit_read_residency_counter_us(&counter, true);
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if (ret)
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return ret;
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return sprintf(buf, "%llu\n", counter);
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}
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static DEVICE_ATTR_RO(low_power_idle_system_residency_us);
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static ssize_t low_power_idle_cpu_residency_us_show(struct device *dev,
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struct device_attribute *attr,
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char *buf)
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{
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u64 counter;
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int ret;
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ret = lpit_read_residency_counter_us(&counter, false);
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if (ret)
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return ret;
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return sprintf(buf, "%llu\n", counter);
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}
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static DEVICE_ATTR_RO(low_power_idle_cpu_residency_us);
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int lpit_read_residency_count_address(u64 *address)
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{
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if (!residency_info_mem.gaddr.address)
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return -EINVAL;
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*address = residency_info_mem.gaddr.address;
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return 0;
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}
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EXPORT_SYMBOL_GPL(lpit_read_residency_count_address);
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static void lpit_update_residency(struct lpit_residency_info *info,
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struct acpi_lpit_native *lpit_native)
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{
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struct device *dev_root = bus_get_dev_root(&cpu_subsys);
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/* Silently fail, if cpuidle attribute group is not present */
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if (!dev_root)
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return;
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info->frequency = lpit_native->counter_frequency ?
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lpit_native->counter_frequency : mul_u32_u32(tsc_khz, 1000U);
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if (!info->frequency)
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info->frequency = 1;
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info->gaddr = lpit_native->residency_counter;
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if (info->gaddr.space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY) {
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info->iomem_addr = ioremap(info->gaddr.address,
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info->gaddr.bit_width / 8);
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if (!info->iomem_addr)
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goto exit;
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sysfs_add_file_to_group(&dev_root->kobj,
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&dev_attr_low_power_idle_system_residency_us.attr,
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"cpuidle");
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} else if (info->gaddr.space_id == ACPI_ADR_SPACE_FIXED_HARDWARE) {
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sysfs_add_file_to_group(&dev_root->kobj,
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&dev_attr_low_power_idle_cpu_residency_us.attr,
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"cpuidle");
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}
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exit:
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put_device(dev_root);
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}
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static void lpit_process(u64 begin, u64 end)
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{
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while (begin + sizeof(struct acpi_lpit_native) <= end) {
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struct acpi_lpit_native *lpit_native = (struct acpi_lpit_native *)begin;
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if (!lpit_native->header.type && !lpit_native->header.flags) {
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if (lpit_native->residency_counter.space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY &&
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!residency_info_mem.gaddr.address) {
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lpit_update_residency(&residency_info_mem, lpit_native);
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} else if (lpit_native->residency_counter.space_id == ACPI_ADR_SPACE_FIXED_HARDWARE &&
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!residency_info_ffh.gaddr.address) {
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lpit_update_residency(&residency_info_ffh, lpit_native);
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}
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}
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begin += lpit_native->header.length;
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}
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}
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void acpi_init_lpit(void)
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{
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acpi_status status;
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struct acpi_table_lpit *lpit;
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status = acpi_get_table(ACPI_SIG_LPIT, 0, (struct acpi_table_header **)&lpit);
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if (ACPI_FAILURE(status))
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return;
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lpit_process((u64)lpit + sizeof(*lpit),
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(u64)lpit + lpit->header.length);
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acpi_put_table((struct acpi_table_header *)lpit);
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}
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