LXR linux/drivers/acpi/acpi

   1
   2/*
   3 * acpi_lpit.c - LPIT table processing functions
   4 *
   5 * Copyright (C) 2017 Intel Corporation. All rights reserved.
   6 *
   7 * This program is free software; you can redistribute it and/or
   8 * modify it under the terms of the GNU General Public License version
   9 * 2 as published by the Free Software Foundation.
  10 *
  11 * This program is distributed in the hope that it will be useful,
  12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14 * GNU General Public License for more details.
  15 */
  16
  17#include <linux/cpu.h>
  18#include <linux/acpi.h>
  19#include <asm/msr.h>
  20#include <asm/tsc.h>
  21
  22struct lpit_residency_info {
  23        struct acpi_generic_address gaddr;
  24        u64 frequency;
  25        void __iomem *iomem_addr;
  26};
  27
  28/* Storage for an memory mapped and FFH based entries */
  29static struct lpit_residency_info residency_info_mem;
  30static struct lpit_residency_info residency_info_ffh;
  31
  32static int lpit_read_residency_counter_us(u64 *counter, bool io_mem)
  33{
  34        int err;
  35
  36        if (io_mem) {
  37                u64 count = 0;
  38                int error;
  39
  40                error = acpi_os_read_iomem(residency_info_mem.iomem_addr, &count,
  41                                           residency_info_mem.gaddr.bit_width);
  42                if (error)
  43                        return error;
  44
  45                *counter = div64_u64(count * 1000000ULL, residency_info_mem.frequency);
  46                return 0;
  47        }
  48
  49        err = rdmsrl_safe(residency_info_ffh.gaddr.address, counter);
  50        if (!err) {
  51                u64 mask = GENMASK_ULL(residency_info_ffh.gaddr.bit_offset +
  52                                       residency_info_ffh.gaddr. bit_width - 1,
  53                                       residency_info_ffh.gaddr.bit_offset);
  54
  55                *counter &= mask;
  56                *counter >>= residency_info_ffh.gaddr.bit_offset;
  57                *counter = div64_u64(*counter * 1000000ULL, residency_info_ffh.frequency);
  58                return 0;
  59        }
  60
  61        return -ENODATA;
  62}
  63
  64static ssize_t low_power_idle_system_residency_us_show(struct device *dev,
  65                                                       struct device_attribute *attr,
  66                                                       char *buf)
  67{
  68        u64 counter;
  69        int ret;
  70
  71        ret = lpit_read_residency_counter_us(&counter, true);
  72        if (ret)
  73                return ret;
  74
  75        return sprintf(buf, "%llu\n", counter);
  76}
  77static DEVICE_ATTR_RO(low_power_idle_system_residency_us);
  78
  79static ssize_t low_power_idle_cpu_residency_us_show(struct device *dev,
  80                                                    struct device_attribute *attr,
  81                                                    char *buf)
  82{
  83        u64 counter;
  84        int ret;
  85
  86        ret = lpit_read_residency_counter_us(&counter, false);
  87        if (ret)
  88                return ret;
  89
  90        return sprintf(buf, "%llu\n", counter);
  91}
  92static DEVICE_ATTR_RO(low_power_idle_cpu_residency_us);
  93
  94int lpit_read_residency_count_address(u64 *address)
  95{
  96        if (!residency_info_mem.gaddr.address)
  97                return -EINVAL;
  98
  99        *address = residency_info_mem.gaddr.address;
 100
 101        return 0;
 102}
 103EXPORT_SYMBOL_GPL(lpit_read_residency_count_address);
 104
 105static void lpit_update_residency(struct lpit_residency_info *info,
 106                                 struct acpi_lpit_native *lpit_native)
 107{
 108        info->frequency = lpit_native->counter_frequency ?
 109                                lpit_native->counter_frequency : tsc_khz * 1000;
 110        if (!info->frequency)
 111                info->frequency = 1;
 112
 113        info->gaddr = lpit_native->residency_counter;
 114        if (info->gaddr.space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY) {
 115                info->iomem_addr = ioremap_nocache(info->gaddr.address,
 116                                                   info->gaddr.bit_width / 8);
 117                if (!info->iomem_addr)
 118                        return;
 119
 120                /* Silently fail, if cpuidle attribute group is not present */
 121                sysfs_add_file_to_group(&cpu_subsys.dev_root->kobj,
 122                                        &dev_attr_low_power_idle_system_residency_us.attr,
 123                                        "cpuidle");
 124        } else if (info->gaddr.space_id == ACPI_ADR_SPACE_FIXED_HARDWARE) {
 125                /* Silently fail, if cpuidle attribute group is not present */
 126                sysfs_add_file_to_group(&cpu_subsys.dev_root->kobj,
 127                                        &dev_attr_low_power_idle_cpu_residency_us.attr,
 128                                        "cpuidle");
 129        }
 130}
 131
 132static void lpit_process(u64 begin, u64 end)
 133{
 134        while (begin + sizeof(struct acpi_lpit_native) < end) {
 135                struct acpi_lpit_native *lpit_native = (struct acpi_lpit_native *)begin;
 136
 137                if (!lpit_native->header.type && !lpit_native->header.flags) {
 138                        if (lpit_native->residency_counter.space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY &&
 139                            !residency_info_mem.gaddr.address) {
 140                                lpit_update_residency(&residency_info_mem, lpit_native);
 141                        } else if (lpit_native->residency_counter.space_id == ACPI_ADR_SPACE_FIXED_HARDWARE &&
 142                                   !residency_info_ffh.gaddr.address) {
 143                                lpit_update_residency(&residency_info_ffh, lpit_native);
 144                        }
 145                }
 146                begin += lpit_native->header.length;
 147        }
 148}
 149
 150void acpi_init_lpit(void)
 151{
 152        acpi_status status;
 153        u64 lpit_begin;
 154        struct acpi_table_lpit *lpit;
 155
 156        status = acpi_get_table(ACPI_SIG_LPIT, 0, (struct acpi_table_header **)&lpit);
 157
 158        if (ACPI_FAILURE(status))
 159                return;
 160
 161        lpit_begin = (u64)lpit + sizeof(*lpit);
 162        lpit_process(lpit_begin, lpit_begin + lpit->header.length);
 163}
 164