1// SPDX-License-Identifier: GPL-2.0-only
  2
  3/*
  4 * acpi_lpit.c - LPIT table processing functions
  5 *
  6 * Copyright (C) 2017 Intel Corporation. All rights reserved.
  7 */
  8
  9#include <linux/cpu.h>
 10#include <linux/acpi.h>
 11#include <asm/msr.h>
 12#include <asm/tsc.h>
 13#include "internal.h"
 14
 15struct lpit_residency_info {
 16	struct acpi_generic_address gaddr;
 17	u64 frequency;
 18	void __iomem *iomem_addr;
 19};
 20
 21/* Storage for an memory mapped and FFH based entries */
 22static struct lpit_residency_info residency_info_mem;
 23static struct lpit_residency_info residency_info_ffh;
 24
 25static int lpit_read_residency_counter_us(u64 *counter, bool io_mem)
 26{
 27	int err;
 28
 29	if (io_mem) {
 30		u64 count = 0;
 31		int error;
 32
 33		error = acpi_os_read_iomem(residency_info_mem.iomem_addr, &count,
 34					   residency_info_mem.gaddr.bit_width);
 35		if (error)
 36			return error;
 37
 38		*counter = div64_u64(count * 1000000ULL, residency_info_mem.frequency);
 39		return 0;
 40	}
 41
 42	err = rdmsrl_safe(residency_info_ffh.gaddr.address, counter);
 43	if (!err) {
 44		u64 mask = GENMASK_ULL(residency_info_ffh.gaddr.bit_offset +
 45				       residency_info_ffh.gaddr. bit_width - 1,
 46				       residency_info_ffh.gaddr.bit_offset);
 47
 48		*counter &= mask;
 49		*counter >>= residency_info_ffh.gaddr.bit_offset;
 50		*counter = div64_u64(*counter * 1000000ULL, residency_info_ffh.frequency);
 51		return 0;
 52	}
 53
 54	return -ENODATA;
 55}
 56
 57static ssize_t low_power_idle_system_residency_us_show(struct device *dev,
 58						       struct device_attribute *attr,
 59						       char *buf)
 60{
 61	u64 counter;
 62	int ret;
 63
 64	ret = lpit_read_residency_counter_us(&counter, true);
 65	if (ret)
 66		return ret;
 67
 68	return sprintf(buf, "%llu\n", counter);
 69}
 70static DEVICE_ATTR_RO(low_power_idle_system_residency_us);
 71
 72static ssize_t low_power_idle_cpu_residency_us_show(struct device *dev,
 73						    struct device_attribute *attr,
 74						    char *buf)
 75{
 76	u64 counter;
 77	int ret;
 78
 79	ret = lpit_read_residency_counter_us(&counter, false);
 80	if (ret)
 81		return ret;
 82
 83	return sprintf(buf, "%llu\n", counter);
 84}
 85static DEVICE_ATTR_RO(low_power_idle_cpu_residency_us);
 86
 87int lpit_read_residency_count_address(u64 *address)
 88{
 89	if (!residency_info_mem.gaddr.address)
 90		return -EINVAL;
 91
 92	*address = residency_info_mem.gaddr.address;
 93
 94	return 0;
 95}
 96EXPORT_SYMBOL_GPL(lpit_read_residency_count_address);
 97
 98static void lpit_update_residency(struct lpit_residency_info *info,
 99				 struct acpi_lpit_native *lpit_native)
100{
101	struct device *dev_root = bus_get_dev_root(&cpu_subsys);
102
103	/* Silently fail, if cpuidle attribute group is not present */
104	if (!dev_root)
105		return;
106
107	info->frequency = lpit_native->counter_frequency ?
108				lpit_native->counter_frequency : mul_u32_u32(tsc_khz, 1000U);
109	if (!info->frequency)
110		info->frequency = 1;
111
112	info->gaddr = lpit_native->residency_counter;
113	if (info->gaddr.space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY) {
114		info->iomem_addr = ioremap(info->gaddr.address,
115						   info->gaddr.bit_width / 8);
116		if (!info->iomem_addr)
117			goto exit;
118
119		sysfs_add_file_to_group(&dev_root->kobj,
120					&dev_attr_low_power_idle_system_residency_us.attr,
121					"cpuidle");
122	} else if (info->gaddr.space_id == ACPI_ADR_SPACE_FIXED_HARDWARE) {
123		sysfs_add_file_to_group(&dev_root->kobj,
124					&dev_attr_low_power_idle_cpu_residency_us.attr,
125					"cpuidle");
126	}
127exit:
128	put_device(dev_root);
129}
130
131static void lpit_process(u64 begin, u64 end)
132{
133	while (begin + sizeof(struct acpi_lpit_native) <= end) {
134		struct acpi_lpit_native *lpit_native = (struct acpi_lpit_native *)begin;
135
136		if (!lpit_native->header.type && !lpit_native->header.flags) {
137			if (lpit_native->residency_counter.space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY &&
138			    !residency_info_mem.gaddr.address) {
139				lpit_update_residency(&residency_info_mem, lpit_native);
140			} else if (lpit_native->residency_counter.space_id == ACPI_ADR_SPACE_FIXED_HARDWARE &&
141				   !residency_info_ffh.gaddr.address) {
142				lpit_update_residency(&residency_info_ffh, lpit_native);
143			}
144		}
145		begin += lpit_native->header.length;
146	}
147}
148
149void acpi_init_lpit(void)
150{
151	acpi_status status;
152	struct acpi_table_lpit *lpit;
153
154	status = acpi_get_table(ACPI_SIG_LPIT, 0, (struct acpi_table_header **)&lpit);
155	if (ACPI_FAILURE(status))
156		return;
157
158	lpit_process((u64)lpit + sizeof(*lpit),
159		     (u64)lpit + lpit->header.length);
160
161	acpi_put_table((struct acpi_table_header *)lpit);
162}