diff options
Diffstat (limited to 'drivers/acpi/acpi_lpit.c')
| -rw-r--r-- | drivers/acpi/acpi_lpit.c | 163 |
1 files changed, 163 insertions, 0 deletions
diff --git a/drivers/acpi/acpi_lpit.c b/drivers/acpi/acpi_lpit.c new file mode 100644 index 000000000000..cf4fc0161164 --- /dev/null +++ b/drivers/acpi/acpi_lpit.c @@ -0,0 +1,163 @@ + +/* + * acpi_lpit.c - LPIT table processing functions + * + * Copyright (C) 2017 Intel Corporation. All rights reserved. + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License version + * 2 as published by the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + */ + +#include <linux/cpu.h> +#include <linux/acpi.h> +#include <asm/msr.h> +#include <asm/tsc.h> + +struct lpit_residency_info { + struct acpi_generic_address gaddr; + u64 frequency; + void __iomem *iomem_addr; +}; + +/* Storage for an memory mapped and FFH based entries */ +static struct lpit_residency_info residency_info_mem; +static struct lpit_residency_info residency_info_ffh; + +static int lpit_read_residency_counter_us(u64 *counter, bool io_mem) +{ + int err; + + if (io_mem) { + u64 count = 0; + int error; + + error = acpi_os_read_iomem(residency_info_mem.iomem_addr, &count, + residency_info_mem.gaddr.bit_width); + if (error) + return error; + + *counter = div64_u64(count * 1000000ULL, residency_info_mem.frequency); + return 0; + } + + err = rdmsrl_safe(residency_info_ffh.gaddr.address, counter); + if (!err) { + u64 mask = GENMASK_ULL(residency_info_ffh.gaddr.bit_offset + + residency_info_ffh.gaddr. bit_width - 1, + residency_info_ffh.gaddr.bit_offset); + + *counter &= mask; + *counter >>= residency_info_ffh.gaddr.bit_offset; + *counter = div64_u64(*counter * 1000000ULL, residency_info_ffh.frequency); + return 0; + } + + return -ENODATA; +} + +static ssize_t low_power_idle_system_residency_us_show(struct device *dev, + struct device_attribute *attr, + char *buf) +{ + u64 counter; + int ret; + + ret = lpit_read_residency_counter_us(&counter, true); + if (ret) + return ret; + + return sprintf(buf, "%llu\n", counter); +} +static DEVICE_ATTR_RO(low_power_idle_system_residency_us); + +static ssize_t low_power_idle_cpu_residency_us_show(struct device *dev, + struct device_attribute *attr, + char *buf) +{ + u64 counter; + int ret; + + ret = lpit_read_residency_counter_us(&counter, false); + if (ret) + return ret; + + return sprintf(buf, "%llu\n", counter); +} +static DEVICE_ATTR_RO(low_power_idle_cpu_residency_us); + +int lpit_read_residency_count_address(u64 *address) +{ + if (!residency_info_mem.gaddr.address) + return -EINVAL; + + *address = residency_info_mem.gaddr.address; + + return 0; +} +EXPORT_SYMBOL_GPL(lpit_read_residency_count_address); + +static void lpit_update_residency(struct lpit_residency_info *info, + struct acpi_lpit_native *lpit_native) +{ + info->frequency = lpit_native->counter_frequency ? + lpit_native->counter_frequency : tsc_khz * 1000; + if (!info->frequency) + info->frequency = 1; + + info->gaddr = lpit_native->residency_counter; + if (info->gaddr.space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY) { + info->iomem_addr = ioremap_nocache(info->gaddr.address, + info->gaddr.bit_width / 8); + if (!info->iomem_addr) + return; + + /* Silently fail, if cpuidle attribute group is not present */ + sysfs_add_file_to_group(&cpu_subsys.dev_root->kobj, + &dev_attr_low_power_idle_system_residency_us.attr, + "cpuidle"); + } else if (info->gaddr.space_id == ACPI_ADR_SPACE_FIXED_HARDWARE) { + /* Silently fail, if cpuidle attribute group is not present */ + sysfs_add_file_to_group(&cpu_subsys.dev_root->kobj, + &dev_attr_low_power_idle_cpu_residency_us.attr, + "cpuidle"); + } +} + +static void lpit_process(u64 begin, u64 end) +{ + while (begin + sizeof(struct acpi_lpit_native) < end) { + struct acpi_lpit_native *lpit_native = (struct acpi_lpit_native *)begin; + + if (!lpit_native->header.type && !lpit_native->header.flags) { + if (lpit_native->residency_counter.space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY && + !residency_info_mem.gaddr.address) { + lpit_update_residency(&residency_info_mem, lpit_native); + } else if (lpit_native->residency_counter.space_id == ACPI_ADR_SPACE_FIXED_HARDWARE && + !residency_info_ffh.gaddr.address) { + lpit_update_residency(&residency_info_ffh, lpit_native); + } + } + begin += lpit_native->header.length; + } +} + +void acpi_init_lpit(void) +{ + acpi_status status; + u64 lpit_begin; + struct acpi_table_lpit *lpit; + + status = acpi_get_table(ACPI_SIG_LPIT, 0, (struct acpi_table_header **)&lpit); + + if (ACPI_FAILURE(status)) + return; + + lpit_begin = (u64)lpit + sizeof(*lpit); + lpit_process(lpit_begin, lpit_begin + lpit->header.length); +} |