linux-imx

​

/*

 * 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;

}

​