FreeBSD/Linux Kernel Cross Reference
sys/sys/cpu.h

     /*-
      * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
      *
      * Copyright (c) 2005-2007 Nate Lawson (SDG)
      * All rights reserved.
      *
      * Redistribution and use in source and binary forms, with or without
      * modification, are permitted provided that the following conditions
      * are met:
     * 1. Redistributions of source code must retain the above copyright
     *    notice, this list of conditions and the following disclaimer.
     * 2. Redistributions in binary form must reproduce the above copyright
     *    notice, this list of conditions and the following disclaimer in the
     *    documentation and/or other materials provided with the distribution.
     *
     * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
     * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
     * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     * SUCH DAMAGE.
     *
     * $FreeBSD$
     */
    
    #ifndef _SYS_CPU_H_
    #define _SYS_CPU_H_
    
    #include <sys/_eventhandler.h>
    
    /*
     * CPU device support.
     */
    
    #define CPU_IVAR_PCPU           1
    #define CPU_IVAR_NOMINAL_MHZ    2
    #define CPU_IVAR_CPUID_SIZE     3
    #define CPU_IVAR_CPUID          4
    
    static __inline struct pcpu *cpu_get_pcpu(device_t dev)
    {
            uintptr_t v = 0;
            BUS_READ_IVAR(device_get_parent(dev), dev, CPU_IVAR_PCPU, &v);
            return ((struct pcpu *)v);
    }
    
    static __inline int32_t cpu_get_nominal_mhz(device_t dev)
    {
            uintptr_t v = 0;
            if (BUS_READ_IVAR(device_get_parent(dev), dev,
                CPU_IVAR_NOMINAL_MHZ, &v) != 0)
                    return (-1);
            return ((int32_t)v);
    }
    
    static __inline const uint32_t *cpu_get_cpuid(device_t dev, size_t *count)
    {
            uintptr_t v = 0;
            if (BUS_READ_IVAR(device_get_parent(dev), dev,
                CPU_IVAR_CPUID_SIZE, &v) != 0)
                    return (NULL);
            *count = (size_t)v;
    
            if (BUS_READ_IVAR(device_get_parent(dev), dev,
                CPU_IVAR_CPUID, &v) != 0)
                    return (NULL);
            return ((const uint32_t *)v);
    }
    
    /*
     * CPU frequency control interface.
     */
    
    /* Each driver's CPU frequency setting is exported in this format. */
    struct cf_setting {
            int     freq;   /* CPU clock in Mhz or 100ths of a percent. */
            int     volts;  /* Voltage in mV. */
            int     power;  /* Power consumed in mW. */
            int     lat;    /* Transition latency in us. */
            device_t dev;   /* Driver providing this setting. */
            int     spec[4];/* Driver-specific storage for non-standard info. */
    };
    
    /* Maximum number of settings a given driver can have. */
    #define MAX_SETTINGS            256
    
    /* A combination of settings is a level. */
    struct cf_level {
            struct cf_setting       total_set;
            struct cf_setting       abs_set;
            struct cf_setting       rel_set[MAX_SETTINGS];
            int                     rel_count;
            TAILQ_ENTRY(cf_level)   link;
    };
   
   TAILQ_HEAD(cf_level_lst, cf_level);
   
   /* Drivers should set all unknown values to this. */
   #define CPUFREQ_VAL_UNKNOWN     (-1)
   
   /*
    * Every driver offers a type of CPU control.  Absolute levels are mutually
    * exclusive while relative levels modify the current absolute level.  There
    * may be multiple absolute and relative drivers available on a given
    * system.
    *
    * For example, consider a system with two absolute drivers that provide
    * frequency settings of 100, 200 and 300, 400 and a relative driver that
    * provides settings of 50%, 100%.  The cpufreq core would export frequency
    * levels of 50, 100, 150, 200, 300, 400.
    *
    * The "info only" flag signifies that settings returned by
    * CPUFREQ_DRV_SETTINGS cannot be passed to the CPUFREQ_DRV_SET method and
    * are only informational.  This is for some drivers that can return
    * information about settings but rely on another machine-dependent driver
    * for actually performing the frequency transition (e.g., ACPI performance
    * states of type "functional fixed hardware.")
    *
    * The "uncached" flag tells CPUFREQ_DRV_GET to try obtaining the real
    * instantaneous frequency from the underlying hardware regardless of cached
    * state. It is probably a bug to not combine this with "info only"
    */
   #define CPUFREQ_TYPE_MASK       0xffff
   #define CPUFREQ_TYPE_RELATIVE   (1<<0)
   #define CPUFREQ_TYPE_ABSOLUTE   (1<<1)
   #define CPUFREQ_FLAG_INFO_ONLY  (1<<16)
   #define CPUFREQ_FLAG_UNCACHED   (1<<17)
   
   /*
    * When setting a level, the caller indicates the priority of this request.
    * Priorities determine, among other things, whether a level can be
    * overridden by other callers.  For example, if the user sets a level but
    * the system thermal driver needs to override it for emergency cooling,
    * the driver would use a higher priority.  Once the event has passed, the
    * driver would call cpufreq to resume any previous level.
    */
   #define CPUFREQ_PRIO_HIGHEST    1000000
   #define CPUFREQ_PRIO_KERN       1000
   #define CPUFREQ_PRIO_USER       100
   #define CPUFREQ_PRIO_LOWEST     0
   
   /*
    * Register and unregister a driver with the cpufreq core.  Once a driver
    * is registered, it must support calls to its CPUFREQ_GET, CPUFREQ_GET_LEVEL,
    * and CPUFREQ_SET methods.  It must also unregister before returning from
    * its DEVICE_DETACH method.
    */
   int     cpufreq_register(device_t dev);
   int     cpufreq_unregister(device_t dev);
   
   /*
    * Notify the cpufreq core that the number of or values for settings have
    * changed.
    */
   int     cpufreq_settings_changed(device_t dev);
   
   /*
    * Eventhandlers that are called before and after a change in frequency.
    * The new level and the result of the change (0 is success) is passed in.
    * If the driver wishes to revoke the change from cpufreq_pre_change, it
    * stores a non-zero error code in the result parameter and the change will
    * not be made.  If the post-change eventhandler gets a non-zero result, 
    * no change was made and the previous level remains in effect.  If a change
    * is revoked, the post-change eventhandler is still called with the error
    * value supplied by the revoking driver.  This gives listeners who cached
    * some data in preparation for a level change a chance to clean up.
    */
   typedef void (*cpufreq_pre_notify_fn)(void *, const struct cf_level *, int *);
   typedef void (*cpufreq_post_notify_fn)(void *, const struct cf_level *, int);
   EVENTHANDLER_DECLARE(cpufreq_pre_change, cpufreq_pre_notify_fn);
   EVENTHANDLER_DECLARE(cpufreq_post_change, cpufreq_post_notify_fn);
   
   /*
    * Eventhandler called when the available list of levels changed.
    * The unit number of the device (i.e. "cpufreq0") whose levels changed
    * is provided so the listener can retrieve the new list of levels.
    */
   typedef void (*cpufreq_levels_notify_fn)(void *, int);
   EVENTHANDLER_DECLARE(cpufreq_levels_changed, cpufreq_levels_notify_fn);
   
   /* Allow values to be +/- a bit since sometimes we have to estimate. */
   #define CPUFREQ_CMP(x, y)       (abs((x) - (y)) < 25)
   
   /*
    * Machine-dependent functions.
    */
   
   /* Estimate the current clock rate for the given CPU id. */
   int     cpu_est_clockrate(int cpu_id, uint64_t *rate);
   
   #endif /* !_SYS_CPU_H_ */

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