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# include <linux/types.h>
# include <linux/errno.h>
# include <linux/kernel.h>
# include <linux/delay.h>
# include <linux/slab.h>
# include <linux/init.h>
# include <linux/wait.h>
# include <linux/cpufreq.h>
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# include <asm/prom.h>
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# include "windfarm.h"
# define VERSION "0.3"
static int clamped ;
static struct wf_control * clamp_control ;
static int clamp_notifier_call ( struct notifier_block * self ,
unsigned long event , void * data )
{
struct cpufreq_policy * p = data ;
unsigned long max_freq ;
if ( event ! = CPUFREQ_ADJUST )
return 0 ;
max_freq = clamped ? ( p - > cpuinfo . min_freq ) : ( p - > cpuinfo . max_freq ) ;
cpufreq_verify_within_limits ( p , 0 , max_freq ) ;
return 0 ;
}
static struct notifier_block clamp_notifier = {
. notifier_call = clamp_notifier_call ,
} ;
static int clamp_set ( struct wf_control * ct , s32 value )
{
if ( value )
printk ( KERN_INFO " windfarm: Clamping CPU frequency to "
" minimum ! \n " ) ;
else
printk ( KERN_INFO " windfarm: CPU frequency unclamped ! \n " ) ;
clamped = value ;
cpufreq_update_policy ( 0 ) ;
return 0 ;
}
static int clamp_get ( struct wf_control * ct , s32 * value )
{
* value = clamped ;
return 0 ;
}
static s32 clamp_min ( struct wf_control * ct )
{
return 0 ;
}
static s32 clamp_max ( struct wf_control * ct )
{
return 1 ;
}
static struct wf_control_ops clamp_ops = {
. set_value = clamp_set ,
. get_value = clamp_get ,
. get_min = clamp_min ,
. get_max = clamp_max ,
. owner = THIS_MODULE ,
} ;
static int __init wf_cpufreq_clamp_init ( void )
{
struct wf_control * clamp ;
clamp = kmalloc ( sizeof ( struct wf_control ) , GFP_KERNEL ) ;
if ( clamp = = NULL )
return - ENOMEM ;
cpufreq_register_notifier ( & clamp_notifier , CPUFREQ_POLICY_NOTIFIER ) ;
clamp - > ops = & clamp_ops ;
clamp - > name = " cpufreq-clamp " ;
if ( wf_register_control ( clamp ) )
goto fail ;
clamp_control = clamp ;
return 0 ;
fail :
kfree ( clamp ) ;
return - ENODEV ;
}
static void __exit wf_cpufreq_clamp_exit ( void )
{
if ( clamp_control )
wf_unregister_control ( clamp_control ) ;
}
module_init ( wf_cpufreq_clamp_init ) ;
module_exit ( wf_cpufreq_clamp_exit ) ;
MODULE_AUTHOR ( " Benjamin Herrenschmidt <benh@kernel.crashing.org> " ) ;
MODULE_DESCRIPTION ( " CPU frequency clamp for PowerMacs thermal control " ) ;
MODULE_LICENSE ( " GPL " ) ;