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Provide a new CPU device driver ivar to report the nominal speed of the

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CPU, if available. This is meant to solve the issue of cpufreq misreporting
speeds on CPUs that boot in a reduced power mode and have only relative
speed control.
This commit is contained in:
Nathan Whitehorn 2009-05-31 08:59:15 +00:00
parent c22ca7f04f
commit f436f17508
2 changed files with 31 additions and 12 deletions
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33
sys/kern/kern_cpu.c
View File

@ -158,12 +158,16 @@ cpufreq_attach(device_t dev)
CF_MTX_INIT(&sc->lock);
sc->curr_level.total_set.freq = CPUFREQ_VAL_UNKNOWN;
SLIST_INIT(&sc->saved_freq);
/* Try to get current CPU freq to use it as maximum later if needed */
pc = cpu_get_pcpu(dev);
if (cpu_est_clockrate(pc->pc_cpuid, &rate) == 0)
sc->max_mhz = rate / 1000000;
else
sc->max_mhz = CPUFREQ_VAL_UNKNOWN;
/* Try to get nominal CPU freq to use it as maximum later if needed */
sc->max_mhz = cpu_get_nominal_mhz(dev);
/* If that fails, try to measure the current rate */
if (sc->max_mhz <= 0) {
pc = cpu_get_pcpu(dev);
if (cpu_est_clockrate(pc->pc_cpuid, &rate) == 0)
sc->max_mhz = rate / 1000000;
else
sc->max_mhz = CPUFREQ_VAL_UNKNOWN;
}
/*
* Only initialize one set of sysctls for all CPUs. In the future,
@ -581,15 +585,20 @@ cf_levels_method(device_t dev, struct cf_level *levels, int *count)
/*
* If there are no absolute levels, create a fake one at 100%. We
* then cache the clockrate for later use as our base frequency.
*
* XXX This assumes that the first time through, if we only have
* relative drivers, the CPU is currently running at 100%.
*/
if (TAILQ_EMPTY(&sc->all_levels)) {
if (sc->max_mhz == CPUFREQ_VAL_UNKNOWN) {
pc = cpu_get_pcpu(dev);
cpu_est_clockrate(pc->pc_cpuid, &rate);
sc->max_mhz = rate / 1000000;
sc->max_mhz = cpu_get_nominal_mhz(dev);
/*
* If the CPU can't report a rate for 100%, hope
* the CPU is running at its nominal rate right now,
* and use that instead.
*/
if (sc->max_mhz <= 0) {
pc = cpu_get_pcpu(dev);
cpu_est_clockrate(pc->pc_cpuid, &rate);
sc->max_mhz = rate / 1000000;
}
}
memset(&sets[0], CPUFREQ_VAL_UNKNOWN, sizeof(*sets));
sets[0].freq = sc->max_mhz;

10
sys/sys/cpu.h
View File

@ -36,6 +36,7 @@
*/
#define CPU_IVAR_PCPU 1
#define CPU_IVAR_NOMINAL_MHZ 2
static __inline struct pcpu *cpu_get_pcpu(device_t dev)
{
@ -44,6 +45,15 @@ static __inline struct pcpu *cpu_get_pcpu(device_t dev)
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);
}
/*
* CPU frequency control interface.
*/