> -----Original Message-----
> From: Wang Dongsheng-B40534
> Sent: Thursday, October 17, 2013 8:16 AM
> To: Bhushan Bharat-R65777; Wood Scott-B07421
> Cc: linuxppc-dev@lists.ozlabs.org
> Subject: RE: [PATCH v5 4/4] powerpc/85xx: add sysfs for pw20 state and altivec
> idle
>
>
>
> > -----Original Message-----
> > From: Bhushan Bharat-R65777
> > Sent: Thursday, October 17, 2013 1:01 AM
> > To: Wang Dongsheng-B40534; Wood Scott-B07421
> > Cc: linuxppc-dev@lists.ozlabs.org
> > Subject: RE: [PATCH v5 4/4] powerpc/85xx: add sysfs for pw20 state and
> > altivec idle
> >
> >
> >
> > > -----Original Message-----
> > > From: Wang Dongsheng-B40534
> > > Sent: Tuesday, October 15, 2013 2:51 PM
> > > To: Wood Scott-B07421
> > > Cc: Bhushan Bharat-R65777; linuxppc-dev@lists.ozlabs.org; Wang
> > Dongsheng-B40534
> > > Subject: [PATCH v5 4/4] powerpc/85xx: add sysfs for pw20 state and
> > altivec idle
> > >
> > > From: Wang Dongsheng <dongsheng.w...@freescale.com>
> > >
> > > Add a sys interface to enable/diable pw20 state or altivec idle, and
> > control the
> > > wait entry time.
> > >
> > > Enable/Disable interface:
> > > 0, disable. 1, enable.
> > > /sys/devices/system/cpu/cpuX/pw20_state
> > > /sys/devices/system/cpu/cpuX/altivec_idle
> > >
> > > Set wait time interface:(Nanosecond)
> > > /sys/devices/system/cpu/cpuX/pw20_wait_time
> > > /sys/devices/system/cpu/cpuX/altivec_idle_wait_time
> > > Example: Base on TBfreq is 41MHZ.
> > > 1~48(ns): TB[63]
> > > 49~97(ns): TB[62]
> > > 98~195(ns): TB[61]
> > > 196~390(ns): TB[60]
> > > 391~780(ns): TB[59]
> > > 781~1560(ns): TB[58]
> > > ...
> > >
> > > Signed-off-by: Wang Dongsheng <dongsheng.w...@freescale.com>
> > > ---
> > > *v5:
> > > Change get_idle_ticks_bit function implementation.
> > >
> > > *v4:
> > > Move code from 85xx/common.c to kernel/sysfs.c.
> > >
> > > Remove has_pw20_altivec_idle function.
> > >
> > > Change wait "entry_bit" to wait time.
> > >
> > > diff --git a/arch/powerpc/kernel/sysfs.c
> > > b/arch/powerpc/kernel/sysfs.c
> > index
> > > 27a90b9..10d1128 100644
> > > --- a/arch/powerpc/kernel/sysfs.c
> > > +++ b/arch/powerpc/kernel/sysfs.c
> > > @@ -85,6 +85,284 @@ __setup("smt-snooze-delay=",
> > setup_smt_snooze_delay);
> > >
> > > #endif /* CONFIG_PPC64 */
> > >
> > > +#ifdef CONFIG_FSL_SOC
> > > +#define MAX_BIT 63
> > > +
> > > +static u64 pw20_wt;
> > > +static u64 altivec_idle_wt;
> > > +
> > > +static unsigned int get_idle_ticks_bit(u64 ns) {
> > > + u64 cycle;
> > > +
> > > + if (ns >= 10000)
> > > + cycle = div_u64(ns + 500, 1000) * tb_ticks_per_usec;
> > > + else
> > > + cycle = div_u64(ns * tb_ticks_per_usec, 1000);
> > > +
> > > + if (!cycle)
> > > + return 0;
> > > +
> > > + return ilog2(cycle);
> > > +}
> > > +
> > > +static void do_show_pwrmgtcr0(void *val) {
> > > + u32 *value = val;
> > > +
> > > + *value = mfspr(SPRN_PWRMGTCR0);
> > > +}
> > > +
> > > +static ssize_t show_pw20_state(struct device *dev,
> > > + struct device_attribute *attr, char *buf) {
> > > + u32 value;
> > > + unsigned int cpu = dev->id;
> > > +
> > > + smp_call_function_single(cpu, do_show_pwrmgtcr0, &value, 1);
> > > +
> > > + value &= PWRMGTCR0_PW20_WAIT;
> > > +
> > > + return sprintf(buf, "%u\n", value ? 1 : 0); }
> > > +
> > > +static void do_store_pw20_state(void *val) {
> > > + u32 *value = val;
> > > + u32 pw20_state;
> > > +
> > > + pw20_state = mfspr(SPRN_PWRMGTCR0);
> > > +
> > > + if (*value)
> > > + pw20_state |= PWRMGTCR0_PW20_WAIT;
> > > + else
> > > + pw20_state &= ~PWRMGTCR0_PW20_WAIT;
> > > +
> > > + mtspr(SPRN_PWRMGTCR0, pw20_state); }
> > > +
> > > +static ssize_t store_pw20_state(struct device *dev,
> > > + struct device_attribute *attr,
> > > + const char *buf, size_t count)
> > > +{
> > > + u32 value;
> > > + unsigned int cpu = dev->id;
> > > +
> > > + if (kstrtou32(buf, 0, &value))
> > > + return -EINVAL;
> > > +
> > > + if (value > 1)
> > > + return -EINVAL;
> > > +
> > > + smp_call_function_single(cpu, do_store_pw20_state, &value, 1);
> > > +
> > > + return count;
> > > +}
> > > +
> > > +static ssize_t show_pw20_wait_time(struct device *dev,
> > > + struct device_attribute *attr, char *buf) {
> > > + u32 value;
> > > + u64 tb_cycle;
> > > + s64 time;
> > > +
> > > + unsigned int cpu = dev->id;
> > > +
> > > + if (!pw20_wt) {
> > > + smp_call_function_single(cpu, do_show_pwrmgtcr0, &value, 1);
> > > + value = (value & PWRMGTCR0_PW20_ENT) >>
> > > + PWRMGTCR0_PW20_ENT_SHIFT;
> > > +
> > > + tb_cycle = (1 << (MAX_BIT - value)) * 2;
> >
> > Is value = 0 and value = 1 legal? These will make tb_cycle = 0,
> >
> > > + time = div_u64(tb_cycle * 1000, tb_ticks_per_usec) - 1;
> >
> > And time = -1;
> >
> Please look at the end of the function, :)
>
> "return sprintf(buf, "%llu\n", time > 0 ? time : 0);"
I know you return 0 if value = 0/1, my question was that, is this correct as
per specification?
Ahh, also for "value" upto 7 you will return 0, no?
-Bharat
>
> -dongsheng
>
> >
> > > + } else {
> > > + time = pw20_wt;
> > > + }
> > > +
> > > + return sprintf(buf, "%llu\n", time > 0 ? time : 0);
> > > }
> > > +
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