Re: [RFC][Patch] OMAP3 PM: sysfs vdd_opp change to use Constraint Framework

[Tony Lindgren <tony@atomide.com>]

* Kevin Hilman <khilman@deeprootsystems.com> [091020 08:51]:
> "Sripathy, Vishwanath" <vishwanath.bs@ti.com> writes:
> 
> > Sysfs entry vdd_opp currently does not use constraint framework. 
> > Because of this, even if you set the opp via this entry, it has no effect 
> > since it can be overridden by on demand governor any time.
> > This patch has changes to make vdd_opp to use constraint framework. 
> > vdd_lock variable has to be used when application wants to disable DVFS
> > altogether. This will override any other constraints and will lock the
> > OPP to given value.
> >
> > Signed-off-by: Vishwanath BS <vishwanath.bs@ti.com>
> 
> This raises an issue that I've been thinking about for awhile.
> 
> Basically, I'd like to drop all the /sys/power/vdd* options.
> 
> Since we can do the equivalent with CPUFreq using the userspace
> governor, I don't see the point of having an additional interface.
> 
> Comments?

Total ack from me!

Tony

> 
> Kevin
> 
> > ---
> >
> > diff --git a/arch/arm/mach-omap2/pm.c b/arch/arm/mach-omap2/pm.c
> > index 13783f3..bcdc00d 100644
> > --- a/arch/arm/mach-omap2/pm.c
> > +++ b/arch/arm/mach-omap2/pm.c
> > @@ -47,6 +47,8 @@ static ssize_t idle_store(struct kobject *k, struct kobj_attribute *,
> >  static ssize_t vdd_opp_show(struct kobject *, struct kobj_attribute *, char *);
> >  static ssize_t vdd_opp_store(struct kobject *k, struct kobj_attribute *,
> >  			  const char *buf, size_t n);
> > +static ssize_t vdd_opp_lock_store(struct kobject *k, struct kobj_attribute *,
> > +			  const char *buf, size_t n);
> >  static struct kobj_attribute vdd1_opp_attr =
> >  	__ATTR(vdd1_opp, 0644, vdd_opp_show, vdd_opp_store);
> >  
> > @@ -103,6 +105,41 @@ static ssize_t vdd_opp_store(struct kobject *kobj, struct kobj_attribute *attr,
> >  			  const char *buf, size_t n)
> >  {
> >  	unsigned short value;
> > +	struct omap_opp *opp_table;
> > +
> > +	if (sscanf(buf, "%hu", &value) != 1)
> > +		return -EINVAL;
> > +
> > +	if (attr == &vdd1_opp_attr) {
> > +		if (value < MIN_VDD1_OPP || value > MAX_VDD1_OPP) {
> > +			printk(KERN_ERR "vdd_opp_store: Invalid value\n");
> > +			return -EINVAL;
> > +		}
> > +		opp_table = omap_get_mpu_rate_table();
> > +		omap_pm_cpu_set_freq(&sysfs_cpufreq_dev,
> > +					opp_table[value].rate);
> > +	} else if (attr == &vdd2_opp_attr) {
> > +		if (value < MIN_VDD2_OPP || (value > MAX_VDD2_OPP)) {
> > +			printk(KERN_ERR "vdd_opp_store: Invalid value\n");
> > +			return -EINVAL;
> > +		}
> > +		if (value == VDD2_OPP2)
> > +			omap_pm_set_min_bus_tput(&sysfs_cpufreq_dev,
> > +					OCP_INITIATOR_AGENT, 83*1000*4);
> > +		else if (value == VDD2_OPP3)
> > +			omap_pm_set_min_bus_tput(&sysfs_cpufreq_dev,
> > +					OCP_INITIATOR_AGENT, 166*1000*4);
> > +
> > +	} else {
> > +		return -EINVAL;
> > +	}
> > +	return n;
> > +}
> > +
> > +static ssize_t vdd_opp_lock_store(struct kobject *kobj,
> > +	struct kobj_attribute *attr, const char *buf, size_t n)
> > +{
> > +	unsigned short value;
> >  	int flags = 0;
> >  
> >  	if (sscanf(buf, "%hu", &value) != 1)
> > @@ -121,6 +158,11 @@ static ssize_t vdd_opp_store(struct kobject *kobj, struct kobj_attribute *attr,
> >  		if (vdd1_locked == 0 && value != 0) {
> >  			resource_lock_opp(VDD1_OPP);
> >  			vdd1_locked = 1;
> > +			if (value < MIN_VDD1_OPP || value > MAX_VDD1_OPP) {
> > +				printk(KERN_ERR "vdd_opp_store: Invalid value\n");
> > +				return -EINVAL;
> > +				}
> > +		resource_set_opp_level(VDD1_OPP, value, flags);
> >  		}
> >  	} else if (attr == &vdd2_lock_attr) {
> >  		flags = OPP_IGNORE_LOCK;
> > @@ -134,21 +176,12 @@ static ssize_t vdd_opp_store(struct kobject *kobj, struct kobj_attribute *attr,
> >  		if (vdd2_locked == 0 && value != 0) {
> >  			resource_lock_opp(VDD2_OPP);
> >  			vdd2_locked = 1;
> > +			if (value < MIN_VDD2_OPP || value > MAX_VDD2_OPP) {
> > +				printk(KERN_ERR "vdd_opp_store: Invalid value\n");
> > +				return -EINVAL;
> > +			}
> > +			resource_set_opp_level(VDD2_OPP, value, flags);
> >  		}
> > -	}
> > -
> > -	if (attr == &vdd1_opp_attr) {
> > -		if (value < 1 || value > 5) {
> > -			printk(KERN_ERR "vdd_opp_store: Invalid value\n");
> > -			return -EINVAL;
> > -		}
> > -		resource_set_opp_level(VDD1_OPP, value, flags);
> > -	} else if (attr == &vdd2_opp_attr) {
> > -		if (value < 2 || value > 3) {
> > -			printk(KERN_ERR "vdd_opp_store: Invalid value\n");
> > -			return -EINVAL;
> > -		}
> > -		resource_set_opp_level(VDD2_OPP, value, flags);
> >  	} else {
> >  		return -EINVAL;
> >  	}
> > --
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