linux-kernel - Re: [PATCH 02/13] coresight: cti: Add sysfs coresight mgmt register access

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Date:   Wed, 18 Mar 2020 12:16:04 -0600
From:   Mathieu Poirier <mathieu.poirier@...aro.org>
To:     Greg KH <gregkh@...uxfoundation.org>
Cc:     linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 02/13] coresight: cti: Add sysfs coresight mgmt register
 access

On Wed, Mar 18, 2020 at 02:18:21PM +0100, Greg KH wrote:
> On Mon, Mar 09, 2020 at 10:17:37AM -0600, Mathieu Poirier wrote:
> > From: Mike Leach <mike.leach@...aro.org>
> > 
> > Adds sysfs access to the coresight management registers.
> > 
> > Signed-off-by: Mike Leach <mike.leach@...aro.org>
> > Reviewed-by: Mathieu Poirier <mathieu.poirier@...aro.org>
> > Reviewed-by: Suzuki K Poulose <suzuki.poulose@....com>
> > [Fixed abbreviation in title]
> > Signed-off-by: Mathieu Poirier <mathieu.poirier@...aro.org>
> > ---
> >  .../hwtracing/coresight/coresight-cti-sysfs.c | 53 +++++++++++++++++++
> >  drivers/hwtracing/coresight/coresight-priv.h  |  1 +
> >  2 files changed, 54 insertions(+)
> > 
> > diff --git a/drivers/hwtracing/coresight/coresight-cti-sysfs.c b/drivers/hwtracing/coresight/coresight-cti-sysfs.c
> > index a832b8c6b866..507f8eb487fe 100644
> > --- a/drivers/hwtracing/coresight/coresight-cti-sysfs.c
> > +++ b/drivers/hwtracing/coresight/coresight-cti-sysfs.c
> > @@ -62,11 +62,64 @@ static struct attribute *coresight_cti_attrs[] = {
> >  	NULL,
> >  };
> >  
> > +/* register based attributes */
> > +
> > +/* macro to access RO registers with power check only (no enable check). */
> > +#define coresight_cti_reg(name, offset)			\
> > +static ssize_t name##_show(struct device *dev,				\
> > +			   struct device_attribute *attr, char *buf)	\
> > +{									\
> > +	struct cti_drvdata *drvdata = dev_get_drvdata(dev->parent);	\
> > +	u32 val = 0;							\
> > +	pm_runtime_get_sync(dev->parent);				\
> > +	spin_lock(&drvdata->spinlock);					\
> > +	if (drvdata->config.hw_powered)					\
> > +		val = readl_relaxed(drvdata->base + offset);		\
> > +	spin_unlock(&drvdata->spinlock);				\
> > +	pm_runtime_put_sync(dev->parent);				\
> > +	return scnprintf(buf, PAGE_SIZE, "0x%x\n", val);		\
> > +}									\
> > +static DEVICE_ATTR_RO(name)
> > +
> > +/* coresight management registers */
> > +coresight_cti_reg(devaff0, CTIDEVAFF0);
> > +coresight_cti_reg(devaff1, CTIDEVAFF1);
> > +coresight_cti_reg(authstatus, CORESIGHT_AUTHSTATUS);
> > +coresight_cti_reg(devarch, CORESIGHT_DEVARCH);
> > +coresight_cti_reg(devid, CORESIGHT_DEVID);
> > +coresight_cti_reg(devtype, CORESIGHT_DEVTYPE);
> > +coresight_cti_reg(pidr0, CORESIGHT_PERIPHIDR0);
> > +coresight_cti_reg(pidr1, CORESIGHT_PERIPHIDR1);
> > +coresight_cti_reg(pidr2, CORESIGHT_PERIPHIDR2);
> > +coresight_cti_reg(pidr3, CORESIGHT_PERIPHIDR3);
> > +coresight_cti_reg(pidr4, CORESIGHT_PERIPHIDR4);
> > +
> > +static struct attribute *coresight_cti_mgmt_attrs[] = {
> > +	&dev_attr_devaff0.attr,
> > +	&dev_attr_devaff1.attr,
> > +	&dev_attr_authstatus.attr,
> > +	&dev_attr_devarch.attr,
> > +	&dev_attr_devid.attr,
> > +	&dev_attr_devtype.attr,
> > +	&dev_attr_pidr0.attr,
> > +	&dev_attr_pidr1.attr,
> > +	&dev_attr_pidr2.attr,
> > +	&dev_attr_pidr3.attr,
> > +	&dev_attr_pidr4.attr,
> > +	NULL,
> > +};
> > +
> >  static const struct attribute_group coresight_cti_group = {
> >  	.attrs = coresight_cti_attrs,
> >  };
> >  
> > +static const struct attribute_group coresight_cti_mgmt_group = {
> > +	.attrs = coresight_cti_mgmt_attrs,
> > +	.name = "mgmt",
> > +};
> > +
> >  const struct attribute_group *coresight_cti_groups[] = {
> >  	&coresight_cti_group,
> > +	&coresight_cti_mgmt_group,
> >  	NULL,
> >  };
> > diff --git a/drivers/hwtracing/coresight/coresight-priv.h b/drivers/hwtracing/coresight/coresight-priv.h
> > index 82e563cdc879..aba6b789c969 100644
> > --- a/drivers/hwtracing/coresight/coresight-priv.h
> > +++ b/drivers/hwtracing/coresight/coresight-priv.h
> > @@ -22,6 +22,7 @@
> >  #define CORESIGHT_CLAIMCLR	0xfa4
> >  #define CORESIGHT_LAR		0xfb0
> >  #define CORESIGHT_LSR		0xfb4
> > +#define CORESIGHT_DEVARCH	0xfbc
> >  #define CORESIGHT_AUTHSTATUS	0xfb8
> >  #define CORESIGHT_DEVID		0xfc8
> >  #define CORESIGHT_DEVTYPE	0xfcc
> > -- 
> > 2.20.1
> > 
> 
> I do not see any Documentation/ABI/ entries for these new sysfs files,
> did I miss it somehow?  I can't take new sysfs code without
> documentation.

All the ABI is documented in this patch, which is part of this set.

[1]. https://lkml.org/lkml/2020/3/9/642

Thanks,
Mathieu

> 
> thanks,
> 
> greg k-h