[RFC PATCHv2 1/2] Export SoC info through sysfs
Eduardo Valentin
eduardo.valentin at nokia.com
Fri Mar 11 12:38:38 EST 2011
On Fri, Mar 11, 2011 at 03:40:17PM +0000, ext Ben Dooks wrote:
> On Fri, Mar 11, 2011 at 03:32:51PM +0100, Arnd Bergmann wrote:
> > On Friday 11 March 2011, Maxime Coquelin wrote:
> > > Common base to export System-on-Chip related informations through sysfs.
> > >
> > > Creation of a "socinfo" directory under /sys/.
> > > Creation of SoC information entries.
> > >
> > > Signed-off-by: Maxime COQUELIN <maxime.coquelin-nonst at stericsson.com>
> >
> > I think it's better than the previous patch to create an
> > artificial device in /sys/devices/system/socinfo, but I'd
> > still prefer the information to be attached to a real device
> > that represents the SOC, as I explained in the discussion with
> > Linus Walleij.
>
> Why not create it under the cpu directory?
I think it is mainly because people have strong opinion against
merging/confusing soc data with cpu data.
>
> > You should definitely add Greg on Cc, as he's maintaining sysfs
> > and certainly has an opininion here.
> >
> > Arnd
> >
> > > ---
> > > Documentation/ABI/testing/sysfs-socinfo | 16 ++++++
> > > drivers/base/Kconfig | 3 +
> > > drivers/base/Makefile | 1 +
> > > drivers/base/soc.c | 79 +++++++++++++++++++++++++++++++
> > > include/linux/sys_soc.h | 50 +++++++++++++++++++
> > > 5 files changed, 149 insertions(+), 0 deletions(-)
> > > create mode 100644 Documentation/ABI/testing/sysfs-socinfo
> > > create mode 100644 drivers/base/soc.c
> > > create mode 100644 include/linux/sys_soc.h
> > >
> > > diff --git a/Documentation/ABI/testing/sysfs-socinfo b/Documentation/ABI/testing/sysfs-socinfo
> > > new file mode 100644
> > > index 0000000..afd9da2
> > > --- /dev/null
> > > +++ b/Documentation/ABI/testing/sysfs-socinfo
> > > @@ -0,0 +1,16 @@
> > > +What: /sys/socinfo
> > > +Date: March 2011
> > > +contact: Maxime Coquelin <maxime.coquelin-nonst at stericsson.com>
> > > +Description:
> > > + The /sys/socinfo directory contains information about the
> > > + System-on-Chip. It is only available if platform implements it.
> > > + This directory contains two kind of attributes :
> > > + - common attributes:
> > > + * machine: the name of the machine.
> > > + * family: the family name of the SoC
> > > + - SoC-specific attributes: The SoC vendor can declare attributes
> > > + to export some strings to user-space, like the serial-number for
> > > + example.
> > > +
> > > +Users:
> > > + User-space applications which needs these kind of attributes.
> > > diff --git a/drivers/base/Kconfig b/drivers/base/Kconfig
> > > index d57e8d0..372ef3a 100644
> > > --- a/drivers/base/Kconfig
> > > +++ b/drivers/base/Kconfig
> > > @@ -168,4 +168,7 @@ config SYS_HYPERVISOR
> > > bool
> > > default n
> > >
> > > +config SYS_SOC
> > > + bool
> > > +
> > > endmenu
> > > diff --git a/drivers/base/Makefile b/drivers/base/Makefile
> > > index 5f51c3b..f3bcfb3 100644
> > > --- a/drivers/base/Makefile
> > > +++ b/drivers/base/Makefile
> > > @@ -18,6 +18,7 @@ ifeq ($(CONFIG_SYSFS),y)
> > > obj-$(CONFIG_MODULES) += module.o
> > > endif
> > > obj-$(CONFIG_SYS_HYPERVISOR) += hypervisor.o
> > > +obj-$(CONFIG_SYS_SOC) += soc.o
> > >
> > > ccflags-$(CONFIG_DEBUG_DRIVER) := -DDEBUG
> > >
> > > diff --git a/drivers/base/soc.c b/drivers/base/soc.c
> > > new file mode 100644
> > > index 0000000..046b43b
> > > --- /dev/null
> > > +++ b/drivers/base/soc.c
> > > @@ -0,0 +1,79 @@
> > > +/*
> > > + * Copyright (C) ST-Ericsson SA 2011
> > > + * Author: Maxime Coquelin <maxime.coquelin-nonst at stericsson.com> for ST-Ericsson.
> > > + * License terms: GNU General Public License (GPL), version 2
> > > + */
> > > +
> > > +#include <linux/sysfs.h>
> > > +#include <linux/module.h>
> > > +#include <linux/init.h>
> > > +#include <linux/stat.h>
> > > +#include <linux/slab.h>
> > > +#include <linux/sys_soc.h>
> > > +
> > > +struct kobject *soc_object;
> > > +
> > > +ssize_t show_soc_info(struct kobject *kobj,
> > > + struct kobj_attribute *attr, char *buf)
> > > +{
> > > + struct sysfs_soc_info *si = container_of(attr,
> > > + struct sysfs_soc_info, attr);
> > > +
> > > + if (si->info)
> > > + return sprintf(buf, "%s\n", si->info);
> > > +
> > > + return si->get_info(buf, si);
> > > +}
> >
> > I think this can be simplified by just letting the soc
> > register its own show method instead of the get_info function.
> >
> > > +int __init register_sysfs_soc_info(struct sysfs_soc_info *info, int nb_info)
> > > +{
> > > + int i, ret;
> > > +
> > > + for (i = 0; i < nb_info; i++) {
> > > + ret = sysfs_create_file(soc_object, &info[i].attr.attr);
> > > + if (ret) {
> > > + for (i -= 1; i >= 0; i--)
> > > + sysfs_remove_file(soc_object, &info[i].attr.attr);
> > > + break;
> > > + }
> > > + }
> > > +
> > > + return ret;
> > > +}
> > > +
> > > +static struct attribute *soc_attrs[] = {
> > > + NULL,
> > > +};
> > > +
> > > +static struct attribute_group soc_attr_group = {
> > > + .attrs = soc_attrs,
> > > +};
> > > +
> > > +int __init register_sysfs_soc(struct sysfs_soc_info *info, size_t num)
> > > +{
> > > + int ret;
> > > +
> > > + soc_object = kobject_create_and_add("socinfo", NULL);
> > > + if (!soc_object) {
> > > + ret = -ENOMEM;
> > > + goto exit;
> > > + }
> > > +
> > > + ret = sysfs_create_group(soc_object, &soc_attr_group);
> > > + if (ret)
> > > + goto kset_exit;
> > > +
> > > + ret = register_sysfs_soc_info(info, num);
> > > + if (ret)
> > > + goto group_exit;
> > > +
> > > + return 0;
> > > +
> > > +group_exit:
> > > + sysfs_remove_group(soc_object, &soc_attr_group);
> > > +kset_exit:
> > > + kobject_put(soc_object);
> > > +exit:
> > > + return ret;
> > > +}
> > > +
> > > diff --git a/include/linux/sys_soc.h b/include/linux/sys_soc.h
> > > new file mode 100644
> > > index 0000000..05e5529
> > > --- /dev/null
> > > +++ b/include/linux/sys_soc.h
> > > @@ -0,0 +1,50 @@
> > > +/*
> > > + * Copyright (C) ST-Ericsson SA 2011
> > > + * Author: Maxime Coquelin <maxime.coquelin-nonst at stericsson.com> for ST-Ericsson.
> > > + * License terms: GNU General Public License (GPL), version 2
> > > + */
> > > +#ifndef __SYS_SOC_H
> > > +#define __SYS_SOC_H
> > > +
> > > +#include <linux/kobject.h>
> > > +
> > > +/**
> > > + * struct sys_soc_info - SoC exports related informations
> > > + * @name: name of the export
> > > + * @info: pointer on the key to export
> > > + * @get_info: callback to retrieve key if info field is NULL
> > > + * @attr: export's sysdev class attribute
> > > + */
> > > +struct sysfs_soc_info {
> > > + const char *info;
> > > + ssize_t (*get_info)(char *buf, struct sysfs_soc_info *);
> > > + struct kobj_attribute attr;
> > > +};
> > > +
> > > +ssize_t show_soc_info(struct kobject *, struct kobj_attribute *, char *);
> > > +
> > > +#define SYSFS_SOC_ATTR_VALUE(_name, _value) { \
> > > + .attr.attr.name = _name, \
> > > + .attr.attr.mode = S_IRUGO, \
> > > + .attr.show = show_soc_info, \
> > > + .info = _value, \
> > > +}
> > > +
> > > +#define SYSFS_SOC_ATTR_CALLBACK(_name, _callback) { \
> > > + .attr.attr.name = _name, \
> > > + .attr.attr.mode = S_IRUGO, \
> > > + .attr.show = show_soc_info, \
> > > + .get_info = _callback, \
> > > +}
> > > +
> > > +/**
> > > + * register_sys_soc - register the soc information
> > > + * @name: name of the machine
> > > + * @info: pointer on the info table to export
> > > + * @num: number of info to export
> > > + *
> > > + * NOTE: This function must only be called once
> > > + */
> > > +int register_sysfs_soc(struct sysfs_soc_info *info, size_t num);
> > > +
> > > +#endif /* __SYS_SOC_H */
> > > --
> >
> > _______________________________________________
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> > linux-arm-kernel at lists.infradead.org
> > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
>
> --
> Ben Dooks, ben at fluff.org, http://www.fluff.org/ben/
>
> Large Hadron Colada: A large Pina Colada that makes the universe disappear.
--
Eduardo Valentin
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