[RFC PATCHv2 1/2] Export SoC info through sysfs
Ben Dooks
ben-linux at fluff.org
Fri Mar 11 10:40:17 EST 2011
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?
> 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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--
Ben Dooks, ben at fluff.org, http://www.fluff.org/ben/
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