[RFC PATCHv2 1/2] Export SoC info through sysfs
Arnd Bergmann
arnd at arndb.de
Fri Mar 11 09:32:51 EST 2011
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.
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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