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Date: Mon, 15 Aug 2016 17:22:05 +0800
From: Allen Hung <allen_hung@...l.com>
To: Jean Delvare <jdelvare@...e.com>,
Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
Russell King <rmk+kernel@....linux.org.uk>,
Gabriel Somlo <somlo@....edu>,
Bjorn Andersson <bjorn.andersson@...ymobile.com>,
Jens Wiklander <jens.wiklander@...aro.org>,
Andy Gross <agross@...eaurora.org>,
Arnd Bergmann <arnd@...db.de>,
Sudeep Holla <sudeep.holla@....com>,
Eric Anholt <eric@...olt.net>, linux-kernel@...r.kernel.org,
Mario Limonciello <Mario_Limonciello@...l.com>
Cc: Allen Hung <allen_hung@...l.com>
Subject: [PATCH v3 2/2] dmi-id: add dmi/id/oem group for exporting oem strings to sysfs
The oem strings in DMI system identification information of the BIOS have
been parsed and stored as dmi devices in dmi_scan.c but they are not
exported to userspace via sysfs.
The patch intends to export oem strings to sysfs device /sys/class/dmi/id.
As the number of oem strings are dynamic, a group "oem" is added to the
device and the strings will be added to the group as string1, string2, ...,
and stringN.
Signed-off-by: Allen Hung <allen_hung@...l.com>
---
drivers/firmware/Kconfig | 9 ++++
drivers/firmware/dmi-id.c | 116 ++++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 125 insertions(+)
diff --git a/drivers/firmware/Kconfig b/drivers/firmware/Kconfig
index 6664f11..885a6c9 100644
--- a/drivers/firmware/Kconfig
+++ b/drivers/firmware/Kconfig
@@ -119,6 +119,15 @@ config DMIID
information from userspace through /sys/class/dmi/id/ or if you want
DMI-based module auto-loading.
+config DMIID_OEM_STRINGS
+ bool "Export OEM strings in SMBIOS/DMI via sysfs to userspace"
+ depends on DMIID
+ default n
+ help
+ Say Y here if you want to query OEM strings (as part of the information
+ contained in SMBIOS/DMI system identification) from userspace through
+ /sys/class/dmi/id/oem/.
+
config DMI_SYSFS
tristate "DMI table support in sysfs"
depends on SYSFS && DMI
diff --git a/drivers/firmware/dmi-id.c b/drivers/firmware/dmi-id.c
index 44c0139..4467044 100644
--- a/drivers/firmware/dmi-id.c
+++ b/drivers/firmware/dmi-id.c
@@ -58,6 +58,46 @@ DEFINE_DMI_ATTR_WITH_SHOW(chassis_version, 0444, DMI_CHASSIS_VERSION);
DEFINE_DMI_ATTR_WITH_SHOW(chassis_serial, 0400, DMI_CHASSIS_SERIAL);
DEFINE_DMI_ATTR_WITH_SHOW(chassis_asset_tag, 0444, DMI_CHASSIS_ASSET_TAG);
+#ifdef CONFIG_DMIID_OEM_STRINGS
+static struct attribute *dmi_oem_attrs[] = {
+ NULL,
+};
+
+static const char oem_group[] = "oem";
+
+static struct attribute_group dmi_oem_attr_group = {
+ .attrs = dmi_oem_attrs,
+ .name = oem_group,
+};
+
+static LIST_HEAD(dmi_oem_attrs_list);
+
+struct dmi_oem_attribute {
+ struct device_attribute dev_attr;
+ const char *oem_string;
+ char buf[32];
+ bool is_added:1;
+ struct list_head list;
+};
+
+#define to_dmi_oem_attr(_dev_attr) \
+ container_of(_dev_attr, struct dmi_oem_attribute, dev_attr)
+
+static ssize_t sys_dmi_oem_show(struct device *dev,
+ struct device_attribute *attr,
+ char *page)
+{
+ struct dmi_oem_attribute *oa = to_dmi_oem_attr(attr);
+ ssize_t len;
+
+ strlcpy(page, oa->oem_string, PAGE_SIZE-1);
+ len = strlen(page);
+ page[len++] = '\n';
+ page[len] = 0;
+ return len;
+}
+#endif
+
static void ascii_filter(char *d, const char *s)
{
/* Filter out characters we don't want to see in the modalias string */
@@ -204,6 +244,72 @@ static void __init dmi_id_init_attr_table(void)
sys_dmi_attributes[i++] = &sys_dmi_modalias_attr.attr;
}
+#ifdef CONFIG_DMIID_OEM_STRINGS
+static int __init dmi_id_init_oem_attr_group(void)
+{
+ int i, ret;
+ const struct dmi_device *dev;
+ struct dmi_oem_attribute *oa, *tmp;
+ struct device_attribute dev_attr_tmpl =
+ __ATTR(, 0444, sys_dmi_oem_show, NULL);
+
+ ret = sysfs_create_group(&dmi_dev->kobj, &dmi_oem_attr_group);
+ if (ret)
+ return ret;
+
+ /* All devices with type=DMI_DEV_TYPE_OEM_STRING will be found in
+ * the reverse order of what they were parsed in dmi_scan.c. However,
+ * we do want to expose the OEM strings to sysfs in the same order as
+ * what they were originally parsed. A linked list with 2-pass method
+ * is used here to reverse the reserved order.
+ *
+ * Pass 1: find out all "OEM string" devices and add each "oem string"
+ * to a linked list.
+ */
+ dev = dmi_find_device(DMI_DEV_TYPE_OEM_STRING, NULL, NULL);
+ while (dev) {
+ oa = kzalloc(sizeof(*oa), GFP_KERNEL);
+ if (!oa) {
+ ret = -ENOMEM;
+ goto failed;
+ }
+ oa->dev_attr = dev_attr_tmpl;
+ oa->oem_string = dev->name;
+ list_add(&oa->list, &dmi_oem_attrs_list);
+ dev = dmi_find_device(DMI_DEV_TYPE_OEM_STRING, NULL, dev);
+ }
+
+ /* Pass 2: traverse the list and add each string as a file to "oem"
+ * group
+ */
+ i = 0;
+ list_for_each_entry(oa, &dmi_oem_attrs_list, list) {
+ snprintf(oa->buf, sizeof(oa->buf), "string%d", ++i);
+ oa->dev_attr.attr.name = oa->buf;
+ oa->dev_attr.attr.mode = 0400;
+ ret = sysfs_add_file_to_group(
+ &dmi_dev->kobj, &oa->dev_attr.attr, oem_group);
+ if (ret)
+ goto failed;
+ oa->is_added = 1;
+ }
+
+ return 0;
+
+failed:
+ list_for_each_entry_safe(oa, tmp, &dmi_oem_attrs_list, list) {
+ if (oa->is_added)
+ sysfs_remove_file_from_group(
+ &dmi_dev->kobj, &oa->dev_attr.attr, oem_group);
+ list_del(&oa->list);
+ kfree(oa);
+ }
+ sysfs_remove_group(&dmi_dev->kobj, &dmi_oem_attr_group);
+
+ return ret;
+}
+#endif
+
static int __init dmi_id_init(void)
{
int ret;
@@ -231,8 +337,18 @@ static int __init dmi_id_init(void)
if (ret)
goto fail_put_dmi_dev;
+#ifdef CONFIG_DMIID_OEM_STRINGS
+ ret = dmi_id_init_oem_attr_group();
+ if (ret)
+ goto fail_dev_unregister;
+#endif
return 0;
+#ifdef CONFIG_DMIID_OEM_STRINGS
+fail_dev_unregister:
+ device_unregister(dmi_dev);
+#endif
+
fail_put_dmi_dev:
put_device(dmi_dev);
--
2.7.4
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