There are situations when code needs to access SMBIOS entry table area, but cannot use /dev/mem for this. As the table format is consistent only for a version, and can be changed, use binary attribute to give access to raw SMBIOS entry table area.
Signed-off-by: Ivan Khoronzhuk ivan.khoronzhuk@linaro.org --- drivers/firmware/dmi-sysfs.c | 42 ++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 42 insertions(+)
diff --git a/drivers/firmware/dmi-sysfs.c b/drivers/firmware/dmi-sysfs.c index e0f1cb3..b5c0558 100644 --- a/drivers/firmware/dmi-sysfs.c +++ b/drivers/firmware/dmi-sysfs.c @@ -46,6 +46,8 @@ struct dmi_sysfs_entry { static LIST_HEAD(entry_list); static DEFINE_SPINLOCK(entry_list_lock);
+static unsigned char smbios_raw_header[32]; + /* dmi_sysfs_attribute - Top level attribute. used by all entries. */ struct dmi_sysfs_attribute { struct attribute attr; @@ -646,9 +648,37 @@ static void cleanup_entry_list(void) } }
+static ssize_t smbios_entry_area_raw_read(struct file *filp, + struct kobject *kobj, + struct bin_attribute *bin_attr, + char *buf, loff_t pos, size_t count) +{ + ssize_t size; + + size = bin_attr->size; + + if (size > pos) + size -= pos; + else + return 0; + + if (count < size) + size = count; + + memcpy(buf, &smbios_raw_header[pos], size); + + return size; +} + +static struct bin_attribute smbios_entry_area_raw_attr = { + .read = smbios_entry_area_raw_read, + .attr = {.name = "smbios_raw_header", .mode = 0400}, +}; + static int __init dmi_sysfs_init(void) { int error = -ENOMEM; + int size; int val;
/* Set up our directory */ @@ -669,6 +699,18 @@ static int __init dmi_sysfs_init(void) goto err; }
+ size = dmi_get_smbios_entry_area(smbios_raw_header); + if (size == -ENODATA) { + pr_debug("dmi-sysfs: SMBIOS raw data is not available.\n"); + error = size; + goto err; + } + + /* Create the raw binary file to access the entry area */ + smbios_entry_area_raw_attr.size = size; + if (sysfs_create_bin_file(dmi_kobj, &smbios_entry_area_raw_attr)) + goto err; + pr_debug("dmi-sysfs: loaded.\n");
return 0;