1 files changed, 697 insertions, 0 deletions

diff --git a/drivers/firmware/dmi-sysfs.c b/drivers/firmware/dmi-sysfs.c
new file mode 100644
index 000000000..5d6b497d5
--- /dev/null
+++ b/drivers/firmware/dmi-sysfs.c
@@ -0,0 +1,697 @@
+/*
+ * dmi-sysfs.c
+ *
+ * This module exports the DMI tables read-only to userspace through the
+ * sysfs file system.
+ *
+ * Data is currently found below
+ *    /sys/firmware/dmi/...
+ *
+ * DMI attributes are presented in attribute files with names
+ * formatted using %d-%d, so that the first integer indicates the
+ * structure type (0-255), and the second field is the instance of that
+ * entry.
+ *
+ * Copyright 2011 Google, Inc.
+ */
+
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/types.h>
+#include <linux/kobject.h>
+#include <linux/dmi.h>
+#include <linux/capability.h>
+#include <linux/slab.h>
+#include <linux/list.h>
+#include <linux/io.h>
+#include <asm/dmi.h>
+
+#define MAX_ENTRY_TYPE 255 /* Most of these aren't used, but we consider
+			      the top entry type is only 8 bits */
+
+struct dmi_sysfs_entry {
+	struct dmi_header dh;
+	struct kobject kobj;
+	int instance;
+	int position;
+	struct list_head list;
+	struct kobject *child;
+};
+
+/*
+ * Global list of dmi_sysfs_entry.  Even though this should only be
+ * manipulated at setup and teardown, the lazy nature of the kobject
+ * system means we get lazy removes.
+ */
+static LIST_HEAD(entry_list);
+static DEFINE_SPINLOCK(entry_list_lock);
+
+/* dmi_sysfs_attribute - Top level attribute. used by all entries. */
+struct dmi_sysfs_attribute {
+	struct attribute attr;
+	ssize_t (*show)(struct dmi_sysfs_entry *entry, char *buf);
+};
+
+#define DMI_SYSFS_ATTR(_entry, _name) \
+struct dmi_sysfs_attribute dmi_sysfs_attr_##_entry##_##_name = { \
+	.attr = {.name = __stringify(_name), .mode = 0400}, \
+	.show = dmi_sysfs_##_entry##_##_name, \
+}
+
+/*
+ * dmi_sysfs_mapped_attribute - Attribute where we require the entry be
+ * mapped in.  Use in conjunction with dmi_sysfs_specialize_attr_ops.
+ */
+struct dmi_sysfs_mapped_attribute {
+	struct attribute attr;
+	ssize_t (*show)(struct dmi_sysfs_entry *entry,
+			const struct dmi_header *dh,
+			char *buf);
+};
+
+#define DMI_SYSFS_MAPPED_ATTR(_entry, _name) \
+struct dmi_sysfs_mapped_attribute dmi_sysfs_attr_##_entry##_##_name = { \
+	.attr = {.name = __stringify(_name), .mode = 0400}, \
+	.show = dmi_sysfs_##_entry##_##_name, \
+}
+
+/*************************************************
+ * Generic DMI entry support.
+ *************************************************/
+static void dmi_entry_free(struct kobject *kobj)
+{
+	kfree(kobj);
+}
+
+static struct dmi_sysfs_entry *to_entry(struct kobject *kobj)
+{
+	return container_of(kobj, struct dmi_sysfs_entry, kobj);
+}
+
+static struct dmi_sysfs_attribute *to_attr(struct attribute *attr)
+{
+	return container_of(attr, struct dmi_sysfs_attribute, attr);
+}
+
+static ssize_t dmi_sysfs_attr_show(struct kobject *kobj,
+				   struct attribute *_attr, char *buf)
+{
+	struct dmi_sysfs_entry *entry = to_entry(kobj);
+	struct dmi_sysfs_attribute *attr = to_attr(_attr);
+
+	/* DMI stuff is only ever admin visible */
+	if (!capable(CAP_SYS_ADMIN))
+		return -EACCES;
+
+	return attr->show(entry, buf);
+}
+
+static const struct sysfs_ops dmi_sysfs_attr_ops = {
+	.show = dmi_sysfs_attr_show,
+};
+
+typedef ssize_t (*dmi_callback)(struct dmi_sysfs_entry *,
+				const struct dmi_header *dh, void *);
+
+struct find_dmi_data {
+	struct dmi_sysfs_entry	*entry;
+	dmi_callback		callback;
+	void			*private;
+	int			instance_countdown;
+	ssize_t			ret;
+};
+
+static void find_dmi_entry_helper(const struct dmi_header *dh,
+				  void *_data)
+{
+	struct find_dmi_data *data = _data;
+	struct dmi_sysfs_entry *entry = data->entry;
+
+	/* Is this the entry we want? */
+	if (dh->type != entry->dh.type)
+		return;
+
+	if (data->instance_countdown != 0) {
+		/* try the next instance? */
+		data->instance_countdown--;
+		return;
+	}
+
+	/*
+	 * Don't ever revisit the instance.  Short circuit later
+	 * instances by letting the instance_countdown run negative
+	 */
+	data->instance_countdown--;
+
+	/* Found the entry */
+	data->ret = data->callback(entry, dh, data->private);
+}
+
+/* State for passing the read parameters through dmi_find_entry() */
+struct dmi_read_state {
+	char *buf;
+	loff_t pos;
+	size_t count;
+};
+
+static ssize_t find_dmi_entry(struct dmi_sysfs_entry *entry,
+			      dmi_callback callback, void *private)
+{
+	struct find_dmi_data data = {
+		.entry = entry,
+		.callback = callback,
+		.private = private,
+		.instance_countdown = entry->instance,
+		.ret = -EIO,  /* To signal the entry disappeared */
+	};
+	int ret;
+
+	ret = dmi_walk(find_dmi_entry_helper, &data);
+	/* This shouldn't happen, but just in case. */
+	if (ret)
+		return -EINVAL;
+	return data.ret;
+}
+
+/*
+ * Calculate and return the byte length of the dmi entry identified by
+ * dh.  This includes both the formatted portion as well as the
+ * unformatted string space, including the two trailing nul characters.
+ */
+static size_t dmi_entry_length(const struct dmi_header *dh)
+{
+	const char *p = (const char *)dh;
+
+	p += dh->length;
+
+	while (p[0] || p[1])
+		p++;
+
+	return 2 + p - (const char *)dh;
+}
+
+/*************************************************
+ * Support bits for specialized DMI entry support
+ *************************************************/
+struct dmi_entry_attr_show_data {
+	struct attribute *attr;
+	char *buf;
+};
+
+static ssize_t dmi_entry_attr_show_helper(struct dmi_sysfs_entry *entry,
+					  const struct dmi_header *dh,
+					  void *_data)
+{
+	struct dmi_entry_attr_show_data *data = _data;
+	struct dmi_sysfs_mapped_attribute *attr;
+
+	attr = container_of(data->attr,
+			    struct dmi_sysfs_mapped_attribute, attr);
+	return attr->show(entry, dh, data->buf);
+}
+
+static ssize_t dmi_entry_attr_show(struct kobject *kobj,
+				   struct attribute *attr,
+				   char *buf)
+{
+	struct dmi_entry_attr_show_data data = {
+		.attr = attr,
+		.buf  = buf,
+	};
+	/* Find the entry according to our parent and call the
+	 * normalized show method hanging off of the attribute */
+	return find_dmi_entry(to_entry(kobj->parent),
+			      dmi_entry_attr_show_helper, &data);
+}
+
+static const struct sysfs_ops dmi_sysfs_specialize_attr_ops = {
+	.show = dmi_entry_attr_show,
+};
+
+/*************************************************
+ * Specialized DMI entry support.
+ *************************************************/
+
+/*** Type 15 - System Event Table ***/
+
+#define DMI_SEL_ACCESS_METHOD_IO8	0x00
+#define DMI_SEL_ACCESS_METHOD_IO2x8	0x01
+#define DMI_SEL_ACCESS_METHOD_IO16	0x02
+#define DMI_SEL_ACCESS_METHOD_PHYS32	0x03
+#define DMI_SEL_ACCESS_METHOD_GPNV	0x04
+
+struct dmi_system_event_log {
+	struct dmi_header header;
+	u16	area_length;
+	u16	header_start_offset;
+	u16	data_start_offset;
+	u8	access_method;
+	u8	status;
+	u32	change_token;
+	union {
+		struct {
+			u16 index_addr;
+			u16 data_addr;
+		} io;
+		u32	phys_addr32;
+		u16	gpnv_handle;
+		u32	access_method_address;
+	};
+	u8	header_format;
+	u8	type_descriptors_supported_count;
+	u8	per_log_type_descriptor_length;
+	u8	supported_log_type_descriptos[0];
+} __packed;
+
+#define DMI_SYSFS_SEL_FIELD(_field) \
+static ssize_t dmi_sysfs_sel_##_field(struct dmi_sysfs_entry *entry, \
+				      const struct dmi_header *dh, \
+				      char *buf) \
+{ \
+	struct dmi_system_event_log sel; \
+	if (sizeof(sel) > dmi_entry_length(dh)) \
+		return -EIO; \
+	memcpy(&sel, dh, sizeof(sel)); \
+	return sprintf(buf, "%u\n", sel._field); \
+} \
+static DMI_SYSFS_MAPPED_ATTR(sel, _field)
+
+DMI_SYSFS_SEL_FIELD(area_length);
+DMI_SYSFS_SEL_FIELD(header_start_offset);
+DMI_SYSFS_SEL_FIELD(data_start_offset);
+DMI_SYSFS_SEL_FIELD(access_method);
+DMI_SYSFS_SEL_FIELD(status);
+DMI_SYSFS_SEL_FIELD(change_token);
+DMI_SYSFS_SEL_FIELD(access_method_address);
+DMI_SYSFS_SEL_FIELD(header_format);
+DMI_SYSFS_SEL_FIELD(type_descriptors_supported_count);
+DMI_SYSFS_SEL_FIELD(per_log_type_descriptor_length);
+
+static struct attribute *dmi_sysfs_sel_attrs[] = {
+	&dmi_sysfs_attr_sel_area_length.attr,
+	&dmi_sysfs_attr_sel_header_start_offset.attr,
+	&dmi_sysfs_attr_sel_data_start_offset.attr,
+	&dmi_sysfs_attr_sel_access_method.attr,
+	&dmi_sysfs_attr_sel_status.attr,
+	&dmi_sysfs_attr_sel_change_token.attr,
+	&dmi_sysfs_attr_sel_access_method_address.attr,
+	&dmi_sysfs_attr_sel_header_format.attr,
+	&dmi_sysfs_attr_sel_type_descriptors_supported_count.attr,
+	&dmi_sysfs_attr_sel_per_log_type_descriptor_length.attr,
+	NULL,
+};
+
+
+static struct kobj_type dmi_system_event_log_ktype = {
+	.release = dmi_entry_free,
+	.sysfs_ops = &dmi_sysfs_specialize_attr_ops,
+	.default_attrs = dmi_sysfs_sel_attrs,
+};
+
+typedef u8 (*sel_io_reader)(const struct dmi_system_event_log *sel,
+			    loff_t offset);
+
+static DEFINE_MUTEX(io_port_lock);
+
+static u8 read_sel_8bit_indexed_io(const struct dmi_system_event_log *sel,
+				   loff_t offset)
+{
+	u8 ret;
+
+	mutex_lock(&io_port_lock);
+	outb((u8)offset, sel->io.index_addr);
+	ret = inb(sel->io.data_addr);
+	mutex_unlock(&io_port_lock);
+	return ret;
+}
+
+static u8 read_sel_2x8bit_indexed_io(const struct dmi_system_event_log *sel,
+				     loff_t offset)
+{
+	u8 ret;
+
+	mutex_lock(&io_port_lock);
+	outb((u8)offset, sel->io.index_addr);
+	outb((u8)(offset >> 8), sel->io.index_addr + 1);
+	ret = inb(sel->io.data_addr);
+	mutex_unlock(&io_port_lock);
+	return ret;
+}
+
+static u8 read_sel_16bit_indexed_io(const struct dmi_system_event_log *sel,
+				    loff_t offset)
+{
+	u8 ret;
+
+	mutex_lock(&io_port_lock);
+	outw((u16)offset, sel->io.index_addr);
+	ret = inb(sel->io.data_addr);
+	mutex_unlock(&io_port_lock);
+	return ret;
+}
+
+static sel_io_reader sel_io_readers[] = {
+	[DMI_SEL_ACCESS_METHOD_IO8]	= read_sel_8bit_indexed_io,
+	[DMI_SEL_ACCESS_METHOD_IO2x8]	= read_sel_2x8bit_indexed_io,
+	[DMI_SEL_ACCESS_METHOD_IO16]	= read_sel_16bit_indexed_io,
+};
+
+static ssize_t dmi_sel_raw_read_io(struct dmi_sysfs_entry *entry,
+				   const struct dmi_system_event_log *sel,
+				   char *buf, loff_t pos, size_t count)
+{
+	ssize_t wrote = 0;
+
+	sel_io_reader io_reader = sel_io_readers[sel->access_method];
+
+	while (count && pos < sel->area_length) {
+		count--;
+		*(buf++) = io_reader(sel, pos++);
+		wrote++;
+	}
+
+	return wrote;
+}
+
+static ssize_t dmi_sel_raw_read_phys32(struct dmi_sysfs_entry *entry,
+				       const struct dmi_system_event_log *sel,
+				       char *buf, loff_t pos, size_t count)
+{
+	u8 __iomem *mapped;
+	ssize_t wrote = 0;
+
+	mapped = dmi_remap(sel->access_method_address, sel->area_length);
+	if (!mapped)
+		return -EIO;
+
+	while (count && pos < sel->area_length) {
+		count--;
+		*(buf++) = readb(mapped + pos++);
+		wrote++;
+	}
+
+	dmi_unmap(mapped);
+	return wrote;
+}
+
+static ssize_t dmi_sel_raw_read_helper(struct dmi_sysfs_entry *entry,
+				       const struct dmi_header *dh,
+				       void *_state)
+{
+	struct dmi_read_state *state = _state;
+	struct dmi_system_event_log sel;
+
+	if (sizeof(sel) > dmi_entry_length(dh))
+		return -EIO;
+
+	memcpy(&sel, dh, sizeof(sel));
+
+	switch (sel.access_method) {
+	case DMI_SEL_ACCESS_METHOD_IO8:
+	case DMI_SEL_ACCESS_METHOD_IO2x8:
+	case DMI_SEL_ACCESS_METHOD_IO16:
+		return dmi_sel_raw_read_io(entry, &sel, state->buf,
+					   state->pos, state->count);
+	case DMI_SEL_ACCESS_METHOD_PHYS32:
+		return dmi_sel_raw_read_phys32(entry, &sel, state->buf,
+					       state->pos, state->count);
+	case DMI_SEL_ACCESS_METHOD_GPNV:
+		pr_info("dmi-sysfs: GPNV support missing.\n");
+		return -EIO;
+	default:
+		pr_info("dmi-sysfs: Unknown access method %02x\n",
+			sel.access_method);
+		return -EIO;
+	}
+}
+
+static ssize_t dmi_sel_raw_read(struct file *filp, struct kobject *kobj,
+				struct bin_attribute *bin_attr,
+				char *buf, loff_t pos, size_t count)
+{
+	struct dmi_sysfs_entry *entry = to_entry(kobj->parent);
+	struct dmi_read_state state = {
+		.buf = buf,
+		.pos = pos,
+		.count = count,
+	};
+
+	return find_dmi_entry(entry, dmi_sel_raw_read_helper, &state);
+}
+
+static struct bin_attribute dmi_sel_raw_attr = {
+	.attr = {.name = "raw_event_log", .mode = 0400},
+	.read = dmi_sel_raw_read,
+};
+
+static int dmi_system_event_log(struct dmi_sysfs_entry *entry)
+{
+	int ret;
+
+	entry->child = kzalloc(sizeof(*entry->child), GFP_KERNEL);
+	if (!entry->child)
+		return -ENOMEM;
+	ret = kobject_init_and_add(entry->child,
+				   &dmi_system_event_log_ktype,
+				   &entry->kobj,
+				   "system_event_log");
+	if (ret)
+		goto out_free;
+
+	ret = sysfs_create_bin_file(entry->child, &dmi_sel_raw_attr);
+	if (ret)
+		goto out_del;
+
+	return 0;
+
+out_del:
+	kobject_del(entry->child);
+out_free:
+	kfree(entry->child);
+	return ret;
+}
+
+/*************************************************
+ * Generic DMI entry support.
+ *************************************************/
+
+static ssize_t dmi_sysfs_entry_length(struct dmi_sysfs_entry *entry, char *buf)
+{
+	return sprintf(buf, "%d\n", entry->dh.length);
+}
+
+static ssize_t dmi_sysfs_entry_handle(struct dmi_sysfs_entry *entry, char *buf)
+{
+	return sprintf(buf, "%d\n", entry->dh.handle);
+}
+
+static ssize_t dmi_sysfs_entry_type(struct dmi_sysfs_entry *entry, char *buf)
+{
+	return sprintf(buf, "%d\n", entry->dh.type);
+}
+
+static ssize_t dmi_sysfs_entry_instance(struct dmi_sysfs_entry *entry,
+					char *buf)
+{
+	return sprintf(buf, "%d\n", entry->instance);
+}
+
+static ssize_t dmi_sysfs_entry_position(struct dmi_sysfs_entry *entry,
+					char *buf)
+{
+	return sprintf(buf, "%d\n", entry->position);
+}
+
+static DMI_SYSFS_ATTR(entry, length);
+static DMI_SYSFS_ATTR(entry, handle);
+static DMI_SYSFS_ATTR(entry, type);
+static DMI_SYSFS_ATTR(entry, instance);
+static DMI_SYSFS_ATTR(entry, position);
+
+static struct attribute *dmi_sysfs_entry_attrs[] = {
+	&dmi_sysfs_attr_entry_length.attr,
+	&dmi_sysfs_attr_entry_handle.attr,
+	&dmi_sysfs_attr_entry_type.attr,
+	&dmi_sysfs_attr_entry_instance.attr,
+	&dmi_sysfs_attr_entry_position.attr,
+	NULL,
+};
+
+static ssize_t dmi_entry_raw_read_helper(struct dmi_sysfs_entry *entry,
+					 const struct dmi_header *dh,
+					 void *_state)
+{
+	struct dmi_read_state *state = _state;
+	size_t entry_length;
+
+	entry_length = dmi_entry_length(dh);
+
+	return memory_read_from_buffer(state->buf, state->count,
+				       &state->pos, dh, entry_length);
+}
+
+static ssize_t dmi_entry_raw_read(struct file *filp,
+				  struct kobject *kobj,
+				  struct bin_attribute *bin_attr,
+				  char *buf, loff_t pos, size_t count)
+{
+	struct dmi_sysfs_entry *entry = to_entry(kobj);
+	struct dmi_read_state state = {
+		.buf = buf,
+		.pos = pos,
+		.count = count,
+	};
+
+	return find_dmi_entry(entry, dmi_entry_raw_read_helper, &state);
+}
+
+static const struct bin_attribute dmi_entry_raw_attr = {
+	.attr = {.name = "raw", .mode = 0400},
+	.read = dmi_entry_raw_read,
+};
+
+static void dmi_sysfs_entry_release(struct kobject *kobj)
+{
+	struct dmi_sysfs_entry *entry = to_entry(kobj);
+
+	spin_lock(&entry_list_lock);
+	list_del(&entry->list);
+	spin_unlock(&entry_list_lock);
+	kfree(entry);
+}
+
+static struct kobj_type dmi_sysfs_entry_ktype = {
+	.release = dmi_sysfs_entry_release,
+	.sysfs_ops = &dmi_sysfs_attr_ops,
+	.default_attrs = dmi_sysfs_entry_attrs,
+};
+
+static struct kset *dmi_kset;
+
+/* Global count of all instances seen.  Only for setup */
+static int __initdata instance_counts[MAX_ENTRY_TYPE + 1];
+
+/* Global positional count of all entries seen.  Only for setup */
+static int __initdata position_count;
+
+static void __init dmi_sysfs_register_handle(const struct dmi_header *dh,
+					     void *_ret)
+{
+	struct dmi_sysfs_entry *entry;
+	int *ret = _ret;
+
+	/* If a previous entry saw an error, short circuit */
+	if (*ret)
+		return;
+
+	/* Allocate and register a new entry into the entries set */
+	entry = kzalloc(sizeof(*entry), GFP_KERNEL);
+	if (!entry) {
+		*ret = -ENOMEM;
+		return;
+	}
+
+	/* Set the key */
+	memcpy(&entry->dh, dh, sizeof(*dh));
+	entry->instance = instance_counts[dh->type]++;
+	entry->position = position_count++;
+
+	entry->kobj.kset = dmi_kset;
+	*ret = kobject_init_and_add(&entry->kobj, &dmi_sysfs_entry_ktype, NULL,
+				    "%d-%d", dh->type, entry->instance);
+
+	if (*ret) {
+		kobject_put(&entry->kobj);
+		return;
+	}
+
+	/* Thread on the global list for cleanup */
+	spin_lock(&entry_list_lock);
+	list_add_tail(&entry->list, &entry_list);
+	spin_unlock(&entry_list_lock);
+
+	/* Handle specializations by type */
+	switch (dh->type) {
+	case DMI_ENTRY_SYSTEM_EVENT_LOG:
+		*ret = dmi_system_event_log(entry);
+		break;
+	default:
+		/* No specialization */
+		break;
+	}
+	if (*ret)
+		goto out_err;
+
+	/* Create the raw binary file to access the entry */
+	*ret = sysfs_create_bin_file(&entry->kobj, &dmi_entry_raw_attr);
+	if (*ret)
+		goto out_err;
+
+	return;
+out_err:
+	kobject_put(entry->child);
+	kobject_put(&entry->kobj);
+	return;
+}
+
+static void cleanup_entry_list(void)
+{
+	struct dmi_sysfs_entry *entry, *next;
+
+	/* No locks, we are on our way out */
+	list_for_each_entry_safe(entry, next, &entry_list, list) {
+		kobject_put(entry->child);
+		kobject_put(&entry->kobj);
+	}
+}
+
+static int __init dmi_sysfs_init(void)
+{
+	int error;
+	int val;
+
+	if (!dmi_kobj) {
+		pr_debug("dmi-sysfs: dmi entry is absent.\n");
+		error = -ENODATA;
+		goto err;
+	}
+
+	dmi_kset = kset_create_and_add("entries", NULL, dmi_kobj);
+	if (!dmi_kset) {
+		error = -ENOMEM;
+		goto err;
+	}
+
+	val = 0;
+	error = dmi_walk(dmi_sysfs_register_handle, &val);
+	if (error)
+		goto err;
+	if (val) {
+		error = val;
+		goto err;
+	}
+
+	pr_debug("dmi-sysfs: loaded.\n");
+
+	return 0;
+err:
+	cleanup_entry_list();
+	kset_unregister(dmi_kset);
+	return error;
+}
+
+/* clean up everything. */
+static void __exit dmi_sysfs_exit(void)
+{
+	pr_debug("dmi-sysfs: unloading.\n");
+	cleanup_entry_list();
+	kset_unregister(dmi_kset);
+}
+
+module_init(dmi_sysfs_init);
+module_exit(dmi_sysfs_exit);
+
+MODULE_AUTHOR("Mike Waychison <mikew@google.com>");
+MODULE_DESCRIPTION("DMI sysfs support");
+MODULE_LICENSE("GPL");