diff options
Diffstat (limited to 'drivers/firmware/dmi-sysfs.c')
| -rw-r--r-- | drivers/firmware/dmi-sysfs.c | 696 |
1 files changed, 696 insertions, 0 deletions
diff --git a/drivers/firmware/dmi-sysfs.c b/drivers/firmware/dmi-sysfs.c new file mode 100644 index 00000000..eb26d62e --- /dev/null +++ b/drivers/firmware/dmi-sysfs.c @@ -0,0 +1,696 @@ +/* + * 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> + +#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 = ioremap(sel->access_method_address, sel->area_length); + if (!mapped) + return -EIO; + + while (count && pos < sel->area_length) { + count--; + *(buf++) = readb(mapped + pos++); + wrote++; + } + + iounmap(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); + sysfs_remove_bin_file(&entry->kobj, &dmi_entry_raw_attr); + 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 kobject *dmi_kobj; +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) { + kfree(entry); + 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 = -ENOMEM; + int val; + + /* Set up our directory */ + dmi_kobj = kobject_create_and_add("dmi", firmware_kobj); + if (!dmi_kobj) + goto err; + + dmi_kset = kset_create_and_add("entries", NULL, dmi_kobj); + if (!dmi_kset) + 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); + kobject_put(dmi_kobj); + 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); + kobject_put(dmi_kobj); +} + +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"); |