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320 lines
6.7 KiB
320 lines
6.7 KiB
// SPDX-License-Identifier: GPL-2.0-only |
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/* |
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* vpd.c |
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* |
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* Driver for exporting VPD content to sysfs. |
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* |
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* Copyright 2017 Google Inc. |
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*/ |
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#include <linux/ctype.h> |
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#include <linux/init.h> |
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#include <linux/io.h> |
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#include <linux/kernel.h> |
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#include <linux/kobject.h> |
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#include <linux/list.h> |
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#include <linux/module.h> |
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#include <linux/of_address.h> |
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#include <linux/platform_device.h> |
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#include <linux/slab.h> |
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#include <linux/sysfs.h> |
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#include "coreboot_table.h" |
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#include "vpd_decode.h" |
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#define CB_TAG_VPD 0x2c |
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#define VPD_CBMEM_MAGIC 0x43524f53 |
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static struct kobject *vpd_kobj; |
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struct vpd_cbmem { |
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u32 magic; |
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u32 version; |
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u32 ro_size; |
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u32 rw_size; |
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u8 blob[]; |
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}; |
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struct vpd_section { |
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bool enabled; |
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const char *name; |
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char *raw_name; /* the string name_raw */ |
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struct kobject *kobj; /* vpd/name directory */ |
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char *baseaddr; |
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struct bin_attribute bin_attr; /* vpd/name_raw bin_attribute */ |
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struct list_head attribs; /* key/value in vpd_attrib_info list */ |
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}; |
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struct vpd_attrib_info { |
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char *key; |
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const char *value; |
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struct bin_attribute bin_attr; |
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struct list_head list; |
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}; |
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static struct vpd_section ro_vpd; |
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static struct vpd_section rw_vpd; |
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static ssize_t vpd_attrib_read(struct file *filp, struct kobject *kobp, |
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struct bin_attribute *bin_attr, char *buf, |
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loff_t pos, size_t count) |
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{ |
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struct vpd_attrib_info *info = bin_attr->private; |
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return memory_read_from_buffer(buf, count, &pos, info->value, |
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info->bin_attr.size); |
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} |
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/* |
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* vpd_section_check_key_name() |
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* |
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* The VPD specification supports only [a-zA-Z0-9_]+ characters in key names but |
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* old firmware versions may have entries like "S/N" which are problematic when |
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* exporting them as sysfs attributes. These keys present in old firmwares are |
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* ignored. |
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* |
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* Returns VPD_OK for a valid key name, VPD_FAIL otherwise. |
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* |
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* @key: The key name to check |
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* @key_len: key name length |
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*/ |
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static int vpd_section_check_key_name(const u8 *key, s32 key_len) |
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{ |
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int c; |
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while (key_len-- > 0) { |
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c = *key++; |
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if (!isalnum(c) && c != '_') |
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return VPD_FAIL; |
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} |
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return VPD_OK; |
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} |
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static int vpd_section_attrib_add(const u8 *key, u32 key_len, |
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const u8 *value, u32 value_len, |
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void *arg) |
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{ |
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int ret; |
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struct vpd_section *sec = arg; |
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struct vpd_attrib_info *info; |
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/* |
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* Return VPD_OK immediately to decode next entry if the current key |
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* name contains invalid characters. |
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*/ |
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if (vpd_section_check_key_name(key, key_len) != VPD_OK) |
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return VPD_OK; |
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info = kzalloc(sizeof(*info), GFP_KERNEL); |
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if (!info) |
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return -ENOMEM; |
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info->key = kstrndup(key, key_len, GFP_KERNEL); |
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if (!info->key) { |
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ret = -ENOMEM; |
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goto free_info; |
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} |
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sysfs_bin_attr_init(&info->bin_attr); |
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info->bin_attr.attr.name = info->key; |
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info->bin_attr.attr.mode = 0444; |
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info->bin_attr.size = value_len; |
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info->bin_attr.read = vpd_attrib_read; |
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info->bin_attr.private = info; |
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info->value = value; |
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INIT_LIST_HEAD(&info->list); |
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ret = sysfs_create_bin_file(sec->kobj, &info->bin_attr); |
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if (ret) |
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goto free_info_key; |
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list_add_tail(&info->list, &sec->attribs); |
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return 0; |
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free_info_key: |
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kfree(info->key); |
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free_info: |
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kfree(info); |
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return ret; |
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} |
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static void vpd_section_attrib_destroy(struct vpd_section *sec) |
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{ |
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struct vpd_attrib_info *info; |
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struct vpd_attrib_info *temp; |
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list_for_each_entry_safe(info, temp, &sec->attribs, list) { |
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sysfs_remove_bin_file(sec->kobj, &info->bin_attr); |
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kfree(info->key); |
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kfree(info); |
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} |
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} |
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static ssize_t vpd_section_read(struct file *filp, struct kobject *kobp, |
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struct bin_attribute *bin_attr, char *buf, |
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loff_t pos, size_t count) |
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{ |
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struct vpd_section *sec = bin_attr->private; |
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return memory_read_from_buffer(buf, count, &pos, sec->baseaddr, |
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sec->bin_attr.size); |
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} |
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static int vpd_section_create_attribs(struct vpd_section *sec) |
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{ |
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s32 consumed; |
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int ret; |
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consumed = 0; |
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do { |
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ret = vpd_decode_string(sec->bin_attr.size, sec->baseaddr, |
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&consumed, vpd_section_attrib_add, sec); |
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} while (ret == VPD_OK); |
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return 0; |
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} |
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static int vpd_section_init(const char *name, struct vpd_section *sec, |
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phys_addr_t physaddr, size_t size) |
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{ |
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int err; |
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sec->baseaddr = memremap(physaddr, size, MEMREMAP_WB); |
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if (!sec->baseaddr) |
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return -ENOMEM; |
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sec->name = name; |
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/* We want to export the raw partition with name ${name}_raw */ |
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sec->raw_name = kasprintf(GFP_KERNEL, "%s_raw", name); |
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if (!sec->raw_name) { |
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err = -ENOMEM; |
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goto err_memunmap; |
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} |
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sysfs_bin_attr_init(&sec->bin_attr); |
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sec->bin_attr.attr.name = sec->raw_name; |
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sec->bin_attr.attr.mode = 0444; |
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sec->bin_attr.size = size; |
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sec->bin_attr.read = vpd_section_read; |
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sec->bin_attr.private = sec; |
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err = sysfs_create_bin_file(vpd_kobj, &sec->bin_attr); |
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if (err) |
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goto err_free_raw_name; |
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sec->kobj = kobject_create_and_add(name, vpd_kobj); |
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if (!sec->kobj) { |
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err = -EINVAL; |
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goto err_sysfs_remove; |
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} |
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INIT_LIST_HEAD(&sec->attribs); |
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vpd_section_create_attribs(sec); |
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sec->enabled = true; |
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return 0; |
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err_sysfs_remove: |
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sysfs_remove_bin_file(vpd_kobj, &sec->bin_attr); |
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err_free_raw_name: |
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kfree(sec->raw_name); |
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err_memunmap: |
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memunmap(sec->baseaddr); |
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return err; |
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} |
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static int vpd_section_destroy(struct vpd_section *sec) |
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{ |
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if (sec->enabled) { |
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vpd_section_attrib_destroy(sec); |
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kobject_put(sec->kobj); |
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sysfs_remove_bin_file(vpd_kobj, &sec->bin_attr); |
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kfree(sec->raw_name); |
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memunmap(sec->baseaddr); |
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sec->enabled = false; |
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} |
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return 0; |
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} |
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static int vpd_sections_init(phys_addr_t physaddr) |
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{ |
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struct vpd_cbmem *temp; |
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struct vpd_cbmem header; |
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int ret = 0; |
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temp = memremap(physaddr, sizeof(struct vpd_cbmem), MEMREMAP_WB); |
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if (!temp) |
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return -ENOMEM; |
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memcpy(&header, temp, sizeof(struct vpd_cbmem)); |
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memunmap(temp); |
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if (header.magic != VPD_CBMEM_MAGIC) |
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return -ENODEV; |
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if (header.ro_size) { |
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ret = vpd_section_init("ro", &ro_vpd, |
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physaddr + sizeof(struct vpd_cbmem), |
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header.ro_size); |
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if (ret) |
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return ret; |
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} |
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if (header.rw_size) { |
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ret = vpd_section_init("rw", &rw_vpd, |
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physaddr + sizeof(struct vpd_cbmem) + |
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header.ro_size, header.rw_size); |
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if (ret) { |
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vpd_section_destroy(&ro_vpd); |
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return ret; |
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} |
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} |
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return 0; |
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} |
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static int vpd_probe(struct coreboot_device *dev) |
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{ |
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int ret; |
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vpd_kobj = kobject_create_and_add("vpd", firmware_kobj); |
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if (!vpd_kobj) |
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return -ENOMEM; |
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ret = vpd_sections_init(dev->cbmem_ref.cbmem_addr); |
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if (ret) { |
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kobject_put(vpd_kobj); |
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return ret; |
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} |
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return 0; |
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} |
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static void vpd_remove(struct coreboot_device *dev) |
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{ |
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vpd_section_destroy(&ro_vpd); |
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vpd_section_destroy(&rw_vpd); |
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kobject_put(vpd_kobj); |
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} |
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static struct coreboot_driver vpd_driver = { |
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.probe = vpd_probe, |
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.remove = vpd_remove, |
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.drv = { |
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.name = "vpd", |
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}, |
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.tag = CB_TAG_VPD, |
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}; |
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module_coreboot_driver(vpd_driver); |
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MODULE_AUTHOR("Google, Inc."); |
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MODULE_LICENSE("GPL");
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