diff options
Diffstat (limited to '')
| -rw-r--r-- | drivers/firmware/google/vpd.c | 320 |
1 files changed, 320 insertions, 0 deletions
diff --git a/drivers/firmware/google/vpd.c b/drivers/firmware/google/vpd.c new file mode 100644 index 000000000..ee6e08c05 --- /dev/null +++ b/drivers/firmware/google/vpd.c @@ -0,0 +1,320 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * vpd.c + * + * Driver for exporting VPD content to sysfs. + * + * Copyright 2017 Google Inc. + */ + +#include <linux/ctype.h> +#include <linux/init.h> +#include <linux/io.h> +#include <linux/kernel.h> +#include <linux/kobject.h> +#include <linux/list.h> +#include <linux/module.h> +#include <linux/of_address.h> +#include <linux/platform_device.h> +#include <linux/slab.h> +#include <linux/sysfs.h> + +#include "coreboot_table.h" +#include "vpd_decode.h" + +#define CB_TAG_VPD 0x2c +#define VPD_CBMEM_MAGIC 0x43524f53 + +static struct kobject *vpd_kobj; + +struct vpd_cbmem { + u32 magic; + u32 version; + u32 ro_size; + u32 rw_size; + u8 blob[]; +}; + +struct vpd_section { + bool enabled; + const char *name; + char *raw_name; /* the string name_raw */ + struct kobject *kobj; /* vpd/name directory */ + char *baseaddr; + struct bin_attribute bin_attr; /* vpd/name_raw bin_attribute */ + struct list_head attribs; /* key/value in vpd_attrib_info list */ +}; + +struct vpd_attrib_info { + char *key; + const char *value; + struct bin_attribute bin_attr; + struct list_head list; +}; + +static struct vpd_section ro_vpd; +static struct vpd_section rw_vpd; + +static ssize_t vpd_attrib_read(struct file *filp, struct kobject *kobp, + struct bin_attribute *bin_attr, char *buf, + loff_t pos, size_t count) +{ + struct vpd_attrib_info *info = bin_attr->private; + + return memory_read_from_buffer(buf, count, &pos, info->value, + info->bin_attr.size); +} + +/* + * vpd_section_check_key_name() + * + * The VPD specification supports only [a-zA-Z0-9_]+ characters in key names but + * old firmware versions may have entries like "S/N" which are problematic when + * exporting them as sysfs attributes. These keys present in old firmwares are + * ignored. + * + * Returns VPD_OK for a valid key name, VPD_FAIL otherwise. + * + * @key: The key name to check + * @key_len: key name length + */ +static int vpd_section_check_key_name(const u8 *key, s32 key_len) +{ + int c; + + while (key_len-- > 0) { + c = *key++; + + if (!isalnum(c) && c != '_') + return VPD_FAIL; + } + + return VPD_OK; +} + +static int vpd_section_attrib_add(const u8 *key, u32 key_len, + const u8 *value, u32 value_len, + void *arg) +{ + int ret; + struct vpd_section *sec = arg; + struct vpd_attrib_info *info; + + /* + * Return VPD_OK immediately to decode next entry if the current key + * name contains invalid characters. + */ + if (vpd_section_check_key_name(key, key_len) != VPD_OK) + return VPD_OK; + + info = kzalloc(sizeof(*info), GFP_KERNEL); + if (!info) + return -ENOMEM; + + info->key = kstrndup(key, key_len, GFP_KERNEL); + if (!info->key) { + ret = -ENOMEM; + goto free_info; + } + + sysfs_bin_attr_init(&info->bin_attr); + info->bin_attr.attr.name = info->key; + info->bin_attr.attr.mode = 0444; + info->bin_attr.size = value_len; + info->bin_attr.read = vpd_attrib_read; + info->bin_attr.private = info; + + info->value = value; + + INIT_LIST_HEAD(&info->list); + + ret = sysfs_create_bin_file(sec->kobj, &info->bin_attr); + if (ret) + goto free_info_key; + + list_add_tail(&info->list, &sec->attribs); + return 0; + +free_info_key: + kfree(info->key); +free_info: + kfree(info); + + return ret; +} + +static void vpd_section_attrib_destroy(struct vpd_section *sec) +{ + struct vpd_attrib_info *info; + struct vpd_attrib_info *temp; + + list_for_each_entry_safe(info, temp, &sec->attribs, list) { + sysfs_remove_bin_file(sec->kobj, &info->bin_attr); + kfree(info->key); + kfree(info); + } +} + +static ssize_t vpd_section_read(struct file *filp, struct kobject *kobp, + struct bin_attribute *bin_attr, char *buf, + loff_t pos, size_t count) +{ + struct vpd_section *sec = bin_attr->private; + + return memory_read_from_buffer(buf, count, &pos, sec->baseaddr, + sec->bin_attr.size); +} + +static int vpd_section_create_attribs(struct vpd_section *sec) +{ + s32 consumed; + int ret; + + consumed = 0; + do { + ret = vpd_decode_string(sec->bin_attr.size, sec->baseaddr, + &consumed, vpd_section_attrib_add, sec); + } while (ret == VPD_OK); + + return 0; +} + +static int vpd_section_init(const char *name, struct vpd_section *sec, + phys_addr_t physaddr, size_t size) +{ + int err; + + sec->baseaddr = memremap(physaddr, size, MEMREMAP_WB); + if (!sec->baseaddr) + return -ENOMEM; + + sec->name = name; + + /* We want to export the raw partition with name ${name}_raw */ + sec->raw_name = kasprintf(GFP_KERNEL, "%s_raw", name); + if (!sec->raw_name) { + err = -ENOMEM; + goto err_memunmap; + } + + sysfs_bin_attr_init(&sec->bin_attr); + sec->bin_attr.attr.name = sec->raw_name; + sec->bin_attr.attr.mode = 0444; + sec->bin_attr.size = size; + sec->bin_attr.read = vpd_section_read; + sec->bin_attr.private = sec; + + err = sysfs_create_bin_file(vpd_kobj, &sec->bin_attr); + if (err) + goto err_free_raw_name; + + sec->kobj = kobject_create_and_add(name, vpd_kobj); + if (!sec->kobj) { + err = -EINVAL; + goto err_sysfs_remove; + } + + INIT_LIST_HEAD(&sec->attribs); + vpd_section_create_attribs(sec); + + sec->enabled = true; + + return 0; + +err_sysfs_remove: + sysfs_remove_bin_file(vpd_kobj, &sec->bin_attr); +err_free_raw_name: + kfree(sec->raw_name); +err_memunmap: + memunmap(sec->baseaddr); + return err; +} + +static int vpd_section_destroy(struct vpd_section *sec) +{ + if (sec->enabled) { + vpd_section_attrib_destroy(sec); + kobject_put(sec->kobj); + sysfs_remove_bin_file(vpd_kobj, &sec->bin_attr); + kfree(sec->raw_name); + memunmap(sec->baseaddr); + sec->enabled = false; + } + + return 0; +} + +static int vpd_sections_init(phys_addr_t physaddr) +{ + struct vpd_cbmem *temp; + struct vpd_cbmem header; + int ret = 0; + + temp = memremap(physaddr, sizeof(struct vpd_cbmem), MEMREMAP_WB); + if (!temp) + return -ENOMEM; + + memcpy(&header, temp, sizeof(struct vpd_cbmem)); + memunmap(temp); + + if (header.magic != VPD_CBMEM_MAGIC) + return -ENODEV; + + if (header.ro_size) { + ret = vpd_section_init("ro", &ro_vpd, + physaddr + sizeof(struct vpd_cbmem), + header.ro_size); + if (ret) + return ret; + } + + if (header.rw_size) { + ret = vpd_section_init("rw", &rw_vpd, + physaddr + sizeof(struct vpd_cbmem) + + header.ro_size, header.rw_size); + if (ret) { + vpd_section_destroy(&ro_vpd); + return ret; + } + } + + return 0; +} + +static int vpd_probe(struct coreboot_device *dev) +{ + int ret; + + vpd_kobj = kobject_create_and_add("vpd", firmware_kobj); + if (!vpd_kobj) + return -ENOMEM; + + ret = vpd_sections_init(dev->cbmem_ref.cbmem_addr); + if (ret) { + kobject_put(vpd_kobj); + return ret; + } + + return 0; +} + +static void vpd_remove(struct coreboot_device *dev) +{ + vpd_section_destroy(&ro_vpd); + vpd_section_destroy(&rw_vpd); + + kobject_put(vpd_kobj); +} + +static struct coreboot_driver vpd_driver = { + .probe = vpd_probe, + .remove = vpd_remove, + .drv = { + .name = "vpd", + }, + .tag = CB_TAG_VPD, +}; +module_coreboot_driver(vpd_driver); + +MODULE_AUTHOR("Google, Inc."); +MODULE_LICENSE("GPL"); |