/*
* vpd.c
*
* Driver for exporting VPD content to sysfs.
*
* Copyright 2017 Google Inc.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License v2.0 as published by
* the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*/
#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[0];
};
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, s32 key_len,
const u8 *value, s32 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);
info->key = kzalloc(key_len + 1, GFP_KERNEL);
if (!info->key)
return -ENOMEM;
memcpy(info->key, key, key_len);
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);
list_add_tail(&info->list, &sec->attribs);
ret = sysfs_create_bin_file(sec->kobj, &info->bin_attr);
if (ret) {
kfree(info->key);
return ret;
}
return 0;
}
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) {
kfree(info->key);
sysfs_remove_bin_file(sec->kobj, &info->bin_attr);
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 ret;
int raw_len;
sec->baseaddr = memremap(physaddr, size, MEMREMAP_WB);
if (!sec->baseaddr)
return -ENOMEM;
sec->name = name;
/* We want to export the raw partion with name ${name}_raw */
raw_len = strlen(name) + 5;
sec->raw_name = kzalloc(raw_len, GFP_KERNEL);
strncpy(sec->raw_name, name, raw_len);
strncat(sec->raw_name, "_raw", raw_len);
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;
ret = sysfs_create_bin_file(vpd_kobj, &sec->bin_attr);
if (ret)
goto free_sec;
sec->kobj = kobject_create_and_add(name, vpd_kobj);
if (!sec->kobj) {
ret = -EINVAL;
goto sysfs_remove;
}
INIT_LIST_HEAD(&sec->attribs);
vpd_section_create_attribs(sec);
sec->enabled = true;
return 0;
sysfs_remove:
sysfs_remove_bin_file(vpd_kobj, &sec->bin_attr);
free_sec:
kfree(sec->raw_name);
iounmap(sec->baseaddr);
return ret;
}
static int vpd_section_destroy(struct vpd_section *sec)
{
if (sec->enabled) {
vpd_section_attrib_destroy(sec);
kobject_del(sec->kobj);
sysfs_remove_bin_file(vpd_kobj, &sec->bin_attr);
kfree(sec->raw_name);
iounmap(sec->baseaddr);
}
return 0;
}
static int vpd_sections_init(phys_addr_t physaddr)
{
struct vpd_cbmem __iomem *temp;
struct vpd_cbmem header;
int ret = 0;
temp = memremap(physaddr, sizeof(struct vpd_cbmem), MEMREMAP_WB);
if (!temp)
return -ENOMEM;
memcpy_fromio(&header, temp, sizeof(struct vpd_cbmem));
iounmap(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)
return ret;
}
return 0;
}
static int vpd_probe(struct platform_device *pdev)
{
int ret;
struct lb_cbmem_ref entry;
ret = coreboot_table_find(CB_TAG_VPD, &entry, sizeof(entry));
if (ret)
return ret;
return vpd_sections_init(entry.cbmem_addr);
}
static struct platform_driver vpd_driver = {
.probe = vpd_probe,
.driver = {
.name = "vpd",
},
};
static int __init vpd_platform_init(void)
{
struct platform_device *pdev;
pdev = platform_device_register_simple("vpd", -1, NULL, 0);
if (!pdev)
return -ENODEV;
vpd_kobj = kobject_create_and_add("vpd", firmware_kobj);
if (!vpd_kobj)
return -ENOMEM;
memset(&ro_vpd, 0, sizeof(ro_vpd));
memset(&rw_vpd, 0, sizeof(rw_vpd));
platform_driver_register(&vpd_driver);
return 0;
}
static void __exit vpd_platform_exit(void)
{
vpd_section_destroy(&ro_vpd);
vpd_section_destroy(&rw_vpd);
kobject_del(vpd_kobj);
}
module_init(vpd_platform_init);
module_exit(vpd_platform_exit);
MODULE_AUTHOR("Google, Inc.");
MODULE_LICENSE("GPL");
