--- /dev/null
+/*
+ * 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");
projects / karo-tx-linux.git / commitdiff