drivers/firmware/google/vpd.c - linux - Git at Google

 /*
  * 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);
 	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 __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));
 	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 int vpd_remove(struct coreboot_device *dev)
 {
 	vpd_section_destroy(&ro_vpd);
 	vpd_section_destroy(&rw_vpd);

 	kobject_put(vpd_kobj);

 	return 0;
 }

 static struct coreboot_driver vpd_driver = {
 	.probe = vpd_probe,
 	.remove = vpd_remove,
 	.drv = {
 		.name = "vpd",
 	},
 	.tag = CB_TAG_VPD,
 };

 static int __init coreboot_vpd_init(void)
 {
 	return coreboot_driver_register(&vpd_driver);
 }

 static void __exit coreboot_vpd_exit(void)
 {
 	coreboot_driver_unregister(&vpd_driver);
 }

 module_init(coreboot_vpd_init);
 module_exit(coreboot_vpd_exit);

 MODULE_AUTHOR("Google, Inc.");
 MODULE_LICENSE("GPL");
	/*
	* 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);
	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 __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));
	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 int vpd_remove(struct coreboot_device *dev)
	{
	vpd_section_destroy(&ro_vpd);
	vpd_section_destroy(&rw_vpd);

	kobject_put(vpd_kobj);

	return 0;
	}

	static struct coreboot_driver vpd_driver = {
	.probe = vpd_probe,
	.remove = vpd_remove,
	.drv = {
	.name = "vpd",
	},
	.tag = CB_TAG_VPD,
	};

	static int __init coreboot_vpd_init(void)
	{
	return coreboot_driver_register(&vpd_driver);
	}

	static void __exit coreboot_vpd_exit(void)
	{
	coreboot_driver_unregister(&vpd_driver);
	}

	module_init(coreboot_vpd_init);
	module_exit(coreboot_vpd_exit);

	MODULE_AUTHOR("Google, Inc.");
	MODULE_LICENSE("GPL");