/*

   * Copyright (c) 2013 The Chromium OS Authors.

   *

   * SPDX-License-Identifier:	GPL-2.0+

   */
  
  #include <common.h>
  #include <command.h>

  #include <malloc.h>

  #include <tpm.h>

  #include <asm/unaligned.h>
  #include <linux/string.h>

  /* Useful constants */
  enum {
  	DIGEST_LENGTH		= 20,
  	/* max lengths, valid for RSA keys <= 2048 bits */
  	TPM_PUBKEY_MAX_LENGTH	= 288,
  };

  /**
   * Print a byte string in hexdecimal format, 16-bytes per line.
   *
   * @param data		byte string to be printed
   * @param count		number of bytes to be printed
   */
  static void print_byte_string(uint8_t *data, size_t count)
  {
  	int i, print_newline = 0;

  	for (i = 0; i < count; i++) {
  		printf(" %02x", data[i]);
  		print_newline = (i % 16 == 15);
  		if (print_newline)
  			putc('
  ');
  	}
  	/* Avoid duplicated newline at the end */
  	if (!print_newline)
  		putc('
  ');
  }
  
  /**
   * Convert a text string of hexdecimal values into a byte string.

   *

   * @param bytes		text string of hexdecimal values with no space
   *			between them
   * @param data		output buffer for byte string.  The caller has to make
   *			sure it is large enough for storing the output.  If
   *			NULL is passed, a large enough buffer will be allocated,
   *			and the caller must free it.
   * @param count_ptr	output variable for the length of byte string
   * @return pointer to output buffer

   */

  static void *parse_byte_string(char *bytes, uint8_t *data, size_t *count_ptr)
  {
  	char byte[3];
  	size_t count, length;
  	int i;
  
  	length = strlen(bytes);
  	count = length / 2;
  
  	if (!data)
  		data = malloc(count);
  	if (!data)
  		return NULL;
  
  	byte[2] = '\0';
  	for (i = 0; i < length; i += 2) {
  		byte[0] = bytes[i];
  		byte[1] = bytes[i + 1];
  		data[i / 2] = (uint8_t)simple_strtoul(byte, NULL, 16);

  	}

  	if (count_ptr)
  		*count_ptr = count;
  
  	return data;
  }
  
  /**
   * Convert TPM command return code to U-Boot command error codes.
   *
   * @param return_code	TPM command return code
   * @return value of enum command_ret_t
   */
  static int convert_return_code(uint32_t return_code)
  {
  	if (return_code)
  		return CMD_RET_FAILURE;
  	else
  		return CMD_RET_SUCCESS;
  }
  
  /**
   * Return number of values defined by a type string.
   *
   * @param type_str	type string
   * @return number of values of type string
   */
  static int type_string_get_num_values(const char *type_str)
  {
  	return strlen(type_str);
  }
  
  /**
   * Return total size of values defined by a type string.
   *
   * @param type_str	type string
   * @return total size of values of type string, or 0 if type string
   *  contains illegal type character.
   */
  static size_t type_string_get_space_size(const char *type_str)
  {
  	size_t size;
  
  	for (size = 0; *type_str; type_str++) {
  		switch (*type_str) {
  		case 'b':
  			size += 1;
  			break;
  		case 'w':
  			size += 2;
  			break;
  		case 'd':
  			size += 4;
  			break;
  		default:
  			return 0;
  		}

  	}

  
  	return size;

  }

  /**
   * Allocate a buffer large enough to hold values defined by a type
   * string.  The caller has to free the buffer.
   *
   * @param type_str	type string
   * @param count		pointer for storing size of buffer
   * @return pointer to buffer or NULL on error
   */
  static void *type_string_alloc(const char *type_str, uint32_t *count)
  {
  	void *data;
  	size_t size;
  
  	size = type_string_get_space_size(type_str);
  	if (!size)
  		return NULL;
  	data = malloc(size);
  	if (data)
  		*count = size;

  	return data;
  }
  
  /**
   * Pack values defined by a type string into a buffer.  The buffer must have
   * large enough space.
   *
   * @param type_str	type string
   * @param values	text strings of values to be packed
   * @param data		output buffer of values
   * @return 0 on success, non-0 on error
   */
  static int type_string_pack(const char *type_str, char * const values[],
  		uint8_t *data)

  {

  	size_t offset;
  	uint32_t value;
  
  	for (offset = 0; *type_str; type_str++, values++) {
  		value = simple_strtoul(values[0], NULL, 0);
  		switch (*type_str) {
  		case 'b':
  			data[offset] = value;
  			offset += 1;
  			break;
  		case 'w':
  			put_unaligned_be16(value, data + offset);
  			offset += 2;
  			break;
  		case 'd':
  			put_unaligned_be32(value, data + offset);
  			offset += 4;

  			break;

  		default:
  			return -1;

  		}

  	}
  
  	return 0;
  }
  
  /**
   * Read values defined by a type string from a buffer, and write these values
   * to environment variables.
   *
   * @param type_str	type string
   * @param data		input buffer of values
   * @param vars		names of environment variables
   * @return 0 on success, non-0 on error
   */
  static int type_string_write_vars(const char *type_str, uint8_t *data,
  		char * const vars[])
  {
  	size_t offset;
  	uint32_t value;
  
  	for (offset = 0; *type_str; type_str++, vars++) {
  		switch (*type_str) {
  		case 'b':
  			value = data[offset];
  			offset += 1;
  			break;
  		case 'w':
  			value = get_unaligned_be16(data + offset);
  			offset += 2;

  			break;

  		case 'd':
  			value = get_unaligned_be32(data + offset);
  			offset += 4;
  			break;
  		default:
  			return -1;

  		}

  		if (setenv_ulong(*vars, value))
  			return -1;

  	}

  
  	return 0;

  }

  static int do_tpm_startup(cmd_tbl_t *cmdtp, int flag,
  		int argc, char * const argv[])
  {
  	enum tpm_startup_type mode;

  	if (argc != 2)
  		return CMD_RET_USAGE;
  	if (!strcasecmp("TPM_ST_CLEAR", argv[1])) {
  		mode = TPM_ST_CLEAR;
  	} else if (!strcasecmp("TPM_ST_STATE", argv[1])) {
  		mode = TPM_ST_STATE;
  	} else if (!strcasecmp("TPM_ST_DEACTIVATED", argv[1])) {
  		mode = TPM_ST_DEACTIVATED;
  	} else {
  		printf("Couldn't recognize mode string: %s
  ", argv[1]);
  		return CMD_RET_FAILURE;
  	}
  
  	return convert_return_code(tpm_startup(mode));
  }
  
  static int do_tpm_nv_define_space(cmd_tbl_t *cmdtp, int flag,
  		int argc, char * const argv[])
  {
  	uint32_t index, perm, size;
  
  	if (argc != 4)
  		return CMD_RET_USAGE;
  	index = simple_strtoul(argv[1], NULL, 0);
  	perm = simple_strtoul(argv[2], NULL, 0);
  	size = simple_strtoul(argv[3], NULL, 0);
  
  	return convert_return_code(tpm_nv_define_space(index, perm, size));
  }

  static int do_tpm_nv_read_value(cmd_tbl_t *cmdtp, int flag,
  		int argc, char * const argv[])

  {

  	uint32_t index, count, rc;
  	void *data;

  	if (argc != 4)
  		return CMD_RET_USAGE;
  	index = simple_strtoul(argv[1], NULL, 0);
  	data = (void *)simple_strtoul(argv[2], NULL, 0);
  	count = simple_strtoul(argv[3], NULL, 0);
  
  	rc = tpm_nv_read_value(index, data, count);
  	if (!rc) {
  		puts("area content:
  ");
  		print_byte_string(data, count);

  	}

  	return convert_return_code(rc);
  }
  
  static int do_tpm_nv_write_value(cmd_tbl_t *cmdtp, int flag,
  		int argc, char * const argv[])
  {
  	uint32_t index, rc;
  	size_t count;
  	void *data;
  
  	if (argc != 3)
  		return CMD_RET_USAGE;
  	index = simple_strtoul(argv[1], NULL, 0);
  	data = parse_byte_string(argv[2], NULL, &count);
  	if (!data) {
  		printf("Couldn't parse byte string %s
  ", argv[2]);
  		return CMD_RET_FAILURE;

  	}

  	rc = tpm_nv_write_value(index, data, count);
  	free(data);
  
  	return convert_return_code(rc);
  }
  
  static int do_tpm_extend(cmd_tbl_t *cmdtp, int flag,
  		int argc, char * const argv[])
  {
  	uint32_t index, rc;
  	uint8_t in_digest[20], out_digest[20];
  
  	if (argc != 3)
  		return CMD_RET_USAGE;
  	index = simple_strtoul(argv[1], NULL, 0);
  	if (!parse_byte_string(argv[2], in_digest, NULL)) {
  		printf("Couldn't parse byte string %s
  ", argv[2]);
  		return CMD_RET_FAILURE;

  	}

  	rc = tpm_extend(index, in_digest, out_digest);
  	if (!rc) {
  		puts("PCR value after execution of the command:
  ");
  		print_byte_string(out_digest, sizeof(out_digest));

  	}

  	return convert_return_code(rc);
  }
  
  static int do_tpm_pcr_read(cmd_tbl_t *cmdtp, int flag,
  		int argc, char * const argv[])
  {
  	uint32_t index, count, rc;
  	void *data;
  
  	if (argc != 4)
  		return CMD_RET_USAGE;
  	index = simple_strtoul(argv[1], NULL, 0);
  	data = (void *)simple_strtoul(argv[2], NULL, 0);
  	count = simple_strtoul(argv[3], NULL, 0);

  	rc = tpm_pcr_read(index, data, count);
  	if (!rc) {
  		puts("Named PCR content:
  ");
  		print_byte_string(data, count);

  	}

  	return convert_return_code(rc);

  }

  static int do_tpm_tsc_physical_presence(cmd_tbl_t *cmdtp, int flag,
  		int argc, char * const argv[])
  {
  	uint16_t presence;
  
  	if (argc != 2)
  		return CMD_RET_USAGE;
  	presence = (uint16_t)simple_strtoul(argv[1], NULL, 0);

  	return convert_return_code(tpm_tsc_physical_presence(presence));
  }
  
  static int do_tpm_read_pubek(cmd_tbl_t *cmdtp, int flag,
  		int argc, char * const argv[])

  {

  	uint32_t count, rc;
  	void *data;
  
  	if (argc != 3)
  		return CMD_RET_USAGE;
  	data = (void *)simple_strtoul(argv[1], NULL, 0);
  	count = simple_strtoul(argv[2], NULL, 0);
  
  	rc = tpm_read_pubek(data, count);
  	if (!rc) {
  		puts("pubek value:
  ");
  		print_byte_string(data, count);
  	}
  
  	return convert_return_code(rc);

  }

  static int do_tpm_physical_set_deactivated(cmd_tbl_t *cmdtp, int flag,
  		int argc, char * const argv[])
  {
  	uint8_t state;
  
  	if (argc != 2)
  		return CMD_RET_USAGE;
  	state = (uint8_t)simple_strtoul(argv[1], NULL, 0);

  	return convert_return_code(tpm_physical_set_deactivated(state));
  }
  
  static int do_tpm_get_capability(cmd_tbl_t *cmdtp, int flag,
  		int argc, char * const argv[])
  {
  	uint32_t cap_area, sub_cap, rc;
  	void *cap;
  	size_t count;
  
  	if (argc != 5)
  		return CMD_RET_USAGE;
  	cap_area = simple_strtoul(argv[1], NULL, 0);
  	sub_cap = simple_strtoul(argv[2], NULL, 0);
  	cap = (void *)simple_strtoul(argv[3], NULL, 0);
  	count = simple_strtoul(argv[4], NULL, 0);
  
  	rc = tpm_get_capability(cap_area, sub_cap, cap, count);
  	if (!rc) {
  		puts("capability information:
  ");
  		print_byte_string(cap, count);
  	}
  
  	return convert_return_code(rc);
  }

  #define TPM_COMMAND_NO_ARG(cmd)				\
  static int do_##cmd(cmd_tbl_t *cmdtp, int flag,		\
  		int argc, char * const argv[])		\
  {							\
  	if (argc != 1)					\
  		return CMD_RET_USAGE;			\
  	return convert_return_code(cmd());		\
  }
  
  TPM_COMMAND_NO_ARG(tpm_init)
  TPM_COMMAND_NO_ARG(tpm_self_test_full)
  TPM_COMMAND_NO_ARG(tpm_continue_self_test)
  TPM_COMMAND_NO_ARG(tpm_force_clear)
  TPM_COMMAND_NO_ARG(tpm_physical_enable)
  TPM_COMMAND_NO_ARG(tpm_physical_disable)
  
  static int do_tpm_raw_transfer(cmd_tbl_t *cmdtp, int flag,
  		int argc, char * const argv[])
  {
  	void *command;
  	uint8_t response[1024];
  	size_t count, response_length = sizeof(response);
  	uint32_t rc;
  
  	command = parse_byte_string(argv[1], NULL, &count);
  	if (!command) {
  		printf("Couldn't parse byte string %s
  ", argv[1]);
  		return CMD_RET_FAILURE;
  	}
  
  	rc = tis_sendrecv(command, count, response, &response_length);
  	free(command);
  	if (!rc) {
  		puts("tpm response:
  ");
  		print_byte_string(response, response_length);
  	}
  
  	return convert_return_code(rc);
  }
  
  static int do_tpm_nv_define(cmd_tbl_t *cmdtp, int flag,
  		int argc, char * const argv[])
  {
  	uint32_t index, perm, size;
  
  	if (argc != 4)
  		return CMD_RET_USAGE;
  	size = type_string_get_space_size(argv[1]);
  	if (!size) {
  		printf("Couldn't parse arguments
  ");
  		return CMD_RET_USAGE;
  	}
  	index = simple_strtoul(argv[2], NULL, 0);
  	perm = simple_strtoul(argv[3], NULL, 0);
  
  	return convert_return_code(tpm_nv_define_space(index, perm, size));
  }
  
  static int do_tpm_nv_read(cmd_tbl_t *cmdtp, int flag,
  		int argc, char * const argv[])

  {

  	uint32_t index, count, err;
  	void *data;

  	if (argc < 3)
  		return CMD_RET_USAGE;
  	if (argc != 3 + type_string_get_num_values(argv[1]))
  		return CMD_RET_USAGE;
  	index = simple_strtoul(argv[2], NULL, 0);
  	data = type_string_alloc(argv[1], &count);
  	if (!data) {
  		printf("Couldn't parse arguments
  ");
  		return CMD_RET_USAGE;

  	}

  	err = tpm_nv_read_value(index, data, count);
  	if (!err) {
  		if (type_string_write_vars(argv[1], data, argv + 3)) {
  			printf("Couldn't write to variables
  ");
  			err = ~0;
  		}

  	}

  	free(data);
  
  	return convert_return_code(err);
  }
  
  static int do_tpm_nv_write(cmd_tbl_t *cmdtp, int flag,
  		int argc, char * const argv[])
  {
  	uint32_t index, count, err;
  	void *data;
  
  	if (argc < 3)
  		return CMD_RET_USAGE;
  	if (argc != 3 + type_string_get_num_values(argv[1]))
  		return CMD_RET_USAGE;
  	index = simple_strtoul(argv[2], NULL, 0);
  	data = type_string_alloc(argv[1], &count);
  	if (!data) {
  		printf("Couldn't parse arguments
  ");
  		return CMD_RET_USAGE;
  	}
  	if (type_string_pack(argv[1], argv + 3, data)) {
  		printf("Couldn't parse arguments
  ");
  		free(data);
  		return CMD_RET_USAGE;
  	}
  
  	err = tpm_nv_write_value(index, data, count);
  	free(data);
  
  	return convert_return_code(err);
  }

  #ifdef CONFIG_TPM_AUTH_SESSIONS
  
  static int do_tpm_oiap(cmd_tbl_t *cmdtp, int flag,
  		int argc, char * const argv[])
  {
  	uint32_t auth_handle, err;
  
  	err = tpm_oiap(&auth_handle);
  
  	return convert_return_code(err);
  }
  
  static int do_tpm_load_key2_oiap(cmd_tbl_t *cmdtp, int flag,
  		int argc, char * const argv[])
  {
  	uint32_t parent_handle, key_len, key_handle, err;
  	uint8_t usage_auth[DIGEST_LENGTH];
  	void *key;
  
  	if (argc < 5)
  		return CMD_RET_USAGE;
  
  	parent_handle = simple_strtoul(argv[1], NULL, 0);
  	key = (void *)simple_strtoul(argv[2], NULL, 0);
  	key_len = simple_strtoul(argv[3], NULL, 0);
  	if (strlen(argv[4]) != 2 * DIGEST_LENGTH)
  		return CMD_RET_FAILURE;
  	parse_byte_string(argv[4], usage_auth, NULL);
  
  	err = tpm_load_key2_oiap(parent_handle, key, key_len, usage_auth,
  			&key_handle);
  	if (!err)
  		printf("Key handle is 0x%x
  ", key_handle);
  
  	return convert_return_code(err);
  }
  
  static int do_tpm_get_pub_key_oiap(cmd_tbl_t *cmdtp, int flag,
  		int argc, char * const argv[])
  {
  	uint32_t key_handle, err;
  	uint8_t usage_auth[DIGEST_LENGTH];
  	uint8_t pub_key_buffer[TPM_PUBKEY_MAX_LENGTH];
  	size_t pub_key_len = sizeof(pub_key_buffer);
  
  	if (argc < 3)
  		return CMD_RET_USAGE;
  
  	key_handle = simple_strtoul(argv[1], NULL, 0);
  	if (strlen(argv[2]) != 2 * DIGEST_LENGTH)
  		return CMD_RET_FAILURE;
  	parse_byte_string(argv[2], usage_auth, NULL);
  
  	err = tpm_get_pub_key_oiap(key_handle, usage_auth,
  			pub_key_buffer, &pub_key_len);
  	if (!err) {
  		printf("dump of received pub key structure:
  ");
  		print_byte_string(pub_key_buffer, pub_key_len);
  	}
  	return convert_return_code(err);
  }
  
  TPM_COMMAND_NO_ARG(tpm_end_oiap)
  
  #endif /* CONFIG_TPM_AUTH_SESSIONS */

  #define MAKE_TPM_CMD_ENTRY(cmd) \
  	U_BOOT_CMD_MKENT(cmd, 0, 1, do_tpm_ ## cmd, "", "")
  
  static cmd_tbl_t tpm_commands[] = {
  	U_BOOT_CMD_MKENT(init, 0, 1,
  			do_tpm_init, "", ""),
  	U_BOOT_CMD_MKENT(startup, 0, 1,
  			do_tpm_startup, "", ""),
  	U_BOOT_CMD_MKENT(self_test_full, 0, 1,
  			do_tpm_self_test_full, "", ""),
  	U_BOOT_CMD_MKENT(continue_self_test, 0, 1,
  			do_tpm_continue_self_test, "", ""),
  	U_BOOT_CMD_MKENT(force_clear, 0, 1,
  			do_tpm_force_clear, "", ""),
  	U_BOOT_CMD_MKENT(physical_enable, 0, 1,
  			do_tpm_physical_enable, "", ""),
  	U_BOOT_CMD_MKENT(physical_disable, 0, 1,
  			do_tpm_physical_disable, "", ""),
  	U_BOOT_CMD_MKENT(nv_define_space, 0, 1,
  			do_tpm_nv_define_space, "", ""),
  	U_BOOT_CMD_MKENT(nv_read_value, 0, 1,
  			do_tpm_nv_read_value, "", ""),
  	U_BOOT_CMD_MKENT(nv_write_value, 0, 1,
  			do_tpm_nv_write_value, "", ""),
  	U_BOOT_CMD_MKENT(extend, 0, 1,
  			do_tpm_extend, "", ""),
  	U_BOOT_CMD_MKENT(pcr_read, 0, 1,
  			do_tpm_pcr_read, "", ""),
  	U_BOOT_CMD_MKENT(tsc_physical_presence, 0, 1,
  			do_tpm_tsc_physical_presence, "", ""),
  	U_BOOT_CMD_MKENT(read_pubek, 0, 1,
  			do_tpm_read_pubek, "", ""),
  	U_BOOT_CMD_MKENT(physical_set_deactivated, 0, 1,
  			do_tpm_physical_set_deactivated, "", ""),
  	U_BOOT_CMD_MKENT(get_capability, 0, 1,
  			do_tpm_get_capability, "", ""),
  	U_BOOT_CMD_MKENT(raw_transfer, 0, 1,
  			do_tpm_raw_transfer, "", ""),
  	U_BOOT_CMD_MKENT(nv_define, 0, 1,
  			do_tpm_nv_define, "", ""),
  	U_BOOT_CMD_MKENT(nv_read, 0, 1,
  			do_tpm_nv_read, "", ""),
  	U_BOOT_CMD_MKENT(nv_write, 0, 1,
  			do_tpm_nv_write, "", ""),

  #ifdef CONFIG_TPM_AUTH_SESSIONS
  	U_BOOT_CMD_MKENT(oiap, 0, 1,
  			 do_tpm_oiap, "", ""),
  	U_BOOT_CMD_MKENT(end_oiap, 0, 1,
  			 do_tpm_end_oiap, "", ""),
  	U_BOOT_CMD_MKENT(load_key2_oiap, 0, 1,
  			 do_tpm_load_key2_oiap, "", ""),
  	U_BOOT_CMD_MKENT(get_pub_key_oiap, 0, 1,
  			 do_tpm_get_pub_key_oiap, "", ""),
  #endif /* CONFIG_TPM_AUTH_SESSIONS */

  };
  
  static int do_tpm(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
  {
  	cmd_tbl_t *tpm_cmd;
  
  	if (argc < 2)
  		return CMD_RET_USAGE;
  	tpm_cmd = find_cmd_tbl(argv[1], tpm_commands, ARRAY_SIZE(tpm_commands));
  	if (!tpm_cmd)
  		return CMD_RET_USAGE;

  	return tpm_cmd->cmd(cmdtp, flag, argc - 1, argv + 1);

  }

  U_BOOT_CMD(tpm, CONFIG_SYS_MAXARGS, 1, do_tpm,
  "Issue a TPM command",
  "cmd args...
  "
  "    - Issue TPM command <cmd> with arguments <args...>.
  "
  "Admin Startup and State Commands:
  "
  "  init
  "
  "    - Put TPM into a state where it waits for 'startup' command.
  "
  "  startup mode
  "
  "    - Issue TPM_Starup command.  <mode> is one of TPM_ST_CLEAR,
  "
  "      TPM_ST_STATE, and TPM_ST_DEACTIVATED.
  "
  "Admin Testing Commands:
  "
  "  self_test_full
  "
  "    - Test all of the TPM capabilities.
  "
  "  continue_self_test
  "
  "    - Inform TPM that it should complete the self-test.
  "
  "Admin Opt-in Commands:
  "
  "  physical_enable
  "
  "    - Set the PERMANENT disable flag to FALSE using physical presence as
  "
  "      authorization.
  "
  "  physical_disable
  "
  "    - Set the PERMANENT disable flag to TRUE using physical presence as
  "
  "      authorization.
  "
  "  physical_set_deactivated 0|1
  "
  "    - Set deactivated flag.
  "
  "Admin Ownership Commands:
  "
  "  force_clear
  "
  "    - Issue TPM_ForceClear command.
  "
  "  tsc_physical_presence flags
  "
  "    - Set TPM device's Physical Presence flags to <flags>.
  "
  "The Capability Commands:
  "
  "  get_capability cap_area sub_cap addr count
  "
  "    - Read <count> bytes of TPM capability indexed by <cap_area> and
  "
  "      <sub_cap> to memory address <addr>.
  "

  #ifdef CONFIG_TPM_AUTH_SESSIONS
  "Storage functions
  "
  "  loadkey2_oiap parent_handle key_addr key_len usage_auth
  "
  "    - loads a key data from memory address <key_addr>, <key_len> bytes
  "
  "      into TPM using the parent key <parent_handle> with authorization
  "
  "      <usage_auth> (20 bytes hex string).
  "
  "  get_pub_key_oiap key_handle usage_auth
  "
  "    - get the public key portion of a loaded key <key_handle> using
  "
  "      authorization <usage auth> (20 bytes hex string)
  "
  #endif /* CONFIG_TPM_AUTH_SESSIONS */

  "Endorsement Key Handling Commands:
  "
  "  read_pubek addr count
  "
  "    - Read <count> bytes of the public endorsement key to memory
  "
  "      address <addr>
  "
  "Integrity Collection and Reporting Commands:
  "
  "  extend index digest_hex_string
  "
  "    - Add a new measurement to a PCR.  Update PCR <index> with the 20-bytes
  "
  "      <digest_hex_string>
  "
  "  pcr_read index addr count
  "
  "    - Read <count> bytes from PCR <index> to memory address <addr>.
  "

  #ifdef CONFIG_TPM_AUTH_SESSIONS
  "Authorization Sessions
  "
  "  oiap
  "
  "    - setup an OIAP session
  "
  "  end_oiap
  "
  "    - terminates an active OIAP session
  "
  #endif /* CONFIG_TPM_AUTH_SESSIONS */

  "Non-volatile Storage Commands:
  "
  "  nv_define_space index permission size
  "
  "    - Establish a space at index <index> with <permission> of <size> bytes.
  "
  "  nv_read_value index addr count
  "
  "    - Read <count> bytes from space <index> to memory address <addr>.
  "
  "  nv_write_value index addr count
  "
  "    - Write <count> bytes from memory address <addr> to space <index>.
  "
  "Miscellaneous helper functions:
  "
  "  raw_transfer byte_string
  "
  "    - Send a byte string <byte_string> to TPM and print the response.
  "
  " Non-volatile storage helper functions:
  "
  "    These helper functions treat a non-volatile space as a non-padded
  "
  "    sequence of integer values.  These integer values are defined by a type
  "
  "    string, which is a text string of 'bwd' characters: 'b' means a 8-bit
  "
  "    value, 'w' 16-bit value, 'd' 32-bit value.  All helper functions take
  "
  "    a type string as their first argument.
  "
  "  nv_define type_string index perm
  "
  "    - Define a space <index> with permission <perm>.
  "
  "  nv_read types_string index vars...
  "
  "    - Read from space <index> to environment variables <vars...>.
  "
  "  nv_write types_string index values...
  "
  "    - Write to space <index> from values <values...>.
  "

  );