text: /* Copyright (c) 2012-2014, The Linux Foundation. All rights reserved.
   *
   * This program is free software; you can redistribute it and/or modify
   * it under the terms of the GNU General Public License version 2 and
   * only version 2 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.
   */
  
  #ifndef _QMI_ENCDEC_H_
  #define _QMI_ENCDEC_H_
  
  #include <linux/types.h>
  #include <linux/errno.h>
  #include <linux/mm.h>
  #include <linux/list.h>
  #include <linux/socket.h>
  #include <linux/gfp.h>
  
  #define QMI_REQUEST_CONTROL_FLAG 0x00
  #define QMI_RESPONSE_CONTROL_FLAG 0x02
  #define QMI_INDICATION_CONTROL_FLAG 0x04
  #define QMI_HEADER_SIZE 7
  
  /**
   * elem_type - Enum to identify the data type of elements in a data
   *             structure.
   */
  enum elem_type {
  	QMI_OPT_FLAG = 1,
  	QMI_DATA_LEN,
  	QMI_UNSIGNED_1_BYTE,
  	QMI_UNSIGNED_2_BYTE,
  	QMI_UNSIGNED_4_BYTE,
  	QMI_UNSIGNED_8_BYTE,
  	QMI_SIGNED_2_BYTE_ENUM,
  	QMI_SIGNED_4_BYTE_ENUM,
  	QMI_STRUCT,
  	QMI_STRING,
  	QMI_EOTI,
  };
  
  /**
   * array_type - Enum to identify if an element in a data structure is
   *              an array. If so, then is it a static length array or a
   *              variable length array.
   */
  enum array_type {
  	NO_ARRAY = 0,
  	STATIC_ARRAY = 1,
  	VAR_LEN_ARRAY = 2,
  };
  
  /**
   * elem_info - Data structure to specify information about an element
   *               in a data structure. An array of this data structure
   *               can be used to specify info about a complex data
   *               structure to be encoded/decoded.
   *
   * @data_type: Data type of this element.
   * @elem_len: Array length of this element, if an array.
   * @elem_size: Size of a single instance of this data type.
   * @is_array: Array type of this element.
   * @tlv_type: QMI message specific type to identify which element
   *            is present in an incoming message.
   * @offset: To identify the address of the first instance of this
   *          element in the data structure.
   * @ei_array: Array to provide information about the nested structure
   *            within a data structure to be encoded/decoded.
   */
  struct elem_info {
  	enum elem_type data_type;
  	uint32_t elem_len;
  	uint32_t elem_size;
  	enum array_type is_array;
  	uint8_t tlv_type;
  	uint32_t offset;
  	struct elem_info *ei_array;
  };
  
  /**
   * @msg_desc - Describe about the main/outer structure to be
   *		  encoded/decoded.
   *
   * @max_msg_len: Maximum possible length of the QMI message.
   * @ei_array: Array to provide information about a data structure.
   */
  struct msg_desc {
  	uint16_t msg_id;
  	int max_msg_len;
  	struct elem_info *ei_array;
  };
  
  struct qmi_header {
  	unsigned char cntl_flag;
  	uint16_t txn_id;
  	uint16_t msg_id;
  	uint16_t msg_len;
  } __attribute__((__packed__));
  
  static inline void encode_qmi_header(unsigned char *buf,
  			unsigned char cntl_flag, uint16_t txn_id,
  			uint16_t msg_id, uint16_t msg_len)
  {
  	struct qmi_header *hdr = (struct qmi_header *)buf;
  
  	hdr->cntl_flag = cntl_flag;
  	hdr->txn_id = txn_id;
  	hdr->msg_id = msg_id;
  	hdr->msg_len = msg_len;
  }
  
  static inline void decode_qmi_header(unsigned char *buf,
  			unsigned char *cntl_flag, uint16_t *txn_id,
  			uint16_t *msg_id, uint16_t *msg_len)
  {
  	struct qmi_header *hdr = (struct qmi_header *)buf;
  
  	*cntl_flag = hdr->cntl_flag;
  	*txn_id = hdr->txn_id;
  	*msg_id = hdr->msg_id;
  	*msg_len = hdr->msg_len;
  }
  
  #ifdef CONFIG_QMI_ENCDEC
  /**
   * qmi_kernel_encode() - Encode to QMI message wire format
   * @desc: Pointer to structure descriptor.
   * @out_buf: Buffer to hold the encoded QMI message.
   * @out_buf_len: Length of the out buffer.
   * @in_c_struct: C Structure to be encoded.
   *
   * @return: size of encoded message on success, < 0 on error.
   */
  int qmi_kernel_encode(struct msg_desc *desc,
  		      void *out_buf, uint32_t out_buf_len,
  		      void *in_c_struct);
  
  /**
   * qmi_kernel_decode() - Decode to C Structure format
   * @desc: Pointer to structure descriptor.
   * @out_c_struct: Buffer to hold the decoded C structure.
   * @in_buf: Buffer containg the QMI message to be decoded.
   * @in_buf_len: Length of the incoming QMI message.
   *
   * @return: 0 on success, < 0 on error.
   */
  int qmi_kernel_decode(struct msg_desc *desc, void *out_c_struct,
  		      void *in_buf, uint32_t in_buf_len);
  
  /**
   * qmi_verify_max_msg_len() - Verify the maximum length of a QMI message
   * @desc: Pointer to structure descriptor.
   *
   * @return: true if the maximum message length embedded in structure
   *          descriptor matches the calculated value, else false.
   */
  bool qmi_verify_max_msg_len(struct msg_desc *desc);
  
  #else
  static inline int qmi_kernel_encode(struct msg_desc *desc,
  				    void *out_buf, uint32_t out_buf_len,
  				    void *in_c_struct)
  {
  	return -EOPNOTSUPP;
  }
  
  static inline int qmi_kernel_decode(struct msg_desc *desc,
  				    void *out_c_struct,
  				    void *in_buf, uint32_t in_buf_len)
  {
  	return -EOPNOTSUPP;
  }
  
  static inline bool qmi_verify_max_msg_len(struct msg_desc *desc)
  {
  	return false;
  }
  #endif
  
  #endif
  