lib: qmi: Introduce QMI Encode/Decode library
Introduce Encode/Decode Library to perform QMI message marshaling.
The QMI Encode/Decode Library encodes the kernel C data structures into
QMI wire format and decodes the messages in QMI wire format into kernel
C structures.
Change-Id: Ib443e697dafedeac8a790de9a3a8ed4a8444082f
Signed-off-by: Karthikeyan Ramasubramanian <kramasub@codeaurora.org>
diff --git a/include/linux/qmi_encdec.h b/include/linux/qmi_encdec.h
new file mode 100644
index 0000000..4c5f6d3
--- /dev/null
+++ b/include/linux/qmi_encdec.h
@@ -0,0 +1,169 @@
+/* Copyright (c) 2012, 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_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);
+
+#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;
+}
+#endif
+
+#endif