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authorBjorn Andersson <bjorn.andersson@linaro.org>2017-12-05 09:43:06 -0800
committerAndy Gross <andy.gross@linaro.org>2017-12-20 15:38:34 -0600
commit9b8a11e82615274d4133aab3cf5aa1c59191f0a2 (patch)
tree46d63ee16127074c9e2bdf30f4cac6544afdd60f /drivers/soc
parent29ff62f7db108854cd98f5cdc92d15ccb37e81d1 (diff)
soc: qcom: Introduce QMI encoder/decoder
Add the helper library for encoding and decoding QMI encoded messages. The implementation is taken from lib/qmi_encdec.c of the Qualcomm kernel (msm-3.18). Modifications has been made to the public API, source buffers has been made const and the debug-logging part was omitted, for now. Acked-by: Chris Lew <clew@codeaurora.org> Tested-by: Chris Lew <clew@codeaurora.org> Tested-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org> Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org> Signed-off-by: Andy Gross <andy.gross@linaro.org>
Diffstat (limited to 'drivers/soc')
-rw-r--r--drivers/soc/qcom/Kconfig9
-rw-r--r--drivers/soc/qcom/Makefile2
-rw-r--r--drivers/soc/qcom/qmi_encdec.c816
3 files changed, 827 insertions, 0 deletions
diff --git a/drivers/soc/qcom/Kconfig b/drivers/soc/qcom/Kconfig
index 40c711583f0d..e050eb83341d 100644
--- a/drivers/soc/qcom/Kconfig
+++ b/drivers/soc/qcom/Kconfig
@@ -35,6 +35,15 @@ config QCOM_PM
modes. It interface with various system drivers to put the cores in
low power modes.
+config QCOM_QMI_HELPERS
+ tristate
+ depends on ARCH_QCOM
+ help
+ Helper library for handling QMI encoded messages. QMI encoded
+ messages are used in communication between the majority of QRTR
+ clients and this helpers provide the common functionality needed for
+ doing this from a kernel driver.
+
config QCOM_RMTFS_MEM
tristate "Qualcomm Remote Filesystem memory driver"
depends on ARCH_QCOM
diff --git a/drivers/soc/qcom/Makefile b/drivers/soc/qcom/Makefile
index 40c56f67e94a..37f85b45d0a1 100644
--- a/drivers/soc/qcom/Makefile
+++ b/drivers/soc/qcom/Makefile
@@ -3,6 +3,8 @@ obj-$(CONFIG_QCOM_GLINK_SSR) += glink_ssr.o
obj-$(CONFIG_QCOM_GSBI) += qcom_gsbi.o
obj-$(CONFIG_QCOM_MDT_LOADER) += mdt_loader.o
obj-$(CONFIG_QCOM_PM) += spm.o
+obj-$(CONFIG_QCOM_QMI_HELPERS) += qmi_helpers.o
+qmi_helpers-y += qmi_encdec.o
obj-$(CONFIG_QCOM_RMTFS_MEM) += rmtfs_mem.o
obj-$(CONFIG_QCOM_SMD_RPM) += smd-rpm.o
obj-$(CONFIG_QCOM_SMEM) += smem.o
diff --git a/drivers/soc/qcom/qmi_encdec.c b/drivers/soc/qcom/qmi_encdec.c
new file mode 100644
index 000000000000..3aaab71d1b2c
--- /dev/null
+++ b/drivers/soc/qcom/qmi_encdec.c
@@ -0,0 +1,816 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2012-2015, The Linux Foundation. All rights reserved.
+ * Copyright (C) 2017 Linaro Ltd.
+ */
+#include <linux/slab.h>
+#include <linux/uaccess.h>
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/string.h>
+#include <linux/soc/qcom/qmi.h>
+
+#define QMI_ENCDEC_ENCODE_TLV(type, length, p_dst) do { \
+ *p_dst++ = type; \
+ *p_dst++ = ((u8)((length) & 0xFF)); \
+ *p_dst++ = ((u8)(((length) >> 8) & 0xFF)); \
+} while (0)
+
+#define QMI_ENCDEC_DECODE_TLV(p_type, p_length, p_src) do { \
+ *p_type = (u8)*p_src++; \
+ *p_length = (u8)*p_src++; \
+ *p_length |= ((u8)*p_src) << 8; \
+} while (0)
+
+#define QMI_ENCDEC_ENCODE_N_BYTES(p_dst, p_src, size) \
+do { \
+ memcpy(p_dst, p_src, size); \
+ p_dst = (u8 *)p_dst + size; \
+ p_src = (u8 *)p_src + size; \
+} while (0)
+
+#define QMI_ENCDEC_DECODE_N_BYTES(p_dst, p_src, size) \
+do { \
+ memcpy(p_dst, p_src, size); \
+ p_dst = (u8 *)p_dst + size; \
+ p_src = (u8 *)p_src + size; \
+} while (0)
+
+#define UPDATE_ENCODE_VARIABLES(temp_si, buf_dst, \
+ encoded_bytes, tlv_len, encode_tlv, rc) \
+do { \
+ buf_dst = (u8 *)buf_dst + rc; \
+ encoded_bytes += rc; \
+ tlv_len += rc; \
+ temp_si = temp_si + 1; \
+ encode_tlv = 1; \
+} while (0)
+
+#define UPDATE_DECODE_VARIABLES(buf_src, decoded_bytes, rc) \
+do { \
+ buf_src = (u8 *)buf_src + rc; \
+ decoded_bytes += rc; \
+} while (0)
+
+#define TLV_LEN_SIZE sizeof(u16)
+#define TLV_TYPE_SIZE sizeof(u8)
+#define OPTIONAL_TLV_TYPE_START 0x10
+
+static int qmi_encode(struct qmi_elem_info *ei_array, void *out_buf,
+ const void *in_c_struct, u32 out_buf_len,
+ int enc_level);
+
+static int qmi_decode(struct qmi_elem_info *ei_array, void *out_c_struct,
+ const void *in_buf, u32 in_buf_len, int dec_level);
+
+/**
+ * skip_to_next_elem() - Skip to next element in the structure to be encoded
+ * @ei_array: Struct info describing the element to be skipped.
+ * @level: Depth level of encoding/decoding to identify nested structures.
+ *
+ * This function is used while encoding optional elements. If the flag
+ * corresponding to an optional element is not set, then encoding the
+ * optional element can be skipped. This function can be used to perform
+ * that operation.
+ *
+ * Return: struct info of the next element that can be encoded.
+ */
+static struct qmi_elem_info *skip_to_next_elem(struct qmi_elem_info *ei_array,
+ int level)
+{
+ struct qmi_elem_info *temp_ei = ei_array;
+ u8 tlv_type;
+
+ if (level > 1) {
+ temp_ei = temp_ei + 1;
+ } else {
+ do {
+ tlv_type = temp_ei->tlv_type;
+ temp_ei = temp_ei + 1;
+ } while (tlv_type == temp_ei->tlv_type);
+ }
+
+ return temp_ei;
+}
+
+/**
+ * qmi_calc_min_msg_len() - Calculate the minimum length of a QMI message
+ * @ei_array: Struct info array describing the structure.
+ * @level: Level to identify the depth of the nested structures.
+ *
+ * Return: Expected minimum length of the QMI message or 0 on error.
+ */
+static int qmi_calc_min_msg_len(struct qmi_elem_info *ei_array,
+ int level)
+{
+ int min_msg_len = 0;
+ struct qmi_elem_info *temp_ei = ei_array;
+
+ if (!ei_array)
+ return min_msg_len;
+
+ while (temp_ei->data_type != QMI_EOTI) {
+ /* Optional elements do not count in minimum length */
+ if (temp_ei->data_type == QMI_OPT_FLAG) {
+ temp_ei = skip_to_next_elem(temp_ei, level);
+ continue;
+ }
+
+ if (temp_ei->data_type == QMI_DATA_LEN) {
+ min_msg_len += (temp_ei->elem_size == sizeof(u8) ?
+ sizeof(u8) : sizeof(u16));
+ temp_ei++;
+ continue;
+ } else if (temp_ei->data_type == QMI_STRUCT) {
+ min_msg_len += qmi_calc_min_msg_len(temp_ei->ei_array,
+ (level + 1));
+ temp_ei++;
+ } else if (temp_ei->data_type == QMI_STRING) {
+ if (level > 1)
+ min_msg_len += temp_ei->elem_len <= U8_MAX ?
+ sizeof(u8) : sizeof(u16);
+ min_msg_len += temp_ei->elem_len * temp_ei->elem_size;
+ temp_ei++;
+ } else {
+ min_msg_len += (temp_ei->elem_len * temp_ei->elem_size);
+ temp_ei++;
+ }
+
+ /*
+ * Type & Length info. not prepended for elements in the
+ * nested structure.
+ */
+ if (level == 1)
+ min_msg_len += (TLV_TYPE_SIZE + TLV_LEN_SIZE);
+ }
+
+ return min_msg_len;
+}
+
+/**
+ * qmi_encode_basic_elem() - Encodes elements of basic/primary data type
+ * @buf_dst: Buffer to store the encoded information.
+ * @buf_src: Buffer containing the elements to be encoded.
+ * @elem_len: Number of elements, in the buf_src, to be encoded.
+ * @elem_size: Size of a single instance of the element to be encoded.
+ *
+ * This function encodes the "elem_len" number of data elements, each of
+ * size "elem_size" bytes from the source buffer "buf_src" and stores the
+ * encoded information in the destination buffer "buf_dst". The elements are
+ * of primary data type which include u8 - u64 or similar. This
+ * function returns the number of bytes of encoded information.
+ *
+ * Return: The number of bytes of encoded information.
+ */
+static int qmi_encode_basic_elem(void *buf_dst, const void *buf_src,
+ u32 elem_len, u32 elem_size)
+{
+ u32 i, rc = 0;
+
+ for (i = 0; i < elem_len; i++) {
+ QMI_ENCDEC_ENCODE_N_BYTES(buf_dst, buf_src, elem_size);
+ rc += elem_size;
+ }
+
+ return rc;
+}
+
+/**
+ * qmi_encode_struct_elem() - Encodes elements of struct data type
+ * @ei_array: Struct info array descibing the struct element.
+ * @buf_dst: Buffer to store the encoded information.
+ * @buf_src: Buffer containing the elements to be encoded.
+ * @elem_len: Number of elements, in the buf_src, to be encoded.
+ * @out_buf_len: Available space in the encode buffer.
+ * @enc_level: Depth of the nested structure from the main structure.
+ *
+ * This function encodes the "elem_len" number of struct elements, each of
+ * size "ei_array->elem_size" bytes from the source buffer "buf_src" and
+ * stores the encoded information in the destination buffer "buf_dst". The
+ * elements are of struct data type which includes any C structure. This
+ * function returns the number of bytes of encoded information.
+ *
+ * Return: The number of bytes of encoded information on success or negative
+ * errno on error.
+ */
+static int qmi_encode_struct_elem(struct qmi_elem_info *ei_array,
+ void *buf_dst, const void *buf_src,
+ u32 elem_len, u32 out_buf_len,
+ int enc_level)
+{
+ int i, rc, encoded_bytes = 0;
+ struct qmi_elem_info *temp_ei = ei_array;
+
+ for (i = 0; i < elem_len; i++) {
+ rc = qmi_encode(temp_ei->ei_array, buf_dst, buf_src,
+ out_buf_len - encoded_bytes, enc_level);
+ if (rc < 0) {
+ pr_err("%s: STRUCT Encode failure\n", __func__);
+ return rc;
+ }
+ buf_dst = buf_dst + rc;
+ buf_src = buf_src + temp_ei->elem_size;
+ encoded_bytes += rc;
+ }
+
+ return encoded_bytes;
+}
+
+/**
+ * qmi_encode_string_elem() - Encodes elements of string data type
+ * @ei_array: Struct info array descibing the string element.
+ * @buf_dst: Buffer to store the encoded information.
+ * @buf_src: Buffer containing the elements to be encoded.
+ * @out_buf_len: Available space in the encode buffer.
+ * @enc_level: Depth of the string element from the main structure.
+ *
+ * This function encodes a string element of maximum length "ei_array->elem_len"
+ * bytes from the source buffer "buf_src" and stores the encoded information in
+ * the destination buffer "buf_dst". This function returns the number of bytes
+ * of encoded information.
+ *
+ * Return: The number of bytes of encoded information on success or negative
+ * errno on error.
+ */
+static int qmi_encode_string_elem(struct qmi_elem_info *ei_array,
+ void *buf_dst, const void *buf_src,
+ u32 out_buf_len, int enc_level)
+{
+ int rc;
+ int encoded_bytes = 0;
+ struct qmi_elem_info *temp_ei = ei_array;
+ u32 string_len = 0;
+ u32 string_len_sz = 0;
+
+ string_len = strlen(buf_src);
+ string_len_sz = temp_ei->elem_len <= U8_MAX ?
+ sizeof(u8) : sizeof(u16);
+ if (string_len > temp_ei->elem_len) {
+ pr_err("%s: String to be encoded is longer - %d > %d\n",
+ __func__, string_len, temp_ei->elem_len);
+ return -EINVAL;
+ }
+
+ if (enc_level == 1) {
+ if (string_len + TLV_LEN_SIZE + TLV_TYPE_SIZE >
+ out_buf_len) {
+ pr_err("%s: Output len %d > Out Buf len %d\n",
+ __func__, string_len, out_buf_len);
+ return -ETOOSMALL;
+ }
+ } else {
+ if (string_len + string_len_sz > out_buf_len) {
+ pr_err("%s: Output len %d > Out Buf len %d\n",
+ __func__, string_len, out_buf_len);
+ return -ETOOSMALL;
+ }
+ rc = qmi_encode_basic_elem(buf_dst, &string_len,
+ 1, string_len_sz);
+ encoded_bytes += rc;
+ }
+
+ rc = qmi_encode_basic_elem(buf_dst + encoded_bytes, buf_src,
+ string_len, temp_ei->elem_size);
+ encoded_bytes += rc;
+
+ return encoded_bytes;
+}
+
+/**
+ * qmi_encode() - Core Encode Function
+ * @ei_array: Struct info array describing the structure to be encoded.
+ * @out_buf: Buffer to hold the encoded QMI message.
+ * @in_c_struct: Pointer to the C structure to be encoded.
+ * @out_buf_len: Available space in the encode buffer.
+ * @enc_level: Encode level to indicate the depth of the nested structure,
+ * within the main structure, being encoded.
+ *
+ * Return: The number of bytes of encoded information on success or negative
+ * errno on error.
+ */
+static int qmi_encode(struct qmi_elem_info *ei_array, void *out_buf,
+ const void *in_c_struct, u32 out_buf_len,
+ int enc_level)
+{
+ struct qmi_elem_info *temp_ei = ei_array;
+ u8 opt_flag_value = 0;
+ u32 data_len_value = 0, data_len_sz;
+ u8 *buf_dst = (u8 *)out_buf;
+ u8 *tlv_pointer;
+ u32 tlv_len;
+ u8 tlv_type;
+ u32 encoded_bytes = 0;
+ const void *buf_src;
+ int encode_tlv = 0;
+ int rc;
+
+ if (!ei_array)
+ return 0;
+
+ tlv_pointer = buf_dst;
+ tlv_len = 0;
+ if (enc_level == 1)
+ buf_dst = buf_dst + (TLV_LEN_SIZE + TLV_TYPE_SIZE);
+
+ while (temp_ei->data_type != QMI_EOTI) {
+ buf_src = in_c_struct + temp_ei->offset;
+ tlv_type = temp_ei->tlv_type;
+
+ if (temp_ei->array_type == NO_ARRAY) {
+ data_len_value = 1;
+ } else if (temp_ei->array_type == STATIC_ARRAY) {
+ data_len_value = temp_ei->elem_len;
+ } else if (data_len_value <= 0 ||
+ temp_ei->elem_len < data_len_value) {
+ pr_err("%s: Invalid data length\n", __func__);
+ return -EINVAL;
+ }
+
+ switch (temp_ei->data_type) {
+ case QMI_OPT_FLAG:
+ rc = qmi_encode_basic_elem(&opt_flag_value, buf_src,
+ 1, sizeof(u8));
+ if (opt_flag_value)
+ temp_ei = temp_ei + 1;
+ else
+ temp_ei = skip_to_next_elem(temp_ei, enc_level);
+ break;
+
+ case QMI_DATA_LEN:
+ memcpy(&data_len_value, buf_src, temp_ei->elem_size);
+ data_len_sz = temp_ei->elem_size == sizeof(u8) ?
+ sizeof(u8) : sizeof(u16);
+ /* Check to avoid out of range buffer access */
+ if ((data_len_sz + encoded_bytes + TLV_LEN_SIZE +
+ TLV_TYPE_SIZE) > out_buf_len) {
+ pr_err("%s: Too Small Buffer @DATA_LEN\n",
+ __func__);
+ return -ETOOSMALL;
+ }
+ rc = qmi_encode_basic_elem(buf_dst, &data_len_value,
+ 1, data_len_sz);
+ UPDATE_ENCODE_VARIABLES(temp_ei, buf_dst,
+ encoded_bytes, tlv_len,
+ encode_tlv, rc);
+ if (!data_len_value)
+ temp_ei = skip_to_next_elem(temp_ei, enc_level);
+ else
+ encode_tlv = 0;
+ break;
+
+ case QMI_UNSIGNED_1_BYTE:
+ case QMI_UNSIGNED_2_BYTE:
+ case QMI_UNSIGNED_4_BYTE:
+ case QMI_UNSIGNED_8_BYTE:
+ case QMI_SIGNED_2_BYTE_ENUM:
+ case QMI_SIGNED_4_BYTE_ENUM:
+ /* Check to avoid out of range buffer access */
+ if (((data_len_value * temp_ei->elem_size) +
+ encoded_bytes + TLV_LEN_SIZE + TLV_TYPE_SIZE) >
+ out_buf_len) {
+ pr_err("%s: Too Small Buffer @data_type:%d\n",
+ __func__, temp_ei->data_type);
+ return -ETOOSMALL;
+ }
+ rc = qmi_encode_basic_elem(buf_dst, buf_src,
+ data_len_value,
+ temp_ei->elem_size);
+ UPDATE_ENCODE_VARIABLES(temp_ei, buf_dst,
+ encoded_bytes, tlv_len,
+ encode_tlv, rc);
+ break;
+
+ case QMI_STRUCT:
+ rc = qmi_encode_struct_elem(temp_ei, buf_dst, buf_src,
+ data_len_value,
+ out_buf_len - encoded_bytes,
+ enc_level + 1);
+ if (rc < 0)
+ return rc;
+ UPDATE_ENCODE_VARIABLES(temp_ei, buf_dst,
+ encoded_bytes, tlv_len,
+ encode_tlv, rc);
+ break;
+
+ case QMI_STRING:
+ rc = qmi_encode_string_elem(temp_ei, buf_dst, buf_src,
+ out_buf_len - encoded_bytes,
+ enc_level);
+ if (rc < 0)
+ return rc;
+ UPDATE_ENCODE_VARIABLES(temp_ei, buf_dst,
+ encoded_bytes, tlv_len,
+ encode_tlv, rc);
+ break;
+ default:
+ pr_err("%s: Unrecognized data type\n", __func__);
+ return -EINVAL;
+ }
+
+ if (encode_tlv && enc_level == 1) {
+ QMI_ENCDEC_ENCODE_TLV(tlv_type, tlv_len, tlv_pointer);
+ encoded_bytes += (TLV_TYPE_SIZE + TLV_LEN_SIZE);
+ tlv_pointer = buf_dst;
+ tlv_len = 0;
+ buf_dst = buf_dst + TLV_LEN_SIZE + TLV_TYPE_SIZE;
+ encode_tlv = 0;
+ }
+ }
+
+ return encoded_bytes;
+}
+
+/**
+ * qmi_decode_basic_elem() - Decodes elements of basic/primary data type
+ * @buf_dst: Buffer to store the decoded element.
+ * @buf_src: Buffer containing the elements in QMI wire format.
+ * @elem_len: Number of elements to be decoded.
+ * @elem_size: Size of a single instance of the element to be decoded.
+ *
+ * This function decodes the "elem_len" number of elements in QMI wire format,
+ * each of size "elem_size" bytes from the source buffer "buf_src" and stores
+ * the decoded elements in the destination buffer "buf_dst". The elements are
+ * of primary data type which include u8 - u64 or similar. This
+ * function returns the number of bytes of decoded information.
+ *
+ * Return: The total size of the decoded data elements, in bytes.
+ */
+static int qmi_decode_basic_elem(void *buf_dst, const void *buf_src,
+ u32 elem_len, u32 elem_size)
+{
+ u32 i, rc = 0;
+
+ for (i = 0; i < elem_len; i++) {
+ QMI_ENCDEC_DECODE_N_BYTES(buf_dst, buf_src, elem_size);
+ rc += elem_size;
+ }
+
+ return rc;
+}
+
+/**
+ * qmi_decode_struct_elem() - Decodes elements of struct data type
+ * @ei_array: Struct info array descibing the struct element.
+ * @buf_dst: Buffer to store the decoded element.
+ * @buf_src: Buffer containing the elements in QMI wire format.
+ * @elem_len: Number of elements to be decoded.
+ * @tlv_len: Total size of the encoded inforation corresponding to
+ * this struct element.
+ * @dec_level: Depth of the nested structure from the main structure.
+ *
+ * This function decodes the "elem_len" number of elements in QMI wire format,
+ * each of size "(tlv_len/elem_len)" bytes from the source buffer "buf_src"
+ * and stores the decoded elements in the destination buffer "buf_dst". The
+ * elements are of struct data type which includes any C structure. This
+ * function returns the number of bytes of decoded information.
+ *
+ * Return: The total size of the decoded data elements on success, negative
+ * errno on error.
+ */
+static int qmi_decode_struct_elem(struct qmi_elem_info *ei_array,
+ void *buf_dst, const void *buf_src,
+ u32 elem_len, u32 tlv_len,
+ int dec_level)
+{
+ int i, rc, decoded_bytes = 0;
+ struct qmi_elem_info *temp_ei = ei_array;
+
+ for (i = 0; i < elem_len && decoded_bytes < tlv_len; i++) {
+ rc = qmi_decode(temp_ei->ei_array, buf_dst, buf_src,
+ tlv_len - decoded_bytes, dec_level);
+ if (rc < 0)
+ return rc;
+ buf_src = buf_src + rc;
+ buf_dst = buf_dst + temp_ei->elem_size;
+ decoded_bytes += rc;
+ }
+
+ if ((dec_level <= 2 && decoded_bytes != tlv_len) ||
+ (dec_level > 2 && (i < elem_len || decoded_bytes > tlv_len))) {
+ pr_err("%s: Fault in decoding: dl(%d), db(%d), tl(%d), i(%d), el(%d)\n",
+ __func__, dec_level, decoded_bytes, tlv_len,
+ i, elem_len);
+ return -EFAULT;
+ }
+
+ return decoded_bytes;
+}
+
+/**
+ * qmi_decode_string_elem() - Decodes elements of string data type
+ * @ei_array: Struct info array descibing the string element.
+ * @buf_dst: Buffer to store the decoded element.
+ * @buf_src: Buffer containing the elements in QMI wire format.
+ * @tlv_len: Total size of the encoded inforation corresponding to
+ * this string element.
+ * @dec_level: Depth of the string element from the main structure.
+ *
+ * This function decodes the string element of maximum length
+ * "ei_array->elem_len" from the source buffer "buf_src" and puts it into
+ * the destination buffer "buf_dst". This function returns number of bytes
+ * decoded from the input buffer.
+ *
+ * Return: The total size of the decoded data elements on success, negative
+ * errno on error.
+ */
+static int qmi_decode_string_elem(struct qmi_elem_info *ei_array,
+ void *buf_dst, const void *buf_src,
+ u32 tlv_len, int dec_level)
+{
+ int rc;
+ int decoded_bytes = 0;
+ u32 string_len = 0;
+ u32 string_len_sz = 0;
+ struct qmi_elem_info *temp_ei = ei_array;
+
+ if (dec_level == 1) {
+ string_len = tlv_len;
+ } else {
+ string_len_sz = temp_ei->elem_len <= U8_MAX ?
+ sizeof(u8) : sizeof(u16);
+ rc = qmi_decode_basic_elem(&string_len, buf_src,
+ 1, string_len_sz);
+ decoded_bytes += rc;
+ }
+
+ if (string_len > temp_ei->elem_len) {
+ pr_err("%s: String len %d > Max Len %d\n",
+ __func__, string_len, temp_ei->elem_len);
+ return -ETOOSMALL;
+ } else if (string_len > tlv_len) {
+ pr_err("%s: String len %d > Input Buffer Len %d\n",
+ __func__, string_len, tlv_len);
+ return -EFAULT;
+ }
+
+ rc = qmi_decode_basic_elem(buf_dst, buf_src + decoded_bytes,
+ string_len, temp_ei->elem_size);
+ *((char *)buf_dst + string_len) = '\0';
+ decoded_bytes += rc;
+
+ return decoded_bytes;
+}
+
+/**
+ * find_ei() - Find element info corresponding to TLV Type
+ * @ei_array: Struct info array of the message being decoded.
+ * @type: TLV Type of the element being searched.
+ *
+ * Every element that got encoded in the QMI message will have a type
+ * information associated with it. While decoding the QMI message,
+ * this function is used to find the struct info regarding the element
+ * that corresponds to the type being decoded.
+ *
+ * Return: Pointer to struct info, if found
+ */
+static struct qmi_elem_info *find_ei(struct qmi_elem_info *ei_array,
+ u32 type)
+{
+ struct qmi_elem_info *temp_ei = ei_array;
+
+ while (temp_ei->data_type != QMI_EOTI) {
+ if (temp_ei->tlv_type == (u8)type)
+ return temp_ei;
+ temp_ei = temp_ei + 1;
+ }
+
+ return NULL;
+}
+
+/**
+ * qmi_decode() - Core Decode Function
+ * @ei_array: Struct info array describing the structure to be decoded.
+ * @out_c_struct: Buffer to hold the decoded C struct
+ * @in_buf: Buffer containing the QMI message to be decoded
+ * @in_buf_len: Length of the QMI message to be decoded
+ * @dec_level: Decode level to indicate the depth of the nested structure,
+ * within the main structure, being decoded
+ *
+ * Return: The number of bytes of decoded information on success, negative
+ * errno on error.
+ */
+static int qmi_decode(struct qmi_elem_info *ei_array, void *out_c_struct,
+ const void *in_buf, u32 in_buf_len,
+ int dec_level)
+{
+ struct qmi_elem_info *temp_ei = ei_array;
+ u8 opt_flag_value = 1;
+ u32 data_len_value = 0, data_len_sz = 0;
+ u8 *buf_dst = out_c_struct;
+ const u8 *tlv_pointer;
+ u32 tlv_len = 0;
+ u32 tlv_type;
+ u32 decoded_bytes = 0;
+ const void *buf_src = in_buf;
+ int rc;
+
+ while (decoded_bytes < in_buf_len) {
+ if (dec_level >= 2 && temp_ei->data_type == QMI_EOTI)
+ return decoded_bytes;
+
+ if (dec_level == 1) {
+ tlv_pointer = buf_src;
+ QMI_ENCDEC_DECODE_TLV(&tlv_type,
+ &tlv_len, tlv_pointer);
+ buf_src += (TLV_TYPE_SIZE + TLV_LEN_SIZE);
+ decoded_bytes += (TLV_TYPE_SIZE + TLV_LEN_SIZE);
+ temp_ei = find_ei(ei_array, tlv_type);
+ if (!temp_ei && tlv_type < OPTIONAL_TLV_TYPE_START) {
+ pr_err("%s: Inval element info\n", __func__);
+ return -EINVAL;
+ } else if (!temp_ei) {
+ UPDATE_DECODE_VARIABLES(buf_src,
+ decoded_bytes, tlv_len);
+ continue;
+ }
+ } else {
+ /*
+ * No length information for elements in nested
+ * structures. So use remaining decodable buffer space.
+ */
+ tlv_len = in_buf_len - decoded_bytes;
+ }
+
+ buf_dst = out_c_struct + temp_ei->offset;
+ if (temp_ei->data_type == QMI_OPT_FLAG) {
+ memcpy(buf_dst, &opt_flag_value, sizeof(u8));
+ temp_ei = temp_ei + 1;
+ buf_dst = out_c_struct + temp_ei->offset;
+ }
+
+ if (temp_ei->data_type == QMI_DATA_LEN) {
+ data_len_sz = temp_ei->elem_size == sizeof(u8) ?
+ sizeof(u8) : sizeof(u16);
+ rc = qmi_decode_basic_elem(&data_len_value, buf_src,
+ 1, data_len_sz);
+ memcpy(buf_dst, &data_len_value, sizeof(u32));
+ temp_ei = temp_ei + 1;
+ buf_dst = out_c_struct + temp_ei->offset;
+ tlv_len -= data_len_sz;
+ UPDATE_DECODE_VARIABLES(buf_src, decoded_bytes, rc);
+ }
+
+ if (temp_ei->array_type == NO_ARRAY) {
+ data_len_value = 1;
+ } else if (temp_ei->array_type == STATIC_ARRAY) {
+ data_len_value = temp_ei->elem_len;
+ } else if (data_len_value > temp_ei->elem_len) {
+ pr_err("%s: Data len %d > max spec %d\n",
+ __func__, data_len_value, temp_ei->elem_len);
+ return -ETOOSMALL;
+ }
+
+ switch (temp_ei->data_type) {
+ case QMI_UNSIGNED_1_BYTE:
+ case QMI_UNSIGNED_2_BYTE:
+ case QMI_UNSIGNED_4_BYTE:
+ case QMI_UNSIGNED_8_BYTE:
+ case QMI_SIGNED_2_BYTE_ENUM:
+ case QMI_SIGNED_4_BYTE_ENUM:
+ rc = qmi_decode_basic_elem(buf_dst, buf_src,
+ data_len_value,
+ temp_ei->elem_size);
+ UPDATE_DECODE_VARIABLES(buf_src, decoded_bytes, rc);
+ break;
+
+ case QMI_STRUCT:
+ rc = qmi_decode_struct_elem(temp_ei, buf_dst, buf_src,
+ data_len_value, tlv_len,
+ dec_level + 1);
+ if (rc < 0)
+ return rc;
+ UPDATE_DECODE_VARIABLES(buf_src, decoded_bytes, rc);
+ break;
+
+ case QMI_STRING:
+ rc = qmi_decode_string_elem(temp_ei, buf_dst, buf_src,
+ tlv_len, dec_level);
+ if (rc < 0)
+ return rc;
+ UPDATE_DECODE_VARIABLES(buf_src, decoded_bytes, rc);
+ break;
+
+ default:
+ pr_err("%s: Unrecognized data type\n", __func__);
+ return -EINVAL;
+ }
+ temp_ei = temp_ei + 1;
+ }
+
+ return decoded_bytes;
+}
+
+/**
+ * qmi_encode_message() - Encode C structure as QMI encoded message
+ * @type: Type of QMI message
+ * @msg_id: Message ID of the message
+ * @len: Passed as max length of the message, updated to actual size
+ * @txn_id: Transaction ID
+ * @ei: QMI message descriptor
+ * @c_struct: Reference to structure to encode
+ *
+ * Return: Buffer with encoded message, or negative ERR_PTR() on error
+ */
+void *qmi_encode_message(int type, unsigned int msg_id, size_t *len,
+ unsigned int txn_id, struct qmi_elem_info *ei,
+ const void *c_struct)
+{
+ struct qmi_header *hdr;
+ ssize_t msglen = 0;
+ void *msg;
+ int ret;
+
+ /* Check the possibility of a zero length QMI message */
+ if (!c_struct) {
+ ret = qmi_calc_min_msg_len(ei, 1);
+ if (ret) {
+ pr_err("%s: Calc. len %d != 0, but NULL c_struct\n",
+ __func__, ret);
+ return ERR_PTR(-EINVAL);
+ }
+ }
+
+ msg = kzalloc(sizeof(*hdr) + *len, GFP_KERNEL);
+ if (!msg)
+ return ERR_PTR(-ENOMEM);
+
+ /* Encode message, if we have a message */
+ if (c_struct) {
+ msglen = qmi_encode(ei, msg + sizeof(*hdr), c_struct, *len, 1);
+ if (msglen < 0) {
+ kfree(msg);
+ return ERR_PTR(msglen);
+ }
+ }
+
+ hdr = msg;
+ hdr->type = type;
+ hdr->txn_id = txn_id;
+ hdr->msg_id = msg_id;
+ hdr->msg_len = msglen;
+
+ *len = sizeof(*hdr) + msglen;
+
+ return msg;
+}
+EXPORT_SYMBOL(qmi_encode_message);
+
+/**
+ * qmi_decode_message() - Decode QMI encoded message to C structure
+ * @buf: Buffer with encoded message
+ * @len: Amount of data in @buf
+ * @ei: QMI message descriptor
+ * @c_struct: Reference to structure to decode into
+ *
+ * Return: The number of bytes of decoded information on success, negative
+ * errno on error.
+ */
+int qmi_decode_message(const void *buf, size_t len,
+ struct qmi_elem_info *ei, void *c_struct)
+{
+ if (!ei)
+ return -EINVAL;
+
+ if (!c_struct || !buf || !len)
+ return -EINVAL;
+
+ return qmi_decode(ei, c_struct, buf + sizeof(struct qmi_header),
+ len - sizeof(struct qmi_header), 1);
+}
+EXPORT_SYMBOL(qmi_decode_message);
+
+/* Common header in all QMI responses */
+struct qmi_elem_info qmi_response_type_v01_ei[] = {
+ {
+ .data_type = QMI_SIGNED_2_BYTE_ENUM,
+ .elem_len = 1,
+ .elem_size = sizeof(u16),
+ .array_type = NO_ARRAY,
+ .tlv_type = QMI_COMMON_TLV_TYPE,
+ .offset = offsetof(struct qmi_response_type_v01, result),
+ .ei_array = NULL,
+ },
+ {
+ .data_type = QMI_SIGNED_2_BYTE_ENUM,
+ .elem_len = 1,
+ .elem_size = sizeof(u16),
+ .array_type = NO_ARRAY,
+ .tlv_type = QMI_COMMON_TLV_TYPE,
+ .offset = offsetof(struct qmi_response_type_v01, error),
+ .ei_array = NULL,
+ },
+ {
+ .data_type = QMI_EOTI,
+ .elem_len = 0,
+ .elem_size = 0,
+ .array_type = NO_ARRAY,
+ .tlv_type = QMI_COMMON_TLV_TYPE,
+ .offset = 0,
+ .ei_array = NULL,
+ },
+};
+EXPORT_SYMBOL(qmi_response_type_v01_ei);
+
+MODULE_DESCRIPTION("QMI encoder/decoder helper");
+MODULE_LICENSE("GPL v2");

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