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Message-ID: <6c6be375-6895-ecaf-9844-40774f6bdd5c@codeaurora.org>
Date: Fri, 1 Dec 2017 14:40:09 +0530
From: Jitendra Sharma <shajit@...eaurora.org>
To: Bjorn Andersson <bjorn.andersson@...aro.org>,
Andy Gross <andy.gross@...aro.org>,
Ohad Ben-Cohen <ohad@...ery.com>
Cc: Arun Kumar Neelakantam <aneela@...eaurora.org>,
Chris Lew <clew@...eaurora.org>, linux-kernel@...r.kernel.org,
linux-arm-msm@...r.kernel.org, linux-soc@...r.kernel.org,
linux-remoteproc@...r.kernel.org
Subject: Re: [PATCH v4 1/5] soc: qcom: Introduce QMI encoder/decoder
Hi Bjorn,
Few minor comments ..
On 11/30/2017 6:46 AM, Bjorn Andersson wrote:
> 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.
>
> Tested-By: Chris Lew <clew@...eaurora.org>
> Tested-By: Srinivas Kandagatla <srinivas.kandagatla@...aro.org>
> Signed-off-by: Bjorn Andersson <bjorn.andersson@...aro.org>
> ---
>
> Changes since v3:
> - Moved depends on ARCH_QCOM from patch 2
> - Kerneldoc updates
> - Style updates
> - Dropped qrtr.h include from header file
> - Rename is_array to array_type
>
> Changes since v2:
> - Checkpatch fixes
>
> Changes since v1:
> - None
>
> drivers/soc/qcom/Kconfig | 9 +
> drivers/soc/qcom/Makefile | 2 +
> drivers/soc/qcom/qmi_encdec.c | 826 ++++++++++++++++++++++++++++++++++++++++++
> include/linux/soc/qcom/qmi.h | 114 ++++++
> 4 files changed, 951 insertions(+)
> create mode 100644 drivers/soc/qcom/qmi_encdec.c
> create mode 100644 include/linux/soc/qcom/qmi.h
>
> diff --git a/drivers/soc/qcom/Kconfig b/drivers/soc/qcom/Kconfig
> index b81374bb6713..2411df0427d9 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..a197fc0114c3
> --- /dev/null
> +++ b/drivers/soc/qcom/qmi_encdec.c
> @@ -0,0 +1,826 @@
> +/*
> + * Copyright (c) 2012-2015, The Linux Foundation. All rights reserved.
> + * Copyright (C) 2017 Linaro Ltd.
> + *
> + * 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.
> + *
> + */
> +
> +#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;
min_msg_len should be u32 as it would not be negative
> + 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;
Function return type should not be int
> +
> + 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;
change rc,encoded_bytes to u32
> + 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;
Return type should not be int
> +
> + 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;
rc,decoded_bytes should be unsigned and change appropriate function
return type
> + 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;
same as above
> + 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");
> diff --git a/include/linux/soc/qcom/qmi.h b/include/linux/soc/qcom/qmi.h
> new file mode 100644
> index 000000000000..1b66e9a6074f
> --- /dev/null
> +++ b/include/linux/soc/qcom/qmi.h
> @@ -0,0 +1,114 @@
> +/*
> + * Copyright (c) 2012-2014, The Linux Foundation. All rights reserved.
> + * Copyright (c) 2017, Linaro Ltd.
> + *
> + * 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_HELPERS_H__
> +#define __QMI_HELPERS_H__
> +
> +#include <linux/types.h>
> +
> +/**
> + * qmi_header - wireformat header of QMI messages
> + * @type: type of message
> + * @txn_id: transaction id
> + * @msg_id: message id
> + * @msg_len: length of message payload following header
> + */
> +struct qmi_header {
> + u8 type;
> + u16 txn_id;
> + u16 msg_id;
> + u16 msg_len;
> +} __packed;
> +
> +#define QMI_REQUEST 0
> +#define QMI_RESPONSE 2
> +#define QMI_INDICATION 4
> +
> +#define QMI_COMMON_TLV_TYPE 0
> +
> +enum qmi_elem_type {
> + QMI_EOTI,
> + QMI_OPT_FLAG,
> + 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,
> +};
> +
> +enum qmi_array_type {
> + NO_ARRAY,
> + STATIC_ARRAY,
> + VAR_LEN_ARRAY,
> +};
> +
> +/**
> + * struct qmi_elem_info - describes how to encode a single QMI element
> + * @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.
> + * @array_type: Array type of this element.
> + * @tlv_type: QMI message specific type to identify which element
> + * is present in an incoming message.
> + * @offset: Specifies the offset of the first instance of this
> + * element in the data structure.
> + * @ei_array: Null-terminated array of @qmi_elem_info to describe nested
> + * structures.
> + */
> +struct qmi_elem_info {
> + enum qmi_elem_type data_type;
> + u32 elem_len;
> + u32 elem_size;
> + enum qmi_array_type array_type;
> + u8 tlv_type;
> + u32 offset;
> + struct qmi_elem_info *ei_array;
> +};
> +
> +#define QMI_RESULT_SUCCESS_V01 0
> +#define QMI_RESULT_FAILURE_V01 1
> +
> +#define QMI_ERR_NONE_V01 0
> +#define QMI_ERR_MALFORMED_MSG_V01 1
> +#define QMI_ERR_NO_MEMORY_V01 2
> +#define QMI_ERR_INTERNAL_V01 3
> +#define QMI_ERR_CLIENT_IDS_EXHAUSTED_V01 5
> +#define QMI_ERR_INVALID_ID_V01 41
> +#define QMI_ERR_ENCODING_V01 58
> +#define QMI_ERR_INCOMPATIBLE_STATE_V01 90
> +#define QMI_ERR_NOT_SUPPORTED_V01 94
> +
> +/**
> + * qmi_response_type_v01 - common response header (decoded)
> + * @result: result of the transaction
> + * @error: error value, when @result is QMI_RESULT_FAILURE_V01
> + */
> +struct qmi_response_type_v01 {
> + u16 result;
> + u16 error;
> +};
> +
> +extern struct qmi_elem_info qmi_response_type_v01_ei[];
> +
> +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);
> +
> +int qmi_decode_message(const void *buf, size_t len,
> + struct qmi_elem_info *ei, void *c_struct);
> +
> +#endif
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