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 <[email protected]>
> Tested-By: Srinivas Kandagatla <[email protected]>
> Signed-off-by: Bjorn Andersson <[email protected]>
> ---
>
> 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
On Fri 01 Dec 01:10 PST 2017, Jitendra Sharma wrote:
> Hi Bjorn,
>
Hi Jitendra,
> On 11/30/2017 6:46 AM, Bjorn Andersson wrote:
> > +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
IMHO all these sizes should be size_t and there are a few places where
we should add "const" specifier to pointers. But I refrained from
"fixing" these up in an effort to keep things as close to the downstream
implementation as possible.
If Andy agrees I'm hoping that we can take this version and then follow
up with a separate patch, making the review more explicit and make it
easier to track down any potential regressions from such a change.
Thank you for the review!
Regards,
Bjorn