Shared Memory

  • A small module that can manage a list of pre-allocaed memory pools so that multiple modules can use them in non-overlapping manner.

Usage

  1. All API functions have the first argument configuration of framer.

  2. Use rs_shm_init to initialize the logic

  3. Use rs_shm_add to create an entry

  4. Use rs_shm_request to request a shared memory

5. Use the memory and then release it using rs_shm_release 4. Return codes of API functions are defined in header file.

Can DBC framer calls

Function

Description

rs_shm_init

Function to initialize the shared memory manager

rs_shm_add

Function to add a memory to the shared memory pool

rs_shm_request

Function to request shared memory with given ID

rs_shm_release

Function to release shared memory with given ID

Error Code

  • Every API’s for the message queue module returns some success or failure values.

Please refer below section,

Shared Memory Header Details

Documentation from the relevant header as follows:

Shared Memorry Specific APIs.

Defines macros and functions specific to shared memory functionality

Author

Embien RAPIDSEA Team

Copyright

Embien Technologies India Pvt. Ltd.

Defines

RS_SHM_MAX_NUM_POOLS

Typedefs

typedef struct tag_rs_shm_info rs_shm_info_t

Structure for each shared memory information.

Functions

rs_ret_val_t rs_shm_init()

Initializes the shared memory pool.

This function initializes internal parameters associated with shared memory.

Returns:

return 0 for success

rs_ret_val_t rs_shm_add(uint8_t u8_shm_id, void *ptr_buf, uint32_t u32_buf_len)

Adds the given shared memory to the pool.

This function adds the given buffer and matches it to the shared memory id given.

Parameters:

  • u8_shm_id – [in] - Shared memory ID

  • ptr_buf – [in] - Pointer to the buffer allocated

  • u32_buf_len – [in] - Size of the buffer.

Returns:

return 0 for success or error code on failure

void *rs_shm_request(uint8_t u8_shm_id, uint8_t u8_requestor_id)

Requests the shared memory corresponding to the given requester ID.

This function checks if the given shared memory ID is free and returns the base pointer.

Parameters:

  • u8_shm_id – [in] - Shared memory ID

  • u8_requestor_id – [in] - Requester ID

Returns:

return shared memory pointer on success or NULL

rs_ret_val_t rs_shm_release(uint8_t u8_shm_id, uint8_t u8_requestor_id)

Releases the shared memory ID already held by requester.

This function releases the shared memory that is currently being held by the requester.

Parameters:

  • u8_shm_id – [in] - Shared memory ID

  • u8_requestor_id – [in] - Requester ID

Returns:

return 0 for success or error code

struct tag_rs_shm_info
#include <rs_shm.h>

Structure for each shared memory information.

Public Members

uint8_t shm_id

Shared memory ID.

uint8_t owner_id

Current Owner of the memory.

void *ptr_buf

Memory location.

uint32_t buf_len

Size of the buffer.