Memory pool

nRF5 SDK v12.1.0
Modules | Functions

Memory pool implementation. More...

Modules

memory pool implementation used by HCI configuration

Functions

uint32_t hci_mem_pool_open (void)
Function for opening the module. More...
uint32_t hci_mem_pool_close (void)
Function for closing the module. More...
uint32_t hci_mem_pool_tx_alloc (void **pp_buffer)
Function for allocating requested amount of TX memory. More...
uint32_t hci_mem_pool_tx_free (void)
Function for freeing previously allocated TX memory. More...
uint32_t hci_mem_pool_rx_produce (uint32_t length, void **pp_buffer)
Function for producing a free RX memory block for usage. More...
uint32_t hci_mem_pool_rx_data_size_set (uint32_t length)
Function for setting the length of the last produced RX memory block. More...
uint32_t hci_mem_pool_rx_extract (uint8_t **pp_buffer, uint32_t *p_length)
Function for extracting a packet, which has been filled with read data, for further processing. More...
uint32_t hci_mem_pool_rx_consume (uint8_t *p_buffer)
Function for freeing previously extracted packet, which has been filled with read data. More...

Detailed Description

Memory pool implementation.

Memory pool implementation, based on circular buffer data structure, which supports asynchronous processing of RX data. The current default implementation supports 1 TX buffer and 4 RX buffers. The memory managed by the pool is allocated from static storage instead of heap. The internal design of the circular buffer implementing the RX memory layout is illustrated in the picture below.

Page-1 Flowline1 free(consume) free(consume) Flowline1.266 read(extract) read(extract) Flowline1.267 write(produce) write(produce) Flowline1.268 Older data Older data Flowline1.269 Newer data Newer data Process.277 Sheet.278 unused space unused space Sheet.281 unused space unused space Sheet.282 Data being used by transport Data being used by transport Sheet.285 Data being used by application Data being used by application Sheet.286 Sheet.287 Sheet.288
Circular buffer design

The expected call order for the RX APIs is as follows:

  • hci_mem_pool_rx_produce
  • hci_mem_pool_rx_data_size_set
  • hci_mem_pool_rx_extract
  • hci_mem_pool_rx_consume
Warning
If the above mentioned expected call order is violated the end result can be undefined.
Component specific configuration options

The following compile time configuration options are available to suit various implementations:

  • TX_BUF_SIZE TX buffer size in bytes.
  • RX_BUF_SIZE RX buffer size in bytes.
  • RX_BUF_QUEUE_SIZE RX buffer element size.

Function Documentation

uint32_t hci_mem_pool_close ( void )

Function for closing the module.

Return values
NRF_SUCCESS Operation success.
uint32_t hci_mem_pool_open ( void )

Function for opening the module.

Return values
NRF_SUCCESS Operation success.
uint32_t hci_mem_pool_rx_consume ( uint8_t * p_buffer )

Function for freeing previously extracted packet, which has been filled with read data.

Parameters
[in] p_buffer Pointer to consumed buffer.
Return values
NRF_SUCCESS Operation success.
NRF_ERROR_NO_MEM Operation failure. No packet available to free.
NRF_ERROR_INVALID_ADDR Operation failure. Not a valid pointer.
uint32_t hci_mem_pool_rx_data_size_set ( uint32_t length )

Function for setting the length of the last produced RX memory block.

Warning
If call to this API is omitted the end result is that the following call to mem_pool_rx_extract will return incorrect data in the p_length output parameter.
Parameters
[in] length Amount, in bytes, of actual memory used.
Return values
NRF_SUCCESS Operation success. Length was set.
uint32_t hci_mem_pool_rx_extract ( uint8_t ** pp_buffer ,
uint32_t * p_length
)

Function for extracting a packet, which has been filled with read data, for further processing.

Parameters
[out] pp_buffer Pointer to the packet data.
[out] p_length Length of packet data in bytes.
Return values
NRF_SUCCESS Operation success.
NRF_ERROR_NO_MEM Operation failure. No packet available to extract.
NRF_ERROR_NULL Operation failure. NULL pointer supplied.
uint32_t hci_mem_pool_rx_produce ( uint32_t length ,
void ** pp_buffer
)

Function for producing a free RX memory block for usage.

Note
Upon produce request amount being 0, NRF_SUCCESS is returned.
Parameters
[in] length Amount, in bytes, of free memory to be produced.
[out] pp_buffer Pointer to the allocated memory.
Return values
NRF_SUCCESS Operation success. Free RX memory block produced.
NRF_ERROR_NO_MEM Operation failure. No suitable memory available for allocation.
NRF_ERROR_DATA_SIZE Operation failure. Request size exceeds limit.
NRF_ERROR_NULL Operation failure. NULL pointer supplied.
uint32_t hci_mem_pool_tx_alloc ( void ** pp_buffer )

Function for allocating requested amount of TX memory.

Parameters
[out] pp_buffer Pointer to the allocated memory.
Return values
NRF_SUCCESS Operation success. Memory was allocated.
NRF_ERROR_NO_MEM Operation failure. No memory available for allocation.
NRF_ERROR_NULL Operation failure. NULL pointer supplied.
uint32_t hci_mem_pool_tx_free ( void )

Function for freeing previously allocated TX memory.

Note
Memory management follows the FIFO principle meaning that free() order must match the alloc(...) order, which is the reason for omitting exact memory block identifier as an input parameter.
Return values
NRF_SUCCESS Operation success. Memory was freed.