Direct Memory Access#

sl_dma_transfer_type_t#

sl_dma_transfer_type_t

Enumeration holds transfer types of DMA.

sl_dma_transfer_mode_t#

sl_dma_transfer_mode_t

Enumeration holds transfer modes of DMA.

sl_dma_peripheral_ack_t#

sl_dma_peripheral_ack_t

Enumeration holds peripheral ACK signals to DMA.

sl_dma_transfer_size_t#

sl_dma_transfer_size_t

Enumeration holds DMA transfer sizes.

sl_dma_transfer_inc_t#

sl_dma_transfer_inc_t

Enumeration holds DMA transfer address increment for source and destination.

sl_dma_callback_code_t#

sl_dma_callback_code_t

Enumeration holds 8-bit codes which are used by callback_type in sl_si91x_dma_unregister_callbacks function.

sl_dma_transfer_complete#

typedef void(* sl_dma_transfer_complete) (uint32_t channel, void *data) )(uint32_t channel, void *data)

Typedef for user supplied callback function which is called when a DMA transfer completes.

sl_dma_error#

typedef void(* sl_dma_error) (uint32_t channel, void *data) )(uint32_t channel, void *data)

Typedef for user supplied callback function which is called when a DMA error occurs.

sl_channel_allocation_data_t#

sl_channel_data_t sl_channel_allocation_data_t[2][SL_CHANNEL_COUNT]

DMA driver channel allocator.

sl_si91x_dma_init#

sl_status_t sl_si91x_dma_init (sl_dma_init_t * dma_init)

This function initializes the DMA peripheral by enabling DMA clock and clearing DMA interrupts.

Configure dma_init->dma_number to 0 for initializing UDMA0 and 1 for initializing UDMA1

• Pre-conditions:

  • none

Returns

• Initialization status SL_STATUS_OK - Initialization success SL_STATUS_NOT_INITIALIZED - Initialization fail

sl_si91x_dma_deinit#

sl_status_t sl_si91x_dma_deinit (uint32_t dma_number)

This function deinitializes the DMA module by disabling peripheral clock and interrupts.

DMA will be deinitialized only if there is no ongoing transfer.

• Pre-conditions:

  • sl_si91x_dma_init

Returns

• deinitialization status SL_STATUS_OK - Deinit success SL_STATUS_BUSY - Cannot deinit the peripheral due to an ongoing transfer SL_STATUS_NOT_INITIALIZED - DMA peripheral not initialized

sl_si91x_dma_allocate_channel#

sl_status_t sl_si91x_dma_allocate_channel (uint32_t dma_number, uint32_t * channel_no, uint32_t priority)

This function checks the available DMA channel and allocates the channel.

This function also sets the priority of allocated channel and assigns the channel number to *channel_no variable. If no channel is available, it will return SL_DMA_NO_CHANNEL_AVAILABLE. Note: Users can also initialize the desired channel number and this API checks whether desired channel is available and allocates the channel if available. If users want the driver to allocate the available channel, channel_no should be initialized to 0.

• Pre-conditions:

  • sl_si91x_dma_init

Returns

• channel allocation status SL_STATUS_OK - Channel allocated SL_STATUS_DMA_NO_CHANNEL_AVAILABLE - All DMA channels are allocated SL_STATUS_DMA_CHANNEL_ALLOCATED - Desired channel is already allocated SL_STATUS_NOT_INITIALIZED - DMA peripheral not initialized SL_STATUS_INVALID_PARAMETER - Channel no is invalid

sl_si91x_dma_deallocate_channel#

sl_status_t sl_si91x_dma_deallocate_channel (uint32_t dma_number, uint32_t channel_no)

This function deallocates the DMA channel if there is no ongoing transfer on channel.
Deallocating the channel will also unregister the callbacks for transfer complete
and error.

@pre Pre-conditions:

• sl_si91x_dma_init

sl_si91x_dma_allocate_channel

Returns

• channel deallocation status SL_STATUS_OK - Channel deallocated SL_STATUS_BUSY - Cannot deallocate channel due to an ongoing transfer SL_STATUS_NOT_INITIALIZED - DMA peripheral not initialized SL_STATUS_INVALID_PARAMETER - Channel no is invalid

sl_si91x_dma_register_callbacks#

sl_status_t sl_si91x_dma_register_callbacks (uint32_t dma_number, uint32_t channel_no, sl_dma_callback_t * callback_t)

This function registers the DMA callbacks (transfer complete & error)
Users must update the sl_dma_callback_t structure and pass its address to this function.
Users can have seperate callbacks for transfer complete and error for each channel

@pre Pre-conditions:

• sl_si91x_dma_init

sl_si91x_dma_allocate_channel

Returns

• channel deallocation status SL_STATUS_OK - Callback registered successfully SL_STATUS_INVALID_PARAMETER - Invalid channel number SL_STATUS_NOT_INITIALIZED - DMA peripheral not initialized

sl_si91x_dma_unregister_callbacks#

sl_status_t sl_si91x_dma_unregister_callbacks (uint32_t dma_number, uint32_t channel_no, uint8_t callback_type)

This function unregisters the DMA callbacks (transfer complete & error)
Users need to update the 8-bit variable callback_type and pass to the function
Each bit is mapped to a specific callback.

@pre Pre-conditions:

• sl_si91x_dma_init

sl_si91x_dma_allocate_channel

• sl_si91x_dma_register_callbacks

Returns

• channel deallocation status SL_STATUS_OK - Callback unregistered successfully SL_STATUS_INVALID_PARAMETER - Invalid channel number SL_STATUS_NOT_INITIALIZED - DMA peripheral not initialized

sl_si91x_dma_transfer#

sl_status_t sl_si91x_dma_transfer (uint32_t dma_number, uint32_t channel_no, sl_dma_xfer_t * dma_transfer_t)

This function configures the DMA channel descriptor and initiate DMA transfer
DMA primary descriptor is updated in this function and based on transfer mode
alternate descriptor is updated (only for ping pong mode). Also other DMA parameters
like peripheral ACK signal (for peripheral memory transfers), DMA priority etc. are
updated in this function.

@pre Pre-conditions:

• sl_si91x_dma_init

sl_si91x_dma_allocate_channel

• sl_si91x_dma_register_callbacks

Returns

• DMA transfer status SL_STATUS_OK - Transfer started successfully SL_STATUS_SUSPENDED - Transfer initialization fail SL_STATUS_NOT_INITIALIZED - DMA peripheral not initialized SL_STATUS_INVALID_PARAMETER - Channel no is invalid

sl_si91x_dma_simple_transfer#

sl_status_t sl_si91x_dma_simple_transfer (uint32_t dma_number, uint32_t channel_no, void * src_addr, void * dst_addr, uint32_t data_size)

This function configures the DMA channel descriptor and initiate simple memory to memory
DMA transfer. Users need to pass the source address and destination address of transfer
along with transfer length in bytes.

@pre Pre-conditions:

• sl_si91x_dma_init

sl_si91x_dma_allocate_channel

• sl_si91x_dma_register_callbacks

@param[in] dma_number  dma_number  0->UDMA0, 1->UDMA1
@param[in] channel_no    (1-32) -> UDMA0
                         (1-12) -> UDMA1
@param[in] *src_addr     source address.
@param[in] *dst_addr     destination address.
@param[in] data_size     transfer size in bytes

@return DMA transfer status
        SL_STATUS_OK  - Transfer success
        SL_STATUS_SUSPENDED - Transfer initialization fail
        SL_STATUS_NOT_INITIALIZED - DMA peripheral not initialized
        SL_STATUS_INVALID_PARAMETER - Channel no is invalid

sl_si91x_dma_stop_transfer#

sl_status_t sl_si91x_dma_stop_transfer (uint32_t dma_number, uint32_t channel_no)

This function stops any active transfer on the channel. If there is no active transfer on the channel,
this function returns SL_DMA_CHANNEL_IDLE

@pre Pre-conditions:

• sl_si91x_dma_init

sl_si91x_dma_allocate_channel

• sl_si91x_dma_simple_transfer/sl_si91x_dma_transfer

Returns

• DMA transfer status SL_STATUS_OK - Transfer stopped successfully SL_STATUS_IDLE - There is no active transfer on channel SL_STATUS_INVALID_PARAMETER - Invalid channel number SL_STATUS_NOT_INITIALIZED - DMA peripheral not initialized

sl_si91x_dma_channel_status_get#

sl_status_t sl_si91x_dma_channel_status_get (uint32_t dma_number, uint32_t channel_no)

This function returns the following channel status, SL_STATUS_DMA_CHANNEL_ALREADY_ALLOCATED - DMA channel allocated but no active transfer in progress SL_STATUS_BUSY - Channel is allocated and active transfer is in progress SL_STATUS_IDLE - Channel is not allocated.

• Pre-conditions:

  • sl_si91x_dma_init

Returns

• channel status SL_STATUS_IDLE - Channel is not allocated SL_STATUS_DMA_CHANNEL_ALREADY_ALLOCATED - Channel is already allocated and idle SL_STATUS_BUSY - Channel is allocated and busy SL_STATUS_NOT_INITIALIZED - DMA peripheral not initialized SL_STATUS_INVALID_PARAMETER - Channel no is invalid

sl_si91x_dma_channel_enable#

sl_status_t sl_si91x_dma_channel_enable (uint32_t dma_number, uint32_t channel_no)

This function enables the DMA channel.

Enabling channel will trigger DMA transfer if DMA is already enabled. Also, the channel should be allocated and transfer parameters should be configured before enabling the channel.

• Pre-conditions:

  • sl_si91x_dma_init

Returns

• channel status SL_STATUS_OK - Channel enable success SL_STATUS_NOT_INITIALIZED - DMA peripheral not initialized SL_STATUS_INVALID_PARAMETER - Channel no is invalid

sl_si91x_dma_channel_disable#

sl_status_t sl_si91x_dma_channel_disable (uint32_t dma_number, uint32_t channel_no)

This function disables the DMA channel.

Disabling the DMA channel will abort any ongoing active transfers on the channel. Enabling the channel back will not resume previous transfer.

• Pre-conditions:

  • sl_si91x_dma_init

Returns

• channel status SL_STATUS_OK - Channel disable success SL_STATUS_NOT_INITIALIZED - DMA peripheral not initialized SL_STATUS_INVALID_PARAMETER - Channel no is invalid

sl_si91x_dma_enable#

sl_status_t sl_si91x_dma_enable (uint32_t dma_number)

This function enables the DMA peripheral.

Enabling the DMA will trigger transfer if the channel is already enabled. Also, the channel should be allocated and transfer parameters should be configured before enabling the DMA.

• Pre-conditions:

  • sl_si91x_dma_init

Returns

• SL_STATUS_OK - Channel enable success SL_STATUS_NOT_INITIALIZED - DMA peripheral not initialized