Commit f533ec16 authored by Tomasz Moń's avatar Tomasz Moń Committed by Carles Cufi
Browse files

nrf_usbd_common: Remove dynamic feeders/consumers 



There is no point in setting the feeder or consumer at runtime. The time
saved due to not checking conditions on each transaction is smaller than
the additional cost of calling function via pointer.

Signed-off-by: default avatarTomasz Moń <tomasz.mon@nordicsemi.no>
parent 3e6b86ff

drivers/usb/common/nrf_usbd_common/nrf_usbd_common.c

+39 −301
Original line number Diff line number Diff line
@@ -233,10 +233,8 @@ static bool m_first_enable = true; 
 * buffer is ready.

 */

typedef struct {

	/** Handler for current transfer, function pointer. */

	nrf_usbd_common_handler_t handler;

	/** Context for transfer handler. */

	void *p_context;

	nrf_usbd_common_transfer_t transfer_state;

	bool more_transactions;

	/** Number of transferred bytes in the current transfer. */

	size_t transfer_cnt;

	/** Configured endpoint size. */
@@ -255,29 +253,7 @@ static struct { 
	usbd_ep_state_t ep_in[NRF_USBD_EPIN_CNT];   /*!< Status for IN endpoints. */

} m_ep_state;



/**

 * @brief Status variables for integrated feeders.

 *

 * Current status for integrated feeders (IN transfers).

 * Integrated feeders are used for default transfers:

 * 1. Simple RAM transfer.

 * 2. Simple flash transfer.

 * 3. RAM transfer with automatic ZLP.

 * 4. Flash transfer with automatic ZLP.

 */

nrf_usbd_common_transfer_t m_ep_feeder_state[NRF_USBD_EPIN_CNT];



/**

 * @brief Status variables for integrated consumers.

 *

 * Current status for integrated consumers.

 * Currently one type of transfer is supported:

 * 1. Transfer to RAM.

 *

 * Transfer is finished automatically when received data block is smaller

 * than the endpoint buffer or all the required data is received.

 */

nrf_usbd_common_transfer_t m_ep_consumer_state[NRF_USBD_EPOUT_CNT];

#define NRF_USBD_COMMON_FEEDER_BUFFER_SIZE NRF_USBD_COMMON_EPSIZE



/**

 * @brief Buffer used to send data directly from FLASH.
@@ -321,29 +297,10 @@ static inline nrf_usbd_event_t nrf_usbd_common_ep_to_endevent(nrf_usbd_common_ep 
	return (NRF_USBD_EPIN_CHECK(ep) ? epin_endev : epout_endev)[NRF_USBD_EP_NR_GET(ep)];

}



/**

 * @name Integrated feeders and consumers

 *

 * Internal, default functions for transfer processing.

 * @{

 */



/**

 * @brief Integrated consumer to RAM buffer.

 *

 * @param p_next    See @ref nrf_usbd_common_consumer_t documentation.

 * @param p_context See @ref nrf_usbd_common_consumer_t documentation.

 * @param ep_size   See @ref nrf_usbd_common_consumer_t documentation.

 * @param data_size See @ref nrf_usbd_common_consumer_t documentation.

 *

 * @retval true  Continue transfer.

 * @retval false This was the last transfer.

 */

bool nrf_usbd_common_consumer(nrf_usbd_common_ep_transfer_t *p_next, void *p_context,

static bool nrf_usbd_common_consumer(nrf_usbd_common_ep_transfer_t *p_next,

				     nrf_usbd_common_transfer_t *p_transfer,

				     size_t ep_size, size_t data_size)

{

	nrf_usbd_common_transfer_t *p_transfer = (nrf_usbd_common_transfer_t *)p_context;



	__ASSERT_NO_MSG(ep_size >= data_size);

	__ASSERT_NO_MSG((p_transfer->p_data.rx == NULL) || nrfx_is_in_ram(p_transfer->p_data.rx));
@@ -364,21 +321,10 @@ bool nrf_usbd_common_consumer(nrf_usbd_common_ep_transfer_t *p_next, void *p_con 
	return (ep_size == data_size) && (size != 0);

}



/**

 * @brief Integrated feeder from RAM source.

 *

 * @param[out]    p_next    See @ref nrf_usbd_common_feeder_t documentation.

 * @param[in,out] p_context See @ref nrf_usbd_common_feeder_t documentation.

 * @param[in]     ep_size   See @ref nrf_usbd_common_feeder_t documentation.

 *

 * @retval true  Continue transfer.

 * @retval false This was the last transfer.

 */

bool nrf_usbd_common_feeder_ram(nrf_usbd_common_ep_transfer_t *p_next,

				void *p_context, size_t ep_size)

static bool nrf_usbd_common_feeder(nrf_usbd_common_ep_transfer_t *p_next,

				   nrf_usbd_common_transfer_t *p_transfer,

				   size_t ep_size)

{

	nrf_usbd_common_transfer_t *p_transfer = (nrf_usbd_common_transfer_t *)p_context;



	__ASSERT_NO_MSG(nrfx_is_in_ram(p_transfer->p_data.tx));



	size_t tx_size = p_transfer->size;
@@ -387,125 +333,26 @@ bool nrf_usbd_common_feeder_ram(nrf_usbd_common_ep_transfer_t *p_next, 
		tx_size = ep_size;

	}



	if (!nrfx_is_in_ram(p_transfer->p_data.tx)) {

		__ASSERT_NO_MSG(tx_size <= NRF_USBD_COMMON_FEEDER_BUFFER_SIZE);

		memcpy(m_tx_buffer, (p_transfer->p_data.tx), tx_size);

		p_next->p_data.tx = m_tx_buffer;

	} else {

		p_next->p_data = p_transfer->p_data;

	p_next->size = tx_size;



	p_transfer->size -= tx_size;

	p_transfer->p_data.addr += tx_size;



	return (p_transfer->size != 0);

	}



/**

 * @brief Integrated feeder from RAM source with ZLP.

 *

 * @param[out]    p_next    See @ref nrf_usbd_common_feeder_t documentation.

 * @param[in,out] p_context See @ref nrf_usbd_common_feeder_t documentation.

 * @param[in]     ep_size   See @ref nrf_usbd_common_feeder_t documentation.

 *

 * @retval true  Continue transfer.

 * @retval false This was the last transfer.

 */

bool nrf_usbd_common_feeder_ram_zlp(nrf_usbd_common_ep_transfer_t *p_next,

				    void *p_context, size_t ep_size)

{

	nrf_usbd_common_transfer_t *p_transfer = (nrf_usbd_common_transfer_t *)p_context;



	__ASSERT_NO_MSG(nrfx_is_in_ram(p_transfer->p_data.tx));



	size_t tx_size = p_transfer->size;



	if (tx_size > ep_size) {

		tx_size = ep_size;

	}



	p_next->p_data.tx = (tx_size == 0) ? NULL : p_transfer->p_data.tx;

	p_next->size = tx_size;



	p_transfer->size -= tx_size;

	p_transfer->p_data.addr += tx_size;



	if (p_transfer->flags & NRF_USBD_COMMON_TRANSFER_ZLP_FLAG) {

		return (tx_size != 0);

}



/**

 * @brief Integrated feeder from a flash source.

 *

 * @param[out]    p_next    See @ref nrf_usbd_common_feeder_t documentation.

 * @param[in,out] p_context See @ref nrf_usbd_common_feeder_t documentation.

 * @param[in]     ep_size   See @ref nrf_usbd_common_feeder_t documentation.

 *

 * @retval true  Continue transfer.

 * @retval false This was the last transfer.

 */

bool nrf_usbd_common_feeder_flash(nrf_usbd_common_ep_transfer_t *p_next,

				  void *p_context, size_t ep_size)

{

	nrf_usbd_common_transfer_t *p_transfer = (nrf_usbd_common_transfer_t *)p_context;



	__ASSERT_NO_MSG(!nrfx_is_in_ram(p_transfer->p_data.tx));



	size_t tx_size = p_transfer->size;

	void *p_buffer = nrf_usbd_common_feeder_buffer_get();



	if (tx_size > ep_size) {

		tx_size = ep_size;

	}



	__ASSERT_NO_MSG(tx_size <= NRF_USBD_COMMON_FEEDER_BUFFER_SIZE);

	memcpy(p_buffer, (p_transfer->p_data.tx), tx_size);



	p_next->p_data.tx = p_buffer;

	p_next->size = tx_size;



	p_transfer->size -= tx_size;

	p_transfer->p_data.addr += tx_size;



	return (p_transfer->size != 0);

}



/**

 * @brief Integrated feeder from a flash source with ZLP.

 *

 * @param[out]    p_next    See @ref nrf_usbd_common_feeder_t documentation.

 * @param[in,out] p_context See @ref nrf_usbd_common_feeder_t documentation.

 * @param[in]     ep_size   See @ref nrf_usbd_common_feeder_t documentation.

 *

 * @retval true  Continue transfer.

 * @retval false This was the last transfer.

 */

bool nrf_usbd_common_feeder_flash_zlp(nrf_usbd_common_ep_transfer_t *p_next,

				      void *p_context, size_t ep_size)

{

	nrf_usbd_common_transfer_t *p_transfer = (nrf_usbd_common_transfer_t *)p_context;



	__ASSERT_NO_MSG(!nrfx_is_in_ram(p_transfer->p_data.tx));



	size_t tx_size = p_transfer->size;

	void *p_buffer = nrf_usbd_common_feeder_buffer_get();



	if (tx_size > ep_size) {

		tx_size = ep_size;

	}



	__ASSERT_NO_MSG(tx_size <= NRF_USBD_COMMON_FEEDER_BUFFER_SIZE);



	if (tx_size != 0) {

		memcpy(p_buffer, (p_transfer->p_data.tx), tx_size);

		p_next->p_data.tx = p_buffer;

	} else {

		p_next->p_data.tx = NULL;

		return (p_transfer->size != 0);

	}

	p_next->size = tx_size;



	p_transfer->size -= tx_size;

	p_transfer->p_data.addr += tx_size;



	return (tx_size != 0);

}



/** @} */



/**

 * @brief Change Driver endpoint number to HAL endpoint number.

 *
@@ -664,7 +511,7 @@ static inline void usbd_ep_abort(nrf_usbd_common_ep_t ep) 
			 */

			nrf_usbd_common_transfer_out_drop(ep);

		} else {

			p_state->handler.consumer = NULL;

			p_state->more_transactions = false;

			m_ep_dma_waiting &= ~(1U << ep2bit(ep));

			m_ep_ready &= ~(1U << ep2bit(ep));

		}
@@ -695,7 +542,7 @@ static inline void usbd_ep_abort(nrf_usbd_common_ep_t ep) 
			m_ep_dma_waiting &= ~(1U << ep2bit(ep));

			m_ep_ready |= 1U << ep2bit(ep);



			p_state->handler.feeder = NULL;

			p_state->more_transactions = false;

			p_state->status = NRF_USBD_COMMON_EP_ABORTED;

			NRF_USBD_COMMON_EP_TRANSFER_EVENT(evt, ep, NRF_USBD_COMMON_EP_ABORTED);

			m_event_handler(&evt);
@@ -780,7 +627,7 @@ static void nrf_usbd_dma_finished(nrf_usbd_common_ep_t ep) 
	if (p_state->status == NRF_USBD_COMMON_EP_ABORTED) {

		/* Clear transfer information just in case */

		m_ep_dma_waiting &= ~(1U << ep2bit(ep));

	} else if (!p_state->handler.consumer || !p_state->handler.feeder) {

	} else if (!p_state->more_transactions) {

		m_ep_dma_waiting &= ~(1U << ep2bit(ep));



		if (NRF_USBD_EPOUT_CHECK(ep) || (ep == NRF_USBD_COMMON_EPIN8)) {
@@ -991,26 +838,20 @@ static void usbd_dmareq_process(void) 
			nrf_usbd_common_ep_transfer_t transfer;

			bool continue_transfer;



			BUILD_ASSERT(offsetof(usbd_ep_state_t, handler.feeder) ==

				     offsetof(usbd_ep_state_t, handler.consumer),

				     "feeder and consumer must be in union");

			__ASSERT_NO_MSG((p_state->handler.feeder) != NULL);

			__ASSERT_NO_MSG(p_state->more_transactions);



			if (NRF_USBD_EPIN_CHECK(ep)) {

				/* Device -> Host */

				continue_transfer = p_state->handler.feeder(

					&transfer, p_state->p_context, p_state->max_packet_size);



				if (!continue_transfer) {

					p_state->handler.feeder = NULL;

				}

				continue_transfer = nrf_usbd_common_feeder(

					&transfer, &p_state->transfer_state,

					p_state->max_packet_size);

			} else {

				/* Host -> Device */

				const size_t rx_size = nrf_usbd_common_epout_size_get(ep);



				continue_transfer = p_state->handler.consumer(

					&transfer, p_state->p_context, p_state->max_packet_size,

					rx_size);

				continue_transfer = nrf_usbd_common_consumer(

					&transfer, &p_state->transfer_state,

					p_state->max_packet_size, rx_size);



				if (transfer.p_data.rx == NULL) {

					/* Dropping transfer - allow processing */
@@ -1033,10 +874,10 @@ static void usbd_dmareq_process(void) 
					 */

					__ASSERT_NO_MSG(transfer.size == rx_size);

				}

			}



			if (!continue_transfer) {

					p_state->handler.consumer = NULL;

				}

				p_state->more_transactions = false;

			}



			usbd_dma_pending_set();
@@ -1271,7 +1112,7 @@ nrfx_err_t nrf_usbd_common_init(nrf_usbd_common_event_handler_t event_handler) 
		usbd_ep_state_t *p_state = ep_state_access(ep);



		p_state->status = NRF_USBD_COMMON_EP_OK;

		p_state->handler.feeder = NULL;

		p_state->more_transactions = false;

		p_state->transfer_cnt = 0;

	}

	for (n = 0; n < NRF_USBD_EPOUT_CNT; ++n) {
@@ -1282,7 +1123,7 @@ nrfx_err_t nrf_usbd_common_init(nrf_usbd_common_event_handler_t event_handler) 
		usbd_ep_state_t *p_state = ep_state_access(ep);



		p_state->status = NRF_USBD_COMMON_EP_OK;

		p_state->handler.consumer = NULL;

		p_state->more_transactions = false;

		p_state->transfer_cnt = 0;

	}
@@ -1611,115 +1452,17 @@ nrfx_err_t nrf_usbd_common_ep_transfer(nrf_usbd_common_ep_t ep, 
		}

	} else {

		usbd_ep_state_t *p_state = ep_state_access(ep);

		/* Prepare transfer context and handler description */

		nrf_usbd_common_transfer_t *p_context;



		if (NRF_USBD_EPIN_CHECK(ep)) {

			p_context = m_ep_feeder_state + NRF_USBD_EP_NR_GET(ep);

			if (nrfx_is_in_ram(p_transfer->p_data.tx)) {

				/* RAM */

				if (0 == (p_transfer->flags & NRF_USBD_COMMON_TRANSFER_ZLP_FLAG)) {

					p_state->handler.feeder = nrf_usbd_common_feeder_ram;

					if (NRF_USBD_COMMON_ISO_DEBUG ||

					    (!NRF_USBD_EPISO_CHECK(ep))) {

						LOG_DBG("Transfer called on endpoint %x, "

							"size: %u, mode: "

							"RAM",

							ep, p_transfer->size);

					}

				} else {

					p_state->handler.feeder = nrf_usbd_common_feeder_ram_zlp;

					if (NRF_USBD_COMMON_ISO_DEBUG ||

					    (!NRF_USBD_EPISO_CHECK(ep))) {

						LOG_DBG("Transfer called on endpoint %x, "

							"size: %u, mode: "

							"RAM_ZLP",

							ep, p_transfer->size);

					}

				}

			} else {

				/* Flash */

				if (0 == (p_transfer->flags & NRF_USBD_COMMON_TRANSFER_ZLP_FLAG)) {

					p_state->handler.feeder = nrf_usbd_common_feeder_flash;

					if (NRF_USBD_COMMON_ISO_DEBUG ||

					    (!NRF_USBD_EPISO_CHECK(ep))) {

						LOG_DBG("Transfer called on endpoint %x, "

							"size: %u, mode: "

							"FLASH",

							ep, p_transfer->size);

					}

				} else {

					p_state->handler.feeder = nrf_usbd_common_feeder_flash_zlp;

					if (NRF_USBD_COMMON_ISO_DEBUG ||

					    (!NRF_USBD_EPISO_CHECK(ep))) {

						LOG_DBG("Transfer called on endpoint %x, "

							"size: %u, mode: "

							"FLASH_ZLP",

							ep, p_transfer->size);

					}

				}

			}

		} else {

			p_context = m_ep_consumer_state + NRF_USBD_EP_NR_GET(ep);

			__ASSERT_NO_MSG((p_transfer->p_data.rx == NULL) ||

		__ASSERT_NO_MSG(NRF_USBD_EPIN_CHECK(ep) ||

				(p_transfer->p_data.rx == NULL) ||

				(nrfx_is_in_ram(p_transfer->p_data.rx)));

			p_state->handler.consumer = nrf_usbd_common_consumer;

		}

		*p_context = *p_transfer;

		p_state->p_context = p_context;



		p_state->transfer_cnt = 0;

		p_state->status = NRF_USBD_COMMON_EP_OK;

		m_ep_dma_waiting |= 1U << ep_bitpos;

		ret = NRFX_SUCCESS;

		usbd_int_rise();

	}



	irq_unlock(irq_lock_key);



	return ret;

}



nrfx_err_t nrf_usbd_common_ep_handled_transfer(nrf_usbd_common_ep_t ep,

					 nrf_usbd_common_handler_desc_t const *p_handler)

{

	nrfx_err_t ret;

	const uint8_t ep_bitpos = ep2bit(ep);

	unsigned int irq_lock_key = irq_lock();



	__ASSERT_NO_MSG(p_handler != NULL);



	/* Setup data transaction can go only in one direction at a time */

	if ((NRF_USBD_EP_NR_GET(ep) == 0) && (ep != m_last_setup_dir)) {

		ret = NRFX_ERROR_INVALID_ADDR;

		if (NRF_USBD_COMMON_FAILED_TRANSFERS_DEBUG &&

		    (NRF_USBD_COMMON_ISO_DEBUG || (!NRF_USBD_EPISO_CHECK(ep)))) {

			LOG_DBG("Transfer failed: Invalid EP");

		}

	} else if ((m_ep_dma_waiting | ((~m_ep_ready) & NRF_USBD_COMMON_EPIN_BIT_MASK)) &

		   (1U << ep_bitpos)) {

		/* IN (Device -> Host) transfer has to be transmitted out to allow a new

		 * transmission

		 */

		ret = NRFX_ERROR_BUSY;

		if (NRF_USBD_COMMON_FAILED_TRANSFERS_DEBUG &&

		    (NRF_USBD_COMMON_ISO_DEBUG || (!NRF_USBD_EPISO_CHECK(ep)))) {

			LOG_DBG("Transfer failed: EP is busy");

		}

	} else {

		/* Transfer can be configured now */

		usbd_ep_state_t *p_state = ep_state_access(ep);

		p_state->more_transactions = true;

		p_state->transfer_state = *p_transfer;



		p_state->transfer_cnt = 0;

		p_state->handler = p_handler->handler;

		p_state->p_context = p_handler->p_context;

		p_state->status = NRF_USBD_COMMON_EP_OK;

		m_ep_dma_waiting |= 1U << ep_bitpos;



		ret = NRFX_SUCCESS;

		if (NRF_USBD_COMMON_ISO_DEBUG || (!NRF_USBD_EPISO_CHECK(ep))) {

			LOG_DBG("Transfer called on endpoint %x, mode: Handler", ep);

		}

		usbd_int_rise();

	}
@@ -1728,11 +1471,6 @@ nrfx_err_t nrf_usbd_common_ep_handled_transfer(nrf_usbd_common_ep_t ep, 
	return ret;

}



void *nrf_usbd_common_feeder_buffer_get(void)

{

	return m_tx_buffer;

}



nrf_usbd_common_ep_status_t nrf_usbd_common_ep_status_get(nrf_usbd_common_ep_t ep, size_t *p_size)

{

	nrf_usbd_common_ep_status_t ret;
@@ -1740,7 +1478,7 @@ nrf_usbd_common_ep_status_t nrf_usbd_common_ep_status_get(nrf_usbd_common_ep_t e 
	unsigned int irq_lock_key = irq_lock();



	*p_size = p_state->transfer_cnt;

	ret = (p_state->handler.consumer == NULL) ? p_state->status : NRF_USBD_COMMON_EP_BUSY;

	ret = (!p_state->more_transactions) ? p_state->status : NRF_USBD_COMMON_EP_BUSY;



	irq_unlock(irq_lock_key);

drivers/usb/common/nrf_usbd_common/nrf_usbd_common.h

+0 −118
Original line number Diff line number Diff line
@@ -41,13 +41,6 @@ extern "C" { 
 */

#define NRF_USBD_COMMON_ISOSIZE 1023



/**

 * @brief The size of internal feeder buffer.

 *

 * @sa nrf_usbd_common_feeder_buffer_get

 */

#define NRF_USBD_COMMON_FEEDER_BUFFER_SIZE NRF_USBD_COMMON_EPSIZE



/**

 * @name Macros for creating endpoint identifiers.

 *
@@ -266,82 +259,6 @@ typedef struct { 
	const nrf_usbd_common_transfer_t name = {                                     \

		.p_data = {.rx = (rx_buff)}, .size = (rx_size), .flags = 0}



/**

 * @brief USBD transfer feeder.

 *

 * Pointer for a transfer feeder.

 * Transfer feeder is a feedback function used to prepare a single

 * TX (Device->Host) endpoint transfer.

 *

 * The transfers provided by the feeder must be simple:

 * - The size of the transfer provided by this function is limited to a single endpoint buffer.

 *   Bigger transfers are not handled automatically in this case.

 * - Flash transfers are not automatically supported- you must copy them to the RAM buffer before.

 *

 * @note

 * This function may use @ref nrf_usbd_common_feeder_buffer_get to gain a temporary buffer

 * that can be used to prepare transfer.

 *

 * @param[out]    p_next    Structure with the data for the next transfer to be filled.

 *                          Required only if the function returns true.

 * @param[in,out] p_context Context variable configured with the transfer.

 * @param[in]     ep_size   The endpoint size.

 *

 * @retval false The current transfer is the last one - you do not need to call

 *               the function again.

 * @retval true  There is more data to be prepared and when the current transfer

 *               finishes, the feeder function is expected to be called again.

 */

typedef bool (*nrf_usbd_common_feeder_t)(nrf_usbd_common_ep_transfer_t *p_next, void *p_context,

				   size_t ep_size);



/**

 * @brief USBD transfer consumer.

 *

 * Pointer for a transfer consumer.

 * Transfer consumer is a feedback function used to prepare a single

 * RX (Host->Device) endpoint transfer.

 *

 * The transfer must provide a buffer big enough to fit the whole data from the endpoint.

 * Otherwise, the NRF_USBD_COMMON_EP_OVERLOAD event is generated.

 *

 * @param[out]    p_next    Structure with the data for the next transfer to be filled.

 *                          Required only if the function returns true.

 * @param[in,out] p_context Context variable configured with the transfer.

 * @param[in]     ep_size   The endpoint size.

 * @param[in]     data_size Number of received bytes in the endpoint buffer.

 *

 * @retval false Current transfer is the last one - you do not need to call

 *               the function again.

 * @retval true  There is more data to be prepared and when current transfer

 *               finishes, the feeder function is expected to be called again.

 */

typedef bool (*nrf_usbd_common_consumer_t)(nrf_usbd_common_ep_transfer_t *p_next, void *p_context,

				     size_t ep_size, size_t data_size);



/**

 * @brief Universal transfer handler.

 *

 * Union with feeder and consumer function pointer.

 */

typedef union {

	nrf_usbd_common_feeder_t feeder;     /*!< Feeder function pointer. */

	nrf_usbd_common_consumer_t consumer; /*!< Consumer function pointer. */

} nrf_usbd_common_handler_t;



/**

 * @brief USBD transfer descriptor.

 *

 * Universal structure that may hold the setup for callback configuration for

 * IN or OUT type of the transfer.

 */

typedef struct {

	/** Handler for the current transfer, function pointer. */

	nrf_usbd_common_handler_t handler;

	/** Context for the transfer handler. */

	void *p_context;

} nrf_usbd_common_handler_desc_t;



/**

 * @brief Setup packet structure.

 *
@@ -601,41 +518,6 @@ void nrf_usbd_common_ep_default_config(void); 
nrfx_err_t nrf_usbd_common_ep_transfer(nrf_usbd_common_ep_t ep,

				       nrf_usbd_common_transfer_t const *p_transfer);



/**

 * @brief Start sending data over the endpoint using the transfer handler function.

 *

 * This function initializes an endpoint transmission.

 * Just before data is transmitted, the transfer handler

 * is called and it prepares a data chunk.

 *

 * @param[in] ep        Endpoint number.

 *                      For an IN endpoint, sending is initiated.

 *                      For an OUT endpoint, receiving is initiated.

 * @param[in] p_handler Transfer handler - feeder for IN direction and consumer for

 *                      OUT direction.

 *

 * @retval NRFX_SUCCESS             Transfer queued or started.

 * @retval NRFX_ERROR_BUSY          Selected endpoint is pending.

 * @retval NRFX_ERROR_INVALID_ADDR  Unexpected transfer on EPIN0 or EPOUT0.

 */

nrfx_err_t nrf_usbd_common_ep_handled_transfer(nrf_usbd_common_ep_t ep,

					       nrf_usbd_common_handler_desc_t const *p_handler);



/**

 * @brief Get the temporary buffer to be used by the feeder.

 *

 * This buffer is used for TX transfers and it can be reused automatically

 * when the transfer is finished.

 * Use it for transfer preparation.

 *

 * May be used inside the feeder configured in @ref nrf_usbd_common_ep_handled_transfer.

 *

 * @return Pointer to the buffer that can be used temporarily.

 *

 * @sa NRF_USBD_COMMON_FEEDER_BUFFER_SIZE

 */

void *nrf_usbd_common_feeder_buffer_get(void);



/**

 * @brief Get the information about last finished or current transfer.

 *

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