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/*
* Copyright (c) 2021 Nordic Semiconductor ASA
*
* SPDX-License-Identifier: Apache-2.0
*/
#ifndef ZEPHYR_INCLUDE_IPC_IPC_SERVICE_H_
#define ZEPHYR_INCLUDE_IPC_IPC_SERVICE_H_
#include <stdio.h>
#include <device.h>
#ifdef __cplusplus
extern "C" {
#endif
/**
* @brief IPC Service API
* @defgroup ipc_service_api IPC service APIs
* @{
*
* Some terminology:
*
* - INSTANCE: an instance is the external representation of a physical
* communication channel between two domains / CPUs.
*
* The actual implementation and internal representation of the
* instance is peculiar to each backend. For example for
* OpenAMP-based backends, an instance is usually represented by a
* shared memory region and a couple of IPM devices for RX/TX
* signalling.
*
* It's important to note that an instance per se is not used to
* send data between domains / CPUs. To send and receive data the
* user have to create (register) an endpoint in the instance
* connecting the two domains of interest.
*
* It's possible to have zero or multiple endpoints in one single
* instance, each one used to exchange data, possibly with different
* priorities.
*
* The creation of the instances is left to the backend (usually at
* init time), while the registration of the endpoints is left to
* the user (usually at run time).
*
* - ENDPOINT: an endpoint is the entity the user must use to send / receive
* data between two domains (connected by the instance). An
* endpoint is always associated to an instance.
*
* - BACKEND: the backend must take care of at least two different things:
*
* 1) creating the instances at init time
* 2) creating / registering the endpoints onto an instance at run
* time when requested by the user
*
* The API doesn't mandate a way for the backend to create the
* instances but itis strongly recommended to use the DT to retrieve
* the configuration parameters for the instance.
*
* Common API usage from the application prospective:
*
* HOST REMOTE
* -----------------------------------------------------------------------------
* # Open the (same) instance on host and remote
* ipc_service_open() ipc_service_open()
*
* # Register the endpoints
* ipc_service_register_endpoint() ipc_service_register_endpoint()
* .bound() .bound()
*
* # After the .bound() callbacks are received the communication channel
* # is ready to be used
*
* # Start sending and receiving data
* ipc_service_send()
* .receive()
* ipc_service_send()
* .receive()
*
*
* Common API usage from the application prospective when using NOCOPY feature:
*
* HOST REMOTE
* -----------------------------------------------------------------------------
* ipc_service_open() ipc_service_open()
*
* ipc_service_register_endpoint() ipc_service_register_endpoint()
* .bound() .bound()
*
* # Get a pointer to an available TX buffer
* ipc_service_get_tx_buffer()
*
* # Fill the buffer with data
*
* # Send out the buffer
* ipc_service_send_nocopy()
* .receive()
*
* # Get hold of the received RX buffer
* # in the .receive callback
* ipc_service_hold_rx_buffer()
*
* # Copy the data out of the buffer at
* # user convenience
*
* # Release the buffer when done
* ipc_service_release_rx_buffer()
*
* # Get another TX buffer
* ipc_service_get_tx_buffer()
*
* # We can also drop it if needed
* ipc_service_drop_tx_buffer()
*
*/
/** @brief Event callback structure.
*
* It is registered during endpoint registration.
* This structure is part of the endpoint configuration.
*/
struct ipc_service_cb {
/** @brief Bind was successful.
*
* This callback is called when the endpoint binding is successful.
*
* @param[in] priv Private user data.
*/
void (*bound)(void *priv);
/** @brief New packet arrived.
*
* This callback is called when new data is received.
*
* @note When @ref ipc_service_hold_rx_buffer is not used, the data
* buffer is to be considered released and available again only
* when this callback returns.
*
* @param[in] data Pointer to data buffer.
* @param[in] len Length of @a data.
* @param[in] priv Private user data.
*/
void (*received)(const void *data, size_t len, void *priv);
/** @brief An error occurred.
*
* @param[in] message Error message.
* @param[in] priv Private user data.
*/
void (*error)(const char *message, void *priv);
};
/** @brief Endpoint instance.
*
* Token is not important for user of the API. It is implemented in a
* specific backend.
*/
struct ipc_ept {
/** Instance this endpoint belongs to. */
const struct device *instance;
/** Backend-specific token used to identify an endpoint in an instance. */
void *token;
};
/** @brief Endpoint configuration structure. */
struct ipc_ept_cfg {
/** Name of the endpoint. */
const char *name;
/** Endpoint priority. If the backend supports priorities. */
int prio;
/** Event callback structure. */
struct ipc_service_cb cb;
/** Private user data. */
void *priv;
};
/** @brief Open an instance
*
* Function to be used to open an instance before being able to register a new
* endpoint on it.
*
* @param[in] instance Instance to open.
*
* @retval -EINVAL when instance configuration is invalid.
* @retval -EIO when no backend is registered.
* @retval -EALREADY when the instance is already opened (or being opened).
*
* @retval 0 on success or when not implemented on the backend (not needed).
* @retval other errno codes depending on the implementation of the backend.
*/
int ipc_service_open_instance(const struct device *instance);
/** @brief Register IPC endpoint onto an instance.
*
* Registers IPC endpoint onto an instance to enable communication with a
* remote device.
*
* The same function registers endpoints for both host and remote devices.
*
* @param[in] instance Instance to register the endpoint onto.
* @param[in] ept Endpoint object.
* @param[in] cfg Endpoint configuration.
*
* @note Keep the variable pointed by @p cfg alive when endpoint is in use.
*
* @retval -EIO when no backend is registered.
* @retval -EINVAL when instance, endpoint or configuration is invalid.
* @retval -EBUSY when the instance is busy.
*
* @retval 0 on success.
* @retval other errno codes depending on the implementation of the backend.
*/
int ipc_service_register_endpoint(const struct device *instance,
struct ipc_ept *ept,
const struct ipc_ept_cfg *cfg);
/** @brief Send data using given IPC endpoint.
*
* @param[in] ept Registered endpoint by @ref ipc_service_register_endpoint.
* @param[in] data Pointer to the buffer to send.
* @param[in] len Number of bytes to send.
*
* @retval -EIO when no backend is registered or send hook is missing from
* backend.
* @retval -EINVAL when instance or endpoint is invalid.
* @retval -EBADMSG when the data is invalid (i.e. invalid data format,
* invalid length, ...)
* @retval -EBUSY when the instance is busy.
*
* @retval bytes number of bytes sent.
* @retval other errno codes depending on the implementation of the backend.
*/
int ipc_service_send(struct ipc_ept *ept, const void *data, size_t len);
/** @brief Get the TX buffer size
*
* Get the maximal size of a buffer which can be obtained by @ref
* ipc_service_get_tx_buffer
*
* @param[in] ept Registered endpoint by @ref ipc_service_register_endpoint.
*
* @retval -EIO when no backend is registered or send hook is missing from
* backend.
* @retval -EINVAL when instance or endpoint is invalid.
* @retval -ENOTSUP when the operation is not supported by backend.
*
* @retval size TX buffer size on success.
* @retval other errno codes depending on the implementation of the backend.
*/
int ipc_service_get_tx_buffer_size(struct ipc_ept *ept);
/** @brief Get an empty TX buffer to be sent using @ref ipc_service_send_nocopy
*
* This function can be called to get an empty TX buffer so that the
* application can directly put its data into the sending buffer without copy
* from an application buffer.
*
* It is the application responsibility to correctly fill the allocated TX
* buffer with data and passing correct parameters to @ref
* ipc_service_send_nocopy function to perform data no-copy-send mechanism.
*
* The size parameter can be used to request a buffer with a certain size:
* - if the size can be accommodated the function returns no errors and the
* buffer is allocated
* - if the requested size is too big, the function returns -ENOMEM and the
* the buffer is not allocated.
* - if the requested size is '0' the buffer is allocated with the maximum
* allowed size.
*
* In all the cases on return the size parameter contains the maximum size for
* the returned buffer.
*
* When the function returns no errors, the buffer is intended as allocated
* and it is released under two conditions: (1) when sending the buffer using
* @ref ipc_service_send_nocopy (and in this case the buffer is automatically
* released by the backend), (2) when using @ref ipc_service_drop_tx_buffer on
* a buffer not sent.
*
* @param[in] ept Registered endpoint by @ref ipc_service_register_endpoint.
* @param[out] data Pointer to the empty TX buffer.
* @param[in,out] size Pointer to store the requested TX buffer size. If the
* function returns -ENOMEM, this parameter returns the
* maximum allowed size.
* @param[in] wait Timeout waiting for an available TX buffer.
*
* @retval -EIO when no backend is registered or send hook is missing from
* backend.
* @retval -EINVAL when instance or endpoint is invalid.
* @retval -ENOTSUP when the operation or the timeout is not supported by backend.
* @retval -ENOBUFS when there are no TX buffers available.
* @retval -EALREADY when a buffer was already claimed and not yet released.
* @retval -ENOMEM when the requested size is too big (and the size parameter
* contains the maximum allowed size).
*
* @retval 0 on success.
* @retval other errno codes depending on the implementation of the backend.
*/
int ipc_service_get_tx_buffer(struct ipc_ept *ept, void **data, uint32_t *size, k_timeout_t wait);
/** @brief Drop and release a TX buffer
*
* Drop and release a TX buffer. It is possible to drop only TX buffers
* obtained by using @ref ipc_service_get_tx_buffer.
*
* @param[in] ept Registered endpoint by @ref ipc_service_register_endpoint.
* @param[in] data Pointer to the TX buffer.
*
* @retval -EIO when no backend is registered or send hook is missing from
* backend.
* @retval -EINVAL when instance or endpoint is invalid.
* @retval -ENOTSUP when this is not supported by backend.
* @retval -EALREADY when the buffer was already dropped.
* @retval -ENXIO when the buffer was not obtained using @ref
* ipc_service_get_tx_buffer
*
* @retval 0 on success.
* @retval other errno codes depending on the implementation of the backend.
*/
int ipc_service_drop_tx_buffer(struct ipc_ept *ept, const void *data);
/** @brief Send data in a TX buffer reserved by @ref ipc_service_get_tx_buffer
* using the given IPC endpoint.
*
* This is equivalent to @ref ipc_service_send but in this case the TX buffer
* has been obtained by using @ref ipc_service_get_tx_buffer.
*
* The application has to take the responsibility for getting the TX buffer
* using @ref ipc_service_get_tx_buffer and filling the TX buffer with the data.
*
* After the @ref ipc_service_send_nocopy function is issued the TX buffer is
* no more owned by the sending task and must not be touched anymore unless
* the function fails and returns an error.
*
* If this function returns an error, @ref ipc_service_drop_tx_buffer can be
* used to drop the TX buffer.
*
* @param[in] ept Registered endpoint by @ref ipc_service_register_endpoint.
* @param[in] data Pointer to the buffer to send obtained by @ref
* ipc_service_get_tx_buffer.
* @param[in] len Number of bytes to send.
*
* @retval -EIO when no backend is registered or send hook is missing from
* backend.
* @retval -EINVAL when instance or endpoint is invalid.
* @retval -EBADMSG when the data is invalid (i.e. invalid data format,
* invalid length, ...)
* @retval -EBUSY when the instance is busy.
*
* @retval bytes number of bytes sent.
* @retval other errno codes depending on the implementation of the backend.
*/
int ipc_service_send_nocopy(struct ipc_ept *ept, const void *data, size_t len);
/** @brief Holds the RX buffer for usage outside the receive callback.
*
* Calling this function prevents the receive buffer from being released
* back to the pool of shmem buffers. This function can be called in the
* receive callback when the user does not want to copy the message out in
* the callback itself.
*
* After the message is processed, the application must release the buffer
* using the @ref ipc_service_release_rx_buffer function.
*
* @param[in] ept Registered endpoint by @ref ipc_service_register_endpoint.
* @param[in] data Pointer to the RX buffer to release.
*
* @retval -EIO when no backend is registered or release hook is missing from
* backend.
* @retval -EINVAL when instance or endpoint is invalid.
* @retval -EALREADY when the buffer data has been hold already.
* @retval -ENOTSUP when this is not supported by backend.
*
* @retval 0 on success.
* @retval other errno codes depending on the implementation of the backend.
*/
int ipc_service_hold_rx_buffer(struct ipc_ept *ept, void *data);
/** @brief Release the RX buffer for future reuse.
*
* When supported by the backend, this function can be called after the
* received message has been processed and the buffer can be marked as
* reusable again.
*
* It is possible to release only RX buffers on which @ref
* ipc_service_hold_rx_buffer was previously used.
*
* @param[in] ept Registered endpoint by @ref ipc_service_register_endpoint.
* @param[in] data Pointer to the RX buffer to release.
*
* @retval -EIO when no backend is registered or release hook is missing from
* backend.
* @retval -EINVAL when instance or endpoint is invalid.
* @retval -EALREADY when the buffer data has been already released.
* @retval -ENOTSUP when this is not supported by backend.
* @retval -ENXIO when the buffer was not hold before using @ref
* ipc_service_hold_rx_buffer
*
* @retval 0 on success.
* @retval other errno codes depending on the implementation of the backend.
*/
int ipc_service_release_rx_buffer(struct ipc_ept *ept, void *data);
/**
* @}
*/
#ifdef __cplusplus
}
#endif
#endif /* ZEPHYR_INCLUDE_IPC_IPC_SERVICE_H_ */