klipper-dgus/lib/pru_rpmsg/include/pru_rpmsg.h

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/*
* Copyright (C) 2016 Texas Instruments Incorporated - http://www.ti.com/
*
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the
* distribution.
*
* * Neither the name of Texas Instruments Incorporated nor the names of
* its contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
/**
* File : pru_rpmsg.h
*
* Summary : An RPMsg interface for the PRU to use while communicating with
* the ARM host.
*
* Notes :
* - This file creates a structure (pru_rpmsg_transport) that contains
* pointers to two pru_virtqueue structures. This structure is used as the
* underlying transport layer of all RPMsg communication. Only one
* pru_rpmsg_transport structure is needed because multiple logical channels
* can use the same underlying transport.
* - This pru_rpmsg interface is meant to sit on top of the pru_virtqueue
* interface and abstract the communication even further away from the
* underlying data structures. The goal is to make the communication as
* simple as possible at the user application level.
* - The logic for the PRU side is summarized below:
*
* PRU Slave:
* - To receive buffer from the ARM host:
* pru_rpmsg_receive(*transport, *src, *dst, *data, *len);
* - To send buffer to the host:
* pru_rpmsg_send(*transport, src, dst, *data, len);
*/
#ifndef _PRU_RPMSG_H_
#define _PRU_RPMSG_H_
#include <pru_virtqueue.h>
#include <pru_virtio_ring.h>
/* Return value indicating no kick was sent */
#define PRU_RPMSG_NO_KICK 1
/* Return value indicating success */
#define PRU_RPMSG_SUCCESS 0
/* Return value indicating there were no available buffers */
#define PRU_RPMSG_NO_BUF_AVAILABLE -1
/* Return value indicating that the buffer from the virtqueue was too small */
#define PRU_RPMSG_BUF_TOO_SMALL -2
/* Return value indicating that an invalid head index was given */
#define PRU_RPMSG_INVALID_HEAD -3
/* Return value indication that an invalid event number was given */
#define PRU_RPMSG_INVALID_EVENT -4
/* Max PRU-ICSS system event number for pru_mst_intr */
#define MAX_VALID_EVENT 31
/* Min PRU-ICSS system event number for pru_mst_intr */
#define MIN_VALID_EVENT 16
/* The maximum size of the channel name and description */
#define RPMSG_NAME_SIZE 32
/* The maximum size of the buffer (including the header) */
#define RPMSG_BUF_SIZE 512
enum pru_rpmsg_ns_flags {
RPMSG_NS_CREATE = 0,
RPMSG_NS_DESTROY = 1
};
/**
* Summary : pru_rpmsg_transport is a structure that groups together the
* two pru_virtqueues that are needed for two-way communication
* with the ARM. This structure provides a logical wrapper for
* the transport layer of the application. NOTE: Multiple
* (logical) channels can be implemented on top of the same
* transport layer.
*
* Variables : virtqueue0: contains the pru_virtqueue that is used for the
* PRU->ARM communication
* virtqueue1: contains the pru_virtqueue that is used for
* the ARM->PRU communication
*/
struct pru_rpmsg_transport {
struct pru_virtqueue virtqueue0;
struct pru_virtqueue virtqueue1;
};
/**
* Summary : pru_rpmsg_init initializes the underlying transport layer
* data structures.
*
* Parameters : transport: a pointer to the transport data structure that
* contains the underlying data structures to be
* initialized
* vring0: a pointer to vring0 which is provided by the ARM
* core through the resource table
* vring1: a pointer to vring1 which is provided by the ARM
* core through the resource table
* to_arm_event: the number of the PRU-ICSS system event
* that is specified in the device tree that
* is used to 'kick' the ARM core
* from_arm_event: the number of the PRU-ICSS system event
* that is specified in the device tree
* that is used to receive 'kicks' from the
* ARM core
*
* Description : pru_rpmsg_init takes the vrings and the events provided
* through the resource table and initializes the transport
* layer. Once this function call is successful RPMsg
* channels can be created and used.
*
* Return Value : Returns PRU_RPMSG_INVALID_EVENT if the values provided
* in to_arm_event or from_arm_event are outside of the
* allowable range of events. Returns PRU_RPMSG_SUCCESS
* if the initialization is successful.
*/
int16_t pru_rpmsg_init(
struct pru_rpmsg_transport *transport,
struct fw_rsc_vdev_vring *vring0,
struct fw_rsc_vdev_vring *vring1,
uint32_t to_arm_event,
uint32_t from_arm_event
);
/**
* Summary : pru_rpmsg_receive receives a message, if available, from
* the ARM host.
*
* Parameters : transport: a pointer to the transport layer from which the
* message should be received
* src: a pointer that is populated with the source address
* where the message originated
* dst: a pointer that is populated with the destination
* address where the message was sent (can help determine
* for which channel the message is intended on the PRU)
* data: a pointer that is populated with a local data buffer
* containing the message payload
* len: a pointer that is populated with the length of the
* message payload
*
* Description : pru_rpmsg_receive uses the pru_virtqueue interface to get
* an available buffer, copy the buffer into local memory,
* add the buffer as a used buffer to the vring, and then kick
* the remote processor if necessary. The src, dst, data, and
* len pointers are populated with the information about the
* message and local buffer data if the reception is
* successful.
*
* Return Value : Returns PRU_RPMSG_NO_BUF_AVAILABLE if there is currently no
* buffer available for receive. Returns PRU_RPMSG_INVALID_HEAD
* if the head index returned for the available buffer is
* invalid. Returns PRU_RPMSG_SUCCESS if the message is
* successfully received.
*/
int16_t pru_rpmsg_receive(
struct pru_rpmsg_transport *transport,
uint16_t *src,
uint16_t *dst,
void *data,
uint16_t *len
);
/**
* Summary : pru_rpmsg_send sends a message to the ARM host using the
* virtqueues in the pru_rpmsg_transport structure. The
* source and destination address of the message are passed
* in as parameters to the function. The data to be sent and
* its length are passed in the data and len parameters.
*
* Parameters : transport: a pointer to the transport layer from which the
* message should be sent
* src: the source address where this message will originate
* dst: the destination address where the message will be sent
* data: a pointer to a local data buffer containing the
* message payload
* len: the length of the message payload
*
* Description : pru_rpmsg_send sends a message to the src parameter and
* from the dst parameter. The transport structure defines the
* underlying transport mechanism that will be used. The
* data parameter is a pointer to a local buffer that should
* be sent to the destination address and the len parameter is
* the length of that buffer.
*
* Return Value : Returns PRU_RPMSG_NO_BUF_AVAILABLE if there is currently no
* buffer available for send. Returns PRU_RPMSG_BUF_TOO_SMALL
* if the buffer from the vring is too small to hold the
* message payload being sent. Returns PRU_RPMSG_INVALID_HEAD
* if the head index returned for the send buffer is invalid.
* Returns PRU_RPMSG_SUCCESS if the message is successfully
* sent.
*/
int16_t pru_rpmsg_send(
struct pru_rpmsg_transport *transport,
uint32_t src,
uint32_t dst,
void *data,
uint16_t len
);
/**
* Summary : pru_rpmsg_channel uses an RPMsg Name Service Announcment
* to either create or destroy an RPMsg channel depending on
* the pru_rpmsg_ns_flags parameter that is specified.
*
* Parameters : flags: an enum that is used to create (RPMSG_NS_CREATE) or
* destroy (RPMSG_NS_DESTROY) an RPMsg channel
* transport: a pointer to the transport layer on which this
* Name Service Announcement will be sent
* name: the name of the channel being created or destroyed
* ******* The name of the channel is very important as
* ******* it is the method that Linux on the ARM uses
* ******* to connect a PRU firmware with a corresponding
* ******* Linux driver
* desc: the description of the RPMsg channel being created
* or destroyed
* port: the local source address of the RPMsg channel. This
* is the address where PRU messages destined for the
* ARM host will originate
*
* Description : pru_rpmsg_channel sends a message letting the ARM
* host know that a channel is to be created or destroyed. If
* a channel is to be created then this message will notify
* the name server on the ARM host to create a new channel. If
* a channel is to be destroyed this will tear down this
* logical channel of communication between the PRU and the
* ARM host.
*
* Return Value : Returns PRU_RPMSG_NO_BUF_AVAILABLE if there is currently no
* buffer available for send. Returns PRU_RPMSG_BUF_TOO_SMALL
* if the buffer from the vring is too small to hold the
* message payload being sent. Returns PRU_RPMSG_INVALID_HEAD
* if the head index returned for the send buffer is invalid.
* Returns PRU_RPMSG_SUCCESS if the message is successfully
* sent.
*/
int16_t pru_rpmsg_channel(
enum pru_rpmsg_ns_flags flags,
struct pru_rpmsg_transport *transport,
char *name,
char *desc,
int32_t port
);
#endif /* _PRU_RPMSG_H_ */