mirror of
https://github.com/AsahiLinux/u-boot
synced 2024-12-05 02:51:00 +00:00
185f812c41
Sphinx expects Return: and not @return to indicate a return value. find . -name '*.c' -exec \ sed -i 's/^\(\s\)\*\(\s*\)@return\(\s\)/\1*\2Return:\3/' {} \; find . -name '*.h' -exec \ sed -i 's/^\(\s\)\*\(\s*\)@return\(\s\)/\1*\2Return:\3/' {} \; Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
176 lines
5.7 KiB
C
176 lines
5.7 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
|
|
/*
|
|
* Copyright (c) 2016, NVIDIA CORPORATION.
|
|
*/
|
|
|
|
#ifndef _ASM_ARCH_TEGRA_IVC_H
|
|
#define _ASM_ARCH_TEGRA_IVC_H
|
|
|
|
/*
|
|
* Tegra IVC is a communication protocol that transfers fixed-size frames
|
|
* bi-directionally and in-order between the local CPU and some remote entity.
|
|
* Communication is via a statically sized and allocated buffer in shared
|
|
* memory and a notification mechanism.
|
|
*
|
|
* This API handles all aspects of the shared memory buffer's metadata, and
|
|
* leaves all aspects of the frame content to the calling code; frames
|
|
* typically contain some higher-level protocol. The notification mechanism is
|
|
* also handled externally to this API, since it can vary from instance to
|
|
* instance.
|
|
*
|
|
* The client model is to first find some free (for TX) or filled (for RX)
|
|
* frame, process that frame's memory buffer (fill or read it), and then
|
|
* inform the protocol that the frame has been filled/read, i.e. advance the
|
|
* write/read pointer. If the channel is full, there may be no available frames
|
|
* to fill/read. In this case, client code may either poll for an available
|
|
* frame, or wait for the remote entity to send a notification to the local
|
|
* CPU.
|
|
*/
|
|
|
|
/**
|
|
* struct tegra_ivc - In-memory shared memory layout.
|
|
*
|
|
* This is described in detail in ivc.c.
|
|
*/
|
|
struct tegra_ivc_channel_header;
|
|
|
|
/**
|
|
* struct tegra_ivc - Software state of an IVC channel.
|
|
*
|
|
* This state is internal to the IVC code and should not be accessed directly
|
|
* by clients. It is public solely so clients can allocate storage for the
|
|
* structure.
|
|
*/
|
|
struct tegra_ivc {
|
|
/**
|
|
* rx_channel - Pointer to the shared memory region used to receive
|
|
* messages from the remote entity.
|
|
*/
|
|
struct tegra_ivc_channel_header *rx_channel;
|
|
/**
|
|
* tx_channel - Pointer to the shared memory region used to send
|
|
* messages to the remote entity.
|
|
*/
|
|
struct tegra_ivc_channel_header *tx_channel;
|
|
/**
|
|
* r_pos - The position in list of frames in rx_channel that we are
|
|
* reading from.
|
|
*/
|
|
uint32_t r_pos;
|
|
/**
|
|
* w_pos - The position in list of frames in tx_channel that we are
|
|
* writing to.
|
|
*/
|
|
uint32_t w_pos;
|
|
/**
|
|
* nframes - The number of frames allocated (in each direction) in
|
|
* shared memory.
|
|
*/
|
|
uint32_t nframes;
|
|
/**
|
|
* frame_size - The size of each frame in shared memory.
|
|
*/
|
|
uint32_t frame_size;
|
|
/**
|
|
* notify - Function to call to notify the remote processor of a
|
|
* change in channel state.
|
|
*/
|
|
void (*notify)(struct tegra_ivc *);
|
|
};
|
|
|
|
/**
|
|
* tegra_ivc_read_get_next_frame - Locate the next frame to receive.
|
|
*
|
|
* Locate the next frame to be received/processed, return the address of the
|
|
* frame, and do not remove it from the queue. Repeated calls to this function
|
|
* will return the same address until tegra_ivc_read_advance() is called.
|
|
*
|
|
* @ivc The IVC channel.
|
|
* @frame Pointer to be filled with the address of the frame to receive.
|
|
*
|
|
* Return: 0 if a frame is available, else a negative error code.
|
|
*/
|
|
int tegra_ivc_read_get_next_frame(struct tegra_ivc *ivc, void **frame);
|
|
|
|
/**
|
|
* tegra_ivc_read_advance - Advance the read queue.
|
|
*
|
|
* Inform the protocol and remote entity that the frame returned by
|
|
* tegra_ivc_read_get_next_frame() has been processed. The remote end may then
|
|
* re-use it to transmit further data. Subsequent to this function returning,
|
|
* tegra_ivc_read_get_next_frame() will return a different frame.
|
|
*
|
|
* @ivc The IVC channel.
|
|
*
|
|
* Return: 0 if OK, else a negative error code.
|
|
*/
|
|
int tegra_ivc_read_advance(struct tegra_ivc *ivc);
|
|
|
|
/**
|
|
* tegra_ivc_write_get_next_frame - Locate the next frame to fill for transmit.
|
|
*
|
|
* Locate the next frame to be filled for transmit, return the address of the
|
|
* frame, and do not add it to the queue. Repeated calls to this function
|
|
* will return the same address until tegra_ivc_read_advance() is called.
|
|
*
|
|
* @ivc The IVC channel.
|
|
* @frame Pointer to be filled with the address of the frame to fill.
|
|
*
|
|
* Return: 0 if a frame is available, else a negative error code.
|
|
*/
|
|
int tegra_ivc_write_get_next_frame(struct tegra_ivc *ivc, void **frame);
|
|
|
|
/**
|
|
* tegra_ivc_write_advance - Advance the write queue.
|
|
*
|
|
* Inform the protocol and remote entity that the frame returned by
|
|
* tegra_ivc_write_get_next_frame() has been filled and should be transmitted.
|
|
* The remote end may then read data from it. Subsequent to this function
|
|
* returning, tegra_ivc_write_get_next_frame() will return a different frame.
|
|
*
|
|
* @ivc The IVC channel.
|
|
*
|
|
* Return: 0 if OK, else a negative error code.
|
|
*/
|
|
int tegra_ivc_write_advance(struct tegra_ivc *ivc);
|
|
|
|
/**
|
|
* tegra_ivc_channel_notified - handle internal messages
|
|
*
|
|
* This function must be called following every notification.
|
|
*
|
|
* @ivc The IVC channel.
|
|
*
|
|
* Return: 0 if the channel is ready for communication, or -EAGAIN if a
|
|
* channel reset is in progress.
|
|
*/
|
|
int tegra_ivc_channel_notified(struct tegra_ivc *ivc);
|
|
|
|
/**
|
|
* tegra_ivc_channel_reset - initiates a reset of the shared memory state
|
|
*
|
|
* This function must be called after a channel is initialized but before it
|
|
* is used for communication. The channel will be ready for use when a
|
|
* subsequent call to notify the remote of the channel reset indicates the
|
|
* reset operation is complete.
|
|
*
|
|
* @ivc The IVC channel.
|
|
*/
|
|
void tegra_ivc_channel_reset(struct tegra_ivc *ivc);
|
|
|
|
/**
|
|
* tegra_ivc_init - Initialize a channel's software state.
|
|
*
|
|
* @ivc The IVC channel.
|
|
* @rx_base Address of the the RX shared memory buffer.
|
|
* @tx_base Address of the the TX shared memory buffer.
|
|
* @nframes Number of frames in each shared memory buffer.
|
|
* @frame_size Size of each frame.
|
|
*
|
|
* Return: 0 if OK, else a negative error code.
|
|
*/
|
|
int tegra_ivc_init(struct tegra_ivc *ivc, ulong rx_base, ulong tx_base,
|
|
uint32_t nframes, uint32_t frame_size,
|
|
void (*notify)(struct tegra_ivc *));
|
|
|
|
#endif
|