| /* 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 |