1*83d290c5STom Rini /* SPDX-License-Identifier: GPL-2.0 */ 249626ea8SStephen Warren /* 349626ea8SStephen Warren * Copyright (c) 2016, NVIDIA CORPORATION. 449626ea8SStephen Warren */ 549626ea8SStephen Warren 649626ea8SStephen Warren #ifndef _ASM_ARCH_TEGRA_IVC_H 749626ea8SStephen Warren #define _ASM_ARCH_TEGRA_IVC_H 849626ea8SStephen Warren 949626ea8SStephen Warren #include <common.h> 1049626ea8SStephen Warren 1149626ea8SStephen Warren /* 1249626ea8SStephen Warren * Tegra IVC is a communication protocol that transfers fixed-size frames 1349626ea8SStephen Warren * bi-directionally and in-order between the local CPU and some remote entity. 1449626ea8SStephen Warren * Communication is via a statically sized and allocated buffer in shared 1549626ea8SStephen Warren * memory and a notification mechanism. 1649626ea8SStephen Warren * 1749626ea8SStephen Warren * This API handles all aspects of the shared memory buffer's metadata, and 1849626ea8SStephen Warren * leaves all aspects of the frame content to the calling code; frames 1949626ea8SStephen Warren * typically contain some higher-level protocol. The notification mechanism is 2049626ea8SStephen Warren * also handled externally to this API, since it can vary from instance to 2149626ea8SStephen Warren * instance. 2249626ea8SStephen Warren * 2349626ea8SStephen Warren * The client model is to first find some free (for TX) or filled (for RX) 2449626ea8SStephen Warren * frame, process that frame's memory buffer (fill or read it), and then 2549626ea8SStephen Warren * inform the protocol that the frame has been filled/read, i.e. advance the 2649626ea8SStephen Warren * write/read pointer. If the channel is full, there may be no available frames 2749626ea8SStephen Warren * to fill/read. In this case, client code may either poll for an available 2849626ea8SStephen Warren * frame, or wait for the remote entity to send a notification to the local 2949626ea8SStephen Warren * CPU. 3049626ea8SStephen Warren */ 3149626ea8SStephen Warren 3249626ea8SStephen Warren /** 3349626ea8SStephen Warren * struct tegra_ivc - In-memory shared memory layout. 3449626ea8SStephen Warren * 3549626ea8SStephen Warren * This is described in detail in ivc.c. 3649626ea8SStephen Warren */ 3749626ea8SStephen Warren struct tegra_ivc_channel_header; 3849626ea8SStephen Warren 3949626ea8SStephen Warren /** 4049626ea8SStephen Warren * struct tegra_ivc - Software state of an IVC channel. 4149626ea8SStephen Warren * 4249626ea8SStephen Warren * This state is internal to the IVC code and should not be accessed directly 4349626ea8SStephen Warren * by clients. It is public solely so clients can allocate storage for the 4449626ea8SStephen Warren * structure. 4549626ea8SStephen Warren */ 4649626ea8SStephen Warren struct tegra_ivc { 4749626ea8SStephen Warren /** 4849626ea8SStephen Warren * rx_channel - Pointer to the shared memory region used to receive 4949626ea8SStephen Warren * messages from the remote entity. 5049626ea8SStephen Warren */ 5149626ea8SStephen Warren struct tegra_ivc_channel_header *rx_channel; 5249626ea8SStephen Warren /** 5349626ea8SStephen Warren * tx_channel - Pointer to the shared memory region used to send 5449626ea8SStephen Warren * messages to the remote entity. 5549626ea8SStephen Warren */ 5649626ea8SStephen Warren struct tegra_ivc_channel_header *tx_channel; 5749626ea8SStephen Warren /** 5849626ea8SStephen Warren * r_pos - The position in list of frames in rx_channel that we are 5949626ea8SStephen Warren * reading from. 6049626ea8SStephen Warren */ 6149626ea8SStephen Warren uint32_t r_pos; 6249626ea8SStephen Warren /** 6349626ea8SStephen Warren * w_pos - The position in list of frames in tx_channel that we are 6449626ea8SStephen Warren * writing to. 6549626ea8SStephen Warren */ 6649626ea8SStephen Warren uint32_t w_pos; 6749626ea8SStephen Warren /** 6849626ea8SStephen Warren * nframes - The number of frames allocated (in each direction) in 6949626ea8SStephen Warren * shared memory. 7049626ea8SStephen Warren */ 7149626ea8SStephen Warren uint32_t nframes; 7249626ea8SStephen Warren /** 7349626ea8SStephen Warren * frame_size - The size of each frame in shared memory. 7449626ea8SStephen Warren */ 7549626ea8SStephen Warren uint32_t frame_size; 7649626ea8SStephen Warren /** 7749626ea8SStephen Warren * notify - Function to call to notify the remote processor of a 7849626ea8SStephen Warren * change in channel state. 7949626ea8SStephen Warren */ 8049626ea8SStephen Warren void (*notify)(struct tegra_ivc *); 8149626ea8SStephen Warren }; 8249626ea8SStephen Warren 8349626ea8SStephen Warren /** 8449626ea8SStephen Warren * tegra_ivc_read_get_next_frame - Locate the next frame to receive. 8549626ea8SStephen Warren * 8649626ea8SStephen Warren * Locate the next frame to be received/processed, return the address of the 8749626ea8SStephen Warren * frame, and do not remove it from the queue. Repeated calls to this function 8849626ea8SStephen Warren * will return the same address until tegra_ivc_read_advance() is called. 8949626ea8SStephen Warren * 9049626ea8SStephen Warren * @ivc The IVC channel. 9149626ea8SStephen Warren * @frame Pointer to be filled with the address of the frame to receive. 9249626ea8SStephen Warren * 9349626ea8SStephen Warren * @return 0 if a frame is available, else a negative error code. 9449626ea8SStephen Warren */ 9549626ea8SStephen Warren int tegra_ivc_read_get_next_frame(struct tegra_ivc *ivc, void **frame); 9649626ea8SStephen Warren 9749626ea8SStephen Warren /** 9849626ea8SStephen Warren * tegra_ivc_read_advance - Advance the read queue. 9949626ea8SStephen Warren * 10049626ea8SStephen Warren * Inform the protocol and remote entity that the frame returned by 10149626ea8SStephen Warren * tegra_ivc_read_get_next_frame() has been processed. The remote end may then 10249626ea8SStephen Warren * re-use it to transmit further data. Subsequent to this function returning, 10349626ea8SStephen Warren * tegra_ivc_read_get_next_frame() will return a different frame. 10449626ea8SStephen Warren * 10549626ea8SStephen Warren * @ivc The IVC channel. 10649626ea8SStephen Warren * 10749626ea8SStephen Warren * @return 0 if OK, else a negative error code. 10849626ea8SStephen Warren */ 10949626ea8SStephen Warren int tegra_ivc_read_advance(struct tegra_ivc *ivc); 11049626ea8SStephen Warren 11149626ea8SStephen Warren /** 11249626ea8SStephen Warren * tegra_ivc_write_get_next_frame - Locate the next frame to fill for transmit. 11349626ea8SStephen Warren * 11449626ea8SStephen Warren * Locate the next frame to be filled for transmit, return the address of the 11549626ea8SStephen Warren * frame, and do not add it to the queue. Repeated calls to this function 11649626ea8SStephen Warren * will return the same address until tegra_ivc_read_advance() is called. 11749626ea8SStephen Warren * 11849626ea8SStephen Warren * @ivc The IVC channel. 11949626ea8SStephen Warren * @frame Pointer to be filled with the address of the frame to fill. 12049626ea8SStephen Warren * 12149626ea8SStephen Warren * @return 0 if a frame is available, else a negative error code. 12249626ea8SStephen Warren */ 12349626ea8SStephen Warren int tegra_ivc_write_get_next_frame(struct tegra_ivc *ivc, void **frame); 12449626ea8SStephen Warren 12549626ea8SStephen Warren /** 12649626ea8SStephen Warren * tegra_ivc_write_advance - Advance the write queue. 12749626ea8SStephen Warren * 12849626ea8SStephen Warren * Inform the protocol and remote entity that the frame returned by 12949626ea8SStephen Warren * tegra_ivc_write_get_next_frame() has been filled and should be transmitted. 13049626ea8SStephen Warren * The remote end may then read data from it. Subsequent to this function 13149626ea8SStephen Warren * returning, tegra_ivc_write_get_next_frame() will return a different frame. 13249626ea8SStephen Warren * 13349626ea8SStephen Warren * @ivc The IVC channel. 13449626ea8SStephen Warren * 13549626ea8SStephen Warren * @return 0 if OK, else a negative error code. 13649626ea8SStephen Warren */ 13749626ea8SStephen Warren int tegra_ivc_write_advance(struct tegra_ivc *ivc); 13849626ea8SStephen Warren 13949626ea8SStephen Warren /** 14049626ea8SStephen Warren * tegra_ivc_channel_notified - handle internal messages 14149626ea8SStephen Warren * 14249626ea8SStephen Warren * This function must be called following every notification. 14349626ea8SStephen Warren * 14449626ea8SStephen Warren * @ivc The IVC channel. 14549626ea8SStephen Warren * 14649626ea8SStephen Warren * @return 0 if the channel is ready for communication, or -EAGAIN if a 14749626ea8SStephen Warren * channel reset is in progress. 14849626ea8SStephen Warren */ 14949626ea8SStephen Warren int tegra_ivc_channel_notified(struct tegra_ivc *ivc); 15049626ea8SStephen Warren 15149626ea8SStephen Warren /** 15249626ea8SStephen Warren * tegra_ivc_channel_reset - initiates a reset of the shared memory state 15349626ea8SStephen Warren * 15449626ea8SStephen Warren * This function must be called after a channel is initialized but before it 15549626ea8SStephen Warren * is used for communication. The channel will be ready for use when a 15649626ea8SStephen Warren * subsequent call to notify the remote of the channel reset indicates the 15749626ea8SStephen Warren * reset operation is complete. 15849626ea8SStephen Warren * 15949626ea8SStephen Warren * @ivc The IVC channel. 16049626ea8SStephen Warren */ 16149626ea8SStephen Warren void tegra_ivc_channel_reset(struct tegra_ivc *ivc); 16249626ea8SStephen Warren 16349626ea8SStephen Warren /** 16449626ea8SStephen Warren * tegra_ivc_init - Initialize a channel's software state. 16549626ea8SStephen Warren * 16649626ea8SStephen Warren * @ivc The IVC channel. 16749626ea8SStephen Warren * @rx_base Address of the the RX shared memory buffer. 16849626ea8SStephen Warren * @tx_base Address of the the TX shared memory buffer. 16949626ea8SStephen Warren * @nframes Number of frames in each shared memory buffer. 17049626ea8SStephen Warren * @frame_size Size of each frame. 17149626ea8SStephen Warren * 17249626ea8SStephen Warren * @return 0 if OK, else a negative error code. 17349626ea8SStephen Warren */ 17449626ea8SStephen Warren int tegra_ivc_init(struct tegra_ivc *ivc, ulong rx_base, ulong tx_base, 17549626ea8SStephen Warren uint32_t nframes, uint32_t frame_size, 17649626ea8SStephen Warren void (*notify)(struct tegra_ivc *)); 17749626ea8SStephen Warren 17849626ea8SStephen Warren #endif 179