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Diffstat (limited to 'arch/arm/include/asm')
-rw-r--r-- | arch/arm/include/asm/arch-tegra/ivc.h | 179 |
1 files changed, 179 insertions, 0 deletions
diff --git a/arch/arm/include/asm/arch-tegra/ivc.h b/arch/arm/include/asm/arch-tegra/ivc.h new file mode 100644 index 0000000..7f2287a --- /dev/null +++ b/arch/arm/include/asm/arch-tegra/ivc.h @@ -0,0 +1,179 @@ +/* + * Copyright (c) 2016, NVIDIA CORPORATION. + * + * SPDX-License-Identifier: GPL-2.0 + */ + +#ifndef _ASM_ARCH_TEGRA_IVC_H +#define _ASM_ARCH_TEGRA_IVC_H + +#include <common.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 |