1 /* SPDX-License-Identifier: GPL-2.0-only */
2 /*
3  * Copyright (c) 2016, NVIDIA CORPORATION.  All rights reserved.
4  */
5 
6 #ifndef __TEGRA_IVC_H
7 
8 #include <linux/device.h>
9 #include <linux/dma-mapping.h>
10 #include <linux/types.h>
11 
12 struct tegra_ivc_header;
13 
14 struct tegra_ivc {
15 	struct device *peer;
16 
17 	struct {
18 		struct tegra_ivc_header *channel;
19 		unsigned int position;
20 		dma_addr_t phys;
21 	} rx, tx;
22 
23 	void (*notify)(struct tegra_ivc *ivc, void *data);
24 	void *notify_data;
25 
26 	unsigned int num_frames;
27 	size_t frame_size;
28 };
29 
30 /**
31  * tegra_ivc_read_get_next_frame - Peek at the next frame to receive
32  * @ivc		pointer of the IVC channel
33  *
34  * Peek at the next frame to be received, without removing it from
35  * the queue.
36  *
37  * Returns a pointer to the frame, or an error encoded pointer.
38  */
39 void *tegra_ivc_read_get_next_frame(struct tegra_ivc *ivc);
40 
41 /**
42  * tegra_ivc_read_advance - Advance the read queue
43  * @ivc		pointer of the IVC channel
44  *
45  * Advance the read queue
46  *
47  * Returns 0, or a negative error value if failed.
48  */
49 int tegra_ivc_read_advance(struct tegra_ivc *ivc);
50 
51 /**
52  * tegra_ivc_write_get_next_frame - Poke at the next frame to transmit
53  * @ivc		pointer of the IVC channel
54  *
55  * Get access to the next frame.
56  *
57  * Returns a pointer to the frame, or an error encoded pointer.
58  */
59 void *tegra_ivc_write_get_next_frame(struct tegra_ivc *ivc);
60 
61 /**
62  * tegra_ivc_write_advance - Advance the write queue
63  * @ivc		pointer of the IVC channel
64  *
65  * Advance the write queue
66  *
67  * Returns 0, or a negative error value if failed.
68  */
69 int tegra_ivc_write_advance(struct tegra_ivc *ivc);
70 
71 /**
72  * tegra_ivc_notified - handle internal messages
73  * @ivc		pointer of the IVC channel
74  *
75  * This function must be called following every notification.
76  *
77  * Returns 0 if the channel is ready for communication, or -EAGAIN if a channel
78  * reset is in progress.
79  */
80 int tegra_ivc_notified(struct tegra_ivc *ivc);
81 
82 /**
83  * tegra_ivc_reset - initiates a reset of the shared memory state
84  * @ivc		pointer of the IVC channel
85  *
86  * This function must be called after a channel is reserved before it is used
87  * for communication. The channel will be ready for use when a subsequent call
88  * to notify the remote of the channel reset.
89  */
90 void tegra_ivc_reset(struct tegra_ivc *ivc);
91 
92 size_t tegra_ivc_align(size_t size);
93 unsigned tegra_ivc_total_queue_size(unsigned queue_size);
94 int tegra_ivc_init(struct tegra_ivc *ivc, struct device *peer, void *rx,
95 		   dma_addr_t rx_phys, void *tx, dma_addr_t tx_phys,
96 		   unsigned int num_frames, size_t frame_size,
97 		   void (*notify)(struct tegra_ivc *ivc, void *data),
98 		   void *data);
99 void tegra_ivc_cleanup(struct tegra_ivc *ivc);
100 
101 #endif /* __TEGRA_IVC_H */
102