1/* SPDX-License-Identifier: GPL-2.0-only OR MIT */
2/*
3 * Apple RTKit IPC Library
4 * Copyright (C) The Asahi Linux Contributors
5 *
6 * Apple's SoCs come with various co-processors running their RTKit operating
7 * system. This protocol library is used by client drivers to use the
8 * features provided by them.
9 */
10#ifndef _LINUX_APPLE_RTKIT_H_
11#define _LINUX_APPLE_RTKIT_H_
12
13#include <linux/device.h>
14#include <linux/types.h>
15#include <linux/mailbox_client.h>
16
17/*
18 * Struct to represent implementation-specific RTKit operations.
19 *
20 * @buffer:    Shared memory buffer allocated inside normal RAM.
21 * @iomem:     Shared memory buffer controlled by the co-processors.
22 * @size:      Size of the shared memory buffer.
23 * @iova:      Device VA of shared memory buffer.
24 * @is_mapped: Shared memory buffer is managed by the co-processor.
25 * @private:   Private data pointer for the parent driver.
26 */
27
28struct apple_rtkit_shmem {
29	void *buffer;
30	void __iomem *iomem;
31	size_t size;
32	dma_addr_t iova;
33	bool is_mapped;
34	void *private;
35};
36
37/*
38 * Struct to represent implementation-specific RTKit operations.
39 *
40 * @crashed:       Called when the co-processor has crashed. Runs in process
41 *                 context.
42 * @recv_message:  Function called when a message from RTKit is received
43 *                 on a non-system endpoint. Called from a worker thread.
44 * @recv_message_early:
45 *                 Like recv_message, but called from atomic context. It
46 *                 should return true if it handled the message. If it
47 *                 returns false, the message will be passed on to the
48 *                 worker thread.
49 * @shmem_setup:   Setup shared memory buffer. If bfr.is_iomem is true the
50 *                 buffer is managed by the co-processor and needs to be mapped.
51 *                 Otherwise the buffer is managed by Linux and needs to be
52 *                 allocated. If not specified dma_alloc_coherent is used.
53 *                 Called in process context.
54 * @shmem_destroy: Undo the shared memory buffer setup in shmem_setup. If not
55 *                 specified dma_free_coherent is used. Called in process
56 *                 context.
57 */
58struct apple_rtkit_ops {
59	void (*crashed)(void *cookie);
60	void (*recv_message)(void *cookie, u8 endpoint, u64 message);
61	bool (*recv_message_early)(void *cookie, u8 endpoint, u64 message);
62	int (*shmem_setup)(void *cookie, struct apple_rtkit_shmem *bfr);
63	void (*shmem_destroy)(void *cookie, struct apple_rtkit_shmem *bfr);
64};
65
66struct apple_rtkit;
67
68/*
69 * Initializes the internal state required to handle RTKit. This
70 * should usually be called within _probe.
71 *
72 * @dev:         Pointer to the device node this coprocessor is assocated with
73 * @cookie:      opaque cookie passed to all functions defined in rtkit_ops
74 * @mbox_name:   mailbox name used to communicate with the co-processor
75 * @mbox_idx:    mailbox index to be used if mbox_name is NULL
76 * @ops:         pointer to rtkit_ops to be used for this co-processor
77 */
78struct apple_rtkit *devm_apple_rtkit_init(struct device *dev, void *cookie,
79					  const char *mbox_name, int mbox_idx,
80					  const struct apple_rtkit_ops *ops);
81
82/*
83 * Non-devm version of devm_apple_rtkit_init. Must be freed with
84 * apple_rtkit_free.
85 *
86 * @dev:         Pointer to the device node this coprocessor is assocated with
87 * @cookie:      opaque cookie passed to all functions defined in rtkit_ops
88 * @mbox_name:   mailbox name used to communicate with the co-processor
89 * @mbox_idx:    mailbox index to be used if mbox_name is NULL
90 * @ops:         pointer to rtkit_ops to be used for this co-processor
91 */
92struct apple_rtkit *apple_rtkit_init(struct device *dev, void *cookie,
93					  const char *mbox_name, int mbox_idx,
94					  const struct apple_rtkit_ops *ops);
95
96/*
97 * Free an instance of apple_rtkit.
98 */
99void apple_rtkit_free(struct apple_rtkit *rtk);
100
101/*
102 * Reinitialize internal structures. Must only be called with the co-processor
103 * is held in reset.
104 */
105int apple_rtkit_reinit(struct apple_rtkit *rtk);
106
107/*
108 * Handle RTKit's boot process. Should be called after the CPU of the
109 * co-processor has been started.
110 */
111int apple_rtkit_boot(struct apple_rtkit *rtk);
112
113/*
114 * Quiesce the co-processor.
115 */
116int apple_rtkit_quiesce(struct apple_rtkit *rtk);
117
118/*
119 * Wake the co-processor up from hibernation mode.
120 */
121int apple_rtkit_wake(struct apple_rtkit *rtk);
122
123/*
124 * Shutdown the co-processor
125 */
126int apple_rtkit_shutdown(struct apple_rtkit *rtk);
127
128/*
129 * Put the co-processor into idle mode
130 */
131int apple_rtkit_idle(struct apple_rtkit *rtk);
132
133/*
134 * Checks if RTKit is running and ready to handle messages.
135 */
136bool apple_rtkit_is_running(struct apple_rtkit *rtk);
137
138/*
139 * Checks if RTKit has crashed.
140 */
141bool apple_rtkit_is_crashed(struct apple_rtkit *rtk);
142
143/*
144 * Starts an endpoint. Must be called after boot but before any messages can be
145 * sent or received from that endpoint.
146 */
147int apple_rtkit_start_ep(struct apple_rtkit *rtk, u8 endpoint);
148
149/*
150 * Send a message to the given endpoint.
151 *
152 * @rtk:            RTKit reference
153 * @ep:             target endpoint
154 * @message:        message to be sent
155 * @completeion:    will be completed once the message has been submitted
156 *                  to the hardware FIFO. Can be NULL.
157 * @atomic:         if set to true this function can be called from atomic
158 *                  context.
159 */
160int apple_rtkit_send_message(struct apple_rtkit *rtk, u8 ep, u64 message,
161			     struct completion *completion, bool atomic);
162
163/*
164 * Process incoming messages in atomic context.
165 * This only guarantees that messages arrive as far as the recv_message_early
166 * callback; drivers expecting to handle incoming messages synchronously
167 * by calling this function must do it that way.
168 * Will return 1 if some data was processed, 0 if none was, or a
169 * negative error code on failure.
170 *
171 * @rtk:            RTKit reference
172 */
173int apple_rtkit_poll(struct apple_rtkit *rtk);
174
175#endif /* _LINUX_APPLE_RTKIT_H_ */
176