1/* SPDX-License-Identifier: GPL-2.0 */
2/*
3 * System Control and Management Interface (SCMI) Message Protocol
4 * protocols common header file containing some definitions, structures
5 * and function prototypes used in all the different SCMI protocols.
6 *
7 * Copyright (C) 2022 ARM Ltd.
8 */
9#ifndef _SCMI_PROTOCOLS_H
10#define _SCMI_PROTOCOLS_H
11
12#include <linux/bitfield.h>
13#include <linux/completion.h>
14#include <linux/device.h>
15#include <linux/errno.h>
16#include <linux/kernel.h>
17#include <linux/hashtable.h>
18#include <linux/list.h>
19#include <linux/module.h>
20#include <linux/refcount.h>
21#include <linux/scmi_protocol.h>
22#include <linux/spinlock.h>
23#include <linux/types.h>
24
25#include <asm/unaligned.h>
26
27#define PROTOCOL_REV_MINOR_MASK GENMASK(15, 0)
28#define PROTOCOL_REV_MAJOR_MASK GENMASK(31, 16)
29#define PROTOCOL_REV_MAJOR(x) ((u16)(FIELD_GET(PROTOCOL_REV_MAJOR_MASK, (x))))
30#define PROTOCOL_REV_MINOR(x) ((u16)(FIELD_GET(PROTOCOL_REV_MINOR_MASK, (x))))
31
32enum scmi_common_cmd {
33 PROTOCOL_VERSION = 0x0,
34 PROTOCOL_ATTRIBUTES = 0x1,
35 PROTOCOL_MESSAGE_ATTRIBUTES = 0x2,
36 NEGOTIATE_PROTOCOL_VERSION = 0x10,
37};
38
39/**
40 * struct scmi_msg_resp_prot_version - Response for a message
41 *
42 * @minor_version: Minor version of the ABI that firmware supports
43 * @major_version: Major version of the ABI that firmware supports
44 *
45 * In general, ABI version changes follow the rule that minor version increments
46 * are backward compatible. Major revision changes in ABI may not be
47 * backward compatible.
48 *
49 * Response to a generic message with message type SCMI_MSG_VERSION
50 */
51struct scmi_msg_resp_prot_version {
52 __le16 minor_version;
53 __le16 major_version;
54};
55
56/**
57 * struct scmi_msg - Message(Tx/Rx) structure
58 *
59 * @buf: Buffer pointer
60 * @len: Length of data in the Buffer
61 */
62struct scmi_msg {
63 void *buf;
64 size_t len;
65};
66
67/**
68 * struct scmi_msg_hdr - Message(Tx/Rx) header
69 *
70 * @id: The identifier of the message being sent
71 * @protocol_id: The identifier of the protocol used to send @id message
72 * @type: The SCMI type for this message
73 * @seq: The token to identify the message. When a message returns, the
74 * platform returns the whole message header unmodified including the
75 * token
76 * @status: Status of the transfer once it's complete
77 * @poll_completion: Indicate if the transfer needs to be polled for
78 * completion or interrupt mode is used
79 */
80struct scmi_msg_hdr {
81 u8 id;
82 u8 protocol_id;
83 u8 type;
84 u16 seq;
85 u32 status;
86 bool poll_completion;
87};
88
89/**
90 * struct scmi_xfer - Structure representing a message flow
91 *
92 * @transfer_id: Unique ID for debug & profiling purpose
93 * @hdr: Transmit message header
94 * @tx: Transmit message
95 * @rx: Receive message, the buffer should be pre-allocated to store
96 * message. If request-ACK protocol is used, we can reuse the same
97 * buffer for the rx path as we use for the tx path.
98 * @done: command message transmit completion event
99 * @async_done: pointer to delayed response message received event completion
100 * @pending: True for xfers added to @pending_xfers hashtable
101 * @node: An hlist_node reference used to store this xfer, alternatively, on
102 * the free list @free_xfers or in the @pending_xfers hashtable
103 * @users: A refcount to track the active users for this xfer.
104 * This is meant to protect against the possibility that, when a command
105 * transaction times out concurrently with the reception of a valid
106 * response message, the xfer could be finally put on the TX path, and
107 * so vanish, while on the RX path scmi_rx_callback() is still
108 * processing it: in such a case this refcounting will ensure that, even
109 * though the timed-out transaction will anyway cause the command
110 * request to be reported as failed by time-out, the underlying xfer
111 * cannot be discarded and possibly reused until the last one user on
112 * the RX path has released it.
113 * @busy: An atomic flag to ensure exclusive write access to this xfer
114 * @state: The current state of this transfer, with states transitions deemed
115 * valid being:
116 * - SCMI_XFER_SENT_OK -> SCMI_XFER_RESP_OK [ -> SCMI_XFER_DRESP_OK ]
117 * - SCMI_XFER_SENT_OK -> SCMI_XFER_DRESP_OK
118 * (Missing synchronous response is assumed OK and ignored)
119 * @flags: Optional flags associated to this xfer.
120 * @lock: A spinlock to protect state and busy fields.
121 * @priv: A pointer for transport private usage.
122 */
123struct scmi_xfer {
124 int transfer_id;
125 struct scmi_msg_hdr hdr;
126 struct scmi_msg tx;
127 struct scmi_msg rx;
128 struct completion done;
129 struct completion *async_done;
130 bool pending;
131 struct hlist_node node;
132 refcount_t users;
133#define SCMI_XFER_FREE 0
134#define SCMI_XFER_BUSY 1
135 atomic_t busy;
136#define SCMI_XFER_SENT_OK 0
137#define SCMI_XFER_RESP_OK 1
138#define SCMI_XFER_DRESP_OK 2
139 int state;
140#define SCMI_XFER_FLAG_IS_RAW BIT(0)
141#define SCMI_XFER_IS_RAW(x) ((x)->flags & SCMI_XFER_FLAG_IS_RAW)
142#define SCMI_XFER_FLAG_CHAN_SET BIT(1)
143#define SCMI_XFER_IS_CHAN_SET(x) \
144 ((x)->flags & SCMI_XFER_FLAG_CHAN_SET)
145 int flags;
146 /* A lock to protect state and busy fields */
147 spinlock_t lock;
148 void *priv;
149};
150
151struct scmi_xfer_ops;
152struct scmi_proto_helpers_ops;
153
154/**
155 * struct scmi_protocol_handle - Reference to an initialized protocol instance
156 *
157 * @dev: A reference to the associated SCMI instance device (handle->dev).
158 * @xops: A reference to a struct holding refs to the core xfer operations that
159 * can be used by the protocol implementation to generate SCMI messages.
160 * @set_priv: A method to set protocol private data for this instance.
161 * @get_priv: A method to get protocol private data previously set.
162 *
163 * This structure represents a protocol initialized against specific SCMI
164 * instance and it will be used as follows:
165 * - as a parameter fed from the core to the protocol initialization code so
166 * that it can access the core xfer operations to build and generate SCMI
167 * messages exclusively for the specific underlying protocol instance.
168 * - as an opaque handle fed by an SCMI driver user when it tries to access
169 * this protocol through its own protocol operations.
170 * In this case this handle will be returned as an opaque object together
171 * with the related protocol operations when the SCMI driver tries to access
172 * the protocol.
173 */
174struct scmi_protocol_handle {
175 struct device *dev;
176 const struct scmi_xfer_ops *xops;
177 const struct scmi_proto_helpers_ops *hops;
178 int (*set_priv)(const struct scmi_protocol_handle *ph, void *priv,
179 u32 version);
180 void *(*get_priv)(const struct scmi_protocol_handle *ph);
181};
182
183/**
184 * struct scmi_iterator_state - Iterator current state descriptor
185 * @desc_index: Starting index for the current mulit-part request.
186 * @num_returned: Number of returned items in the last multi-part reply.
187 * @num_remaining: Number of remaining items in the multi-part message.
188 * @max_resources: Maximum acceptable number of items, configured by the caller
189 * depending on the underlying resources that it is querying.
190 * @loop_idx: The iterator loop index in the current multi-part reply.
191 * @rx_len: Size in bytes of the currenly processed message; it can be used by
192 * the user of the iterator to verify a reply size.
193 * @priv: Optional pointer to some additional state-related private data setup
194 * by the caller during the iterations.
195 */
196struct scmi_iterator_state {
197 unsigned int desc_index;
198 unsigned int num_returned;
199 unsigned int num_remaining;
200 unsigned int max_resources;
201 unsigned int loop_idx;
202 size_t rx_len;
203 void *priv;
204};
205
206/**
207 * struct scmi_iterator_ops - Custom iterator operations
208 * @prepare_message: An operation to provide the custom logic to fill in the
209 * SCMI command request pointed by @message. @desc_index is
210 * a reference to the next index to use in the multi-part
211 * request.
212 * @update_state: An operation to provide the custom logic to update the
213 * iterator state from the actual message response.
214 * @process_response: An operation to provide the custom logic needed to process
215 * each chunk of the multi-part message.
216 */
217struct scmi_iterator_ops {
218 void (*prepare_message)(void *message, unsigned int desc_index,
219 const void *priv);
220 int (*update_state)(struct scmi_iterator_state *st,
221 const void *response, void *priv);
222 int (*process_response)(const struct scmi_protocol_handle *ph,
223 const void *response,
224 struct scmi_iterator_state *st, void *priv);
225};
226
227struct scmi_fc_db_info {
228 int width;
229 u64 set;
230 u64 mask;
231 void __iomem *addr;
232};
233
234struct scmi_fc_info {
235 void __iomem *set_addr;
236 void __iomem *get_addr;
237 struct scmi_fc_db_info *set_db;
238 u32 rate_limit;
239};
240
241/**
242 * struct scmi_proto_helpers_ops - References to common protocol helpers
243 * @extended_name_get: A common helper function to retrieve extended naming
244 * for the specified resource using the specified command.
245 * Result is returned as a NULL terminated string in the
246 * pre-allocated area pointed to by @name with maximum
247 * capacity of @len bytes.
248 * @iter_response_init: A common helper to initialize a generic iterator to
249 * parse multi-message responses: when run the iterator
250 * will take care to send the initial command request as
251 * specified by @msg_id and @tx_size and then to parse the
252 * multi-part responses using the custom operations
253 * provided in @ops.
254 * @iter_response_run: A common helper to trigger the run of a previously
255 * initialized iterator.
256 * @protocol_msg_check: A common helper to check is a specific protocol message
257 * is supported.
258 * @fastchannel_init: A common helper used to initialize FC descriptors by
259 * gathering FC descriptions from the SCMI platform server.
260 * @fastchannel_db_ring: A common helper to ring a FC doorbell.
261 */
262struct scmi_proto_helpers_ops {
263 int (*extended_name_get)(const struct scmi_protocol_handle *ph,
264 u8 cmd_id, u32 res_id, u32 *flags, char *name,
265 size_t len);
266 void *(*iter_response_init)(const struct scmi_protocol_handle *ph,
267 struct scmi_iterator_ops *ops,
268 unsigned int max_resources, u8 msg_id,
269 size_t tx_size, void *priv);
270 int (*iter_response_run)(void *iter);
271 int (*protocol_msg_check)(const struct scmi_protocol_handle *ph,
272 u32 message_id, u32 *attributes);
273 void (*fastchannel_init)(const struct scmi_protocol_handle *ph,
274 u8 describe_id, u32 message_id,
275 u32 valid_size, u32 domain,
276 void __iomem **p_addr,
277 struct scmi_fc_db_info **p_db,
278 u32 *rate_limit);
279 void (*fastchannel_db_ring)(struct scmi_fc_db_info *db);
280};
281
282/**
283 * struct scmi_xfer_ops - References to the core SCMI xfer operations.
284 * @version_get: Get this version protocol.
285 * @xfer_get_init: Initialize one struct xfer if any xfer slot is free.
286 * @reset_rx_to_maxsz: Reset rx size to max transport size.
287 * @do_xfer: Do the SCMI transfer.
288 * @do_xfer_with_response: Do the SCMI transfer waiting for a response.
289 * @xfer_put: Free the xfer slot.
290 *
291 * Note that all this operations expect a protocol handle as first parameter;
292 * they then internally use it to infer the underlying protocol number: this
293 * way is not possible for a protocol implementation to forge messages for
294 * another protocol.
295 */
296struct scmi_xfer_ops {
297 int (*version_get)(const struct scmi_protocol_handle *ph, u32 *version);
298 int (*xfer_get_init)(const struct scmi_protocol_handle *ph, u8 msg_id,
299 size_t tx_size, size_t rx_size,
300 struct scmi_xfer **p);
301 void (*reset_rx_to_maxsz)(const struct scmi_protocol_handle *ph,
302 struct scmi_xfer *xfer);
303 int (*do_xfer)(const struct scmi_protocol_handle *ph,
304 struct scmi_xfer *xfer);
305 int (*do_xfer_with_response)(const struct scmi_protocol_handle *ph,
306 struct scmi_xfer *xfer);
307 void (*xfer_put)(const struct scmi_protocol_handle *ph,
308 struct scmi_xfer *xfer);
309};
310
311typedef int (*scmi_prot_init_ph_fn_t)(const struct scmi_protocol_handle *);
312
313/**
314 * struct scmi_protocol - Protocol descriptor
315 * @id: Protocol ID.
316 * @owner: Module reference if any.
317 * @instance_init: Mandatory protocol initialization function.
318 * @instance_deinit: Optional protocol de-initialization function.
319 * @ops: Optional reference to the operations provided by the protocol and
320 * exposed in scmi_protocol.h.
321 * @events: An optional reference to the events supported by this protocol.
322 * @supported_version: The highest version currently supported for this
323 * protocol by the agent. Each protocol implementation
324 * in the agent is supposed to downgrade to match the
325 * protocol version supported by the platform.
326 */
327struct scmi_protocol {
328 const u8 id;
329 struct module *owner;
330 const scmi_prot_init_ph_fn_t instance_init;
331 const scmi_prot_init_ph_fn_t instance_deinit;
332 const void *ops;
333 const struct scmi_protocol_events *events;
334 unsigned int supported_version;
335};
336
337#define DEFINE_SCMI_PROTOCOL_REGISTER_UNREGISTER(name, proto) \
338static const struct scmi_protocol *__this_proto = &(proto); \
339 \
340int __init scmi_##name##_register(void) \
341{ \
342 return scmi_protocol_register(__this_proto); \
343} \
344 \
345void __exit scmi_##name##_unregister(void) \
346{ \
347 scmi_protocol_unregister(__this_proto); \
348}
349
350#define DECLARE_SCMI_REGISTER_UNREGISTER(func) \
351 int __init scmi_##func##_register(void); \
352 void __exit scmi_##func##_unregister(void)
353DECLARE_SCMI_REGISTER_UNREGISTER(base);
354DECLARE_SCMI_REGISTER_UNREGISTER(clock);
355DECLARE_SCMI_REGISTER_UNREGISTER(perf);
356DECLARE_SCMI_REGISTER_UNREGISTER(power);
357DECLARE_SCMI_REGISTER_UNREGISTER(reset);
358DECLARE_SCMI_REGISTER_UNREGISTER(sensors);
359DECLARE_SCMI_REGISTER_UNREGISTER(voltage);
360DECLARE_SCMI_REGISTER_UNREGISTER(system);
361DECLARE_SCMI_REGISTER_UNREGISTER(powercap);
362
363#endif /* _SCMI_PROTOCOLS_H */
364

source code of linux/drivers/firmware/arm_scmi/protocols.h