1 /* SPDX-License-Identifier: GPL-2.0 */
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.
7 * Copyright (C) 2022 ARM Ltd.
9 #ifndef _SCMI_PROTOCOLS_H
10 #define _SCMI_PROTOCOLS_H
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>
25 #include <asm/unaligned.h>
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))))
32 enum scmi_common_cmd {
33 PROTOCOL_VERSION = 0x0,
34 PROTOCOL_ATTRIBUTES = 0x1,
35 PROTOCOL_MESSAGE_ATTRIBUTES = 0x2,
39 * struct scmi_msg_resp_prot_version - Response for a message
41 * @minor_version: Minor version of the ABI that firmware supports
42 * @major_version: Major version of the ABI that firmware supports
44 * In general, ABI version changes follow the rule that minor version increments
45 * are backward compatible. Major revision changes in ABI may not be
46 * backward compatible.
48 * Response to a generic message with message type SCMI_MSG_VERSION
50 struct scmi_msg_resp_prot_version {
56 * struct scmi_msg - Message(Tx/Rx) structure
58 * @buf: Buffer pointer
59 * @len: Length of data in the Buffer
67 * struct scmi_msg_hdr - Message(Tx/Rx) header
69 * @id: The identifier of the message being sent
70 * @protocol_id: The identifier of the protocol used to send @id message
71 * @type: The SCMI type for this message
72 * @seq: The token to identify the message. When a message returns, the
73 * platform returns the whole message header unmodified including the
75 * @status: Status of the transfer once it's complete
76 * @poll_completion: Indicate if the transfer needs to be polled for
77 * completion or interrupt mode is used
89 * struct scmi_xfer - Structure representing a message flow
91 * @transfer_id: Unique ID for debug & profiling purpose
92 * @hdr: Transmit message header
93 * @tx: Transmit message
94 * @rx: Receive message, the buffer should be pre-allocated to store
95 * message. If request-ACK protocol is used, we can reuse the same
96 * buffer for the rx path as we use for the tx path.
97 * @done: command message transmit completion event
98 * @async_done: pointer to delayed response message received event completion
99 * @pending: True for xfers added to @pending_xfers hashtable
100 * @node: An hlist_node reference used to store this xfer, alternatively, on
101 * the free list @free_xfers or in the @pending_xfers hashtable
102 * @users: A refcount to track the active users for this xfer.
103 * This is meant to protect against the possibility that, when a command
104 * transaction times out concurrently with the reception of a valid
105 * response message, the xfer could be finally put on the TX path, and
106 * so vanish, while on the RX path scmi_rx_callback() is still
107 * processing it: in such a case this refcounting will ensure that, even
108 * though the timed-out transaction will anyway cause the command
109 * request to be reported as failed by time-out, the underlying xfer
110 * cannot be discarded and possibly reused until the last one user on
111 * the RX path has released it.
112 * @busy: An atomic flag to ensure exclusive write access to this xfer
113 * @state: The current state of this transfer, with states transitions deemed
115 * - SCMI_XFER_SENT_OK -> SCMI_XFER_RESP_OK [ -> SCMI_XFER_DRESP_OK ]
116 * - SCMI_XFER_SENT_OK -> SCMI_XFER_DRESP_OK
117 * (Missing synchronous response is assumed OK and ignored)
118 * @lock: A spinlock to protect state and busy fields.
119 * @priv: A pointer for transport private usage.
123 struct scmi_msg_hdr hdr;
126 struct completion done;
127 struct completion *async_done;
129 struct hlist_node node;
131 #define SCMI_XFER_FREE 0
132 #define SCMI_XFER_BUSY 1
134 #define SCMI_XFER_SENT_OK 0
135 #define SCMI_XFER_RESP_OK 1
136 #define SCMI_XFER_DRESP_OK 2
138 /* A lock to protect state and busy fields */
143 struct scmi_xfer_ops;
144 struct scmi_proto_helpers_ops;
147 * struct scmi_protocol_handle - Reference to an initialized protocol instance
149 * @dev: A reference to the associated SCMI instance device (handle->dev).
150 * @xops: A reference to a struct holding refs to the core xfer operations that
151 * can be used by the protocol implementation to generate SCMI messages.
152 * @set_priv: A method to set protocol private data for this instance.
153 * @get_priv: A method to get protocol private data previously set.
155 * This structure represents a protocol initialized against specific SCMI
156 * instance and it will be used as follows:
157 * - as a parameter fed from the core to the protocol initialization code so
158 * that it can access the core xfer operations to build and generate SCMI
159 * messages exclusively for the specific underlying protocol instance.
160 * - as an opaque handle fed by an SCMI driver user when it tries to access
161 * this protocol through its own protocol operations.
162 * In this case this handle will be returned as an opaque object together
163 * with the related protocol operations when the SCMI driver tries to access
166 struct scmi_protocol_handle {
168 const struct scmi_xfer_ops *xops;
169 const struct scmi_proto_helpers_ops *hops;
170 int (*set_priv)(const struct scmi_protocol_handle *ph, void *priv);
171 void *(*get_priv)(const struct scmi_protocol_handle *ph);
175 * struct scmi_iterator_state - Iterator current state descriptor
176 * @desc_index: Starting index for the current mulit-part request.
177 * @num_returned: Number of returned items in the last multi-part reply.
178 * @num_remaining: Number of remaining items in the multi-part message.
179 * @max_resources: Maximum acceptable number of items, configured by the caller
180 * depending on the underlying resources that it is querying.
181 * @loop_idx: The iterator loop index in the current multi-part reply.
182 * @rx_len: Size in bytes of the currenly processed message; it can be used by
183 * the user of the iterator to verify a reply size.
184 * @priv: Optional pointer to some additional state-related private data setup
185 * by the caller during the iterations.
187 struct scmi_iterator_state {
188 unsigned int desc_index;
189 unsigned int num_returned;
190 unsigned int num_remaining;
191 unsigned int max_resources;
192 unsigned int loop_idx;
198 * struct scmi_iterator_ops - Custom iterator operations
199 * @prepare_message: An operation to provide the custom logic to fill in the
200 * SCMI command request pointed by @message. @desc_index is
201 * a reference to the next index to use in the multi-part
203 * @update_state: An operation to provide the custom logic to update the
204 * iterator state from the actual message response.
205 * @process_response: An operation to provide the custom logic needed to process
206 * each chunk of the multi-part message.
208 struct scmi_iterator_ops {
209 void (*prepare_message)(void *message, unsigned int desc_index,
211 int (*update_state)(struct scmi_iterator_state *st,
212 const void *response, void *priv);
213 int (*process_response)(const struct scmi_protocol_handle *ph,
214 const void *response,
215 struct scmi_iterator_state *st, void *priv);
219 * struct scmi_proto_helpers_ops - References to common protocol helpers
220 * @extended_name_get: A common helper function to retrieve extended naming
221 * for the specified resource using the specified command.
222 * Result is returned as a NULL terminated string in the
223 * pre-allocated area pointed to by @name with maximum
224 * capacity of @len bytes.
225 * @iter_response_init: A common helper to initialize a generic iterator to
226 * parse multi-message responses: when run the iterator
227 * will take care to send the initial command request as
228 * specified by @msg_id and @tx_size and then to parse the
229 * multi-part responses using the custom operations
231 * @iter_response_run: A common helper to trigger the run of a previously
232 * initialized iterator.
234 struct scmi_proto_helpers_ops {
235 int (*extended_name_get)(const struct scmi_protocol_handle *ph,
236 u8 cmd_id, u32 res_id, char *name, size_t len);
237 void *(*iter_response_init)(const struct scmi_protocol_handle *ph,
238 struct scmi_iterator_ops *ops,
239 unsigned int max_resources, u8 msg_id,
240 size_t tx_size, void *priv);
241 int (*iter_response_run)(void *iter);
245 * struct scmi_xfer_ops - References to the core SCMI xfer operations.
246 * @version_get: Get this version protocol.
247 * @xfer_get_init: Initialize one struct xfer if any xfer slot is free.
248 * @reset_rx_to_maxsz: Reset rx size to max transport size.
249 * @do_xfer: Do the SCMI transfer.
250 * @do_xfer_with_response: Do the SCMI transfer waiting for a response.
251 * @xfer_put: Free the xfer slot.
253 * Note that all this operations expect a protocol handle as first parameter;
254 * they then internally use it to infer the underlying protocol number: this
255 * way is not possible for a protocol implementation to forge messages for
258 struct scmi_xfer_ops {
259 int (*version_get)(const struct scmi_protocol_handle *ph, u32 *version);
260 int (*xfer_get_init)(const struct scmi_protocol_handle *ph, u8 msg_id,
261 size_t tx_size, size_t rx_size,
262 struct scmi_xfer **p);
263 void (*reset_rx_to_maxsz)(const struct scmi_protocol_handle *ph,
264 struct scmi_xfer *xfer);
265 int (*do_xfer)(const struct scmi_protocol_handle *ph,
266 struct scmi_xfer *xfer);
267 int (*do_xfer_with_response)(const struct scmi_protocol_handle *ph,
268 struct scmi_xfer *xfer);
269 void (*xfer_put)(const struct scmi_protocol_handle *ph,
270 struct scmi_xfer *xfer);
273 typedef int (*scmi_prot_init_ph_fn_t)(const struct scmi_protocol_handle *);
276 * struct scmi_protocol - Protocol descriptor
278 * @owner: Module reference if any.
279 * @instance_init: Mandatory protocol initialization function.
280 * @instance_deinit: Optional protocol de-initialization function.
281 * @ops: Optional reference to the operations provided by the protocol and
282 * exposed in scmi_protocol.h.
283 * @events: An optional reference to the events supported by this protocol.
285 struct scmi_protocol {
287 struct module *owner;
288 const scmi_prot_init_ph_fn_t instance_init;
289 const scmi_prot_init_ph_fn_t instance_deinit;
291 const struct scmi_protocol_events *events;
294 #define DEFINE_SCMI_PROTOCOL_REGISTER_UNREGISTER(name, proto) \
295 static const struct scmi_protocol *__this_proto = &(proto); \
297 int __init scmi_##name##_register(void) \
299 return scmi_protocol_register(__this_proto); \
302 void __exit scmi_##name##_unregister(void) \
304 scmi_protocol_unregister(__this_proto); \
307 #define DECLARE_SCMI_REGISTER_UNREGISTER(func) \
308 int __init scmi_##func##_register(void); \
309 void __exit scmi_##func##_unregister(void)
310 DECLARE_SCMI_REGISTER_UNREGISTER(base);
311 DECLARE_SCMI_REGISTER_UNREGISTER(clock);
312 DECLARE_SCMI_REGISTER_UNREGISTER(perf);
313 DECLARE_SCMI_REGISTER_UNREGISTER(power);
314 DECLARE_SCMI_REGISTER_UNREGISTER(reset);
315 DECLARE_SCMI_REGISTER_UNREGISTER(sensors);
316 DECLARE_SCMI_REGISTER_UNREGISTER(voltage);
317 DECLARE_SCMI_REGISTER_UNREGISTER(system);
319 #endif /* _SCMI_PROTOCOLS_H */