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 SCMI_SHORT_NAME_MAX_SIZE 16
29 #define PROTOCOL_REV_MINOR_MASK GENMASK(15, 0)
30 #define PROTOCOL_REV_MAJOR_MASK GENMASK(31, 16)
31 #define PROTOCOL_REV_MAJOR(x) ((u16)(FIELD_GET(PROTOCOL_REV_MAJOR_MASK, (x))))
32 #define PROTOCOL_REV_MINOR(x) ((u16)(FIELD_GET(PROTOCOL_REV_MINOR_MASK, (x))))
34 enum scmi_common_cmd {
35 PROTOCOL_VERSION = 0x0,
36 PROTOCOL_ATTRIBUTES = 0x1,
37 PROTOCOL_MESSAGE_ATTRIBUTES = 0x2,
41 * struct scmi_msg_resp_prot_version - Response for a message
43 * @minor_version: Minor version of the ABI that firmware supports
44 * @major_version: Major version of the ABI that firmware supports
46 * In general, ABI version changes follow the rule that minor version increments
47 * are backward compatible. Major revision changes in ABI may not be
48 * backward compatible.
50 * Response to a generic message with message type SCMI_MSG_VERSION
52 struct scmi_msg_resp_prot_version {
58 * struct scmi_msg - Message(Tx/Rx) structure
60 * @buf: Buffer pointer
61 * @len: Length of data in the Buffer
69 * struct scmi_msg_hdr - Message(Tx/Rx) header
71 * @id: The identifier of the message being sent
72 * @protocol_id: The identifier of the protocol used to send @id message
73 * @type: The SCMI type for this message
74 * @seq: The token to identify the message. When a message returns, the
75 * platform returns the whole message header unmodified including the
77 * @status: Status of the transfer once it's complete
78 * @poll_completion: Indicate if the transfer needs to be polled for
79 * completion or interrupt mode is used
91 * struct scmi_xfer - Structure representing a message flow
93 * @transfer_id: Unique ID for debug & profiling purpose
94 * @hdr: Transmit message header
95 * @tx: Transmit message
96 * @rx: Receive message, the buffer should be pre-allocated to store
97 * message. If request-ACK protocol is used, we can reuse the same
98 * buffer for the rx path as we use for the tx path.
99 * @done: command message transmit completion event
100 * @async_done: pointer to delayed response message received event completion
101 * @pending: True for xfers added to @pending_xfers hashtable
102 * @node: An hlist_node reference used to store this xfer, alternatively, on
103 * the free list @free_xfers or in the @pending_xfers hashtable
104 * @users: A refcount to track the active users for this xfer.
105 * This is meant to protect against the possibility that, when a command
106 * transaction times out concurrently with the reception of a valid
107 * response message, the xfer could be finally put on the TX path, and
108 * so vanish, while on the RX path scmi_rx_callback() is still
109 * processing it: in such a case this refcounting will ensure that, even
110 * though the timed-out transaction will anyway cause the command
111 * request to be reported as failed by time-out, the underlying xfer
112 * cannot be discarded and possibly reused until the last one user on
113 * the RX path has released it.
114 * @busy: An atomic flag to ensure exclusive write access to this xfer
115 * @state: The current state of this transfer, with states transitions deemed
117 * - SCMI_XFER_SENT_OK -> SCMI_XFER_RESP_OK [ -> SCMI_XFER_DRESP_OK ]
118 * - SCMI_XFER_SENT_OK -> SCMI_XFER_DRESP_OK
119 * (Missing synchronous response is assumed OK and ignored)
120 * @lock: A spinlock to protect state and busy fields.
121 * @priv: A pointer for transport private usage.
125 struct scmi_msg_hdr hdr;
128 struct completion done;
129 struct completion *async_done;
131 struct hlist_node node;
133 #define SCMI_XFER_FREE 0
134 #define SCMI_XFER_BUSY 1
136 #define SCMI_XFER_SENT_OK 0
137 #define SCMI_XFER_RESP_OK 1
138 #define SCMI_XFER_DRESP_OK 2
140 /* A lock to protect state and busy fields */
145 struct scmi_xfer_ops;
146 struct scmi_proto_helpers_ops;
149 * struct scmi_protocol_handle - Reference to an initialized protocol instance
151 * @dev: A reference to the associated SCMI instance device (handle->dev).
152 * @xops: A reference to a struct holding refs to the core xfer operations that
153 * can be used by the protocol implementation to generate SCMI messages.
154 * @set_priv: A method to set protocol private data for this instance.
155 * @get_priv: A method to get protocol private data previously set.
157 * This structure represents a protocol initialized against specific SCMI
158 * instance and it will be used as follows:
159 * - as a parameter fed from the core to the protocol initialization code so
160 * that it can access the core xfer operations to build and generate SCMI
161 * messages exclusively for the specific underlying protocol instance.
162 * - as an opaque handle fed by an SCMI driver user when it tries to access
163 * this protocol through its own protocol operations.
164 * In this case this handle will be returned as an opaque object together
165 * with the related protocol operations when the SCMI driver tries to access
168 struct scmi_protocol_handle {
170 const struct scmi_xfer_ops *xops;
171 const struct scmi_proto_helpers_ops *hops;
172 int (*set_priv)(const struct scmi_protocol_handle *ph, void *priv);
173 void *(*get_priv)(const struct scmi_protocol_handle *ph);
177 * struct scmi_iterator_state - Iterator current state descriptor
178 * @desc_index: Starting index for the current mulit-part request.
179 * @num_returned: Number of returned items in the last multi-part reply.
180 * @num_remaining: Number of remaining items in the multi-part message.
181 * @max_resources: Maximum acceptable number of items, configured by the caller
182 * depending on the underlying resources that it is querying.
183 * @loop_idx: The iterator loop index in the current multi-part reply.
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;
197 * struct scmi_iterator_ops - Custom iterator operations
198 * @prepare_message: An operation to provide the custom logic to fill in the
199 * SCMI command request pointed by @message. @desc_index is
200 * a reference to the next index to use in the multi-part
202 * @update_state: An operation to provide the custom logic to update the
203 * iterator state from the actual message response.
204 * @process_response: An operation to provide the custom logic needed to process
205 * each chunk of the multi-part message.
207 struct scmi_iterator_ops {
208 void (*prepare_message)(void *message, unsigned int desc_index,
210 int (*update_state)(struct scmi_iterator_state *st,
211 const void *response, void *priv);
212 int (*process_response)(const struct scmi_protocol_handle *ph,
213 const void *response,
214 struct scmi_iterator_state *st, void *priv);
218 * struct scmi_proto_helpers_ops - References to common protocol helpers
219 * @extended_name_get: A common helper function to retrieve extended naming
220 * for the specified resource using the specified command.
221 * Result is returned as a NULL terminated string in the
222 * pre-allocated area pointed to by @name with maximum
223 * capacity of @len bytes.
224 * @iter_response_init: A common helper to initialize a generic iterator to
225 * parse multi-message responses: when run the iterator
226 * will take care to send the initial command request as
227 * specified by @msg_id and @tx_size and then to parse the
228 * multi-part responses using the custom operations
230 * @iter_response_run: A common helper to trigger the run of a previously
231 * initialized iterator.
233 struct scmi_proto_helpers_ops {
234 int (*extended_name_get)(const struct scmi_protocol_handle *ph,
235 u8 cmd_id, u32 res_id, char *name, size_t len);
236 void *(*iter_response_init)(const struct scmi_protocol_handle *ph,
237 struct scmi_iterator_ops *ops,
238 unsigned int max_resources, u8 msg_id,
239 size_t tx_size, void *priv);
240 int (*iter_response_run)(void *iter);
244 * struct scmi_xfer_ops - References to the core SCMI xfer operations.
245 * @version_get: Get this version protocol.
246 * @xfer_get_init: Initialize one struct xfer if any xfer slot is free.
247 * @reset_rx_to_maxsz: Reset rx size to max transport size.
248 * @do_xfer: Do the SCMI transfer.
249 * @do_xfer_with_response: Do the SCMI transfer waiting for a response.
250 * @xfer_put: Free the xfer slot.
252 * Note that all this operations expect a protocol handle as first parameter;
253 * they then internally use it to infer the underlying protocol number: this
254 * way is not possible for a protocol implementation to forge messages for
257 struct scmi_xfer_ops {
258 int (*version_get)(const struct scmi_protocol_handle *ph, u32 *version);
259 int (*xfer_get_init)(const struct scmi_protocol_handle *ph, u8 msg_id,
260 size_t tx_size, size_t rx_size,
261 struct scmi_xfer **p);
262 void (*reset_rx_to_maxsz)(const struct scmi_protocol_handle *ph,
263 struct scmi_xfer *xfer);
264 int (*do_xfer)(const struct scmi_protocol_handle *ph,
265 struct scmi_xfer *xfer);
266 int (*do_xfer_with_response)(const struct scmi_protocol_handle *ph,
267 struct scmi_xfer *xfer);
268 void (*xfer_put)(const struct scmi_protocol_handle *ph,
269 struct scmi_xfer *xfer);
272 typedef int (*scmi_prot_init_ph_fn_t)(const struct scmi_protocol_handle *);
275 * struct scmi_protocol - Protocol descriptor
277 * @owner: Module reference if any.
278 * @instance_init: Mandatory protocol initialization function.
279 * @instance_deinit: Optional protocol de-initialization function.
280 * @ops: Optional reference to the operations provided by the protocol and
281 * exposed in scmi_protocol.h.
282 * @events: An optional reference to the events supported by this protocol.
284 struct scmi_protocol {
286 struct module *owner;
287 const scmi_prot_init_ph_fn_t instance_init;
288 const scmi_prot_init_ph_fn_t instance_deinit;
290 const struct scmi_protocol_events *events;
293 #define DEFINE_SCMI_PROTOCOL_REGISTER_UNREGISTER(name, proto) \
294 static const struct scmi_protocol *__this_proto = &(proto); \
296 int __init scmi_##name##_register(void) \
298 return scmi_protocol_register(__this_proto); \
301 void __exit scmi_##name##_unregister(void) \
303 scmi_protocol_unregister(__this_proto); \
306 #define DECLARE_SCMI_REGISTER_UNREGISTER(func) \
307 int __init scmi_##func##_register(void); \
308 void __exit scmi_##func##_unregister(void)
309 DECLARE_SCMI_REGISTER_UNREGISTER(base);
310 DECLARE_SCMI_REGISTER_UNREGISTER(clock);
311 DECLARE_SCMI_REGISTER_UNREGISTER(perf);
312 DECLARE_SCMI_REGISTER_UNREGISTER(power);
313 DECLARE_SCMI_REGISTER_UNREGISTER(reset);
314 DECLARE_SCMI_REGISTER_UNREGISTER(sensors);
315 DECLARE_SCMI_REGISTER_UNREGISTER(voltage);
316 DECLARE_SCMI_REGISTER_UNREGISTER(system);
318 #endif /* _SCMI_PROTOCOLS_H */