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 * @flags: Optional flags associated to this xfer.
119 * @lock: A spinlock to protect state and busy fields.
120 * @priv: A pointer for transport private usage.
124 struct scmi_msg_hdr hdr;
127 struct completion done;
128 struct completion *async_done;
130 struct hlist_node node;
132 #define SCMI_XFER_FREE 0
133 #define SCMI_XFER_BUSY 1
135 #define SCMI_XFER_SENT_OK 0
136 #define SCMI_XFER_RESP_OK 1
137 #define SCMI_XFER_DRESP_OK 2
139 #define SCMI_XFER_FLAG_IS_RAW BIT(0)
140 #define SCMI_XFER_IS_RAW(x) ((x)->flags & SCMI_XFER_FLAG_IS_RAW)
141 #define SCMI_XFER_FLAG_CHAN_SET BIT(1)
142 #define SCMI_XFER_IS_CHAN_SET(x) \
143 ((x)->flags & SCMI_XFER_FLAG_CHAN_SET)
145 /* A lock to protect state and busy fields */
150 struct scmi_xfer_ops;
151 struct scmi_proto_helpers_ops;
154 * struct scmi_protocol_handle - Reference to an initialized protocol instance
156 * @dev: A reference to the associated SCMI instance device (handle->dev).
157 * @xops: A reference to a struct holding refs to the core xfer operations that
158 * can be used by the protocol implementation to generate SCMI messages.
159 * @set_priv: A method to set protocol private data for this instance.
160 * @get_priv: A method to get protocol private data previously set.
162 * This structure represents a protocol initialized against specific SCMI
163 * instance and it will be used as follows:
164 * - as a parameter fed from the core to the protocol initialization code so
165 * that it can access the core xfer operations to build and generate SCMI
166 * messages exclusively for the specific underlying protocol instance.
167 * - as an opaque handle fed by an SCMI driver user when it tries to access
168 * this protocol through its own protocol operations.
169 * In this case this handle will be returned as an opaque object together
170 * with the related protocol operations when the SCMI driver tries to access
173 struct scmi_protocol_handle {
175 const struct scmi_xfer_ops *xops;
176 const struct scmi_proto_helpers_ops *hops;
177 int (*set_priv)(const struct scmi_protocol_handle *ph, void *priv,
179 void *(*get_priv)(const struct scmi_protocol_handle *ph);
183 * struct scmi_iterator_state - Iterator current state descriptor
184 * @desc_index: Starting index for the current mulit-part request.
185 * @num_returned: Number of returned items in the last multi-part reply.
186 * @num_remaining: Number of remaining items in the multi-part message.
187 * @max_resources: Maximum acceptable number of items, configured by the caller
188 * depending on the underlying resources that it is querying.
189 * @loop_idx: The iterator loop index in the current multi-part reply.
190 * @rx_len: Size in bytes of the currenly processed message; it can be used by
191 * the user of the iterator to verify a reply size.
192 * @priv: Optional pointer to some additional state-related private data setup
193 * by the caller during the iterations.
195 struct scmi_iterator_state {
196 unsigned int desc_index;
197 unsigned int num_returned;
198 unsigned int num_remaining;
199 unsigned int max_resources;
200 unsigned int loop_idx;
206 * struct scmi_iterator_ops - Custom iterator operations
207 * @prepare_message: An operation to provide the custom logic to fill in the
208 * SCMI command request pointed by @message. @desc_index is
209 * a reference to the next index to use in the multi-part
211 * @update_state: An operation to provide the custom logic to update the
212 * iterator state from the actual message response.
213 * @process_response: An operation to provide the custom logic needed to process
214 * each chunk of the multi-part message.
216 struct scmi_iterator_ops {
217 void (*prepare_message)(void *message, unsigned int desc_index,
219 int (*update_state)(struct scmi_iterator_state *st,
220 const void *response, void *priv);
221 int (*process_response)(const struct scmi_protocol_handle *ph,
222 const void *response,
223 struct scmi_iterator_state *st, void *priv);
226 struct scmi_fc_db_info {
233 struct scmi_fc_info {
234 void __iomem *set_addr;
235 void __iomem *get_addr;
236 struct scmi_fc_db_info *set_db;
240 * struct scmi_proto_helpers_ops - References to common protocol helpers
241 * @extended_name_get: A common helper function to retrieve extended naming
242 * for the specified resource using the specified command.
243 * Result is returned as a NULL terminated string in the
244 * pre-allocated area pointed to by @name with maximum
245 * capacity of @len bytes.
246 * @iter_response_init: A common helper to initialize a generic iterator to
247 * parse multi-message responses: when run the iterator
248 * will take care to send the initial command request as
249 * specified by @msg_id and @tx_size and then to parse the
250 * multi-part responses using the custom operations
252 * @iter_response_run: A common helper to trigger the run of a previously
253 * initialized iterator.
254 * @fastchannel_init: A common helper used to initialize FC descriptors by
255 * gathering FC descriptions from the SCMI platform server.
256 * @fastchannel_db_ring: A common helper to ring a FC doorbell.
258 struct scmi_proto_helpers_ops {
259 int (*extended_name_get)(const struct scmi_protocol_handle *ph,
260 u8 cmd_id, u32 res_id, u32 *flags, char *name,
262 void *(*iter_response_init)(const struct scmi_protocol_handle *ph,
263 struct scmi_iterator_ops *ops,
264 unsigned int max_resources, u8 msg_id,
265 size_t tx_size, void *priv);
266 int (*iter_response_run)(void *iter);
267 void (*fastchannel_init)(const struct scmi_protocol_handle *ph,
268 u8 describe_id, u32 message_id,
269 u32 valid_size, u32 domain,
270 void __iomem **p_addr,
271 struct scmi_fc_db_info **p_db);
272 void (*fastchannel_db_ring)(struct scmi_fc_db_info *db);
276 * struct scmi_xfer_ops - References to the core SCMI xfer operations.
277 * @version_get: Get this version protocol.
278 * @xfer_get_init: Initialize one struct xfer if any xfer slot is free.
279 * @reset_rx_to_maxsz: Reset rx size to max transport size.
280 * @do_xfer: Do the SCMI transfer.
281 * @do_xfer_with_response: Do the SCMI transfer waiting for a response.
282 * @xfer_put: Free the xfer slot.
284 * Note that all this operations expect a protocol handle as first parameter;
285 * they then internally use it to infer the underlying protocol number: this
286 * way is not possible for a protocol implementation to forge messages for
289 struct scmi_xfer_ops {
290 int (*version_get)(const struct scmi_protocol_handle *ph, u32 *version);
291 int (*xfer_get_init)(const struct scmi_protocol_handle *ph, u8 msg_id,
292 size_t tx_size, size_t rx_size,
293 struct scmi_xfer **p);
294 void (*reset_rx_to_maxsz)(const struct scmi_protocol_handle *ph,
295 struct scmi_xfer *xfer);
296 int (*do_xfer)(const struct scmi_protocol_handle *ph,
297 struct scmi_xfer *xfer);
298 int (*do_xfer_with_response)(const struct scmi_protocol_handle *ph,
299 struct scmi_xfer *xfer);
300 void (*xfer_put)(const struct scmi_protocol_handle *ph,
301 struct scmi_xfer *xfer);
304 typedef int (*scmi_prot_init_ph_fn_t)(const struct scmi_protocol_handle *);
307 * struct scmi_protocol - Protocol descriptor
309 * @owner: Module reference if any.
310 * @instance_init: Mandatory protocol initialization function.
311 * @instance_deinit: Optional protocol de-initialization function.
312 * @ops: Optional reference to the operations provided by the protocol and
313 * exposed in scmi_protocol.h.
314 * @events: An optional reference to the events supported by this protocol.
315 * @supported_version: The highest version currently supported for this
316 * protocol by the agent. Each protocol implementation
317 * in the agent is supposed to downgrade to match the
318 * protocol version supported by the platform.
320 struct scmi_protocol {
322 struct module *owner;
323 const scmi_prot_init_ph_fn_t instance_init;
324 const scmi_prot_init_ph_fn_t instance_deinit;
326 const struct scmi_protocol_events *events;
327 unsigned int supported_version;
330 #define DEFINE_SCMI_PROTOCOL_REGISTER_UNREGISTER(name, proto) \
331 static const struct scmi_protocol *__this_proto = &(proto); \
333 int __init scmi_##name##_register(void) \
335 return scmi_protocol_register(__this_proto); \
338 void __exit scmi_##name##_unregister(void) \
340 scmi_protocol_unregister(__this_proto); \
343 #define DECLARE_SCMI_REGISTER_UNREGISTER(func) \
344 int __init scmi_##func##_register(void); \
345 void __exit scmi_##func##_unregister(void)
346 DECLARE_SCMI_REGISTER_UNREGISTER(base);
347 DECLARE_SCMI_REGISTER_UNREGISTER(clock);
348 DECLARE_SCMI_REGISTER_UNREGISTER(perf);
349 DECLARE_SCMI_REGISTER_UNREGISTER(power);
350 DECLARE_SCMI_REGISTER_UNREGISTER(reset);
351 DECLARE_SCMI_REGISTER_UNREGISTER(sensors);
352 DECLARE_SCMI_REGISTER_UNREGISTER(voltage);
353 DECLARE_SCMI_REGISTER_UNREGISTER(system);
354 DECLARE_SCMI_REGISTER_UNREGISTER(powercap);
356 #endif /* _SCMI_PROTOCOLS_H */