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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 <linux/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
32#define SCMI_PROTOCOL_VENDOR_BASE 0x80
33
34#define MSG_SUPPORTS_FASTCHANNEL(x) ((x) & BIT(0))
35
36enum scmi_common_cmd {
37 PROTOCOL_VERSION = 0x0,
38 PROTOCOL_ATTRIBUTES = 0x1,
39 PROTOCOL_MESSAGE_ATTRIBUTES = 0x2,
40 NEGOTIATE_PROTOCOL_VERSION = 0x10,
41};
42
43/**
44 * struct scmi_msg_resp_prot_version - Response for a message
45 *
46 * @minor_version: Minor version of the ABI that firmware supports
47 * @major_version: Major version of the ABI that firmware supports
48 *
49 * In general, ABI version changes follow the rule that minor version increments
50 * are backward compatible. Major revision changes in ABI may not be
51 * backward compatible.
52 *
53 * Response to a generic message with message type SCMI_MSG_VERSION
54 */
55struct scmi_msg_resp_prot_version {
56 __le16 minor_version;
57 __le16 major_version;
58};
59
60/**
61 * struct scmi_msg - Message(Tx/Rx) structure
62 *
63 * @buf: Buffer pointer
64 * @len: Length of data in the Buffer
65 */
66struct scmi_msg {
67 void *buf;
68 size_t len;
69};
70
71/**
72 * struct scmi_msg_hdr - Message(Tx/Rx) header
73 *
74 * @id: The identifier of the message being sent
75 * @protocol_id: The identifier of the protocol used to send @id message
76 * @type: The SCMI type for this message
77 * @seq: The token to identify the message. When a message returns, the
78 * platform returns the whole message header unmodified including the
79 * token
80 * @status: Status of the transfer once it's complete
81 * @poll_completion: Indicate if the transfer needs to be polled for
82 * completion or interrupt mode is used
83 */
84struct scmi_msg_hdr {
85 u8 id;
86 u8 protocol_id;
87 u8 type;
88 u16 seq;
89 u32 status;
90 bool poll_completion;
91};
92
93/**
94 * struct scmi_xfer - Structure representing a message flow
95 *
96 * @transfer_id: Unique ID for debug & profiling purpose
97 * @hdr: Transmit message header
98 * @tx: Transmit message
99 * @rx: Receive message, the buffer should be pre-allocated to store
100 * message. If request-ACK protocol is used, we can reuse the same
101 * buffer for the rx path as we use for the tx path.
102 * @done: command message transmit completion event
103 * @async_done: pointer to delayed response message received event completion
104 * @pending: True for xfers added to @pending_xfers hashtable
105 * @node: An hlist_node reference used to store this xfer, alternatively, on
106 * the free list @free_xfers or in the @pending_xfers hashtable
107 * @users: A refcount to track the active users for this xfer.
108 * This is meant to protect against the possibility that, when a command
109 * transaction times out concurrently with the reception of a valid
110 * response message, the xfer could be finally put on the TX path, and
111 * so vanish, while on the RX path scmi_rx_callback() is still
112 * processing it: in such a case this refcounting will ensure that, even
113 * though the timed-out transaction will anyway cause the command
114 * request to be reported as failed by time-out, the underlying xfer
115 * cannot be discarded and possibly reused until the last one user on
116 * the RX path has released it.
117 * @busy: An atomic flag to ensure exclusive write access to this xfer
118 * @state: The current state of this transfer, with states transitions deemed
119 * valid being:
120 * - SCMI_XFER_SENT_OK -> SCMI_XFER_RESP_OK [ -> SCMI_XFER_DRESP_OK ]
121 * - SCMI_XFER_SENT_OK -> SCMI_XFER_DRESP_OK
122 * (Missing synchronous response is assumed OK and ignored)
123 * @flags: Optional flags associated to this xfer.
124 * @lock: A spinlock to protect state and busy fields.
125 * @priv: A pointer for transport private usage.
126 */
127struct scmi_xfer {
128 int transfer_id;
129 struct scmi_msg_hdr hdr;
130 struct scmi_msg tx;
131 struct scmi_msg rx;
132 struct completion done;
133 struct completion *async_done;
134 bool pending;
135 struct hlist_node node;
136 refcount_t users;
137#define SCMI_XFER_FREE 0
138#define SCMI_XFER_BUSY 1
139 atomic_t busy;
140#define SCMI_XFER_SENT_OK 0
141#define SCMI_XFER_RESP_OK 1
142#define SCMI_XFER_DRESP_OK 2
143 int state;
144#define SCMI_XFER_FLAG_IS_RAW BIT(0)
145#define SCMI_XFER_IS_RAW(x) ((x)->flags & SCMI_XFER_FLAG_IS_RAW)
146#define SCMI_XFER_FLAG_CHAN_SET BIT(1)
147#define SCMI_XFER_IS_CHAN_SET(x) \
148 ((x)->flags & SCMI_XFER_FLAG_CHAN_SET)
149 int flags;
150 /* A lock to protect state and busy fields */
151 spinlock_t lock;
152 void *priv;
153};
154
155struct scmi_xfer_ops;
156struct scmi_proto_helpers_ops;
157
158/**
159 * struct scmi_protocol_handle - Reference to an initialized protocol instance
160 *
161 * @dev: A reference to the associated SCMI instance device (handle->dev).
162 * @version: The protocol version currently effectively in use by this
163 * initialized instance of the protocol as determined at the end of
164 * any possibly needed negotiations performed by the core.
165 * @xops: A reference to a struct holding refs to the core xfer operations that
166 * can be used by the protocol implementation to generate SCMI messages.
167 * @set_priv: A method to set protocol private data for this instance.
168 * @get_priv: A method to get protocol private data previously set.
169 *
170 * This structure represents a protocol initialized against specific SCMI
171 * instance and it will be used as follows:
172 * - as a parameter fed from the core to the protocol initialization code so
173 * that it can access the core xfer operations to build and generate SCMI
174 * messages exclusively for the specific underlying protocol instance.
175 * - as an opaque handle fed by an SCMI driver user when it tries to access
176 * this protocol through its own protocol operations.
177 * In this case this handle will be returned as an opaque object together
178 * with the related protocol operations when the SCMI driver tries to access
179 * the protocol.
180 */
181struct scmi_protocol_handle {
182 struct device *dev;
183 unsigned int version;
184 const struct scmi_xfer_ops *xops;
185 const struct scmi_proto_helpers_ops *hops;
186 int (*set_priv)(const struct scmi_protocol_handle *ph, void *priv);
187 void *(*get_priv)(const struct scmi_protocol_handle *ph);
188};
189
190/**
191 * struct scmi_iterator_state - Iterator current state descriptor
192 * @desc_index: Starting index for the current multi-part request.
193 * @num_returned: Number of returned items in the last multi-part reply.
194 * @num_remaining: Number of remaining items in the multi-part message.
195 * @max_resources: Maximum acceptable number of items, configured by the caller
196 * depending on the underlying resources that it is querying.
197 * @loop_idx: The iterator loop index in the current multi-part reply.
198 * @rx_len: Size in bytes of the currently processed message; it can be used by
199 * the user of the iterator to verify a reply size.
200 * @priv: Optional pointer to some additional state-related private data setup
201 * by the caller during the iterations.
202 */
203struct scmi_iterator_state {
204 unsigned int desc_index;
205 unsigned int num_returned;
206 unsigned int num_remaining;
207 unsigned int max_resources;
208 unsigned int loop_idx;
209 size_t rx_len;
210 void *priv;
211};
212
213/**
214 * struct scmi_iterator_ops - Custom iterator operations
215 * @prepare_message: An operation to provide the custom logic to fill in the
216 * SCMI command request pointed by @message. @desc_index is
217 * a reference to the next index to use in the multi-part
218 * request.
219 * @update_state: An operation to provide the custom logic to update the
220 * iterator state from the actual message response.
221 * @process_response: An operation to provide the custom logic needed to process
222 * each chunk of the multi-part message.
223 */
224struct scmi_iterator_ops {
225 void (*prepare_message)(void *message, unsigned int desc_index,
226 const void *priv);
227 int (*update_state)(struct scmi_iterator_state *st,
228 const void *response, void *priv);
229 int (*process_response)(const struct scmi_protocol_handle *ph,
230 const void *response,
231 struct scmi_iterator_state *st, void *priv);
232};
233
234struct scmi_fc_db_info {
235 int width;
236 u64 set;
237 u64 mask;
238 void __iomem *addr;
239};
240
241struct scmi_fc_info {
242 void __iomem *set_addr;
243 void __iomem *get_addr;
244 struct scmi_fc_db_info *set_db;
245 u32 rate_limit;
246};
247
248/**
249 * struct scmi_proto_helpers_ops - References to common protocol helpers
250 * @extended_name_get: A common helper function to retrieve extended naming
251 * for the specified resource using the specified command.
252 * Result is returned as a NULL terminated string in the
253 * pre-allocated area pointed to by @name with maximum
254 * capacity of @len bytes.
255 * @iter_response_init: A common helper to initialize a generic iterator to
256 * parse multi-message responses: when run the iterator
257 * will take care to send the initial command request as
258 * specified by @msg_id and @tx_size and then to parse the
259 * multi-part responses using the custom operations
260 * provided in @ops.
261 * @iter_response_run: A common helper to trigger the run of a previously
262 * initialized iterator.
263 * @protocol_msg_check: A common helper to check is a specific protocol message
264 * is supported.
265 * @fastchannel_init: A common helper used to initialize FC descriptors by
266 * gathering FC descriptions from the SCMI platform server.
267 * @fastchannel_db_ring: A common helper to ring a FC doorbell.
268 * @get_max_msg_size: A common helper to get the maximum message size.
269 */
270struct scmi_proto_helpers_ops {
271 int (*extended_name_get)(const struct scmi_protocol_handle *ph,
272 u8 cmd_id, u32 res_id, u32 *flags, char *name,
273 size_t len);
274 void *(*iter_response_init)(const struct scmi_protocol_handle *ph,
275 struct scmi_iterator_ops *ops,
276 unsigned int max_resources, u8 msg_id,
277 size_t tx_size, void *priv);
278 int (*iter_response_run)(void *iter);
279 int (*protocol_msg_check)(const struct scmi_protocol_handle *ph,
280 u32 message_id, u32 *attributes);
281 void (*fastchannel_init)(const struct scmi_protocol_handle *ph,
282 u8 describe_id, u32 message_id,
283 u32 valid_size, u32 domain,
284 void __iomem **p_addr,
285 struct scmi_fc_db_info **p_db,
286 u32 *rate_limit);
287 void (*fastchannel_db_ring)(struct scmi_fc_db_info *db);
288 int (*get_max_msg_size)(const struct scmi_protocol_handle *ph);
289};
290
291/**
292 * struct scmi_xfer_ops - References to the core SCMI xfer operations.
293 * @xfer_get_init: Initialize one struct xfer if any xfer slot is free.
294 * @reset_rx_to_maxsz: Reset rx size to max transport size.
295 * @do_xfer: Do the SCMI transfer.
296 * @do_xfer_with_response: Do the SCMI transfer waiting for a response.
297 * @xfer_put: Free the xfer slot.
298 *
299 * Note that all this operations expect a protocol handle as first parameter;
300 * they then internally use it to infer the underlying protocol number: this
301 * way is not possible for a protocol implementation to forge messages for
302 * another protocol.
303 */
304struct scmi_xfer_ops {
305 int (*xfer_get_init)(const struct scmi_protocol_handle *ph, u8 msg_id,
306 size_t tx_size, size_t rx_size,
307 struct scmi_xfer **p);
308 void (*reset_rx_to_maxsz)(const struct scmi_protocol_handle *ph,
309 struct scmi_xfer *xfer);
310 int (*do_xfer)(const struct scmi_protocol_handle *ph,
311 struct scmi_xfer *xfer);
312 int (*do_xfer_with_response)(const struct scmi_protocol_handle *ph,
313 struct scmi_xfer *xfer);
314 void (*xfer_put)(const struct scmi_protocol_handle *ph,
315 struct scmi_xfer *xfer);
316};
317
318typedef int (*scmi_prot_init_ph_fn_t)(const struct scmi_protocol_handle *);
319
320/**
321 * struct scmi_protocol - Protocol descriptor
322 * @id: Protocol ID.
323 * @owner: Module reference if any.
324 * @instance_init: Mandatory protocol initialization function.
325 * @instance_deinit: Optional protocol de-initialization function.
326 * @ops: Optional reference to the operations provided by the protocol and
327 * exposed in scmi_protocol.h.
328 * @events: An optional reference to the events supported by this protocol.
329 * @supported_version: The highest version currently supported for this
330 * protocol by the agent. Each protocol implementation
331 * in the agent is supposed to downgrade to match the
332 * protocol version supported by the platform.
333 * @vendor_id: A firmware vendor string for vendor protocols matching.
334 * Ignored when @id identifies a standard protocol, cannot be NULL
335 * otherwise.
336 * @sub_vendor_id: A firmware sub_vendor string for vendor protocols matching.
337 * Ignored if NULL or when @id identifies a standard protocol.
338 * @impl_ver: A firmware implementation version for vendor protocols matching.
339 * Ignored if zero or if @id identifies a standard protocol.
340 *
341 * Note that vendor protocols matching at load time is performed by attempting
342 * the closest match first against the tuple (vendor, sub_vendor, impl_ver)
343 */
344struct scmi_protocol {
345 const u8 id;
346 struct module *owner;
347 const scmi_prot_init_ph_fn_t instance_init;
348 const scmi_prot_init_ph_fn_t instance_deinit;
349 const void *ops;
350 const struct scmi_protocol_events *events;
351 unsigned int supported_version;
352 char *vendor_id;
353 char *sub_vendor_id;
354 u32 impl_ver;
355};
356
357#define DEFINE_SCMI_PROTOCOL_REGISTER_UNREGISTER(name, proto) \
358static const struct scmi_protocol *__this_proto = &(proto); \
359 \
360int __init scmi_##name##_register(void) \
361{ \
362 return scmi_protocol_register(__this_proto); \
363} \
364 \
365void __exit scmi_##name##_unregister(void) \
366{ \
367 scmi_protocol_unregister(__this_proto); \
368}
369
370#define DECLARE_SCMI_REGISTER_UNREGISTER(func) \
371 int __init scmi_##func##_register(void); \
372 void __exit scmi_##func##_unregister(void)
373DECLARE_SCMI_REGISTER_UNREGISTER(base);
374DECLARE_SCMI_REGISTER_UNREGISTER(clock);
375DECLARE_SCMI_REGISTER_UNREGISTER(perf);
376DECLARE_SCMI_REGISTER_UNREGISTER(pinctrl);
377DECLARE_SCMI_REGISTER_UNREGISTER(power);
378DECLARE_SCMI_REGISTER_UNREGISTER(reset);
379DECLARE_SCMI_REGISTER_UNREGISTER(sensors);
380DECLARE_SCMI_REGISTER_UNREGISTER(voltage);
381DECLARE_SCMI_REGISTER_UNREGISTER(system);
382DECLARE_SCMI_REGISTER_UNREGISTER(powercap);
383
384#endif /* _SCMI_PROTOCOLS_H */