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 36 enum 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 */ 55 struct 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 */ 66 struct 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 */ 84 struct 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 * or NULL when no delayed response is expected. Protected by 105 * @lock, since the completion is owned by the waiter and can 106 * vanish once the wait times out. 107 * @pending: True for xfers added to @pending_xfers hashtable 108 * @node: An hlist_node reference used to store this xfer, alternatively, on 109 * the free list @free_xfers or in the @pending_xfers hashtable 110 * @users: A refcount to track the active users for this xfer. 111 * This is meant to protect against the possibility that, when a command 112 * transaction times out concurrently with the reception of a valid 113 * response message, the xfer could be finally put on the TX path, and 114 * so vanish, while on the RX path scmi_rx_callback() is still 115 * processing it: in such a case this refcounting will ensure that, even 116 * though the timed-out transaction will anyway cause the command 117 * request to be reported as failed by time-out, the underlying xfer 118 * cannot be discarded and possibly reused until the last one user on 119 * the RX path has released it. 120 * @busy: An atomic flag to ensure exclusive write access to this xfer 121 * @state: The current state of this transfer, with states transitions deemed 122 * valid being: 123 * - SCMI_XFER_SENT_OK -> SCMI_XFER_RESP_OK [ -> SCMI_XFER_DRESP_OK ] 124 * - SCMI_XFER_SENT_OK -> SCMI_XFER_DRESP_OK 125 * (Missing synchronous response is assumed OK and ignored) 126 * @flags: Optional flags associated to this xfer. 127 * @lock: A spinlock to protect state, busy and async_done fields. 128 * @priv: A pointer for transport private usage. 129 */ 130 struct scmi_xfer { 131 int transfer_id; 132 struct scmi_msg_hdr hdr; 133 struct scmi_msg tx; 134 struct scmi_msg rx; 135 struct completion done; 136 struct completion *async_done; 137 bool pending; 138 struct hlist_node node; 139 refcount_t users; 140 #define SCMI_XFER_FREE 0 141 #define SCMI_XFER_BUSY 1 142 atomic_t busy; 143 #define SCMI_XFER_SENT_OK 0 144 #define SCMI_XFER_RESP_OK 1 145 #define SCMI_XFER_DRESP_OK 2 146 int state; 147 #define SCMI_XFER_FLAG_IS_RAW BIT(0) 148 #define SCMI_XFER_IS_RAW(x) ((x)->flags & SCMI_XFER_FLAG_IS_RAW) 149 #define SCMI_XFER_FLAG_CHAN_SET BIT(1) 150 #define SCMI_XFER_IS_CHAN_SET(x) \ 151 ((x)->flags & SCMI_XFER_FLAG_CHAN_SET) 152 int flags; 153 /* A lock to protect state, busy and async_done fields */ 154 spinlock_t lock; 155 void *priv; 156 }; 157 158 struct scmi_xfer_ops; 159 struct scmi_proto_helpers_ops; 160 161 /** 162 * struct scmi_protocol_handle - Reference to an initialized protocol instance 163 * 164 * @dev: A reference to the associated SCMI instance device (handle->dev). 165 * @version: The protocol version currently effectively in use by this 166 * initialized instance of the protocol as determined at the end of 167 * any possibly needed negotiations performed by the core. 168 * @xops: A reference to a struct holding refs to the core xfer operations that 169 * can be used by the protocol implementation to generate SCMI messages. 170 * @set_priv: A method to set protocol private data for this instance. 171 * @get_priv: A method to get protocol private data previously set. 172 * 173 * This structure represents a protocol initialized against specific SCMI 174 * instance and it will be used as follows: 175 * - as a parameter fed from the core to the protocol initialization code so 176 * that it can access the core xfer operations to build and generate SCMI 177 * messages exclusively for the specific underlying protocol instance. 178 * - as an opaque handle fed by an SCMI driver user when it tries to access 179 * this protocol through its own protocol operations. 180 * In this case this handle will be returned as an opaque object together 181 * with the related protocol operations when the SCMI driver tries to access 182 * the protocol. 183 */ 184 struct scmi_protocol_handle { 185 struct device *dev; 186 unsigned int version; 187 const struct scmi_xfer_ops *xops; 188 const struct scmi_proto_helpers_ops *hops; 189 int (*set_priv)(const struct scmi_protocol_handle *ph, void *priv); 190 void *(*get_priv)(const struct scmi_protocol_handle *ph); 191 }; 192 193 /** 194 * struct scmi_iterator_state - Iterator current state descriptor 195 * @desc_index: Starting index for the current multi-part request. 196 * @num_returned: Number of returned items in the last multi-part reply. 197 * @num_remaining: Number of remaining items in the multi-part message. 198 * @max_resources: Maximum acceptable number of items, configured by the caller 199 * depending on the underlying resources that it is querying. 200 * @loop_idx: The iterator loop index in the current multi-part reply. 201 * @rx_len: Size in bytes of the currently processed message; it can be used by 202 * the user of the iterator to verify a reply size. 203 * @priv: Optional pointer to some additional state-related private data setup 204 * by the caller during the iterations. 205 */ 206 struct scmi_iterator_state { 207 unsigned int desc_index; 208 unsigned int num_returned; 209 unsigned int num_remaining; 210 unsigned int max_resources; 211 unsigned int loop_idx; 212 size_t rx_len; 213 void *priv; 214 }; 215 216 /** 217 * struct scmi_iterator_ops - Custom iterator operations 218 * @prepare_message: An operation to provide the custom logic to fill in the 219 * SCMI command request pointed by @message. @desc_index is 220 * a reference to the next index to use in the multi-part 221 * request. 222 * @update_state: An operation to provide the custom logic to update the 223 * iterator state from the actual message response. 224 * @process_response: An operation to provide the custom logic needed to process 225 * each chunk of the multi-part message. 226 */ 227 struct scmi_iterator_ops { 228 void (*prepare_message)(void *message, unsigned int desc_index, 229 const void *priv); 230 int (*update_state)(struct scmi_iterator_state *st, 231 const void *response, void *priv); 232 int (*process_response)(const struct scmi_protocol_handle *ph, 233 const void *response, 234 struct scmi_iterator_state *st, void *priv); 235 }; 236 237 struct scmi_fc_db_info { 238 int width; 239 u64 set; 240 u64 mask; 241 void __iomem *addr; 242 }; 243 244 struct scmi_fc_info { 245 void __iomem *set_addr; 246 void __iomem *get_addr; 247 struct scmi_fc_db_info *set_db; 248 u32 rate_limit; 249 }; 250 251 /** 252 * struct scmi_proto_helpers_ops - References to common protocol helpers 253 * @extended_name_get: A common helper function to retrieve extended naming 254 * for the specified resource using the specified command. 255 * Result is returned as a NULL terminated string in the 256 * pre-allocated area pointed to by @name with maximum 257 * capacity of @len bytes. 258 * @iter_response_init: A common helper to initialize a generic iterator to 259 * parse multi-message responses: when run the iterator 260 * will take care to send the initial command request as 261 * specified by @msg_id and @tx_size and then to parse the 262 * multi-part responses using the custom operations 263 * provided in @ops. 264 * @iter_response_run: A common helper to trigger the run of a previously 265 * initialized iterator. Note that unbound iterators are 266 * automatically cleaned up. 267 * @iter_response_run_bound: A common helper to trigger the run of a previously 268 * initialized iterator, but only within the 269 * specified, optional, @start and @end resource 270 * indexes. Note that these bound-iterators need 271 * explicit cleanup via @iter_response_bound_cleanup. 272 * @iter_response_bound_cleanup: A common helper to finally release the iterator 273 * for bound iterators. 274 * @protocol_msg_check: A common helper to check is a specific protocol message 275 * is supported. 276 * @fastchannel_init: A common helper used to initialize FC descriptors by 277 * gathering FC descriptions from the SCMI platform server. 278 * @fastchannel_db_ring: A common helper to ring a FC doorbell. 279 * @get_max_msg_size: A common helper to get the maximum message size. 280 */ 281 struct scmi_proto_helpers_ops { 282 int (*extended_name_get)(const struct scmi_protocol_handle *ph, 283 u8 cmd_id, u32 res_id, u32 *flags, char *name, 284 size_t len); 285 void *(*iter_response_init)(const struct scmi_protocol_handle *ph, 286 struct scmi_iterator_ops *ops, 287 unsigned int max_resources, u8 msg_id, 288 size_t tx_size, void *priv); 289 int (*iter_response_run)(void *iter); 290 int (*iter_response_run_bound)(void *iter, 291 unsigned int *start, unsigned int *end); 292 void (*iter_response_bound_cleanup)(void *iter); 293 int (*protocol_msg_check)(const struct scmi_protocol_handle *ph, 294 u32 message_id, u32 *attributes); 295 void (*fastchannel_init)(const struct scmi_protocol_handle *ph, 296 u8 describe_id, u32 message_id, 297 u32 valid_size, u32 domain, 298 void __iomem **p_addr, 299 struct scmi_fc_db_info **p_db, 300 u32 *rate_limit); 301 void (*fastchannel_db_ring)(struct scmi_fc_db_info *db); 302 int (*get_max_msg_size)(const struct scmi_protocol_handle *ph); 303 }; 304 305 /** 306 * struct scmi_xfer_ops - References to the core SCMI xfer operations. 307 * @xfer_get_init: Initialize one struct xfer if any xfer slot is free. 308 * @reset_rx_to_maxsz: Reset rx size to max transport size. 309 * @do_xfer: Do the SCMI transfer. 310 * @do_xfer_with_response: Do the SCMI transfer waiting for a response. 311 * @xfer_put: Free the xfer slot. 312 * 313 * Note that all this operations expect a protocol handle as first parameter; 314 * they then internally use it to infer the underlying protocol number: this 315 * way is not possible for a protocol implementation to forge messages for 316 * another protocol. 317 */ 318 struct scmi_xfer_ops { 319 int (*xfer_get_init)(const struct scmi_protocol_handle *ph, u8 msg_id, 320 size_t tx_size, size_t rx_size, 321 struct scmi_xfer **p); 322 void (*reset_rx_to_maxsz)(const struct scmi_protocol_handle *ph, 323 struct scmi_xfer *xfer); 324 int (*do_xfer)(const struct scmi_protocol_handle *ph, 325 struct scmi_xfer *xfer); 326 int (*do_xfer_with_response)(const struct scmi_protocol_handle *ph, 327 struct scmi_xfer *xfer); 328 void (*xfer_put)(const struct scmi_protocol_handle *ph, 329 struct scmi_xfer *xfer); 330 }; 331 332 typedef int (*scmi_prot_init_ph_fn_t)(const struct scmi_protocol_handle *); 333 334 /** 335 * struct scmi_protocol - Protocol descriptor 336 * @id: Protocol ID. 337 * @owner: Module reference if any. 338 * @instance_init: Mandatory protocol initialization function. 339 * @instance_deinit: Optional protocol de-initialization function. 340 * @ops: Optional reference to the operations provided by the protocol and 341 * exposed in scmi_protocol.h. 342 * @events: An optional reference to the events supported by this protocol. 343 * @supported_version: The highest version currently supported for this 344 * protocol by the agent. Each protocol implementation 345 * in the agent is supposed to downgrade to match the 346 * protocol version supported by the platform. 347 * @vendor_id: A firmware vendor string for vendor protocols matching. 348 * Ignored when @id identifies a standard protocol, cannot be NULL 349 * otherwise. 350 * @sub_vendor_id: A firmware sub_vendor string for vendor protocols matching. 351 * Ignored if NULL or when @id identifies a standard protocol. 352 * @impl_ver: A firmware implementation version for vendor protocols matching. 353 * Ignored if zero or if @id identifies a standard protocol. 354 * 355 * Note that vendor protocols matching at load time is performed by attempting 356 * the closest match first against the tuple (vendor, sub_vendor, impl_ver) 357 */ 358 struct scmi_protocol { 359 const u8 id; 360 struct module *owner; 361 const scmi_prot_init_ph_fn_t instance_init; 362 const scmi_prot_init_ph_fn_t instance_deinit; 363 const void *ops; 364 const struct scmi_protocol_events *events; 365 unsigned int supported_version; 366 char *vendor_id; 367 char *sub_vendor_id; 368 u32 impl_ver; 369 }; 370 371 #define DEFINE_SCMI_PROTOCOL_REGISTER_UNREGISTER(name, proto) \ 372 static const struct scmi_protocol *__this_proto = &(proto); \ 373 \ 374 int __init scmi_##name##_register(void) \ 375 { \ 376 return scmi_protocol_register(__this_proto); \ 377 } \ 378 \ 379 void __exit scmi_##name##_unregister(void) \ 380 { \ 381 scmi_protocol_unregister(__this_proto); \ 382 } 383 384 #define DECLARE_SCMI_REGISTER_UNREGISTER(func) \ 385 int __init scmi_##func##_register(void); \ 386 void __exit scmi_##func##_unregister(void) 387 DECLARE_SCMI_REGISTER_UNREGISTER(base); 388 DECLARE_SCMI_REGISTER_UNREGISTER(clock); 389 DECLARE_SCMI_REGISTER_UNREGISTER(perf); 390 DECLARE_SCMI_REGISTER_UNREGISTER(pinctrl); 391 DECLARE_SCMI_REGISTER_UNREGISTER(power); 392 DECLARE_SCMI_REGISTER_UNREGISTER(reset); 393 DECLARE_SCMI_REGISTER_UNREGISTER(sensors); 394 DECLARE_SCMI_REGISTER_UNREGISTER(voltage); 395 DECLARE_SCMI_REGISTER_UNREGISTER(system); 396 DECLARE_SCMI_REGISTER_UNREGISTER(powercap); 397 398 #endif /* _SCMI_PROTOCOLS_H */ 399