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