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 enum scmi_common_cmd { 33 PROTOCOL_VERSION = 0x0, 34 PROTOCOL_ATTRIBUTES = 0x1, 35 PROTOCOL_MESSAGE_ATTRIBUTES = 0x2, 36 }; 37 38 /** 39 * struct scmi_msg_resp_prot_version - Response for a message 40 * 41 * @minor_version: Minor version of the ABI that firmware supports 42 * @major_version: Major version of the ABI that firmware supports 43 * 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. 47 * 48 * Response to a generic message with message type SCMI_MSG_VERSION 49 */ 50 struct scmi_msg_resp_prot_version { 51 __le16 minor_version; 52 __le16 major_version; 53 }; 54 55 /** 56 * struct scmi_msg - Message(Tx/Rx) structure 57 * 58 * @buf: Buffer pointer 59 * @len: Length of data in the Buffer 60 */ 61 struct scmi_msg { 62 void *buf; 63 size_t len; 64 }; 65 66 /** 67 * struct scmi_msg_hdr - Message(Tx/Rx) header 68 * 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 74 * token 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 78 */ 79 struct scmi_msg_hdr { 80 u8 id; 81 u8 protocol_id; 82 u8 type; 83 u16 seq; 84 u32 status; 85 bool poll_completion; 86 }; 87 88 /** 89 * struct scmi_xfer - Structure representing a message flow 90 * 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 114 * valid being: 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 * @lock: A spinlock to protect state and busy fields. 119 * @priv: A pointer for transport private usage. 120 */ 121 struct scmi_xfer { 122 int transfer_id; 123 struct scmi_msg_hdr hdr; 124 struct scmi_msg tx; 125 struct scmi_msg rx; 126 struct completion done; 127 struct completion *async_done; 128 bool pending; 129 struct hlist_node node; 130 refcount_t users; 131 #define SCMI_XFER_FREE 0 132 #define SCMI_XFER_BUSY 1 133 atomic_t busy; 134 #define SCMI_XFER_SENT_OK 0 135 #define SCMI_XFER_RESP_OK 1 136 #define SCMI_XFER_DRESP_OK 2 137 int state; 138 /* A lock to protect state and busy fields */ 139 spinlock_t lock; 140 void *priv; 141 }; 142 143 struct scmi_xfer_ops; 144 struct scmi_proto_helpers_ops; 145 146 /** 147 * struct scmi_protocol_handle - Reference to an initialized protocol instance 148 * 149 * @dev: A reference to the associated SCMI instance device (handle->dev). 150 * @xops: A reference to a struct holding refs to the core xfer operations that 151 * can be used by the protocol implementation to generate SCMI messages. 152 * @set_priv: A method to set protocol private data for this instance. 153 * @get_priv: A method to get protocol private data previously set. 154 * 155 * This structure represents a protocol initialized against specific SCMI 156 * instance and it will be used as follows: 157 * - as a parameter fed from the core to the protocol initialization code so 158 * that it can access the core xfer operations to build and generate SCMI 159 * messages exclusively for the specific underlying protocol instance. 160 * - as an opaque handle fed by an SCMI driver user when it tries to access 161 * this protocol through its own protocol operations. 162 * In this case this handle will be returned as an opaque object together 163 * with the related protocol operations when the SCMI driver tries to access 164 * the protocol. 165 */ 166 struct scmi_protocol_handle { 167 struct device *dev; 168 const struct scmi_xfer_ops *xops; 169 const struct scmi_proto_helpers_ops *hops; 170 int (*set_priv)(const struct scmi_protocol_handle *ph, void *priv); 171 void *(*get_priv)(const struct scmi_protocol_handle *ph); 172 }; 173 174 /** 175 * struct scmi_iterator_state - Iterator current state descriptor 176 * @desc_index: Starting index for the current mulit-part request. 177 * @num_returned: Number of returned items in the last multi-part reply. 178 * @num_remaining: Number of remaining items in the multi-part message. 179 * @max_resources: Maximum acceptable number of items, configured by the caller 180 * depending on the underlying resources that it is querying. 181 * @loop_idx: The iterator loop index in the current multi-part reply. 182 * @rx_len: Size in bytes of the currenly processed message; it can be used by 183 * the user of the iterator to verify a reply size. 184 * @priv: Optional pointer to some additional state-related private data setup 185 * by the caller during the iterations. 186 */ 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; 193 size_t rx_len; 194 void *priv; 195 }; 196 197 /** 198 * struct scmi_iterator_ops - Custom iterator operations 199 * @prepare_message: An operation to provide the custom logic to fill in the 200 * SCMI command request pointed by @message. @desc_index is 201 * a reference to the next index to use in the multi-part 202 * request. 203 * @update_state: An operation to provide the custom logic to update the 204 * iterator state from the actual message response. 205 * @process_response: An operation to provide the custom logic needed to process 206 * each chunk of the multi-part message. 207 */ 208 struct scmi_iterator_ops { 209 void (*prepare_message)(void *message, unsigned int desc_index, 210 const void *priv); 211 int (*update_state)(struct scmi_iterator_state *st, 212 const void *response, void *priv); 213 int (*process_response)(const struct scmi_protocol_handle *ph, 214 const void *response, 215 struct scmi_iterator_state *st, void *priv); 216 }; 217 218 struct scmi_fc_db_info { 219 int width; 220 u64 set; 221 u64 mask; 222 void __iomem *addr; 223 }; 224 225 struct scmi_fc_info { 226 void __iomem *set_addr; 227 void __iomem *get_addr; 228 struct scmi_fc_db_info *set_db; 229 }; 230 231 /** 232 * struct scmi_proto_helpers_ops - References to common protocol helpers 233 * @extended_name_get: A common helper function to retrieve extended naming 234 * for the specified resource using the specified command. 235 * Result is returned as a NULL terminated string in the 236 * pre-allocated area pointed to by @name with maximum 237 * capacity of @len bytes. 238 * @iter_response_init: A common helper to initialize a generic iterator to 239 * parse multi-message responses: when run the iterator 240 * will take care to send the initial command request as 241 * specified by @msg_id and @tx_size and then to parse the 242 * multi-part responses using the custom operations 243 * provided in @ops. 244 * @iter_response_run: A common helper to trigger the run of a previously 245 * initialized iterator. 246 * @fastchannel_init: A common helper used to initialize FC descriptors by 247 * gathering FC descriptions from the SCMI platform server. 248 * @fastchannel_db_ring: A common helper to ring a FC doorbell. 249 */ 250 struct scmi_proto_helpers_ops { 251 int (*extended_name_get)(const struct scmi_protocol_handle *ph, 252 u8 cmd_id, u32 res_id, char *name, size_t len); 253 void *(*iter_response_init)(const struct scmi_protocol_handle *ph, 254 struct scmi_iterator_ops *ops, 255 unsigned int max_resources, u8 msg_id, 256 size_t tx_size, void *priv); 257 int (*iter_response_run)(void *iter); 258 void (*fastchannel_init)(const struct scmi_protocol_handle *ph, 259 u8 describe_id, u32 message_id, 260 u32 valid_size, u32 domain, 261 void __iomem **p_addr, 262 struct scmi_fc_db_info **p_db); 263 void (*fastchannel_db_ring)(struct scmi_fc_db_info *db); 264 }; 265 266 /** 267 * struct scmi_xfer_ops - References to the core SCMI xfer operations. 268 * @version_get: Get this version protocol. 269 * @xfer_get_init: Initialize one struct xfer if any xfer slot is free. 270 * @reset_rx_to_maxsz: Reset rx size to max transport size. 271 * @do_xfer: Do the SCMI transfer. 272 * @do_xfer_with_response: Do the SCMI transfer waiting for a response. 273 * @xfer_put: Free the xfer slot. 274 * 275 * Note that all this operations expect a protocol handle as first parameter; 276 * they then internally use it to infer the underlying protocol number: this 277 * way is not possible for a protocol implementation to forge messages for 278 * another protocol. 279 */ 280 struct scmi_xfer_ops { 281 int (*version_get)(const struct scmi_protocol_handle *ph, u32 *version); 282 int (*xfer_get_init)(const struct scmi_protocol_handle *ph, u8 msg_id, 283 size_t tx_size, size_t rx_size, 284 struct scmi_xfer **p); 285 void (*reset_rx_to_maxsz)(const struct scmi_protocol_handle *ph, 286 struct scmi_xfer *xfer); 287 int (*do_xfer)(const struct scmi_protocol_handle *ph, 288 struct scmi_xfer *xfer); 289 int (*do_xfer_with_response)(const struct scmi_protocol_handle *ph, 290 struct scmi_xfer *xfer); 291 void (*xfer_put)(const struct scmi_protocol_handle *ph, 292 struct scmi_xfer *xfer); 293 }; 294 295 typedef int (*scmi_prot_init_ph_fn_t)(const struct scmi_protocol_handle *); 296 297 /** 298 * struct scmi_protocol - Protocol descriptor 299 * @id: Protocol ID. 300 * @owner: Module reference if any. 301 * @instance_init: Mandatory protocol initialization function. 302 * @instance_deinit: Optional protocol de-initialization function. 303 * @ops: Optional reference to the operations provided by the protocol and 304 * exposed in scmi_protocol.h. 305 * @events: An optional reference to the events supported by this protocol. 306 */ 307 struct scmi_protocol { 308 const u8 id; 309 struct module *owner; 310 const scmi_prot_init_ph_fn_t instance_init; 311 const scmi_prot_init_ph_fn_t instance_deinit; 312 const void *ops; 313 const struct scmi_protocol_events *events; 314 }; 315 316 #define DEFINE_SCMI_PROTOCOL_REGISTER_UNREGISTER(name, proto) \ 317 static const struct scmi_protocol *__this_proto = &(proto); \ 318 \ 319 int __init scmi_##name##_register(void) \ 320 { \ 321 return scmi_protocol_register(__this_proto); \ 322 } \ 323 \ 324 void __exit scmi_##name##_unregister(void) \ 325 { \ 326 scmi_protocol_unregister(__this_proto); \ 327 } 328 329 #define DECLARE_SCMI_REGISTER_UNREGISTER(func) \ 330 int __init scmi_##func##_register(void); \ 331 void __exit scmi_##func##_unregister(void) 332 DECLARE_SCMI_REGISTER_UNREGISTER(base); 333 DECLARE_SCMI_REGISTER_UNREGISTER(clock); 334 DECLARE_SCMI_REGISTER_UNREGISTER(perf); 335 DECLARE_SCMI_REGISTER_UNREGISTER(power); 336 DECLARE_SCMI_REGISTER_UNREGISTER(reset); 337 DECLARE_SCMI_REGISTER_UNREGISTER(sensors); 338 DECLARE_SCMI_REGISTER_UNREGISTER(voltage); 339 DECLARE_SCMI_REGISTER_UNREGISTER(system); 340 DECLARE_SCMI_REGISTER_UNREGISTER(powercap); 341 342 #endif /* _SCMI_PROTOCOLS_H */ 343