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