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}; 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 */ 50struct 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 */ 61struct 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 */ 79struct 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 * @flags: Optional flags associated to this xfer. 119 * @lock: A spinlock to protect state and busy fields. 120 * @priv: A pointer for transport private usage. 121 */ 122struct scmi_xfer { 123 int transfer_id; 124 struct scmi_msg_hdr hdr; 125 struct scmi_msg tx; 126 struct scmi_msg rx; 127 struct completion done; 128 struct completion *async_done; 129 bool pending; 130 struct hlist_node node; 131 refcount_t users; 132#define SCMI_XFER_FREE 0 133#define SCMI_XFER_BUSY 1 134 atomic_t busy; 135#define SCMI_XFER_SENT_OK 0 136#define SCMI_XFER_RESP_OK 1 137#define SCMI_XFER_DRESP_OK 2 138 int state; 139#define SCMI_XFER_FLAG_IS_RAW BIT(0) 140#define SCMI_XFER_IS_RAW(x) ((x)->flags & SCMI_XFER_FLAG_IS_RAW) 141#define SCMI_XFER_FLAG_CHAN_SET BIT(1) 142#define SCMI_XFER_IS_CHAN_SET(x) \ 143 ((x)->flags & SCMI_XFER_FLAG_CHAN_SET) 144 int flags; 145 /* A lock to protect state and busy fields */ 146 spinlock_t lock; 147 void *priv; 148}; 149 150struct scmi_xfer_ops; 151struct scmi_proto_helpers_ops; 152 153/** 154 * struct scmi_protocol_handle - Reference to an initialized protocol instance 155 * 156 * @dev: A reference to the associated SCMI instance device (handle->dev). 157 * @xops: A reference to a struct holding refs to the core xfer operations that 158 * can be used by the protocol implementation to generate SCMI messages. 159 * @set_priv: A method to set protocol private data for this instance. 160 * @get_priv: A method to get protocol private data previously set. 161 * 162 * This structure represents a protocol initialized against specific SCMI 163 * instance and it will be used as follows: 164 * - as a parameter fed from the core to the protocol initialization code so 165 * that it can access the core xfer operations to build and generate SCMI 166 * messages exclusively for the specific underlying protocol instance. 167 * - as an opaque handle fed by an SCMI driver user when it tries to access 168 * this protocol through its own protocol operations. 169 * In this case this handle will be returned as an opaque object together 170 * with the related protocol operations when the SCMI driver tries to access 171 * the protocol. 172 */ 173struct scmi_protocol_handle { 174 struct device *dev; 175 const struct scmi_xfer_ops *xops; 176 const struct scmi_proto_helpers_ops *hops; 177 int (*set_priv)(const struct scmi_protocol_handle *ph, void *priv); 178 void *(*get_priv)(const struct scmi_protocol_handle *ph); 179}; 180 181/** 182 * struct scmi_iterator_state - Iterator current state descriptor 183 * @desc_index: Starting index for the current mulit-part request. 184 * @num_returned: Number of returned items in the last multi-part reply. 185 * @num_remaining: Number of remaining items in the multi-part message. 186 * @max_resources: Maximum acceptable number of items, configured by the caller 187 * depending on the underlying resources that it is querying. 188 * @loop_idx: The iterator loop index in the current multi-part reply. 189 * @rx_len: Size in bytes of the currenly processed message; it can be used by 190 * the user of the iterator to verify a reply size. 191 * @priv: Optional pointer to some additional state-related private data setup 192 * by the caller during the iterations. 193 */ 194struct scmi_iterator_state { 195 unsigned int desc_index; 196 unsigned int num_returned; 197 unsigned int num_remaining; 198 unsigned int max_resources; 199 unsigned int loop_idx; 200 size_t rx_len; 201 void *priv; 202}; 203 204/** 205 * struct scmi_iterator_ops - Custom iterator operations 206 * @prepare_message: An operation to provide the custom logic to fill in the 207 * SCMI command request pointed by @message. @desc_index is 208 * a reference to the next index to use in the multi-part 209 * request. 210 * @update_state: An operation to provide the custom logic to update the 211 * iterator state from the actual message response. 212 * @process_response: An operation to provide the custom logic needed to process 213 * each chunk of the multi-part message. 214 */ 215struct scmi_iterator_ops { 216 void (*prepare_message)(void *message, unsigned int desc_index, 217 const void *priv); 218 int (*update_state)(struct scmi_iterator_state *st, 219 const void *response, void *priv); 220 int (*process_response)(const struct scmi_protocol_handle *ph, 221 const void *response, 222 struct scmi_iterator_state *st, void *priv); 223}; 224 225struct scmi_fc_db_info { 226 int width; 227 u64 set; 228 u64 mask; 229 void __iomem *addr; 230}; 231 232struct scmi_fc_info { 233 void __iomem *set_addr; 234 void __iomem *get_addr; 235 struct scmi_fc_db_info *set_db; 236}; 237 238/** 239 * struct scmi_proto_helpers_ops - References to common protocol helpers 240 * @extended_name_get: A common helper function to retrieve extended naming 241 * for the specified resource using the specified command. 242 * Result is returned as a NULL terminated string in the 243 * pre-allocated area pointed to by @name with maximum 244 * capacity of @len bytes. 245 * @iter_response_init: A common helper to initialize a generic iterator to 246 * parse multi-message responses: when run the iterator 247 * will take care to send the initial command request as 248 * specified by @msg_id and @tx_size and then to parse the 249 * multi-part responses using the custom operations 250 * provided in @ops. 251 * @iter_response_run: A common helper to trigger the run of a previously 252 * initialized iterator. 253 * @fastchannel_init: A common helper used to initialize FC descriptors by 254 * gathering FC descriptions from the SCMI platform server. 255 * @fastchannel_db_ring: A common helper to ring a FC doorbell. 256 */ 257struct scmi_proto_helpers_ops { 258 int (*extended_name_get)(const struct scmi_protocol_handle *ph, 259 u8 cmd_id, u32 res_id, char *name, size_t len); 260 void *(*iter_response_init)(const struct scmi_protocol_handle *ph, 261 struct scmi_iterator_ops *ops, 262 unsigned int max_resources, u8 msg_id, 263 size_t tx_size, void *priv); 264 int (*iter_response_run)(void *iter); 265 void (*fastchannel_init)(const struct scmi_protocol_handle *ph, 266 u8 describe_id, u32 message_id, 267 u32 valid_size, u32 domain, 268 void __iomem **p_addr, 269 struct scmi_fc_db_info **p_db); 270 void (*fastchannel_db_ring)(struct scmi_fc_db_info *db); 271}; 272 273/** 274 * struct scmi_xfer_ops - References to the core SCMI xfer operations. 275 * @version_get: Get this version protocol. 276 * @xfer_get_init: Initialize one struct xfer if any xfer slot is free. 277 * @reset_rx_to_maxsz: Reset rx size to max transport size. 278 * @do_xfer: Do the SCMI transfer. 279 * @do_xfer_with_response: Do the SCMI transfer waiting for a response. 280 * @xfer_put: Free the xfer slot. 281 * 282 * Note that all this operations expect a protocol handle as first parameter; 283 * they then internally use it to infer the underlying protocol number: this 284 * way is not possible for a protocol implementation to forge messages for 285 * another protocol. 286 */ 287struct scmi_xfer_ops { 288 int (*version_get)(const struct scmi_protocol_handle *ph, u32 *version); 289 int (*xfer_get_init)(const struct scmi_protocol_handle *ph, u8 msg_id, 290 size_t tx_size, size_t rx_size, 291 struct scmi_xfer **p); 292 void (*reset_rx_to_maxsz)(const struct scmi_protocol_handle *ph, 293 struct scmi_xfer *xfer); 294 int (*do_xfer)(const struct scmi_protocol_handle *ph, 295 struct scmi_xfer *xfer); 296 int (*do_xfer_with_response)(const struct scmi_protocol_handle *ph, 297 struct scmi_xfer *xfer); 298 void (*xfer_put)(const struct scmi_protocol_handle *ph, 299 struct scmi_xfer *xfer); 300}; 301 302typedef int (*scmi_prot_init_ph_fn_t)(const struct scmi_protocol_handle *); 303 304/** 305 * struct scmi_protocol - Protocol descriptor 306 * @id: Protocol ID. 307 * @owner: Module reference if any. 308 * @instance_init: Mandatory protocol initialization function. 309 * @instance_deinit: Optional protocol de-initialization function. 310 * @ops: Optional reference to the operations provided by the protocol and 311 * exposed in scmi_protocol.h. 312 * @events: An optional reference to the events supported by this protocol. 313 */ 314struct scmi_protocol { 315 const u8 id; 316 struct module *owner; 317 const scmi_prot_init_ph_fn_t instance_init; 318 const scmi_prot_init_ph_fn_t instance_deinit; 319 const void *ops; 320 const struct scmi_protocol_events *events; 321}; 322 323#define DEFINE_SCMI_PROTOCOL_REGISTER_UNREGISTER(name, proto) \ 324static const struct scmi_protocol *__this_proto = &(proto); \ 325 \ 326int __init scmi_##name##_register(void) \ 327{ \ 328 return scmi_protocol_register(__this_proto); \ 329} \ 330 \ 331void __exit scmi_##name##_unregister(void) \ 332{ \ 333 scmi_protocol_unregister(__this_proto); \ 334} 335 336#define DECLARE_SCMI_REGISTER_UNREGISTER(func) \ 337 int __init scmi_##func##_register(void); \ 338 void __exit scmi_##func##_unregister(void) 339DECLARE_SCMI_REGISTER_UNREGISTER(base); 340DECLARE_SCMI_REGISTER_UNREGISTER(clock); 341DECLARE_SCMI_REGISTER_UNREGISTER(perf); 342DECLARE_SCMI_REGISTER_UNREGISTER(power); 343DECLARE_SCMI_REGISTER_UNREGISTER(reset); 344DECLARE_SCMI_REGISTER_UNREGISTER(sensors); 345DECLARE_SCMI_REGISTER_UNREGISTER(voltage); 346DECLARE_SCMI_REGISTER_UNREGISTER(system); 347DECLARE_SCMI_REGISTER_UNREGISTER(powercap); 348 349#endif /* _SCMI_PROTOCOLS_H */ 350