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 SCMI_SHORT_NAME_MAX_SIZE 16 28 29 #define PROTOCOL_REV_MINOR_MASK GENMASK(15, 0) 30 #define PROTOCOL_REV_MAJOR_MASK GENMASK(31, 16) 31 #define PROTOCOL_REV_MAJOR(x) ((u16)(FIELD_GET(PROTOCOL_REV_MAJOR_MASK, (x)))) 32 #define PROTOCOL_REV_MINOR(x) ((u16)(FIELD_GET(PROTOCOL_REV_MINOR_MASK, (x)))) 33 34 enum scmi_common_cmd { 35 PROTOCOL_VERSION = 0x0, 36 PROTOCOL_ATTRIBUTES = 0x1, 37 PROTOCOL_MESSAGE_ATTRIBUTES = 0x2, 38 }; 39 40 /** 41 * struct scmi_msg_resp_prot_version - Response for a message 42 * 43 * @minor_version: Minor version of the ABI that firmware supports 44 * @major_version: Major version of the ABI that firmware supports 45 * 46 * In general, ABI version changes follow the rule that minor version increments 47 * are backward compatible. Major revision changes in ABI may not be 48 * backward compatible. 49 * 50 * Response to a generic message with message type SCMI_MSG_VERSION 51 */ 52 struct scmi_msg_resp_prot_version { 53 __le16 minor_version; 54 __le16 major_version; 55 }; 56 57 /** 58 * struct scmi_msg - Message(Tx/Rx) structure 59 * 60 * @buf: Buffer pointer 61 * @len: Length of data in the Buffer 62 */ 63 struct scmi_msg { 64 void *buf; 65 size_t len; 66 }; 67 68 /** 69 * struct scmi_msg_hdr - Message(Tx/Rx) header 70 * 71 * @id: The identifier of the message being sent 72 * @protocol_id: The identifier of the protocol used to send @id message 73 * @type: The SCMI type for this message 74 * @seq: The token to identify the message. When a message returns, the 75 * platform returns the whole message header unmodified including the 76 * token 77 * @status: Status of the transfer once it's complete 78 * @poll_completion: Indicate if the transfer needs to be polled for 79 * completion or interrupt mode is used 80 */ 81 struct scmi_msg_hdr { 82 u8 id; 83 u8 protocol_id; 84 u8 type; 85 u16 seq; 86 u32 status; 87 bool poll_completion; 88 }; 89 90 /** 91 * struct scmi_xfer - Structure representing a message flow 92 * 93 * @transfer_id: Unique ID for debug & profiling purpose 94 * @hdr: Transmit message header 95 * @tx: Transmit message 96 * @rx: Receive message, the buffer should be pre-allocated to store 97 * message. If request-ACK protocol is used, we can reuse the same 98 * buffer for the rx path as we use for the tx path. 99 * @done: command message transmit completion event 100 * @async_done: pointer to delayed response message received event completion 101 * @pending: True for xfers added to @pending_xfers hashtable 102 * @node: An hlist_node reference used to store this xfer, alternatively, on 103 * the free list @free_xfers or in the @pending_xfers hashtable 104 * @users: A refcount to track the active users for this xfer. 105 * This is meant to protect against the possibility that, when a command 106 * transaction times out concurrently with the reception of a valid 107 * response message, the xfer could be finally put on the TX path, and 108 * so vanish, while on the RX path scmi_rx_callback() is still 109 * processing it: in such a case this refcounting will ensure that, even 110 * though the timed-out transaction will anyway cause the command 111 * request to be reported as failed by time-out, the underlying xfer 112 * cannot be discarded and possibly reused until the last one user on 113 * the RX path has released it. 114 * @busy: An atomic flag to ensure exclusive write access to this xfer 115 * @state: The current state of this transfer, with states transitions deemed 116 * valid being: 117 * - SCMI_XFER_SENT_OK -> SCMI_XFER_RESP_OK [ -> SCMI_XFER_DRESP_OK ] 118 * - SCMI_XFER_SENT_OK -> SCMI_XFER_DRESP_OK 119 * (Missing synchronous response is assumed OK and ignored) 120 * @lock: A spinlock to protect state and busy fields. 121 * @priv: A pointer for transport private usage. 122 */ 123 struct 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 /* A lock to protect state and busy fields */ 141 spinlock_t lock; 142 void *priv; 143 }; 144 145 struct scmi_xfer_ops; 146 struct scmi_proto_helpers_ops; 147 148 /** 149 * struct scmi_protocol_handle - Reference to an initialized protocol instance 150 * 151 * @dev: A reference to the associated SCMI instance device (handle->dev). 152 * @xops: A reference to a struct holding refs to the core xfer operations that 153 * can be used by the protocol implementation to generate SCMI messages. 154 * @set_priv: A method to set protocol private data for this instance. 155 * @get_priv: A method to get protocol private data previously set. 156 * 157 * This structure represents a protocol initialized against specific SCMI 158 * instance and it will be used as follows: 159 * - as a parameter fed from the core to the protocol initialization code so 160 * that it can access the core xfer operations to build and generate SCMI 161 * messages exclusively for the specific underlying protocol instance. 162 * - as an opaque handle fed by an SCMI driver user when it tries to access 163 * this protocol through its own protocol operations. 164 * In this case this handle will be returned as an opaque object together 165 * with the related protocol operations when the SCMI driver tries to access 166 * the protocol. 167 */ 168 struct scmi_protocol_handle { 169 struct device *dev; 170 const struct scmi_xfer_ops *xops; 171 const struct scmi_proto_helpers_ops *hops; 172 int (*set_priv)(const struct scmi_protocol_handle *ph, void *priv); 173 void *(*get_priv)(const struct scmi_protocol_handle *ph); 174 }; 175 176 /** 177 * struct scmi_iterator_state - Iterator current state descriptor 178 * @desc_index: Starting index for the current mulit-part request. 179 * @num_returned: Number of returned items in the last multi-part reply. 180 * @num_remaining: Number of remaining items in the multi-part message. 181 * @max_resources: Maximum acceptable number of items, configured by the caller 182 * depending on the underlying resources that it is querying. 183 * @loop_idx: The iterator loop index in the current multi-part reply. 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 void *priv; 194 }; 195 196 /** 197 * struct scmi_iterator_ops - Custom iterator operations 198 * @prepare_message: An operation to provide the custom logic to fill in the 199 * SCMI command request pointed by @message. @desc_index is 200 * a reference to the next index to use in the multi-part 201 * request. 202 * @update_state: An operation to provide the custom logic to update the 203 * iterator state from the actual message response. 204 * @process_response: An operation to provide the custom logic needed to process 205 * each chunk of the multi-part message. 206 */ 207 struct scmi_iterator_ops { 208 void (*prepare_message)(void *message, unsigned int desc_index, 209 const void *priv); 210 int (*update_state)(struct scmi_iterator_state *st, 211 const void *response, void *priv); 212 int (*process_response)(const struct scmi_protocol_handle *ph, 213 const void *response, 214 struct scmi_iterator_state *st, void *priv); 215 }; 216 217 /** 218 * struct scmi_proto_helpers_ops - References to common protocol helpers 219 * @extended_name_get: A common helper function to retrieve extended naming 220 * for the specified resource using the specified command. 221 * Result is returned as a NULL terminated string in the 222 * pre-allocated area pointed to by @name with maximum 223 * capacity of @len bytes. 224 * @iter_response_init: A common helper to initialize a generic iterator to 225 * parse multi-message responses: when run the iterator 226 * will take care to send the initial command request as 227 * specified by @msg_id and @tx_size and then to parse the 228 * multi-part responses using the custom operations 229 * provided in @ops. 230 * @iter_response_run: A common helper to trigger the run of a previously 231 * initialized iterator. 232 */ 233 struct scmi_proto_helpers_ops { 234 int (*extended_name_get)(const struct scmi_protocol_handle *ph, 235 u8 cmd_id, u32 res_id, char *name, size_t len); 236 void *(*iter_response_init)(const struct scmi_protocol_handle *ph, 237 struct scmi_iterator_ops *ops, 238 unsigned int max_resources, u8 msg_id, 239 size_t tx_size, void *priv); 240 int (*iter_response_run)(void *iter); 241 }; 242 243 /** 244 * struct scmi_xfer_ops - References to the core SCMI xfer operations. 245 * @version_get: Get this version protocol. 246 * @xfer_get_init: Initialize one struct xfer if any xfer slot is free. 247 * @reset_rx_to_maxsz: Reset rx size to max transport size. 248 * @do_xfer: Do the SCMI transfer. 249 * @do_xfer_with_response: Do the SCMI transfer waiting for a response. 250 * @xfer_put: Free the xfer slot. 251 * 252 * Note that all this operations expect a protocol handle as first parameter; 253 * they then internally use it to infer the underlying protocol number: this 254 * way is not possible for a protocol implementation to forge messages for 255 * another protocol. 256 */ 257 struct scmi_xfer_ops { 258 int (*version_get)(const struct scmi_protocol_handle *ph, u32 *version); 259 int (*xfer_get_init)(const struct scmi_protocol_handle *ph, u8 msg_id, 260 size_t tx_size, size_t rx_size, 261 struct scmi_xfer **p); 262 void (*reset_rx_to_maxsz)(const struct scmi_protocol_handle *ph, 263 struct scmi_xfer *xfer); 264 int (*do_xfer)(const struct scmi_protocol_handle *ph, 265 struct scmi_xfer *xfer); 266 int (*do_xfer_with_response)(const struct scmi_protocol_handle *ph, 267 struct scmi_xfer *xfer); 268 void (*xfer_put)(const struct scmi_protocol_handle *ph, 269 struct scmi_xfer *xfer); 270 }; 271 272 typedef int (*scmi_prot_init_ph_fn_t)(const struct scmi_protocol_handle *); 273 274 /** 275 * struct scmi_protocol - Protocol descriptor 276 * @id: Protocol ID. 277 * @owner: Module reference if any. 278 * @instance_init: Mandatory protocol initialization function. 279 * @instance_deinit: Optional protocol de-initialization function. 280 * @ops: Optional reference to the operations provided by the protocol and 281 * exposed in scmi_protocol.h. 282 * @events: An optional reference to the events supported by this protocol. 283 */ 284 struct scmi_protocol { 285 const u8 id; 286 struct module *owner; 287 const scmi_prot_init_ph_fn_t instance_init; 288 const scmi_prot_init_ph_fn_t instance_deinit; 289 const void *ops; 290 const struct scmi_protocol_events *events; 291 }; 292 293 #define DEFINE_SCMI_PROTOCOL_REGISTER_UNREGISTER(name, proto) \ 294 static const struct scmi_protocol *__this_proto = &(proto); \ 295 \ 296 int __init scmi_##name##_register(void) \ 297 { \ 298 return scmi_protocol_register(__this_proto); \ 299 } \ 300 \ 301 void __exit scmi_##name##_unregister(void) \ 302 { \ 303 scmi_protocol_unregister(__this_proto); \ 304 } 305 306 #define DECLARE_SCMI_REGISTER_UNREGISTER(func) \ 307 int __init scmi_##func##_register(void); \ 308 void __exit scmi_##func##_unregister(void) 309 DECLARE_SCMI_REGISTER_UNREGISTER(base); 310 DECLARE_SCMI_REGISTER_UNREGISTER(clock); 311 DECLARE_SCMI_REGISTER_UNREGISTER(perf); 312 DECLARE_SCMI_REGISTER_UNREGISTER(power); 313 DECLARE_SCMI_REGISTER_UNREGISTER(reset); 314 DECLARE_SCMI_REGISTER_UNREGISTER(sensors); 315 DECLARE_SCMI_REGISTER_UNREGISTER(voltage); 316 DECLARE_SCMI_REGISTER_UNREGISTER(system); 317 318 #endif /* _SCMI_PROTOCOLS_H */ 319