1 /* SPDX-License-Identifier: GPL-2.0 */
2 /*
3  * System Control and Management Interface (SCMI) Message Protocol
4  * driver common header file containing some definitions, structures
5  * and function prototypes used in all the different SCMI protocols.
6  *
7  * Copyright (C) 2018-2021 ARM Ltd.
8  */
9 #ifndef _SCMI_COMMON_H
10 #define _SCMI_COMMON_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 #include "notify.h"
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 #define MAX_PROTOCOLS_IMP	16
34 #define MAX_OPPS		16
35 
36 enum scmi_common_cmd {
37 	PROTOCOL_VERSION = 0x0,
38 	PROTOCOL_ATTRIBUTES = 0x1,
39 	PROTOCOL_MESSAGE_ATTRIBUTES = 0x2,
40 };
41 
42 /**
43  * struct scmi_msg_resp_prot_version - Response for a message
44  *
45  * @minor_version: Minor version of the ABI that firmware supports
46  * @major_version: Major version of the ABI that firmware supports
47  *
48  * In general, ABI version changes follow the rule that minor version increments
49  * are backward compatible. Major revision changes in ABI may not be
50  * backward compatible.
51  *
52  * Response to a generic message with message type SCMI_MSG_VERSION
53  */
54 struct scmi_msg_resp_prot_version {
55 	__le16 minor_version;
56 	__le16 major_version;
57 };
58 
59 #define MSG_ID_MASK		GENMASK(7, 0)
60 #define MSG_XTRACT_ID(hdr)	FIELD_GET(MSG_ID_MASK, (hdr))
61 #define MSG_TYPE_MASK		GENMASK(9, 8)
62 #define MSG_XTRACT_TYPE(hdr)	FIELD_GET(MSG_TYPE_MASK, (hdr))
63 #define MSG_TYPE_COMMAND	0
64 #define MSG_TYPE_DELAYED_RESP	2
65 #define MSG_TYPE_NOTIFICATION	3
66 #define MSG_PROTOCOL_ID_MASK	GENMASK(17, 10)
67 #define MSG_XTRACT_PROT_ID(hdr)	FIELD_GET(MSG_PROTOCOL_ID_MASK, (hdr))
68 #define MSG_TOKEN_ID_MASK	GENMASK(27, 18)
69 #define MSG_XTRACT_TOKEN(hdr)	FIELD_GET(MSG_TOKEN_ID_MASK, (hdr))
70 #define MSG_TOKEN_MAX		(MSG_XTRACT_TOKEN(MSG_TOKEN_ID_MASK) + 1)
71 
72 /*
73  * Size of @pending_xfers hashtable included in @scmi_xfers_info; ideally, in
74  * order to minimize space and collisions, this should equal max_msg, i.e. the
75  * maximum number of in-flight messages on a specific platform, but such value
76  * is only available at runtime while kernel hashtables are statically sized:
77  * pick instead as a fixed static size the maximum number of entries that can
78  * fit the whole table into one 4k page.
79  */
80 #define SCMI_PENDING_XFERS_HT_ORDER_SZ		9
81 
82 /**
83  * struct scmi_msg_hdr - Message(Tx/Rx) header
84  *
85  * @id: The identifier of the message being sent
86  * @protocol_id: The identifier of the protocol used to send @id message
87  * @type: The SCMI type for this message
88  * @seq: The token to identify the message. When a message returns, the
89  *	platform returns the whole message header unmodified including the
90  *	token
91  * @status: Status of the transfer once it's complete
92  * @poll_completion: Indicate if the transfer needs to be polled for
93  *	completion or interrupt mode is used
94  */
95 struct scmi_msg_hdr {
96 	u8 id;
97 	u8 protocol_id;
98 	u8 type;
99 	u16 seq;
100 	u32 status;
101 	bool poll_completion;
102 };
103 
104 /**
105  * pack_scmi_header() - packs and returns 32-bit header
106  *
107  * @hdr: pointer to header containing all the information on message id,
108  *	protocol id, sequence id and type.
109  *
110  * Return: 32-bit packed message header to be sent to the platform.
111  */
pack_scmi_header(struct scmi_msg_hdr * hdr)112 static inline u32 pack_scmi_header(struct scmi_msg_hdr *hdr)
113 {
114 	return FIELD_PREP(MSG_ID_MASK, hdr->id) |
115 		FIELD_PREP(MSG_TYPE_MASK, hdr->type) |
116 		FIELD_PREP(MSG_TOKEN_ID_MASK, hdr->seq) |
117 		FIELD_PREP(MSG_PROTOCOL_ID_MASK, hdr->protocol_id);
118 }
119 
120 /**
121  * unpack_scmi_header() - unpacks and records message and protocol id
122  *
123  * @msg_hdr: 32-bit packed message header sent from the platform
124  * @hdr: pointer to header to fetch message and protocol id.
125  */
unpack_scmi_header(u32 msg_hdr,struct scmi_msg_hdr * hdr)126 static inline void unpack_scmi_header(u32 msg_hdr, struct scmi_msg_hdr *hdr)
127 {
128 	hdr->id = MSG_XTRACT_ID(msg_hdr);
129 	hdr->protocol_id = MSG_XTRACT_PROT_ID(msg_hdr);
130 	hdr->type = MSG_XTRACT_TYPE(msg_hdr);
131 }
132 
133 /**
134  * struct scmi_msg - Message(Tx/Rx) structure
135  *
136  * @buf: Buffer pointer
137  * @len: Length of data in the Buffer
138  */
139 struct scmi_msg {
140 	void *buf;
141 	size_t len;
142 };
143 
144 /**
145  * struct scmi_xfer - Structure representing a message flow
146  *
147  * @transfer_id: Unique ID for debug & profiling purpose
148  * @hdr: Transmit message header
149  * @tx: Transmit message
150  * @rx: Receive message, the buffer should be pre-allocated to store
151  *	message. If request-ACK protocol is used, we can reuse the same
152  *	buffer for the rx path as we use for the tx path.
153  * @done: command message transmit completion event
154  * @async_done: pointer to delayed response message received event completion
155  * @pending: True for xfers added to @pending_xfers hashtable
156  * @node: An hlist_node reference used to store this xfer, alternatively, on
157  *	  the free list @free_xfers or in the @pending_xfers hashtable
158  * @users: A refcount to track the active users for this xfer.
159  *	   This is meant to protect against the possibility that, when a command
160  *	   transaction times out concurrently with the reception of a valid
161  *	   response message, the xfer could be finally put on the TX path, and
162  *	   so vanish, while on the RX path scmi_rx_callback() is still
163  *	   processing it: in such a case this refcounting will ensure that, even
164  *	   though the timed-out transaction will anyway cause the command
165  *	   request to be reported as failed by time-out, the underlying xfer
166  *	   cannot be discarded and possibly reused until the last one user on
167  *	   the RX path has released it.
168  * @busy: An atomic flag to ensure exclusive write access to this xfer
169  * @state: The current state of this transfer, with states transitions deemed
170  *	   valid being:
171  *	    - SCMI_XFER_SENT_OK -> SCMI_XFER_RESP_OK [ -> SCMI_XFER_DRESP_OK ]
172  *	    - SCMI_XFER_SENT_OK -> SCMI_XFER_DRESP_OK
173  *	      (Missing synchronous response is assumed OK and ignored)
174  * @lock: A spinlock to protect state and busy fields.
175  * @priv: A pointer for transport private usage.
176  */
177 struct scmi_xfer {
178 	int transfer_id;
179 	struct scmi_msg_hdr hdr;
180 	struct scmi_msg tx;
181 	struct scmi_msg rx;
182 	struct completion done;
183 	struct completion *async_done;
184 	bool pending;
185 	struct hlist_node node;
186 	refcount_t users;
187 #define SCMI_XFER_FREE		0
188 #define SCMI_XFER_BUSY		1
189 	atomic_t busy;
190 #define SCMI_XFER_SENT_OK	0
191 #define SCMI_XFER_RESP_OK	1
192 #define SCMI_XFER_DRESP_OK	2
193 	int state;
194 	/* A lock to protect state and busy fields */
195 	spinlock_t lock;
196 	void *priv;
197 };
198 
199 /*
200  * An helper macro to lookup an xfer from the @pending_xfers hashtable
201  * using the message sequence number token as a key.
202  */
203 #define XFER_FIND(__ht, __k)					\
204 ({								\
205 	typeof(__k) k_ = __k;					\
206 	struct scmi_xfer *xfer_ = NULL;				\
207 								\
208 	hash_for_each_possible((__ht), xfer_, node, k_)		\
209 		if (xfer_->hdr.seq == k_)			\
210 			break;					\
211 	xfer_;							\
212 })
213 
214 struct scmi_xfer_ops;
215 
216 /**
217  * struct scmi_protocol_handle  - Reference to an initialized protocol instance
218  *
219  * @dev: A reference to the associated SCMI instance device (handle->dev).
220  * @xops: A reference to a struct holding refs to the core xfer operations that
221  *	  can be used by the protocol implementation to generate SCMI messages.
222  * @set_priv: A method to set protocol private data for this instance.
223  * @get_priv: A method to get protocol private data previously set.
224  *
225  * This structure represents a protocol initialized against specific SCMI
226  * instance and it will be used as follows:
227  * - as a parameter fed from the core to the protocol initialization code so
228  *   that it can access the core xfer operations to build and generate SCMI
229  *   messages exclusively for the specific underlying protocol instance.
230  * - as an opaque handle fed by an SCMI driver user when it tries to access
231  *   this protocol through its own protocol operations.
232  *   In this case this handle will be returned as an opaque object together
233  *   with the related protocol operations when the SCMI driver tries to access
234  *   the protocol.
235  */
236 struct scmi_protocol_handle {
237 	struct device *dev;
238 	const struct scmi_xfer_ops *xops;
239 	int (*set_priv)(const struct scmi_protocol_handle *ph, void *priv);
240 	void *(*get_priv)(const struct scmi_protocol_handle *ph);
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 struct scmi_revision_info *
273 scmi_revision_area_get(const struct scmi_protocol_handle *ph);
274 int scmi_handle_put(const struct scmi_handle *handle);
275 struct scmi_handle *scmi_handle_get(struct device *dev);
276 void scmi_set_handle(struct scmi_device *scmi_dev);
277 void scmi_setup_protocol_implemented(const struct scmi_protocol_handle *ph,
278 				     u8 *prot_imp);
279 
280 typedef int (*scmi_prot_init_ph_fn_t)(const struct scmi_protocol_handle *);
281 
282 /**
283  * struct scmi_protocol  - Protocol descriptor
284  * @id: Protocol ID.
285  * @owner: Module reference if any.
286  * @instance_init: Mandatory protocol initialization function.
287  * @instance_deinit: Optional protocol de-initialization function.
288  * @ops: Optional reference to the operations provided by the protocol and
289  *	 exposed in scmi_protocol.h.
290  * @events: An optional reference to the events supported by this protocol.
291  */
292 struct scmi_protocol {
293 	const u8				id;
294 	struct module				*owner;
295 	const scmi_prot_init_ph_fn_t		instance_init;
296 	const scmi_prot_init_ph_fn_t		instance_deinit;
297 	const void				*ops;
298 	const struct scmi_protocol_events	*events;
299 };
300 
301 int __init scmi_bus_init(void);
302 void __exit scmi_bus_exit(void);
303 
304 #define DECLARE_SCMI_REGISTER_UNREGISTER(func)		\
305 	int __init scmi_##func##_register(void);	\
306 	void __exit scmi_##func##_unregister(void)
307 DECLARE_SCMI_REGISTER_UNREGISTER(base);
308 DECLARE_SCMI_REGISTER_UNREGISTER(clock);
309 DECLARE_SCMI_REGISTER_UNREGISTER(perf);
310 DECLARE_SCMI_REGISTER_UNREGISTER(power);
311 DECLARE_SCMI_REGISTER_UNREGISTER(reset);
312 DECLARE_SCMI_REGISTER_UNREGISTER(sensors);
313 DECLARE_SCMI_REGISTER_UNREGISTER(voltage);
314 DECLARE_SCMI_REGISTER_UNREGISTER(system);
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 const struct scmi_protocol *scmi_protocol_get(int protocol_id);
330 void scmi_protocol_put(int protocol_id);
331 
332 int scmi_protocol_acquire(const struct scmi_handle *handle, u8 protocol_id);
333 void scmi_protocol_release(const struct scmi_handle *handle, u8 protocol_id);
334 
335 /* SCMI Transport */
336 /**
337  * struct scmi_chan_info - Structure representing a SCMI channel information
338  *
339  * @dev: Reference to device in the SCMI hierarchy corresponding to this
340  *	 channel
341  * @handle: Pointer to SCMI entity handle
342  * @transport_info: Transport layer related information
343  */
344 struct scmi_chan_info {
345 	struct device *dev;
346 	struct scmi_handle *handle;
347 	void *transport_info;
348 };
349 
350 /**
351  * struct scmi_transport_ops - Structure representing a SCMI transport ops
352  *
353  * @link_supplier: Optional callback to add link to a supplier device
354  * @chan_available: Callback to check if channel is available or not
355  * @chan_setup: Callback to allocate and setup a channel
356  * @chan_free: Callback to free a channel
357  * @get_max_msg: Optional callback to provide max_msg dynamically
358  *		 Returns the maximum number of messages for the channel type
359  *		 (tx or rx) that can be pending simultaneously in the system
360  * @send_message: Callback to send a message
361  * @mark_txdone: Callback to mark tx as done
362  * @fetch_response: Callback to fetch response
363  * @fetch_notification: Callback to fetch notification
364  * @clear_channel: Callback to clear a channel
365  * @poll_done: Callback to poll transfer status
366  */
367 struct scmi_transport_ops {
368 	int (*link_supplier)(struct device *dev);
369 	bool (*chan_available)(struct device *dev, int idx);
370 	int (*chan_setup)(struct scmi_chan_info *cinfo, struct device *dev,
371 			  bool tx);
372 	int (*chan_free)(int id, void *p, void *data);
373 	unsigned int (*get_max_msg)(struct scmi_chan_info *base_cinfo);
374 	int (*send_message)(struct scmi_chan_info *cinfo,
375 			    struct scmi_xfer *xfer);
376 	void (*mark_txdone)(struct scmi_chan_info *cinfo, int ret);
377 	void (*fetch_response)(struct scmi_chan_info *cinfo,
378 			       struct scmi_xfer *xfer);
379 	void (*fetch_notification)(struct scmi_chan_info *cinfo,
380 				   size_t max_len, struct scmi_xfer *xfer);
381 	void (*clear_channel)(struct scmi_chan_info *cinfo);
382 	bool (*poll_done)(struct scmi_chan_info *cinfo, struct scmi_xfer *xfer);
383 };
384 
385 int scmi_protocol_device_request(const struct scmi_device_id *id_table);
386 void scmi_protocol_device_unrequest(const struct scmi_device_id *id_table);
387 struct scmi_device *scmi_child_dev_find(struct device *parent,
388 					int prot_id, const char *name);
389 
390 /**
391  * struct scmi_desc - Description of SoC integration
392  *
393  * @transport_init: An optional function that a transport can provide to
394  *		    initialize some transport-specific setup during SCMI core
395  *		    initialization, so ahead of SCMI core probing.
396  * @transport_exit: An optional function that a transport can provide to
397  *		    de-initialize some transport-specific setup during SCMI core
398  *		    de-initialization, so after SCMI core removal.
399  * @ops: Pointer to the transport specific ops structure
400  * @max_rx_timeout_ms: Timeout for communication with SoC (in Milliseconds)
401  * @max_msg: Maximum number of messages for a channel type (tx or rx) that can
402  *	be pending simultaneously in the system. May be overridden by the
403  *	get_max_msg op.
404  * @max_msg_size: Maximum size of data per message that can be handled.
405  */
406 struct scmi_desc {
407 	int (*transport_init)(void);
408 	void (*transport_exit)(void);
409 	const struct scmi_transport_ops *ops;
410 	int max_rx_timeout_ms;
411 	int max_msg;
412 	int max_msg_size;
413 };
414 
415 #ifdef CONFIG_ARM_SCMI_TRANSPORT_MAILBOX
416 extern const struct scmi_desc scmi_mailbox_desc;
417 #endif
418 #ifdef CONFIG_ARM_SCMI_TRANSPORT_SMC
419 extern const struct scmi_desc scmi_smc_desc;
420 #endif
421 #ifdef CONFIG_ARM_SCMI_TRANSPORT_VIRTIO
422 extern const struct scmi_desc scmi_virtio_desc;
423 #endif
424 
425 void scmi_rx_callback(struct scmi_chan_info *cinfo, u32 msg_hdr, void *priv);
426 void scmi_free_channel(struct scmi_chan_info *cinfo, struct idr *idr, int id);
427 
428 /* shmem related declarations */
429 struct scmi_shared_mem;
430 
431 void shmem_tx_prepare(struct scmi_shared_mem __iomem *shmem,
432 		      struct scmi_xfer *xfer);
433 u32 shmem_read_header(struct scmi_shared_mem __iomem *shmem);
434 void shmem_fetch_response(struct scmi_shared_mem __iomem *shmem,
435 			  struct scmi_xfer *xfer);
436 void shmem_fetch_notification(struct scmi_shared_mem __iomem *shmem,
437 			      size_t max_len, struct scmi_xfer *xfer);
438 void shmem_clear_channel(struct scmi_shared_mem __iomem *shmem);
439 bool shmem_poll_done(struct scmi_shared_mem __iomem *shmem,
440 		     struct scmi_xfer *xfer);
441 
442 /* declarations for message passing transports */
443 struct scmi_msg_payld;
444 
445 /* Maximum overhead of message w.r.t. struct scmi_desc.max_msg_size */
446 #define SCMI_MSG_MAX_PROT_OVERHEAD (2 * sizeof(__le32))
447 
448 size_t msg_response_size(struct scmi_xfer *xfer);
449 size_t msg_command_size(struct scmi_xfer *xfer);
450 void msg_tx_prepare(struct scmi_msg_payld *msg, struct scmi_xfer *xfer);
451 u32 msg_read_header(struct scmi_msg_payld *msg);
452 void msg_fetch_response(struct scmi_msg_payld *msg, size_t len,
453 			struct scmi_xfer *xfer);
454 void msg_fetch_notification(struct scmi_msg_payld *msg, size_t len,
455 			    size_t max_len, struct scmi_xfer *xfer);
456 
457 void scmi_notification_instance_data_set(const struct scmi_handle *handle,
458 					 void *priv);
459 void *scmi_notification_instance_data_get(const struct scmi_handle *handle);
460 #endif /* _SCMI_COMMON_H */
461