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) 2018-2022 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 "protocols.h"
28 #include "notify.h"
29 
30 #define SCMI_MAX_CHANNELS		256
31 
32 #define SCMI_MAX_RESPONSE_TIMEOUT	(2 * MSEC_PER_SEC)
33 
34 enum scmi_error_codes {
35 	SCMI_SUCCESS = 0,	/* Success */
36 	SCMI_ERR_SUPPORT = -1,	/* Not supported */
37 	SCMI_ERR_PARAMS = -2,	/* Invalid Parameters */
38 	SCMI_ERR_ACCESS = -3,	/* Invalid access/permission denied */
39 	SCMI_ERR_ENTRY = -4,	/* Not found */
40 	SCMI_ERR_RANGE = -5,	/* Value out of range */
41 	SCMI_ERR_BUSY = -6,	/* Device busy */
42 	SCMI_ERR_COMMS = -7,	/* Communication Error */
43 	SCMI_ERR_GENERIC = -8,	/* Generic Error */
44 	SCMI_ERR_HARDWARE = -9,	/* Hardware Error */
45 	SCMI_ERR_PROTOCOL = -10,/* Protocol Error */
46 };
47 
48 static const int scmi_linux_errmap[] = {
49 	/* better than switch case as long as return value is continuous */
50 	0,			/* SCMI_SUCCESS */
51 	-EOPNOTSUPP,		/* SCMI_ERR_SUPPORT */
52 	-EINVAL,		/* SCMI_ERR_PARAM */
53 	-EACCES,		/* SCMI_ERR_ACCESS */
54 	-ENOENT,		/* SCMI_ERR_ENTRY */
55 	-ERANGE,		/* SCMI_ERR_RANGE */
56 	-EBUSY,			/* SCMI_ERR_BUSY */
57 	-ECOMM,			/* SCMI_ERR_COMMS */
58 	-EIO,			/* SCMI_ERR_GENERIC */
59 	-EREMOTEIO,		/* SCMI_ERR_HARDWARE */
60 	-EPROTO,		/* SCMI_ERR_PROTOCOL */
61 };
62 
63 static inline int scmi_to_linux_errno(int errno)
64 {
65 	int err_idx = -errno;
66 
67 	if (err_idx >= SCMI_SUCCESS && err_idx < ARRAY_SIZE(scmi_linux_errmap))
68 		return scmi_linux_errmap[err_idx];
69 	return -EIO;
70 }
71 
72 #define MSG_ID_MASK		GENMASK(7, 0)
73 #define MSG_XTRACT_ID(hdr)	FIELD_GET(MSG_ID_MASK, (hdr))
74 #define MSG_TYPE_MASK		GENMASK(9, 8)
75 #define MSG_XTRACT_TYPE(hdr)	FIELD_GET(MSG_TYPE_MASK, (hdr))
76 #define MSG_TYPE_COMMAND	0
77 #define MSG_TYPE_DELAYED_RESP	2
78 #define MSG_TYPE_NOTIFICATION	3
79 #define MSG_PROTOCOL_ID_MASK	GENMASK(17, 10)
80 #define MSG_XTRACT_PROT_ID(hdr)	FIELD_GET(MSG_PROTOCOL_ID_MASK, (hdr))
81 #define MSG_TOKEN_ID_MASK	GENMASK(27, 18)
82 #define MSG_XTRACT_TOKEN(hdr)	FIELD_GET(MSG_TOKEN_ID_MASK, (hdr))
83 #define MSG_TOKEN_MAX		(MSG_XTRACT_TOKEN(MSG_TOKEN_ID_MASK) + 1)
84 
85 /*
86  * Size of @pending_xfers hashtable included in @scmi_xfers_info; ideally, in
87  * order to minimize space and collisions, this should equal max_msg, i.e. the
88  * maximum number of in-flight messages on a specific platform, but such value
89  * is only available at runtime while kernel hashtables are statically sized:
90  * pick instead as a fixed static size the maximum number of entries that can
91  * fit the whole table into one 4k page.
92  */
93 #define SCMI_PENDING_XFERS_HT_ORDER_SZ		9
94 
95 /**
96  * pack_scmi_header() - packs and returns 32-bit header
97  *
98  * @hdr: pointer to header containing all the information on message id,
99  *	protocol id, sequence id and type.
100  *
101  * Return: 32-bit packed message header to be sent to the platform.
102  */
103 static inline u32 pack_scmi_header(struct scmi_msg_hdr *hdr)
104 {
105 	return FIELD_PREP(MSG_ID_MASK, hdr->id) |
106 		FIELD_PREP(MSG_TYPE_MASK, hdr->type) |
107 		FIELD_PREP(MSG_TOKEN_ID_MASK, hdr->seq) |
108 		FIELD_PREP(MSG_PROTOCOL_ID_MASK, hdr->protocol_id);
109 }
110 
111 /**
112  * unpack_scmi_header() - unpacks and records message and protocol id
113  *
114  * @msg_hdr: 32-bit packed message header sent from the platform
115  * @hdr: pointer to header to fetch message and protocol id.
116  */
117 static inline void unpack_scmi_header(u32 msg_hdr, struct scmi_msg_hdr *hdr)
118 {
119 	hdr->id = MSG_XTRACT_ID(msg_hdr);
120 	hdr->protocol_id = MSG_XTRACT_PROT_ID(msg_hdr);
121 	hdr->type = MSG_XTRACT_TYPE(msg_hdr);
122 }
123 
124 /*
125  * An helper macro to lookup an xfer from the @pending_xfers hashtable
126  * using the message sequence number token as a key.
127  */
128 #define XFER_FIND(__ht, __k)					\
129 ({								\
130 	typeof(__k) k_ = __k;					\
131 	struct scmi_xfer *xfer_ = NULL;				\
132 								\
133 	hash_for_each_possible((__ht), xfer_, node, k_)		\
134 		if (xfer_->hdr.seq == k_)			\
135 			break;					\
136 	xfer_;							\
137 })
138 
139 struct scmi_revision_info *
140 scmi_revision_area_get(const struct scmi_protocol_handle *ph);
141 void scmi_setup_protocol_implemented(const struct scmi_protocol_handle *ph,
142 				     u8 *prot_imp);
143 
144 extern struct bus_type scmi_bus_type;
145 
146 #define SCMI_BUS_NOTIFY_DEVICE_REQUEST		0
147 #define SCMI_BUS_NOTIFY_DEVICE_UNREQUEST	1
148 extern struct blocking_notifier_head scmi_requested_devices_nh;
149 
150 struct scmi_device *scmi_device_create(struct device_node *np,
151 				       struct device *parent, int protocol,
152 				       const char *name);
153 void scmi_device_destroy(struct device *parent, int protocol, const char *name);
154 
155 int scmi_protocol_acquire(const struct scmi_handle *handle, u8 protocol_id);
156 void scmi_protocol_release(const struct scmi_handle *handle, u8 protocol_id);
157 
158 /* SCMI Transport */
159 /**
160  * struct scmi_chan_info - Structure representing a SCMI channel information
161  *
162  * @id: An identifier for this channel: this matches the protocol number
163  *      used to initialize this channel
164  * @dev: Reference to device in the SCMI hierarchy corresponding to this
165  *	 channel
166  * @rx_timeout_ms: The configured RX timeout in milliseconds.
167  * @handle: Pointer to SCMI entity handle
168  * @no_completion_irq: Flag to indicate that this channel has no completion
169  *		       interrupt mechanism for synchronous commands.
170  *		       This can be dynamically set by transports at run-time
171  *		       inside their provided .chan_setup().
172  * @transport_info: Transport layer related information
173  */
174 struct scmi_chan_info {
175 	int id;
176 	struct device *dev;
177 	unsigned int rx_timeout_ms;
178 	struct scmi_handle *handle;
179 	bool no_completion_irq;
180 	void *transport_info;
181 };
182 
183 /**
184  * struct scmi_transport_ops - Structure representing a SCMI transport ops
185  *
186  * @link_supplier: Optional callback to add link to a supplier device
187  * @chan_available: Callback to check if channel is available or not
188  * @chan_setup: Callback to allocate and setup a channel
189  * @chan_free: Callback to free a channel
190  * @get_max_msg: Optional callback to provide max_msg dynamically
191  *		 Returns the maximum number of messages for the channel type
192  *		 (tx or rx) that can be pending simultaneously in the system
193  * @send_message: Callback to send a message
194  * @mark_txdone: Callback to mark tx as done
195  * @fetch_response: Callback to fetch response
196  * @fetch_notification: Callback to fetch notification
197  * @clear_channel: Callback to clear a channel
198  * @poll_done: Callback to poll transfer status
199  */
200 struct scmi_transport_ops {
201 	int (*link_supplier)(struct device *dev);
202 	bool (*chan_available)(struct device_node *of_node, int idx);
203 	int (*chan_setup)(struct scmi_chan_info *cinfo, struct device *dev,
204 			  bool tx);
205 	int (*chan_free)(int id, void *p, void *data);
206 	unsigned int (*get_max_msg)(struct scmi_chan_info *base_cinfo);
207 	int (*send_message)(struct scmi_chan_info *cinfo,
208 			    struct scmi_xfer *xfer);
209 	void (*mark_txdone)(struct scmi_chan_info *cinfo, int ret,
210 			    struct scmi_xfer *xfer);
211 	void (*fetch_response)(struct scmi_chan_info *cinfo,
212 			       struct scmi_xfer *xfer);
213 	void (*fetch_notification)(struct scmi_chan_info *cinfo,
214 				   size_t max_len, struct scmi_xfer *xfer);
215 	void (*clear_channel)(struct scmi_chan_info *cinfo);
216 	bool (*poll_done)(struct scmi_chan_info *cinfo, struct scmi_xfer *xfer);
217 };
218 
219 /**
220  * struct scmi_desc - Description of SoC integration
221  *
222  * @transport_init: An optional function that a transport can provide to
223  *		    initialize some transport-specific setup during SCMI core
224  *		    initialization, so ahead of SCMI core probing.
225  * @transport_exit: An optional function that a transport can provide to
226  *		    de-initialize some transport-specific setup during SCMI core
227  *		    de-initialization, so after SCMI core removal.
228  * @ops: Pointer to the transport specific ops structure
229  * @max_rx_timeout_ms: Timeout for communication with SoC (in Milliseconds)
230  * @max_msg: Maximum number of messages for a channel type (tx or rx) that can
231  *	be pending simultaneously in the system. May be overridden by the
232  *	get_max_msg op.
233  * @max_msg_size: Maximum size of data per message that can be handled.
234  * @force_polling: Flag to force this whole transport to use SCMI core polling
235  *		   mechanism instead of completion interrupts even if available.
236  * @sync_cmds_completed_on_ret: Flag to indicate that the transport assures
237  *				synchronous-command messages are atomically
238  *				completed on .send_message: no need to poll
239  *				actively waiting for a response.
240  *				Used by core internally only when polling is
241  *				selected as a waiting for reply method: i.e.
242  *				if a completion irq was found use that anyway.
243  * @atomic_enabled: Flag to indicate that this transport, which is assured not
244  *		    to sleep anywhere on the TX path, can be used in atomic mode
245  *		    when requested.
246  */
247 struct scmi_desc {
248 	int (*transport_init)(void);
249 	void (*transport_exit)(void);
250 	const struct scmi_transport_ops *ops;
251 	int max_rx_timeout_ms;
252 	int max_msg;
253 	int max_msg_size;
254 	const bool force_polling;
255 	const bool sync_cmds_completed_on_ret;
256 	const bool atomic_enabled;
257 };
258 
259 static inline bool is_polling_required(struct scmi_chan_info *cinfo,
260 				       const struct scmi_desc *desc)
261 {
262 	return cinfo->no_completion_irq || desc->force_polling;
263 }
264 
265 static inline bool is_transport_polling_capable(const struct scmi_desc *desc)
266 {
267 	return desc->ops->poll_done || desc->sync_cmds_completed_on_ret;
268 }
269 
270 static inline bool is_polling_enabled(struct scmi_chan_info *cinfo,
271 				      const struct scmi_desc *desc)
272 {
273 	return is_polling_required(cinfo, desc) &&
274 		is_transport_polling_capable(desc);
275 }
276 
277 void scmi_xfer_raw_put(const struct scmi_handle *handle,
278 		       struct scmi_xfer *xfer);
279 struct scmi_xfer *scmi_xfer_raw_get(const struct scmi_handle *handle);
280 struct scmi_chan_info *
281 scmi_xfer_raw_channel_get(const struct scmi_handle *handle, u8 protocol_id);
282 
283 int scmi_xfer_raw_inflight_register(const struct scmi_handle *handle,
284 				    struct scmi_xfer *xfer);
285 
286 int scmi_xfer_raw_wait_for_message_response(struct scmi_chan_info *cinfo,
287 					    struct scmi_xfer *xfer,
288 					    unsigned int timeout_ms);
289 #ifdef CONFIG_ARM_SCMI_TRANSPORT_MAILBOX
290 extern const struct scmi_desc scmi_mailbox_desc;
291 #endif
292 #ifdef CONFIG_ARM_SCMI_TRANSPORT_SMC
293 extern const struct scmi_desc scmi_smc_desc;
294 #endif
295 #ifdef CONFIG_ARM_SCMI_TRANSPORT_VIRTIO
296 extern const struct scmi_desc scmi_virtio_desc;
297 #endif
298 #ifdef CONFIG_ARM_SCMI_TRANSPORT_OPTEE
299 extern const struct scmi_desc scmi_optee_desc;
300 #endif
301 
302 void scmi_rx_callback(struct scmi_chan_info *cinfo, u32 msg_hdr, void *priv);
303 
304 /* shmem related declarations */
305 struct scmi_shared_mem;
306 
307 void shmem_tx_prepare(struct scmi_shared_mem __iomem *shmem,
308 		      struct scmi_xfer *xfer, struct scmi_chan_info *cinfo);
309 u32 shmem_read_header(struct scmi_shared_mem __iomem *shmem);
310 void shmem_fetch_response(struct scmi_shared_mem __iomem *shmem,
311 			  struct scmi_xfer *xfer);
312 void shmem_fetch_notification(struct scmi_shared_mem __iomem *shmem,
313 			      size_t max_len, struct scmi_xfer *xfer);
314 void shmem_clear_channel(struct scmi_shared_mem __iomem *shmem);
315 bool shmem_poll_done(struct scmi_shared_mem __iomem *shmem,
316 		     struct scmi_xfer *xfer);
317 
318 /* declarations for message passing transports */
319 struct scmi_msg_payld;
320 
321 /* Maximum overhead of message w.r.t. struct scmi_desc.max_msg_size */
322 #define SCMI_MSG_MAX_PROT_OVERHEAD (2 * sizeof(__le32))
323 
324 size_t msg_response_size(struct scmi_xfer *xfer);
325 size_t msg_command_size(struct scmi_xfer *xfer);
326 void msg_tx_prepare(struct scmi_msg_payld *msg, struct scmi_xfer *xfer);
327 u32 msg_read_header(struct scmi_msg_payld *msg);
328 void msg_fetch_response(struct scmi_msg_payld *msg, size_t len,
329 			struct scmi_xfer *xfer);
330 void msg_fetch_notification(struct scmi_msg_payld *msg, size_t len,
331 			    size_t max_len, struct scmi_xfer *xfer);
332 
333 void scmi_notification_instance_data_set(const struct scmi_handle *handle,
334 					 void *priv);
335 void *scmi_notification_instance_data_get(const struct scmi_handle *handle);
336 #endif /* _SCMI_COMMON_H */
337