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 MSG_ID_MASK		GENMASK(7, 0)
31 #define MSG_XTRACT_ID(hdr)	FIELD_GET(MSG_ID_MASK, (hdr))
32 #define MSG_TYPE_MASK		GENMASK(9, 8)
33 #define MSG_XTRACT_TYPE(hdr)	FIELD_GET(MSG_TYPE_MASK, (hdr))
34 #define MSG_TYPE_COMMAND	0
35 #define MSG_TYPE_DELAYED_RESP	2
36 #define MSG_TYPE_NOTIFICATION	3
37 #define MSG_PROTOCOL_ID_MASK	GENMASK(17, 10)
38 #define MSG_XTRACT_PROT_ID(hdr)	FIELD_GET(MSG_PROTOCOL_ID_MASK, (hdr))
39 #define MSG_TOKEN_ID_MASK	GENMASK(27, 18)
40 #define MSG_XTRACT_TOKEN(hdr)	FIELD_GET(MSG_TOKEN_ID_MASK, (hdr))
41 #define MSG_TOKEN_MAX		(MSG_XTRACT_TOKEN(MSG_TOKEN_ID_MASK) + 1)
42 
43 /*
44  * Size of @pending_xfers hashtable included in @scmi_xfers_info; ideally, in
45  * order to minimize space and collisions, this should equal max_msg, i.e. the
46  * maximum number of in-flight messages on a specific platform, but such value
47  * is only available at runtime while kernel hashtables are statically sized:
48  * pick instead as a fixed static size the maximum number of entries that can
49  * fit the whole table into one 4k page.
50  */
51 #define SCMI_PENDING_XFERS_HT_ORDER_SZ		9
52 
53 /**
54  * pack_scmi_header() - packs and returns 32-bit header
55  *
56  * @hdr: pointer to header containing all the information on message id,
57  *	protocol id, sequence id and type.
58  *
59  * Return: 32-bit packed message header to be sent to the platform.
60  */
61 static inline u32 pack_scmi_header(struct scmi_msg_hdr *hdr)
62 {
63 	return FIELD_PREP(MSG_ID_MASK, hdr->id) |
64 		FIELD_PREP(MSG_TYPE_MASK, hdr->type) |
65 		FIELD_PREP(MSG_TOKEN_ID_MASK, hdr->seq) |
66 		FIELD_PREP(MSG_PROTOCOL_ID_MASK, hdr->protocol_id);
67 }
68 
69 /**
70  * unpack_scmi_header() - unpacks and records message and protocol id
71  *
72  * @msg_hdr: 32-bit packed message header sent from the platform
73  * @hdr: pointer to header to fetch message and protocol id.
74  */
75 static inline void unpack_scmi_header(u32 msg_hdr, struct scmi_msg_hdr *hdr)
76 {
77 	hdr->id = MSG_XTRACT_ID(msg_hdr);
78 	hdr->protocol_id = MSG_XTRACT_PROT_ID(msg_hdr);
79 	hdr->type = MSG_XTRACT_TYPE(msg_hdr);
80 }
81 
82 /*
83  * An helper macro to lookup an xfer from the @pending_xfers hashtable
84  * using the message sequence number token as a key.
85  */
86 #define XFER_FIND(__ht, __k)					\
87 ({								\
88 	typeof(__k) k_ = __k;					\
89 	struct scmi_xfer *xfer_ = NULL;				\
90 								\
91 	hash_for_each_possible((__ht), xfer_, node, k_)		\
92 		if (xfer_->hdr.seq == k_)			\
93 			break;					\
94 	xfer_;							\
95 })
96 
97 struct scmi_revision_info *
98 scmi_revision_area_get(const struct scmi_protocol_handle *ph);
99 int scmi_handle_put(const struct scmi_handle *handle);
100 struct scmi_handle *scmi_handle_get(struct device *dev);
101 void scmi_set_handle(struct scmi_device *scmi_dev);
102 void scmi_setup_protocol_implemented(const struct scmi_protocol_handle *ph,
103 				     u8 *prot_imp);
104 
105 int __init scmi_bus_init(void);
106 void __exit scmi_bus_exit(void);
107 
108 const struct scmi_protocol *scmi_protocol_get(int protocol_id);
109 void scmi_protocol_put(int protocol_id);
110 
111 int scmi_protocol_acquire(const struct scmi_handle *handle, u8 protocol_id);
112 void scmi_protocol_release(const struct scmi_handle *handle, u8 protocol_id);
113 
114 /* SCMI Transport */
115 /**
116  * struct scmi_chan_info - Structure representing a SCMI channel information
117  *
118  * @dev: Reference to device in the SCMI hierarchy corresponding to this
119  *	 channel
120  * @handle: Pointer to SCMI entity handle
121  * @no_completion_irq: Flag to indicate that this channel has no completion
122  *		       interrupt mechanism for synchronous commands.
123  *		       This can be dynamically set by transports at run-time
124  *		       inside their provided .chan_setup().
125  * @transport_info: Transport layer related information
126  */
127 struct scmi_chan_info {
128 	struct device *dev;
129 	struct scmi_handle *handle;
130 	bool no_completion_irq;
131 	void *transport_info;
132 };
133 
134 /**
135  * struct scmi_transport_ops - Structure representing a SCMI transport ops
136  *
137  * @link_supplier: Optional callback to add link to a supplier device
138  * @chan_available: Callback to check if channel is available or not
139  * @chan_setup: Callback to allocate and setup a channel
140  * @chan_free: Callback to free a channel
141  * @get_max_msg: Optional callback to provide max_msg dynamically
142  *		 Returns the maximum number of messages for the channel type
143  *		 (tx or rx) that can be pending simultaneously in the system
144  * @send_message: Callback to send a message
145  * @mark_txdone: Callback to mark tx as done
146  * @fetch_response: Callback to fetch response
147  * @fetch_notification: Callback to fetch notification
148  * @clear_channel: Callback to clear a channel
149  * @poll_done: Callback to poll transfer status
150  */
151 struct scmi_transport_ops {
152 	int (*link_supplier)(struct device *dev);
153 	bool (*chan_available)(struct device *dev, int idx);
154 	int (*chan_setup)(struct scmi_chan_info *cinfo, struct device *dev,
155 			  bool tx);
156 	int (*chan_free)(int id, void *p, void *data);
157 	unsigned int (*get_max_msg)(struct scmi_chan_info *base_cinfo);
158 	int (*send_message)(struct scmi_chan_info *cinfo,
159 			    struct scmi_xfer *xfer);
160 	void (*mark_txdone)(struct scmi_chan_info *cinfo, int ret,
161 			    struct scmi_xfer *xfer);
162 	void (*fetch_response)(struct scmi_chan_info *cinfo,
163 			       struct scmi_xfer *xfer);
164 	void (*fetch_notification)(struct scmi_chan_info *cinfo,
165 				   size_t max_len, struct scmi_xfer *xfer);
166 	void (*clear_channel)(struct scmi_chan_info *cinfo);
167 	bool (*poll_done)(struct scmi_chan_info *cinfo, struct scmi_xfer *xfer);
168 };
169 
170 int scmi_protocol_device_request(const struct scmi_device_id *id_table);
171 void scmi_protocol_device_unrequest(const struct scmi_device_id *id_table);
172 struct scmi_device *scmi_child_dev_find(struct device *parent,
173 					int prot_id, const char *name);
174 
175 /**
176  * struct scmi_desc - Description of SoC integration
177  *
178  * @transport_init: An optional function that a transport can provide to
179  *		    initialize some transport-specific setup during SCMI core
180  *		    initialization, so ahead of SCMI core probing.
181  * @transport_exit: An optional function that a transport can provide to
182  *		    de-initialize some transport-specific setup during SCMI core
183  *		    de-initialization, so after SCMI core removal.
184  * @ops: Pointer to the transport specific ops structure
185  * @max_rx_timeout_ms: Timeout for communication with SoC (in Milliseconds)
186  * @max_msg: Maximum number of messages for a channel type (tx or rx) that can
187  *	be pending simultaneously in the system. May be overridden by the
188  *	get_max_msg op.
189  * @max_msg_size: Maximum size of data per message that can be handled.
190  * @force_polling: Flag to force this whole transport to use SCMI core polling
191  *		   mechanism instead of completion interrupts even if available.
192  * @sync_cmds_completed_on_ret: Flag to indicate that the transport assures
193  *				synchronous-command messages are atomically
194  *				completed on .send_message: no need to poll
195  *				actively waiting for a response.
196  *				Used by core internally only when polling is
197  *				selected as a waiting for reply method: i.e.
198  *				if a completion irq was found use that anyway.
199  * @atomic_enabled: Flag to indicate that this transport, which is assured not
200  *		    to sleep anywhere on the TX path, can be used in atomic mode
201  *		    when requested.
202  */
203 struct scmi_desc {
204 	int (*transport_init)(void);
205 	void (*transport_exit)(void);
206 	const struct scmi_transport_ops *ops;
207 	int max_rx_timeout_ms;
208 	int max_msg;
209 	int max_msg_size;
210 	const bool force_polling;
211 	const bool sync_cmds_completed_on_ret;
212 	const bool atomic_enabled;
213 };
214 
215 #ifdef CONFIG_ARM_SCMI_TRANSPORT_MAILBOX
216 extern const struct scmi_desc scmi_mailbox_desc;
217 #endif
218 #ifdef CONFIG_ARM_SCMI_TRANSPORT_SMC
219 extern const struct scmi_desc scmi_smc_desc;
220 #endif
221 #ifdef CONFIG_ARM_SCMI_TRANSPORT_VIRTIO
222 extern const struct scmi_desc scmi_virtio_desc;
223 #endif
224 #ifdef CONFIG_ARM_SCMI_TRANSPORT_OPTEE
225 extern const struct scmi_desc scmi_optee_desc;
226 #endif
227 
228 void scmi_rx_callback(struct scmi_chan_info *cinfo, u32 msg_hdr, void *priv);
229 void scmi_free_channel(struct scmi_chan_info *cinfo, struct idr *idr, int id);
230 
231 /* shmem related declarations */
232 struct scmi_shared_mem;
233 
234 void shmem_tx_prepare(struct scmi_shared_mem __iomem *shmem,
235 		      struct scmi_xfer *xfer);
236 u32 shmem_read_header(struct scmi_shared_mem __iomem *shmem);
237 void shmem_fetch_response(struct scmi_shared_mem __iomem *shmem,
238 			  struct scmi_xfer *xfer);
239 void shmem_fetch_notification(struct scmi_shared_mem __iomem *shmem,
240 			      size_t max_len, struct scmi_xfer *xfer);
241 void shmem_clear_channel(struct scmi_shared_mem __iomem *shmem);
242 bool shmem_poll_done(struct scmi_shared_mem __iomem *shmem,
243 		     struct scmi_xfer *xfer);
244 
245 /* declarations for message passing transports */
246 struct scmi_msg_payld;
247 
248 /* Maximum overhead of message w.r.t. struct scmi_desc.max_msg_size */
249 #define SCMI_MSG_MAX_PROT_OVERHEAD (2 * sizeof(__le32))
250 
251 size_t msg_response_size(struct scmi_xfer *xfer);
252 size_t msg_command_size(struct scmi_xfer *xfer);
253 void msg_tx_prepare(struct scmi_msg_payld *msg, struct scmi_xfer *xfer);
254 u32 msg_read_header(struct scmi_msg_payld *msg);
255 void msg_fetch_response(struct scmi_msg_payld *msg, size_t len,
256 			struct scmi_xfer *xfer);
257 void msg_fetch_notification(struct scmi_msg_payld *msg, size_t len,
258 			    size_t max_len, struct scmi_xfer *xfer);
259 
260 void scmi_notification_instance_data_set(const struct scmi_handle *handle,
261 					 void *priv);
262 void *scmi_notification_instance_data_get(const struct scmi_handle *handle);
263 #endif /* _SCMI_COMMON_H */
264