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 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/scmi_protocol.h>
18 #include <linux/types.h>
19 
20 #include <asm/unaligned.h>
21 
22 #define PROTOCOL_REV_MINOR_MASK	GENMASK(15, 0)
23 #define PROTOCOL_REV_MAJOR_MASK	GENMASK(31, 16)
24 #define PROTOCOL_REV_MAJOR(x)	(u16)(FIELD_GET(PROTOCOL_REV_MAJOR_MASK, (x)))
25 #define PROTOCOL_REV_MINOR(x)	(u16)(FIELD_GET(PROTOCOL_REV_MINOR_MASK, (x)))
26 #define MAX_PROTOCOLS_IMP	16
27 #define MAX_OPPS		16
28 
29 enum scmi_common_cmd {
30 	PROTOCOL_VERSION = 0x0,
31 	PROTOCOL_ATTRIBUTES = 0x1,
32 	PROTOCOL_MESSAGE_ATTRIBUTES = 0x2,
33 };
34 
35 /**
36  * struct scmi_msg_resp_prot_version - Response for a message
37  *
38  * @minor_version: Minor version of the ABI that firmware supports
39  * @major_version: Major version of the ABI that firmware supports
40  *
41  * In general, ABI version changes follow the rule that minor version increments
42  * are backward compatible. Major revision changes in ABI may not be
43  * backward compatible.
44  *
45  * Response to a generic message with message type SCMI_MSG_VERSION
46  */
47 struct scmi_msg_resp_prot_version {
48 	__le16 minor_version;
49 	__le16 major_version;
50 };
51 
52 #define MSG_ID_MASK		GENMASK(7, 0)
53 #define MSG_XTRACT_ID(hdr)	FIELD_GET(MSG_ID_MASK, (hdr))
54 #define MSG_TYPE_MASK		GENMASK(9, 8)
55 #define MSG_XTRACT_TYPE(hdr)	FIELD_GET(MSG_TYPE_MASK, (hdr))
56 #define MSG_TYPE_COMMAND	0
57 #define MSG_TYPE_DELAYED_RESP	2
58 #define MSG_TYPE_NOTIFICATION	3
59 #define MSG_PROTOCOL_ID_MASK	GENMASK(17, 10)
60 #define MSG_XTRACT_PROT_ID(hdr)	FIELD_GET(MSG_PROTOCOL_ID_MASK, (hdr))
61 #define MSG_TOKEN_ID_MASK	GENMASK(27, 18)
62 #define MSG_XTRACT_TOKEN(hdr)	FIELD_GET(MSG_TOKEN_ID_MASK, (hdr))
63 #define MSG_TOKEN_MAX		(MSG_XTRACT_TOKEN(MSG_TOKEN_ID_MASK) + 1)
64 
65 /**
66  * struct scmi_msg_hdr - Message(Tx/Rx) header
67  *
68  * @id: The identifier of the message being sent
69  * @protocol_id: The identifier of the protocol used to send @id message
70  * @seq: The token to identify the message. When a message returns, the
71  *	platform returns the whole message header unmodified including the
72  *	token
73  * @status: Status of the transfer once it's complete
74  * @poll_completion: Indicate if the transfer needs to be polled for
75  *	completion or interrupt mode is used
76  */
77 struct scmi_msg_hdr {
78 	u8 id;
79 	u8 protocol_id;
80 	u16 seq;
81 	u32 status;
82 	bool poll_completion;
83 };
84 
85 /**
86  * pack_scmi_header() - packs and returns 32-bit header
87  *
88  * @hdr: pointer to header containing all the information on message id,
89  *	protocol id and sequence id.
90  *
91  * Return: 32-bit packed message header to be sent to the platform.
92  */
93 static inline u32 pack_scmi_header(struct scmi_msg_hdr *hdr)
94 {
95 	return FIELD_PREP(MSG_ID_MASK, hdr->id) |
96 		FIELD_PREP(MSG_TOKEN_ID_MASK, hdr->seq) |
97 		FIELD_PREP(MSG_PROTOCOL_ID_MASK, hdr->protocol_id);
98 }
99 
100 /**
101  * unpack_scmi_header() - unpacks and records message and protocol id
102  *
103  * @msg_hdr: 32-bit packed message header sent from the platform
104  * @hdr: pointer to header to fetch message and protocol id.
105  */
106 static inline void unpack_scmi_header(u32 msg_hdr, struct scmi_msg_hdr *hdr)
107 {
108 	hdr->id = MSG_XTRACT_ID(msg_hdr);
109 	hdr->protocol_id = MSG_XTRACT_PROT_ID(msg_hdr);
110 }
111 
112 /**
113  * struct scmi_msg - Message(Tx/Rx) structure
114  *
115  * @buf: Buffer pointer
116  * @len: Length of data in the Buffer
117  */
118 struct scmi_msg {
119 	void *buf;
120 	size_t len;
121 };
122 
123 /**
124  * struct scmi_xfer - Structure representing a message flow
125  *
126  * @transfer_id: Unique ID for debug & profiling purpose
127  * @hdr: Transmit message header
128  * @tx: Transmit message
129  * @rx: Receive message, the buffer should be pre-allocated to store
130  *	message. If request-ACK protocol is used, we can reuse the same
131  *	buffer for the rx path as we use for the tx path.
132  * @done: command message transmit completion event
133  * @async_done: pointer to delayed response message received event completion
134  */
135 struct scmi_xfer {
136 	int transfer_id;
137 	struct scmi_msg_hdr hdr;
138 	struct scmi_msg tx;
139 	struct scmi_msg rx;
140 	struct completion done;
141 	struct completion *async_done;
142 };
143 
144 void scmi_xfer_put(const struct scmi_handle *h, struct scmi_xfer *xfer);
145 int scmi_do_xfer(const struct scmi_handle *h, struct scmi_xfer *xfer);
146 int scmi_do_xfer_with_response(const struct scmi_handle *h,
147 			       struct scmi_xfer *xfer);
148 int scmi_xfer_get_init(const struct scmi_handle *h, u8 msg_id, u8 prot_id,
149 		       size_t tx_size, size_t rx_size, struct scmi_xfer **p);
150 int scmi_handle_put(const struct scmi_handle *handle);
151 struct scmi_handle *scmi_handle_get(struct device *dev);
152 void scmi_set_handle(struct scmi_device *scmi_dev);
153 int scmi_version_get(const struct scmi_handle *h, u8 protocol, u32 *version);
154 void scmi_setup_protocol_implemented(const struct scmi_handle *handle,
155 				     u8 *prot_imp);
156 
157 int scmi_base_protocol_init(struct scmi_handle *h);
158 
159 /* SCMI Transport */
160 /**
161  * struct scmi_chan_info - Structure representing a SCMI channel information
162  *
163  * @dev: Reference to device in the SCMI hierarchy corresponding to this
164  *	 channel
165  * @handle: Pointer to SCMI entity handle
166  * @transport_info: Transport layer related information
167  */
168 struct scmi_chan_info {
169 	struct device *dev;
170 	struct scmi_handle *handle;
171 	void *transport_info;
172 };
173 
174 /**
175  * struct scmi_transport_ops - Structure representing a SCMI transport ops
176  *
177  * @chan_available: Callback to check if channel is available or not
178  * @chan_setup: Callback to allocate and setup a channel
179  * @chan_free: Callback to free a channel
180  * @send_message: Callback to send a message
181  * @mark_txdone: Callback to mark tx as done
182  * @fetch_response: Callback to fetch response
183  * @fetch_notification: Callback to fetch notification
184  * @clear_channel: Callback to clear a channel
185  * @poll_done: Callback to poll transfer status
186  */
187 struct scmi_transport_ops {
188 	bool (*chan_available)(struct device *dev, int idx);
189 	int (*chan_setup)(struct scmi_chan_info *cinfo, struct device *dev,
190 			  bool tx);
191 	int (*chan_free)(int id, void *p, void *data);
192 	int (*send_message)(struct scmi_chan_info *cinfo,
193 			    struct scmi_xfer *xfer);
194 	void (*mark_txdone)(struct scmi_chan_info *cinfo, int ret);
195 	void (*fetch_response)(struct scmi_chan_info *cinfo,
196 			       struct scmi_xfer *xfer);
197 	void (*fetch_notification)(struct scmi_chan_info *cinfo,
198 				   size_t max_len, struct scmi_xfer *xfer);
199 	void (*clear_channel)(struct scmi_chan_info *cinfo);
200 	bool (*poll_done)(struct scmi_chan_info *cinfo, struct scmi_xfer *xfer);
201 };
202 
203 /**
204  * struct scmi_desc - Description of SoC integration
205  *
206  * @ops: Pointer to the transport specific ops structure
207  * @max_rx_timeout_ms: Timeout for communication with SoC (in Milliseconds)
208  * @max_msg: Maximum number of messages that can be pending
209  *	simultaneously in the system
210  * @max_msg_size: Maximum size of data per message that can be handled.
211  */
212 struct scmi_desc {
213 	struct scmi_transport_ops *ops;
214 	int max_rx_timeout_ms;
215 	int max_msg;
216 	int max_msg_size;
217 };
218 
219 extern const struct scmi_desc scmi_mailbox_desc;
220 #ifdef CONFIG_HAVE_ARM_SMCCC
221 extern const struct scmi_desc scmi_smc_desc;
222 #endif
223 
224 void scmi_rx_callback(struct scmi_chan_info *cinfo, u32 msg_hdr);
225 void scmi_free_channel(struct scmi_chan_info *cinfo, struct idr *idr, int id);
226 
227 /* shmem related declarations */
228 struct scmi_shared_mem;
229 
230 void shmem_tx_prepare(struct scmi_shared_mem __iomem *shmem,
231 		      struct scmi_xfer *xfer);
232 u32 shmem_read_header(struct scmi_shared_mem __iomem *shmem);
233 void shmem_fetch_response(struct scmi_shared_mem __iomem *shmem,
234 			  struct scmi_xfer *xfer);
235 void shmem_fetch_notification(struct scmi_shared_mem __iomem *shmem,
236 			      size_t max_len, struct scmi_xfer *xfer);
237 void shmem_clear_channel(struct scmi_shared_mem __iomem *shmem);
238 bool shmem_poll_done(struct scmi_shared_mem __iomem *shmem,
239 		     struct scmi_xfer *xfer);
240 
241 #endif /* _SCMI_COMMON_H */
242