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 
10 #include <linux/bitfield.h>
11 #include <linux/completion.h>
12 #include <linux/device.h>
13 #include <linux/errno.h>
14 #include <linux/kernel.h>
15 #include <linux/scmi_protocol.h>
16 #include <linux/types.h>
17 
18 #define PROTOCOL_REV_MINOR_MASK	GENMASK(15, 0)
19 #define PROTOCOL_REV_MAJOR_MASK	GENMASK(31, 16)
20 #define PROTOCOL_REV_MAJOR(x)	(u16)(FIELD_GET(PROTOCOL_REV_MAJOR_MASK, (x)))
21 #define PROTOCOL_REV_MINOR(x)	(u16)(FIELD_GET(PROTOCOL_REV_MINOR_MASK, (x)))
22 #define MAX_PROTOCOLS_IMP	16
23 #define MAX_OPPS		16
24 
25 enum scmi_common_cmd {
26 	PROTOCOL_VERSION = 0x0,
27 	PROTOCOL_ATTRIBUTES = 0x1,
28 	PROTOCOL_MESSAGE_ATTRIBUTES = 0x2,
29 };
30 
31 /**
32  * struct scmi_msg_resp_prot_version - Response for a message
33  *
34  * @major_version: Major version of the ABI that firmware supports
35  * @minor_version: Minor version of the ABI that firmware supports
36  *
37  * In general, ABI version changes follow the rule that minor version increments
38  * are backward compatible. Major revision changes in ABI may not be
39  * backward compatible.
40  *
41  * Response to a generic message with message type SCMI_MSG_VERSION
42  */
43 struct scmi_msg_resp_prot_version {
44 	__le16 minor_version;
45 	__le16 major_version;
46 };
47 
48 /**
49  * struct scmi_msg_hdr - Message(Tx/Rx) header
50  *
51  * @id: The identifier of the command being sent
52  * @protocol_id: The identifier of the protocol used to send @id command
53  * @seq: The token to identify the message. when a message/command returns,
54  *	the platform returns the whole message header unmodified including
55  *	the token
56  * @status: Status of the transfer once it's complete
57  * @poll_completion: Indicate if the transfer needs to be polled for
58  *	completion or interrupt mode is used
59  */
60 struct scmi_msg_hdr {
61 	u8 id;
62 	u8 protocol_id;
63 	u16 seq;
64 	u32 status;
65 	bool poll_completion;
66 };
67 
68 /**
69  * struct scmi_msg - Message(Tx/Rx) structure
70  *
71  * @buf: Buffer pointer
72  * @len: Length of data in the Buffer
73  */
74 struct scmi_msg {
75 	void *buf;
76 	size_t len;
77 };
78 
79 /**
80  * struct scmi_xfer - Structure representing a message flow
81  *
82  * @hdr: Transmit message header
83  * @tx: Transmit message
84  * @rx: Receive message, the buffer should be pre-allocated to store
85  *	message. If request-ACK protocol is used, we can reuse the same
86  *	buffer for the rx path as we use for the tx path.
87  * @done: completion event
88  */
89 struct scmi_xfer {
90 	struct scmi_msg_hdr hdr;
91 	struct scmi_msg tx;
92 	struct scmi_msg rx;
93 	struct completion done;
94 };
95 
96 void scmi_xfer_put(const struct scmi_handle *h, struct scmi_xfer *xfer);
97 int scmi_do_xfer(const struct scmi_handle *h, struct scmi_xfer *xfer);
98 int scmi_xfer_get_init(const struct scmi_handle *h, u8 msg_id, u8 prot_id,
99 		       size_t tx_size, size_t rx_size, struct scmi_xfer **p);
100 int scmi_handle_put(const struct scmi_handle *handle);
101 struct scmi_handle *scmi_handle_get(struct device *dev);
102 void scmi_set_handle(struct scmi_device *scmi_dev);
103 int scmi_version_get(const struct scmi_handle *h, u8 protocol, u32 *version);
104 void scmi_setup_protocol_implemented(const struct scmi_handle *handle,
105 				     u8 *prot_imp);
106 
107 int scmi_base_protocol_init(struct scmi_handle *h);
108