1 | // SPDX-License-Identifier: GPL-2.0 |
2 | /* |
3 | * For transports using message passing. |
4 | * |
5 | * Derived from shm.c. |
6 | * |
7 | * Copyright (C) 2019-2021 ARM Ltd. |
8 | * Copyright (C) 2020-2021 OpenSynergy GmbH |
9 | */ |
10 | |
11 | #include <linux/types.h> |
12 | |
13 | #include "common.h" |
14 | |
15 | /* |
16 | * struct scmi_msg_payld - Transport SDU layout |
17 | * |
18 | * The SCMI specification requires all parameters, message headers, return |
19 | * arguments or any protocol data to be expressed in little endian format only. |
20 | */ |
21 | struct scmi_msg_payld { |
22 | __le32 ; |
23 | __le32 msg_payload[]; |
24 | }; |
25 | |
26 | /** |
27 | * msg_command_size() - Actual size of transport SDU for command. |
28 | * |
29 | * @xfer: message which core has prepared for sending |
30 | * |
31 | * Return: transport SDU size. |
32 | */ |
33 | size_t msg_command_size(struct scmi_xfer *xfer) |
34 | { |
35 | return sizeof(struct scmi_msg_payld) + xfer->tx.len; |
36 | } |
37 | |
38 | /** |
39 | * msg_response_size() - Maximum size of transport SDU for response. |
40 | * |
41 | * @xfer: message which core has prepared for sending |
42 | * |
43 | * Return: transport SDU size. |
44 | */ |
45 | size_t msg_response_size(struct scmi_xfer *xfer) |
46 | { |
47 | return sizeof(struct scmi_msg_payld) + sizeof(__le32) + xfer->rx.len; |
48 | } |
49 | |
50 | /** |
51 | * msg_tx_prepare() - Set up transport SDU for command. |
52 | * |
53 | * @msg: transport SDU for command |
54 | * @xfer: message which is being sent |
55 | */ |
56 | void msg_tx_prepare(struct scmi_msg_payld *msg, struct scmi_xfer *xfer) |
57 | { |
58 | msg->msg_header = cpu_to_le32(pack_scmi_header(&xfer->hdr)); |
59 | if (xfer->tx.buf) |
60 | memcpy(msg->msg_payload, xfer->tx.buf, xfer->tx.len); |
61 | } |
62 | |
63 | /** |
64 | * msg_read_header() - Read SCMI header from transport SDU. |
65 | * |
66 | * @msg: transport SDU |
67 | * |
68 | * Return: SCMI header |
69 | */ |
70 | u32 (struct scmi_msg_payld *msg) |
71 | { |
72 | return le32_to_cpu(msg->msg_header); |
73 | } |
74 | |
75 | /** |
76 | * msg_fetch_response() - Fetch response SCMI payload from transport SDU. |
77 | * |
78 | * @msg: transport SDU with response |
79 | * @len: transport SDU size |
80 | * @xfer: message being responded to |
81 | */ |
82 | void msg_fetch_response(struct scmi_msg_payld *msg, size_t len, |
83 | struct scmi_xfer *xfer) |
84 | { |
85 | size_t prefix_len = sizeof(*msg) + sizeof(msg->msg_payload[0]); |
86 | |
87 | xfer->hdr.status = le32_to_cpu(msg->msg_payload[0]); |
88 | xfer->rx.len = min_t(size_t, xfer->rx.len, |
89 | len >= prefix_len ? len - prefix_len : 0); |
90 | |
91 | /* Take a copy to the rx buffer.. */ |
92 | memcpy(xfer->rx.buf, &msg->msg_payload[1], xfer->rx.len); |
93 | } |
94 | |
95 | /** |
96 | * msg_fetch_notification() - Fetch notification payload from transport SDU. |
97 | * |
98 | * @msg: transport SDU with notification |
99 | * @len: transport SDU size |
100 | * @max_len: maximum SCMI payload size to fetch |
101 | * @xfer: notification message |
102 | */ |
103 | void msg_fetch_notification(struct scmi_msg_payld *msg, size_t len, |
104 | size_t max_len, struct scmi_xfer *xfer) |
105 | { |
106 | xfer->rx.len = min_t(size_t, max_len, |
107 | len >= sizeof(*msg) ? len - sizeof(*msg) : 0); |
108 | |
109 | /* Take a copy to the rx buffer.. */ |
110 | memcpy(xfer->rx.buf, msg->msg_payload, xfer->rx.len); |
111 | } |
112 | |