1/* SPDX-License-Identifier: GPL-2.0-only */
2/* Copyright(c) 2024 Intel Corporation. */
3#ifndef __CXL_MBOX_H__
4#define __CXL_MBOX_H__
5#include <linux/rcuwait.h>
6#include <cxl/features.h>
7#include <uapi/linux/cxl_mem.h>
8
9/**
10 * struct cxl_mbox_cmd - A command to be submitted to hardware.
11 * @opcode: (input) The command set and command submitted to hardware.
12 * @payload_in: (input) Pointer to the input payload.
13 * @payload_out: (output) Pointer to the output payload. Must be allocated by
14 * the caller.
15 * @size_in: (input) Number of bytes to load from @payload_in.
16 * @size_out: (input) Max number of bytes loaded into @payload_out.
17 * (output) Number of bytes generated by the device. For fixed size
18 * outputs commands this is always expected to be deterministic. For
19 * variable sized output commands, it tells the exact number of bytes
20 * written.
21 * @min_out: (input) internal command output payload size validation
22 * @poll_count: (input) Number of timeouts to attempt.
23 * @poll_interval_ms: (input) Time between mailbox background command polling
24 * interval timeouts.
25 * @return_code: (output) Error code returned from hardware.
26 *
27 * This is the primary mechanism used to send commands to the hardware.
28 * All the fields except @payload_* correspond exactly to the fields described in
29 * Command Register section of the CXL 2.0 8.2.8.4.5. @payload_in and
30 * @payload_out are written to, and read from the Command Payload Registers
31 * defined in CXL 2.0 8.2.8.4.8.
32 */
33struct cxl_mbox_cmd {
34 u16 opcode;
35 void *payload_in;
36 void *payload_out;
37 size_t size_in;
38 size_t size_out;
39 size_t min_out;
40 int poll_count;
41 int poll_interval_ms;
42 u16 return_code;
43};
44
45/**
46 * struct cxl_mailbox - context for CXL mailbox operations
47 * @host: device that hosts the mailbox
48 * @enabled_cmds: mailbox commands that are enabled by the driver
49 * @exclusive_cmds: mailbox commands that are exclusive to the kernel
50 * @payload_size: Size of space for payload
51 * (CXL 3.1 8.2.8.4.3 Mailbox Capabilities Register)
52 * @mbox_mutex: mutex protects device mailbox and firmware
53 * @mbox_wait: rcuwait for mailbox
54 * @mbox_send: @dev specific transport for transmitting mailbox commands
55 * @feat_cap: Features capability
56 */
57struct cxl_mailbox {
58 struct device *host;
59 DECLARE_BITMAP(enabled_cmds, CXL_MEM_COMMAND_ID_MAX);
60 DECLARE_BITMAP(exclusive_cmds, CXL_MEM_COMMAND_ID_MAX);
61 size_t payload_size;
62 struct mutex mbox_mutex; /* lock to protect mailbox context */
63 struct rcuwait mbox_wait;
64 int (*mbox_send)(struct cxl_mailbox *cxl_mbox, struct cxl_mbox_cmd *cmd);
65 enum cxl_features_capability feat_cap;
66};
67
68int cxl_mailbox_init(struct cxl_mailbox *cxl_mbox, struct device *host);
69
70#endif
71

source code of linux/include/cxl/mailbox.h