1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3 * Copyright (C) 2020 Linaro Limited.
4 */
5
6 #define LOG_CATEGORY UCLASS_SCMI_AGENT
7
8 #include <dm.h>
9 #include <errno.h>
10 #include <mailbox.h>
11 #include <scmi_agent.h>
12 #include <scmi_agent-uclass.h>
13 #include <dm/device_compat.h>
14 #include <dm/devres.h>
15 #include <linux/compat.h>
16
17 #include "smt.h"
18
19 #define TIMEOUT_US_10MS 10000
20
21 /**
22 * struct scmi_mbox_channel - Description of an SCMI mailbox transport
23 * @smt: Shared memory buffer
24 * @mbox: Mailbox channel description
25 * @timeout_us: Timeout in microseconds for the mailbox transfer
26 */
27 struct scmi_mbox_channel {
28 struct scmi_smt smt;
29 struct mbox_chan mbox;
30 ulong timeout_us;
31 };
32
33 /**
34 * struct scmi_channel - Channel instance referenced in SCMI drivers
35 * @ref: Reference to local channel instance
36 **/
37 struct scmi_channel {
38 struct scmi_mbox_channel ref;
39 };
40
scmi_mbox_process_msg(struct udevice * dev,struct scmi_channel * channel,struct scmi_msg * msg)41 static int scmi_mbox_process_msg(struct udevice *dev,
42 struct scmi_channel *channel,
43 struct scmi_msg *msg)
44 {
45 struct scmi_mbox_channel *chan = &channel->ref;
46 int ret;
47
48 ret = scmi_write_msg_to_smt(dev, &chan->smt, msg);
49 if (ret)
50 return ret;
51
52 /* Give shm addr to mbox in case it is meaningful */
53 ret = mbox_send(&chan->mbox, chan->smt.buf);
54 if (ret) {
55 dev_err(dev, "Message send failed: %d\n", ret);
56 goto out;
57 }
58
59 /* Receive the response */
60 ret = mbox_recv(&chan->mbox, chan->smt.buf, chan->timeout_us);
61 if (ret) {
62 dev_err(dev, "Response failed: %d, abort\n", ret);
63 goto out;
64 }
65
66 ret = scmi_read_resp_from_smt(dev, &chan->smt, msg);
67
68 out:
69 scmi_clear_smt_channel(&chan->smt);
70
71 return ret;
72 }
73
setup_channel(struct udevice * dev,struct scmi_mbox_channel * chan)74 static int setup_channel(struct udevice *dev, struct scmi_mbox_channel *chan)
75 {
76 int ret;
77
78 ret = mbox_get_by_index(dev, 0, &chan->mbox);
79 if (ret) {
80 dev_err(dev, "Failed to find mailbox: %d\n", ret);
81 return ret;
82 }
83
84 ret = scmi_dt_get_smt_buffer(dev, &chan->smt);
85 if (ret) {
86 dev_err(dev, "Failed to get shm resources: %d\n", ret);
87 return ret;
88 }
89
90 chan->timeout_us = TIMEOUT_US_10MS;
91
92 return 0;
93 }
94
scmi_mbox_get_channel(struct udevice * dev,struct udevice * protocol,struct scmi_channel ** channel)95 static int scmi_mbox_get_channel(struct udevice *dev,
96 struct udevice *protocol,
97 struct scmi_channel **channel)
98 {
99 struct scmi_mbox_channel *base_chan = dev_get_plat(dev);
100 struct scmi_mbox_channel *chan;
101 int ret;
102
103 if (!dev_read_prop(protocol, "shmem", NULL)) {
104 /* Uses agent base channel */
105 *channel = container_of(base_chan, struct scmi_channel, ref);
106
107 return 0;
108 }
109
110 chan = calloc(1, sizeof(*chan));
111 if (!chan)
112 return -ENOMEM;
113
114 /* Setup a dedicated channel for the protocol */
115 ret = setup_channel(protocol, chan);
116 if (ret) {
117 free(chan);
118 return ret;
119 }
120
121 *channel = (void *)chan;
122
123 return 0;
124 }
125
scmi_mbox_of_to_plat(struct udevice * dev)126 int scmi_mbox_of_to_plat(struct udevice *dev)
127 {
128 struct scmi_mbox_channel *chan = dev_get_plat(dev);
129
130 return setup_channel(dev, chan);
131 }
132
133 static const struct udevice_id scmi_mbox_ids[] = {
134 { .compatible = "arm,scmi" },
135 { }
136 };
137
138 static const struct scmi_agent_ops scmi_mbox_ops = {
139 .of_get_channel = scmi_mbox_get_channel,
140 .process_msg = scmi_mbox_process_msg,
141 };
142
143 U_BOOT_DRIVER(scmi_mbox) = {
144 .name = "scmi-over-mailbox",
145 .id = UCLASS_SCMI_AGENT,
146 .of_match = scmi_mbox_ids,
147 .plat_auto = sizeof(struct scmi_mbox_channel),
148 .of_to_plat = scmi_mbox_of_to_plat,
149 .ops = &scmi_mbox_ops,
150 };
151