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 <common.h>
9 #include <dm.h>
10 #include <errno.h>
11 #include <scmi_agent.h>
12 #include <scmi_agent-uclass.h>
13 #include <dm/devres.h>
14 #include <dm/device_compat.h>
15 #include <dm/device-internal.h>
16 #include <linux/arm-smccc.h>
17 #include <linux/compat.h>
18
19 #include "smt.h"
20
21 #define SMCCC_RET_NOT_SUPPORTED ((unsigned long)-1)
22
23 /**
24 * struct scmi_smccc_channel - Description of an SCMI SMCCC transport
25 * @func_id: SMCCC function ID used by the SCMI transport
26 * @smt: Shared memory buffer
27 */
28 struct scmi_smccc_channel {
29 ulong func_id;
30 struct scmi_smt smt;
31 };
32
scmi_smccc_process_msg(struct udevice * dev,struct scmi_msg * msg)33 static int scmi_smccc_process_msg(struct udevice *dev, struct scmi_msg *msg)
34 {
35 struct scmi_smccc_channel *chan = dev_get_priv(dev);
36 struct arm_smccc_res res;
37 int ret;
38
39 ret = scmi_write_msg_to_smt(dev, &chan->smt, msg);
40 if (ret)
41 return ret;
42
43 arm_smccc_smc(chan->func_id, 0, 0, 0, 0, 0, 0, 0, &res);
44 if (res.a0 == SMCCC_RET_NOT_SUPPORTED)
45 ret = -ENXIO;
46 else
47 ret = scmi_read_resp_from_smt(dev, &chan->smt, msg);
48
49 scmi_clear_smt_channel(&chan->smt);
50
51 return ret;
52 }
53
scmi_smccc_probe(struct udevice * dev)54 static int scmi_smccc_probe(struct udevice *dev)
55 {
56 struct scmi_smccc_channel *chan = dev_get_priv(dev);
57 u32 func_id;
58 int ret;
59
60 if (dev_read_u32(dev, "arm,smc-id", &func_id)) {
61 dev_err(dev, "Missing property func-id\n");
62 return -EINVAL;
63 }
64
65 chan->func_id = func_id;
66
67 ret = scmi_dt_get_smt_buffer(dev, &chan->smt);
68 if (ret) {
69 dev_err(dev, "Failed to get smt resources: %d\n", ret);
70 return ret;
71 }
72
73 return 0;
74 }
75
76 static const struct udevice_id scmi_smccc_ids[] = {
77 { .compatible = "arm,scmi-smc" },
78 { }
79 };
80
81 static const struct scmi_agent_ops scmi_smccc_ops = {
82 .process_msg = scmi_smccc_process_msg,
83 };
84
85 U_BOOT_DRIVER(scmi_smccc) = {
86 .name = "scmi-over-smccc",
87 .id = UCLASS_SCMI_AGENT,
88 .of_match = scmi_smccc_ids,
89 .priv_auto = sizeof(struct scmi_smccc_channel),
90 .probe = scmi_smccc_probe,
91 .ops = &scmi_smccc_ops,
92 };
93