1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3 * Copyright (C) 2020 Linaro Limited.
4 */
5
6 #include <common.h>
7 #include <dm.h>
8 #include <errno.h>
9 #include <scmi_agent.h>
10 #include <scmi_agent-uclass.h>
11 #include <dm/device-internal.h>
12 #include <dm/read.h>
13 #include <linux/arm-smccc.h>
14 #include <linux/compat.h>
15
16 #include "smt.h"
17
18 #define SMCCC_RET_NOT_SUPPORTED ((unsigned long)-1)
19
20 /**
21 * struct scmi_smccc_channel - Description of an SCMI SMCCC transport
22 * @func_id: SMCCC function ID used by the SCMI transport
23 * @smt: Shared memory buffer
24 */
25 struct scmi_smccc_channel {
26 ulong func_id;
27 struct scmi_smt smt;
28 };
29
30 #ifndef CONFIG_SPL_BUILD
scmi_smccc_process_msg(struct udevice * dev,struct scmi_msg * msg)31 static int scmi_smccc_process_msg(struct udevice *dev, struct scmi_msg *msg)
32 {
33 struct scmi_smccc_channel *chan = dev_get_priv(dev);
34 struct arm_smccc_res res;
35 int ret;
36
37 ret = scmi_write_msg_to_smt(dev, &chan->smt, msg);
38 if (ret)
39 return ret;
40
41 arm_smccc_smc(chan->func_id, 0, 0, 0, 0, 0, 0, 0, &res);
42 if (res.a0 == SMCCC_RET_NOT_SUPPORTED)
43 ret = -ENXIO;
44 else
45 ret = scmi_read_resp_from_smt(dev, &chan->smt, msg);
46
47 scmi_clear_smt_channel(&chan->smt);
48
49 return ret;
50 }
51
scmi_smccc_probe(struct udevice * dev)52 static int scmi_smccc_probe(struct udevice *dev)
53 {
54 struct scmi_smccc_channel *chan = dev_get_priv(dev);
55 u32 func_id;
56 int ret;
57
58 func_id = dev_read_u32_default(dev, "arm,smc-id", -ENODATA);
59 if (func_id == -ENODATA) {
60 dev_err(dev, "Missing property func-id\n");
61 return -EINVAL;
62 }
63
64 chan->func_id = func_id;
65
66 ret = scmi_dt_get_smt_buffer(dev, &chan->smt);
67 if (ret) {
68 dev_err(dev, "Failed to get smt resources: %d\n", ret);
69 return ret;
70 }
71
72 return 0;
73 }
74
75 static const struct scmi_agent_ops scmi_smccc_ops = {
76 .process_msg = scmi_smccc_process_msg,
77 };
78 #endif
79
80 static const struct udevice_id scmi_smccc_ids[] = {
81 { .compatible = "arm,scmi-smc" },
82 { }
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_alloc_size = sizeof(struct scmi_smccc_channel),
90 #ifndef CONFIG_SPL_BUILD
91 .probe = scmi_smccc_probe,
92 .ops = &scmi_smccc_ops,
93 #endif
94 };
95