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 <scmi_agent.h>
11 #include <scmi_agent-uclass.h>
12 #include <dm/devres.h>
13 #include <dm/device_compat.h>
14 #include <dm/device-internal.h>
15 #include <linux/arm-smccc.h>
16 #include <linux/compat.h>
17
18 #include "smt.h"
19
20 #define SMCCC_RET_NOT_SUPPORTED ((unsigned long)-1)
21
22 /**
23 * struct scmi_smccc_channel - Description of an SCMI SMCCC transport
24 * @func_id: SMCCC function ID used by the SCMI transport
25 * @smt: Shared memory buffer
26 */
27 struct scmi_smccc_channel {
28 ulong func_id;
29 struct scmi_smt smt;
30 };
31
32 /**
33 * struct scmi_channel - Channel instance referenced in SCMI drivers
34 * @ref: Reference to local channel instance
35 **/
36 struct scmi_channel {
37 struct scmi_smccc_channel ref;
38 };
39
scmi_smccc_process_msg(struct udevice * dev,struct scmi_channel * channel,struct scmi_msg * msg)40 static int scmi_smccc_process_msg(struct udevice *dev,
41 struct scmi_channel *channel,
42 struct scmi_msg *msg)
43 {
44 struct scmi_smccc_channel *chan = &channel->ref;
45 struct arm_smccc_res res;
46 int ret;
47
48 ret = scmi_write_msg_to_smt(dev, &chan->smt, msg);
49 if (ret)
50 return ret;
51
52 arm_smccc_smc(chan->func_id, 0, 0, 0, 0, 0, 0, 0, &res);
53 if (res.a0 == SMCCC_RET_NOT_SUPPORTED)
54 ret = -ENXIO;
55 else
56 ret = scmi_read_resp_from_smt(dev, &chan->smt, msg);
57
58 scmi_clear_smt_channel(&chan->smt);
59
60 return ret;
61 }
62
setup_channel(struct udevice * dev,struct scmi_smccc_channel * chan)63 static int setup_channel(struct udevice *dev, struct scmi_smccc_channel *chan)
64 {
65 u32 func_id;
66 int ret;
67
68 if (dev_read_u32(dev, "arm,smc-id", &func_id)) {
69 dev_err(dev, "Missing property func-id\n");
70 return -EINVAL;
71 }
72
73 chan->func_id = func_id;
74
75 ret = scmi_dt_get_smt_buffer(dev, &chan->smt);
76 if (ret)
77 dev_err(dev, "Failed to get smt resources: %d\n", ret);
78
79 return ret;
80 }
81
scmi_smccc_get_channel(struct udevice * dev,struct udevice * protocol,struct scmi_channel ** channel)82 static int scmi_smccc_get_channel(struct udevice *dev,
83 struct udevice *protocol,
84 struct scmi_channel **channel)
85 {
86 struct scmi_smccc_channel *base_chan = dev_get_plat(dev);
87 struct scmi_smccc_channel *chan;
88 u32 func_id;
89 int ret;
90
91 if (dev_read_u32(protocol, "arm,smc-id", &func_id)) {
92 /* Uses agent base channel */
93 *channel = container_of(base_chan, struct scmi_channel, ref);
94
95 return 0;
96 }
97
98 /* Setup a dedicated channel */
99 chan = calloc(1, sizeof(*chan));
100 if (!chan)
101 return -ENOMEM;
102
103 ret = setup_channel(protocol, chan);
104 if (ret) {
105 free(chan);
106 return ret;
107 }
108
109 *channel = container_of(chan, struct scmi_channel, ref);
110
111 return 0;
112 }
113
scmi_smccc_of_to_plat(struct udevice * dev)114 static int scmi_smccc_of_to_plat(struct udevice *dev)
115 {
116 struct scmi_smccc_channel *chan = dev_get_plat(dev);
117
118 return setup_channel(dev, chan);
119 }
120
121 static const struct udevice_id scmi_smccc_ids[] = {
122 { .compatible = "arm,scmi-smc" },
123 { }
124 };
125
126 static const struct scmi_agent_ops scmi_smccc_ops = {
127 .of_get_channel = scmi_smccc_get_channel,
128 .process_msg = scmi_smccc_process_msg,
129 };
130
131 U_BOOT_DRIVER(scmi_smccc) = {
132 .name = "scmi-over-smccc",
133 .id = UCLASS_SCMI_AGENT,
134 .of_match = scmi_smccc_ids,
135 .plat_auto = sizeof(struct scmi_smccc_channel),
136 .of_to_plat = scmi_smccc_of_to_plat,
137 .ops = &scmi_smccc_ops,
138 };
139