1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * System Control and Management Interface (SCMI) Message SMC/HVC
4 * Transport driver
5 *
6 * Copyright 2020 NXP
7 */
8
9 #include <linux/arm-smccc.h>
10 #include <linux/device.h>
11 #include <linux/err.h>
12 #include <linux/mutex.h>
13 #include <linux/of.h>
14 #include <linux/of_address.h>
15 #include <linux/slab.h>
16
17 #include "common.h"
18
19 /**
20 * struct scmi_smc - Structure representing a SCMI smc transport
21 *
22 * @cinfo: SCMI channel info
23 * @shmem: Transmit/Receive shared memory area
24 * @shmem_lock: Lock to protect access to Tx/Rx shared memory area
25 * @func_id: smc/hvc call function id
26 */
27
28 struct scmi_smc {
29 struct scmi_chan_info *cinfo;
30 struct scmi_shared_mem __iomem *shmem;
31 struct mutex shmem_lock;
32 u32 func_id;
33 };
34
smc_chan_available(struct device * dev,int idx)35 static bool smc_chan_available(struct device *dev, int idx)
36 {
37 struct device_node *np = of_parse_phandle(dev->of_node, "shmem", 0);
38 if (!np)
39 return false;
40
41 of_node_put(np);
42 return true;
43 }
44
smc_chan_setup(struct scmi_chan_info * cinfo,struct device * dev,bool tx)45 static int smc_chan_setup(struct scmi_chan_info *cinfo, struct device *dev,
46 bool tx)
47 {
48 struct device *cdev = cinfo->dev;
49 struct scmi_smc *scmi_info;
50 resource_size_t size;
51 struct resource res;
52 struct device_node *np;
53 u32 func_id;
54 int ret;
55
56 if (!tx)
57 return -ENODEV;
58
59 scmi_info = devm_kzalloc(dev, sizeof(*scmi_info), GFP_KERNEL);
60 if (!scmi_info)
61 return -ENOMEM;
62
63 np = of_parse_phandle(cdev->of_node, "shmem", 0);
64 ret = of_address_to_resource(np, 0, &res);
65 of_node_put(np);
66 if (ret) {
67 dev_err(cdev, "failed to get SCMI Tx shared memory\n");
68 return ret;
69 }
70
71 size = resource_size(&res);
72 scmi_info->shmem = devm_ioremap(dev, res.start, size);
73 if (!scmi_info->shmem) {
74 dev_err(dev, "failed to ioremap SCMI Tx shared memory\n");
75 return -EADDRNOTAVAIL;
76 }
77
78 ret = of_property_read_u32(dev->of_node, "arm,smc-id", &func_id);
79 if (ret < 0)
80 return ret;
81
82 scmi_info->func_id = func_id;
83 scmi_info->cinfo = cinfo;
84 mutex_init(&scmi_info->shmem_lock);
85 cinfo->transport_info = scmi_info;
86
87 return 0;
88 }
89
smc_chan_free(int id,void * p,void * data)90 static int smc_chan_free(int id, void *p, void *data)
91 {
92 struct scmi_chan_info *cinfo = p;
93 struct scmi_smc *scmi_info = cinfo->transport_info;
94
95 cinfo->transport_info = NULL;
96 scmi_info->cinfo = NULL;
97
98 scmi_free_channel(cinfo, data, id);
99
100 return 0;
101 }
102
smc_send_message(struct scmi_chan_info * cinfo,struct scmi_xfer * xfer)103 static int smc_send_message(struct scmi_chan_info *cinfo,
104 struct scmi_xfer *xfer)
105 {
106 struct scmi_smc *scmi_info = cinfo->transport_info;
107 struct arm_smccc_res res;
108
109 mutex_lock(&scmi_info->shmem_lock);
110
111 shmem_tx_prepare(scmi_info->shmem, xfer);
112
113 arm_smccc_1_1_invoke(scmi_info->func_id, 0, 0, 0, 0, 0, 0, 0, &res);
114 scmi_rx_callback(scmi_info->cinfo, shmem_read_header(scmi_info->shmem));
115
116 mutex_unlock(&scmi_info->shmem_lock);
117
118 /* Only SMCCC_RET_NOT_SUPPORTED is valid error code */
119 if (res.a0)
120 return -EOPNOTSUPP;
121 return 0;
122 }
123
smc_fetch_response(struct scmi_chan_info * cinfo,struct scmi_xfer * xfer)124 static void smc_fetch_response(struct scmi_chan_info *cinfo,
125 struct scmi_xfer *xfer)
126 {
127 struct scmi_smc *scmi_info = cinfo->transport_info;
128
129 shmem_fetch_response(scmi_info->shmem, xfer);
130 }
131
132 static bool
smc_poll_done(struct scmi_chan_info * cinfo,struct scmi_xfer * xfer)133 smc_poll_done(struct scmi_chan_info *cinfo, struct scmi_xfer *xfer)
134 {
135 struct scmi_smc *scmi_info = cinfo->transport_info;
136
137 return shmem_poll_done(scmi_info->shmem, xfer);
138 }
139
140 static const struct scmi_transport_ops scmi_smc_ops = {
141 .chan_available = smc_chan_available,
142 .chan_setup = smc_chan_setup,
143 .chan_free = smc_chan_free,
144 .send_message = smc_send_message,
145 .fetch_response = smc_fetch_response,
146 .poll_done = smc_poll_done,
147 };
148
149 const struct scmi_desc scmi_smc_desc = {
150 .ops = &scmi_smc_ops,
151 .max_rx_timeout_ms = 30,
152 .max_msg = 20,
153 .max_msg_size = 128,
154 };
155