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/interrupt.h>
13 #include <linux/mutex.h>
14 #include <linux/of.h>
15 #include <linux/of_address.h>
16 #include <linux/of_irq.h>
17 #include <linux/slab.h>
18
19 #include "common.h"
20
21 /**
22 * struct scmi_smc - Structure representing a SCMI smc transport
23 *
24 * @cinfo: SCMI channel info
25 * @shmem: Transmit/Receive shared memory area
26 * @shmem_lock: Lock to protect access to Tx/Rx shared memory area
27 * @func_id: smc/hvc call function id
28 * @irq: Optional; employed when platforms indicates msg completion by intr.
29 * @tx_complete: Optional, employed only when irq is valid.
30 */
31
32 struct scmi_smc {
33 struct scmi_chan_info *cinfo;
34 struct scmi_shared_mem __iomem *shmem;
35 struct mutex shmem_lock;
36 u32 func_id;
37 int irq;
38 struct completion tx_complete;
39 };
40
smc_msg_done_isr(int irq,void * data)41 static irqreturn_t smc_msg_done_isr(int irq, void *data)
42 {
43 struct scmi_smc *scmi_info = data;
44
45 complete(&scmi_info->tx_complete);
46
47 return IRQ_HANDLED;
48 }
49
smc_chan_available(struct device * dev,int idx)50 static bool smc_chan_available(struct device *dev, int idx)
51 {
52 struct device_node *np = of_parse_phandle(dev->of_node, "shmem", 0);
53 if (!np)
54 return false;
55
56 of_node_put(np);
57 return true;
58 }
59
smc_chan_setup(struct scmi_chan_info * cinfo,struct device * dev,bool tx)60 static int smc_chan_setup(struct scmi_chan_info *cinfo, struct device *dev,
61 bool tx)
62 {
63 struct device *cdev = cinfo->dev;
64 struct scmi_smc *scmi_info;
65 resource_size_t size;
66 struct resource res;
67 struct device_node *np;
68 u32 func_id;
69 int ret, irq;
70
71 if (!tx)
72 return -ENODEV;
73
74 scmi_info = devm_kzalloc(dev, sizeof(*scmi_info), GFP_KERNEL);
75 if (!scmi_info)
76 return -ENOMEM;
77
78 np = of_parse_phandle(cdev->of_node, "shmem", 0);
79 ret = of_address_to_resource(np, 0, &res);
80 of_node_put(np);
81 if (ret) {
82 dev_err(cdev, "failed to get SCMI Tx shared memory\n");
83 return ret;
84 }
85
86 size = resource_size(&res);
87 scmi_info->shmem = devm_ioremap(dev, res.start, size);
88 if (!scmi_info->shmem) {
89 dev_err(dev, "failed to ioremap SCMI Tx shared memory\n");
90 return -EADDRNOTAVAIL;
91 }
92
93 ret = of_property_read_u32(dev->of_node, "arm,smc-id", &func_id);
94 if (ret < 0)
95 return ret;
96
97 /*
98 * If there is an interrupt named "a2p", then the service and
99 * completion of a message is signaled by an interrupt rather than by
100 * the return of the SMC call.
101 */
102 irq = of_irq_get_byname(cdev->of_node, "a2p");
103 if (irq > 0) {
104 ret = devm_request_irq(dev, irq, smc_msg_done_isr,
105 IRQF_NO_SUSPEND,
106 dev_name(dev), scmi_info);
107 if (ret) {
108 dev_err(dev, "failed to setup SCMI smc irq\n");
109 return ret;
110 }
111 init_completion(&scmi_info->tx_complete);
112 scmi_info->irq = irq;
113 }
114
115 scmi_info->func_id = func_id;
116 scmi_info->cinfo = cinfo;
117 mutex_init(&scmi_info->shmem_lock);
118 cinfo->transport_info = scmi_info;
119
120 return 0;
121 }
122
smc_chan_free(int id,void * p,void * data)123 static int smc_chan_free(int id, void *p, void *data)
124 {
125 struct scmi_chan_info *cinfo = p;
126 struct scmi_smc *scmi_info = cinfo->transport_info;
127
128 cinfo->transport_info = NULL;
129 scmi_info->cinfo = NULL;
130
131 scmi_free_channel(cinfo, data, id);
132
133 return 0;
134 }
135
smc_send_message(struct scmi_chan_info * cinfo,struct scmi_xfer * xfer)136 static int smc_send_message(struct scmi_chan_info *cinfo,
137 struct scmi_xfer *xfer)
138 {
139 struct scmi_smc *scmi_info = cinfo->transport_info;
140 struct arm_smccc_res res;
141
142 mutex_lock(&scmi_info->shmem_lock);
143
144 shmem_tx_prepare(scmi_info->shmem, xfer);
145
146 if (scmi_info->irq)
147 reinit_completion(&scmi_info->tx_complete);
148
149 arm_smccc_1_1_invoke(scmi_info->func_id, 0, 0, 0, 0, 0, 0, 0, &res);
150
151 if (scmi_info->irq)
152 wait_for_completion(&scmi_info->tx_complete);
153
154 scmi_rx_callback(scmi_info->cinfo, shmem_read_header(scmi_info->shmem));
155
156 mutex_unlock(&scmi_info->shmem_lock);
157
158 /* Only SMCCC_RET_NOT_SUPPORTED is valid error code */
159 if (res.a0)
160 return -EOPNOTSUPP;
161 return 0;
162 }
163
smc_fetch_response(struct scmi_chan_info * cinfo,struct scmi_xfer * xfer)164 static void smc_fetch_response(struct scmi_chan_info *cinfo,
165 struct scmi_xfer *xfer)
166 {
167 struct scmi_smc *scmi_info = cinfo->transport_info;
168
169 shmem_fetch_response(scmi_info->shmem, xfer);
170 }
171
172 static bool
smc_poll_done(struct scmi_chan_info * cinfo,struct scmi_xfer * xfer)173 smc_poll_done(struct scmi_chan_info *cinfo, struct scmi_xfer *xfer)
174 {
175 struct scmi_smc *scmi_info = cinfo->transport_info;
176
177 return shmem_poll_done(scmi_info->shmem, xfer);
178 }
179
180 static const struct scmi_transport_ops scmi_smc_ops = {
181 .chan_available = smc_chan_available,
182 .chan_setup = smc_chan_setup,
183 .chan_free = smc_chan_free,
184 .send_message = smc_send_message,
185 .fetch_response = smc_fetch_response,
186 .poll_done = smc_poll_done,
187 };
188
189 const struct scmi_desc scmi_smc_desc = {
190 .ops = &scmi_smc_ops,
191 .max_rx_timeout_ms = 30,
192 .max_msg = 20,
193 .max_msg_size = 128,
194 };
195