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 if (!of_device_is_compatible(np, "arm,scmi-shmem")) {
80 of_node_put(np);
81 return -ENXIO;
82 }
83
84 ret = of_address_to_resource(np, 0, &res);
85 of_node_put(np);
86 if (ret) {
87 dev_err(cdev, "failed to get SCMI Tx shared memory\n");
88 return ret;
89 }
90
91 size = resource_size(&res);
92 scmi_info->shmem = devm_ioremap(dev, res.start, size);
93 if (!scmi_info->shmem) {
94 dev_err(dev, "failed to ioremap SCMI Tx shared memory\n");
95 return -EADDRNOTAVAIL;
96 }
97
98 ret = of_property_read_u32(dev->of_node, "arm,smc-id", &func_id);
99 if (ret < 0)
100 return ret;
101
102 /*
103 * If there is an interrupt named "a2p", then the service and
104 * completion of a message is signaled by an interrupt rather than by
105 * the return of the SMC call.
106 */
107 irq = of_irq_get_byname(cdev->of_node, "a2p");
108 if (irq > 0) {
109 ret = devm_request_irq(dev, irq, smc_msg_done_isr,
110 IRQF_NO_SUSPEND,
111 dev_name(dev), scmi_info);
112 if (ret) {
113 dev_err(dev, "failed to setup SCMI smc irq\n");
114 return ret;
115 }
116 init_completion(&scmi_info->tx_complete);
117 scmi_info->irq = irq;
118 }
119
120 scmi_info->func_id = func_id;
121 scmi_info->cinfo = cinfo;
122 mutex_init(&scmi_info->shmem_lock);
123 cinfo->transport_info = scmi_info;
124
125 return 0;
126 }
127
smc_chan_free(int id,void * p,void * data)128 static int smc_chan_free(int id, void *p, void *data)
129 {
130 struct scmi_chan_info *cinfo = p;
131 struct scmi_smc *scmi_info = cinfo->transport_info;
132
133 cinfo->transport_info = NULL;
134 scmi_info->cinfo = NULL;
135
136 scmi_free_channel(cinfo, data, id);
137
138 return 0;
139 }
140
smc_send_message(struct scmi_chan_info * cinfo,struct scmi_xfer * xfer)141 static int smc_send_message(struct scmi_chan_info *cinfo,
142 struct scmi_xfer *xfer)
143 {
144 struct scmi_smc *scmi_info = cinfo->transport_info;
145 struct arm_smccc_res res;
146
147 mutex_lock(&scmi_info->shmem_lock);
148
149 shmem_tx_prepare(scmi_info->shmem, xfer);
150
151 if (scmi_info->irq)
152 reinit_completion(&scmi_info->tx_complete);
153
154 arm_smccc_1_1_invoke(scmi_info->func_id, 0, 0, 0, 0, 0, 0, 0, &res);
155
156 if (scmi_info->irq)
157 wait_for_completion(&scmi_info->tx_complete);
158
159 scmi_rx_callback(scmi_info->cinfo,
160 shmem_read_header(scmi_info->shmem), NULL);
161
162 mutex_unlock(&scmi_info->shmem_lock);
163
164 /* Only SMCCC_RET_NOT_SUPPORTED is valid error code */
165 if (res.a0)
166 return -EOPNOTSUPP;
167 return 0;
168 }
169
smc_fetch_response(struct scmi_chan_info * cinfo,struct scmi_xfer * xfer)170 static void smc_fetch_response(struct scmi_chan_info *cinfo,
171 struct scmi_xfer *xfer)
172 {
173 struct scmi_smc *scmi_info = cinfo->transport_info;
174
175 shmem_fetch_response(scmi_info->shmem, xfer);
176 }
177
178 static bool
smc_poll_done(struct scmi_chan_info * cinfo,struct scmi_xfer * xfer)179 smc_poll_done(struct scmi_chan_info *cinfo, struct scmi_xfer *xfer)
180 {
181 struct scmi_smc *scmi_info = cinfo->transport_info;
182
183 return shmem_poll_done(scmi_info->shmem, xfer);
184 }
185
186 static const struct scmi_transport_ops scmi_smc_ops = {
187 .chan_available = smc_chan_available,
188 .chan_setup = smc_chan_setup,
189 .chan_free = smc_chan_free,
190 .send_message = smc_send_message,
191 .fetch_response = smc_fetch_response,
192 .poll_done = smc_poll_done,
193 };
194
195 const struct scmi_desc scmi_smc_desc = {
196 .ops = &scmi_smc_ops,
197 .max_rx_timeout_ms = 30,
198 .max_msg = 20,
199 .max_msg_size = 128,
200 };
201