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