1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Microchip PolarFire SoC (MPFS) system controller driver
4 *
5 * Copyright (c) 2020-2021 Microchip Corporation. All rights reserved.
6 *
7 * Author: Conor Dooley <conor.dooley@microchip.com>
8 *
9 */
10
11 #include <linux/slab.h>
12 #include <linux/kref.h>
13 #include <linux/module.h>
14 #include <linux/interrupt.h>
15 #include <linux/of_platform.h>
16 #include <linux/mailbox_client.h>
17 #include <linux/platform_device.h>
18 #include <soc/microchip/mpfs.h>
19
20 static DEFINE_MUTEX(transaction_lock);
21
22 struct mpfs_sys_controller {
23 struct mbox_client client;
24 struct mbox_chan *chan;
25 struct completion c;
26 struct kref consumers;
27 };
28
mpfs_blocking_transaction(struct mpfs_sys_controller * sys_controller,struct mpfs_mss_msg * msg)29 int mpfs_blocking_transaction(struct mpfs_sys_controller *sys_controller, struct mpfs_mss_msg *msg)
30 {
31 int ret, err;
32
33 err = mutex_lock_interruptible(&transaction_lock);
34 if (err)
35 return err;
36
37 reinit_completion(&sys_controller->c);
38
39 ret = mbox_send_message(sys_controller->chan, msg);
40 if (ret >= 0) {
41 if (wait_for_completion_timeout(&sys_controller->c, HZ)) {
42 ret = 0;
43 } else {
44 ret = -ETIMEDOUT;
45 dev_warn(sys_controller->client.dev,
46 "MPFS sys controller transaction timeout\n");
47 }
48 } else {
49 dev_err(sys_controller->client.dev,
50 "mpfs sys controller transaction returned %d\n", ret);
51 }
52
53 mutex_unlock(&transaction_lock);
54
55 return ret;
56 }
57 EXPORT_SYMBOL(mpfs_blocking_transaction);
58
rx_callback(struct mbox_client * client,void * msg)59 static void rx_callback(struct mbox_client *client, void *msg)
60 {
61 struct mpfs_sys_controller *sys_controller =
62 container_of(client, struct mpfs_sys_controller, client);
63
64 complete(&sys_controller->c);
65 }
66
mpfs_sys_controller_delete(struct kref * kref)67 static void mpfs_sys_controller_delete(struct kref *kref)
68 {
69 struct mpfs_sys_controller *sys_controller = container_of(kref, struct mpfs_sys_controller,
70 consumers);
71
72 mbox_free_channel(sys_controller->chan);
73 kfree(sys_controller);
74 }
75
mpfs_sys_controller_put(void * data)76 static void mpfs_sys_controller_put(void *data)
77 {
78 struct mpfs_sys_controller *sys_controller = data;
79
80 kref_put(&sys_controller->consumers, mpfs_sys_controller_delete);
81 }
82
83 static struct platform_device subdevs[] = {
84 {
85 .name = "mpfs-rng",
86 .id = -1,
87 },
88 {
89 .name = "mpfs-generic-service",
90 .id = -1,
91 }
92 };
93
mpfs_sys_controller_probe(struct platform_device * pdev)94 static int mpfs_sys_controller_probe(struct platform_device *pdev)
95 {
96 struct device *dev = &pdev->dev;
97 struct mpfs_sys_controller *sys_controller;
98 int i, ret;
99
100 sys_controller = kzalloc(sizeof(*sys_controller), GFP_KERNEL);
101 if (!sys_controller)
102 return -ENOMEM;
103
104 sys_controller->client.dev = dev;
105 sys_controller->client.rx_callback = rx_callback;
106 sys_controller->client.tx_block = 1U;
107
108 sys_controller->chan = mbox_request_channel(&sys_controller->client, 0);
109 if (IS_ERR(sys_controller->chan)) {
110 ret = dev_err_probe(dev, PTR_ERR(sys_controller->chan),
111 "Failed to get mbox channel\n");
112 kfree(sys_controller);
113 return ret;
114 }
115
116 init_completion(&sys_controller->c);
117 kref_init(&sys_controller->consumers);
118
119 platform_set_drvdata(pdev, sys_controller);
120
121 dev_info(&pdev->dev, "Registered MPFS system controller\n");
122
123 for (i = 0; i < ARRAY_SIZE(subdevs); i++) {
124 subdevs[i].dev.parent = dev;
125 if (platform_device_register(&subdevs[i]))
126 dev_warn(dev, "Error registering sub device %s\n", subdevs[i].name);
127 }
128
129 return 0;
130 }
131
mpfs_sys_controller_remove(struct platform_device * pdev)132 static int mpfs_sys_controller_remove(struct platform_device *pdev)
133 {
134 struct mpfs_sys_controller *sys_controller = platform_get_drvdata(pdev);
135
136 mpfs_sys_controller_put(sys_controller);
137
138 return 0;
139 }
140
141 static const struct of_device_id mpfs_sys_controller_of_match[] = {
142 {.compatible = "microchip,mpfs-sys-controller", },
143 {},
144 };
145 MODULE_DEVICE_TABLE(of, mpfs_sys_controller_of_match);
146
mpfs_sys_controller_get(struct device * dev)147 struct mpfs_sys_controller *mpfs_sys_controller_get(struct device *dev)
148 {
149 const struct of_device_id *match;
150 struct mpfs_sys_controller *sys_controller;
151 int ret;
152
153 if (!dev->parent)
154 goto err_no_device;
155
156 match = of_match_node(mpfs_sys_controller_of_match, dev->parent->of_node);
157 of_node_put(dev->parent->of_node);
158 if (!match)
159 goto err_no_device;
160
161 sys_controller = dev_get_drvdata(dev->parent);
162 if (!sys_controller)
163 goto err_bad_device;
164
165 if (!kref_get_unless_zero(&sys_controller->consumers))
166 goto err_bad_device;
167
168 ret = devm_add_action_or_reset(dev, mpfs_sys_controller_put, sys_controller);
169 if (ret)
170 return ERR_PTR(ret);
171
172 return sys_controller;
173
174 err_no_device:
175 dev_dbg(dev, "Parent device was not an MPFS system controller\n");
176 return ERR_PTR(-ENODEV);
177
178 err_bad_device:
179 dev_dbg(dev, "MPFS system controller found but could not register as a sub device\n");
180 return ERR_PTR(-EPROBE_DEFER);
181 }
182 EXPORT_SYMBOL(mpfs_sys_controller_get);
183
184 static struct platform_driver mpfs_sys_controller_driver = {
185 .driver = {
186 .name = "mpfs-sys-controller",
187 .of_match_table = mpfs_sys_controller_of_match,
188 },
189 .probe = mpfs_sys_controller_probe,
190 .remove = mpfs_sys_controller_remove,
191 };
192 module_platform_driver(mpfs_sys_controller_driver);
193
194 MODULE_LICENSE("GPL v2");
195 MODULE_AUTHOR("Conor Dooley <conor.dooley@microchip.com>");
196 MODULE_DESCRIPTION("MPFS system controller driver");
197