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