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
 20static DEFINE_MUTEX(transaction_lock);
 21
 22struct mpfs_sys_controller {
 23	struct mbox_client client;
 24	struct mbox_chan *chan;
 25	struct completion c;
 26	struct kref consumers;
 27};
 28
 29int 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}
 57EXPORT_SYMBOL(mpfs_blocking_transaction);
 58
 59static 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
 67static 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
 76static 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
 83static 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
 94static 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
132static 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
141static const struct of_device_id mpfs_sys_controller_of_match[] = {
142	{.compatible = "microchip,mpfs-sys-controller", },
143	{},
144};
145MODULE_DEVICE_TABLE(of, mpfs_sys_controller_of_match);
146
147struct 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
174err_no_device:
175	dev_dbg(dev, "Parent device was not an MPFS system controller\n");
176	return ERR_PTR(-ENODEV);
177
178err_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}
182EXPORT_SYMBOL(mpfs_sys_controller_get);
183
184static 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};
192module_platform_driver(mpfs_sys_controller_driver);
193
194MODULE_LICENSE("GPL v2");
195MODULE_AUTHOR("Conor Dooley <conor.dooley@microchip.com>");
196MODULE_DESCRIPTION("MPFS system controller driver");