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/jiffies.h>
 15#include <linux/mtd/mtd.h>
 16#include <linux/spi/spi.h>
 17#include <linux/interrupt.h>
 18#include <linux/of.h>
 19#include <linux/mailbox_client.h>
 20#include <linux/platform_device.h>
 21#include <soc/microchip/mpfs.h>
 22
 23/*
 24 * This timeout must be long, as some services (example: image authentication)
 25 * take significant time to complete
 26 */
 27#define MPFS_SYS_CTRL_TIMEOUT_MS 30000
 28
 29static DEFINE_MUTEX(transaction_lock);
 30
 31struct mpfs_sys_controller {
 32	struct mbox_client client;
 33	struct mbox_chan *chan;
 34	struct completion c;
 35	struct mtd_info *flash;
 36	struct kref consumers;
 37};
 38
 39int mpfs_blocking_transaction(struct mpfs_sys_controller *sys_controller, struct mpfs_mss_msg *msg)
 40{
 41	unsigned long timeout = msecs_to_jiffies(MPFS_SYS_CTRL_TIMEOUT_MS);
 42	int ret;
 43
 44	ret = mutex_lock_interruptible(&transaction_lock);
 45	if (ret)
 46		return ret;
 47
 48	reinit_completion(&sys_controller->c);
 49
 50	ret = mbox_send_message(sys_controller->chan, msg);
 51	if (ret < 0) {
 52		dev_warn(sys_controller->client.dev, "MPFS sys controller service timeout\n");
 53		goto out;
 54	}
 55
 56	/*
 57	 * Unfortunately, the system controller will only deliver an interrupt
 58	 * if a service succeeds. mbox_send_message() will block until the busy
 59	 * flag is gone. If the busy flag is gone but no interrupt has arrived
 60	 * to trigger the rx callback then the service can be deemed to have
 61	 * failed.
 62	 * The caller can then interrogate msg::response::resp_status to
 63	 * determine the cause of the failure.
 64	 * mbox_send_message() returns positive integers in the success path, so
 65	 * ret needs to be cleared if we do get an interrupt.
 66	 */
 67	if (!wait_for_completion_timeout(&sys_controller->c, timeout)) {
 68		ret = -EBADMSG;
 69		dev_warn(sys_controller->client.dev,
 70			 "MPFS sys controller service failed with status: %d\n",
 71			 msg->response->resp_status);
 72	} else {
 73		ret = 0;
 74	}
 75
 76out:
 77	mutex_unlock(&transaction_lock);
 78
 79	return ret;
 80}
 81EXPORT_SYMBOL(mpfs_blocking_transaction);
 82
 83static void mpfs_sys_controller_rx_callback(struct mbox_client *client, void *msg)
 84{
 85	struct mpfs_sys_controller *sys_controller =
 86		container_of(client, struct mpfs_sys_controller, client);
 87
 88	complete(&sys_controller->c);
 89}
 90
 91static void mpfs_sys_controller_delete(struct kref *kref)
 92{
 93	struct mpfs_sys_controller *sys_controller =
 94		container_of(kref, struct mpfs_sys_controller, consumers);
 95
 96	mbox_free_channel(sys_controller->chan);
 97	kfree(sys_controller);
 98}
 99
100static void mpfs_sys_controller_put(void *data)
101{
102	struct mpfs_sys_controller *sys_controller = data;
103
104	kref_put(&sys_controller->consumers, mpfs_sys_controller_delete);
105}
106
107struct mtd_info *mpfs_sys_controller_get_flash(struct mpfs_sys_controller *mpfs_client)
108{
109	return mpfs_client->flash;
110}
111EXPORT_SYMBOL(mpfs_sys_controller_get_flash);
112
113static struct platform_device subdevs[] = {
114	{
115		.name		= "mpfs-rng",
116		.id		= -1,
117	},
118	{
119		.name		= "mpfs-generic-service",
120		.id		= -1,
121	},
122	{
123		.name		= "mpfs-auto-update",
124		.id		= -1,
125	},
126};
127
128static int mpfs_sys_controller_probe(struct platform_device *pdev)
129{
130	struct device *dev = &pdev->dev;
131	struct mpfs_sys_controller *sys_controller;
132	struct device_node *np;
133	int i, ret;
134
135	sys_controller = kzalloc(sizeof(*sys_controller), GFP_KERNEL);
136	if (!sys_controller)
137		return -ENOMEM;
138
139	np = of_parse_phandle(dev->of_node, "microchip,bitstream-flash", 0);
140	if (!np)
141		goto no_flash;
142
143	sys_controller->flash = of_get_mtd_device_by_node(np);
144	of_node_put(np);
145	if (IS_ERR(sys_controller->flash))
146		return dev_err_probe(dev, PTR_ERR(sys_controller->flash), "Failed to get flash\n");
147
148no_flash:
149	sys_controller->client.dev = dev;
150	sys_controller->client.rx_callback = mpfs_sys_controller_rx_callback;
151	sys_controller->client.tx_block = 1U;
152	sys_controller->client.tx_tout = msecs_to_jiffies(MPFS_SYS_CTRL_TIMEOUT_MS);
153
154	sys_controller->chan = mbox_request_channel(&sys_controller->client, 0);
155	if (IS_ERR(sys_controller->chan)) {
156		ret = dev_err_probe(dev, PTR_ERR(sys_controller->chan),
157				    "Failed to get mbox channel\n");
158		kfree(sys_controller);
159		return ret;
160	}
161
162	init_completion(&sys_controller->c);
163	kref_init(&sys_controller->consumers);
164
165	platform_set_drvdata(pdev, sys_controller);
166
167
168	for (i = 0; i < ARRAY_SIZE(subdevs); i++) {
169		subdevs[i].dev.parent = dev;
170		if (platform_device_register(&subdevs[i]))
171			dev_warn(dev, "Error registering sub device %s\n", subdevs[i].name);
172	}
173
174	dev_info(&pdev->dev, "Registered MPFS system controller\n");
175
176	return 0;
177}
178
179static void mpfs_sys_controller_remove(struct platform_device *pdev)
180{
181	struct mpfs_sys_controller *sys_controller = platform_get_drvdata(pdev);
182
183	mpfs_sys_controller_put(sys_controller);
184}
185
186static const struct of_device_id mpfs_sys_controller_of_match[] = {
187	{.compatible = "microchip,mpfs-sys-controller", },
188	{},
189};
190MODULE_DEVICE_TABLE(of, mpfs_sys_controller_of_match);
191
192struct mpfs_sys_controller *mpfs_sys_controller_get(struct device *dev)
193{
194	const struct of_device_id *match;
195	struct mpfs_sys_controller *sys_controller;
196	int ret;
197
198	if (!dev->parent)
199		goto err_no_device;
200
201	match = of_match_node(mpfs_sys_controller_of_match,  dev->parent->of_node);
202	of_node_put(dev->parent->of_node);
203	if (!match)
204		goto err_no_device;
205
206	sys_controller = dev_get_drvdata(dev->parent);
207	if (!sys_controller)
208		goto err_bad_device;
209
210	if (!kref_get_unless_zero(&sys_controller->consumers))
211		goto err_bad_device;
212
213	ret = devm_add_action_or_reset(dev, mpfs_sys_controller_put, sys_controller);
214	if (ret)
215		return ERR_PTR(ret);
216
217	return sys_controller;
218
219err_no_device:
220	dev_dbg(dev, "Parent device was not an MPFS system controller\n");
221	return ERR_PTR(-ENODEV);
222
223err_bad_device:
224	dev_dbg(dev, "MPFS system controller found but could not register as a sub device\n");
225	return ERR_PTR(-EPROBE_DEFER);
226}
227EXPORT_SYMBOL(mpfs_sys_controller_get);
228
229static struct platform_driver mpfs_sys_controller_driver = {
230	.driver = {
231		.name = "mpfs-sys-controller",
232		.of_match_table = mpfs_sys_controller_of_match,
233	},
234	.probe = mpfs_sys_controller_probe,
235	.remove_new = mpfs_sys_controller_remove,
236};
237module_platform_driver(mpfs_sys_controller_driver);
238
239MODULE_LICENSE("GPL v2");
240MODULE_AUTHOR("Conor Dooley <conor.dooley@microchip.com>");
241MODULE_DESCRIPTION("MPFS system controller driver");