mpfs-sys-controller.c

  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		ret = dev_err_probe(dev, PTR_ERR(sys_controller->flash), "Failed to get flash\n");
147		goto out_free;
148	}
149
150no_flash:
151	sys_controller->client.dev = dev;
152	sys_controller->client.rx_callback = mpfs_sys_controller_rx_callback;
153	sys_controller->client.tx_block = 1U;
154	sys_controller->client.tx_tout = msecs_to_jiffies(MPFS_SYS_CTRL_TIMEOUT_MS);
155
156	sys_controller->chan = mbox_request_channel(&sys_controller->client, 0);
157	if (IS_ERR(sys_controller->chan)) {
158		ret = dev_err_probe(dev, PTR_ERR(sys_controller->chan),
159				    "Failed to get mbox channel\n");
160		goto out_free;
161	}
162
163	init_completion(&sys_controller->c);
164	kref_init(&sys_controller->consumers);
165
166	platform_set_drvdata(pdev, sys_controller);
167
168
169	for (i = 0; i < ARRAY_SIZE(subdevs); i++) {
170		subdevs[i].dev.parent = dev;
171		if (platform_device_register(&subdevs[i]))
172			dev_warn(dev, "Error registering sub device %s\n", subdevs[i].name);
173	}
174
175	dev_info(&pdev->dev, "Registered MPFS system controller\n");
176
177	return 0;
178
179out_free:
180	kfree(sys_controller);
181	return ret;
182}
183
184static void mpfs_sys_controller_remove(struct platform_device *pdev)
185{
186	struct mpfs_sys_controller *sys_controller = platform_get_drvdata(pdev);
187
188	mpfs_sys_controller_put(sys_controller);
189}
190
191static const struct of_device_id mpfs_sys_controller_of_match[] = {
192	{.compatible = "microchip,mpfs-sys-controller", },
193	{},
194};
195MODULE_DEVICE_TABLE(of, mpfs_sys_controller_of_match);
196
197struct mpfs_sys_controller *mpfs_sys_controller_get(struct device *dev)
198{
199	const struct of_device_id *match;
200	struct mpfs_sys_controller *sys_controller;
201	int ret;
202
203	if (!dev->parent)
204		goto err_no_device;
205
206	match = of_match_node(mpfs_sys_controller_of_match,  dev->parent->of_node);
207	of_node_put(dev->parent->of_node);
208	if (!match)
209		goto err_no_device;
210
211	sys_controller = dev_get_drvdata(dev->parent);
212	if (!sys_controller)
213		goto err_bad_device;
214
215	if (!kref_get_unless_zero(&sys_controller->consumers))
216		goto err_bad_device;
217
218	ret = devm_add_action_or_reset(dev, mpfs_sys_controller_put, sys_controller);
219	if (ret)
220		return ERR_PTR(ret);
221
222	return sys_controller;
223
224err_no_device:
225	dev_dbg(dev, "Parent device was not an MPFS system controller\n");
226	return ERR_PTR(-ENODEV);
227
228err_bad_device:
229	dev_dbg(dev, "MPFS system controller found but could not register as a sub device\n");
230	return ERR_PTR(-EPROBE_DEFER);
231}
232EXPORT_SYMBOL(mpfs_sys_controller_get);
233
234static struct platform_driver mpfs_sys_controller_driver = {
235	.driver = {
236		.name = "mpfs-sys-controller",
237		.of_match_table = mpfs_sys_controller_of_match,
238	},
239	.probe = mpfs_sys_controller_probe,
240	.remove = mpfs_sys_controller_remove,
241};
242module_platform_driver(mpfs_sys_controller_driver);
243
244MODULE_LICENSE("GPL v2");
245MODULE_AUTHOR("Conor Dooley <conor.dooley@microchip.com>");
246MODULE_DESCRIPTION("MPFS system controller driver");