1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Copyright (C) 2015 ST Microelectronics
4 *
5 * Author: Lee Jones <lee.jones@linaro.org>
6 */
7
8#include <linux/debugfs.h>
9#include <linux/err.h>
10#include <linux/fs.h>
11#include <linux/io.h>
12#include <linux/kernel.h>
13#include <linux/mailbox_client.h>
14#include <linux/module.h>
15#include <linux/mutex.h>
16#include <linux/of.h>
17#include <linux/platform_device.h>
18#include <linux/poll.h>
19#include <linux/slab.h>
20#include <linux/spinlock.h>
21#include <linux/uaccess.h>
22#include <linux/sched/signal.h>
23
24#define MBOX_MAX_SIG_LEN	8
25#define MBOX_MAX_MSG_LEN	128
26#define MBOX_BYTES_PER_LINE	16
27#define MBOX_HEXDUMP_LINE_LEN	((MBOX_BYTES_PER_LINE * 4) + 2)
28#define MBOX_HEXDUMP_MAX_LEN	(MBOX_HEXDUMP_LINE_LEN *		\
29				 (MBOX_MAX_MSG_LEN / MBOX_BYTES_PER_LINE))
30
31static bool mbox_data_ready;
32
33struct mbox_test_device {
34	struct device		*dev;
35	void __iomem		*tx_mmio;
36	void __iomem		*rx_mmio;
37	struct mbox_chan	*tx_channel;
38	struct mbox_chan	*rx_channel;
39	char			*rx_buffer;
40	char			*signal;
41	char			*message;
42	spinlock_t		lock;
43	struct mutex		mutex;
44	wait_queue_head_t	waitq;
45	struct fasync_struct	*async_queue;
46	struct dentry		*root_debugfs_dir;
47};
48
49static ssize_t mbox_test_signal_write(struct file *filp,
50				       const char __user *userbuf,
51				       size_t count, loff_t *ppos)
52{
53	struct mbox_test_device *tdev = filp->private_data;
54
55	if (!tdev->tx_channel) {
56		dev_err(tdev->dev, "Channel cannot do Tx\n");
57		return -EINVAL;
58	}
59
60	if (count > MBOX_MAX_SIG_LEN) {
61		dev_err(tdev->dev,
62			"Signal length %zd greater than max allowed %d\n",
63			count, MBOX_MAX_SIG_LEN);
64		return -EINVAL;
65	}
66
67	/* Only allocate memory if we need to */
68	if (!tdev->signal) {
69		tdev->signal = kzalloc(MBOX_MAX_SIG_LEN, GFP_KERNEL);
70		if (!tdev->signal)
71			return -ENOMEM;
72	}
73
74	if (copy_from_user(tdev->signal, userbuf, count)) {
75		kfree(tdev->signal);
76		tdev->signal = NULL;
77		return -EFAULT;
78	}
79
80	return count;
81}
82
83static const struct file_operations mbox_test_signal_ops = {
84	.write	= mbox_test_signal_write,
85	.open	= simple_open,
86	.llseek	= generic_file_llseek,
87};
88
89static int mbox_test_message_fasync(int fd, struct file *filp, int on)
90{
91	struct mbox_test_device *tdev = filp->private_data;
92
93	return fasync_helper(fd, filp, on, &tdev->async_queue);
94}
95
96static ssize_t mbox_test_message_write(struct file *filp,
97				       const char __user *userbuf,
98				       size_t count, loff_t *ppos)
99{
100	struct mbox_test_device *tdev = filp->private_data;
101	char *message;
102	void *data;
103	int ret;
104
105	if (!tdev->tx_channel) {
106		dev_err(tdev->dev, "Channel cannot do Tx\n");
107		return -EINVAL;
108	}
109
110	if (count > MBOX_MAX_MSG_LEN) {
111		dev_err(tdev->dev,
112			"Message length %zd greater than max allowed %d\n",
113			count, MBOX_MAX_MSG_LEN);
114		return -EINVAL;
115	}
116
117	message = kzalloc(MBOX_MAX_MSG_LEN, GFP_KERNEL);
118	if (!message)
119		return -ENOMEM;
120
121	mutex_lock(&tdev->mutex);
122
123	tdev->message = message;
124	ret = copy_from_user(tdev->message, userbuf, count);
125	if (ret) {
126		ret = -EFAULT;
127		goto out;
128	}
129
130	/*
131	 * A separate signal is only of use if there is
132	 * MMIO to subsequently pass the message through
133	 */
134	if (tdev->tx_mmio && tdev->signal) {
135		print_hex_dump_bytes("Client: Sending: Signal: ", DUMP_PREFIX_ADDRESS,
136				     tdev->signal, MBOX_MAX_SIG_LEN);
137
138		data = tdev->signal;
139	} else
140		data = tdev->message;
141
142	print_hex_dump_bytes("Client: Sending: Message: ", DUMP_PREFIX_ADDRESS,
143			     tdev->message, MBOX_MAX_MSG_LEN);
144
145	ret = mbox_send_message(tdev->tx_channel, data);
146	if (ret < 0)
147		dev_err(tdev->dev, "Failed to send message via mailbox\n");
148
149out:
150	kfree(tdev->signal);
151	kfree(tdev->message);
152	tdev->signal = NULL;
153
154	mutex_unlock(&tdev->mutex);
155
156	return ret < 0 ? ret : count;
157}
158
159static bool mbox_test_message_data_ready(struct mbox_test_device *tdev)
160{
161	bool data_ready;
162	unsigned long flags;
163
164	spin_lock_irqsave(&tdev->lock, flags);
165	data_ready = mbox_data_ready;
166	spin_unlock_irqrestore(&tdev->lock, flags);
167
168	return data_ready;
169}
170
171static ssize_t mbox_test_message_read(struct file *filp, char __user *userbuf,
172				      size_t count, loff_t *ppos)
173{
174	struct mbox_test_device *tdev = filp->private_data;
175	unsigned long flags;
176	char *touser, *ptr;
177	int l = 0;
178	int ret;
179
180	DECLARE_WAITQUEUE(wait, current);
181
182	touser = kzalloc(MBOX_HEXDUMP_MAX_LEN + 1, GFP_KERNEL);
183	if (!touser)
184		return -ENOMEM;
185
186	if (!tdev->rx_channel) {
187		ret = snprintf(touser, 20, "<NO RX CAPABILITY>\n");
188		ret = simple_read_from_buffer(userbuf, count, ppos,
189					      touser, ret);
190		goto kfree_err;
191	}
192
193	add_wait_queue(&tdev->waitq, &wait);
194
195	do {
196		__set_current_state(TASK_INTERRUPTIBLE);
197
198		if (mbox_test_message_data_ready(tdev))
199			break;
200
201		if (filp->f_flags & O_NONBLOCK) {
202			ret = -EAGAIN;
203			goto waitq_err;
204		}
205
206		if (signal_pending(current)) {
207			ret = -ERESTARTSYS;
208			goto waitq_err;
209		}
210		schedule();
211
212	} while (1);
213
214	spin_lock_irqsave(&tdev->lock, flags);
215
216	ptr = tdev->rx_buffer;
217	while (l < MBOX_HEXDUMP_MAX_LEN) {
218		hex_dump_to_buffer(ptr,
219				   MBOX_BYTES_PER_LINE,
220				   MBOX_BYTES_PER_LINE, 1, touser + l,
221				   MBOX_HEXDUMP_LINE_LEN, true);
222
223		ptr += MBOX_BYTES_PER_LINE;
224		l += MBOX_HEXDUMP_LINE_LEN;
225		*(touser + (l - 1)) = '\n';
226	}
227	*(touser + l) = '\0';
228
229	memset(tdev->rx_buffer, 0, MBOX_MAX_MSG_LEN);
230	mbox_data_ready = false;
231
232	spin_unlock_irqrestore(&tdev->lock, flags);
233
234	ret = simple_read_from_buffer(userbuf, count, ppos, touser, MBOX_HEXDUMP_MAX_LEN);
235waitq_err:
236	__set_current_state(TASK_RUNNING);
237	remove_wait_queue(&tdev->waitq, &wait);
238kfree_err:
239	kfree(touser);
240	return ret;
241}
242
243static __poll_t
244mbox_test_message_poll(struct file *filp, struct poll_table_struct *wait)
245{
246	struct mbox_test_device *tdev = filp->private_data;
247
248	poll_wait(filp, &tdev->waitq, wait);
249
250	if (mbox_test_message_data_ready(tdev))
251		return EPOLLIN | EPOLLRDNORM;
252	return 0;
253}
254
255static const struct file_operations mbox_test_message_ops = {
256	.write	= mbox_test_message_write,
257	.read	= mbox_test_message_read,
258	.fasync	= mbox_test_message_fasync,
259	.poll	= mbox_test_message_poll,
260	.open	= simple_open,
261	.llseek	= generic_file_llseek,
262};
263
264static int mbox_test_add_debugfs(struct platform_device *pdev,
265				 struct mbox_test_device *tdev)
266{
267	if (!debugfs_initialized())
268		return 0;
269
270	tdev->root_debugfs_dir = debugfs_create_dir(dev_name(&pdev->dev), NULL);
271	if (!tdev->root_debugfs_dir) {
272		dev_err(&pdev->dev, "Failed to create Mailbox debugfs\n");
273		return -EINVAL;
274	}
275
276	debugfs_create_file("message", 0600, tdev->root_debugfs_dir,
277			    tdev, &mbox_test_message_ops);
278
279	debugfs_create_file("signal", 0200, tdev->root_debugfs_dir,
280			    tdev, &mbox_test_signal_ops);
281
282	return 0;
283}
284
285static void mbox_test_receive_message(struct mbox_client *client, void *message)
286{
287	struct mbox_test_device *tdev = dev_get_drvdata(client->dev);
288	unsigned long flags;
289
290	spin_lock_irqsave(&tdev->lock, flags);
291	if (tdev->rx_mmio) {
292		memcpy_fromio(tdev->rx_buffer, tdev->rx_mmio, MBOX_MAX_MSG_LEN);
293		print_hex_dump_bytes("Client: Received [MMIO]: ", DUMP_PREFIX_ADDRESS,
294				     tdev->rx_buffer, MBOX_MAX_MSG_LEN);
295	} else if (message) {
296		print_hex_dump_bytes("Client: Received [API]: ", DUMP_PREFIX_ADDRESS,
297				     message, MBOX_MAX_MSG_LEN);
298		memcpy(tdev->rx_buffer, message, MBOX_MAX_MSG_LEN);
299	}
300	mbox_data_ready = true;
301	spin_unlock_irqrestore(&tdev->lock, flags);
302
303	wake_up_interruptible(&tdev->waitq);
304
305	kill_fasync(&tdev->async_queue, SIGIO, POLL_IN);
306}
307
308static void mbox_test_prepare_message(struct mbox_client *client, void *message)
309{
310	struct mbox_test_device *tdev = dev_get_drvdata(client->dev);
311
312	if (tdev->tx_mmio) {
313		if (tdev->signal)
314			memcpy_toio(tdev->tx_mmio, tdev->message, MBOX_MAX_MSG_LEN);
315		else
316			memcpy_toio(tdev->tx_mmio, message, MBOX_MAX_MSG_LEN);
317	}
318}
319
320static void mbox_test_message_sent(struct mbox_client *client,
321				   void *message, int r)
322{
323	if (r)
324		dev_warn(client->dev,
325			 "Client: Message could not be sent: %d\n", r);
326	else
327		dev_info(client->dev,
328			 "Client: Message sent\n");
329}
330
331static struct mbox_chan *
332mbox_test_request_channel(struct platform_device *pdev, const char *name)
333{
334	struct mbox_client *client;
335	struct mbox_chan *channel;
336
337	client = devm_kzalloc(&pdev->dev, sizeof(*client), GFP_KERNEL);
338	if (!client)
339		return ERR_PTR(-ENOMEM);
340
341	client->dev		= &pdev->dev;
342	client->rx_callback	= mbox_test_receive_message;
343	client->tx_prepare	= mbox_test_prepare_message;
344	client->tx_done		= mbox_test_message_sent;
345	client->tx_block	= true;
346	client->knows_txdone	= false;
347	client->tx_tout		= 500;
348
349	channel = mbox_request_channel_byname(client, name);
350	if (IS_ERR(channel)) {
351		dev_warn(&pdev->dev, "Failed to request %s channel\n", name);
352		return NULL;
353	}
354
355	return channel;
356}
357
358static int mbox_test_probe(struct platform_device *pdev)
359{
360	struct mbox_test_device *tdev;
361	struct resource *res;
362	resource_size_t size;
363	int ret;
364
365	tdev = devm_kzalloc(&pdev->dev, sizeof(*tdev), GFP_KERNEL);
366	if (!tdev)
367		return -ENOMEM;
368
369	/* It's okay for MMIO to be NULL */
370	tdev->tx_mmio = devm_platform_get_and_ioremap_resource(pdev, 0, &res);
371	if (PTR_ERR(tdev->tx_mmio) == -EBUSY) {
372		/* if reserved area in SRAM, try just ioremap */
373		size = resource_size(res);
374		tdev->tx_mmio = devm_ioremap(&pdev->dev, res->start, size);
375	} else if (IS_ERR(tdev->tx_mmio)) {
376		tdev->tx_mmio = NULL;
377	}
378
379	/* If specified, second reg entry is Rx MMIO */
380	tdev->rx_mmio = devm_platform_get_and_ioremap_resource(pdev, 1, &res);
381	if (PTR_ERR(tdev->rx_mmio) == -EBUSY) {
382		size = resource_size(res);
383		tdev->rx_mmio = devm_ioremap(&pdev->dev, res->start, size);
384	} else if (IS_ERR(tdev->rx_mmio)) {
385		tdev->rx_mmio = tdev->tx_mmio;
386	}
387
388	tdev->tx_channel = mbox_test_request_channel(pdev, "tx");
389	tdev->rx_channel = mbox_test_request_channel(pdev, "rx");
390
391	if (IS_ERR_OR_NULL(tdev->tx_channel) && IS_ERR_OR_NULL(tdev->rx_channel))
392		return -EPROBE_DEFER;
393
394	/* If Rx is not specified but has Rx MMIO, then Rx = Tx */
395	if (!tdev->rx_channel && (tdev->rx_mmio != tdev->tx_mmio))
396		tdev->rx_channel = tdev->tx_channel;
397
398	tdev->dev = &pdev->dev;
399	platform_set_drvdata(pdev, tdev);
400
401	spin_lock_init(&tdev->lock);
402	mutex_init(&tdev->mutex);
403
404	if (tdev->rx_channel) {
405		tdev->rx_buffer = devm_kzalloc(&pdev->dev,
406					       MBOX_MAX_MSG_LEN, GFP_KERNEL);
407		if (!tdev->rx_buffer)
408			return -ENOMEM;
409	}
410
411	ret = mbox_test_add_debugfs(pdev, tdev);
412	if (ret)
413		return ret;
414
415	init_waitqueue_head(&tdev->waitq);
416	dev_info(&pdev->dev, "Successfully registered\n");
417
418	return 0;
419}
420
421static void mbox_test_remove(struct platform_device *pdev)
422{
423	struct mbox_test_device *tdev = platform_get_drvdata(pdev);
424
425	debugfs_remove_recursive(tdev->root_debugfs_dir);
426
427	if (tdev->tx_channel)
428		mbox_free_channel(tdev->tx_channel);
429	if (tdev->rx_channel)
430		mbox_free_channel(tdev->rx_channel);
431}
432
433static const struct of_device_id mbox_test_match[] = {
434	{ .compatible = "mailbox-test" },
435	{},
436};
437MODULE_DEVICE_TABLE(of, mbox_test_match);
438
439static struct platform_driver mbox_test_driver = {
440	.driver = {
441		.name = "mailbox_test",
442		.of_match_table = mbox_test_match,
443	},
444	.probe  = mbox_test_probe,
445	.remove_new = mbox_test_remove,
446};
447module_platform_driver(mbox_test_driver);
448
449MODULE_DESCRIPTION("Generic Mailbox Testing Facility");
450MODULE_AUTHOR("Lee Jones <lee.jones@linaro.org");
451MODULE_LICENSE("GPL v2");
452