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