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