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/io.h>
15 #include <linux/kernel.h>
16 #include <linux/mailbox_client.h>
17 #include <linux/module.h>
18 #include <linux/of.h>
19 #include <linux/platform_device.h>
20 #include <linux/slab.h>
21 #include <linux/uaccess.h>
22 
23 #define MBOX_MAX_SIG_LEN	8
24 #define MBOX_MAX_MSG_LEN	128
25 #define MBOX_BYTES_PER_LINE	16
26 #define MBOX_HEXDUMP_LINE_LEN	((MBOX_BYTES_PER_LINE * 4) + 2)
27 #define MBOX_HEXDUMP_MAX_LEN	(MBOX_HEXDUMP_LINE_LEN *		\
28 				 (MBOX_MAX_MSG_LEN / MBOX_BYTES_PER_LINE))
29 
30 static struct dentry *root_debugfs_dir;
31 
32 struct mbox_test_device {
33 	struct device		*dev;
34 	void __iomem		*tx_mmio;
35 	void __iomem		*rx_mmio;
36 	struct mbox_chan	*tx_channel;
37 	struct mbox_chan	*rx_channel;
38 	char			*rx_buffer;
39 	char			*signal;
40 	char			*message;
41 	spinlock_t		lock;
42 };
43 
44 static ssize_t mbox_test_signal_write(struct file *filp,
45 				       const char __user *userbuf,
46 				       size_t count, loff_t *ppos)
47 {
48 	struct mbox_test_device *tdev = filp->private_data;
49 
50 	if (!tdev->tx_channel) {
51 		dev_err(tdev->dev, "Channel cannot do Tx\n");
52 		return -EINVAL;
53 	}
54 
55 	if (count > MBOX_MAX_SIG_LEN) {
56 		dev_err(tdev->dev,
57 			"Signal length %zd greater than max allowed %d\n",
58 			count, MBOX_MAX_SIG_LEN);
59 		return -EINVAL;
60 	}
61 
62 	/* Only allocate memory if we need to */
63 	if (!tdev->signal) {
64 		tdev->signal = kzalloc(MBOX_MAX_SIG_LEN, GFP_KERNEL);
65 		if (!tdev->signal)
66 			return -ENOMEM;
67 	}
68 
69 	if (copy_from_user(tdev->signal, userbuf, count)) {
70 		kfree(tdev->signal);
71 		tdev->signal = NULL;
72 		return -EFAULT;
73 	}
74 
75 	return count;
76 }
77 
78 static const struct file_operations mbox_test_signal_ops = {
79 	.write	= mbox_test_signal_write,
80 	.open	= simple_open,
81 	.llseek	= generic_file_llseek,
82 };
83 
84 static ssize_t mbox_test_message_write(struct file *filp,
85 				       const char __user *userbuf,
86 				       size_t count, loff_t *ppos)
87 {
88 	struct mbox_test_device *tdev = filp->private_data;
89 	void *data;
90 	int ret;
91 
92 	if (!tdev->tx_channel) {
93 		dev_err(tdev->dev, "Channel cannot do Tx\n");
94 		return -EINVAL;
95 	}
96 
97 	if (count > MBOX_MAX_MSG_LEN) {
98 		dev_err(tdev->dev,
99 			"Message length %zd greater than max allowed %d\n",
100 			count, MBOX_MAX_MSG_LEN);
101 		return -EINVAL;
102 	}
103 
104 	tdev->message = kzalloc(MBOX_MAX_MSG_LEN, GFP_KERNEL);
105 	if (!tdev->message)
106 		return -ENOMEM;
107 
108 	ret = copy_from_user(tdev->message, userbuf, count);
109 	if (ret) {
110 		ret = -EFAULT;
111 		goto out;
112 	}
113 
114 	/*
115 	 * A separate signal is only of use if there is
116 	 * MMIO to subsequently pass the message through
117 	 */
118 	if (tdev->tx_mmio && tdev->signal) {
119 		print_hex_dump_bytes("Client: Sending: Signal: ", DUMP_PREFIX_ADDRESS,
120 				     tdev->signal, MBOX_MAX_SIG_LEN);
121 
122 		data = tdev->signal;
123 	} else
124 		data = tdev->message;
125 
126 	print_hex_dump_bytes("Client: Sending: Message: ", DUMP_PREFIX_ADDRESS,
127 			     tdev->message, MBOX_MAX_MSG_LEN);
128 
129 	ret = mbox_send_message(tdev->tx_channel, data);
130 	if (ret < 0)
131 		dev_err(tdev->dev, "Failed to send message via mailbox\n");
132 
133 out:
134 	kfree(tdev->signal);
135 	kfree(tdev->message);
136 
137 	return ret < 0 ? ret : count;
138 }
139 
140 static ssize_t mbox_test_message_read(struct file *filp, char __user *userbuf,
141 				      size_t count, loff_t *ppos)
142 {
143 	struct mbox_test_device *tdev = filp->private_data;
144 	unsigned long flags;
145 	char *touser, *ptr;
146 	int l = 0;
147 	int ret;
148 
149 	touser = kzalloc(MBOX_HEXDUMP_MAX_LEN + 1, GFP_KERNEL);
150 	if (!touser)
151 		return -ENOMEM;
152 
153 	if (!tdev->rx_channel) {
154 		ret = snprintf(touser, 20, "<NO RX CAPABILITY>\n");
155 		ret = simple_read_from_buffer(userbuf, count, ppos,
156 					      touser, ret);
157 		goto out;
158 	}
159 
160 	if (tdev->rx_buffer[0] == '\0') {
161 		ret = snprintf(touser, 9, "<EMPTY>\n");
162 		ret = simple_read_from_buffer(userbuf, count, ppos,
163 					      touser, ret);
164 		goto out;
165 	}
166 
167 	spin_lock_irqsave(&tdev->lock, flags);
168 
169 	ptr = tdev->rx_buffer;
170 	while (l < MBOX_HEXDUMP_MAX_LEN) {
171 		hex_dump_to_buffer(ptr,
172 				   MBOX_BYTES_PER_LINE,
173 				   MBOX_BYTES_PER_LINE, 1, touser + l,
174 				   MBOX_HEXDUMP_LINE_LEN, true);
175 
176 		ptr += MBOX_BYTES_PER_LINE;
177 		l += MBOX_HEXDUMP_LINE_LEN;
178 		*(touser + (l - 1)) = '\n';
179 	}
180 	*(touser + l) = '\0';
181 
182 	memset(tdev->rx_buffer, 0, MBOX_MAX_MSG_LEN);
183 
184 	spin_unlock_irqrestore(&tdev->lock, flags);
185 
186 	ret = simple_read_from_buffer(userbuf, count, ppos, touser, MBOX_HEXDUMP_MAX_LEN);
187 out:
188 	kfree(touser);
189 	return ret;
190 }
191 
192 static const struct file_operations mbox_test_message_ops = {
193 	.write	= mbox_test_message_write,
194 	.read	= mbox_test_message_read,
195 	.open	= simple_open,
196 	.llseek	= generic_file_llseek,
197 };
198 
199 static int mbox_test_add_debugfs(struct platform_device *pdev,
200 				 struct mbox_test_device *tdev)
201 {
202 	if (!debugfs_initialized())
203 		return 0;
204 
205 	root_debugfs_dir = debugfs_create_dir("mailbox", NULL);
206 	if (!root_debugfs_dir) {
207 		dev_err(&pdev->dev, "Failed to create Mailbox debugfs\n");
208 		return -EINVAL;
209 	}
210 
211 	debugfs_create_file("message", 0600, root_debugfs_dir,
212 			    tdev, &mbox_test_message_ops);
213 
214 	debugfs_create_file("signal", 0200, root_debugfs_dir,
215 			    tdev, &mbox_test_signal_ops);
216 
217 	return 0;
218 }
219 
220 static void mbox_test_receive_message(struct mbox_client *client, void *message)
221 {
222 	struct mbox_test_device *tdev = dev_get_drvdata(client->dev);
223 	unsigned long flags;
224 
225 	spin_lock_irqsave(&tdev->lock, flags);
226 	if (tdev->rx_mmio) {
227 		memcpy_fromio(tdev->rx_buffer, tdev->rx_mmio, MBOX_MAX_MSG_LEN);
228 		print_hex_dump_bytes("Client: Received [MMIO]: ", DUMP_PREFIX_ADDRESS,
229 				     tdev->rx_buffer, MBOX_MAX_MSG_LEN);
230 	} else if (message) {
231 		print_hex_dump_bytes("Client: Received [API]: ", DUMP_PREFIX_ADDRESS,
232 				     message, MBOX_MAX_MSG_LEN);
233 		memcpy(tdev->rx_buffer, message, MBOX_MAX_MSG_LEN);
234 	}
235 	spin_unlock_irqrestore(&tdev->lock, flags);
236 }
237 
238 static void mbox_test_prepare_message(struct mbox_client *client, void *message)
239 {
240 	struct mbox_test_device *tdev = dev_get_drvdata(client->dev);
241 
242 	if (tdev->tx_mmio) {
243 		if (tdev->signal)
244 			memcpy_toio(tdev->tx_mmio, tdev->message, MBOX_MAX_MSG_LEN);
245 		else
246 			memcpy_toio(tdev->tx_mmio, message, MBOX_MAX_MSG_LEN);
247 	}
248 }
249 
250 static void mbox_test_message_sent(struct mbox_client *client,
251 				   void *message, int r)
252 {
253 	if (r)
254 		dev_warn(client->dev,
255 			 "Client: Message could not be sent: %d\n", r);
256 	else
257 		dev_info(client->dev,
258 			 "Client: Message sent\n");
259 }
260 
261 static struct mbox_chan *
262 mbox_test_request_channel(struct platform_device *pdev, const char *name)
263 {
264 	struct mbox_client *client;
265 	struct mbox_chan *channel;
266 
267 	client = devm_kzalloc(&pdev->dev, sizeof(*client), GFP_KERNEL);
268 	if (!client)
269 		return ERR_PTR(-ENOMEM);
270 
271 	client->dev		= &pdev->dev;
272 	client->rx_callback	= mbox_test_receive_message;
273 	client->tx_prepare	= mbox_test_prepare_message;
274 	client->tx_done		= mbox_test_message_sent;
275 	client->tx_block	= true;
276 	client->knows_txdone	= false;
277 	client->tx_tout		= 500;
278 
279 	channel = mbox_request_channel_byname(client, name);
280 	if (IS_ERR(channel)) {
281 		dev_warn(&pdev->dev, "Failed to request %s channel\n", name);
282 		return NULL;
283 	}
284 
285 	return channel;
286 }
287 
288 static int mbox_test_probe(struct platform_device *pdev)
289 {
290 	struct mbox_test_device *tdev;
291 	struct resource *res;
292 	int ret;
293 
294 	tdev = devm_kzalloc(&pdev->dev, sizeof(*tdev), GFP_KERNEL);
295 	if (!tdev)
296 		return -ENOMEM;
297 
298 	/* It's okay for MMIO to be NULL */
299 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
300 	tdev->tx_mmio = devm_ioremap_resource(&pdev->dev, res);
301 	if (IS_ERR(tdev->tx_mmio))
302 		tdev->tx_mmio = NULL;
303 
304 	/* If specified, second reg entry is Rx MMIO */
305 	res = platform_get_resource(pdev, IORESOURCE_MEM, 1);
306 	tdev->rx_mmio = devm_ioremap_resource(&pdev->dev, res);
307 	if (IS_ERR(tdev->rx_mmio))
308 		tdev->rx_mmio = tdev->tx_mmio;
309 
310 	tdev->tx_channel = mbox_test_request_channel(pdev, "tx");
311 	tdev->rx_channel = mbox_test_request_channel(pdev, "rx");
312 
313 	if (!tdev->tx_channel && !tdev->rx_channel)
314 		return -EPROBE_DEFER;
315 
316 	/* If Rx is not specified but has Rx MMIO, then Rx = Tx */
317 	if (!tdev->rx_channel && (tdev->rx_mmio != tdev->tx_mmio))
318 		tdev->rx_channel = tdev->tx_channel;
319 
320 	tdev->dev = &pdev->dev;
321 	platform_set_drvdata(pdev, tdev);
322 
323 	spin_lock_init(&tdev->lock);
324 
325 	if (tdev->rx_channel) {
326 		tdev->rx_buffer = devm_kzalloc(&pdev->dev,
327 					       MBOX_MAX_MSG_LEN, GFP_KERNEL);
328 		if (!tdev->rx_buffer)
329 			return -ENOMEM;
330 	}
331 
332 	ret = mbox_test_add_debugfs(pdev, tdev);
333 	if (ret)
334 		return ret;
335 
336 	dev_info(&pdev->dev, "Successfully registered\n");
337 
338 	return 0;
339 }
340 
341 static int mbox_test_remove(struct platform_device *pdev)
342 {
343 	struct mbox_test_device *tdev = platform_get_drvdata(pdev);
344 
345 	debugfs_remove_recursive(root_debugfs_dir);
346 
347 	if (tdev->tx_channel)
348 		mbox_free_channel(tdev->tx_channel);
349 	if (tdev->rx_channel)
350 		mbox_free_channel(tdev->rx_channel);
351 
352 	return 0;
353 }
354 
355 static const struct of_device_id mbox_test_match[] = {
356 	{ .compatible = "mailbox-test" },
357 	{},
358 };
359 
360 static struct platform_driver mbox_test_driver = {
361 	.driver = {
362 		.name = "mailbox_test",
363 		.of_match_table = mbox_test_match,
364 	},
365 	.probe  = mbox_test_probe,
366 	.remove = mbox_test_remove,
367 };
368 module_platform_driver(mbox_test_driver);
369 
370 MODULE_DESCRIPTION("Generic Mailbox Testing Facility");
371 MODULE_AUTHOR("Lee Jones <lee.jones@linaro.org");
372 MODULE_LICENSE("GPL v2");
373