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
mbox_test_signal_write(struct file * filp,const char __user * userbuf,size_t count,loff_t * ppos)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
mbox_test_message_fasync(int fd,struct file * filp,int on)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
mbox_test_message_write(struct file * filp,const char __user * userbuf,size_t count,loff_t * ppos)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
mbox_test_message_data_ready(struct mbox_test_device * tdev)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
mbox_test_message_read(struct file * filp,char __user * userbuf,size_t count,loff_t * ppos)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 __poll_t
mbox_test_message_poll(struct file * filp,struct poll_table_struct * wait)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 EPOLLIN | EPOLLRDNORM;
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
mbox_test_add_debugfs(struct platform_device * pdev,struct mbox_test_device * tdev)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
mbox_test_receive_message(struct mbox_client * client,void * message)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
mbox_test_prepare_message(struct mbox_client * client,void * message)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
mbox_test_message_sent(struct mbox_client * client,void * message,int r)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 *
mbox_test_request_channel(struct platform_device * pdev,const char * name)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
mbox_test_probe(struct platform_device * pdev)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
mbox_test_remove(struct platform_device * pdev)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
