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1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Copyright (C) 2015 ST Microelectronics
4 *
5 * Author: Lee Jones <[email protected]>
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
31struct 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 struct mutex mutex;
42 wait_queue_head_t waitq;
43 bool data_ready;
44 struct fasync_struct *async_queue;
45 struct dentry *root_debugfs_dir;
46};
47
48static ssize_t mbox_test_signal_write(struct file *filp,
49 const char __user *userbuf,
50 size_t count, loff_t *ppos)
51{
52 struct mbox_test_device *tdev = filp->private_data;
53
54 if (!tdev->tx_channel) {
55 dev_err(tdev->dev, "Channel cannot do Tx\n");
56 return -EINVAL;
57 }
58
59 if (count > MBOX_MAX_SIG_LEN) {
60 dev_err(tdev->dev,
61 "Signal length %zd greater than max allowed %d\n",
62 count, MBOX_MAX_SIG_LEN);
63 return -EINVAL;
64 }
65
66 /* Only allocate memory if we need to */
67 if (!tdev->signal) {
68 tdev->signal = kzalloc(MBOX_MAX_SIG_LEN, GFP_KERNEL);
69 if (!tdev->signal)
70 return -ENOMEM;
71 }
72
73 if (copy_from_user(tdev->signal, userbuf, count)) {
74 kfree(tdev->signal);
75 tdev->signal = NULL;
76 return -EFAULT;
77 }
78
79 return count;
80}
81
82static const struct file_operations mbox_test_signal_ops = {
83 .write = mbox_test_signal_write,
84 .open = simple_open,
85 .llseek = generic_file_llseek,
86};
87
88static int mbox_test_message_fasync(int fd, struct file *filp, int on)
89{
90 struct mbox_test_device *tdev = filp->private_data;
91
92 return fasync_helper(fd, filp, on, &tdev->async_queue);
93}
94
95static ssize_t mbox_test_message_write(struct file *filp,
96 const char __user *userbuf,
97 size_t count, loff_t *ppos)
98{
99 struct mbox_test_device *tdev = filp->private_data;
100 char *message;
101 void *data;
102 int ret;
103
104 if (!tdev->tx_channel) {
105 dev_err(tdev->dev, "Channel cannot do Tx\n");
106 return -EINVAL;
107 }
108
109 if (count > MBOX_MAX_MSG_LEN) {
110 dev_err(tdev->dev,
111 "Message length %zd greater than max allowed %d\n",
112 count, MBOX_MAX_MSG_LEN);
113 return -EINVAL;
114 }
115
116 message = kzalloc(MBOX_MAX_MSG_LEN, GFP_KERNEL);
117 if (!message)
118 return -ENOMEM;
119
120 mutex_lock(&tdev->mutex);
121
122 tdev->message = message;
123 ret = copy_from_user(tdev->message, userbuf, count);
124 if (ret) {
125 ret = -EFAULT;
126 goto out;
127 }
128
129 /*
130 * A separate signal is only of use if there is
131 * MMIO to subsequently pass the message through
132 */
133 if (tdev->tx_mmio && tdev->signal) {
134 print_hex_dump_bytes("Client: Sending: Signal: ", DUMP_PREFIX_ADDRESS,
135 tdev->signal, MBOX_MAX_SIG_LEN);
136
137 data = tdev->signal;
138 } else
139 data = tdev->message;
140
141 print_hex_dump_bytes("Client: Sending: Message: ", DUMP_PREFIX_ADDRESS,
142 tdev->message, MBOX_MAX_MSG_LEN);
143
144 ret = mbox_send_message(tdev->tx_channel, data);
145 if (ret < 0)
146 dev_err(tdev->dev, "Failed to send message via mailbox\n");
147
148out:
149 kfree(tdev->signal);
150 kfree(tdev->message);
151 tdev->signal = NULL;
152
153 mutex_unlock(&tdev->mutex);
154
155 return ret < 0 ? ret : count;
156}
157
158static bool mbox_test_message_data_ready(struct mbox_test_device *tdev)
159{
160 bool data_ready;
161 unsigned long flags;
162
163 spin_lock_irqsave(&tdev->lock, flags);
164 data_ready = tdev->data_ready;
165 spin_unlock_irqrestore(&tdev->lock, flags);
166
167 return data_ready;
168}
169
170static ssize_t mbox_test_message_read(struct file *filp, char __user *userbuf,
171 size_t count, loff_t *ppos)
172{
173 struct mbox_test_device *tdev = filp->private_data;
174 unsigned long flags;
175 char *touser, *ptr;
176 int l = 0;
177 int ret;
178
179 DECLARE_WAITQUEUE(wait, current);
180
181 touser = kzalloc(MBOX_HEXDUMP_MAX_LEN + 1, GFP_KERNEL);
182 if (!touser)
183 return -ENOMEM;
184
185 if (!tdev->rx_channel) {
186 ret = snprintf(touser, 20, "<NO RX CAPABILITY>\n");
187 ret = simple_read_from_buffer(userbuf, count, ppos,
188 touser, ret);
189 goto kfree_err;
190 }
191
192 add_wait_queue(&tdev->waitq, &wait);
193
194 do {
195 __set_current_state(TASK_INTERRUPTIBLE);
196
197 if (mbox_test_message_data_ready(tdev))
198 break;
199
200 if (filp->f_flags & O_NONBLOCK) {
201 ret = -EAGAIN;
202 goto waitq_err;
203 }
204
205 if (signal_pending(current)) {
206 ret = -ERESTARTSYS;
207 goto waitq_err;
208 }
209 schedule();
210
211 } while (1);
212
213 spin_lock_irqsave(&tdev->lock, flags);
214
215 ptr = tdev->rx_buffer;
216 while (l < MBOX_HEXDUMP_MAX_LEN) {
217 hex_dump_to_buffer(ptr,
218 MBOX_BYTES_PER_LINE,
219 MBOX_BYTES_PER_LINE, 1, touser + l,
220 MBOX_HEXDUMP_LINE_LEN, true);
221
222 ptr += MBOX_BYTES_PER_LINE;
223 l += MBOX_HEXDUMP_LINE_LEN;
224 *(touser + (l - 1)) = '\n';
225 }
226 *(touser + l) = '\0';
227
228 memset(tdev->rx_buffer, 0, MBOX_MAX_MSG_LEN);
229 tdev->data_ready = false;
230
231 spin_unlock_irqrestore(&tdev->lock, flags);
232
233 ret = simple_read_from_buffer(userbuf, count, ppos, touser, MBOX_HEXDUMP_MAX_LEN);
234waitq_err:
235 __set_current_state(TASK_RUNNING);
236 remove_wait_queue(&tdev->waitq, &wait);
237kfree_err:
238 kfree(touser);
239 return ret;
240}
241
242static __poll_t
243mbox_test_message_poll(struct file *filp, struct poll_table_struct *wait)
244{
245 struct mbox_test_device *tdev = filp->private_data;
246
247 poll_wait(filp, &tdev->waitq, wait);
248
249 if (mbox_test_message_data_ready(tdev))
250 return EPOLLIN | EPOLLRDNORM;
251 return 0;
252}
253
254static const struct file_operations mbox_test_message_ops = {
255 .write = mbox_test_message_write,
256 .read = mbox_test_message_read,
257 .fasync = mbox_test_message_fasync,
258 .poll = mbox_test_message_poll,
259 .open = simple_open,
260 .llseek = generic_file_llseek,
261};
262
263static int mbox_test_add_debugfs(struct platform_device *pdev,
264 struct mbox_test_device *tdev)
265{
266 if (!debugfs_initialized())
267 return 0;
268
269 tdev->root_debugfs_dir = debugfs_create_dir(dev_name(&pdev->dev), NULL);
270 if (IS_ERR(tdev->root_debugfs_dir)) {
271 dev_err(&pdev->dev, "Failed to create Mailbox debugfs\n");
272 return -EINVAL;
273 }
274
275 debugfs_create_file("message", 0600, tdev->root_debugfs_dir,
276 tdev, &mbox_test_message_ops);
277
278 debugfs_create_file("signal", 0200, tdev->root_debugfs_dir,
279 tdev, &mbox_test_signal_ops);
280
281 return 0;
282}
283
284static void mbox_test_receive_message(struct mbox_client *client, void *message)
285{
286 struct mbox_test_device *tdev = dev_get_drvdata(client->dev);
287 unsigned long flags;
288
289 spin_lock_irqsave(&tdev->lock, flags);
290 if (tdev->rx_mmio) {
291 memcpy_fromio(tdev->rx_buffer, tdev->rx_mmio, MBOX_MAX_MSG_LEN);
292 print_hex_dump_bytes("Client: Received [MMIO]: ", DUMP_PREFIX_ADDRESS,
293 tdev->rx_buffer, MBOX_MAX_MSG_LEN);
294 } else if (message) {
295 print_hex_dump_bytes("Client: Received [API]: ", DUMP_PREFIX_ADDRESS,
296 message, MBOX_MAX_MSG_LEN);
297 memcpy(tdev->rx_buffer, message, MBOX_MAX_MSG_LEN);
298 }
299 tdev->data_ready = true;
300 spin_unlock_irqrestore(&tdev->lock, flags);
301
302 wake_up_interruptible(&tdev->waitq);
303
304 kill_fasync(&tdev->async_queue, SIGIO, POLL_IN);
305}
306
307static void mbox_test_prepare_message(struct mbox_client *client, void *message)
308{
309 struct mbox_test_device *tdev = dev_get_drvdata(client->dev);
310
311 if (tdev->tx_mmio) {
312 if (tdev->signal)
313 memcpy_toio(tdev->tx_mmio, tdev->message, MBOX_MAX_MSG_LEN);
314 else
315 memcpy_toio(tdev->tx_mmio, message, MBOX_MAX_MSG_LEN);
316 }
317}
318
319static void mbox_test_message_sent(struct mbox_client *client,
320 void *message, int r)
321{
322 if (r)
323 dev_warn(client->dev,
324 "Client: Message could not be sent: %d\n", r);
325 else
326 dev_info(client->dev,
327 "Client: Message sent\n");
328}
329
330static struct mbox_chan *
331mbox_test_request_channel(struct platform_device *pdev, const char *name)
332{
333 struct mbox_client *client;
334 struct mbox_chan *channel;
335
336 client = devm_kzalloc(&pdev->dev, sizeof(*client), GFP_KERNEL);
337 if (!client)
338 return NULL;
339
340 client->dev = &pdev->dev;
341 client->rx_callback = mbox_test_receive_message;
342 client->tx_prepare = mbox_test_prepare_message;
343 client->tx_done = mbox_test_message_sent;
344 client->tx_block = true;
345 client->knows_txdone = false;
346 client->tx_tout = 500;
347
348 channel = mbox_request_channel_byname(client, name);
349 if (IS_ERR(channel)) {
350 dev_warn(&pdev->dev, "Failed to request %s channel\n", name);
351 return NULL;
352 }
353
354 return channel;
355}
356
357static void __iomem *mbox_test_ioremap(struct platform_device *pdev, unsigned int res_num)
358{
359 struct resource *res;
360 void __iomem *mmio;
361
362 res = platform_get_resource(pdev, IORESOURCE_MEM, res_num);
363 if (!res)
364 return NULL;
365
366 mmio = devm_ioremap_resource(&pdev->dev, res);
367 if (PTR_ERR(mmio) == -EBUSY) {
368 dev_info(&pdev->dev, "trying workaround with plain ioremap\n");
369 return devm_ioremap(&pdev->dev, res->start, resource_size(res));
370 }
371
372 return IS_ERR(mmio) ? NULL : mmio;
373}
374
375static int mbox_test_probe(struct platform_device *pdev)
376{
377 struct mbox_test_device *tdev;
378 int ret;
379
380 tdev = devm_kzalloc(&pdev->dev, sizeof(*tdev), GFP_KERNEL);
381 if (!tdev)
382 return -ENOMEM;
383
384 tdev->dev = &pdev->dev;
385 spin_lock_init(&tdev->lock);
386 mutex_init(&tdev->mutex);
387 init_waitqueue_head(&tdev->waitq);
388 platform_set_drvdata(pdev, tdev);
389
390 /* It's okay for MMIO to be NULL */
391 tdev->tx_mmio = mbox_test_ioremap(pdev, 0);
392
393 /* If specified, second reg entry is Rx MMIO */
394 tdev->rx_mmio = mbox_test_ioremap(pdev, 1);
395 if (!tdev->rx_mmio)
396 tdev->rx_mmio = tdev->tx_mmio;
397
398 tdev->tx_channel = mbox_test_request_channel(pdev, "tx");
399 tdev->rx_channel = mbox_test_request_channel(pdev, "rx");
400
401 if (!tdev->tx_channel && !tdev->rx_channel)
402 return -EPROBE_DEFER;
403
404 /* If Rx is not specified but has Rx MMIO, then Rx = Tx */
405 if (!tdev->rx_channel && (tdev->rx_mmio != tdev->tx_mmio))
406 tdev->rx_channel = tdev->tx_channel;
407
408 if (tdev->rx_channel) {
409 tdev->rx_buffer = devm_kzalloc(&pdev->dev,
410 MBOX_MAX_MSG_LEN, GFP_KERNEL);
411 if (!tdev->rx_buffer) {
412 ret = -ENOMEM;
413 goto err_free_chans;
414 }
415 }
416
417 ret = mbox_test_add_debugfs(pdev, tdev);
418 if (ret)
419 goto err_free_chans;
420
421 dev_info(&pdev->dev, "Successfully registered\n");
422
423 return 0;
424
425err_free_chans:
426 if (tdev->tx_channel)
427 mbox_free_channel(tdev->tx_channel);
428 if (tdev->rx_channel && tdev->rx_channel != tdev->tx_channel)
429 mbox_free_channel(tdev->rx_channel);
430 return ret;
431}
432
433static void mbox_test_remove(struct platform_device *pdev)
434{
435 struct mbox_test_device *tdev = platform_get_drvdata(pdev);
436
437 debugfs_remove_recursive(tdev->root_debugfs_dir);
438
439 if (tdev->tx_channel)
440 mbox_free_channel(tdev->tx_channel);
441 if (tdev->rx_channel && tdev->rx_channel != tdev->tx_channel)
442 mbox_free_channel(tdev->rx_channel);
443}
444
445static const struct of_device_id mbox_test_match[] = {
446 { .compatible = "mailbox-test" },
447 {},
448};
449MODULE_DEVICE_TABLE(of, mbox_test_match);
450
451static struct platform_driver mbox_test_driver = {
452 .driver = {
453 .name = "mailbox_test",
454 .of_match_table = mbox_test_match,
455 },
456 .probe = mbox_test_probe,
457 .remove = mbox_test_remove,
458};
459module_platform_driver(mbox_test_driver);
460
461MODULE_DESCRIPTION("Generic Mailbox Testing Facility");
462MODULE_AUTHOR("Lee Jones <[email protected]");
463MODULE_LICENSE("GPL v2");