1 // SPDX-License-Identifier: (GPL-2.0 OR MIT)
2 /*
3  * Siemens System Memory Buffer driver.
4  * Copyright(c) 2022, HiSilicon Limited.
5  */
6 
7 #include <linux/atomic.h>
8 #include <linux/acpi.h>
9 #include <linux/circ_buf.h>
10 #include <linux/err.h>
11 #include <linux/fs.h>
12 #include <linux/module.h>
13 #include <linux/mod_devicetable.h>
14 #include <linux/platform_device.h>
15 
16 #include "coresight-etm-perf.h"
17 #include "coresight-priv.h"
18 #include "ultrasoc-smb.h"
19 
20 DEFINE_CORESIGHT_DEVLIST(sink_devs, "ultra_smb");
21 
22 #define ULTRASOC_SMB_DSM_UUID	"82ae1283-7f6a-4cbe-aa06-53e8fb24db18"
23 
smb_buffer_not_empty(struct smb_drv_data * drvdata)24 static bool smb_buffer_not_empty(struct smb_drv_data *drvdata)
25 {
26 	u32 buf_status = readl(drvdata->base + SMB_LB_INT_STS_REG);
27 
28 	return FIELD_GET(SMB_LB_INT_STS_NOT_EMPTY_MSK, buf_status);
29 }
30 
smb_update_data_size(struct smb_drv_data * drvdata)31 static void smb_update_data_size(struct smb_drv_data *drvdata)
32 {
33 	struct smb_data_buffer *sdb = &drvdata->sdb;
34 	u32 buf_wrptr;
35 
36 	buf_wrptr = readl(drvdata->base + SMB_LB_WR_ADDR_REG) -
37 			  sdb->buf_hw_base;
38 
39 	/* Buffer is full */
40 	if (buf_wrptr == sdb->buf_rdptr && smb_buffer_not_empty(drvdata)) {
41 		sdb->data_size = sdb->buf_size;
42 		return;
43 	}
44 
45 	/* The buffer mode is circular buffer mode */
46 	sdb->data_size = CIRC_CNT(buf_wrptr, sdb->buf_rdptr,
47 				  sdb->buf_size);
48 }
49 
50 /*
51  * The read pointer adds @nbytes bytes (may round up to the beginning)
52  * after the data is read or discarded, while needing to update the
53  * available data size.
54  */
smb_update_read_ptr(struct smb_drv_data * drvdata,u32 nbytes)55 static void smb_update_read_ptr(struct smb_drv_data *drvdata, u32 nbytes)
56 {
57 	struct smb_data_buffer *sdb = &drvdata->sdb;
58 
59 	sdb->buf_rdptr += nbytes;
60 	sdb->buf_rdptr %= sdb->buf_size;
61 	writel(sdb->buf_hw_base + sdb->buf_rdptr,
62 	       drvdata->base + SMB_LB_RD_ADDR_REG);
63 
64 	sdb->data_size -= nbytes;
65 }
66 
smb_reset_buffer(struct smb_drv_data * drvdata)67 static void smb_reset_buffer(struct smb_drv_data *drvdata)
68 {
69 	struct smb_data_buffer *sdb = &drvdata->sdb;
70 	u32 write_ptr;
71 
72 	/*
73 	 * We must flush and discard any data left in hardware path
74 	 * to avoid corrupting the next session.
75 	 * Note: The write pointer will never exceed the read pointer.
76 	 */
77 	writel(SMB_LB_PURGE_PURGED, drvdata->base + SMB_LB_PURGE_REG);
78 
79 	/* Reset SMB logical buffer status flags */
80 	writel(SMB_LB_INT_STS_RESET, drvdata->base + SMB_LB_INT_STS_REG);
81 
82 	write_ptr = readl(drvdata->base + SMB_LB_WR_ADDR_REG);
83 
84 	/* Do nothing, not data left in hardware path */
85 	if (!write_ptr || write_ptr == sdb->buf_rdptr + sdb->buf_hw_base)
86 		return;
87 
88 	/*
89 	 * The SMB_LB_WR_ADDR_REG register is read-only,
90 	 * Synchronize the read pointer to write pointer.
91 	 */
92 	writel(write_ptr, drvdata->base + SMB_LB_RD_ADDR_REG);
93 	sdb->buf_rdptr = write_ptr - sdb->buf_hw_base;
94 }
95 
smb_open(struct inode * inode,struct file * file)96 static int smb_open(struct inode *inode, struct file *file)
97 {
98 	struct smb_drv_data *drvdata = container_of(file->private_data,
99 					struct smb_drv_data, miscdev);
100 	int ret = 0;
101 
102 	spin_lock(&drvdata->spinlock);
103 
104 	if (drvdata->reading) {
105 		ret = -EBUSY;
106 		goto out;
107 	}
108 
109 	if (atomic_read(&drvdata->csdev->refcnt)) {
110 		ret = -EBUSY;
111 		goto out;
112 	}
113 
114 	smb_update_data_size(drvdata);
115 
116 	drvdata->reading = true;
117 out:
118 	spin_unlock(&drvdata->spinlock);
119 
120 	return ret;
121 }
122 
smb_read(struct file * file,char __user * data,size_t len,loff_t * ppos)123 static ssize_t smb_read(struct file *file, char __user *data, size_t len,
124 			loff_t *ppos)
125 {
126 	struct smb_drv_data *drvdata = container_of(file->private_data,
127 					struct smb_drv_data, miscdev);
128 	struct smb_data_buffer *sdb = &drvdata->sdb;
129 	struct device *dev = &drvdata->csdev->dev;
130 	ssize_t to_copy = 0;
131 
132 	if (!len)
133 		return 0;
134 
135 	if (!sdb->data_size)
136 		return 0;
137 
138 	to_copy = min(sdb->data_size, len);
139 
140 	/* Copy parts of trace data when read pointer wrap around SMB buffer */
141 	if (sdb->buf_rdptr + to_copy > sdb->buf_size)
142 		to_copy = sdb->buf_size - sdb->buf_rdptr;
143 
144 	if (copy_to_user(data, sdb->buf_base + sdb->buf_rdptr, to_copy)) {
145 		dev_dbg(dev, "Failed to copy data to user\n");
146 		return -EFAULT;
147 	}
148 
149 	*ppos += to_copy;
150 	smb_update_read_ptr(drvdata, to_copy);
151 	if (!sdb->data_size)
152 		smb_reset_buffer(drvdata);
153 
154 	dev_dbg(dev, "%zu bytes copied\n", to_copy);
155 	return to_copy;
156 }
157 
smb_release(struct inode * inode,struct file * file)158 static int smb_release(struct inode *inode, struct file *file)
159 {
160 	struct smb_drv_data *drvdata = container_of(file->private_data,
161 					struct smb_drv_data, miscdev);
162 
163 	spin_lock(&drvdata->spinlock);
164 	drvdata->reading = false;
165 	spin_unlock(&drvdata->spinlock);
166 
167 	return 0;
168 }
169 
170 static const struct file_operations smb_fops = {
171 	.owner		= THIS_MODULE,
172 	.open		= smb_open,
173 	.read		= smb_read,
174 	.release	= smb_release,
175 	.llseek		= no_llseek,
176 };
177 
buf_size_show(struct device * dev,struct device_attribute * attr,char * buf)178 static ssize_t buf_size_show(struct device *dev, struct device_attribute *attr,
179 			     char *buf)
180 {
181 	struct smb_drv_data *drvdata = dev_get_drvdata(dev->parent);
182 
183 	return sysfs_emit(buf, "0x%lx\n", drvdata->sdb.buf_size);
184 }
185 static DEVICE_ATTR_RO(buf_size);
186 
187 static struct attribute *smb_sink_attrs[] = {
188 	coresight_simple_reg32(read_pos, SMB_LB_RD_ADDR_REG),
189 	coresight_simple_reg32(write_pos, SMB_LB_WR_ADDR_REG),
190 	coresight_simple_reg32(buf_status, SMB_LB_INT_STS_REG),
191 	&dev_attr_buf_size.attr,
192 	NULL
193 };
194 
195 static const struct attribute_group smb_sink_group = {
196 	.attrs = smb_sink_attrs,
197 	.name = "mgmt",
198 };
199 
200 static const struct attribute_group *smb_sink_groups[] = {
201 	&smb_sink_group,
202 	NULL
203 };
204 
smb_enable_hw(struct smb_drv_data * drvdata)205 static void smb_enable_hw(struct smb_drv_data *drvdata)
206 {
207 	writel(SMB_GLB_EN_HW_ENABLE, drvdata->base + SMB_GLB_EN_REG);
208 }
209 
smb_disable_hw(struct smb_drv_data * drvdata)210 static void smb_disable_hw(struct smb_drv_data *drvdata)
211 {
212 	writel(0x0, drvdata->base + SMB_GLB_EN_REG);
213 }
214 
smb_enable_sysfs(struct coresight_device * csdev)215 static void smb_enable_sysfs(struct coresight_device *csdev)
216 {
217 	struct smb_drv_data *drvdata = dev_get_drvdata(csdev->dev.parent);
218 
219 	if (drvdata->mode != CS_MODE_DISABLED)
220 		return;
221 
222 	smb_enable_hw(drvdata);
223 	drvdata->mode = CS_MODE_SYSFS;
224 }
225 
smb_enable_perf(struct coresight_device * csdev,void * data)226 static int smb_enable_perf(struct coresight_device *csdev, void *data)
227 {
228 	struct smb_drv_data *drvdata = dev_get_drvdata(csdev->dev.parent);
229 	struct perf_output_handle *handle = data;
230 	struct cs_buffers *buf = etm_perf_sink_config(handle);
231 	pid_t pid;
232 
233 	if (!buf)
234 		return -EINVAL;
235 
236 	/* Get a handle on the pid of the target process */
237 	pid = buf->pid;
238 
239 	/* Device is already in used by other session */
240 	if (drvdata->pid != -1 && drvdata->pid != pid)
241 		return -EBUSY;
242 
243 	if (drvdata->pid == -1) {
244 		smb_enable_hw(drvdata);
245 		drvdata->pid = pid;
246 		drvdata->mode = CS_MODE_PERF;
247 	}
248 
249 	return 0;
250 }
251 
smb_enable(struct coresight_device * csdev,enum cs_mode mode,void * data)252 static int smb_enable(struct coresight_device *csdev, enum cs_mode mode,
253 		      void *data)
254 {
255 	struct smb_drv_data *drvdata = dev_get_drvdata(csdev->dev.parent);
256 	int ret = 0;
257 
258 	spin_lock(&drvdata->spinlock);
259 
260 	/* Do nothing, the trace data is reading by other interface now */
261 	if (drvdata->reading) {
262 		ret = -EBUSY;
263 		goto out;
264 	}
265 
266 	/* Do nothing, the SMB is already enabled as other mode */
267 	if (drvdata->mode != CS_MODE_DISABLED && drvdata->mode != mode) {
268 		ret = -EBUSY;
269 		goto out;
270 	}
271 
272 	switch (mode) {
273 	case CS_MODE_SYSFS:
274 		smb_enable_sysfs(csdev);
275 		break;
276 	case CS_MODE_PERF:
277 		ret = smb_enable_perf(csdev, data);
278 		break;
279 	default:
280 		ret = -EINVAL;
281 	}
282 
283 	if (ret)
284 		goto out;
285 
286 	atomic_inc(&csdev->refcnt);
287 
288 	dev_dbg(&csdev->dev, "Ultrasoc SMB enabled\n");
289 out:
290 	spin_unlock(&drvdata->spinlock);
291 
292 	return ret;
293 }
294 
smb_disable(struct coresight_device * csdev)295 static int smb_disable(struct coresight_device *csdev)
296 {
297 	struct smb_drv_data *drvdata = dev_get_drvdata(csdev->dev.parent);
298 	int ret = 0;
299 
300 	spin_lock(&drvdata->spinlock);
301 
302 	if (drvdata->reading) {
303 		ret = -EBUSY;
304 		goto out;
305 	}
306 
307 	if (atomic_dec_return(&csdev->refcnt)) {
308 		ret = -EBUSY;
309 		goto out;
310 	}
311 
312 	/* Complain if we (somehow) got out of sync */
313 	WARN_ON_ONCE(drvdata->mode == CS_MODE_DISABLED);
314 
315 	smb_disable_hw(drvdata);
316 
317 	/* Dissociate from the target process. */
318 	drvdata->pid = -1;
319 	drvdata->mode = CS_MODE_DISABLED;
320 
321 	dev_dbg(&csdev->dev, "Ultrasoc SMB disabled\n");
322 out:
323 	spin_unlock(&drvdata->spinlock);
324 
325 	return ret;
326 }
327 
smb_alloc_buffer(struct coresight_device * csdev,struct perf_event * event,void ** pages,int nr_pages,bool overwrite)328 static void *smb_alloc_buffer(struct coresight_device *csdev,
329 			      struct perf_event *event, void **pages,
330 			      int nr_pages, bool overwrite)
331 {
332 	struct cs_buffers *buf;
333 	int node;
334 
335 	node = (event->cpu == -1) ? NUMA_NO_NODE : cpu_to_node(event->cpu);
336 	buf = kzalloc_node(sizeof(struct cs_buffers), GFP_KERNEL, node);
337 	if (!buf)
338 		return NULL;
339 
340 	buf->snapshot = overwrite;
341 	buf->nr_pages = nr_pages;
342 	buf->data_pages = pages;
343 	buf->pid = task_pid_nr(event->owner);
344 
345 	return buf;
346 }
347 
smb_free_buffer(void * config)348 static void smb_free_buffer(void *config)
349 {
350 	struct cs_buffers *buf = config;
351 
352 	kfree(buf);
353 }
354 
smb_sync_perf_buffer(struct smb_drv_data * drvdata,struct cs_buffers * buf,unsigned long head)355 static void smb_sync_perf_buffer(struct smb_drv_data *drvdata,
356 				 struct cs_buffers *buf,
357 				 unsigned long head)
358 {
359 	struct smb_data_buffer *sdb = &drvdata->sdb;
360 	char **dst_pages = (char **)buf->data_pages;
361 	unsigned long to_copy;
362 	long pg_idx, pg_offset;
363 
364 	pg_idx = head >> PAGE_SHIFT;
365 	pg_offset = head & (PAGE_SIZE - 1);
366 
367 	while (sdb->data_size) {
368 		unsigned long pg_space = PAGE_SIZE - pg_offset;
369 
370 		to_copy = min(sdb->data_size, pg_space);
371 
372 		/* Copy parts of trace data when read pointer wrap around */
373 		if (sdb->buf_rdptr + to_copy > sdb->buf_size)
374 			to_copy = sdb->buf_size - sdb->buf_rdptr;
375 
376 		memcpy(dst_pages[pg_idx] + pg_offset,
377 			      sdb->buf_base + sdb->buf_rdptr, to_copy);
378 
379 		pg_offset += to_copy;
380 		if (pg_offset >= PAGE_SIZE) {
381 			pg_offset = 0;
382 			pg_idx++;
383 			pg_idx %= buf->nr_pages;
384 		}
385 		smb_update_read_ptr(drvdata, to_copy);
386 	}
387 
388 	smb_reset_buffer(drvdata);
389 }
390 
smb_update_buffer(struct coresight_device * csdev,struct perf_output_handle * handle,void * sink_config)391 static unsigned long smb_update_buffer(struct coresight_device *csdev,
392 				       struct perf_output_handle *handle,
393 				       void *sink_config)
394 {
395 	struct smb_drv_data *drvdata = dev_get_drvdata(csdev->dev.parent);
396 	struct smb_data_buffer *sdb = &drvdata->sdb;
397 	struct cs_buffers *buf = sink_config;
398 	unsigned long data_size = 0;
399 	bool lost = false;
400 
401 	if (!buf)
402 		return 0;
403 
404 	spin_lock(&drvdata->spinlock);
405 
406 	/* Don't do anything if another tracer is using this sink. */
407 	if (atomic_read(&csdev->refcnt) != 1)
408 		goto out;
409 
410 	smb_disable_hw(drvdata);
411 	smb_update_data_size(drvdata);
412 
413 	/*
414 	 * The SMB buffer may be bigger than the space available in the
415 	 * perf ring buffer (handle->size). If so advance the offset so
416 	 * that we get the latest trace data.
417 	 */
418 	if (sdb->data_size > handle->size) {
419 		smb_update_read_ptr(drvdata, sdb->data_size - handle->size);
420 		lost = true;
421 	}
422 
423 	data_size = sdb->data_size;
424 	smb_sync_perf_buffer(drvdata, buf, handle->head);
425 	if (!buf->snapshot && lost)
426 		perf_aux_output_flag(handle, PERF_AUX_FLAG_TRUNCATED);
427 out:
428 	spin_unlock(&drvdata->spinlock);
429 
430 	return data_size;
431 }
432 
433 static const struct coresight_ops_sink smb_cs_ops = {
434 	.enable		= smb_enable,
435 	.disable	= smb_disable,
436 	.alloc_buffer	= smb_alloc_buffer,
437 	.free_buffer	= smb_free_buffer,
438 	.update_buffer	= smb_update_buffer,
439 };
440 
441 static const struct coresight_ops cs_ops = {
442 	.sink_ops	= &smb_cs_ops,
443 };
444 
smb_init_data_buffer(struct platform_device * pdev,struct smb_data_buffer * sdb)445 static int smb_init_data_buffer(struct platform_device *pdev,
446 				struct smb_data_buffer *sdb)
447 {
448 	struct resource *res;
449 	void *base;
450 
451 	res = platform_get_resource(pdev, IORESOURCE_MEM, SMB_BUF_ADDR_RES);
452 	if (!res) {
453 		dev_err(&pdev->dev, "SMB device failed to get resource\n");
454 		return -EINVAL;
455 	}
456 
457 	sdb->buf_rdptr = 0;
458 	sdb->buf_hw_base = FIELD_GET(SMB_BUF_ADDR_LO_MSK, res->start);
459 	sdb->buf_size = resource_size(res);
460 	if (sdb->buf_size == 0)
461 		return -EINVAL;
462 
463 	/*
464 	 * This is a chunk of memory, use classic mapping with better
465 	 * performance.
466 	 */
467 	base = devm_memremap(&pdev->dev, sdb->buf_hw_base, sdb->buf_size,
468 				MEMREMAP_WB);
469 	if (IS_ERR(base))
470 		return PTR_ERR(base);
471 
472 	sdb->buf_base = base;
473 
474 	return 0;
475 }
476 
smb_init_hw(struct smb_drv_data * drvdata)477 static void smb_init_hw(struct smb_drv_data *drvdata)
478 {
479 	smb_disable_hw(drvdata);
480 
481 	writel(SMB_LB_CFG_LO_DEFAULT, drvdata->base + SMB_LB_CFG_LO_REG);
482 	writel(SMB_LB_CFG_HI_DEFAULT, drvdata->base + SMB_LB_CFG_HI_REG);
483 	writel(SMB_GLB_CFG_DEFAULT, drvdata->base + SMB_GLB_CFG_REG);
484 	writel(SMB_GLB_INT_CFG, drvdata->base + SMB_GLB_INT_REG);
485 	writel(SMB_LB_INT_CTRL_CFG, drvdata->base + SMB_LB_INT_CTRL_REG);
486 }
487 
smb_register_sink(struct platform_device * pdev,struct smb_drv_data * drvdata)488 static int smb_register_sink(struct platform_device *pdev,
489 			     struct smb_drv_data *drvdata)
490 {
491 	struct coresight_platform_data *pdata = NULL;
492 	struct coresight_desc desc = { 0 };
493 	int ret;
494 
495 	pdata = coresight_get_platform_data(&pdev->dev);
496 	if (IS_ERR(pdata))
497 		return PTR_ERR(pdata);
498 
499 	desc.type = CORESIGHT_DEV_TYPE_SINK;
500 	desc.subtype.sink_subtype = CORESIGHT_DEV_SUBTYPE_SINK_BUFFER;
501 	desc.ops = &cs_ops;
502 	desc.pdata = pdata;
503 	desc.dev = &pdev->dev;
504 	desc.groups = smb_sink_groups;
505 	desc.name = coresight_alloc_device_name(&sink_devs, &pdev->dev);
506 	if (!desc.name) {
507 		dev_err(&pdev->dev, "Failed to alloc coresight device name");
508 		return -ENOMEM;
509 	}
510 	desc.access = CSDEV_ACCESS_IOMEM(drvdata->base);
511 
512 	drvdata->csdev = coresight_register(&desc);
513 	if (IS_ERR(drvdata->csdev))
514 		return PTR_ERR(drvdata->csdev);
515 
516 	drvdata->miscdev.name = desc.name;
517 	drvdata->miscdev.minor = MISC_DYNAMIC_MINOR;
518 	drvdata->miscdev.fops = &smb_fops;
519 	ret = misc_register(&drvdata->miscdev);
520 	if (ret) {
521 		coresight_unregister(drvdata->csdev);
522 		dev_err(&pdev->dev, "Failed to register misc, ret=%d\n", ret);
523 	}
524 
525 	return ret;
526 }
527 
smb_unregister_sink(struct smb_drv_data * drvdata)528 static void smb_unregister_sink(struct smb_drv_data *drvdata)
529 {
530 	misc_deregister(&drvdata->miscdev);
531 	coresight_unregister(drvdata->csdev);
532 }
533 
smb_config_inport(struct device * dev,bool enable)534 static int smb_config_inport(struct device *dev, bool enable)
535 {
536 	u64 func = enable ? 1 : 0;
537 	union acpi_object *obj;
538 	guid_t guid;
539 	u64 rev = 0;
540 
541 	/*
542 	 * Using DSM calls to enable/disable ultrasoc hardwares on
543 	 * tracing path, to prevent ultrasoc packet format being exposed.
544 	 */
545 	if (guid_parse(ULTRASOC_SMB_DSM_UUID, &guid)) {
546 		dev_err(dev, "Get GUID failed\n");
547 		return -EINVAL;
548 	}
549 
550 	obj = acpi_evaluate_dsm(ACPI_HANDLE(dev), &guid, rev, func, NULL);
551 	if (!obj) {
552 		dev_err(dev, "ACPI handle failed\n");
553 		return -ENODEV;
554 	}
555 
556 	ACPI_FREE(obj);
557 
558 	return 0;
559 }
560 
smb_probe(struct platform_device * pdev)561 static int smb_probe(struct platform_device *pdev)
562 {
563 	struct device *dev = &pdev->dev;
564 	struct smb_drv_data *drvdata;
565 	int ret;
566 
567 	drvdata = devm_kzalloc(dev, sizeof(*drvdata), GFP_KERNEL);
568 	if (!drvdata)
569 		return -ENOMEM;
570 
571 	drvdata->base = devm_platform_ioremap_resource(pdev, SMB_REG_ADDR_RES);
572 	if (IS_ERR(drvdata->base)) {
573 		dev_err(dev, "Failed to ioremap resource\n");
574 		return PTR_ERR(drvdata->base);
575 	}
576 
577 	smb_init_hw(drvdata);
578 
579 	ret = smb_init_data_buffer(pdev, &drvdata->sdb);
580 	if (ret) {
581 		dev_err(dev, "Failed to init buffer, ret = %d\n", ret);
582 		return ret;
583 	}
584 
585 	ret = smb_config_inport(dev, true);
586 	if (ret)
587 		return ret;
588 
589 	smb_reset_buffer(drvdata);
590 	platform_set_drvdata(pdev, drvdata);
591 	spin_lock_init(&drvdata->spinlock);
592 	drvdata->pid = -1;
593 
594 	ret = smb_register_sink(pdev, drvdata);
595 	if (ret) {
596 		smb_config_inport(&pdev->dev, false);
597 		dev_err(dev, "Failed to register SMB sink\n");
598 		return ret;
599 	}
600 
601 	return 0;
602 }
603 
smb_remove(struct platform_device * pdev)604 static int smb_remove(struct platform_device *pdev)
605 {
606 	struct smb_drv_data *drvdata = platform_get_drvdata(pdev);
607 
608 	smb_unregister_sink(drvdata);
609 
610 	smb_config_inport(&pdev->dev, false);
611 
612 	return 0;
613 }
614 
615 #ifdef CONFIG_ACPI
616 static const struct acpi_device_id ultrasoc_smb_acpi_match[] = {
617 	{"HISI03A1", 0},
618 	{}
619 };
620 MODULE_DEVICE_TABLE(acpi, ultrasoc_smb_acpi_match);
621 #endif
622 
623 static struct platform_driver smb_driver = {
624 	.driver = {
625 		.name = "ultrasoc-smb",
626 		.acpi_match_table = ACPI_PTR(ultrasoc_smb_acpi_match),
627 		.suppress_bind_attrs = true,
628 	},
629 	.probe = smb_probe,
630 	.remove = smb_remove,
631 };
632 module_platform_driver(smb_driver);
633 
634 MODULE_DESCRIPTION("UltraSoc SMB CoreSight driver");
635 MODULE_LICENSE("Dual MIT/GPL");
636 MODULE_AUTHOR("Jonathan Zhou <jonathan.zhouwen@huawei.com>");
637 MODULE_AUTHOR("Qi Liu <liuqi115@huawei.com>");
638