1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Copyright (c) 2011-2012, The Linux Foundation. All rights reserved.
4  *
5  * Description: CoreSight Embedded Trace Buffer driver
6  */
7 
8 #include <asm/local.h>
9 #include <linux/kernel.h>
10 #include <linux/init.h>
11 #include <linux/types.h>
12 #include <linux/device.h>
13 #include <linux/io.h>
14 #include <linux/err.h>
15 #include <linux/fs.h>
16 #include <linux/miscdevice.h>
17 #include <linux/uaccess.h>
18 #include <linux/slab.h>
19 #include <linux/spinlock.h>
20 #include <linux/pm_runtime.h>
21 #include <linux/seq_file.h>
22 #include <linux/coresight.h>
23 #include <linux/amba/bus.h>
24 #include <linux/clk.h>
25 #include <linux/circ_buf.h>
26 #include <linux/mm.h>
27 #include <linux/perf_event.h>
28 
29 
30 #include "coresight-priv.h"
31 
32 #define ETB_RAM_DEPTH_REG	0x004
33 #define ETB_STATUS_REG		0x00c
34 #define ETB_RAM_READ_DATA_REG	0x010
35 #define ETB_RAM_READ_POINTER	0x014
36 #define ETB_RAM_WRITE_POINTER	0x018
37 #define ETB_TRG			0x01c
38 #define ETB_CTL_REG		0x020
39 #define ETB_RWD_REG		0x024
40 #define ETB_FFSR		0x300
41 #define ETB_FFCR		0x304
42 #define ETB_ITMISCOP0		0xee0
43 #define ETB_ITTRFLINACK		0xee4
44 #define ETB_ITTRFLIN		0xee8
45 #define ETB_ITATBDATA0		0xeeC
46 #define ETB_ITATBCTR2		0xef0
47 #define ETB_ITATBCTR1		0xef4
48 #define ETB_ITATBCTR0		0xef8
49 
50 /* register description */
51 /* STS - 0x00C */
52 #define ETB_STATUS_RAM_FULL	BIT(0)
53 /* CTL - 0x020 */
54 #define ETB_CTL_CAPT_EN		BIT(0)
55 /* FFCR - 0x304 */
56 #define ETB_FFCR_EN_FTC		BIT(0)
57 #define ETB_FFCR_FON_MAN	BIT(6)
58 #define ETB_FFCR_STOP_FI	BIT(12)
59 #define ETB_FFCR_STOP_TRIGGER	BIT(13)
60 
61 #define ETB_FFCR_BIT		6
62 #define ETB_FFSR_BIT		1
63 #define ETB_FRAME_SIZE_WORDS	4
64 
65 /**
66  * struct etb_drvdata - specifics associated to an ETB component
67  * @base:	memory mapped base address for this component.
68  * @dev:	the device entity associated to this component.
69  * @atclk:	optional clock for the core parts of the ETB.
70  * @csdev:	component vitals needed by the framework.
71  * @miscdev:	specifics to handle "/dev/xyz.etb" entry.
72  * @spinlock:	only one at a time pls.
73  * @reading:	synchronise user space access to etb buffer.
74  * @mode:	this ETB is being used.
75  * @buf:	area of memory where ETB buffer content gets sent.
76  * @buffer_depth: size of @buf.
77  * @trigger_cntr: amount of words to store after a trigger.
78  */
79 struct etb_drvdata {
80 	void __iomem		*base;
81 	struct device		*dev;
82 	struct clk		*atclk;
83 	struct coresight_device	*csdev;
84 	struct miscdevice	miscdev;
85 	spinlock_t		spinlock;
86 	local_t			reading;
87 	local_t			mode;
88 	u8			*buf;
89 	u32			buffer_depth;
90 	u32			trigger_cntr;
91 };
92 
93 static unsigned int etb_get_buffer_depth(struct etb_drvdata *drvdata)
94 {
95 	u32 depth = 0;
96 
97 	pm_runtime_get_sync(drvdata->dev);
98 
99 	/* RO registers don't need locking */
100 	depth = readl_relaxed(drvdata->base + ETB_RAM_DEPTH_REG);
101 
102 	pm_runtime_put(drvdata->dev);
103 	return depth;
104 }
105 
106 static void etb_enable_hw(struct etb_drvdata *drvdata)
107 {
108 	int i;
109 	u32 depth;
110 
111 	CS_UNLOCK(drvdata->base);
112 
113 	depth = drvdata->buffer_depth;
114 	/* reset write RAM pointer address */
115 	writel_relaxed(0x0, drvdata->base + ETB_RAM_WRITE_POINTER);
116 	/* clear entire RAM buffer */
117 	for (i = 0; i < depth; i++)
118 		writel_relaxed(0x0, drvdata->base + ETB_RWD_REG);
119 
120 	/* reset write RAM pointer address */
121 	writel_relaxed(0x0, drvdata->base + ETB_RAM_WRITE_POINTER);
122 	/* reset read RAM pointer address */
123 	writel_relaxed(0x0, drvdata->base + ETB_RAM_READ_POINTER);
124 
125 	writel_relaxed(drvdata->trigger_cntr, drvdata->base + ETB_TRG);
126 	writel_relaxed(ETB_FFCR_EN_FTC | ETB_FFCR_STOP_TRIGGER,
127 		       drvdata->base + ETB_FFCR);
128 	/* ETB trace capture enable */
129 	writel_relaxed(ETB_CTL_CAPT_EN, drvdata->base + ETB_CTL_REG);
130 
131 	CS_LOCK(drvdata->base);
132 }
133 
134 static int etb_enable(struct coresight_device *csdev, u32 mode)
135 {
136 	u32 val;
137 	unsigned long flags;
138 	struct etb_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);
139 
140 	val = local_cmpxchg(&drvdata->mode,
141 			    CS_MODE_DISABLED, mode);
142 	/*
143 	 * When accessing from Perf, a HW buffer can be handled
144 	 * by a single trace entity.  In sysFS mode many tracers
145 	 * can be logging to the same HW buffer.
146 	 */
147 	if (val == CS_MODE_PERF)
148 		return -EBUSY;
149 
150 	/* Nothing to do, the tracer is already enabled. */
151 	if (val == CS_MODE_SYSFS)
152 		goto out;
153 
154 	spin_lock_irqsave(&drvdata->spinlock, flags);
155 	etb_enable_hw(drvdata);
156 	spin_unlock_irqrestore(&drvdata->spinlock, flags);
157 
158 out:
159 	dev_info(drvdata->dev, "ETB enabled\n");
160 	return 0;
161 }
162 
163 static void etb_disable_hw(struct etb_drvdata *drvdata)
164 {
165 	u32 ffcr;
166 
167 	CS_UNLOCK(drvdata->base);
168 
169 	ffcr = readl_relaxed(drvdata->base + ETB_FFCR);
170 	/* stop formatter when a stop has completed */
171 	ffcr |= ETB_FFCR_STOP_FI;
172 	writel_relaxed(ffcr, drvdata->base + ETB_FFCR);
173 	/* manually generate a flush of the system */
174 	ffcr |= ETB_FFCR_FON_MAN;
175 	writel_relaxed(ffcr, drvdata->base + ETB_FFCR);
176 
177 	if (coresight_timeout(drvdata->base, ETB_FFCR, ETB_FFCR_BIT, 0)) {
178 		dev_err(drvdata->dev,
179 		"timeout while waiting for completion of Manual Flush\n");
180 	}
181 
182 	/* disable trace capture */
183 	writel_relaxed(0x0, drvdata->base + ETB_CTL_REG);
184 
185 	if (coresight_timeout(drvdata->base, ETB_FFSR, ETB_FFSR_BIT, 1)) {
186 		dev_err(drvdata->dev,
187 			"timeout while waiting for Formatter to Stop\n");
188 	}
189 
190 	CS_LOCK(drvdata->base);
191 }
192 
193 static void etb_dump_hw(struct etb_drvdata *drvdata)
194 {
195 	bool lost = false;
196 	int i;
197 	u8 *buf_ptr;
198 	u32 read_data, depth;
199 	u32 read_ptr, write_ptr;
200 	u32 frame_off, frame_endoff;
201 
202 	CS_UNLOCK(drvdata->base);
203 
204 	read_ptr = readl_relaxed(drvdata->base + ETB_RAM_READ_POINTER);
205 	write_ptr = readl_relaxed(drvdata->base + ETB_RAM_WRITE_POINTER);
206 
207 	frame_off = write_ptr % ETB_FRAME_SIZE_WORDS;
208 	frame_endoff = ETB_FRAME_SIZE_WORDS - frame_off;
209 	if (frame_off) {
210 		dev_err(drvdata->dev,
211 			"write_ptr: %lu not aligned to formatter frame size\n",
212 			(unsigned long)write_ptr);
213 		dev_err(drvdata->dev, "frameoff: %lu, frame_endoff: %lu\n",
214 			(unsigned long)frame_off, (unsigned long)frame_endoff);
215 		write_ptr += frame_endoff;
216 	}
217 
218 	if ((readl_relaxed(drvdata->base + ETB_STATUS_REG)
219 		      & ETB_STATUS_RAM_FULL) == 0) {
220 		writel_relaxed(0x0, drvdata->base + ETB_RAM_READ_POINTER);
221 	} else {
222 		writel_relaxed(write_ptr, drvdata->base + ETB_RAM_READ_POINTER);
223 		lost = true;
224 	}
225 
226 	depth = drvdata->buffer_depth;
227 	buf_ptr = drvdata->buf;
228 	for (i = 0; i < depth; i++) {
229 		read_data = readl_relaxed(drvdata->base +
230 					  ETB_RAM_READ_DATA_REG);
231 		*(u32 *)buf_ptr = read_data;
232 		buf_ptr += 4;
233 	}
234 
235 	if (lost)
236 		coresight_insert_barrier_packet(drvdata->buf);
237 
238 	if (frame_off) {
239 		buf_ptr -= (frame_endoff * 4);
240 		for (i = 0; i < frame_endoff; i++) {
241 			*buf_ptr++ = 0x0;
242 			*buf_ptr++ = 0x0;
243 			*buf_ptr++ = 0x0;
244 			*buf_ptr++ = 0x0;
245 		}
246 	}
247 
248 	writel_relaxed(read_ptr, drvdata->base + ETB_RAM_READ_POINTER);
249 
250 	CS_LOCK(drvdata->base);
251 }
252 
253 static void etb_disable(struct coresight_device *csdev)
254 {
255 	struct etb_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);
256 	unsigned long flags;
257 
258 	spin_lock_irqsave(&drvdata->spinlock, flags);
259 	etb_disable_hw(drvdata);
260 	etb_dump_hw(drvdata);
261 	spin_unlock_irqrestore(&drvdata->spinlock, flags);
262 
263 	local_set(&drvdata->mode, CS_MODE_DISABLED);
264 
265 	dev_info(drvdata->dev, "ETB disabled\n");
266 }
267 
268 static void *etb_alloc_buffer(struct coresight_device *csdev, int cpu,
269 			      void **pages, int nr_pages, bool overwrite)
270 {
271 	int node;
272 	struct cs_buffers *buf;
273 
274 	if (cpu == -1)
275 		cpu = smp_processor_id();
276 	node = cpu_to_node(cpu);
277 
278 	buf = kzalloc_node(sizeof(struct cs_buffers), GFP_KERNEL, node);
279 	if (!buf)
280 		return NULL;
281 
282 	buf->snapshot = overwrite;
283 	buf->nr_pages = nr_pages;
284 	buf->data_pages = pages;
285 
286 	return buf;
287 }
288 
289 static void etb_free_buffer(void *config)
290 {
291 	struct cs_buffers *buf = config;
292 
293 	kfree(buf);
294 }
295 
296 static int etb_set_buffer(struct coresight_device *csdev,
297 			  struct perf_output_handle *handle,
298 			  void *sink_config)
299 {
300 	int ret = 0;
301 	unsigned long head;
302 	struct cs_buffers *buf = sink_config;
303 
304 	/* wrap head around to the amount of space we have */
305 	head = handle->head & ((buf->nr_pages << PAGE_SHIFT) - 1);
306 
307 	/* find the page to write to */
308 	buf->cur = head / PAGE_SIZE;
309 
310 	/* and offset within that page */
311 	buf->offset = head % PAGE_SIZE;
312 
313 	local_set(&buf->data_size, 0);
314 
315 	return ret;
316 }
317 
318 static unsigned long etb_reset_buffer(struct coresight_device *csdev,
319 				      struct perf_output_handle *handle,
320 				      void *sink_config)
321 {
322 	unsigned long size = 0;
323 	struct cs_buffers *buf = sink_config;
324 
325 	if (buf) {
326 		/*
327 		 * In snapshot mode ->data_size holds the new address of the
328 		 * ring buffer's head.  The size itself is the whole address
329 		 * range since we want the latest information.
330 		 */
331 		if (buf->snapshot)
332 			handle->head = local_xchg(&buf->data_size,
333 						  buf->nr_pages << PAGE_SHIFT);
334 
335 		/*
336 		 * Tell the tracer PMU how much we got in this run and if
337 		 * something went wrong along the way.  Nobody else can use
338 		 * this cs_buffers instance until we are done.  As such
339 		 * resetting parameters here and squaring off with the ring
340 		 * buffer API in the tracer PMU is fine.
341 		 */
342 		size = local_xchg(&buf->data_size, 0);
343 	}
344 
345 	return size;
346 }
347 
348 static void etb_update_buffer(struct coresight_device *csdev,
349 			      struct perf_output_handle *handle,
350 			      void *sink_config)
351 {
352 	bool lost = false;
353 	int i, cur;
354 	u8 *buf_ptr;
355 	const u32 *barrier;
356 	u32 read_ptr, write_ptr, capacity;
357 	u32 status, read_data, to_read;
358 	unsigned long offset;
359 	struct cs_buffers *buf = sink_config;
360 	struct etb_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);
361 
362 	if (!buf)
363 		return;
364 
365 	capacity = drvdata->buffer_depth * ETB_FRAME_SIZE_WORDS;
366 
367 	etb_disable_hw(drvdata);
368 	CS_UNLOCK(drvdata->base);
369 
370 	/* unit is in words, not bytes */
371 	read_ptr = readl_relaxed(drvdata->base + ETB_RAM_READ_POINTER);
372 	write_ptr = readl_relaxed(drvdata->base + ETB_RAM_WRITE_POINTER);
373 
374 	/*
375 	 * Entries should be aligned to the frame size.  If they are not
376 	 * go back to the last alignment point to give decoding tools a
377 	 * chance to fix things.
378 	 */
379 	if (write_ptr % ETB_FRAME_SIZE_WORDS) {
380 		dev_err(drvdata->dev,
381 			"write_ptr: %lu not aligned to formatter frame size\n",
382 			(unsigned long)write_ptr);
383 
384 		write_ptr &= ~(ETB_FRAME_SIZE_WORDS - 1);
385 		lost = true;
386 	}
387 
388 	/*
389 	 * Get a hold of the status register and see if a wrap around
390 	 * has occurred.  If so adjust things accordingly.  Otherwise
391 	 * start at the beginning and go until the write pointer has
392 	 * been reached.
393 	 */
394 	status = readl_relaxed(drvdata->base + ETB_STATUS_REG);
395 	if (status & ETB_STATUS_RAM_FULL) {
396 		lost = true;
397 		to_read = capacity;
398 		read_ptr = write_ptr;
399 	} else {
400 		to_read = CIRC_CNT(write_ptr, read_ptr, drvdata->buffer_depth);
401 		to_read *= ETB_FRAME_SIZE_WORDS;
402 	}
403 
404 	/*
405 	 * Make sure we don't overwrite data that hasn't been consumed yet.
406 	 * It is entirely possible that the HW buffer has more data than the
407 	 * ring buffer can currently handle.  If so adjust the start address
408 	 * to take only the last traces.
409 	 *
410 	 * In snapshot mode we are looking to get the latest traces only and as
411 	 * such, we don't care about not overwriting data that hasn't been
412 	 * processed by user space.
413 	 */
414 	if (!buf->snapshot && to_read > handle->size) {
415 		u32 mask = ~(ETB_FRAME_SIZE_WORDS - 1);
416 
417 		/* The new read pointer must be frame size aligned */
418 		to_read = handle->size & mask;
419 		/*
420 		 * Move the RAM read pointer up, keeping in mind that
421 		 * everything is in frame size units.
422 		 */
423 		read_ptr = (write_ptr + drvdata->buffer_depth) -
424 					to_read / ETB_FRAME_SIZE_WORDS;
425 		/* Wrap around if need be*/
426 		if (read_ptr > (drvdata->buffer_depth - 1))
427 			read_ptr -= drvdata->buffer_depth;
428 		/* let the decoder know we've skipped ahead */
429 		lost = true;
430 	}
431 
432 	if (lost)
433 		perf_aux_output_flag(handle, PERF_AUX_FLAG_TRUNCATED);
434 
435 	/* finally tell HW where we want to start reading from */
436 	writel_relaxed(read_ptr, drvdata->base + ETB_RAM_READ_POINTER);
437 
438 	cur = buf->cur;
439 	offset = buf->offset;
440 	barrier = barrier_pkt;
441 
442 	for (i = 0; i < to_read; i += 4) {
443 		buf_ptr = buf->data_pages[cur] + offset;
444 		read_data = readl_relaxed(drvdata->base +
445 					  ETB_RAM_READ_DATA_REG);
446 		if (lost && i < CORESIGHT_BARRIER_PKT_SIZE) {
447 			read_data = *barrier;
448 			barrier++;
449 		}
450 
451 		*(u32 *)buf_ptr = read_data;
452 		buf_ptr += 4;
453 
454 		offset += 4;
455 		if (offset >= PAGE_SIZE) {
456 			offset = 0;
457 			cur++;
458 			/* wrap around at the end of the buffer */
459 			cur &= buf->nr_pages - 1;
460 		}
461 	}
462 
463 	/* reset ETB buffer for next run */
464 	writel_relaxed(0x0, drvdata->base + ETB_RAM_READ_POINTER);
465 	writel_relaxed(0x0, drvdata->base + ETB_RAM_WRITE_POINTER);
466 
467 	/*
468 	 * In snapshot mode all we have to do is communicate to
469 	 * perf_aux_output_end() the address of the current head.  In full
470 	 * trace mode the same function expects a size to move rb->aux_head
471 	 * forward.
472 	 */
473 	if (buf->snapshot)
474 		local_set(&buf->data_size, (cur * PAGE_SIZE) + offset);
475 	else
476 		local_add(to_read, &buf->data_size);
477 
478 	etb_enable_hw(drvdata);
479 	CS_LOCK(drvdata->base);
480 }
481 
482 static const struct coresight_ops_sink etb_sink_ops = {
483 	.enable		= etb_enable,
484 	.disable	= etb_disable,
485 	.alloc_buffer	= etb_alloc_buffer,
486 	.free_buffer	= etb_free_buffer,
487 	.set_buffer	= etb_set_buffer,
488 	.reset_buffer	= etb_reset_buffer,
489 	.update_buffer	= etb_update_buffer,
490 };
491 
492 static const struct coresight_ops etb_cs_ops = {
493 	.sink_ops	= &etb_sink_ops,
494 };
495 
496 static void etb_dump(struct etb_drvdata *drvdata)
497 {
498 	unsigned long flags;
499 
500 	spin_lock_irqsave(&drvdata->spinlock, flags);
501 	if (local_read(&drvdata->mode) == CS_MODE_SYSFS) {
502 		etb_disable_hw(drvdata);
503 		etb_dump_hw(drvdata);
504 		etb_enable_hw(drvdata);
505 	}
506 	spin_unlock_irqrestore(&drvdata->spinlock, flags);
507 
508 	dev_info(drvdata->dev, "ETB dumped\n");
509 }
510 
511 static int etb_open(struct inode *inode, struct file *file)
512 {
513 	struct etb_drvdata *drvdata = container_of(file->private_data,
514 						   struct etb_drvdata, miscdev);
515 
516 	if (local_cmpxchg(&drvdata->reading, 0, 1))
517 		return -EBUSY;
518 
519 	dev_dbg(drvdata->dev, "%s: successfully opened\n", __func__);
520 	return 0;
521 }
522 
523 static ssize_t etb_read(struct file *file, char __user *data,
524 				size_t len, loff_t *ppos)
525 {
526 	u32 depth;
527 	struct etb_drvdata *drvdata = container_of(file->private_data,
528 						   struct etb_drvdata, miscdev);
529 
530 	etb_dump(drvdata);
531 
532 	depth = drvdata->buffer_depth;
533 	if (*ppos + len > depth * 4)
534 		len = depth * 4 - *ppos;
535 
536 	if (copy_to_user(data, drvdata->buf + *ppos, len)) {
537 		dev_dbg(drvdata->dev, "%s: copy_to_user failed\n", __func__);
538 		return -EFAULT;
539 	}
540 
541 	*ppos += len;
542 
543 	dev_dbg(drvdata->dev, "%s: %zu bytes copied, %d bytes left\n",
544 		__func__, len, (int)(depth * 4 - *ppos));
545 	return len;
546 }
547 
548 static int etb_release(struct inode *inode, struct file *file)
549 {
550 	struct etb_drvdata *drvdata = container_of(file->private_data,
551 						   struct etb_drvdata, miscdev);
552 	local_set(&drvdata->reading, 0);
553 
554 	dev_dbg(drvdata->dev, "%s: released\n", __func__);
555 	return 0;
556 }
557 
558 static const struct file_operations etb_fops = {
559 	.owner		= THIS_MODULE,
560 	.open		= etb_open,
561 	.read		= etb_read,
562 	.release	= etb_release,
563 	.llseek		= no_llseek,
564 };
565 
566 #define coresight_etb10_reg(name, offset)		\
567 	coresight_simple_reg32(struct etb_drvdata, name, offset)
568 
569 coresight_etb10_reg(rdp, ETB_RAM_DEPTH_REG);
570 coresight_etb10_reg(sts, ETB_STATUS_REG);
571 coresight_etb10_reg(rrp, ETB_RAM_READ_POINTER);
572 coresight_etb10_reg(rwp, ETB_RAM_WRITE_POINTER);
573 coresight_etb10_reg(trg, ETB_TRG);
574 coresight_etb10_reg(ctl, ETB_CTL_REG);
575 coresight_etb10_reg(ffsr, ETB_FFSR);
576 coresight_etb10_reg(ffcr, ETB_FFCR);
577 
578 static struct attribute *coresight_etb_mgmt_attrs[] = {
579 	&dev_attr_rdp.attr,
580 	&dev_attr_sts.attr,
581 	&dev_attr_rrp.attr,
582 	&dev_attr_rwp.attr,
583 	&dev_attr_trg.attr,
584 	&dev_attr_ctl.attr,
585 	&dev_attr_ffsr.attr,
586 	&dev_attr_ffcr.attr,
587 	NULL,
588 };
589 
590 static ssize_t trigger_cntr_show(struct device *dev,
591 			    struct device_attribute *attr, char *buf)
592 {
593 	struct etb_drvdata *drvdata = dev_get_drvdata(dev->parent);
594 	unsigned long val = drvdata->trigger_cntr;
595 
596 	return sprintf(buf, "%#lx\n", val);
597 }
598 
599 static ssize_t trigger_cntr_store(struct device *dev,
600 			     struct device_attribute *attr,
601 			     const char *buf, size_t size)
602 {
603 	int ret;
604 	unsigned long val;
605 	struct etb_drvdata *drvdata = dev_get_drvdata(dev->parent);
606 
607 	ret = kstrtoul(buf, 16, &val);
608 	if (ret)
609 		return ret;
610 
611 	drvdata->trigger_cntr = val;
612 	return size;
613 }
614 static DEVICE_ATTR_RW(trigger_cntr);
615 
616 static struct attribute *coresight_etb_attrs[] = {
617 	&dev_attr_trigger_cntr.attr,
618 	NULL,
619 };
620 
621 static const struct attribute_group coresight_etb_group = {
622 	.attrs = coresight_etb_attrs,
623 };
624 
625 static const struct attribute_group coresight_etb_mgmt_group = {
626 	.attrs = coresight_etb_mgmt_attrs,
627 	.name = "mgmt",
628 };
629 
630 const struct attribute_group *coresight_etb_groups[] = {
631 	&coresight_etb_group,
632 	&coresight_etb_mgmt_group,
633 	NULL,
634 };
635 
636 static int etb_probe(struct amba_device *adev, const struct amba_id *id)
637 {
638 	int ret;
639 	void __iomem *base;
640 	struct device *dev = &adev->dev;
641 	struct coresight_platform_data *pdata = NULL;
642 	struct etb_drvdata *drvdata;
643 	struct resource *res = &adev->res;
644 	struct coresight_desc desc = { 0 };
645 	struct device_node *np = adev->dev.of_node;
646 
647 	if (np) {
648 		pdata = of_get_coresight_platform_data(dev, np);
649 		if (IS_ERR(pdata))
650 			return PTR_ERR(pdata);
651 		adev->dev.platform_data = pdata;
652 	}
653 
654 	drvdata = devm_kzalloc(dev, sizeof(*drvdata), GFP_KERNEL);
655 	if (!drvdata)
656 		return -ENOMEM;
657 
658 	drvdata->dev = &adev->dev;
659 	drvdata->atclk = devm_clk_get(&adev->dev, "atclk"); /* optional */
660 	if (!IS_ERR(drvdata->atclk)) {
661 		ret = clk_prepare_enable(drvdata->atclk);
662 		if (ret)
663 			return ret;
664 	}
665 	dev_set_drvdata(dev, drvdata);
666 
667 	/* validity for the resource is already checked by the AMBA core */
668 	base = devm_ioremap_resource(dev, res);
669 	if (IS_ERR(base))
670 		return PTR_ERR(base);
671 
672 	drvdata->base = base;
673 
674 	spin_lock_init(&drvdata->spinlock);
675 
676 	drvdata->buffer_depth = etb_get_buffer_depth(drvdata);
677 	pm_runtime_put(&adev->dev);
678 
679 	if (drvdata->buffer_depth & 0x80000000)
680 		return -EINVAL;
681 
682 	drvdata->buf = devm_kcalloc(dev,
683 				    drvdata->buffer_depth, 4, GFP_KERNEL);
684 	if (!drvdata->buf)
685 		return -ENOMEM;
686 
687 	desc.type = CORESIGHT_DEV_TYPE_SINK;
688 	desc.subtype.sink_subtype = CORESIGHT_DEV_SUBTYPE_SINK_BUFFER;
689 	desc.ops = &etb_cs_ops;
690 	desc.pdata = pdata;
691 	desc.dev = dev;
692 	desc.groups = coresight_etb_groups;
693 	drvdata->csdev = coresight_register(&desc);
694 	if (IS_ERR(drvdata->csdev))
695 		return PTR_ERR(drvdata->csdev);
696 
697 	drvdata->miscdev.name = pdata->name;
698 	drvdata->miscdev.minor = MISC_DYNAMIC_MINOR;
699 	drvdata->miscdev.fops = &etb_fops;
700 	ret = misc_register(&drvdata->miscdev);
701 	if (ret)
702 		goto err_misc_register;
703 
704 	return 0;
705 
706 err_misc_register:
707 	coresight_unregister(drvdata->csdev);
708 	return ret;
709 }
710 
711 #ifdef CONFIG_PM
712 static int etb_runtime_suspend(struct device *dev)
713 {
714 	struct etb_drvdata *drvdata = dev_get_drvdata(dev);
715 
716 	if (drvdata && !IS_ERR(drvdata->atclk))
717 		clk_disable_unprepare(drvdata->atclk);
718 
719 	return 0;
720 }
721 
722 static int etb_runtime_resume(struct device *dev)
723 {
724 	struct etb_drvdata *drvdata = dev_get_drvdata(dev);
725 
726 	if (drvdata && !IS_ERR(drvdata->atclk))
727 		clk_prepare_enable(drvdata->atclk);
728 
729 	return 0;
730 }
731 #endif
732 
733 static const struct dev_pm_ops etb_dev_pm_ops = {
734 	SET_RUNTIME_PM_OPS(etb_runtime_suspend, etb_runtime_resume, NULL)
735 };
736 
737 static const struct amba_id etb_ids[] = {
738 	{
739 		.id	= 0x000bb907,
740 		.mask	= 0x000fffff,
741 	},
742 	{ 0, 0},
743 };
744 
745 static struct amba_driver etb_driver = {
746 	.drv = {
747 		.name	= "coresight-etb10",
748 		.owner	= THIS_MODULE,
749 		.pm	= &etb_dev_pm_ops,
750 		.suppress_bind_attrs = true,
751 
752 	},
753 	.probe		= etb_probe,
754 	.id_table	= etb_ids,
755 };
756 builtin_amba_driver(etb_driver);
757