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 <linux/kernel.h>
9 #include <linux/init.h>
10 #include <linux/types.h>
11 #include <linux/device.h>
12 #include <linux/io.h>
13 #include <linux/err.h>
14 #include <linux/fs.h>
15 #include <linux/miscdevice.h>
16 #include <linux/uaccess.h>
17 #include <linux/slab.h>
18 #include <linux/spinlock.h>
19 #include <linux/pm_runtime.h>
20 #include <linux/seq_file.h>
21 #include <linux/coresight.h>
22 #include <linux/amba/bus.h>
23 #include <linux/clk.h>
24 #include <linux/circ_buf.h>
25 #include <linux/mm.h>
26 #include <linux/perf_event.h>
27 
28 
29 #include "coresight-priv.h"
30 #include "coresight-etm-perf.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  * @buf:	area of memory where ETB buffer content gets sent.
75  * @mode:	this ETB is being used.
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 	u8			*buf;
88 	u32			mode;
89 	u32			buffer_depth;
90 	u32			trigger_cntr;
91 };
92 
93 static int etb_set_buffer(struct coresight_device *csdev,
94 			  struct perf_output_handle *handle);
95 
96 static unsigned int etb_get_buffer_depth(struct etb_drvdata *drvdata)
97 {
98 	u32 depth = 0;
99 
100 	pm_runtime_get_sync(drvdata->dev);
101 
102 	/* RO registers don't need locking */
103 	depth = readl_relaxed(drvdata->base + ETB_RAM_DEPTH_REG);
104 
105 	pm_runtime_put(drvdata->dev);
106 	return depth;
107 }
108 
109 static void __etb_enable_hw(struct etb_drvdata *drvdata)
110 {
111 	int i;
112 	u32 depth;
113 
114 	CS_UNLOCK(drvdata->base);
115 
116 	depth = drvdata->buffer_depth;
117 	/* reset write RAM pointer address */
118 	writel_relaxed(0x0, drvdata->base + ETB_RAM_WRITE_POINTER);
119 	/* clear entire RAM buffer */
120 	for (i = 0; i < depth; i++)
121 		writel_relaxed(0x0, drvdata->base + ETB_RWD_REG);
122 
123 	/* reset write RAM pointer address */
124 	writel_relaxed(0x0, drvdata->base + ETB_RAM_WRITE_POINTER);
125 	/* reset read RAM pointer address */
126 	writel_relaxed(0x0, drvdata->base + ETB_RAM_READ_POINTER);
127 
128 	writel_relaxed(drvdata->trigger_cntr, drvdata->base + ETB_TRG);
129 	writel_relaxed(ETB_FFCR_EN_FTC | ETB_FFCR_STOP_TRIGGER,
130 		       drvdata->base + ETB_FFCR);
131 	/* ETB trace capture enable */
132 	writel_relaxed(ETB_CTL_CAPT_EN, drvdata->base + ETB_CTL_REG);
133 
134 	CS_LOCK(drvdata->base);
135 }
136 
137 static int etb_enable_hw(struct etb_drvdata *drvdata)
138 {
139 	int rc = coresight_claim_device(drvdata->base);
140 
141 	if (rc)
142 		return rc;
143 
144 	__etb_enable_hw(drvdata);
145 	return 0;
146 }
147 
148 static int etb_enable_sysfs(struct coresight_device *csdev)
149 {
150 	int ret = 0;
151 	unsigned long flags;
152 	struct etb_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);
153 
154 	spin_lock_irqsave(&drvdata->spinlock, flags);
155 
156 	/* Don't messup with perf sessions. */
157 	if (drvdata->mode == CS_MODE_PERF) {
158 		ret = -EBUSY;
159 		goto out;
160 	}
161 
162 	/* Nothing to do, the tracer is already enabled. */
163 	if (drvdata->mode == CS_MODE_SYSFS)
164 		goto out;
165 
166 	ret = etb_enable_hw(drvdata);
167 	if (!ret)
168 		drvdata->mode = CS_MODE_SYSFS;
169 
170 out:
171 	spin_unlock_irqrestore(&drvdata->spinlock, flags);
172 	return ret;
173 }
174 
175 static int etb_enable_perf(struct coresight_device *csdev, void *data)
176 {
177 	int ret = 0;
178 	unsigned long flags;
179 	struct etb_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);
180 
181 	spin_lock_irqsave(&drvdata->spinlock, flags);
182 
183 	/* No need to continue if the component is already in use. */
184 	if (drvdata->mode != CS_MODE_DISABLED) {
185 		ret = -EBUSY;
186 		goto out;
187 	}
188 
189 	/*
190 	 * We don't have an internal state to clean up if we fail to setup
191 	 * the perf buffer. So we can perform the step before we turn the
192 	 * ETB on and leave without cleaning up.
193 	 */
194 	ret = etb_set_buffer(csdev, (struct perf_output_handle *)data);
195 	if (ret)
196 		goto out;
197 
198 	ret = etb_enable_hw(drvdata);
199 	if (!ret)
200 		drvdata->mode = CS_MODE_PERF;
201 
202 out:
203 	spin_unlock_irqrestore(&drvdata->spinlock, flags);
204 	return ret;
205 }
206 
207 static int etb_enable(struct coresight_device *csdev, u32 mode, void *data)
208 {
209 	int ret;
210 	struct etb_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);
211 
212 	switch (mode) {
213 	case CS_MODE_SYSFS:
214 		ret = etb_enable_sysfs(csdev);
215 		break;
216 	case CS_MODE_PERF:
217 		ret = etb_enable_perf(csdev, data);
218 		break;
219 	default:
220 		ret = -EINVAL;
221 		break;
222 	}
223 
224 	if (ret)
225 		return ret;
226 
227 	dev_dbg(drvdata->dev, "ETB enabled\n");
228 	return 0;
229 }
230 
231 static void __etb_disable_hw(struct etb_drvdata *drvdata)
232 {
233 	u32 ffcr;
234 
235 	CS_UNLOCK(drvdata->base);
236 
237 	ffcr = readl_relaxed(drvdata->base + ETB_FFCR);
238 	/* stop formatter when a stop has completed */
239 	ffcr |= ETB_FFCR_STOP_FI;
240 	writel_relaxed(ffcr, drvdata->base + ETB_FFCR);
241 	/* manually generate a flush of the system */
242 	ffcr |= ETB_FFCR_FON_MAN;
243 	writel_relaxed(ffcr, drvdata->base + ETB_FFCR);
244 
245 	if (coresight_timeout(drvdata->base, ETB_FFCR, ETB_FFCR_BIT, 0)) {
246 		dev_err(drvdata->dev,
247 		"timeout while waiting for completion of Manual Flush\n");
248 	}
249 
250 	/* disable trace capture */
251 	writel_relaxed(0x0, drvdata->base + ETB_CTL_REG);
252 
253 	if (coresight_timeout(drvdata->base, ETB_FFSR, ETB_FFSR_BIT, 1)) {
254 		dev_err(drvdata->dev,
255 			"timeout while waiting for Formatter to Stop\n");
256 	}
257 
258 	CS_LOCK(drvdata->base);
259 }
260 
261 static void etb_dump_hw(struct etb_drvdata *drvdata)
262 {
263 	bool lost = false;
264 	int i;
265 	u8 *buf_ptr;
266 	u32 read_data, depth;
267 	u32 read_ptr, write_ptr;
268 	u32 frame_off, frame_endoff;
269 
270 	CS_UNLOCK(drvdata->base);
271 
272 	read_ptr = readl_relaxed(drvdata->base + ETB_RAM_READ_POINTER);
273 	write_ptr = readl_relaxed(drvdata->base + ETB_RAM_WRITE_POINTER);
274 
275 	frame_off = write_ptr % ETB_FRAME_SIZE_WORDS;
276 	frame_endoff = ETB_FRAME_SIZE_WORDS - frame_off;
277 	if (frame_off) {
278 		dev_err(drvdata->dev,
279 			"write_ptr: %lu not aligned to formatter frame size\n",
280 			(unsigned long)write_ptr);
281 		dev_err(drvdata->dev, "frameoff: %lu, frame_endoff: %lu\n",
282 			(unsigned long)frame_off, (unsigned long)frame_endoff);
283 		write_ptr += frame_endoff;
284 	}
285 
286 	if ((readl_relaxed(drvdata->base + ETB_STATUS_REG)
287 		      & ETB_STATUS_RAM_FULL) == 0) {
288 		writel_relaxed(0x0, drvdata->base + ETB_RAM_READ_POINTER);
289 	} else {
290 		writel_relaxed(write_ptr, drvdata->base + ETB_RAM_READ_POINTER);
291 		lost = true;
292 	}
293 
294 	depth = drvdata->buffer_depth;
295 	buf_ptr = drvdata->buf;
296 	for (i = 0; i < depth; i++) {
297 		read_data = readl_relaxed(drvdata->base +
298 					  ETB_RAM_READ_DATA_REG);
299 		*(u32 *)buf_ptr = read_data;
300 		buf_ptr += 4;
301 	}
302 
303 	if (lost)
304 		coresight_insert_barrier_packet(drvdata->buf);
305 
306 	if (frame_off) {
307 		buf_ptr -= (frame_endoff * 4);
308 		for (i = 0; i < frame_endoff; i++) {
309 			*buf_ptr++ = 0x0;
310 			*buf_ptr++ = 0x0;
311 			*buf_ptr++ = 0x0;
312 			*buf_ptr++ = 0x0;
313 		}
314 	}
315 
316 	writel_relaxed(read_ptr, drvdata->base + ETB_RAM_READ_POINTER);
317 
318 	CS_LOCK(drvdata->base);
319 }
320 
321 static void etb_disable_hw(struct etb_drvdata *drvdata)
322 {
323 	__etb_disable_hw(drvdata);
324 	etb_dump_hw(drvdata);
325 	coresight_disclaim_device(drvdata->base);
326 }
327 
328 static void etb_disable(struct coresight_device *csdev)
329 {
330 	struct etb_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);
331 	unsigned long flags;
332 
333 	spin_lock_irqsave(&drvdata->spinlock, flags);
334 
335 	/* Disable the ETB only if it needs to */
336 	if (drvdata->mode != CS_MODE_DISABLED) {
337 		etb_disable_hw(drvdata);
338 		drvdata->mode = CS_MODE_DISABLED;
339 	}
340 	spin_unlock_irqrestore(&drvdata->spinlock, flags);
341 
342 	dev_dbg(drvdata->dev, "ETB disabled\n");
343 }
344 
345 static void *etb_alloc_buffer(struct coresight_device *csdev, int cpu,
346 			      void **pages, int nr_pages, bool overwrite)
347 {
348 	int node;
349 	struct cs_buffers *buf;
350 
351 	if (cpu == -1)
352 		cpu = smp_processor_id();
353 	node = cpu_to_node(cpu);
354 
355 	buf = kzalloc_node(sizeof(struct cs_buffers), GFP_KERNEL, node);
356 	if (!buf)
357 		return NULL;
358 
359 	buf->snapshot = overwrite;
360 	buf->nr_pages = nr_pages;
361 	buf->data_pages = pages;
362 
363 	return buf;
364 }
365 
366 static void etb_free_buffer(void *config)
367 {
368 	struct cs_buffers *buf = config;
369 
370 	kfree(buf);
371 }
372 
373 static int etb_set_buffer(struct coresight_device *csdev,
374 			  struct perf_output_handle *handle)
375 {
376 	int ret = 0;
377 	unsigned long head;
378 	struct cs_buffers *buf = etm_perf_sink_config(handle);
379 
380 	if (!buf)
381 		return -EINVAL;
382 
383 	/* wrap head around to the amount of space we have */
384 	head = handle->head & ((buf->nr_pages << PAGE_SHIFT) - 1);
385 
386 	/* find the page to write to */
387 	buf->cur = head / PAGE_SIZE;
388 
389 	/* and offset within that page */
390 	buf->offset = head % PAGE_SIZE;
391 
392 	local_set(&buf->data_size, 0);
393 
394 	return ret;
395 }
396 
397 static unsigned long etb_update_buffer(struct coresight_device *csdev,
398 			      struct perf_output_handle *handle,
399 			      void *sink_config)
400 {
401 	bool lost = false;
402 	int i, cur;
403 	u8 *buf_ptr;
404 	const u32 *barrier;
405 	u32 read_ptr, write_ptr, capacity;
406 	u32 status, read_data;
407 	unsigned long offset, to_read;
408 	struct cs_buffers *buf = sink_config;
409 	struct etb_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);
410 
411 	if (!buf)
412 		return 0;
413 
414 	capacity = drvdata->buffer_depth * ETB_FRAME_SIZE_WORDS;
415 
416 	__etb_disable_hw(drvdata);
417 	CS_UNLOCK(drvdata->base);
418 
419 	/* unit is in words, not bytes */
420 	read_ptr = readl_relaxed(drvdata->base + ETB_RAM_READ_POINTER);
421 	write_ptr = readl_relaxed(drvdata->base + ETB_RAM_WRITE_POINTER);
422 
423 	/*
424 	 * Entries should be aligned to the frame size.  If they are not
425 	 * go back to the last alignment point to give decoding tools a
426 	 * chance to fix things.
427 	 */
428 	if (write_ptr % ETB_FRAME_SIZE_WORDS) {
429 		dev_err(drvdata->dev,
430 			"write_ptr: %lu not aligned to formatter frame size\n",
431 			(unsigned long)write_ptr);
432 
433 		write_ptr &= ~(ETB_FRAME_SIZE_WORDS - 1);
434 		lost = true;
435 	}
436 
437 	/*
438 	 * Get a hold of the status register and see if a wrap around
439 	 * has occurred.  If so adjust things accordingly.  Otherwise
440 	 * start at the beginning and go until the write pointer has
441 	 * been reached.
442 	 */
443 	status = readl_relaxed(drvdata->base + ETB_STATUS_REG);
444 	if (status & ETB_STATUS_RAM_FULL) {
445 		lost = true;
446 		to_read = capacity;
447 		read_ptr = write_ptr;
448 	} else {
449 		to_read = CIRC_CNT(write_ptr, read_ptr, drvdata->buffer_depth);
450 		to_read *= ETB_FRAME_SIZE_WORDS;
451 	}
452 
453 	/*
454 	 * Make sure we don't overwrite data that hasn't been consumed yet.
455 	 * It is entirely possible that the HW buffer has more data than the
456 	 * ring buffer can currently handle.  If so adjust the start address
457 	 * to take only the last traces.
458 	 *
459 	 * In snapshot mode we are looking to get the latest traces only and as
460 	 * such, we don't care about not overwriting data that hasn't been
461 	 * processed by user space.
462 	 */
463 	if (!buf->snapshot && to_read > handle->size) {
464 		u32 mask = ~(ETB_FRAME_SIZE_WORDS - 1);
465 
466 		/* The new read pointer must be frame size aligned */
467 		to_read = handle->size & mask;
468 		/*
469 		 * Move the RAM read pointer up, keeping in mind that
470 		 * everything is in frame size units.
471 		 */
472 		read_ptr = (write_ptr + drvdata->buffer_depth) -
473 					to_read / ETB_FRAME_SIZE_WORDS;
474 		/* Wrap around if need be*/
475 		if (read_ptr > (drvdata->buffer_depth - 1))
476 			read_ptr -= drvdata->buffer_depth;
477 		/* let the decoder know we've skipped ahead */
478 		lost = true;
479 	}
480 
481 	if (lost)
482 		perf_aux_output_flag(handle, PERF_AUX_FLAG_TRUNCATED);
483 
484 	/* finally tell HW where we want to start reading from */
485 	writel_relaxed(read_ptr, drvdata->base + ETB_RAM_READ_POINTER);
486 
487 	cur = buf->cur;
488 	offset = buf->offset;
489 	barrier = barrier_pkt;
490 
491 	for (i = 0; i < to_read; i += 4) {
492 		buf_ptr = buf->data_pages[cur] + offset;
493 		read_data = readl_relaxed(drvdata->base +
494 					  ETB_RAM_READ_DATA_REG);
495 		if (lost && i < CORESIGHT_BARRIER_PKT_SIZE) {
496 			read_data = *barrier;
497 			barrier++;
498 		}
499 
500 		*(u32 *)buf_ptr = read_data;
501 		buf_ptr += 4;
502 
503 		offset += 4;
504 		if (offset >= PAGE_SIZE) {
505 			offset = 0;
506 			cur++;
507 			/* wrap around at the end of the buffer */
508 			cur &= buf->nr_pages - 1;
509 		}
510 	}
511 
512 	/* reset ETB buffer for next run */
513 	writel_relaxed(0x0, drvdata->base + ETB_RAM_READ_POINTER);
514 	writel_relaxed(0x0, drvdata->base + ETB_RAM_WRITE_POINTER);
515 
516 	/*
517 	 * In snapshot mode we have to update the handle->head to point
518 	 * to the new location.
519 	 */
520 	if (buf->snapshot) {
521 		handle->head = (cur * PAGE_SIZE) + offset;
522 		to_read = buf->nr_pages << PAGE_SHIFT;
523 	}
524 	__etb_enable_hw(drvdata);
525 	CS_LOCK(drvdata->base);
526 
527 	return to_read;
528 }
529 
530 static const struct coresight_ops_sink etb_sink_ops = {
531 	.enable		= etb_enable,
532 	.disable	= etb_disable,
533 	.alloc_buffer	= etb_alloc_buffer,
534 	.free_buffer	= etb_free_buffer,
535 	.update_buffer	= etb_update_buffer,
536 };
537 
538 static const struct coresight_ops etb_cs_ops = {
539 	.sink_ops	= &etb_sink_ops,
540 };
541 
542 static void etb_dump(struct etb_drvdata *drvdata)
543 {
544 	unsigned long flags;
545 
546 	spin_lock_irqsave(&drvdata->spinlock, flags);
547 	if (drvdata->mode == CS_MODE_SYSFS) {
548 		__etb_disable_hw(drvdata);
549 		etb_dump_hw(drvdata);
550 		__etb_enable_hw(drvdata);
551 	}
552 	spin_unlock_irqrestore(&drvdata->spinlock, flags);
553 
554 	dev_dbg(drvdata->dev, "ETB dumped\n");
555 }
556 
557 static int etb_open(struct inode *inode, struct file *file)
558 {
559 	struct etb_drvdata *drvdata = container_of(file->private_data,
560 						   struct etb_drvdata, miscdev);
561 
562 	if (local_cmpxchg(&drvdata->reading, 0, 1))
563 		return -EBUSY;
564 
565 	dev_dbg(drvdata->dev, "%s: successfully opened\n", __func__);
566 	return 0;
567 }
568 
569 static ssize_t etb_read(struct file *file, char __user *data,
570 				size_t len, loff_t *ppos)
571 {
572 	u32 depth;
573 	struct etb_drvdata *drvdata = container_of(file->private_data,
574 						   struct etb_drvdata, miscdev);
575 
576 	etb_dump(drvdata);
577 
578 	depth = drvdata->buffer_depth;
579 	if (*ppos + len > depth * 4)
580 		len = depth * 4 - *ppos;
581 
582 	if (copy_to_user(data, drvdata->buf + *ppos, len)) {
583 		dev_dbg(drvdata->dev, "%s: copy_to_user failed\n", __func__);
584 		return -EFAULT;
585 	}
586 
587 	*ppos += len;
588 
589 	dev_dbg(drvdata->dev, "%s: %zu bytes copied, %d bytes left\n",
590 		__func__, len, (int)(depth * 4 - *ppos));
591 	return len;
592 }
593 
594 static int etb_release(struct inode *inode, struct file *file)
595 {
596 	struct etb_drvdata *drvdata = container_of(file->private_data,
597 						   struct etb_drvdata, miscdev);
598 	local_set(&drvdata->reading, 0);
599 
600 	dev_dbg(drvdata->dev, "%s: released\n", __func__);
601 	return 0;
602 }
603 
604 static const struct file_operations etb_fops = {
605 	.owner		= THIS_MODULE,
606 	.open		= etb_open,
607 	.read		= etb_read,
608 	.release	= etb_release,
609 	.llseek		= no_llseek,
610 };
611 
612 #define coresight_etb10_reg(name, offset)		\
613 	coresight_simple_reg32(struct etb_drvdata, name, offset)
614 
615 coresight_etb10_reg(rdp, ETB_RAM_DEPTH_REG);
616 coresight_etb10_reg(sts, ETB_STATUS_REG);
617 coresight_etb10_reg(rrp, ETB_RAM_READ_POINTER);
618 coresight_etb10_reg(rwp, ETB_RAM_WRITE_POINTER);
619 coresight_etb10_reg(trg, ETB_TRG);
620 coresight_etb10_reg(ctl, ETB_CTL_REG);
621 coresight_etb10_reg(ffsr, ETB_FFSR);
622 coresight_etb10_reg(ffcr, ETB_FFCR);
623 
624 static struct attribute *coresight_etb_mgmt_attrs[] = {
625 	&dev_attr_rdp.attr,
626 	&dev_attr_sts.attr,
627 	&dev_attr_rrp.attr,
628 	&dev_attr_rwp.attr,
629 	&dev_attr_trg.attr,
630 	&dev_attr_ctl.attr,
631 	&dev_attr_ffsr.attr,
632 	&dev_attr_ffcr.attr,
633 	NULL,
634 };
635 
636 static ssize_t trigger_cntr_show(struct device *dev,
637 			    struct device_attribute *attr, char *buf)
638 {
639 	struct etb_drvdata *drvdata = dev_get_drvdata(dev->parent);
640 	unsigned long val = drvdata->trigger_cntr;
641 
642 	return sprintf(buf, "%#lx\n", val);
643 }
644 
645 static ssize_t trigger_cntr_store(struct device *dev,
646 			     struct device_attribute *attr,
647 			     const char *buf, size_t size)
648 {
649 	int ret;
650 	unsigned long val;
651 	struct etb_drvdata *drvdata = dev_get_drvdata(dev->parent);
652 
653 	ret = kstrtoul(buf, 16, &val);
654 	if (ret)
655 		return ret;
656 
657 	drvdata->trigger_cntr = val;
658 	return size;
659 }
660 static DEVICE_ATTR_RW(trigger_cntr);
661 
662 static struct attribute *coresight_etb_attrs[] = {
663 	&dev_attr_trigger_cntr.attr,
664 	NULL,
665 };
666 
667 static const struct attribute_group coresight_etb_group = {
668 	.attrs = coresight_etb_attrs,
669 };
670 
671 static const struct attribute_group coresight_etb_mgmt_group = {
672 	.attrs = coresight_etb_mgmt_attrs,
673 	.name = "mgmt",
674 };
675 
676 const struct attribute_group *coresight_etb_groups[] = {
677 	&coresight_etb_group,
678 	&coresight_etb_mgmt_group,
679 	NULL,
680 };
681 
682 static int etb_probe(struct amba_device *adev, const struct amba_id *id)
683 {
684 	int ret;
685 	void __iomem *base;
686 	struct device *dev = &adev->dev;
687 	struct coresight_platform_data *pdata = NULL;
688 	struct etb_drvdata *drvdata;
689 	struct resource *res = &adev->res;
690 	struct coresight_desc desc = { 0 };
691 	struct device_node *np = adev->dev.of_node;
692 
693 	if (np) {
694 		pdata = of_get_coresight_platform_data(dev, np);
695 		if (IS_ERR(pdata))
696 			return PTR_ERR(pdata);
697 		adev->dev.platform_data = pdata;
698 	}
699 
700 	drvdata = devm_kzalloc(dev, sizeof(*drvdata), GFP_KERNEL);
701 	if (!drvdata)
702 		return -ENOMEM;
703 
704 	drvdata->dev = &adev->dev;
705 	drvdata->atclk = devm_clk_get(&adev->dev, "atclk"); /* optional */
706 	if (!IS_ERR(drvdata->atclk)) {
707 		ret = clk_prepare_enable(drvdata->atclk);
708 		if (ret)
709 			return ret;
710 	}
711 	dev_set_drvdata(dev, drvdata);
712 
713 	/* validity for the resource is already checked by the AMBA core */
714 	base = devm_ioremap_resource(dev, res);
715 	if (IS_ERR(base))
716 		return PTR_ERR(base);
717 
718 	drvdata->base = base;
719 
720 	spin_lock_init(&drvdata->spinlock);
721 
722 	drvdata->buffer_depth = etb_get_buffer_depth(drvdata);
723 	pm_runtime_put(&adev->dev);
724 
725 	if (drvdata->buffer_depth & 0x80000000)
726 		return -EINVAL;
727 
728 	drvdata->buf = devm_kcalloc(dev,
729 				    drvdata->buffer_depth, 4, GFP_KERNEL);
730 	if (!drvdata->buf)
731 		return -ENOMEM;
732 
733 	desc.type = CORESIGHT_DEV_TYPE_SINK;
734 	desc.subtype.sink_subtype = CORESIGHT_DEV_SUBTYPE_SINK_BUFFER;
735 	desc.ops = &etb_cs_ops;
736 	desc.pdata = pdata;
737 	desc.dev = dev;
738 	desc.groups = coresight_etb_groups;
739 	drvdata->csdev = coresight_register(&desc);
740 	if (IS_ERR(drvdata->csdev))
741 		return PTR_ERR(drvdata->csdev);
742 
743 	drvdata->miscdev.name = pdata->name;
744 	drvdata->miscdev.minor = MISC_DYNAMIC_MINOR;
745 	drvdata->miscdev.fops = &etb_fops;
746 	ret = misc_register(&drvdata->miscdev);
747 	if (ret)
748 		goto err_misc_register;
749 
750 	return 0;
751 
752 err_misc_register:
753 	coresight_unregister(drvdata->csdev);
754 	return ret;
755 }
756 
757 #ifdef CONFIG_PM
758 static int etb_runtime_suspend(struct device *dev)
759 {
760 	struct etb_drvdata *drvdata = dev_get_drvdata(dev);
761 
762 	if (drvdata && !IS_ERR(drvdata->atclk))
763 		clk_disable_unprepare(drvdata->atclk);
764 
765 	return 0;
766 }
767 
768 static int etb_runtime_resume(struct device *dev)
769 {
770 	struct etb_drvdata *drvdata = dev_get_drvdata(dev);
771 
772 	if (drvdata && !IS_ERR(drvdata->atclk))
773 		clk_prepare_enable(drvdata->atclk);
774 
775 	return 0;
776 }
777 #endif
778 
779 static const struct dev_pm_ops etb_dev_pm_ops = {
780 	SET_RUNTIME_PM_OPS(etb_runtime_suspend, etb_runtime_resume, NULL)
781 };
782 
783 static const struct amba_id etb_ids[] = {
784 	{
785 		.id	= 0x000bb907,
786 		.mask	= 0x000fffff,
787 	},
788 	{ 0, 0},
789 };
790 
791 static struct amba_driver etb_driver = {
792 	.drv = {
793 		.name	= "coresight-etb10",
794 		.owner	= THIS_MODULE,
795 		.pm	= &etb_dev_pm_ops,
796 		.suppress_bind_attrs = true,
797 
798 	},
799 	.probe		= etb_probe,
800 	.id_table	= etb_ids,
801 };
802 builtin_amba_driver(etb_driver);
803