1 /* Copyright (c) 2011-2012, The Linux Foundation. All rights reserved.
2  *
3  * Description: CoreSight Embedded Trace Buffer driver
4  *
5  * This program is free software; you can redistribute it and/or modify
6  * it under the terms of the GNU General Public License version 2 and
7  * only version 2 as published by the Free Software Foundation.
8  *
9  * This program is distributed in the hope that it will be useful,
10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
12  * GNU General Public License for more details.
13  */
14 
15 #include <asm/local.h>
16 #include <linux/kernel.h>
17 #include <linux/init.h>
18 #include <linux/types.h>
19 #include <linux/device.h>
20 #include <linux/io.h>
21 #include <linux/err.h>
22 #include <linux/fs.h>
23 #include <linux/miscdevice.h>
24 #include <linux/uaccess.h>
25 #include <linux/slab.h>
26 #include <linux/spinlock.h>
27 #include <linux/pm_runtime.h>
28 #include <linux/seq_file.h>
29 #include <linux/coresight.h>
30 #include <linux/amba/bus.h>
31 #include <linux/clk.h>
32 #include <linux/circ_buf.h>
33 #include <linux/mm.h>
34 #include <linux/perf_event.h>
35 
36 #include <asm/local.h>
37 
38 #include "coresight-priv.h"
39 
40 #define ETB_RAM_DEPTH_REG	0x004
41 #define ETB_STATUS_REG		0x00c
42 #define ETB_RAM_READ_DATA_REG	0x010
43 #define ETB_RAM_READ_POINTER	0x014
44 #define ETB_RAM_WRITE_POINTER	0x018
45 #define ETB_TRG			0x01c
46 #define ETB_CTL_REG		0x020
47 #define ETB_RWD_REG		0x024
48 #define ETB_FFSR		0x300
49 #define ETB_FFCR		0x304
50 #define ETB_ITMISCOP0		0xee0
51 #define ETB_ITTRFLINACK		0xee4
52 #define ETB_ITTRFLIN		0xee8
53 #define ETB_ITATBDATA0		0xeeC
54 #define ETB_ITATBCTR2		0xef0
55 #define ETB_ITATBCTR1		0xef4
56 #define ETB_ITATBCTR0		0xef8
57 
58 /* register description */
59 /* STS - 0x00C */
60 #define ETB_STATUS_RAM_FULL	BIT(0)
61 /* CTL - 0x020 */
62 #define ETB_CTL_CAPT_EN		BIT(0)
63 /* FFCR - 0x304 */
64 #define ETB_FFCR_EN_FTC		BIT(0)
65 #define ETB_FFCR_FON_MAN	BIT(6)
66 #define ETB_FFCR_STOP_FI	BIT(12)
67 #define ETB_FFCR_STOP_TRIGGER	BIT(13)
68 
69 #define ETB_FFCR_BIT		6
70 #define ETB_FFSR_BIT		1
71 #define ETB_FRAME_SIZE_WORDS	4
72 
73 /**
74  * struct etb_drvdata - specifics associated to an ETB component
75  * @base:	memory mapped base address for this component.
76  * @dev:	the device entity associated to this component.
77  * @atclk:	optional clock for the core parts of the ETB.
78  * @csdev:	component vitals needed by the framework.
79  * @miscdev:	specifics to handle "/dev/xyz.etb" entry.
80  * @spinlock:	only one at a time pls.
81  * @reading:	synchronise user space access to etb buffer.
82  * @mode:	this ETB is being used.
83  * @buf:	area of memory where ETB buffer content gets sent.
84  * @buffer_depth: size of @buf.
85  * @trigger_cntr: amount of words to store after a trigger.
86  */
87 struct etb_drvdata {
88 	void __iomem		*base;
89 	struct device		*dev;
90 	struct clk		*atclk;
91 	struct coresight_device	*csdev;
92 	struct miscdevice	miscdev;
93 	spinlock_t		spinlock;
94 	local_t			reading;
95 	local_t			mode;
96 	u8			*buf;
97 	u32			buffer_depth;
98 	u32			trigger_cntr;
99 };
100 
101 static unsigned int etb_get_buffer_depth(struct etb_drvdata *drvdata)
102 {
103 	u32 depth = 0;
104 
105 	pm_runtime_get_sync(drvdata->dev);
106 
107 	/* RO registers don't need locking */
108 	depth = readl_relaxed(drvdata->base + ETB_RAM_DEPTH_REG);
109 
110 	pm_runtime_put(drvdata->dev);
111 	return depth;
112 }
113 
114 static void etb_enable_hw(struct etb_drvdata *drvdata)
115 {
116 	int i;
117 	u32 depth;
118 
119 	CS_UNLOCK(drvdata->base);
120 
121 	depth = drvdata->buffer_depth;
122 	/* reset write RAM pointer address */
123 	writel_relaxed(0x0, drvdata->base + ETB_RAM_WRITE_POINTER);
124 	/* clear entire RAM buffer */
125 	for (i = 0; i < depth; i++)
126 		writel_relaxed(0x0, drvdata->base + ETB_RWD_REG);
127 
128 	/* reset write RAM pointer address */
129 	writel_relaxed(0x0, drvdata->base + ETB_RAM_WRITE_POINTER);
130 	/* reset read RAM pointer address */
131 	writel_relaxed(0x0, drvdata->base + ETB_RAM_READ_POINTER);
132 
133 	writel_relaxed(drvdata->trigger_cntr, drvdata->base + ETB_TRG);
134 	writel_relaxed(ETB_FFCR_EN_FTC | ETB_FFCR_STOP_TRIGGER,
135 		       drvdata->base + ETB_FFCR);
136 	/* ETB trace capture enable */
137 	writel_relaxed(ETB_CTL_CAPT_EN, drvdata->base + ETB_CTL_REG);
138 
139 	CS_LOCK(drvdata->base);
140 }
141 
142 static int etb_enable(struct coresight_device *csdev, u32 mode)
143 {
144 	u32 val;
145 	unsigned long flags;
146 	struct etb_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);
147 
148 	val = local_cmpxchg(&drvdata->mode,
149 			    CS_MODE_DISABLED, mode);
150 	/*
151 	 * When accessing from Perf, a HW buffer can be handled
152 	 * by a single trace entity.  In sysFS mode many tracers
153 	 * can be logging to the same HW buffer.
154 	 */
155 	if (val == CS_MODE_PERF)
156 		return -EBUSY;
157 
158 	/* Nothing to do, the tracer is already enabled. */
159 	if (val == CS_MODE_SYSFS)
160 		goto out;
161 
162 	spin_lock_irqsave(&drvdata->spinlock, flags);
163 	etb_enable_hw(drvdata);
164 	spin_unlock_irqrestore(&drvdata->spinlock, flags);
165 
166 out:
167 	dev_info(drvdata->dev, "ETB enabled\n");
168 	return 0;
169 }
170 
171 static void etb_disable_hw(struct etb_drvdata *drvdata)
172 {
173 	u32 ffcr;
174 
175 	CS_UNLOCK(drvdata->base);
176 
177 	ffcr = readl_relaxed(drvdata->base + ETB_FFCR);
178 	/* stop formatter when a stop has completed */
179 	ffcr |= ETB_FFCR_STOP_FI;
180 	writel_relaxed(ffcr, drvdata->base + ETB_FFCR);
181 	/* manually generate a flush of the system */
182 	ffcr |= ETB_FFCR_FON_MAN;
183 	writel_relaxed(ffcr, drvdata->base + ETB_FFCR);
184 
185 	if (coresight_timeout(drvdata->base, ETB_FFCR, ETB_FFCR_BIT, 0)) {
186 		dev_err(drvdata->dev,
187 		"timeout while waiting for completion of Manual Flush\n");
188 	}
189 
190 	/* disable trace capture */
191 	writel_relaxed(0x0, drvdata->base + ETB_CTL_REG);
192 
193 	if (coresight_timeout(drvdata->base, ETB_FFSR, ETB_FFSR_BIT, 1)) {
194 		dev_err(drvdata->dev,
195 			"timeout while waiting for Formatter to Stop\n");
196 	}
197 
198 	CS_LOCK(drvdata->base);
199 }
200 
201 static void etb_dump_hw(struct etb_drvdata *drvdata)
202 {
203 	int i;
204 	u8 *buf_ptr;
205 	u32 read_data, depth;
206 	u32 read_ptr, write_ptr;
207 	u32 frame_off, frame_endoff;
208 
209 	CS_UNLOCK(drvdata->base);
210 
211 	read_ptr = readl_relaxed(drvdata->base + ETB_RAM_READ_POINTER);
212 	write_ptr = readl_relaxed(drvdata->base + ETB_RAM_WRITE_POINTER);
213 
214 	frame_off = write_ptr % ETB_FRAME_SIZE_WORDS;
215 	frame_endoff = ETB_FRAME_SIZE_WORDS - frame_off;
216 	if (frame_off) {
217 		dev_err(drvdata->dev,
218 			"write_ptr: %lu not aligned to formatter frame size\n",
219 			(unsigned long)write_ptr);
220 		dev_err(drvdata->dev, "frameoff: %lu, frame_endoff: %lu\n",
221 			(unsigned long)frame_off, (unsigned long)frame_endoff);
222 		write_ptr += frame_endoff;
223 	}
224 
225 	if ((readl_relaxed(drvdata->base + ETB_STATUS_REG)
226 		      & ETB_STATUS_RAM_FULL) == 0)
227 		writel_relaxed(0x0, drvdata->base + ETB_RAM_READ_POINTER);
228 	else
229 		writel_relaxed(write_ptr, drvdata->base + ETB_RAM_READ_POINTER);
230 
231 	depth = drvdata->buffer_depth;
232 	buf_ptr = drvdata->buf;
233 	for (i = 0; i < depth; i++) {
234 		read_data = readl_relaxed(drvdata->base +
235 					  ETB_RAM_READ_DATA_REG);
236 		*buf_ptr++ = read_data >> 0;
237 		*buf_ptr++ = read_data >> 8;
238 		*buf_ptr++ = read_data >> 16;
239 		*buf_ptr++ = read_data >> 24;
240 	}
241 
242 	if (frame_off) {
243 		buf_ptr -= (frame_endoff * 4);
244 		for (i = 0; i < frame_endoff; i++) {
245 			*buf_ptr++ = 0x0;
246 			*buf_ptr++ = 0x0;
247 			*buf_ptr++ = 0x0;
248 			*buf_ptr++ = 0x0;
249 		}
250 	}
251 
252 	writel_relaxed(read_ptr, drvdata->base + ETB_RAM_READ_POINTER);
253 
254 	CS_LOCK(drvdata->base);
255 }
256 
257 static void etb_disable(struct coresight_device *csdev)
258 {
259 	struct etb_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);
260 	unsigned long flags;
261 
262 	spin_lock_irqsave(&drvdata->spinlock, flags);
263 	etb_disable_hw(drvdata);
264 	etb_dump_hw(drvdata);
265 	spin_unlock_irqrestore(&drvdata->spinlock, flags);
266 
267 	local_set(&drvdata->mode, CS_MODE_DISABLED);
268 
269 	dev_info(drvdata->dev, "ETB disabled\n");
270 }
271 
272 static void *etb_alloc_buffer(struct coresight_device *csdev, int cpu,
273 			      void **pages, int nr_pages, bool overwrite)
274 {
275 	int node;
276 	struct cs_buffers *buf;
277 
278 	if (cpu == -1)
279 		cpu = smp_processor_id();
280 	node = cpu_to_node(cpu);
281 
282 	buf = kzalloc_node(sizeof(struct cs_buffers), GFP_KERNEL, node);
283 	if (!buf)
284 		return NULL;
285 
286 	buf->snapshot = overwrite;
287 	buf->nr_pages = nr_pages;
288 	buf->data_pages = pages;
289 
290 	return buf;
291 }
292 
293 static void etb_free_buffer(void *config)
294 {
295 	struct cs_buffers *buf = config;
296 
297 	kfree(buf);
298 }
299 
300 static int etb_set_buffer(struct coresight_device *csdev,
301 			  struct perf_output_handle *handle,
302 			  void *sink_config)
303 {
304 	int ret = 0;
305 	unsigned long head;
306 	struct cs_buffers *buf = sink_config;
307 
308 	/* wrap head around to the amount of space we have */
309 	head = handle->head & ((buf->nr_pages << PAGE_SHIFT) - 1);
310 
311 	/* find the page to write to */
312 	buf->cur = head / PAGE_SIZE;
313 
314 	/* and offset within that page */
315 	buf->offset = head % PAGE_SIZE;
316 
317 	local_set(&buf->data_size, 0);
318 
319 	return ret;
320 }
321 
322 static unsigned long etb_reset_buffer(struct coresight_device *csdev,
323 				      struct perf_output_handle *handle,
324 				      void *sink_config, bool *lost)
325 {
326 	unsigned long size = 0;
327 	struct cs_buffers *buf = sink_config;
328 
329 	if (buf) {
330 		/*
331 		 * In snapshot mode ->data_size holds the new address of the
332 		 * ring buffer's head.  The size itself is the whole address
333 		 * range since we want the latest information.
334 		 */
335 		if (buf->snapshot)
336 			handle->head = local_xchg(&buf->data_size,
337 						  buf->nr_pages << PAGE_SHIFT);
338 
339 		/*
340 		 * Tell the tracer PMU how much we got in this run and if
341 		 * something went wrong along the way.  Nobody else can use
342 		 * this cs_buffers instance until we are done.  As such
343 		 * resetting parameters here and squaring off with the ring
344 		 * buffer API in the tracer PMU is fine.
345 		 */
346 		*lost = !!local_xchg(&buf->lost, 0);
347 		size = local_xchg(&buf->data_size, 0);
348 	}
349 
350 	return size;
351 }
352 
353 static void etb_update_buffer(struct coresight_device *csdev,
354 			      struct perf_output_handle *handle,
355 			      void *sink_config)
356 {
357 	int i, cur;
358 	u8 *buf_ptr;
359 	u32 read_ptr, write_ptr, capacity;
360 	u32 status, read_data, to_read;
361 	unsigned long offset;
362 	struct cs_buffers *buf = sink_config;
363 	struct etb_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);
364 
365 	if (!buf)
366 		return;
367 
368 	capacity = drvdata->buffer_depth * ETB_FRAME_SIZE_WORDS;
369 
370 	CS_UNLOCK(drvdata->base);
371 	etb_disable_hw(drvdata);
372 
373 	/* unit is in words, not bytes */
374 	read_ptr = readl_relaxed(drvdata->base + ETB_RAM_READ_POINTER);
375 	write_ptr = readl_relaxed(drvdata->base + ETB_RAM_WRITE_POINTER);
376 
377 	/*
378 	 * Entries should be aligned to the frame size.  If they are not
379 	 * go back to the last alignement point to give decoding tools a
380 	 * chance to fix things.
381 	 */
382 	if (write_ptr % ETB_FRAME_SIZE_WORDS) {
383 		dev_err(drvdata->dev,
384 			"write_ptr: %lu not aligned to formatter frame size\n",
385 			(unsigned long)write_ptr);
386 
387 		write_ptr &= ~(ETB_FRAME_SIZE_WORDS - 1);
388 		local_inc(&buf->lost);
389 	}
390 
391 	/*
392 	 * Get a hold of the status register and see if a wrap around
393 	 * has occurred.  If so adjust things accordingly.  Otherwise
394 	 * start at the beginning and go until the write pointer has
395 	 * been reached.
396 	 */
397 	status = readl_relaxed(drvdata->base + ETB_STATUS_REG);
398 	if (status & ETB_STATUS_RAM_FULL) {
399 		local_inc(&buf->lost);
400 		to_read = capacity;
401 		read_ptr = write_ptr;
402 	} else {
403 		to_read = CIRC_CNT(write_ptr, read_ptr, drvdata->buffer_depth);
404 		to_read *= ETB_FRAME_SIZE_WORDS;
405 	}
406 
407 	/*
408 	 * Make sure we don't overwrite data that hasn't been consumed yet.
409 	 * It is entirely possible that the HW buffer has more data than the
410 	 * ring buffer can currently handle.  If so adjust the start address
411 	 * to take only the last traces.
412 	 *
413 	 * In snapshot mode we are looking to get the latest traces only and as
414 	 * such, we don't care about not overwriting data that hasn't been
415 	 * processed by user space.
416 	 */
417 	if (!buf->snapshot && to_read > handle->size) {
418 		u32 mask = ~(ETB_FRAME_SIZE_WORDS - 1);
419 
420 		/* The new read pointer must be frame size aligned */
421 		to_read = handle->size & mask;
422 		/*
423 		 * Move the RAM read pointer up, keeping in mind that
424 		 * everything is in frame size units.
425 		 */
426 		read_ptr = (write_ptr + drvdata->buffer_depth) -
427 					to_read / ETB_FRAME_SIZE_WORDS;
428 		/* Wrap around if need be*/
429 		if (read_ptr > (drvdata->buffer_depth - 1))
430 			read_ptr -= drvdata->buffer_depth;
431 		/* let the decoder know we've skipped ahead */
432 		local_inc(&buf->lost);
433 	}
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 	for (i = 0; i < to_read; i += 4) {
441 		buf_ptr = buf->data_pages[cur] + offset;
442 		read_data = readl_relaxed(drvdata->base +
443 					  ETB_RAM_READ_DATA_REG);
444 		*buf_ptr++ = read_data >> 0;
445 		*buf_ptr++ = read_data >> 8;
446 		*buf_ptr++ = read_data >> 16;
447 		*buf_ptr++ = read_data >> 24;
448 
449 		offset += 4;
450 		if (offset >= PAGE_SIZE) {
451 			offset = 0;
452 			cur++;
453 			/* wrap around at the end of the buffer */
454 			cur &= buf->nr_pages - 1;
455 		}
456 	}
457 
458 	/* reset ETB buffer for next run */
459 	writel_relaxed(0x0, drvdata->base + ETB_RAM_READ_POINTER);
460 	writel_relaxed(0x0, drvdata->base + ETB_RAM_WRITE_POINTER);
461 
462 	/*
463 	 * In snapshot mode all we have to do is communicate to
464 	 * perf_aux_output_end() the address of the current head.  In full
465 	 * trace mode the same function expects a size to move rb->aux_head
466 	 * forward.
467 	 */
468 	if (buf->snapshot)
469 		local_set(&buf->data_size, (cur * PAGE_SIZE) + offset);
470 	else
471 		local_add(to_read, &buf->data_size);
472 
473 	etb_enable_hw(drvdata);
474 	CS_LOCK(drvdata->base);
475 }
476 
477 static const struct coresight_ops_sink etb_sink_ops = {
478 	.enable		= etb_enable,
479 	.disable	= etb_disable,
480 	.alloc_buffer	= etb_alloc_buffer,
481 	.free_buffer	= etb_free_buffer,
482 	.set_buffer	= etb_set_buffer,
483 	.reset_buffer	= etb_reset_buffer,
484 	.update_buffer	= etb_update_buffer,
485 };
486 
487 static const struct coresight_ops etb_cs_ops = {
488 	.sink_ops	= &etb_sink_ops,
489 };
490 
491 static void etb_dump(struct etb_drvdata *drvdata)
492 {
493 	unsigned long flags;
494 
495 	spin_lock_irqsave(&drvdata->spinlock, flags);
496 	if (local_read(&drvdata->mode) == CS_MODE_SYSFS) {
497 		etb_disable_hw(drvdata);
498 		etb_dump_hw(drvdata);
499 		etb_enable_hw(drvdata);
500 	}
501 	spin_unlock_irqrestore(&drvdata->spinlock, flags);
502 
503 	dev_info(drvdata->dev, "ETB dumped\n");
504 }
505 
506 static int etb_open(struct inode *inode, struct file *file)
507 {
508 	struct etb_drvdata *drvdata = container_of(file->private_data,
509 						   struct etb_drvdata, miscdev);
510 
511 	if (local_cmpxchg(&drvdata->reading, 0, 1))
512 		return -EBUSY;
513 
514 	dev_dbg(drvdata->dev, "%s: successfully opened\n", __func__);
515 	return 0;
516 }
517 
518 static ssize_t etb_read(struct file *file, char __user *data,
519 				size_t len, loff_t *ppos)
520 {
521 	u32 depth;
522 	struct etb_drvdata *drvdata = container_of(file->private_data,
523 						   struct etb_drvdata, miscdev);
524 
525 	etb_dump(drvdata);
526 
527 	depth = drvdata->buffer_depth;
528 	if (*ppos + len > depth * 4)
529 		len = depth * 4 - *ppos;
530 
531 	if (copy_to_user(data, drvdata->buf + *ppos, len)) {
532 		dev_dbg(drvdata->dev, "%s: copy_to_user failed\n", __func__);
533 		return -EFAULT;
534 	}
535 
536 	*ppos += len;
537 
538 	dev_dbg(drvdata->dev, "%s: %zu bytes copied, %d bytes left\n",
539 		__func__, len, (int)(depth * 4 - *ppos));
540 	return len;
541 }
542 
543 static int etb_release(struct inode *inode, struct file *file)
544 {
545 	struct etb_drvdata *drvdata = container_of(file->private_data,
546 						   struct etb_drvdata, miscdev);
547 	local_set(&drvdata->reading, 0);
548 
549 	dev_dbg(drvdata->dev, "%s: released\n", __func__);
550 	return 0;
551 }
552 
553 static const struct file_operations etb_fops = {
554 	.owner		= THIS_MODULE,
555 	.open		= etb_open,
556 	.read		= etb_read,
557 	.release	= etb_release,
558 	.llseek		= no_llseek,
559 };
560 
561 #define coresight_etb10_simple_func(name, offset)                       \
562 	coresight_simple_func(struct etb_drvdata, NULL, name, offset)
563 
564 coresight_etb10_simple_func(rdp, ETB_RAM_DEPTH_REG);
565 coresight_etb10_simple_func(sts, ETB_STATUS_REG);
566 coresight_etb10_simple_func(rrp, ETB_RAM_READ_POINTER);
567 coresight_etb10_simple_func(rwp, ETB_RAM_WRITE_POINTER);
568 coresight_etb10_simple_func(trg, ETB_TRG);
569 coresight_etb10_simple_func(ctl, ETB_CTL_REG);
570 coresight_etb10_simple_func(ffsr, ETB_FFSR);
571 coresight_etb10_simple_func(ffcr, ETB_FFCR);
572 
573 static struct attribute *coresight_etb_mgmt_attrs[] = {
574 	&dev_attr_rdp.attr,
575 	&dev_attr_sts.attr,
576 	&dev_attr_rrp.attr,
577 	&dev_attr_rwp.attr,
578 	&dev_attr_trg.attr,
579 	&dev_attr_ctl.attr,
580 	&dev_attr_ffsr.attr,
581 	&dev_attr_ffcr.attr,
582 	NULL,
583 };
584 
585 static ssize_t trigger_cntr_show(struct device *dev,
586 			    struct device_attribute *attr, char *buf)
587 {
588 	struct etb_drvdata *drvdata = dev_get_drvdata(dev->parent);
589 	unsigned long val = drvdata->trigger_cntr;
590 
591 	return sprintf(buf, "%#lx\n", val);
592 }
593 
594 static ssize_t trigger_cntr_store(struct device *dev,
595 			     struct device_attribute *attr,
596 			     const char *buf, size_t size)
597 {
598 	int ret;
599 	unsigned long val;
600 	struct etb_drvdata *drvdata = dev_get_drvdata(dev->parent);
601 
602 	ret = kstrtoul(buf, 16, &val);
603 	if (ret)
604 		return ret;
605 
606 	drvdata->trigger_cntr = val;
607 	return size;
608 }
609 static DEVICE_ATTR_RW(trigger_cntr);
610 
611 static struct attribute *coresight_etb_attrs[] = {
612 	&dev_attr_trigger_cntr.attr,
613 	NULL,
614 };
615 
616 static const struct attribute_group coresight_etb_group = {
617 	.attrs = coresight_etb_attrs,
618 };
619 
620 static const struct attribute_group coresight_etb_mgmt_group = {
621 	.attrs = coresight_etb_mgmt_attrs,
622 	.name = "mgmt",
623 };
624 
625 const struct attribute_group *coresight_etb_groups[] = {
626 	&coresight_etb_group,
627 	&coresight_etb_mgmt_group,
628 	NULL,
629 };
630 
631 static int etb_probe(struct amba_device *adev, const struct amba_id *id)
632 {
633 	int ret;
634 	void __iomem *base;
635 	struct device *dev = &adev->dev;
636 	struct coresight_platform_data *pdata = NULL;
637 	struct etb_drvdata *drvdata;
638 	struct resource *res = &adev->res;
639 	struct coresight_desc desc = { 0 };
640 	struct device_node *np = adev->dev.of_node;
641 
642 	if (np) {
643 		pdata = of_get_coresight_platform_data(dev, np);
644 		if (IS_ERR(pdata))
645 			return PTR_ERR(pdata);
646 		adev->dev.platform_data = pdata;
647 	}
648 
649 	drvdata = devm_kzalloc(dev, sizeof(*drvdata), GFP_KERNEL);
650 	if (!drvdata)
651 		return -ENOMEM;
652 
653 	drvdata->dev = &adev->dev;
654 	drvdata->atclk = devm_clk_get(&adev->dev, "atclk"); /* optional */
655 	if (!IS_ERR(drvdata->atclk)) {
656 		ret = clk_prepare_enable(drvdata->atclk);
657 		if (ret)
658 			return ret;
659 	}
660 	dev_set_drvdata(dev, drvdata);
661 
662 	/* validity for the resource is already checked by the AMBA core */
663 	base = devm_ioremap_resource(dev, res);
664 	if (IS_ERR(base))
665 		return PTR_ERR(base);
666 
667 	drvdata->base = base;
668 
669 	spin_lock_init(&drvdata->spinlock);
670 
671 	drvdata->buffer_depth = etb_get_buffer_depth(drvdata);
672 	pm_runtime_put(&adev->dev);
673 
674 	if (drvdata->buffer_depth & 0x80000000)
675 		return -EINVAL;
676 
677 	drvdata->buf = devm_kzalloc(dev,
678 				    drvdata->buffer_depth * 4, GFP_KERNEL);
679 	if (!drvdata->buf) {
680 		dev_err(dev, "Failed to allocate %u bytes for buffer data\n",
681 			drvdata->buffer_depth * 4);
682 		return -ENOMEM;
683 	}
684 
685 	desc.type = CORESIGHT_DEV_TYPE_SINK;
686 	desc.subtype.sink_subtype = CORESIGHT_DEV_SUBTYPE_SINK_BUFFER;
687 	desc.ops = &etb_cs_ops;
688 	desc.pdata = pdata;
689 	desc.dev = dev;
690 	desc.groups = coresight_etb_groups;
691 	drvdata->csdev = coresight_register(&desc);
692 	if (IS_ERR(drvdata->csdev))
693 		return PTR_ERR(drvdata->csdev);
694 
695 	drvdata->miscdev.name = pdata->name;
696 	drvdata->miscdev.minor = MISC_DYNAMIC_MINOR;
697 	drvdata->miscdev.fops = &etb_fops;
698 	ret = misc_register(&drvdata->miscdev);
699 	if (ret)
700 		goto err_misc_register;
701 
702 	return 0;
703 
704 err_misc_register:
705 	coresight_unregister(drvdata->csdev);
706 	return ret;
707 }
708 
709 #ifdef CONFIG_PM
710 static int etb_runtime_suspend(struct device *dev)
711 {
712 	struct etb_drvdata *drvdata = dev_get_drvdata(dev);
713 
714 	if (drvdata && !IS_ERR(drvdata->atclk))
715 		clk_disable_unprepare(drvdata->atclk);
716 
717 	return 0;
718 }
719 
720 static int etb_runtime_resume(struct device *dev)
721 {
722 	struct etb_drvdata *drvdata = dev_get_drvdata(dev);
723 
724 	if (drvdata && !IS_ERR(drvdata->atclk))
725 		clk_prepare_enable(drvdata->atclk);
726 
727 	return 0;
728 }
729 #endif
730 
731 static const struct dev_pm_ops etb_dev_pm_ops = {
732 	SET_RUNTIME_PM_OPS(etb_runtime_suspend, etb_runtime_resume, NULL)
733 };
734 
735 static struct amba_id etb_ids[] = {
736 	{
737 		.id	= 0x0003b907,
738 		.mask	= 0x0003ffff,
739 	},
740 	{ 0, 0},
741 };
742 
743 static struct amba_driver etb_driver = {
744 	.drv = {
745 		.name	= "coresight-etb10",
746 		.owner	= THIS_MODULE,
747 		.pm	= &etb_dev_pm_ops,
748 		.suppress_bind_attrs = true,
749 
750 	},
751 	.probe		= etb_probe,
752 	.id_table	= etb_ids,
753 };
754 builtin_amba_driver(etb_driver);
755