linux_kernel/drivers/hwtracing/coresight/coresight-etb10.c

/* Copyright (c) 2011-2012, The Linux Foundation. All rights reserved.
 *
 * Description: CoreSight Embedded Trace Buffer driver
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 and
 * only version 2 as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 */

#include <asm/local.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/types.h>
#include <linux/device.h>
#include <linux/io.h>
#include <linux/err.h>
#include <linux/fs.h>
#include <linux/miscdevice.h>
#include <linux/uaccess.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/pm_runtime.h>
#include <linux/seq_file.h>
#include <linux/coresight.h>
#include <linux/amba/bus.h>
#include <linux/clk.h>
#include <linux/circ_buf.h>
#include <linux/mm.h>
#include <linux/perf_event.h>

#include <asm/local.h>

#include "coresight-priv.h"

#define ETB_RAM_DEPTH_REG	0x004
#define ETB_STATUS_REG		0x00c
#define ETB_RAM_READ_DATA_REG	0x010
#define ETB_RAM_READ_POINTER	0x014
#define ETB_RAM_WRITE_POINTER	0x018
#define ETB_TRG			0x01c
#define ETB_CTL_REG		0x020
#define ETB_RWD_REG		0x024
#define ETB_FFSR		0x300
#define ETB_FFCR		0x304
#define ETB_ITMISCOP0		0xee0
#define ETB_ITTRFLINACK		0xee4
#define ETB_ITTRFLIN		0xee8
#define ETB_ITATBDATA0		0xeeC
#define ETB_ITATBCTR2		0xef0
#define ETB_ITATBCTR1		0xef4
#define ETB_ITATBCTR0		0xef8

/* register description */
/* STS - 0x00C */
#define ETB_STATUS_RAM_FULL	BIT(0)
/* CTL - 0x020 */
#define ETB_CTL_CAPT_EN		BIT(0)
/* FFCR - 0x304 */
#define ETB_FFCR_EN_FTC		BIT(0)
#define ETB_FFCR_FON_MAN	BIT(6)
#define ETB_FFCR_STOP_FI	BIT(12)
#define ETB_FFCR_STOP_TRIGGER	BIT(13)

#define ETB_FFCR_BIT		6
#define ETB_FFSR_BIT		1
#define ETB_FRAME_SIZE_WORDS	4

/**
 * struct cs_buffer - keep track of a recording session' specifics
 * @cur:	index of the current buffer
 * @nr_pages:	max number of pages granted to us
 * @offset:	offset within the current buffer
 * @data_size:	how much we collected in this run
 * @lost:	other than zero if we had a HW buffer wrap around
 * @snapshot:	is this run in snapshot mode
 * @data_pages:	a handle the ring buffer
 */
struct cs_buffers {
	unsigned int		cur;
	unsigned int		nr_pages;
	unsigned long		offset;
	local_t			data_size;
	local_t			lost;
	bool			snapshot;
	void			**data_pages;
};

/**
 * struct etb_drvdata - specifics associated to an ETB component
 * @base:	memory mapped base address for this component.
 * @dev:	the device entity associated to this component.
 * @atclk:	optional clock for the core parts of the ETB.
 * @csdev:	component vitals needed by the framework.
 * @miscdev:	specifics to handle "/dev/xyz.etb" entry.
 * @spinlock:	only one at a time pls.
 * @reading:	synchronise user space access to etb buffer.
 * @mode:	this ETB is being used.
 * @buf:	area of memory where ETB buffer content gets sent.
 * @buffer_depth: size of @buf.
 * @trigger_cntr: amount of words to store after a trigger.
 */
struct etb_drvdata {
	void __iomem		*base;
	struct device		*dev;
	struct clk		*atclk;
	struct coresight_device	*csdev;
	struct miscdevice	miscdev;
	spinlock_t		spinlock;
	local_t			reading;
	local_t			mode;
	u8			*buf;
	u32			buffer_depth;
	u32			trigger_cntr;
};

static unsigned int etb_get_buffer_depth(struct etb_drvdata *drvdata)
{
	u32 depth = 0;

	pm_runtime_get_sync(drvdata->dev);

	/* RO registers don't need locking */
	depth = readl_relaxed(drvdata->base + ETB_RAM_DEPTH_REG);

	pm_runtime_put(drvdata->dev);
	return depth;
}

static void etb_enable_hw(struct etb_drvdata *drvdata)
{
	int i;
	u32 depth;

	CS_UNLOCK(drvdata->base);

	depth = drvdata->buffer_depth;
	/* reset write RAM pointer address */
	writel_relaxed(0x0, drvdata->base + ETB_RAM_WRITE_POINTER);
	/* clear entire RAM buffer */
	for (i = 0; i < depth; i++)
		writel_relaxed(0x0, drvdata->base + ETB_RWD_REG);

	/* reset write RAM pointer address */
	writel_relaxed(0x0, drvdata->base + ETB_RAM_WRITE_POINTER);
	/* reset read RAM pointer address */
	writel_relaxed(0x0, drvdata->base + ETB_RAM_READ_POINTER);

	writel_relaxed(drvdata->trigger_cntr, drvdata->base + ETB_TRG);
	writel_relaxed(ETB_FFCR_EN_FTC | ETB_FFCR_STOP_TRIGGER,
		       drvdata->base + ETB_FFCR);
	/* ETB trace capture enable */
	writel_relaxed(ETB_CTL_CAPT_EN, drvdata->base + ETB_CTL_REG);

	CS_LOCK(drvdata->base);
}

static int etb_enable(struct coresight_device *csdev, u32 mode)
{
	u32 val;
	unsigned long flags;
	struct etb_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);

	val = local_cmpxchg(&drvdata->mode,
			    CS_MODE_DISABLED, mode);
	/*
	 * When accessing from Perf, a HW buffer can be handled
	 * by a single trace entity.  In sysFS mode many tracers
	 * can be logging to the same HW buffer.
	 */
	if (val == CS_MODE_PERF)
		return -EBUSY;

	/* Nothing to do, the tracer is already enabled. */
	if (val == CS_MODE_SYSFS)
		goto out;

	spin_lock_irqsave(&drvdata->spinlock, flags);
	etb_enable_hw(drvdata);
	spin_unlock_irqrestore(&drvdata->spinlock, flags);

out:
	dev_info(drvdata->dev, "ETB enabled\n");
	return 0;
}

static void etb_disable_hw(struct etb_drvdata *drvdata)
{
	u32 ffcr;

	CS_UNLOCK(drvdata->base);

	ffcr = readl_relaxed(drvdata->base + ETB_FFCR);
	/* stop formatter when a stop has completed */
	ffcr |= ETB_FFCR_STOP_FI;
	writel_relaxed(ffcr, drvdata->base + ETB_FFCR);
	/* manually generate a flush of the system */
	ffcr |= ETB_FFCR_FON_MAN;
	writel_relaxed(ffcr, drvdata->base + ETB_FFCR);

	if (coresight_timeout(drvdata->base, ETB_FFCR, ETB_FFCR_BIT, 0)) {
		dev_err(drvdata->dev,
			"timeout observed when probing at offset %#x\n",
			ETB_FFCR);
	}

	/* disable trace capture */
	writel_relaxed(0x0, drvdata->base + ETB_CTL_REG);

	if (coresight_timeout(drvdata->base, ETB_FFSR, ETB_FFSR_BIT, 1)) {
		dev_err(drvdata->dev,
			"timeout observed when probing at offset %#x\n",
			ETB_FFCR);
	}

	CS_LOCK(drvdata->base);
}

static void etb_dump_hw(struct etb_drvdata *drvdata)
{
	int i;
	u8 *buf_ptr;
	u32 read_data, depth;
	u32 read_ptr, write_ptr;
	u32 frame_off, frame_endoff;

	CS_UNLOCK(drvdata->base);

	read_ptr = readl_relaxed(drvdata->base + ETB_RAM_READ_POINTER);
	write_ptr = readl_relaxed(drvdata->base + ETB_RAM_WRITE_POINTER);

	frame_off = write_ptr % ETB_FRAME_SIZE_WORDS;
	frame_endoff = ETB_FRAME_SIZE_WORDS - frame_off;
	if (frame_off) {
		dev_err(drvdata->dev,
			"write_ptr: %lu not aligned to formatter frame size\n",
			(unsigned long)write_ptr);
		dev_err(drvdata->dev, "frameoff: %lu, frame_endoff: %lu\n",
			(unsigned long)frame_off, (unsigned long)frame_endoff);
		write_ptr += frame_endoff;
	}

	if ((readl_relaxed(drvdata->base + ETB_STATUS_REG)
		      & ETB_STATUS_RAM_FULL) == 0)
		writel_relaxed(0x0, drvdata->base + ETB_RAM_READ_POINTER);
	else
		writel_relaxed(write_ptr, drvdata->base + ETB_RAM_READ_POINTER);

	depth = drvdata->buffer_depth;
	buf_ptr = drvdata->buf;
	for (i = 0; i < depth; i++) {
		read_data = readl_relaxed(drvdata->base +
					  ETB_RAM_READ_DATA_REG);
		*buf_ptr++ = read_data >> 0;
		*buf_ptr++ = read_data >> 8;
		*buf_ptr++ = read_data >> 16;
		*buf_ptr++ = read_data >> 24;
	}

	if (frame_off) {
		buf_ptr -= (frame_endoff * 4);
		for (i = 0; i < frame_endoff; i++) {
			*buf_ptr++ = 0x0;
			*buf_ptr++ = 0x0;
			*buf_ptr++ = 0x0;
			*buf_ptr++ = 0x0;
		}
	}

	writel_relaxed(read_ptr, drvdata->base + ETB_RAM_READ_POINTER);

	CS_LOCK(drvdata->base);
}

static void etb_disable(struct coresight_device *csdev)
{
	struct etb_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);
	unsigned long flags;

	spin_lock_irqsave(&drvdata->spinlock, flags);
	etb_disable_hw(drvdata);
	etb_dump_hw(drvdata);
	spin_unlock_irqrestore(&drvdata->spinlock, flags);

	local_set(&drvdata->mode, CS_MODE_DISABLED);

	dev_info(drvdata->dev, "ETB disabled\n");
}

static void *etb_alloc_buffer(struct coresight_device *csdev, int cpu,
			      void **pages, int nr_pages, bool overwrite)
{
	int node;
	struct cs_buffers *buf;

	if (cpu == -1)
		cpu = smp_processor_id();
	node = cpu_to_node(cpu);

	buf = kzalloc_node(sizeof(struct cs_buffers), GFP_KERNEL, node);
	if (!buf)
		return NULL;

	buf->snapshot = overwrite;
	buf->nr_pages = nr_pages;
	buf->data_pages = pages;

	return buf;
}

static void etb_free_buffer(void *config)
{
	struct cs_buffers *buf = config;

	kfree(buf);
}

static int etb_set_buffer(struct coresight_device *csdev,
			  struct perf_output_handle *handle,
			  void *sink_config)
{
	int ret = 0;
	unsigned long head;
	struct cs_buffers *buf = sink_config;

	/* wrap head around to the amount of space we have */
	head = handle->head & ((buf->nr_pages << PAGE_SHIFT) - 1);

	/* find the page to write to */
	buf->cur = head / PAGE_SIZE;

	/* and offset within that page */
	buf->offset = head % PAGE_SIZE;

	local_set(&buf->data_size, 0);

	return ret;
}

static unsigned long etb_reset_buffer(struct coresight_device *csdev,
				      struct perf_output_handle *handle,
				      void *sink_config, bool *lost)
{
	unsigned long size = 0;
	struct cs_buffers *buf = sink_config;

	if (buf) {
		/*
		 * In snapshot mode ->data_size holds the new address of the
		 * ring buffer's head.  The size itself is the whole address
		 * range since we want the latest information.
		 */
		if (buf->snapshot)
			handle->head = local_xchg(&buf->data_size,
						  buf->nr_pages << PAGE_SHIFT);

		/*
		 * Tell the tracer PMU how much we got in this run and if
		 * something went wrong along the way.  Nobody else can use
		 * this cs_buffers instance until we are done.  As such
		 * resetting parameters here and squaring off with the ring
		 * buffer API in the tracer PMU is fine.
		 */
		*lost = !!local_xchg(&buf->lost, 0);
		size = local_xchg(&buf->data_size, 0);
	}

	return size;
}

static void etb_update_buffer(struct coresight_device *csdev,
			      struct perf_output_handle *handle,
			      void *sink_config)
{
	int i, cur;
	u8 *buf_ptr;
	u32 read_ptr, write_ptr, capacity;
	u32 status, read_data, to_read;
	unsigned long offset;
	struct cs_buffers *buf = sink_config;
	struct etb_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);

	if (!buf)
		return;

	capacity = drvdata->buffer_depth * ETB_FRAME_SIZE_WORDS;

	CS_UNLOCK(drvdata->base);
	etb_disable_hw(drvdata);

	/* unit is in words, not bytes */
	read_ptr = readl_relaxed(drvdata->base + ETB_RAM_READ_POINTER);
	write_ptr = readl_relaxed(drvdata->base + ETB_RAM_WRITE_POINTER);

	/*
	 * Entries should be aligned to the frame size.  If they are not
	 * go back to the last alignement point to give decoding tools a
	 * chance to fix things.
	 */
	if (write_ptr % ETB_FRAME_SIZE_WORDS) {
		dev_err(drvdata->dev,
			"write_ptr: %lu not aligned to formatter frame size\n",
			(unsigned long)write_ptr);

		write_ptr &= ~(ETB_FRAME_SIZE_WORDS - 1);
		local_inc(&buf->lost);
	}

	/*
	 * Get a hold of the status register and see if a wrap around
	 * has occurred.  If so adjust things accordingly.  Otherwise
	 * start at the beginning and go until the write pointer has
	 * been reached.
	 */
	status = readl_relaxed(drvdata->base + ETB_STATUS_REG);
	if (status & ETB_STATUS_RAM_FULL) {
		local_inc(&buf->lost);
		to_read = capacity;
		read_ptr = write_ptr;
	} else {
		to_read = CIRC_CNT(write_ptr, read_ptr, drvdata->buffer_depth);
		to_read *= ETB_FRAME_SIZE_WORDS;
	}

	/*
	 * Make sure we don't overwrite data that hasn't been consumed yet.
	 * It is entirely possible that the HW buffer has more data than the
	 * ring buffer can currently handle.  If so adjust the start address
	 * to take only the last traces.
	 *
	 * In snapshot mode we are looking to get the latest traces only and as
	 * such, we don't care about not overwriting data that hasn't been
	 * processed by user space.
	 */
	if (!buf->snapshot && to_read > handle->size) {
		u32 mask = ~(ETB_FRAME_SIZE_WORDS - 1);

		/* The new read pointer must be frame size aligned */
		to_read -= handle->size & mask;
		/*
		 * Move the RAM read pointer up, keeping in mind that
		 * everything is in frame size units.
		 */
		read_ptr = (write_ptr + drvdata->buffer_depth) -
					to_read / ETB_FRAME_SIZE_WORDS;
		/* Wrap around if need be*/
		read_ptr &= ~(drvdata->buffer_depth - 1);
		/* let the decoder know we've skipped ahead */
		local_inc(&buf->lost);
	}

	/* finally tell HW where we want to start reading from */
	writel_relaxed(read_ptr, drvdata->base + ETB_RAM_READ_POINTER);

	cur = buf->cur;
	offset = buf->offset;
	for (i = 0; i < to_read; i += 4) {
		buf_ptr = buf->data_pages[cur] + offset;
		read_data = readl_relaxed(drvdata->base +
					  ETB_RAM_READ_DATA_REG);
		*buf_ptr++ = read_data >> 0;
		*buf_ptr++ = read_data >> 8;
		*buf_ptr++ = read_data >> 16;
		*buf_ptr++ = read_data >> 24;

		offset += 4;
		if (offset >= PAGE_SIZE) {
			offset = 0;
			cur++;
			/* wrap around at the end of the buffer */
			cur &= buf->nr_pages - 1;
		}
	}

	/* reset ETB buffer for next run */
	writel_relaxed(0x0, drvdata->base + ETB_RAM_READ_POINTER);
	writel_relaxed(0x0, drvdata->base + ETB_RAM_WRITE_POINTER);

	/*
	 * In snapshot mode all we have to do is communicate to
	 * perf_aux_output_end() the address of the current head.  In full
	 * trace mode the same function expects a size to move rb->aux_head
	 * forward.
	 */
	if (buf->snapshot)
		local_set(&buf->data_size, (cur * PAGE_SIZE) + offset);
	else
		local_add(to_read, &buf->data_size);

	etb_enable_hw(drvdata);
	CS_LOCK(drvdata->base);
}

static const struct coresight_ops_sink etb_sink_ops = {
	.enable		= etb_enable,
	.disable	= etb_disable,
	.alloc_buffer	= etb_alloc_buffer,
	.free_buffer	= etb_free_buffer,
	.set_buffer	= etb_set_buffer,
	.reset_buffer	= etb_reset_buffer,
	.update_buffer	= etb_update_buffer,
};

static const struct coresight_ops etb_cs_ops = {
	.sink_ops	= &etb_sink_ops,
};

static void etb_dump(struct etb_drvdata *drvdata)
{
	unsigned long flags;

	spin_lock_irqsave(&drvdata->spinlock, flags);
	if (local_read(&drvdata->mode) == CS_MODE_SYSFS) {
		etb_disable_hw(drvdata);
		etb_dump_hw(drvdata);
		etb_enable_hw(drvdata);
	}
	spin_unlock_irqrestore(&drvdata->spinlock, flags);

	dev_info(drvdata->dev, "ETB dumped\n");
}

static int etb_open(struct inode *inode, struct file *file)
{
	struct etb_drvdata *drvdata = container_of(file->private_data,
						   struct etb_drvdata, miscdev);

	if (local_cmpxchg(&drvdata->reading, 0, 1))
		return -EBUSY;

	dev_dbg(drvdata->dev, "%s: successfully opened\n", __func__);
	return 0;
}

static ssize_t etb_read(struct file *file, char __user *data,
				size_t len, loff_t *ppos)
{
	u32 depth;
	struct etb_drvdata *drvdata = container_of(file->private_data,
						   struct etb_drvdata, miscdev);

	etb_dump(drvdata);

	depth = drvdata->buffer_depth;
	if (*ppos + len > depth * 4)
		len = depth * 4 - *ppos;

	if (copy_to_user(data, drvdata->buf + *ppos, len)) {
		dev_dbg(drvdata->dev, "%s: copy_to_user failed\n", __func__);
		return -EFAULT;
	}

	*ppos += len;

	dev_dbg(drvdata->dev, "%s: %zu bytes copied, %d bytes left\n",
		__func__, len, (int)(depth * 4 - *ppos));
	return len;
}

static int etb_release(struct inode *inode, struct file *file)
{
	struct etb_drvdata *drvdata = container_of(file->private_data,
						   struct etb_drvdata, miscdev);
	local_set(&drvdata->reading, 0);

	dev_dbg(drvdata->dev, "%s: released\n", __func__);
	return 0;
}

static const struct file_operations etb_fops = {
	.owner		= THIS_MODULE,
	.open		= etb_open,
	.read		= etb_read,
	.release	= etb_release,
	.llseek		= no_llseek,
};

static ssize_t status_show(struct device *dev,
			   struct device_attribute *attr, char *buf)
{
	unsigned long flags;
	u32 etb_rdr, etb_sr, etb_rrp, etb_rwp;
	u32 etb_trg, etb_cr, etb_ffsr, etb_ffcr;
	struct etb_drvdata *drvdata = dev_get_drvdata(dev->parent);

	pm_runtime_get_sync(drvdata->dev);
	spin_lock_irqsave(&drvdata->spinlock, flags);
	CS_UNLOCK(drvdata->base);

	etb_rdr = readl_relaxed(drvdata->base + ETB_RAM_DEPTH_REG);
	etb_sr = readl_relaxed(drvdata->base + ETB_STATUS_REG);
	etb_rrp = readl_relaxed(drvdata->base + ETB_RAM_READ_POINTER);
	etb_rwp = readl_relaxed(drvdata->base + ETB_RAM_WRITE_POINTER);
	etb_trg = readl_relaxed(drvdata->base + ETB_TRG);
	etb_cr = readl_relaxed(drvdata->base + ETB_CTL_REG);
	etb_ffsr = readl_relaxed(drvdata->base + ETB_FFSR);
	etb_ffcr = readl_relaxed(drvdata->base + ETB_FFCR);

	CS_LOCK(drvdata->base);
	spin_unlock_irqrestore(&drvdata->spinlock, flags);

	pm_runtime_put(drvdata->dev);

	return sprintf(buf,
		       "Depth:\t\t0x%x\n"
		       "Status:\t\t0x%x\n"
		       "RAM read ptr:\t0x%x\n"
		       "RAM wrt ptr:\t0x%x\n"
		       "Trigger cnt:\t0x%x\n"
		       "Control:\t0x%x\n"
		       "Flush status:\t0x%x\n"
		       "Flush ctrl:\t0x%x\n",
		       etb_rdr, etb_sr, etb_rrp, etb_rwp,
		       etb_trg, etb_cr, etb_ffsr, etb_ffcr);

	return -EINVAL;
}
static DEVICE_ATTR_RO(status);

static ssize_t trigger_cntr_show(struct device *dev,
			    struct device_attribute *attr, char *buf)
{
	struct etb_drvdata *drvdata = dev_get_drvdata(dev->parent);
	unsigned long val = drvdata->trigger_cntr;

	return sprintf(buf, "%#lx\n", val);
}

static ssize_t trigger_cntr_store(struct device *dev,
			     struct device_attribute *attr,
			     const char *buf, size_t size)
{
	int ret;
	unsigned long val;
	struct etb_drvdata *drvdata = dev_get_drvdata(dev->parent);

	ret = kstrtoul(buf, 16, &val);
	if (ret)
		return ret;

	drvdata->trigger_cntr = val;
	return size;
}
static DEVICE_ATTR_RW(trigger_cntr);

static struct attribute *coresight_etb_attrs[] = {
	&dev_attr_trigger_cntr.attr,
	&dev_attr_status.attr,
	NULL,
};
ATTRIBUTE_GROUPS(coresight_etb);

static int etb_probe(struct amba_device *adev, const struct amba_id *id)
{
	int ret;
	void __iomem *base;
	struct device *dev = &adev->dev;
	struct coresight_platform_data *pdata = NULL;
	struct etb_drvdata *drvdata;
	struct resource *res = &adev->res;
	struct coresight_desc *desc;
	struct device_node *np = adev->dev.of_node;

	if (np) {
		pdata = of_get_coresight_platform_data(dev, np);
		if (IS_ERR(pdata))
			return PTR_ERR(pdata);
		adev->dev.platform_data = pdata;
	}

	drvdata = devm_kzalloc(dev, sizeof(*drvdata), GFP_KERNEL);
	if (!drvdata)
		return -ENOMEM;

	drvdata->dev = &adev->dev;
	drvdata->atclk = devm_clk_get(&adev->dev, "atclk"); /* optional */
	if (!IS_ERR(drvdata->atclk)) {
		ret = clk_prepare_enable(drvdata->atclk);
		if (ret)
			return ret;
	}
	dev_set_drvdata(dev, drvdata);

	/* validity for the resource is already checked by the AMBA core */
	base = devm_ioremap_resource(dev, res);
	if (IS_ERR(base))
		return PTR_ERR(base);

	drvdata->base = base;

	spin_lock_init(&drvdata->spinlock);

	drvdata->buffer_depth = etb_get_buffer_depth(drvdata);
	pm_runtime_put(&adev->dev);

	if (drvdata->buffer_depth & 0x80000000)
		return -EINVAL;

	drvdata->buf = devm_kzalloc(dev,
				    drvdata->buffer_depth * 4, GFP_KERNEL);
	if (!drvdata->buf) {
		dev_err(dev, "Failed to allocate %u bytes for buffer data\n",
			drvdata->buffer_depth * 4);
		return -ENOMEM;
	}

	desc = devm_kzalloc(dev, sizeof(*desc), GFP_KERNEL);
	if (!desc)
		return -ENOMEM;

	desc->type = CORESIGHT_DEV_TYPE_SINK;
	desc->subtype.sink_subtype = CORESIGHT_DEV_SUBTYPE_SINK_BUFFER;
	desc->ops = &etb_cs_ops;
	desc->pdata = pdata;
	desc->dev = dev;
	desc->groups = coresight_etb_groups;
	drvdata->csdev = coresight_register(desc);
	if (IS_ERR(drvdata->csdev))
		return PTR_ERR(drvdata->csdev);

	drvdata->miscdev.name = pdata->name;
	drvdata->miscdev.minor = MISC_DYNAMIC_MINOR;
	drvdata->miscdev.fops = &etb_fops;
	ret = misc_register(&drvdata->miscdev);
	if (ret)
		goto err_misc_register;

	dev_info(dev, "ETB initialized\n");
	return 0;

err_misc_register:
	coresight_unregister(drvdata->csdev);
	return ret;
}

#ifdef CONFIG_PM
static int etb_runtime_suspend(struct device *dev)
{
	struct etb_drvdata *drvdata = dev_get_drvdata(dev);

	if (drvdata && !IS_ERR(drvdata->atclk))
		clk_disable_unprepare(drvdata->atclk);

	return 0;
}

static int etb_runtime_resume(struct device *dev)
{
	struct etb_drvdata *drvdata = dev_get_drvdata(dev);

	if (drvdata && !IS_ERR(drvdata->atclk))
		clk_prepare_enable(drvdata->atclk);

	return 0;
}
#endif

static const struct dev_pm_ops etb_dev_pm_ops = {
	SET_RUNTIME_PM_OPS(etb_runtime_suspend, etb_runtime_resume, NULL)
};

static struct amba_id etb_ids[] = {
	{
		.id	= 0x0003b907,
		.mask	= 0x0003ffff,
	},
	{ 0, 0},
};

static struct amba_driver etb_driver = {
	.drv = {
		.name	= "coresight-etb10",
		.owner	= THIS_MODULE,
		.pm	= &etb_dev_pm_ops,
		.suppress_bind_attrs = true,

	},
	.probe		= etb_probe,
	.id_table	= etb_ids,
};
builtin_amba_driver(etb_driver);