drivers/coresight/coresight-etb.c - kernel/msm - Git at Google

 /* Copyright (c) 2011-2012, The Linux Foundation. All rights reserved.
  *
  * 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 <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/init.h>
 #include <linux/types.h>
 #include <linux/device.h>
 #include <linux/platform_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/delay.h>
 #include <linux/spinlock.h>
 #include <linux/clk.h>
 #include <linux/of_coresight.h>
 #include <linux/coresight.h>

 #include "coresight-priv.h"

 #define etb_writel(drvdata, val, off)	__raw_writel((val), drvdata->base + off)
 #define etb_readl(drvdata, off)		__raw_readl(drvdata->base + off)

 #define ETB_LOCK(drvdata)						\
 do {									\
 	mb();								\
 	etb_writel(drvdata, 0x0, CORESIGHT_LAR);			\
 } while (0)
 #define ETB_UNLOCK(drvdata)						\
 do {									\
 	etb_writel(drvdata, CORESIGHT_UNLOCK, CORESIGHT_LAR);		\
 	mb();								\
 } while (0)

 #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)

 #define BYTES_PER_WORD		4
 #define ETB_SIZE_WORDS		4096
 #define FRAME_SIZE_WORDS	4

 struct etb_drvdata {
 	void __iomem		*base;
 	struct device		*dev;
 	struct coresight_device	*csdev;
 	struct miscdevice	miscdev;
 	struct clk		*clk;
 	spinlock_t		spinlock;
 	bool			reading;
 	atomic_t		in_use;
 	uint8_t			*buf;
 	bool			enable;
 	uint32_t		trigger_cntr;
 };

 static void __etb_enable(struct etb_drvdata *drvdata)
 {
 	int i;

 	ETB_UNLOCK(drvdata);

 	etb_writel(drvdata, 0x0, ETB_RAM_WRITE_POINTER);
 	for (i = 0; i < ETB_SIZE_WORDS; i++)
 		etb_writel(drvdata, 0x0, ETB_RWD_REG);

 	etb_writel(drvdata, 0x0, ETB_RAM_WRITE_POINTER);
 	etb_writel(drvdata, 0x0, ETB_RAM_READ_POINTER);

 	etb_writel(drvdata, drvdata->trigger_cntr, ETB_TRG);
 	etb_writel(drvdata, BIT(13) | BIT(0), ETB_FFCR);
 	etb_writel(drvdata, BIT(0), ETB_CTL_REG);

 	ETB_LOCK(drvdata);
 }

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

 	ret = clk_prepare_enable(drvdata->clk);
 	if (ret)
 		return ret;

 	spin_lock_irqsave(&drvdata->spinlock, flags);
 	__etb_enable(drvdata);
 	drvdata->enable = true;
 	spin_unlock_irqrestore(&drvdata->spinlock, flags);

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

 static void __etb_disable(struct etb_drvdata *drvdata)
 {
 	int count;
 	uint32_t ffcr;

 	ETB_UNLOCK(drvdata);

 	ffcr = etb_readl(drvdata, ETB_FFCR);
 	ffcr |= BIT(12);
 	etb_writel(drvdata, ffcr, ETB_FFCR);
 	ffcr |= BIT(6);
 	etb_writel(drvdata, ffcr, ETB_FFCR);
 	for (count = TIMEOUT_US; BVAL(etb_readl(drvdata, ETB_FFCR), 6) != 0
 				&& count > 0; count--)
 		udelay(1);
 	WARN(count == 0, "timeout while flushing DRVDATA, ETB_FFCR: %#x\n",
 	     etb_readl(drvdata, ETB_FFCR));

 	etb_writel(drvdata, 0x0, ETB_CTL_REG);
 	for (count = TIMEOUT_US; BVAL(etb_readl(drvdata, ETB_FFSR), 1) != 1
 				&& count > 0; count--)
 		udelay(1);
 	WARN(count == 0, "timeout while disabling DRVDATA, ETB_FFSR: %#x\n",
 	     etb_readl(drvdata, ETB_FFSR));

 	ETB_LOCK(drvdata);
 }

 static void __etb_dump(struct etb_drvdata *drvdata)
 {
 	int i;
 	uint8_t *buf_ptr;
 	uint32_t read_data;
 	uint32_t read_ptr;
 	uint32_t write_ptr;
 	uint32_t frame_off;
 	uint32_t frame_endoff;

 	ETB_UNLOCK(drvdata);

 	read_ptr = etb_readl(drvdata, ETB_RAM_READ_POINTER);
 	write_ptr = etb_readl(drvdata, ETB_RAM_WRITE_POINTER);

 	frame_off = write_ptr % FRAME_SIZE_WORDS;
 	frame_endoff = 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 ((etb_readl(drvdata, ETB_STATUS_REG) & BIT(0)) == 0)
 		etb_writel(drvdata, 0x0, ETB_RAM_READ_POINTER);
 	else
 		etb_writel(drvdata, write_ptr, ETB_RAM_READ_POINTER);

 	buf_ptr = drvdata->buf;
 	for (i = 0; i < ETB_SIZE_WORDS; i++) {
 		read_data = etb_readl(drvdata, 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 * BYTES_PER_WORD);
 		for (i = 0; i < frame_endoff; i++) {
 			*buf_ptr++ = 0x0;
 			*buf_ptr++ = 0x0;
 			*buf_ptr++ = 0x0;
 			*buf_ptr++ = 0x0;
 		}
 	}

 	etb_writel(drvdata, read_ptr, ETB_RAM_READ_POINTER);

 	ETB_LOCK(drvdata);
 }

 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(drvdata);
 	__etb_dump(drvdata);
 	drvdata->enable = false;
 	spin_unlock_irqrestore(&drvdata->spinlock, flags);

 	clk_disable_unprepare(drvdata->clk);

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

 static void etb_abort(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(drvdata);
 	__etb_dump(drvdata);
 	drvdata->enable = false;
 	spin_unlock_irqrestore(&drvdata->spinlock, flags);

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

 static const struct coresight_ops_sink etb_sink_ops = {
 	.enable		= etb_enable,
 	.disable	= etb_disable,
 	.abort		= etb_abort,
 };

 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 (drvdata->enable) {
 		__etb_disable(drvdata);
 		__etb_dump(drvdata);
 		__etb_enable(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 (atomic_cmpxchg(&drvdata->in_use, 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)
 {
 	struct etb_drvdata *drvdata = container_of(file->private_data,
 						   struct etb_drvdata, miscdev);

 	if (drvdata->reading == false) {
 		etb_dump(drvdata);
 		drvdata->reading = true;
 	}

 	if (*ppos + len > ETB_SIZE_WORDS * BYTES_PER_WORD)
 		len = ETB_SIZE_WORDS * BYTES_PER_WORD - *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: %d bytes copied, %d bytes left\n",
 		__func__, len, (int) (ETB_SIZE_WORDS * BYTES_PER_WORD - *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);

 	drvdata->reading = false;
 	atomic_set(&drvdata->in_use, 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 etb_show_trigger_cntr(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 scnprintf(buf, PAGE_SIZE, "%#lx\n", val);
 }

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

 	if (sscanf(buf, "%lx", &val) != 1)
 		return -EINVAL;

 	drvdata->trigger_cntr = val;
 	return size;
 }
 static DEVICE_ATTR(trigger_cntr, S_IRUGO | S_IWUSR, etb_show_trigger_cntr,
 		   etb_store_trigger_cntr);

 static struct attribute *etb_attrs[] = {
 	&dev_attr_trigger_cntr.attr,
 	NULL,
 };

 static struct attribute_group etb_attr_grp = {
 	.attrs = etb_attrs,
 };

 static const struct attribute_group *etb_attr_grps[] = {
 	&etb_attr_grp,
 	NULL,
 };

 static int __devinit etb_probe(struct platform_device *pdev)
 {
 	int ret;
 	struct device *dev = &pdev->dev;
 	struct coresight_platform_data *pdata;
 	struct etb_drvdata *drvdata;
 	struct resource *res;
 	struct coresight_desc *desc;

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

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

 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 	if (!res)
 		return -ENODEV;

 	drvdata->base = devm_ioremap(dev, res->start, resource_size(res));
 	if (!drvdata->base)
 		return -ENOMEM;

 	spin_lock_init(&drvdata->spinlock);

 	drvdata->clk = devm_clk_get(dev, "core_clk");
 	if (IS_ERR(drvdata->clk))
 		return PTR_ERR(drvdata->clk);

 	ret = clk_set_rate(drvdata->clk, CORESIGHT_CLK_RATE_TRACE);
 	if (ret)
 		return ret;

 	drvdata->buf = devm_kzalloc(dev, ETB_SIZE_WORDS * BYTES_PER_WORD,
 				    GFP_KERNEL);
 	if (!drvdata->buf)
 		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 = pdev->dev.platform_data;
 	desc->dev = &pdev->dev;
 	desc->groups = etb_attr_grps;
 	desc->owner = THIS_MODULE;
 	drvdata->csdev = coresight_register(desc);
 	if (IS_ERR(drvdata->csdev))
 		return PTR_ERR(drvdata->csdev);

 	drvdata->miscdev.name = ((struct coresight_platform_data *)
 				 (pdev->dev.platform_data))->name;
 	drvdata->miscdev.minor = MISC_DYNAMIC_MINOR;
 	drvdata->miscdev.fops = &etb_fops;
 	ret = misc_register(&drvdata->miscdev);
 	if (ret)
 		goto err;

 	dev_info(dev, "ETB initialized\n");
 	return 0;
 err:
 	coresight_unregister(drvdata->csdev);
 	return ret;
 }

 static int __devexit etb_remove(struct platform_device *pdev)
 {
 	struct etb_drvdata *drvdata = platform_get_drvdata(pdev);

 	misc_deregister(&drvdata->miscdev);
 	coresight_unregister(drvdata->csdev);
 	return 0;
 }

 static struct of_device_id etb_match[] = {
 	{.compatible = "arm,coresight-etb"},
 	{}
 };

 static struct platform_driver etb_driver = {
 	.probe          = etb_probe,
 	.remove         = __devexit_p(etb_remove),
 	.driver         = {
 		.name   = "coresight-etb",
 		.owner	= THIS_MODULE,
 		.of_match_table = etb_match,
 	},
 };

 static int __init etb_init(void)
 {
 	return platform_driver_register(&etb_driver);
 }
 module_init(etb_init);

 static void __exit etb_exit(void)
 {
 	platform_driver_unregister(&etb_driver);
 }
 module_exit(etb_exit);

 MODULE_LICENSE("GPL v2");
 MODULE_DESCRIPTION("CoreSight Embedded Trace Buffer driver");
	/* Copyright (c) 2011-2012, The Linux Foundation. All rights reserved.
	*
	* 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 <linux/kernel.h>
	#include <linux/module.h>
	#include <linux/init.h>
	#include <linux/types.h>
	#include <linux/device.h>
	#include <linux/platform_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/delay.h>
	#include <linux/spinlock.h>
	#include <linux/clk.h>
	#include <linux/of_coresight.h>
	#include <linux/coresight.h>

	#include "coresight-priv.h"

	#define etb_writel(drvdata, val, off) __raw_writel((val), drvdata->base + off)
	#define etb_readl(drvdata, off) __raw_readl(drvdata->base + off)

	#define ETB_LOCK(drvdata) \
	do { \
	mb(); \
	etb_writel(drvdata, 0x0, CORESIGHT_LAR); \
	} while (0)
	#define ETB_UNLOCK(drvdata) \
	do { \
	etb_writel(drvdata, CORESIGHT_UNLOCK, CORESIGHT_LAR); \
	mb(); \
	} while (0)

	#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)

	#define BYTES_PER_WORD 4
	#define ETB_SIZE_WORDS 4096
	#define FRAME_SIZE_WORDS 4

	struct etb_drvdata {
	void __iomem *base;
	struct device *dev;
	struct coresight_device *csdev;
	struct miscdevice miscdev;
	struct clk *clk;
	spinlock_t spinlock;
	bool reading;
	atomic_t in_use;
	uint8_t *buf;
	bool enable;
	uint32_t trigger_cntr;
	};

	static void __etb_enable(struct etb_drvdata *drvdata)
	{
	int i;

	ETB_UNLOCK(drvdata);

	etb_writel(drvdata, 0x0, ETB_RAM_WRITE_POINTER);
	for (i = 0; i < ETB_SIZE_WORDS; i++)
	etb_writel(drvdata, 0x0, ETB_RWD_REG);

	etb_writel(drvdata, 0x0, ETB_RAM_WRITE_POINTER);
	etb_writel(drvdata, 0x0, ETB_RAM_READ_POINTER);

	etb_writel(drvdata, drvdata->trigger_cntr, ETB_TRG);
	etb_writel(drvdata, BIT(13) \| BIT(0), ETB_FFCR);
	etb_writel(drvdata, BIT(0), ETB_CTL_REG);

	ETB_LOCK(drvdata);
	}

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

	ret = clk_prepare_enable(drvdata->clk);
	if (ret)
	return ret;

	spin_lock_irqsave(&drvdata->spinlock, flags);
	__etb_enable(drvdata);
	drvdata->enable = true;
	spin_unlock_irqrestore(&drvdata->spinlock, flags);

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

	static void __etb_disable(struct etb_drvdata *drvdata)
	{
	int count;
	uint32_t ffcr;

	ETB_UNLOCK(drvdata);

	ffcr = etb_readl(drvdata, ETB_FFCR);
	ffcr \|= BIT(12);
	etb_writel(drvdata, ffcr, ETB_FFCR);
	ffcr \|= BIT(6);
	etb_writel(drvdata, ffcr, ETB_FFCR);
	for (count = TIMEOUT_US; BVAL(etb_readl(drvdata, ETB_FFCR), 6) != 0
	&& count > 0; count--)
	udelay(1);
	WARN(count == 0, "timeout while flushing DRVDATA, ETB_FFCR: %#x\n",
	etb_readl(drvdata, ETB_FFCR));

	etb_writel(drvdata, 0x0, ETB_CTL_REG);
	for (count = TIMEOUT_US; BVAL(etb_readl(drvdata, ETB_FFSR), 1) != 1
	&& count > 0; count--)
	udelay(1);
	WARN(count == 0, "timeout while disabling DRVDATA, ETB_FFSR: %#x\n",
	etb_readl(drvdata, ETB_FFSR));

	ETB_LOCK(drvdata);
	}

	static void __etb_dump(struct etb_drvdata *drvdata)
	{
	int i;
	uint8_t *buf_ptr;
	uint32_t read_data;
	uint32_t read_ptr;
	uint32_t write_ptr;
	uint32_t frame_off;
	uint32_t frame_endoff;

	ETB_UNLOCK(drvdata);

	read_ptr = etb_readl(drvdata, ETB_RAM_READ_POINTER);
	write_ptr = etb_readl(drvdata, ETB_RAM_WRITE_POINTER);

	frame_off = write_ptr % FRAME_SIZE_WORDS;
	frame_endoff = 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 ((etb_readl(drvdata, ETB_STATUS_REG) & BIT(0)) == 0)
	etb_writel(drvdata, 0x0, ETB_RAM_READ_POINTER);
	else
	etb_writel(drvdata, write_ptr, ETB_RAM_READ_POINTER);

	buf_ptr = drvdata->buf;
	for (i = 0; i < ETB_SIZE_WORDS; i++) {
	read_data = etb_readl(drvdata, 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 * BYTES_PER_WORD);
	for (i = 0; i < frame_endoff; i++) {
	*buf_ptr++ = 0x0;
	*buf_ptr++ = 0x0;
	*buf_ptr++ = 0x0;
	*buf_ptr++ = 0x0;
	}
	}

	etb_writel(drvdata, read_ptr, ETB_RAM_READ_POINTER);

	ETB_LOCK(drvdata);
	}

	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(drvdata);
	__etb_dump(drvdata);
	drvdata->enable = false;
	spin_unlock_irqrestore(&drvdata->spinlock, flags);

	clk_disable_unprepare(drvdata->clk);

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

	static void etb_abort(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(drvdata);
	__etb_dump(drvdata);
	drvdata->enable = false;
	spin_unlock_irqrestore(&drvdata->spinlock, flags);

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

	static const struct coresight_ops_sink etb_sink_ops = {
	.enable = etb_enable,
	.disable = etb_disable,
	.abort = etb_abort,
	};

	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 (drvdata->enable) {
	__etb_disable(drvdata);
	__etb_dump(drvdata);
	__etb_enable(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 (atomic_cmpxchg(&drvdata->in_use, 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)
	{
	struct etb_drvdata *drvdata = container_of(file->private_data,
	struct etb_drvdata, miscdev);

	if (drvdata->reading == false) {
	etb_dump(drvdata);
	drvdata->reading = true;
	}

	if (ppos + len > ETB_SIZE_WORDS BYTES_PER_WORD)
	len = ETB_SIZE_WORDS * BYTES_PER_WORD - *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: %d bytes copied, %d bytes left\n",
	__func__, len, (int) (ETB_SIZE_WORDS * BYTES_PER_WORD - *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);

	drvdata->reading = false;
	atomic_set(&drvdata->in_use, 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 etb_show_trigger_cntr(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 scnprintf(buf, PAGE_SIZE, "%#lx\n", val);
	}

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

	if (sscanf(buf, "%lx", &val) != 1)
	return -EINVAL;

	drvdata->trigger_cntr = val;
	return size;
	}
	static DEVICE_ATTR(trigger_cntr, S_IRUGO \| S_IWUSR, etb_show_trigger_cntr,
	etb_store_trigger_cntr);

	static struct attribute *etb_attrs[] = {
	&dev_attr_trigger_cntr.attr,
	NULL,
	};

	static struct attribute_group etb_attr_grp = {
	.attrs = etb_attrs,
	};

	static const struct attribute_group *etb_attr_grps[] = {
	&etb_attr_grp,
	NULL,
	};

	static int __devinit etb_probe(struct platform_device *pdev)
	{
	int ret;
	struct device *dev = &pdev->dev;
	struct coresight_platform_data *pdata;
	struct etb_drvdata *drvdata;
	struct resource *res;
	struct coresight_desc *desc;

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

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

	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	if (!res)
	return -ENODEV;

	drvdata->base = devm_ioremap(dev, res->start, resource_size(res));
	if (!drvdata->base)
	return -ENOMEM;

	spin_lock_init(&drvdata->spinlock);

	drvdata->clk = devm_clk_get(dev, "core_clk");
	if (IS_ERR(drvdata->clk))
	return PTR_ERR(drvdata->clk);

	ret = clk_set_rate(drvdata->clk, CORESIGHT_CLK_RATE_TRACE);
	if (ret)
	return ret;

	drvdata->buf = devm_kzalloc(dev, ETB_SIZE_WORDS * BYTES_PER_WORD,
	GFP_KERNEL);
	if (!drvdata->buf)
	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 = pdev->dev.platform_data;
	desc->dev = &pdev->dev;
	desc->groups = etb_attr_grps;
	desc->owner = THIS_MODULE;
	drvdata->csdev = coresight_register(desc);
	if (IS_ERR(drvdata->csdev))
	return PTR_ERR(drvdata->csdev);

	drvdata->miscdev.name = ((struct coresight_platform_data *)
	(pdev->dev.platform_data))->name;
	drvdata->miscdev.minor = MISC_DYNAMIC_MINOR;
	drvdata->miscdev.fops = &etb_fops;
	ret = misc_register(&drvdata->miscdev);
	if (ret)
	goto err;

	dev_info(dev, "ETB initialized\n");
	return 0;
	err:
	coresight_unregister(drvdata->csdev);
	return ret;
	}

	static int __devexit etb_remove(struct platform_device *pdev)
	{
	struct etb_drvdata *drvdata = platform_get_drvdata(pdev);

	misc_deregister(&drvdata->miscdev);
	coresight_unregister(drvdata->csdev);
	return 0;
	}

	static struct of_device_id etb_match[] = {
	{.compatible = "arm,coresight-etb"},
	{}
	};

	static struct platform_driver etb_driver = {
	.probe = etb_probe,
	.remove = __devexit_p(etb_remove),
	.driver = {
	.name = "coresight-etb",
	.owner = THIS_MODULE,
	.of_match_table = etb_match,
	},
	};

	static int __init etb_init(void)
	{
	return platform_driver_register(&etb_driver);
	}
	module_init(etb_init);

	static void __exit etb_exit(void)
	{
	platform_driver_unregister(&etb_driver);
	}
	module_exit(etb_exit);

	MODULE_LICENSE("GPL v2");
	MODULE_DESCRIPTION("CoreSight Embedded Trace Buffer driver");