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

/* Copyright (c) 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/io.h>
#include <linux/err.h>
#include <linux/fs.h>
#include <linux/miscdevice.h>
#include <linux/uaccess.h>
#include <linux/slab.h>
#include <linux/dma-mapping.h>
#include <linux/spinlock.h>
#include <linux/clk.h>
#include <linux/of.h>
#include <linux/coresight.h>
#include <linux/amba/bus.h>

#include "coresight-priv.h"

#define TMC_RSZ			0x004
#define TMC_STS			0x00c
#define TMC_RRD			0x010
#define TMC_RRP			0x014
#define TMC_RWP			0x018
#define TMC_TRG			0x01c
#define TMC_CTL			0x020
#define TMC_RWD			0x024
#define TMC_MODE		0x028
#define TMC_LBUFLEVEL		0x02c
#define TMC_CBUFLEVEL		0x030
#define TMC_BUFWM		0x034
#define TMC_RRPHI		0x038
#define TMC_RWPHI		0x03c
#define TMC_AXICTL		0x110
#define TMC_DBALO		0x118
#define TMC_DBAHI		0x11c
#define TMC_FFSR		0x300
#define TMC_FFCR		0x304
#define TMC_PSCR		0x308
#define TMC_ITMISCOP0		0xee0
#define TMC_ITTRFLIN		0xee8
#define TMC_ITATBDATA0		0xeec
#define TMC_ITATBCTR2		0xef0
#define TMC_ITATBCTR1		0xef4
#define TMC_ITATBCTR0		0xef8

/* register description */
/* TMC_CTL - 0x020 */
#define TMC_CTL_CAPT_EN		BIT(0)
/* TMC_STS - 0x00C */
#define TMC_STS_TRIGGERED	BIT(1)
/* TMC_AXICTL - 0x110 */
#define TMC_AXICTL_PROT_CTL_B0	BIT(0)
#define TMC_AXICTL_PROT_CTL_B1	BIT(1)
#define TMC_AXICTL_SCT_GAT_MODE	BIT(7)
#define TMC_AXICTL_WR_BURST_LEN 0xF00
/* TMC_FFCR - 0x304 */
#define TMC_FFCR_EN_FMT		BIT(0)
#define TMC_FFCR_EN_TI		BIT(1)
#define TMC_FFCR_FON_FLIN	BIT(4)
#define TMC_FFCR_FON_TRIG_EVT	BIT(5)
#define TMC_FFCR_FLUSHMAN	BIT(6)
#define TMC_FFCR_TRIGON_TRIGIN	BIT(8)
#define TMC_FFCR_STOP_ON_FLUSH	BIT(12)

#define TMC_STS_TRIGGERED_BIT	2
#define TMC_FFCR_FLUSHMAN_BIT	6

enum tmc_config_type {
	TMC_CONFIG_TYPE_ETB,
	TMC_CONFIG_TYPE_ETR,
	TMC_CONFIG_TYPE_ETF,
};

enum tmc_mode {
	TMC_MODE_CIRCULAR_BUFFER,
	TMC_MODE_SOFTWARE_FIFO,
	TMC_MODE_HARDWARE_FIFO,
};

enum tmc_mem_intf_width {
	TMC_MEM_INTF_WIDTH_32BITS	= 0x2,
	TMC_MEM_INTF_WIDTH_64BITS	= 0x3,
	TMC_MEM_INTF_WIDTH_128BITS	= 0x4,
	TMC_MEM_INTF_WIDTH_256BITS	= 0x5,
};

/**
 * struct tmc_drvdata - specifics associated to an TMC component
 * @base:	memory mapped base address for this component.
 * @dev:	the device entity associated to this component.
 * @csdev:	component vitals needed by the framework.
 * @miscdev:	specifics to handle "/dev/xyz.tmc" entry.
 * @clk:	the clock this component is associated to.
 * @spinlock:	only one at a time pls.
 * @read_count:	manages preparation of buffer for reading.
 * @buf:	area of memory where trace data get sent.
 * @paddr:	DMA start location in RAM.
 * @vaddr:	virtual representation of @paddr.
 * @size:	@buf size.
 * @enable:	this TMC is being used.
 * @config_type: TMC variant, must be of type @tmc_config_type.
 * @trigger_cntr: amount of words to store after a trigger.
 */
struct tmc_drvdata {
	void __iomem		*base;
	struct device		*dev;
	struct coresight_device	*csdev;
	struct miscdevice	miscdev;
	struct clk		*clk;
	spinlock_t		spinlock;
	int			read_count;
	bool			reading;
	char			*buf;
	dma_addr_t		paddr;
	void __iomem		*vaddr;
	u32			size;
	bool			enable;
	enum tmc_config_type	config_type;
	u32			trigger_cntr;
};

static void tmc_wait_for_ready(struct tmc_drvdata *drvdata)
{
	/* Ensure formatter, unformatter and hardware fifo are empty */
	if (coresight_timeout(drvdata->base,
			      TMC_STS, TMC_STS_TRIGGERED_BIT, 1)) {
		dev_err(drvdata->dev,
			"timeout observed when probing at offset %#x\n",
			TMC_STS);
	}
}

static void tmc_flush_and_stop(struct tmc_drvdata *drvdata)
{
	u32 ffcr;

	ffcr = readl_relaxed(drvdata->base + TMC_FFCR);
	ffcr |= TMC_FFCR_STOP_ON_FLUSH;
	writel_relaxed(ffcr, drvdata->base + TMC_FFCR);
	ffcr |= TMC_FFCR_FLUSHMAN;
	writel_relaxed(ffcr, drvdata->base + TMC_FFCR);
	/* Ensure flush completes */
	if (coresight_timeout(drvdata->base,
			      TMC_FFCR, TMC_FFCR_FLUSHMAN_BIT, 0)) {
		dev_err(drvdata->dev,
			"timeout observed when probing at offset %#x\n",
			TMC_FFCR);
	}

	tmc_wait_for_ready(drvdata);
}

static void tmc_enable_hw(struct tmc_drvdata *drvdata)
{
	writel_relaxed(TMC_CTL_CAPT_EN, drvdata->base + TMC_CTL);
}

static void tmc_disable_hw(struct tmc_drvdata *drvdata)
{
	writel_relaxed(0x0, drvdata->base + TMC_CTL);
}

static void tmc_etb_enable_hw(struct tmc_drvdata *drvdata)
{
	/* Zero out the memory to help with debug */
	memset(drvdata->buf, 0, drvdata->size);

	CS_UNLOCK(drvdata->base);

	writel_relaxed(TMC_MODE_CIRCULAR_BUFFER, drvdata->base + TMC_MODE);
	writel_relaxed(TMC_FFCR_EN_FMT | TMC_FFCR_EN_TI |
		       TMC_FFCR_FON_FLIN | TMC_FFCR_FON_TRIG_EVT |
		       TMC_FFCR_TRIGON_TRIGIN,
		       drvdata->base + TMC_FFCR);

	writel_relaxed(drvdata->trigger_cntr, drvdata->base + TMC_TRG);
	tmc_enable_hw(drvdata);

	CS_LOCK(drvdata->base);
}

static void tmc_etr_enable_hw(struct tmc_drvdata *drvdata)
{
	u32 axictl;

	/* Zero out the memory to help with debug */
	memset(drvdata->vaddr, 0, drvdata->size);

	CS_UNLOCK(drvdata->base);

	writel_relaxed(drvdata->size / 4, drvdata->base + TMC_RSZ);
	writel_relaxed(TMC_MODE_CIRCULAR_BUFFER, drvdata->base + TMC_MODE);

	axictl = readl_relaxed(drvdata->base + TMC_AXICTL);
	axictl |= TMC_AXICTL_WR_BURST_LEN;
	writel_relaxed(axictl, drvdata->base + TMC_AXICTL);
	axictl &= ~TMC_AXICTL_SCT_GAT_MODE;
	writel_relaxed(axictl, drvdata->base + TMC_AXICTL);
	axictl = (axictl &
		  ~(TMC_AXICTL_PROT_CTL_B0 | TMC_AXICTL_PROT_CTL_B1)) |
		  TMC_AXICTL_PROT_CTL_B1;
	writel_relaxed(axictl, drvdata->base + TMC_AXICTL);

	writel_relaxed(drvdata->paddr, drvdata->base + TMC_DBALO);
	writel_relaxed(0x0, drvdata->base + TMC_DBAHI);
	writel_relaxed(TMC_FFCR_EN_FMT | TMC_FFCR_EN_TI |
		       TMC_FFCR_FON_FLIN | TMC_FFCR_FON_TRIG_EVT |
		       TMC_FFCR_TRIGON_TRIGIN,
		       drvdata->base + TMC_FFCR);
	writel_relaxed(drvdata->trigger_cntr, drvdata->base + TMC_TRG);
	tmc_enable_hw(drvdata);

	CS_LOCK(drvdata->base);
}

static void tmc_etf_enable_hw(struct tmc_drvdata *drvdata)
{
	CS_UNLOCK(drvdata->base);

	writel_relaxed(TMC_MODE_HARDWARE_FIFO, drvdata->base + TMC_MODE);
	writel_relaxed(TMC_FFCR_EN_FMT | TMC_FFCR_EN_TI,
		       drvdata->base + TMC_FFCR);
	writel_relaxed(0x0, drvdata->base + TMC_BUFWM);
	tmc_enable_hw(drvdata);

	CS_LOCK(drvdata->base);
}

static int tmc_enable(struct tmc_drvdata *drvdata, enum tmc_mode mode)
{
	int ret;
	unsigned long flags;

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

	spin_lock_irqsave(&drvdata->spinlock, flags);
	if (drvdata->reading) {
		spin_unlock_irqrestore(&drvdata->spinlock, flags);
		clk_disable_unprepare(drvdata->clk);
		return -EBUSY;
	}

	if (drvdata->config_type == TMC_CONFIG_TYPE_ETB) {
		tmc_etb_enable_hw(drvdata);
	} else if (drvdata->config_type == TMC_CONFIG_TYPE_ETR) {
		tmc_etr_enable_hw(drvdata);
	} else {
		if (mode == TMC_MODE_CIRCULAR_BUFFER)
			tmc_etb_enable_hw(drvdata);
		else
			tmc_etf_enable_hw(drvdata);
	}
	drvdata->enable = true;
	spin_unlock_irqrestore(&drvdata->spinlock, flags);

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

static int tmc_enable_sink(struct coresight_device *csdev)
{
	struct tmc_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);

	return tmc_enable(drvdata, TMC_MODE_CIRCULAR_BUFFER);
}

static int tmc_enable_link(struct coresight_device *csdev, int inport,
			   int outport)
{
	struct tmc_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);

	return tmc_enable(drvdata, TMC_MODE_HARDWARE_FIFO);
}

static void tmc_etb_dump_hw(struct tmc_drvdata *drvdata)
{
	enum tmc_mem_intf_width memwidth;
	u8 memwords;
	char *bufp;
	u32 read_data;
	int i;

	memwidth = BMVAL(readl_relaxed(drvdata->base + CORESIGHT_DEVID), 8, 10);
	if (memwidth == TMC_MEM_INTF_WIDTH_32BITS)
		memwords = 1;
	else if (memwidth == TMC_MEM_INTF_WIDTH_64BITS)
		memwords = 2;
	else if (memwidth == TMC_MEM_INTF_WIDTH_128BITS)
		memwords = 4;
	else
		memwords = 8;

	bufp = drvdata->buf;
	while (1) {
		for (i = 0; i < memwords; i++) {
			read_data = readl_relaxed(drvdata->base + TMC_RRD);
			if (read_data == 0xFFFFFFFF)
				return;
			memcpy(bufp, &read_data, 4);
			bufp += 4;
		}
	}
}

static void tmc_etb_disable_hw(struct tmc_drvdata *drvdata)
{
	CS_UNLOCK(drvdata->base);

	tmc_flush_and_stop(drvdata);
	tmc_etb_dump_hw(drvdata);
	tmc_disable_hw(drvdata);

	CS_LOCK(drvdata->base);
}

static void tmc_etr_dump_hw(struct tmc_drvdata *drvdata)
{
	u32 rwp, val;

	rwp = readl_relaxed(drvdata->base + TMC_RWP);
	val = readl_relaxed(drvdata->base + TMC_STS);

	/* How much memory do we still have */
	if (val & BIT(0))
		drvdata->buf = drvdata->vaddr + rwp - drvdata->paddr;
	else
		drvdata->buf = drvdata->vaddr;
}

static void tmc_etr_disable_hw(struct tmc_drvdata *drvdata)
{
	CS_UNLOCK(drvdata->base);

	tmc_flush_and_stop(drvdata);
	tmc_etr_dump_hw(drvdata);
	tmc_disable_hw(drvdata);

	CS_LOCK(drvdata->base);
}

static void tmc_etf_disable_hw(struct tmc_drvdata *drvdata)
{
	CS_UNLOCK(drvdata->base);

	tmc_flush_and_stop(drvdata);
	tmc_disable_hw(drvdata);

	CS_LOCK(drvdata->base);
}

static void tmc_disable(struct tmc_drvdata *drvdata, enum tmc_mode mode)
{
	unsigned long flags;

	spin_lock_irqsave(&drvdata->spinlock, flags);
	if (drvdata->reading)
		goto out;

	if (drvdata->config_type == TMC_CONFIG_TYPE_ETB) {
		tmc_etb_disable_hw(drvdata);
	} else if (drvdata->config_type == TMC_CONFIG_TYPE_ETR) {
		tmc_etr_disable_hw(drvdata);
	} else {
		if (mode == TMC_MODE_CIRCULAR_BUFFER)
			tmc_etb_disable_hw(drvdata);
		else
			tmc_etf_disable_hw(drvdata);
	}
out:
	drvdata->enable = false;
	spin_unlock_irqrestore(&drvdata->spinlock, flags);

	clk_disable_unprepare(drvdata->clk);

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

static void tmc_disable_sink(struct coresight_device *csdev)
{
	struct tmc_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);

	tmc_disable(drvdata, TMC_MODE_CIRCULAR_BUFFER);
}

static void tmc_disable_link(struct coresight_device *csdev, int inport,
			     int outport)
{
	struct tmc_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);

	tmc_disable(drvdata, TMC_MODE_HARDWARE_FIFO);
}

static const struct coresight_ops_sink tmc_sink_ops = {
	.enable		= tmc_enable_sink,
	.disable	= tmc_disable_sink,
};

static const struct coresight_ops_link tmc_link_ops = {
	.enable		= tmc_enable_link,
	.disable	= tmc_disable_link,
};

static const struct coresight_ops tmc_etb_cs_ops = {
	.sink_ops	= &tmc_sink_ops,
};

static const struct coresight_ops tmc_etr_cs_ops = {
	.sink_ops	= &tmc_sink_ops,
};

static const struct coresight_ops tmc_etf_cs_ops = {
	.sink_ops	= &tmc_sink_ops,
	.link_ops	= &tmc_link_ops,
};

static int tmc_read_prepare(struct tmc_drvdata *drvdata)
{
	int ret;
	unsigned long flags;
	enum tmc_mode mode;

	spin_lock_irqsave(&drvdata->spinlock, flags);
	if (!drvdata->enable)
		goto out;

	if (drvdata->config_type == TMC_CONFIG_TYPE_ETB) {
		tmc_etb_disable_hw(drvdata);
	} else if (drvdata->config_type == TMC_CONFIG_TYPE_ETR) {
		tmc_etr_disable_hw(drvdata);
	} else {
		mode = readl_relaxed(drvdata->base + TMC_MODE);
		if (mode == TMC_MODE_CIRCULAR_BUFFER) {
			tmc_etb_disable_hw(drvdata);
		} else {
			ret = -ENODEV;
			goto err;
		}
	}
out:
	drvdata->reading = true;
	spin_unlock_irqrestore(&drvdata->spinlock, flags);

	dev_info(drvdata->dev, "TMC read start\n");
	return 0;
err:
	spin_unlock_irqrestore(&drvdata->spinlock, flags);
	return ret;
}

static void tmc_read_unprepare(struct tmc_drvdata *drvdata)
{
	unsigned long flags;
	enum tmc_mode mode;

	spin_lock_irqsave(&drvdata->spinlock, flags);
	if (!drvdata->enable)
		goto out;

	if (drvdata->config_type == TMC_CONFIG_TYPE_ETB) {
		tmc_etb_enable_hw(drvdata);
	} else if (drvdata->config_type == TMC_CONFIG_TYPE_ETR) {
		tmc_etr_enable_hw(drvdata);
	} else {
		mode = readl_relaxed(drvdata->base + TMC_MODE);
		if (mode == TMC_MODE_CIRCULAR_BUFFER)
			tmc_etb_enable_hw(drvdata);
	}
out:
	drvdata->reading = false;
	spin_unlock_irqrestore(&drvdata->spinlock, flags);

	dev_info(drvdata->dev, "TMC read end\n");
}

static int tmc_open(struct inode *inode, struct file *file)
{
	struct tmc_drvdata *drvdata = container_of(file->private_data,
						   struct tmc_drvdata, miscdev);
	int ret = 0;

	if (drvdata->read_count++)
		goto out;

	ret = tmc_read_prepare(drvdata);
	if (ret)
		return ret;
out:
	nonseekable_open(inode, file);

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

static ssize_t tmc_read(struct file *file, char __user *data, size_t len,
			loff_t *ppos)
{
	struct tmc_drvdata *drvdata = container_of(file->private_data,
						   struct tmc_drvdata, miscdev);
	char *bufp = drvdata->buf + *ppos;

	if (*ppos + len > drvdata->size)
		len = drvdata->size - *ppos;

	if (drvdata->config_type == TMC_CONFIG_TYPE_ETR) {
		if (bufp == (char *)(drvdata->vaddr + drvdata->size))
			bufp = drvdata->vaddr;
		else if (bufp > (char *)(drvdata->vaddr + drvdata->size))
			bufp -= drvdata->size;
		if ((bufp + len) > (char *)(drvdata->vaddr + drvdata->size))
			len = (char *)(drvdata->vaddr + drvdata->size) - bufp;
	}

	if (copy_to_user(data, bufp, 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)(drvdata->size - *ppos));
	return len;
}

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

	if (--drvdata->read_count) {
		if (drvdata->read_count < 0) {
			dev_err(drvdata->dev, "mismatched close\n");
			drvdata->read_count = 0;
		}
		goto out;
	}

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

static const struct file_operations tmc_fops = {
	.owner		= THIS_MODULE,
	.open		= tmc_open,
	.read		= tmc_read,
	.release	= tmc_release,
	.llseek		= no_llseek,
};

static ssize_t status_show(struct device *dev,
			   struct device_attribute *attr, char *buf)
{
	int ret;
	unsigned long flags;
	u32 tmc_rsz, tmc_sts, tmc_rrp, tmc_rwp, tmc_trg;
	u32 tmc_ctl, tmc_ffsr, tmc_ffcr, tmc_mode, tmc_pscr;
	u32 devid;
	struct tmc_drvdata *drvdata = dev_get_drvdata(dev->parent);

	ret = clk_prepare_enable(drvdata->clk);
	if (ret)
		goto out;

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

	tmc_rsz = readl_relaxed(drvdata->base + TMC_RSZ);
	tmc_sts = readl_relaxed(drvdata->base + TMC_STS);
	tmc_rrp = readl_relaxed(drvdata->base + TMC_RRP);
	tmc_rwp = readl_relaxed(drvdata->base + TMC_RWP);
	tmc_trg = readl_relaxed(drvdata->base + TMC_TRG);
	tmc_ctl = readl_relaxed(drvdata->base + TMC_CTL);
	tmc_ffsr = readl_relaxed(drvdata->base + TMC_FFSR);
	tmc_ffcr = readl_relaxed(drvdata->base + TMC_FFCR);
	tmc_mode = readl_relaxed(drvdata->base + TMC_MODE);
	tmc_pscr = readl_relaxed(drvdata->base + TMC_PSCR);
	devid = readl_relaxed(drvdata->base + CORESIGHT_DEVID);

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

	clk_disable_unprepare(drvdata->clk);

	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"
		       "Mode:\t\t0x%x\n"
		       "PSRC:\t\t0x%x\n"
		       "DEVID:\t\t0x%x\n",
			tmc_rsz, tmc_sts, tmc_rrp, tmc_rwp, tmc_trg,
			tmc_ctl, tmc_ffsr, tmc_ffcr, tmc_mode, tmc_pscr, devid);
out:
	return -EINVAL;
}
static DEVICE_ATTR_RO(status);

static ssize_t trigger_cntr_show(struct device *dev,
			    struct device_attribute *attr, char *buf)
{
	struct tmc_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 tmc_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 struct attribute *coresight_etr_attrs[] = {
	&dev_attr_trigger_cntr.attr,
	&dev_attr_status.attr,
	NULL,
};
ATTRIBUTE_GROUPS(coresight_etr);

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

static int tmc_probe(struct amba_device *adev, const struct amba_id *id)
{
	int ret = 0;
	u32 devid;
	void __iomem *base;
	struct device *dev = &adev->dev;
	struct coresight_platform_data *pdata = NULL;
	struct tmc_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;
	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->clk = adev->pclk;
	ret = clk_prepare_enable(drvdata->clk);
	if (ret)
		return ret;

	devid = readl_relaxed(drvdata->base + CORESIGHT_DEVID);
	drvdata->config_type = BMVAL(devid, 6, 7);

	if (drvdata->config_type == TMC_CONFIG_TYPE_ETR) {
		if (np)
			ret = of_property_read_u32(np,
						   "arm,buffer-size",
						   &drvdata->size);
		if (ret)
			drvdata->size = SZ_1M;
	} else {
		drvdata->size = readl_relaxed(drvdata->base + TMC_RSZ) * 4;
	}

	clk_disable_unprepare(drvdata->clk);

	if (drvdata->config_type == TMC_CONFIG_TYPE_ETR) {
		drvdata->vaddr = dma_alloc_coherent(dev, drvdata->size,
						&drvdata->paddr, GFP_KERNEL);
		if (!drvdata->vaddr)
			return -ENOMEM;

		memset(drvdata->vaddr, 0, drvdata->size);
		drvdata->buf = drvdata->vaddr;
	} else {
		drvdata->buf = devm_kzalloc(dev, drvdata->size, GFP_KERNEL);
		if (!drvdata->buf)
			return -ENOMEM;
	}

	desc = devm_kzalloc(dev, sizeof(*desc), GFP_KERNEL);
	if (!desc) {
		ret = -ENOMEM;
		goto err_devm_kzalloc;
	}

	desc->pdata = pdata;
	desc->dev = dev;
	desc->subtype.sink_subtype = CORESIGHT_DEV_SUBTYPE_SINK_BUFFER;

	if (drvdata->config_type == TMC_CONFIG_TYPE_ETB) {
		desc->type = CORESIGHT_DEV_TYPE_SINK;
		desc->ops = &tmc_etb_cs_ops;
		desc->groups = coresight_etb_groups;
	} else if (drvdata->config_type == TMC_CONFIG_TYPE_ETR) {
		desc->type = CORESIGHT_DEV_TYPE_SINK;
		desc->ops = &tmc_etr_cs_ops;
		desc->groups = coresight_etr_groups;
	} else {
		desc->type = CORESIGHT_DEV_TYPE_LINKSINK;
		desc->subtype.link_subtype = CORESIGHT_DEV_SUBTYPE_LINK_FIFO;
		desc->ops = &tmc_etf_cs_ops;
		desc->groups = coresight_etf_groups;
	}

	drvdata->csdev = coresight_register(desc);
	if (IS_ERR(drvdata->csdev)) {
		ret = PTR_ERR(drvdata->csdev);
		goto err_devm_kzalloc;
	}

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

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

err_misc_register:
	coresight_unregister(drvdata->csdev);
err_devm_kzalloc:
	if (drvdata->config_type == TMC_CONFIG_TYPE_ETR)
		dma_free_coherent(dev, drvdata->size,
				&drvdata->paddr, GFP_KERNEL);
	return ret;
}

static int tmc_remove(struct amba_device *adev)
{
	struct tmc_drvdata *drvdata = amba_get_drvdata(adev);

	misc_deregister(&drvdata->miscdev);
	coresight_unregister(drvdata->csdev);
	if (drvdata->config_type == TMC_CONFIG_TYPE_ETR)
		dma_free_coherent(drvdata->dev, drvdata->size,
				  &drvdata->paddr, GFP_KERNEL);

	return 0;
}

static struct amba_id tmc_ids[] = {
	{
		.id     = 0x0003b961,
		.mask   = 0x0003ffff,
	},
	{ 0, 0},
};

static struct amba_driver tmc_driver = {
	.drv = {
		.name   = "coresight-tmc",
		.owner  = THIS_MODULE,
	},
	.probe		= tmc_probe,
	.remove		= tmc_remove,
	.id_table	= tmc_ids,
};

module_amba_driver(tmc_driver);

MODULE_LICENSE("GPL v2");
MODULE_DESCRIPTION("CoreSight Trace Memory Controller driver");