[RFC 2/8] coresight: add CoreSight TMC driver

[pratikp@codeaurora.org (pratikp at codeaurora.org)]

From: Pratik Patel <pratikp@codeaurora.org>

This driver manages CoreSight TMC (Trace Memory Controller) which
can act as a link or a sink depending upon its configuration. It
can present itself as an ETF (Embedded Trace FIFO) or ETR
(Embedded Trace Router).

ETF when configured in circular buffer mode acts as a trace
collection sink. When configured in HW fifo mode it acts as link.
ETR always acts as a sink and can be used to route data to memory
allocated in RAM.

Signed-off-by: Pratik Patel <pratikp@codeaurora.org>
---
 .../devicetree/bindings/arm/coresight.txt          |    2 +
 drivers/coresight/Kconfig                          |   11 +
 drivers/coresight/Makefile                         |    1 +
 drivers/coresight/coresight-tmc.c                  |  794 ++++++++++++++++++++
 4 files changed, 808 insertions(+), 0 deletions(-)
 create mode 100644 drivers/coresight/coresight-tmc.c

diff --git a/Documentation/devicetree/bindings/arm/coresight.txt b/Documentation/devicetree/bindings/arm/coresight.txt
index c584073..031f760 100644
--- a/Documentation/devicetree/bindings/arm/coresight.txt
+++ b/Documentation/devicetree/bindings/arm/coresight.txt
@@ -31,6 +31,7 @@ Optional properties:
 			 component
 - coresight-child-ports : list of input port numbers of the children
 - coresight-default-sink : represents the default compile time CoreSight sink
+- arm,buffer-size : size of contiguous buffer space for TMC ETR
 
 Examples:
 
@@ -43,6 +44,7 @@ Examples:
 		coresight-name = "coresight-tmc-etr";
 		coresight-nr-inports = <1>;
 		coresight-default-sink;
+		arm,buffer-size = <0x100000>;
 	};
 
 	tpiu: tpiu at fc318000 {
diff --git a/drivers/coresight/Kconfig b/drivers/coresight/Kconfig
index 65279c4..6905ef2 100644
--- a/drivers/coresight/Kconfig
+++ b/drivers/coresight/Kconfig
@@ -7,3 +7,14 @@ menuconfig CORESIGHT
 	  the right series of components on user input via sysfs. It also
 	  provides status information to user space applications through
 	  sysfs interface.
+
+if CORESIGHT
+
+config CORESIGHT_LINKS_AND_SINKS
+	bool "CoreSight Link and Sink drivers"
+	help
+	  This enables support for CoreSight link and sink drivers that are
+	  responsible for transporting and collecting the trace data
+	  respectively.
+
+endif
diff --git a/drivers/coresight/Makefile b/drivers/coresight/Makefile
index 218e3b5..16e26c5 100644
--- a/drivers/coresight/Makefile
+++ b/drivers/coresight/Makefile
@@ -3,3 +3,4 @@
 #
 obj-$(CONFIG_CORESIGHT) += coresight.o
 obj-$(CONFIG_OF) += of_coresight.o
+obj-$(CONFIG_CORESIGHT_LINKS_AND_SINKS) += coresight-tmc.o
diff --git a/drivers/coresight/coresight-tmc.c b/drivers/coresight/coresight-tmc.c
new file mode 100644
index 0000000..c1b7d31
--- /dev/null
+++ b/drivers/coresight/coresight-tmc.c
@@ -0,0 +1,794 @@
+/* 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/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/dma-mapping.h>
+#include <linux/delay.h>
+#include <linux/spinlock.h>
+#include <linux/clk.h>
+#include <linux/of.h>
+#include <linux/of_coresight.h>
+#include <linux/coresight.h>
+
+#include "coresight-priv.h"
+
+#define tmc_writel(drvdata, val, off)	__raw_writel((val), drvdata->base + off)
+#define tmc_readl(drvdata, off)		__raw_readl(drvdata->base + off)
+
+#define TMC_LOCK(drvdata)						\
+do {									\
+	mb();								\
+	tmc_writel(drvdata, 0x0, CORESIGHT_LAR);			\
+} while (0)
+#define TMC_UNLOCK(drvdata)						\
+do {									\
+	tmc_writel(drvdata, CORESIGHT_UNLOCK, CORESIGHT_LAR);		\
+	mb();								\
+} while (0)
+
+#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)
+
+#define BYTES_PER_WORD		4
+
+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 {
+	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;
+	uint32_t		size;
+	bool			enable;
+	enum tmc_config_type	config_type;
+	uint32_t		trigger_cntr;
+};
+
+static void tmc_wait_for_ready(struct tmc_drvdata *drvdata)
+{
+	int count;
+
+	/* Ensure formatter, unformatter and hardware fifo are empty */
+	for (count = TIMEOUT_US; BVAL(tmc_readl(drvdata, TMC_STS), 2) != 1
+				&& count > 0; count--)
+		udelay(1);
+	WARN(count == 0, "timeout while waiting for TMC ready, TMC_STS: %#x\n",
+	     tmc_readl(drvdata, TMC_STS));
+}
+
+static void tmc_flush_and_stop(struct tmc_drvdata *drvdata)
+{
+	int count;
+	uint32_t ffcr;
+
+	ffcr = tmc_readl(drvdata, TMC_FFCR);
+	ffcr |= BIT(12);
+	tmc_writel(drvdata, ffcr, TMC_FFCR);
+	ffcr |= BIT(6);
+	tmc_writel(drvdata, ffcr, TMC_FFCR);
+	/* Ensure flush completes */
+	for (count = TIMEOUT_US; BVAL(tmc_readl(drvdata, TMC_FFCR), 6) != 0
+				&& count > 0; count--)
+		udelay(1);
+	WARN(count == 0, "timeout while flushing TMC, TMC_FFCR: %#x\n",
+	     tmc_readl(drvdata, TMC_FFCR));
+
+	tmc_wait_for_ready(drvdata);
+}
+
+static void __tmc_enable(struct tmc_drvdata *drvdata)
+{
+	tmc_writel(drvdata, 0x1, TMC_CTL);
+}
+
+static void __tmc_disable(struct tmc_drvdata *drvdata)
+{
+	tmc_writel(drvdata, 0x0, TMC_CTL);
+}
+
+static void __tmc_etb_enable(struct tmc_drvdata *drvdata)
+{
+	/* Zero out the memory to help with debug */
+	memset(drvdata->buf, 0, drvdata->size);
+
+	TMC_UNLOCK(drvdata);
+
+	tmc_writel(drvdata, TMC_MODE_CIRCULAR_BUFFER, TMC_MODE);
+	tmc_writel(drvdata, 0x133, TMC_FFCR);
+	tmc_writel(drvdata, drvdata->trigger_cntr, TMC_TRG);
+	__tmc_enable(drvdata);
+
+	TMC_LOCK(drvdata);
+}
+
+static void __tmc_etr_enable(struct tmc_drvdata *drvdata)
+{
+	uint32_t axictl;
+
+	/* Zero out the memory to help with debug */
+	memset(drvdata->vaddr, 0, drvdata->size);
+
+	TMC_UNLOCK(drvdata);
+
+	tmc_writel(drvdata, drvdata->size / BYTES_PER_WORD, TMC_RSZ);
+	tmc_writel(drvdata, TMC_MODE_CIRCULAR_BUFFER, TMC_MODE);
+
+	axictl = tmc_readl(drvdata, TMC_AXICTL);
+	axictl |= (0xF << 8);
+	tmc_writel(drvdata, axictl, TMC_AXICTL);
+	axictl &= ~(0x1 << 7);
+	tmc_writel(drvdata, axictl, TMC_AXICTL);
+	axictl = (axictl & ~0x3) | 0x2;
+	tmc_writel(drvdata, axictl, TMC_AXICTL);
+
+	tmc_writel(drvdata, drvdata->paddr, TMC_DBALO);
+	tmc_writel(drvdata, 0x0, TMC_DBAHI);
+	tmc_writel(drvdata, 0x133, TMC_FFCR);
+	tmc_writel(drvdata, drvdata->trigger_cntr, TMC_TRG);
+	__tmc_enable(drvdata);
+
+	TMC_LOCK(drvdata);
+}
+
+static void __tmc_etf_enable(struct tmc_drvdata *drvdata)
+{
+	TMC_UNLOCK(drvdata);
+
+	tmc_writel(drvdata, TMC_MODE_HARDWARE_FIFO, TMC_MODE);
+	tmc_writel(drvdata, 0x3, TMC_FFCR);
+	tmc_writel(drvdata, 0x0, TMC_BUFWM);
+	__tmc_enable(drvdata);
+
+	TMC_LOCK(drvdata);
+}
+
+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(drvdata);
+	} else if (drvdata->config_type == TMC_CONFIG_TYPE_ETR) {
+		__tmc_etr_enable(drvdata);
+	} else {
+		if (mode == TMC_MODE_CIRCULAR_BUFFER)
+			__tmc_etb_enable(drvdata);
+		else
+			__tmc_etf_enable(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(struct tmc_drvdata *drvdata)
+{
+	enum tmc_mem_intf_width memwidth;
+	uint8_t memwords;
+	char *bufp;
+	uint32_t read_data;
+	int i;
+
+	memwidth = BMVAL(tmc_readl(drvdata, 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 = tmc_readl(drvdata, TMC_RRD);
+			if (read_data == 0xFFFFFFFF)
+				return;
+			memcpy(bufp, &read_data, BYTES_PER_WORD);
+			bufp += BYTES_PER_WORD;
+		}
+	}
+}
+
+static void __tmc_etb_disable(struct tmc_drvdata *drvdata)
+{
+	TMC_UNLOCK(drvdata);
+
+	tmc_flush_and_stop(drvdata);
+	__tmc_etb_dump(drvdata);
+	__tmc_disable(drvdata);
+
+	TMC_LOCK(drvdata);
+}
+
+static void __tmc_etr_dump(struct tmc_drvdata *drvdata)
+{
+	uint32_t rwp, rwphi;
+
+	rwp = tmc_readl(drvdata, TMC_RWP);
+	rwphi = tmc_readl(drvdata, TMC_RWPHI);
+
+	if (BVAL(tmc_readl(drvdata, TMC_STS), 0))
+		drvdata->buf = drvdata->vaddr + rwp - drvdata->paddr;
+	else
+		drvdata->buf = drvdata->vaddr;
+}
+
+static void __tmc_etr_disable(struct tmc_drvdata *drvdata)
+{
+	TMC_UNLOCK(drvdata);
+
+	tmc_flush_and_stop(drvdata);
+	__tmc_etr_dump(drvdata);
+	__tmc_disable(drvdata);
+
+	TMC_LOCK(drvdata);
+}
+
+static void __tmc_etf_disable(struct tmc_drvdata *drvdata)
+{
+	TMC_UNLOCK(drvdata);
+
+	tmc_flush_and_stop(drvdata);
+	__tmc_disable(drvdata);
+
+	TMC_LOCK(drvdata);
+}
+
+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(drvdata);
+	} else if (drvdata->config_type == TMC_CONFIG_TYPE_ETR) {
+		__tmc_etr_disable(drvdata);
+	} else {
+		if (mode == TMC_MODE_CIRCULAR_BUFFER)
+			__tmc_etb_disable(drvdata);
+		else
+			__tmc_etf_disable(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 void tmc_abort(struct coresight_device *csdev)
+{
+	struct tmc_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);
+	unsigned long flags;
+	enum tmc_mode mode;
+
+	spin_lock_irqsave(&drvdata->spinlock, flags);
+	if (drvdata->reading)
+		goto out0;
+
+	if (drvdata->config_type == TMC_CONFIG_TYPE_ETB) {
+		__tmc_etb_disable(drvdata);
+	} else if (drvdata->config_type == TMC_CONFIG_TYPE_ETR) {
+		__tmc_etr_disable(drvdata);
+	} else {
+		mode = tmc_readl(drvdata, TMC_MODE);
+		if (mode == TMC_MODE_CIRCULAR_BUFFER)
+			__tmc_etb_disable(drvdata);
+		else
+			goto out1;
+	}
+out0:
+	drvdata->enable = false;
+	spin_unlock_irqrestore(&drvdata->spinlock, flags);
+
+	dev_info(drvdata->dev, "TMC aborted\n");
+	return;
+out1:
+	spin_unlock_irqrestore(&drvdata->spinlock, flags);
+}
+
+static const struct coresight_ops_sink tmc_sink_ops = {
+	.enable		= tmc_enable_sink,
+	.disable	= tmc_disable_sink,
+	.abort		= tmc_abort,
+};
+
+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(drvdata);
+	} else if (drvdata->config_type == TMC_CONFIG_TYPE_ETR) {
+		__tmc_etr_disable(drvdata);
+	} else {
+		mode = tmc_readl(drvdata, TMC_MODE);
+		if (mode == TMC_MODE_CIRCULAR_BUFFER) {
+			__tmc_etb_disable(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(drvdata);
+	} else if (drvdata->config_type == TMC_CONFIG_TYPE_ETR) {
+		__tmc_etr_enable(drvdata);
+	} else {
+		mode = tmc_readl(drvdata, TMC_MODE);
+		if (mode == TMC_MODE_CIRCULAR_BUFFER)
+			__tmc_etb_enable(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: %d 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) {
+			WARN_ONCE(1, "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 tmc_show_trigger_cntr(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 scnprintf(buf, PAGE_SIZE, "%#lx\n", val);
+}
+
+static ssize_t tmc_store_trigger_cntr(struct device *dev,
+				      struct device_attribute *attr,
+				      const char *buf, size_t size)
+{
+	struct tmc_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, tmc_show_trigger_cntr,
+		   tmc_store_trigger_cntr);
+
+static struct attribute *tmc_attrs[] = {
+	&dev_attr_trigger_cntr.attr,
+	NULL,
+};
+
+static struct attribute_group tmc_attr_grp = {
+	.attrs = tmc_attrs,
+};
+
+static const struct attribute_group *tmc_etb_attr_grps[] = {
+	&tmc_attr_grp,
+	NULL,
+};
+
+static const struct attribute_group *tmc_etr_attr_grps[] = {
+	&tmc_attr_grp,
+	NULL,
+};
+
+static const struct attribute_group *tmc_etf_attr_grps[] = {
+	&tmc_attr_grp,
+	NULL,
+};
+
+static int __devinit tmc_probe(struct platform_device *pdev)
+{
+	int ret = 0;
+	uint32_t devid;
+	struct device *dev = &pdev->dev;
+	struct coresight_platform_data *pdata;
+	struct tmc_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;
+
+	ret = clk_prepare_enable(drvdata->clk);
+	if (ret)
+		return ret;
+
+	devid = tmc_readl(drvdata, CORESIGHT_DEVID);
+	drvdata->config_type = BMVAL(devid, 6, 7);
+
+	if (drvdata->config_type == TMC_CONFIG_TYPE_ETR) {
+		if (pdev->dev.of_node)
+			ret = of_property_read_u32(pdev->dev.of_node,
+				"arm,buffer-size", &drvdata->size);
+		if (ret)
+			drvdata->size = SZ_1M;
+	} else {
+		drvdata->size = tmc_readl(drvdata, TMC_RSZ) * BYTES_PER_WORD;
+	}
+
+	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 err0;
+	}
+	if (drvdata->config_type == TMC_CONFIG_TYPE_ETB) {
+		desc->type = CORESIGHT_DEV_TYPE_SINK;
+		desc->subtype.sink_subtype = CORESIGHT_DEV_SUBTYPE_SINK_BUFFER;
+		desc->ops = &tmc_etb_cs_ops;
+		desc->pdata = pdev->dev.platform_data;
+		desc->dev = &pdev->dev;
+		desc->groups = tmc_etb_attr_grps;
+		desc->owner = THIS_MODULE;
+		drvdata->csdev = coresight_register(desc);
+		if (IS_ERR(drvdata->csdev)) {
+			ret = PTR_ERR(drvdata->csdev);
+			goto err0;
+		}
+	} else if (drvdata->config_type == TMC_CONFIG_TYPE_ETR) {
+		desc->type = CORESIGHT_DEV_TYPE_SINK;
+		desc->subtype.sink_subtype = CORESIGHT_DEV_SUBTYPE_SINK_BUFFER;
+		desc->ops = &tmc_etr_cs_ops;
+		desc->pdata = pdev->dev.platform_data;
+		desc->dev = &pdev->dev;
+		desc->groups = tmc_etr_attr_grps;
+		desc->owner = THIS_MODULE;
+		drvdata->csdev = coresight_register(desc);
+		if (IS_ERR(drvdata->csdev)) {
+			ret = PTR_ERR(drvdata->csdev);
+			goto err0;
+		}
+	} else {
+		desc->type = CORESIGHT_DEV_TYPE_LINKSINK;
+		desc->subtype.sink_subtype = CORESIGHT_DEV_SUBTYPE_SINK_BUFFER;
+		desc->subtype.link_subtype = CORESIGHT_DEV_SUBTYPE_LINK_FIFO;
+		desc->ops = &tmc_etf_cs_ops;
+		desc->pdata = pdev->dev.platform_data;
+		desc->dev = &pdev->dev;
+		desc->groups = tmc_etf_attr_grps;
+		desc->owner = THIS_MODULE;
+		drvdata->csdev = coresight_register(desc);
+		if (IS_ERR(drvdata->csdev)) {
+			ret = PTR_ERR(drvdata->csdev);
+			goto err0;
+		}
+	}
+
+	drvdata->miscdev.name = ((struct coresight_platform_data *)
+				 (pdev->dev.platform_data))->name;
+	drvdata->miscdev.minor = MISC_DYNAMIC_MINOR;
+	drvdata->miscdev.fops = &tmc_fops;
+	ret = misc_register(&drvdata->miscdev);
+	if (ret)
+		goto err1;
+
+	dev_info(dev, "TMC initialized\n");
+	return 0;
+err1:
+	coresight_unregister(drvdata->csdev);
+err0:
+	dma_free_coherent(dev, drvdata->size, &drvdata->paddr, GFP_KERNEL);
+	return ret;
+}
+
+static int __devexit tmc_remove(struct platform_device *pdev)
+{
+	struct tmc_drvdata *drvdata = platform_get_drvdata(pdev);
+
+	misc_deregister(&drvdata->miscdev);
+	coresight_unregister(drvdata->csdev);
+	dma_free_coherent(drvdata->dev, drvdata->size, &drvdata->paddr,
+			  GFP_KERNEL);
+	return 0;
+}
+
+static struct of_device_id tmc_match[] = {
+	{.compatible = "arm,coresight-tmc"},
+	{}
+};
+
+static struct platform_driver tmc_driver = {
+	.probe          = tmc_probe,
+	.remove         = __devexit_p(tmc_remove),
+	.driver         = {
+		.name   = "coresight-tmc",
+		.owner	= THIS_MODULE,
+		.of_match_table = tmc_match,
+	},
+};
+
+static int __init tmc_init(void)
+{
+	return platform_driver_register(&tmc_driver);
+}
+module_init(tmc_init);
+
+static void __exit tmc_exit(void)
+{
+	platform_driver_unregister(&tmc_driver);
+}
+module_exit(tmc_exit);
+
+MODULE_LICENSE("GPL v2");
+MODULE_DESCRIPTION("CoreSight Trace Memory Controller driver");
-- 
Employee of Qualcomm Innovation Center, Inc.
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