[RFC 4/8] coresight: add CoreSight ETB driver

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

From: Pratik Patel <pratikp@codeaurora.org>

This driver manages CoreSight ETB (Embedded Trace Buffer) which
acts as a circular buffer sink collecting generated trace data.

Signed-off-by: Pratik Patel <pratikp@codeaurora.org>
---
 drivers/coresight/Makefile        |    2 +-
 drivers/coresight/coresight-etb.c |  467 +++++++++++++++++++++++++++++++++++++
 2 files changed, 468 insertions(+), 1 deletions(-)
 create mode 100644 drivers/coresight/coresight-etb.c

diff --git a/drivers/coresight/Makefile b/drivers/coresight/Makefile
index 540df99..3c1debc 100644
--- a/drivers/coresight/Makefile
+++ b/drivers/coresight/Makefile
@@ -3,4 +3,4 @@
 #
 obj-$(CONFIG_CORESIGHT) += coresight.o
 obj-$(CONFIG_OF) += of_coresight.o
-obj-$(CONFIG_CORESIGHT_LINKS_AND_SINKS) += coresight-tmc.o coresight-tpiu.o
+obj-$(CONFIG_CORESIGHT_LINKS_AND_SINKS) += coresight-tmc.o coresight-tpiu.o coresight-etb.o
diff --git a/drivers/coresight/coresight-etb.c b/drivers/coresight/coresight-etb.c
new file mode 100644
index 0000000..d52ab28
--- /dev/null
+++ b/drivers/coresight/coresight-etb.c
@@ -0,0 +1,467 @@
+/* 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");
-- 
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