arch/arm/mach-msm/qdss-etb.c

/* Copyright (c) 2011, Code Aurora Forum. 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/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 "qdss.h"

#define etb_writel(etb, val, off)	__raw_writel((val), etb.base + off)
#define etb_readl(etb, off)		__raw_readl(etb.base + off)

#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 ETB_LOCK()							\
do {									\
	mb();								\
	etb_writel(etb, MAGIC2, CS_LAR);				\
} while (0)
#define ETB_UNLOCK()							\
do {									\
	etb_writel(etb, MAGIC1, CS_LAR);				\
	mb();								\
} while (0)

struct etb_ctx {
	uint8_t		*buf;
	void __iomem	*base;
	bool		enabled;
	bool		reading;
	struct mutex	lock;
	atomic_t	in_use;
	struct device	*dev;
};

static struct etb_ctx etb;

static void __etb_enable(void)
{
	int i;

	ETB_UNLOCK();

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

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

	etb_writel(etb, BIT(13) | BIT(0), ETB_FFCR);
	etb_writel(etb, BIT(0), ETB_CTL_REG);

	ETB_LOCK();
}

void etb_enable(void)
{
	mutex_lock(&etb.lock);
	__etb_enable();
	etb.enabled = true;
	dev_info(etb.dev, "etb enabled\n");
	mutex_unlock(&etb.lock);
}

static void __etb_disable(void)
{
	int count;

	ETB_UNLOCK();

	etb_writel(etb, BIT(12) | BIT(13), ETB_FFCR);
	etb_writel(etb, 0x0, ETB_CTL_REG);

	for (count = TIMEOUT_US; BVAL(etb_readl(etb, ETB_FFSR), 1) != 1
				&& count > 0; count--)
		udelay(1);
	WARN(count == 0, "timeout while disabling etb\n");

	ETB_LOCK();
}

void etb_disable(void)
{
	mutex_lock(&etb.lock);
	__etb_disable();
	etb.enabled = false;
	dev_info(etb.dev, "etb disabled\n");
	mutex_unlock(&etb.lock);
}

static void __etb_dump(void)
{
	int i;
	uint8_t *buf_ptr;
	uint32_t read_data;
	uint32_t read_ptr;
	uint32_t write_ptr;

	ETB_UNLOCK();

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

	if ((etb_readl(etb, ETB_STATUS_REG) & BIT(0)) == 0)
		etb_writel(etb, 0x0, ETB_RAM_READ_POINTER);
	else
		etb_writel(etb, write_ptr, ETB_RAM_READ_POINTER);

	buf_ptr = etb.buf;
	for (i = 0; i < ETB_SIZE_WORDS; i++) {
		read_data = etb_readl(etb, ETB_RAM_READ_DATA_REG);
		*buf_ptr = read_data >> 0;
		buf_ptr++;
		*buf_ptr = read_data >> 8;
		buf_ptr++;
		*buf_ptr = read_data >> 16;
		buf_ptr++;
		*buf_ptr = read_data >> 24;
		buf_ptr++;
	}

	etb_writel(etb, read_ptr, ETB_RAM_READ_POINTER);

	ETB_LOCK();
}

void etb_dump(void)
{
	mutex_lock(&etb.lock);
	if (etb.enabled) {
		__etb_disable();
		__etb_dump();
		__etb_enable();

		dev_info(etb.dev, "etb dumped\n");
	}
	mutex_unlock(&etb.lock);
}

static int etb_open(struct inode *inode, struct file *file)
{
	if (atomic_cmpxchg(&etb.in_use, 0, 1))
		return -EBUSY;

	dev_dbg(etb.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)
{
	if (etb.reading == false) {
		etb_dump();
		etb.reading = true;
	}

	if (*ppos + len > ETB_SIZE_WORDS * BYTES_PER_WORD)
		len = ETB_SIZE_WORDS * BYTES_PER_WORD - *ppos;

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

	*ppos += len;

	dev_dbg(etb.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)
{
	etb.reading = false;

	atomic_set(&etb.in_use, 0);

	dev_dbg(etb.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,
};

static struct miscdevice etb_misc = {
	.name =		"msm_etb",
	.minor =	MISC_DYNAMIC_MINOR,
	.fops =		&etb_fops,
};

static int __devinit etb_probe(struct platform_device *pdev)
{
	int ret;
	struct resource *res;

	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	if (!res) {
		ret = -EINVAL;
		goto err_res;
	}

	etb.base = ioremap_nocache(res->start, resource_size(res));
	if (!etb.base) {
		ret = -EINVAL;
		goto err_ioremap;
	}

	etb.dev = &pdev->dev;

	ret = misc_register(&etb_misc);
	if (ret)
		goto err_misc;

	etb.buf = kzalloc(ETB_SIZE_WORDS * BYTES_PER_WORD, GFP_KERNEL);
	if (!etb.buf) {
		ret = -ENOMEM;
		goto err_alloc;
	}

	mutex_init(&etb.lock);

	return 0;

err_alloc:
	misc_deregister(&etb_misc);
err_misc:
	iounmap(etb.base);
err_ioremap:
err_res:
	return ret;
}

static int __devexit etb_remove(struct platform_device *pdev)
{
	if (etb.enabled)
		etb_disable();
	mutex_destroy(&etb.lock);
	kfree(etb.buf);
	misc_deregister(&etb_misc);
	iounmap(etb.base);

	return 0;
}

static struct platform_driver etb_driver = {
	.probe          = etb_probe,
	.remove         = __devexit_p(etb_remove),
	.driver         = {
		.name   = "msm_etb",
	},
};

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");