arch/arm/mach-msm/rpm_log.c - kernel/msm - Gitiles

 /* Copyright (c) 2010-2011, 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/debugfs.h>
 #include <linux/delay.h>
 #include <linux/errno.h>
 #include <linux/init.h>
 #include <linux/io.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/platform_device.h>
 #include <linux/sched.h>
 #include <linux/slab.h>
 #include <linux/types.h>

 #include <asm/uaccess.h>

 #include <mach/msm_iomap.h>

 #include "rpm_log.h"

 /* registers in MSM_RPM_LOG_PAGE_INDICES */
 enum {
 	MSM_RPM_LOG_TAIL,
 	MSM_RPM_LOG_HEAD
 };

 /* used to 4 byte align message lengths */
 #define PADDED_LENGTH(x) (0xFFFFFFFC & ((x) + 3))

 /* calculates the character string length of a message of byte length x */
 #define PRINTED_LENGTH(x) ((x) * 6 + 3)

 /* number of ms to wait between checking for new messages in the RPM log */
 #define RECHECK_TIME (50)

 struct msm_rpm_log_buffer {
 	char *data;
 	u32 len;
 	u32 pos;
 	u32 max_len;
 	u32 read_idx;
 	struct msm_rpm_log_platform_data *pdata;
 };

 /******************************************************************************
  * Internal functions
  *****************************************************************************/

 static inline u32
 msm_rpm_log_read(const struct msm_rpm_log_platform_data *pdata, u32 page,
 		 u32 reg)
 {
 	return readl_relaxed(pdata->reg_base + pdata->reg_offsets[page]
 				+ reg * 4);
 }

 /*
  * msm_rpm_log_copy() - Copies messages from a volatile circular buffer in
  *			the RPM's shared memory into a private local buffer
  * msg_buffer:		pointer to local buffer (string)
  * buf_len:		length of local buffer in bytes
  * read_start_idx:	index into shared memory buffer
  *
  * Return value:	number of bytes written to the local buffer
  *
  * Copies messages stored in a circular buffer in the RPM Message Memory into
  * a specified local buffer.  The RPM processor is unaware of these reading
  * efforts, so care is taken to make sure that messages are valid both before
  * and after reading.  The RPM processor utilizes a ULog driver to write the
  * log.  The RPM processor maintains tail and head indices.  These correspond
  * to the next byte to write into, and the first valid byte, respectively.
  * Both indices increase monotonically (except for rollover).
  *
  * Messages take the form of [(u32)length] [(char)data0,1,...] in which the
  * length specifies the number of payload bytes.  Messages must be 4 byte
  * aligned, so padding is added at the end of a message as needed.
  *
  * Print format:
  * - 0xXX, 0xXX, 0xXX
  * - 0xXX
  * etc...
  */
 static u32 msm_rpm_log_copy(const struct msm_rpm_log_platform_data *pdata,
 			    char *msg_buffer, u32 buf_len, u32 *read_idx)
 {
 	u32 head_idx, tail_idx;
 	u32 pos = 0;
 	u32 i = 0;
 	u32 msg_len;
 	u32 pos_start;
 	char temp[4];

 	tail_idx = msm_rpm_log_read(pdata, MSM_RPM_LOG_PAGE_INDICES,
 				    MSM_RPM_LOG_TAIL);
 	head_idx = msm_rpm_log_read(pdata, MSM_RPM_LOG_PAGE_INDICES,
 				    MSM_RPM_LOG_HEAD);

 	/* loop while the remote buffer has valid messages left to read */
 	while (tail_idx - head_idx > 0 && tail_idx - *read_idx > 0) {
 		head_idx = msm_rpm_log_read(pdata, MSM_RPM_LOG_PAGE_INDICES,
 					    MSM_RPM_LOG_HEAD);
 		/* check if the message to be read is valid */
 		if (tail_idx - *read_idx > tail_idx - head_idx) {
 			*read_idx = head_idx;
 			continue;
 		}
 		/*
 		 * Ensure that all indices are 4 byte aligned.
 		 * This conditions is required to interact with a ULog buffer
 		 * properly.
 		 */
 		if (!IS_ALIGNED((tail_idx | head_idx | *read_idx), 4))
 			break;

 		msg_len = msm_rpm_log_read(pdata, MSM_RPM_LOG_PAGE_BUFFER,
 					(*read_idx >> 2) & pdata->log_len_mask);

 		/* handle messages that claim to be longer than the log */
 		if (PADDED_LENGTH(msg_len) > tail_idx - *read_idx - 4)
 			msg_len = tail_idx - *read_idx - 4;

 		/* check that the local buffer has enough space for this msg */
 		if (pos + PRINTED_LENGTH(msg_len) > buf_len)
 			break;

 		pos_start = pos;
 		pos += scnprintf(msg_buffer + pos, buf_len - pos, "- ");

 		/* copy message payload to local buffer */
 		for (i = 0; i < msg_len; i++) {
 			/* read from shared memory 4 bytes at a time */
 			if (IS_ALIGNED(i, 4))
 				*((u32 *)temp) = msm_rpm_log_read(pdata,
 						MSM_RPM_LOG_PAGE_BUFFER,
 						((*read_idx + 4 + i) >> 2) &
 							pdata->log_len_mask);

 			pos += scnprintf(msg_buffer + pos, buf_len - pos,
 					 "0x%02X, ", temp[i & 0x03]);
 		}

 		pos += scnprintf(msg_buffer + pos, buf_len - pos, "\n");

 		head_idx = msm_rpm_log_read(pdata, MSM_RPM_LOG_PAGE_INDICES,
 					    MSM_RPM_LOG_HEAD);

 		/* roll back if message that was read is not still valid */
 		if (tail_idx - *read_idx > tail_idx - head_idx)
 			pos = pos_start;

 		*read_idx += PADDED_LENGTH(msg_len) + 4;
 	}

 	return pos;
 }


 /*
  * msm_rpm_log_file_read() - Reads in log buffer messages then outputs them to a
  *			     user buffer
  *
  * Return value:
  *	0:	 success
  *	-ENOMEM: no memory available
  *	-EINVAL: user buffer null or requested bytes 0
  *	-EFAULT: user buffer not writeable
  *	-EAGAIN: no bytes available at the moment
  */
 static ssize_t msm_rpm_log_file_read(struct file *file, char __user *bufu,
 				     size_t count, loff_t *ppos)
 {
 	u32 out_len, remaining;
 	struct msm_rpm_log_platform_data *pdata;
 	struct msm_rpm_log_buffer *buf;

 	buf = file->private_data;
 	pdata = buf->pdata;
 	if (!pdata)
 		return -EINVAL;
 	if (!buf)
 		return -ENOMEM;
 	if (!buf->data)
 		return -ENOMEM;
 	if (!bufu || count < 0)
 		return -EINVAL;
 	if (!access_ok(VERIFY_WRITE, bufu, count))
 		return -EFAULT;

 	/* check for more messages if local buffer empty */
 	if (buf->pos == buf->len) {
 		buf->pos = 0;
 		buf->len = msm_rpm_log_copy(pdata, buf->data, buf->max_len,
 						&(buf->read_idx));
 	}

 	if ((file->f_flags & O_NONBLOCK) && buf->len == 0)
 		return -EAGAIN;

 	/* loop until new messages arrive */
 	while (buf->len == 0) {
 		cond_resched();
 		if (msleep_interruptible(RECHECK_TIME))
 			break;
 		buf->len = msm_rpm_log_copy(pdata, buf->data, buf->max_len,
 						&(buf->read_idx));
 	}

 	out_len = ((buf->len - buf->pos) < count ? buf->len - buf->pos : count);

 	remaining = __copy_to_user(bufu, &(buf->data[buf->pos]), out_len);
 	buf->pos += out_len - remaining;

 	return out_len - remaining;
 }


 /*
  * msm_rpm_log_file_open() - Allows a new reader to open the RPM log virtual
  *                           file
  *
  * One local buffer is kmalloc'ed for each reader, so no resource sharing has
  * to take place (besides the read only access to the RPM log buffer).
  *
  * Return value:
  *	0:	 success
  *	-ENOMEM: no memory available
  */
 static int msm_rpm_log_file_open(struct inode *inode, struct file *file)
 {
 	struct msm_rpm_log_buffer *buf;
 	struct msm_rpm_log_platform_data *pdata;

 	pdata = inode->i_private;
 	if (!pdata)
 		return -EINVAL;

 	file->private_data =
 		   kmalloc(sizeof(struct msm_rpm_log_buffer), GFP_KERNEL);
 	if (!file->private_data) {
 		pr_err("%s: ERROR kmalloc failed to allocate %d bytes\n",
 			__func__, sizeof(struct msm_rpm_log_buffer));
 		return -ENOMEM;
 	}
 	buf = file->private_data;

 	buf->data = kmalloc(PRINTED_LENGTH(pdata->log_len), GFP_KERNEL);
 	if (!buf->data) {
 		kfree(file->private_data);
 		file->private_data = NULL;
 		pr_err("%s: ERROR kmalloc failed to allocate %d bytes\n",
 			__func__, PRINTED_LENGTH(pdata->log_len));
 		return -ENOMEM;
 	}

 	buf->pdata = pdata;
 	buf->len = 0;
 	buf->pos = 0;
 	buf->max_len = PRINTED_LENGTH(pdata->log_len);
 	buf->read_idx = msm_rpm_log_read(pdata, MSM_RPM_LOG_PAGE_INDICES,
 					 MSM_RPM_LOG_HEAD);
 	return 0;
 }

 static int msm_rpm_log_file_close(struct inode *inode, struct file *file)
 {
 	kfree(((struct msm_rpm_log_buffer *)file->private_data)->data);
 	kfree(file->private_data);
 	return 0;
 }


 static const struct file_operations msm_rpm_log_file_fops = {
 	.owner   = THIS_MODULE,
 	.open    = msm_rpm_log_file_open,
 	.read    = msm_rpm_log_file_read,
 	.release = msm_rpm_log_file_close,
 };

 static int __devinit msm_rpm_log_probe(struct platform_device *pdev)
 {
 	struct dentry *dent;
 	struct msm_rpm_log_platform_data *pdata;

 	pdata = pdev->dev.platform_data;
 	if (!pdata)
 		return -EINVAL;

 	pdata->reg_base = ioremap(pdata->phys_addr_base, pdata->phys_size);
 	if (!pdata->reg_base) {
 		pr_err("%s: ERROR could not ioremap: start=%p, len=%u\n",
 			__func__, (void *) pdata->phys_addr_base,
 			pdata->phys_size);
 		return -EBUSY;
 	}

 	dent = debugfs_create_file("rpm_log", S_IRUGO, NULL,
 			pdev->dev.platform_data, &msm_rpm_log_file_fops);
 	if (!dent) {
 		pr_err("%s: ERROR debugfs_create_file failed\n", __func__);
 		return -ENOMEM;
 	}

 	platform_set_drvdata(pdev, dent);

 	pr_notice("%s: OK\n", __func__);
 	return 0;
 }

 static int __devexit msm_rpm_log_remove(struct platform_device *pdev)
 {
 	struct dentry *dent;
 	struct msm_rpm_log_platform_data *pdata;

 	pdata = pdev->dev.platform_data;

 	iounmap(pdata->reg_base);

 	dent = platform_get_drvdata(pdev);
 	debugfs_remove(dent);
 	platform_set_drvdata(pdev, NULL);

 	pr_notice("%s: OK\n", __func__);
 	return 0;
 }

 static struct platform_driver msm_rpm_log_driver = {
 	.probe		= msm_rpm_log_probe,
 	.remove		= __devexit_p(msm_rpm_log_remove),
 	.driver		= {
 		.name = "msm_rpm_log",
 		.owner = THIS_MODULE,
 	},
 };

 static int __init msm_rpm_log_init(void)
 {
 	return platform_driver_register(&msm_rpm_log_driver);
 }

 static void __exit msm_rpm_log_exit(void)
 {
 	platform_driver_unregister(&msm_rpm_log_driver);
 }

 module_init(msm_rpm_log_init);
 module_exit(msm_rpm_log_exit);

 MODULE_LICENSE("GPL v2");
 MODULE_DESCRIPTION("MSM RPM Log driver");
 MODULE_VERSION("1.0");
 MODULE_ALIAS("platform:msm_rpm_log");
	/* Copyright (c) 2010-2011, 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/debugfs.h>
	#include <linux/delay.h>
	#include <linux/errno.h>
	#include <linux/init.h>
	#include <linux/io.h>
	#include <linux/kernel.h>
	#include <linux/module.h>
	#include <linux/platform_device.h>
	#include <linux/sched.h>
	#include <linux/slab.h>
	#include <linux/types.h>

	#include <asm/uaccess.h>

	#include <mach/msm_iomap.h>

	#include "rpm_log.h"

	/* registers in MSM_RPM_LOG_PAGE_INDICES */
	enum {
	MSM_RPM_LOG_TAIL,
	MSM_RPM_LOG_HEAD
	};

	/* used to 4 byte align message lengths */
	#define PADDED_LENGTH(x) (0xFFFFFFFC & ((x) + 3))

	/* calculates the character string length of a message of byte length x */
	#define PRINTED_LENGTH(x) ((x) * 6 + 3)

	/* number of ms to wait between checking for new messages in the RPM log */
	#define RECHECK_TIME (50)

	struct msm_rpm_log_buffer {
	char *data;
	u32 len;
	u32 pos;
	u32 max_len;
	u32 read_idx;
	struct msm_rpm_log_platform_data *pdata;
	};

	/******************************************************************************
	* Internal functions
	*****************************************************************************/

	static inline u32
	msm_rpm_log_read(const struct msm_rpm_log_platform_data *pdata, u32 page,
	u32 reg)
	{
	return readl_relaxed(pdata->reg_base + pdata->reg_offsets[page]
	+ reg * 4);
	}

	/*
	* msm_rpm_log_copy() - Copies messages from a volatile circular buffer in
	* the RPM's shared memory into a private local buffer
	* msg_buffer: pointer to local buffer (string)
	* buf_len: length of local buffer in bytes
	* read_start_idx: index into shared memory buffer
	*
	* Return value: number of bytes written to the local buffer
	*
	* Copies messages stored in a circular buffer in the RPM Message Memory into
	* a specified local buffer. The RPM processor is unaware of these reading
	* efforts, so care is taken to make sure that messages are valid both before
	* and after reading. The RPM processor utilizes a ULog driver to write the
	* log. The RPM processor maintains tail and head indices. These correspond
	* to the next byte to write into, and the first valid byte, respectively.
	* Both indices increase monotonically (except for rollover).
	*
	* Messages take the form of [(u32)length] [(char)data0,1,...] in which the
	* length specifies the number of payload bytes. Messages must be 4 byte
	* aligned, so padding is added at the end of a message as needed.
	*
	* Print format:
	* - 0xXX, 0xXX, 0xXX
	* - 0xXX
	* etc...
	*/
	static u32 msm_rpm_log_copy(const struct msm_rpm_log_platform_data *pdata,
	char msg_buffer, u32 buf_len, u32 read_idx)
	{
	u32 head_idx, tail_idx;
	u32 pos = 0;
	u32 i = 0;
	u32 msg_len;
	u32 pos_start;
	char temp[4];

	tail_idx = msm_rpm_log_read(pdata, MSM_RPM_LOG_PAGE_INDICES,
	MSM_RPM_LOG_TAIL);
	head_idx = msm_rpm_log_read(pdata, MSM_RPM_LOG_PAGE_INDICES,
	MSM_RPM_LOG_HEAD);

	/* loop while the remote buffer has valid messages left to read */
	while (tail_idx - head_idx > 0 && tail_idx - *read_idx > 0) {
	head_idx = msm_rpm_log_read(pdata, MSM_RPM_LOG_PAGE_INDICES,
	MSM_RPM_LOG_HEAD);
	/* check if the message to be read is valid */
	if (tail_idx - *read_idx > tail_idx - head_idx) {
	*read_idx = head_idx;
	continue;
	}
	/*
	* Ensure that all indices are 4 byte aligned.
	* This conditions is required to interact with a ULog buffer
	* properly.
	*/
	if (!IS_ALIGNED((tail_idx \| head_idx \| *read_idx), 4))
	break;

	msg_len = msm_rpm_log_read(pdata, MSM_RPM_LOG_PAGE_BUFFER,
	(*read_idx >> 2) & pdata->log_len_mask);

	/* handle messages that claim to be longer than the log */
	if (PADDED_LENGTH(msg_len) > tail_idx - *read_idx - 4)
	msg_len = tail_idx - *read_idx - 4;

	/* check that the local buffer has enough space for this msg */
	if (pos + PRINTED_LENGTH(msg_len) > buf_len)
	break;

	pos_start = pos;
	pos += scnprintf(msg_buffer + pos, buf_len - pos, "- ");

	/* copy message payload to local buffer */
	for (i = 0; i < msg_len; i++) {
	/* read from shared memory 4 bytes at a time */
	if (IS_ALIGNED(i, 4))
	((u32 )temp) = msm_rpm_log_read(pdata,
	MSM_RPM_LOG_PAGE_BUFFER,
	((*read_idx + 4 + i) >> 2) &
	pdata->log_len_mask);

	pos += scnprintf(msg_buffer + pos, buf_len - pos,
	"0x%02X, ", temp[i & 0x03]);
	}

	pos += scnprintf(msg_buffer + pos, buf_len - pos, "\n");

	head_idx = msm_rpm_log_read(pdata, MSM_RPM_LOG_PAGE_INDICES,
	MSM_RPM_LOG_HEAD);

	/* roll back if message that was read is not still valid */
	if (tail_idx - *read_idx > tail_idx - head_idx)
	pos = pos_start;

	*read_idx += PADDED_LENGTH(msg_len) + 4;
	}

	return pos;
	}


	/*
	* msm_rpm_log_file_read() - Reads in log buffer messages then outputs them to a
	* user buffer
	*
	* Return value:
	* 0: success
	* -ENOMEM: no memory available
	* -EINVAL: user buffer null or requested bytes 0
	* -EFAULT: user buffer not writeable
	* -EAGAIN: no bytes available at the moment
	*/
	static ssize_t msm_rpm_log_file_read(struct file file, char __user bufu,
	size_t count, loff_t *ppos)
	{
	u32 out_len, remaining;
	struct msm_rpm_log_platform_data *pdata;
	struct msm_rpm_log_buffer *buf;

	buf = file->private_data;
	pdata = buf->pdata;
	if (!pdata)
	return -EINVAL;
	if (!buf)
	return -ENOMEM;
	if (!buf->data)
	return -ENOMEM;
	if (!bufu \|\| count < 0)
	return -EINVAL;
	if (!access_ok(VERIFY_WRITE, bufu, count))
	return -EFAULT;

	/* check for more messages if local buffer empty */
	if (buf->pos == buf->len) {
	buf->pos = 0;
	buf->len = msm_rpm_log_copy(pdata, buf->data, buf->max_len,
	&(buf->read_idx));
	}

	if ((file->f_flags & O_NONBLOCK) && buf->len == 0)
	return -EAGAIN;

	/* loop until new messages arrive */
	while (buf->len == 0) {
	cond_resched();
	if (msleep_interruptible(RECHECK_TIME))
	break;
	buf->len = msm_rpm_log_copy(pdata, buf->data, buf->max_len,
	&(buf->read_idx));
	}

	out_len = ((buf->len - buf->pos) < count ? buf->len - buf->pos : count);

	remaining = __copy_to_user(bufu, &(buf->data[buf->pos]), out_len);
	buf->pos += out_len - remaining;

	return out_len - remaining;
	}


	/*
	* msm_rpm_log_file_open() - Allows a new reader to open the RPM log virtual
	* file
	*
	* One local buffer is kmalloc'ed for each reader, so no resource sharing has
	* to take place (besides the read only access to the RPM log buffer).
	*
	* Return value:
	* 0: success
	* -ENOMEM: no memory available
	*/
	static int msm_rpm_log_file_open(struct inode inode, struct file file)
	{
	struct msm_rpm_log_buffer *buf;
	struct msm_rpm_log_platform_data *pdata;

	pdata = inode->i_private;
	if (!pdata)
	return -EINVAL;

	file->private_data =
	kmalloc(sizeof(struct msm_rpm_log_buffer), GFP_KERNEL);
	if (!file->private_data) {
	pr_err("%s: ERROR kmalloc failed to allocate %d bytes\n",
	__func__, sizeof(struct msm_rpm_log_buffer));
	return -ENOMEM;
	}
	buf = file->private_data;

	buf->data = kmalloc(PRINTED_LENGTH(pdata->log_len), GFP_KERNEL);
	if (!buf->data) {
	kfree(file->private_data);
	file->private_data = NULL;
	pr_err("%s: ERROR kmalloc failed to allocate %d bytes\n",
	__func__, PRINTED_LENGTH(pdata->log_len));
	return -ENOMEM;
	}

	buf->pdata = pdata;
	buf->len = 0;
	buf->pos = 0;
	buf->max_len = PRINTED_LENGTH(pdata->log_len);
	buf->read_idx = msm_rpm_log_read(pdata, MSM_RPM_LOG_PAGE_INDICES,
	MSM_RPM_LOG_HEAD);
	return 0;
	}

	static int msm_rpm_log_file_close(struct inode inode, struct file file)
	{
	kfree(((struct msm_rpm_log_buffer *)file->private_data)->data);
	kfree(file->private_data);
	return 0;
	}


	static const struct file_operations msm_rpm_log_file_fops = {
	.owner = THIS_MODULE,
	.open = msm_rpm_log_file_open,
	.read = msm_rpm_log_file_read,
	.release = msm_rpm_log_file_close,
	};

	static int __devinit msm_rpm_log_probe(struct platform_device *pdev)
	{
	struct dentry *dent;
	struct msm_rpm_log_platform_data *pdata;

	pdata = pdev->dev.platform_data;
	if (!pdata)
	return -EINVAL;

	pdata->reg_base = ioremap(pdata->phys_addr_base, pdata->phys_size);
	if (!pdata->reg_base) {
	pr_err("%s: ERROR could not ioremap: start=%p, len=%u\n",
	__func__, (void *) pdata->phys_addr_base,
	pdata->phys_size);
	return -EBUSY;
	}

	dent = debugfs_create_file("rpm_log", S_IRUGO, NULL,
	pdev->dev.platform_data, &msm_rpm_log_file_fops);
	if (!dent) {
	pr_err("%s: ERROR debugfs_create_file failed\n", __func__);
	return -ENOMEM;
	}

	platform_set_drvdata(pdev, dent);

	pr_notice("%s: OK\n", __func__);
	return 0;
	}

	static int __devexit msm_rpm_log_remove(struct platform_device *pdev)
	{
	struct dentry *dent;
	struct msm_rpm_log_platform_data *pdata;

	pdata = pdev->dev.platform_data;

	iounmap(pdata->reg_base);

	dent = platform_get_drvdata(pdev);
	debugfs_remove(dent);
	platform_set_drvdata(pdev, NULL);

	pr_notice("%s: OK\n", __func__);
	return 0;
	}

	static struct platform_driver msm_rpm_log_driver = {
	.probe = msm_rpm_log_probe,
	.remove = __devexit_p(msm_rpm_log_remove),
	.driver = {
	.name = "msm_rpm_log",
	.owner = THIS_MODULE,
	},
	};

	static int __init msm_rpm_log_init(void)
	{
	return platform_driver_register(&msm_rpm_log_driver);
	}

	static void __exit msm_rpm_log_exit(void)
	{
	platform_driver_unregister(&msm_rpm_log_driver);
	}

	module_init(msm_rpm_log_init);
	module_exit(msm_rpm_log_exit);

	MODULE_LICENSE("GPL v2");
	MODULE_DESCRIPTION("MSM RPM Log driver");
	MODULE_VERSION("1.0");
	MODULE_ALIAS("platform:msm_rpm_log");