industrialio-ring.c
/* The industrial I/O core
*
* Copyright (c) 2008 Jonathan Cameron
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 as published by
* the Free Software Foundation.
*
* Handling of ring allocation / resizing.
*
*
* Things to look at here.
* - Better memory allocation techniques?
* - Alternative access techniques?
*/
#include <linux/kernel.h>
#include <linux/device.h>
#include <linux/fs.h>
#include <linux/poll.h>
#include <linux/cdev.h>
#include <linux/slab.h>
#include "iio.h"
#include "ring_generic.h"
int iio_push_ring_event(struct iio_ring_buffer *ring_buf,
int event_code,
s64 timestamp)
{
return __iio_push_event(&ring_buf->ev_int,
event_code,
timestamp,
&ring_buf->shared_ev_pointer);
}
EXPORT_SYMBOL(iio_push_ring_event);
int iio_push_or_escallate_ring_event(struct iio_ring_buffer *ring_buf,
int event_code,
s64 timestamp)
{
if (ring_buf->shared_ev_pointer.ev_p)
__iio_change_event(ring_buf->shared_ev_pointer.ev_p,
event_code,
timestamp);
else
return iio_push_ring_event(ring_buf,
event_code,
timestamp);
return 0;
}
EXPORT_SYMBOL(iio_push_or_escallate_ring_event);
/**
* iio_ring_open() - chrdev file open for ring buffer access
*
* This function relies on all ring buffer implementations having an
* iio_ring_buffer as their first element.
**/
static int iio_ring_open(struct inode *inode, struct file *filp)
{
struct iio_handler *hand
= container_of(inode->i_cdev, struct iio_handler, chrdev);
struct iio_ring_buffer *rb = hand->private;
filp->private_data = hand->private;
if (rb->access.mark_in_use)
rb->access.mark_in_use(rb);
return 0;
}
/**
* iio_ring_release() - chrdev file close ring buffer access
*
* This function relies on all ring buffer implementations having an
* iio_ring_buffer as their first element.
**/
static int iio_ring_release(struct inode *inode, struct file *filp)
{
struct cdev *cd = inode->i_cdev;
struct iio_handler *hand = iio_cdev_to_handler(cd);
struct iio_ring_buffer *rb = hand->private;
clear_bit(IIO_BUSY_BIT_POS, &rb->access_handler.flags);
if (rb->access.unmark_in_use)
rb->access.unmark_in_use(rb);
return 0;
}
/**
* iio_ring_rip_outer() - chrdev read for ring buffer access
*
* This function relies on all ring buffer implementations having an
* iio_ring _bufer as their first element.
**/
static ssize_t iio_ring_rip_outer(struct file *filp, char __user *buf,
size_t count, loff_t *f_ps)
{
struct iio_ring_buffer *rb = filp->private_data;
int ret, dead_offset, copied;
u8 *data;
/* rip lots must exist. */
if (!rb->access.rip_lots)
return -EINVAL;
copied = rb->access.rip_lots(rb, count, &data, &dead_offset);
if (copied <= 0) {
ret = copied;
goto error_ret;
}
if (copy_to_user(buf, data + dead_offset, copied)) {
ret = -EFAULT;
goto error_free_data_cpy;
}
/* In clever ring buffer designs this may not need to be freed.
* When such a design exists I'll add this to ring access funcs.
*/
kfree(data);
return copied;
error_free_data_cpy:
kfree(data);
error_ret:
return ret;
}
static const struct file_operations iio_ring_fileops = {
.read = iio_ring_rip_outer,
.release = iio_ring_release,
.open = iio_ring_open,
.owner = THIS_MODULE,
.llseek = noop_llseek,
};
/**
* __iio_request_ring_buffer_event_chrdev() - allocate ring event chrdev
* @buf: ring buffer whose event chrdev we are allocating
* @id: id of this ring buffer (typically 0)
* @owner: the module who owns the ring buffer (for ref counting)
* @dev: device with which the chrdev is associated
**/
static inline int
__iio_request_ring_buffer_event_chrdev(struct iio_ring_buffer *buf,
int id,
struct module *owner,
struct device *dev)
{
int ret;
snprintf(buf->ev_int._name, sizeof(buf->ev_int._name),
"%s:event%d",
dev_name(&buf->dev),
id);
ret = iio_setup_ev_int(&(buf->ev_int),
buf->ev_int._name,
owner,
dev);
if (ret)
goto error_ret;
return 0;
error_ret:
return ret;
}
static inline void
__iio_free_ring_buffer_event_chrdev(struct iio_ring_buffer *buf)
{
iio_free_ev_int(&(buf->ev_int));
}
static void iio_ring_access_release(struct device *dev)
{
struct iio_ring_buffer *buf
= access_dev_to_iio_ring_buffer(dev);
cdev_del(&buf->access_handler.chrdev);
iio_device_free_chrdev_minor(MINOR(dev->devt));
}
static struct device_type iio_ring_access_type = {
.release = iio_ring_access_release,
};
static inline int
__iio_request_ring_buffer_access_chrdev(struct iio_ring_buffer *buf,
int id,
struct module *owner)
{
int ret, minor;
buf->access_handler.flags = 0;
buf->access_dev.parent = &buf->dev;
buf->access_dev.bus = &iio_bus_type;
buf->access_dev.type = &iio_ring_access_type;
device_initialize(&buf->access_dev);
minor = iio_device_get_chrdev_minor();
if (minor < 0) {
ret = minor;
goto error_device_put;
}
buf->access_dev.devt = MKDEV(MAJOR(iio_devt), minor);
buf->access_id = id;
dev_set_name(&buf->access_dev, "%s:access%d",
dev_name(&buf->dev),
buf->access_id);
ret = device_add(&buf->access_dev);
if (ret < 0) {
printk(KERN_ERR "failed to add the ring access dev\n");
goto error_device_put;
}
cdev_init(&buf->access_handler.chrdev, &iio_ring_fileops);
buf->access_handler.chrdev.owner = owner;
ret = cdev_add(&buf->access_handler.chrdev, buf->access_dev.devt, 1);
if (ret) {
printk(KERN_ERR "failed to allocate ring access chrdev\n");
goto error_device_unregister;
}
return 0;
error_device_unregister:
device_unregister(&buf->access_dev);
error_device_put:
put_device(&buf->access_dev);
return ret;
}
static void __iio_free_ring_buffer_access_chrdev(struct iio_ring_buffer *buf)
{
device_unregister(&buf->access_dev);
}
void iio_ring_buffer_init(struct iio_ring_buffer *ring,
struct iio_dev *dev_info)
{
if (ring->access.mark_param_change)
ring->access.mark_param_change(ring);
ring->indio_dev = dev_info;
ring->ev_int.private = ring;
ring->access_handler.private = ring;
ring->shared_ev_pointer.ev_p = NULL;
spin_lock_init(&ring->shared_ev_pointer.lock);
}
EXPORT_SYMBOL(iio_ring_buffer_init);
int iio_ring_buffer_register(struct iio_ring_buffer *ring, int id)
{
int ret;
ring->id = id;
dev_set_name(&ring->dev, "%s:buffer%d",
dev_name(ring->dev.parent),
ring->id);
ret = device_add(&ring->dev);
if (ret)
goto error_ret;
ret = __iio_request_ring_buffer_event_chrdev(ring,
0,
ring->owner,
&ring->dev);
if (ret)
goto error_remove_device;
ret = __iio_request_ring_buffer_access_chrdev(ring,
0,
ring->owner);
if (ret)
goto error_free_ring_buffer_event_chrdev;
if (ring->scan_el_attrs) {
ret = sysfs_create_group(&ring->dev.kobj,
ring->scan_el_attrs);
if (ret) {
dev_err(&ring->dev,
"Failed to add sysfs scan elements\n");
goto error_free_ring_buffer_event_chrdev;
}
}
return ret;
error_free_ring_buffer_event_chrdev:
__iio_free_ring_buffer_event_chrdev(ring);
error_remove_device:
device_del(&ring->dev);
error_ret:
return ret;
}
EXPORT_SYMBOL(iio_ring_buffer_register);
void iio_ring_buffer_unregister(struct iio_ring_buffer *ring)
{
if (ring->scan_el_attrs)
sysfs_remove_group(&ring->dev.kobj,
ring->scan_el_attrs);
__iio_free_ring_buffer_access_chrdev(ring);
__iio_free_ring_buffer_event_chrdev(ring);
device_del(&ring->dev);
}
EXPORT_SYMBOL(iio_ring_buffer_unregister);
ssize_t iio_read_ring_length(struct device *dev,
struct device_attribute *attr,
char *buf)
{
int len = 0;
struct iio_ring_buffer *ring = dev_get_drvdata(dev);
if (ring->access.get_length)
len = sprintf(buf, "%d\n",
ring->access.get_length(ring));
return len;
}
EXPORT_SYMBOL(iio_read_ring_length);
ssize_t iio_write_ring_length(struct device *dev,
struct device_attribute *attr,
const char *buf,
size_t len)
{
int ret;
ulong val;
struct iio_ring_buffer *ring = dev_get_drvdata(dev);
ret = strict_strtoul(buf, 10, &val);
if (ret)
return ret;
if (ring->access.get_length)
if (val == ring->access.get_length(ring))
return len;
if (ring->access.set_length) {
ring->access.set_length(ring, val);
if (ring->access.mark_param_change)
ring->access.mark_param_change(ring);
}
return len;
}
EXPORT_SYMBOL(iio_write_ring_length);
ssize_t iio_read_ring_bytes_per_datum(struct device *dev,
struct device_attribute *attr,
char *buf)
{
int len = 0;
struct iio_ring_buffer *ring = dev_get_drvdata(dev);
if (ring->access.get_bytes_per_datum)
len = sprintf(buf, "%d\n",
ring->access.get_bytes_per_datum(ring));
return len;
}
EXPORT_SYMBOL(iio_read_ring_bytes_per_datum);
ssize_t iio_store_ring_enable(struct device *dev,
struct device_attribute *attr,
const char *buf,
size_t len)
{
int ret;
bool requested_state, current_state;
int previous_mode;
struct iio_ring_buffer *ring = dev_get_drvdata(dev);
struct iio_dev *dev_info = ring->indio_dev;
mutex_lock(&dev_info->mlock);
previous_mode = dev_info->currentmode;
requested_state = !(buf[0] == '0');
current_state = !!(previous_mode & INDIO_ALL_RING_MODES);
if (current_state == requested_state) {
printk(KERN_INFO "iio-ring, current state requested again\n");
goto done;
}
if (requested_state) {
if (ring->preenable) {
ret = ring->preenable(dev_info);
if (ret) {
printk(KERN_ERR
"Buffer not started:"
"ring preenable failed\n");
goto error_ret;
}
}
if (ring->access.request_update) {
ret = ring->access.request_update(ring);
if (ret) {
printk(KERN_INFO
"Buffer not started:"
"ring parameter update failed\n");
goto error_ret;
}
}
if (ring->access.mark_in_use)
ring->access.mark_in_use(ring);
/* Definitely possible for devices to support both of these.*/
if (dev_info->modes & INDIO_RING_TRIGGERED) {
if (!dev_info->trig) {
printk(KERN_INFO
"Buffer not started: no trigger\n");
ret = -EINVAL;
if (ring->access.unmark_in_use)
ring->access.unmark_in_use(ring);
goto error_ret;
}
dev_info->currentmode = INDIO_RING_TRIGGERED;
} else if (dev_info->modes & INDIO_RING_HARDWARE_BUFFER)
dev_info->currentmode = INDIO_RING_HARDWARE_BUFFER;
else { /* should never be reached */
ret = -EINVAL;
goto error_ret;
}
if (ring->postenable) {
ret = ring->postenable(dev_info);
if (ret) {
printk(KERN_INFO
"Buffer not started:"
"postenable failed\n");
if (ring->access.unmark_in_use)
ring->access.unmark_in_use(ring);
dev_info->currentmode = previous_mode;
if (ring->postdisable)
ring->postdisable(dev_info);
goto error_ret;
}
}
} else {
if (ring->predisable) {
ret = ring->predisable(dev_info);
if (ret)
goto error_ret;
}
if (ring->access.unmark_in_use)
ring->access.unmark_in_use(ring);
dev_info->currentmode = INDIO_DIRECT_MODE;
if (ring->postdisable) {
ret = ring->postdisable(dev_info);
if (ret)
goto error_ret;
}
}
done:
mutex_unlock(&dev_info->mlock);
return len;
error_ret:
mutex_unlock(&dev_info->mlock);
return ret;
}
EXPORT_SYMBOL(iio_store_ring_enable);
ssize_t iio_show_ring_enable(struct device *dev,
struct device_attribute *attr,
char *buf)
{
struct iio_ring_buffer *ring = dev_get_drvdata(dev);
return sprintf(buf, "%d\n", !!(ring->indio_dev->currentmode
& INDIO_ALL_RING_MODES));
}
EXPORT_SYMBOL(iio_show_ring_enable);
ssize_t iio_scan_el_show(struct device *dev,
struct device_attribute *attr,
char *buf)
{
int ret;
struct iio_ring_buffer *ring = dev_get_drvdata(dev);
struct iio_scan_el *this_el = to_iio_scan_el(attr);
ret = iio_scan_mask_query(ring, this_el->number);
if (ret < 0)
return ret;
return sprintf(buf, "%d\n", ret);
}
EXPORT_SYMBOL(iio_scan_el_show);
ssize_t iio_scan_el_store(struct device *dev,
struct device_attribute *attr,
const char *buf,
size_t len)
{
int ret = 0;
bool state;
struct iio_ring_buffer *ring = dev_get_drvdata(dev);
struct iio_dev *indio_dev = ring->indio_dev;
struct iio_scan_el *this_el = to_iio_scan_el(attr);
state = !(buf[0] == '0');
mutex_lock(&indio_dev->mlock);
if (indio_dev->currentmode == INDIO_RING_TRIGGERED) {
ret = -EBUSY;
goto error_ret;
}
ret = iio_scan_mask_query(ring, this_el->number);
if (ret < 0)
goto error_ret;
if (!state && ret) {
ret = iio_scan_mask_clear(ring, this_el->number);
if (ret)
goto error_ret;
} else if (state && !ret) {
ret = iio_scan_mask_set(ring, this_el->number);
if (ret)
goto error_ret;
}
if (this_el->set_state)
ret = this_el->set_state(this_el, indio_dev, state);
error_ret:
mutex_unlock(&indio_dev->mlock);
return ret ? ret : len;
}
EXPORT_SYMBOL(iio_scan_el_store);
ssize_t iio_scan_el_ts_show(struct device *dev,
struct device_attribute *attr,
char *buf)
{
struct iio_ring_buffer *ring = dev_get_drvdata(dev);
return sprintf(buf, "%d\n", ring->scan_timestamp);
}
EXPORT_SYMBOL(iio_scan_el_ts_show);
ssize_t iio_scan_el_ts_store(struct device *dev,
struct device_attribute *attr,
const char *buf,
size_t len)
{
int ret = 0;
struct iio_ring_buffer *ring = dev_get_drvdata(dev);
struct iio_dev *indio_dev = ring->indio_dev;
bool state;
state = !(buf[0] == '0');
mutex_lock(&indio_dev->mlock);
if (indio_dev->currentmode == INDIO_RING_TRIGGERED) {
ret = -EBUSY;
goto error_ret;
}
ring->scan_timestamp = state;
error_ret:
mutex_unlock(&indio_dev->mlock);
return ret ? ret : len;
}
EXPORT_SYMBOL(iio_scan_el_ts_store);