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|
/* 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.
*
* Based on elements of hwmon and input subsystems.
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/idr.h>
#include <linux/kdev_t.h>
#include <linux/err.h>
#include <linux/device.h>
#include <linux/fs.h>
#include <linux/interrupt.h>
#include <linux/poll.h>
#include <linux/sched.h>
#include <linux/wait.h>
#include <linux/cdev.h>
#include "iio.h"
#include "trigger_consumer.h"
#define IIO_ID_PREFIX "device"
#define IIO_ID_FORMAT IIO_ID_PREFIX "%d"
/* IDR to assign each registered device a unique id*/
static DEFINE_IDR(iio_idr);
/* IDR for general event identifiers */
static DEFINE_IDR(iio_event_idr);
/* IDR to allocate character device minor numbers */
static DEFINE_IDR(iio_chrdev_idr);
/* Lock used to protect both of the above */
static DEFINE_SPINLOCK(iio_idr_lock);
dev_t iio_devt;
EXPORT_SYMBOL(iio_devt);
#define IIO_DEV_MAX 256
static char *iio_devnode(struct device *dev, mode_t *mode)
{
return kasprintf(GFP_KERNEL, "iio/%s", dev_name(dev));
}
struct class iio_class = {
.name = "iio",
.devnode = iio_devnode,
};
EXPORT_SYMBOL(iio_class);
void __iio_change_event(struct iio_detected_event_list *ev,
int ev_code,
s64 timestamp)
{
ev->ev.id = ev_code;
ev->ev.timestamp = timestamp;
}
EXPORT_SYMBOL(__iio_change_event);
/* Used both in the interrupt line put events and the ring buffer ones */
/* Note that in it's current form someone has to be listening before events
* are queued. Hence a client MUST open the chrdev before the ring buffer is
* switched on.
*/
int __iio_push_event(struct iio_event_interface *ev_int,
int ev_code,
s64 timestamp,
struct iio_shared_ev_pointer *
shared_pointer_p)
{
struct iio_detected_event_list *ev;
int ret = 0;
/* Does anyone care? */
mutex_lock(&ev_int->event_list_lock);
if (test_bit(IIO_BUSY_BIT_POS, &ev_int->handler.flags)) {
if (ev_int->current_events == ev_int->max_events) {
mutex_unlock(&ev_int->event_list_lock);
return 0;
}
ev = kmalloc(sizeof(*ev), GFP_KERNEL);
if (ev == NULL) {
ret = -ENOMEM;
mutex_unlock(&ev_int->event_list_lock);
goto error_ret;
}
ev->ev.id = ev_code;
ev->ev.timestamp = timestamp;
ev->shared_pointer = shared_pointer_p;
if (ev->shared_pointer)
shared_pointer_p->ev_p = ev;
list_add_tail(&ev->list, &ev_int->det_events.list);
ev_int->current_events++;
mutex_unlock(&ev_int->event_list_lock);
wake_up_interruptible(&ev_int->wait);
} else
mutex_unlock(&ev_int->event_list_lock);
error_ret:
return ret;
}
EXPORT_SYMBOL(__iio_push_event);
int iio_push_event(struct iio_dev *dev_info,
int ev_line,
int ev_code,
s64 timestamp)
{
return __iio_push_event(&dev_info->event_interfaces[ev_line],
ev_code, timestamp, NULL);
}
EXPORT_SYMBOL(iio_push_event);
/* Generic interrupt line interrupt handler */
irqreturn_t iio_interrupt_handler(int irq, void *_int_info)
{
struct iio_interrupt *int_info = _int_info;
struct iio_dev *dev_info = int_info->dev_info;
struct iio_event_handler_list *p;
s64 time_ns;
unsigned long flags;
spin_lock_irqsave(&int_info->ev_list_lock, flags);
if (list_empty(&int_info->ev_list)) {
spin_unlock_irqrestore(&int_info->ev_list_lock, flags);
return IRQ_NONE;
}
time_ns = iio_get_time_ns();
/* detect single element list*/
if (list_is_singular(&int_info->ev_list)) {
disable_irq_nosync(irq);
p = list_first_entry(&int_info->ev_list,
struct iio_event_handler_list,
list);
/* single event handler - maybe shared */
p->handler(dev_info, 1, time_ns, !(p->refcount > 1));
} else
list_for_each_entry(p, &int_info->ev_list, list) {
disable_irq_nosync(irq);
p->handler(dev_info, 1, time_ns, 0);
}
spin_unlock_irqrestore(&int_info->ev_list_lock, flags);
return IRQ_HANDLED;
}
static struct iio_interrupt *iio_allocate_interrupt(void)
{
struct iio_interrupt *i = kmalloc(sizeof *i, GFP_KERNEL);
if (i) {
spin_lock_init(&i->ev_list_lock);
INIT_LIST_HEAD(&i->ev_list);
}
return i;
}
/* Confirming the validity of supplied irq is left to drivers.*/
int iio_register_interrupt_line(unsigned int irq,
struct iio_dev *dev_info,
int line_number,
unsigned long type,
const char *name)
{
int ret;
dev_info->interrupts[line_number] = iio_allocate_interrupt();
if (dev_info->interrupts[line_number] == NULL) {
ret = -ENOMEM;
goto error_ret;
}
dev_info->interrupts[line_number]->line_number = line_number;
dev_info->interrupts[line_number]->irq = irq;
dev_info->interrupts[line_number]->dev_info = dev_info;
/* Possibly only request on demand?
* Can see this may complicate the handling of interrupts.
* However, with this approach we might end up handling lots of
* events no-one cares about.*/
ret = request_irq(irq,
&iio_interrupt_handler,
type,
name,
dev_info->interrupts[line_number]);
error_ret:
return ret;
}
EXPORT_SYMBOL(iio_register_interrupt_line);
/* This turns up an awful lot */
ssize_t iio_read_const_attr(struct device *dev,
struct device_attribute *attr,
char *buf)
{
return sprintf(buf, "%s\n", to_iio_const_attr(attr)->string);
}
EXPORT_SYMBOL(iio_read_const_attr);
/* Before this runs the interrupt generator must have been disabled */
void iio_unregister_interrupt_line(struct iio_dev *dev_info, int line_number)
{
/* make sure the interrupt handlers are all done */
flush_scheduled_work();
free_irq(dev_info->interrupts[line_number]->irq,
dev_info->interrupts[line_number]);
kfree(dev_info->interrupts[line_number]);
}
EXPORT_SYMBOL(iio_unregister_interrupt_line);
/* Reference counted add and remove */
void iio_add_event_to_list(struct iio_event_handler_list *el,
struct list_head *head)
{
unsigned long flags;
struct iio_interrupt *inter = to_iio_interrupt(head);
/* take mutex to protect this element */
mutex_lock(&el->exist_lock);
if (el->refcount == 0) {
/* Take the event list spin lock */
spin_lock_irqsave(&inter->ev_list_lock, flags);
list_add(&el->list, head);
spin_unlock_irqrestore(&inter->ev_list_lock, flags);
}
el->refcount++;
mutex_unlock(&el->exist_lock);
}
EXPORT_SYMBOL(iio_add_event_to_list);
void iio_remove_event_from_list(struct iio_event_handler_list *el,
struct list_head *head)
{
unsigned long flags;
struct iio_interrupt *inter = to_iio_interrupt(head);
mutex_lock(&el->exist_lock);
el->refcount--;
if (el->refcount == 0) {
/* Take the event list spin lock */
spin_lock_irqsave(&inter->ev_list_lock, flags);
list_del_init(&el->list);
spin_unlock_irqrestore(&inter->ev_list_lock, flags);
}
mutex_unlock(&el->exist_lock);
}
EXPORT_SYMBOL(iio_remove_event_from_list);
ssize_t iio_event_chrdev_read(struct file *filep,
char *buf,
size_t count,
loff_t *f_ps)
{
struct iio_event_interface *ev_int = filep->private_data;
struct iio_detected_event_list *el;
int ret;
size_t len;
mutex_lock(&ev_int->event_list_lock);
if (list_empty(&ev_int->det_events.list)) {
if (filep->f_flags & O_NONBLOCK) {
ret = -EAGAIN;
goto error_mutex_unlock;
}
mutex_unlock(&ev_int->event_list_lock);
/* Blocking on device; waiting for something to be there */
ret = wait_event_interruptible(ev_int->wait,
!list_empty(&ev_int
->det_events.list));
if (ret)
goto error_ret;
/* Single access device so noone else can get the data */
mutex_lock(&ev_int->event_list_lock);
}
el = list_first_entry(&ev_int->det_events.list,
struct iio_detected_event_list,
list);
len = sizeof el->ev;
if (copy_to_user(buf, &(el->ev), len)) {
ret = -EFAULT;
goto error_mutex_unlock;
}
list_del(&el->list);
ev_int->current_events--;
mutex_unlock(&ev_int->event_list_lock);
/*
* Possible concurency issue if an update of this event is on its way
* through. May lead to new even being removed whilst the reported event
* was the unescalated event. In typical use case this is not a problem
* as userspace will say read half the buffer due to a 50% full event
* which would make the correct 100% full incorrect anyway.
*/
spin_lock(&el->shared_pointer->lock);
if (el->shared_pointer)
(el->shared_pointer->ev_p) = NULL;
spin_unlock(&el->shared_pointer->lock);
kfree(el);
return len;
error_mutex_unlock:
mutex_unlock(&ev_int->event_list_lock);
error_ret:
return ret;
}
int iio_event_chrdev_release(struct inode *inode, struct file *filep)
{
struct iio_handler *hand = iio_cdev_to_handler(inode->i_cdev);
struct iio_event_interface *ev_int = hand->private;
struct iio_detected_event_list *el, *t;
mutex_lock(&ev_int->event_list_lock);
clear_bit(IIO_BUSY_BIT_POS, &ev_int->handler.flags);
/*
* In order to maintain a clean state for reopening,
* clear out any awaiting events. The mask will prevent
* any new __iio_push_event calls running.
*/
list_for_each_entry_safe(el, t, &ev_int->det_events.list, list) {
list_del(&el->list);
kfree(el);
}
mutex_unlock(&ev_int->event_list_lock);
return 0;
}
int iio_event_chrdev_open(struct inode *inode, struct file *filep)
{
struct iio_handler *hand = iio_cdev_to_handler(inode->i_cdev);
struct iio_event_interface *ev_int = hand->private;
mutex_lock(&ev_int->event_list_lock);
if (test_and_set_bit(IIO_BUSY_BIT_POS, &hand->flags)) {
fops_put(filep->f_op);
mutex_unlock(&ev_int->event_list_lock);
return -EBUSY;
}
filep->private_data = hand->private;
mutex_unlock(&ev_int->event_list_lock);
return 0;
}
static const struct file_operations iio_event_chrdev_fileops = {
.read = iio_event_chrdev_read,
.release = iio_event_chrdev_release,
.open = iio_event_chrdev_open,
.owner = THIS_MODULE,
};
static void iio_event_dev_release(struct device *dev)
{
struct iio_event_interface *ev_int
= container_of(dev, struct iio_event_interface, dev);
cdev_del(&ev_int->handler.chrdev);
iio_device_free_chrdev_minor(MINOR(dev->devt));
};
static struct device_type iio_event_type = {
.release = iio_event_dev_release,
};
int iio_device_get_chrdev_minor(void)
{
int ret, val;
idr_again:
if (unlikely(idr_pre_get(&iio_chrdev_idr, GFP_KERNEL) == 0))
return -ENOMEM;
spin_lock(&iio_idr_lock);
ret = idr_get_new(&iio_chrdev_idr, NULL, &val);
spin_unlock(&iio_idr_lock);
if (unlikely(ret == -EAGAIN))
goto idr_again;
else if (unlikely(ret))
return ret;
if (val > IIO_DEV_MAX)
return -ENOMEM;
return val;
}
void iio_device_free_chrdev_minor(int val)
{
spin_lock(&iio_idr_lock);
idr_remove(&iio_chrdev_idr, val);
spin_unlock(&iio_idr_lock);
}
int iio_setup_ev_int(struct iio_event_interface *ev_int,
const char *name,
struct module *owner,
struct device *dev)
{
int ret, minor;
ev_int->dev.class = &iio_class;
ev_int->dev.parent = dev;
ev_int->dev.type = &iio_event_type;
device_initialize(&ev_int->dev);
minor = iio_device_get_chrdev_minor();
if (minor < 0) {
ret = minor;
goto error_device_put;
}
ev_int->dev.devt = MKDEV(MAJOR(iio_devt), minor);
dev_set_name(&ev_int->dev, "%s", name);
ret = device_add(&ev_int->dev);
if (ret)
goto error_free_minor;
cdev_init(&ev_int->handler.chrdev, &iio_event_chrdev_fileops);
ev_int->handler.chrdev.owner = owner;
mutex_init(&ev_int->event_list_lock);
/* discussion point - make this variable? */
ev_int->max_events = 10;
ev_int->current_events = 0;
INIT_LIST_HEAD(&ev_int->det_events.list);
init_waitqueue_head(&ev_int->wait);
ev_int->handler.private = ev_int;
ev_int->handler.flags = 0;
ret = cdev_add(&ev_int->handler.chrdev, ev_int->dev.devt, 1);
if (ret)
goto error_unreg_device;
return 0;
error_unreg_device:
device_unregister(&ev_int->dev);
error_free_minor:
iio_device_free_chrdev_minor(minor);
error_device_put:
put_device(&ev_int->dev);
return ret;
}
void iio_free_ev_int(struct iio_event_interface *ev_int)
{
device_unregister(&ev_int->dev);
put_device(&ev_int->dev);
}
static int __init iio_dev_init(void)
{
int err;
err = alloc_chrdev_region(&iio_devt, 0, IIO_DEV_MAX, "iio");
if (err < 0)
printk(KERN_ERR "%s: failed to allocate char dev region\n",
__FILE__);
return err;
}
static void __exit iio_dev_exit(void)
{
if (iio_devt)
unregister_chrdev_region(iio_devt, IIO_DEV_MAX);
}
static int __init iio_init(void)
{
int ret;
/* Create sysfs class */
ret = class_register(&iio_class);
if (ret < 0) {
printk(KERN_ERR
"%s could not create sysfs class\n",
__FILE__);
goto error_nothing;
}
ret = iio_dev_init();
if (ret < 0)
goto error_unregister_class;
return 0;
error_unregister_class:
class_unregister(&iio_class);
error_nothing:
return ret;
}
static void __exit iio_exit(void)
{
iio_dev_exit();
class_unregister(&iio_class);
}
static int iio_device_register_sysfs(struct iio_dev *dev_info)
{
int ret = 0;
ret = sysfs_create_group(&dev_info->dev.kobj, dev_info->attrs);
if (ret) {
dev_err(dev_info->dev.parent,
"Failed to register sysfs hooks\n");
goto error_ret;
}
if (dev_info->scan_el_attrs) {
ret = sysfs_create_group(&dev_info->dev.kobj,
dev_info->scan_el_attrs);
if (ret)
dev_err(&dev_info->dev,
"Failed to add sysfs scan els\n");
}
error_ret:
return ret;
}
static void iio_device_unregister_sysfs(struct iio_dev *dev_info)
{
if (dev_info->scan_el_attrs)
sysfs_remove_group(&dev_info->dev.kobj,
dev_info->scan_el_attrs);
sysfs_remove_group(&dev_info->dev.kobj, dev_info->attrs);
}
int iio_get_new_idr_val(struct idr *this_idr)
{
int ret;
int val;
idr_again:
if (unlikely(idr_pre_get(this_idr, GFP_KERNEL) == 0))
return -ENOMEM;
spin_lock(&iio_idr_lock);
ret = idr_get_new(this_idr, NULL, &val);
spin_unlock(&iio_idr_lock);
if (unlikely(ret == -EAGAIN))
goto idr_again;
else if (unlikely(ret))
return ret;
return val;
}
EXPORT_SYMBOL(iio_get_new_idr_val);
void iio_free_idr_val(struct idr *this_idr, int id)
{
spin_lock(&iio_idr_lock);
idr_remove(this_idr, id);
spin_unlock(&iio_idr_lock);
}
EXPORT_SYMBOL(iio_free_idr_val);
static int iio_device_register_id(struct iio_dev *dev_info,
struct idr *this_idr)
{
dev_info->id = iio_get_new_idr_val(&iio_idr);
if (dev_info->id < 0)
return dev_info->id;
return 0;
}
static void iio_device_unregister_id(struct iio_dev *dev_info)
{
iio_free_idr_val(&iio_idr, dev_info->id);
}
static inline int __iio_add_event_config_attrs(struct iio_dev *dev_info, int i)
{
int ret;
/*p for adding, q for removing */
struct attribute **attrp, **attrq;
if (dev_info->event_conf_attrs && dev_info->event_conf_attrs[i].attrs) {
attrp = dev_info->event_conf_attrs[i].attrs;
while (*attrp) {
ret = sysfs_add_file_to_group(&dev_info->dev.kobj,
*attrp,
dev_info
->event_attrs[i].name);
if (ret)
goto error_ret;
attrp++;
}
}
return 0;
error_ret:
attrq = dev_info->event_conf_attrs[i].attrs;
while (attrq != attrp) {
sysfs_remove_file_from_group(&dev_info->dev.kobj,
*attrq,
dev_info->event_attrs[i].name);
attrq++;
}
return ret;
}
static inline int __iio_remove_event_config_attrs(struct iio_dev *dev_info,
int i)
{
struct attribute **attrq;
if (dev_info->event_conf_attrs
&& dev_info->event_conf_attrs[i].attrs) {
attrq = dev_info->event_conf_attrs[i].attrs;
while (*attrq) {
sysfs_remove_file_from_group(&dev_info->dev.kobj,
*attrq,
dev_info
->event_attrs[i].name);
attrq++;
}
}
return 0;
}
static int iio_device_register_eventset(struct iio_dev *dev_info)
{
int ret = 0, i, j;
if (dev_info->num_interrupt_lines == 0)
return 0;
dev_info->event_interfaces =
kzalloc(sizeof(struct iio_event_interface)
*dev_info->num_interrupt_lines,
GFP_KERNEL);
if (dev_info->event_interfaces == NULL) {
ret = -ENOMEM;
goto error_ret;
}
dev_info->interrupts = kzalloc(sizeof(struct iio_interrupt *)
*dev_info->num_interrupt_lines,
GFP_KERNEL);
if (dev_info->interrupts == NULL) {
ret = -ENOMEM;
goto error_free_event_interfaces;
}
for (i = 0; i < dev_info->num_interrupt_lines; i++) {
dev_info->event_interfaces[i].owner = dev_info->driver_module;
ret = iio_get_new_idr_val(&iio_event_idr);
if (ret)
goto error_free_setup_ev_ints;
else
dev_info->event_interfaces[i].id = ret;
snprintf(dev_info->event_interfaces[i]._name, 20,
"event_line%d",
dev_info->event_interfaces[i].id);
ret = iio_setup_ev_int(&dev_info->event_interfaces[i],
(const char *)(dev_info
->event_interfaces[i]
._name),
dev_info->driver_module,
&dev_info->dev);
if (ret) {
dev_err(&dev_info->dev,
"Could not get chrdev interface\n");
iio_free_idr_val(&iio_event_idr,
dev_info->event_interfaces[i].id);
goto error_free_setup_ev_ints;
}
}
for (i = 0; i < dev_info->num_interrupt_lines; i++) {
snprintf(dev_info->event_interfaces[i]._attrname, 20,
"event_line%d_sources", i);
dev_info->event_attrs[i].name
= (const char *)
(dev_info->event_interfaces[i]._attrname);
ret = sysfs_create_group(&dev_info->dev.kobj,
&dev_info->event_attrs[i]);
if (ret) {
dev_err(&dev_info->dev,
"Failed to register sysfs for event attrs");
goto error_remove_sysfs_interfaces;
}
}
for (i = 0; i < dev_info->num_interrupt_lines; i++) {
ret = __iio_add_event_config_attrs(dev_info, i);
if (ret)
goto error_unregister_config_attrs;
}
return 0;
error_unregister_config_attrs:
for (j = 0; j < i; j++)
__iio_remove_event_config_attrs(dev_info, i);
i = dev_info->num_interrupt_lines - 1;
error_remove_sysfs_interfaces:
for (j = 0; j < i; j++)
sysfs_remove_group(&dev_info->dev.kobj,
&dev_info->event_attrs[j]);
i = dev_info->num_interrupt_lines - 1;
error_free_setup_ev_ints:
for (j = 0; j < i; j++) {
iio_free_idr_val(&iio_event_idr,
dev_info->event_interfaces[i].id);
iio_free_ev_int(&dev_info->event_interfaces[j]);
}
kfree(dev_info->interrupts);
error_free_event_interfaces:
kfree(dev_info->event_interfaces);
error_ret:
return ret;
}
static void iio_device_unregister_eventset(struct iio_dev *dev_info)
{
int i;
if (dev_info->num_interrupt_lines == 0)
return;
for (i = 0; i < dev_info->num_interrupt_lines; i++)
sysfs_remove_group(&dev_info->dev.kobj,
&dev_info->event_attrs[i]);
for (i = 0; i < dev_info->num_interrupt_lines; i++) {
iio_free_idr_val(&iio_event_idr,
dev_info->event_interfaces[i].id);
iio_free_ev_int(&dev_info->event_interfaces[i]);
}
kfree(dev_info->interrupts);
kfree(dev_info->event_interfaces);
}
static void iio_dev_release(struct device *device)
{
struct iio_dev *dev = to_iio_dev(device);
iio_put();
kfree(dev);
}
static struct device_type iio_dev_type = {
.name = "iio_device",
.release = iio_dev_release,
};
struct iio_dev *iio_allocate_device(void)
{
struct iio_dev *dev = kzalloc(sizeof *dev, GFP_KERNEL);
if (dev) {
dev->dev.type = &iio_dev_type;
dev->dev.class = &iio_class;
device_initialize(&dev->dev);
dev_set_drvdata(&dev->dev, (void *)dev);
mutex_init(&dev->mlock);
iio_get();
}
return dev;
}
EXPORT_SYMBOL(iio_allocate_device);
void iio_free_device(struct iio_dev *dev)
{
if (dev)
iio_put_device(dev);
}
EXPORT_SYMBOL(iio_free_device);
int iio_device_register(struct iio_dev *dev_info)
{
int ret;
ret = iio_device_register_id(dev_info, &iio_idr);
if (ret) {
dev_err(&dev_info->dev, "Failed to get id\n");
goto error_ret;
}
dev_set_name(&dev_info->dev, "device%d", dev_info->id);
ret = device_add(&dev_info->dev);
if (ret)
goto error_free_idr;
ret = iio_device_register_sysfs(dev_info);
if (ret) {
dev_err(dev_info->dev.parent,
"Failed to register sysfs interfaces\n");
goto error_del_device;
}
ret = iio_device_register_eventset(dev_info);
if (ret) {
dev_err(dev_info->dev.parent,
"Failed to register event set \n");
goto error_free_sysfs;
}
if (dev_info->modes & INDIO_RING_TRIGGERED)
iio_device_register_trigger_consumer(dev_info);
return 0;
error_free_sysfs:
iio_device_unregister_sysfs(dev_info);
error_del_device:
device_del(&dev_info->dev);
error_free_idr:
iio_device_unregister_id(dev_info);
error_ret:
return ret;
}
EXPORT_SYMBOL(iio_device_register);
void iio_device_unregister(struct iio_dev *dev_info)
{
if (dev_info->modes & INDIO_RING_TRIGGERED)
iio_device_unregister_trigger_consumer(dev_info);
iio_device_unregister_eventset(dev_info);
iio_device_unregister_sysfs(dev_info);
iio_device_unregister_id(dev_info);
device_unregister(&dev_info->dev);
}
EXPORT_SYMBOL(iio_device_unregister);
void iio_put(void)
{
module_put(THIS_MODULE);
}
void iio_get(void)
{
__module_get(THIS_MODULE);
}
subsys_initcall(iio_init);
module_exit(iio_exit);
MODULE_AUTHOR("Jonathan Cameron <jic23@cam.ac.uk>");
MODULE_DESCRIPTION("Industrial I/O core");
MODULE_LICENSE("GPL");
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