Techwizz/kernel-fxtec-pro1x
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity

staging:iio:kfifo buffer implementation

Browse source 
A very simple use of a kfifo as an alternative for the ring_sw

Signed-off-by: Jonathan Cameron <jic23@cam.ac.uk>
Tested-by: Michael Hennerich <michael.hennerich@analog.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This commit is contained in:
Jonathan Cameron 2011-02-11 13:09:10 +00:00 committed by Greg Kroah-Hartman
parent d5857d65b5
commit b174baf4b7
4 changed files with 262 additions and 0 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

9
drivers/staging/iio/Kconfig
View file

@ -29,6 +29,15 @@ config IIO_SW_RING
with the intention that some devices would be able to write
in interrupt context.
config IIO_KFIFO_BUF
select IIO_TRIGGER
tristate "Industrial I/O buffering based on kfifo"
help
A simple fifo based on kfifo. Use this if you want a fifo
rather than a ring buffer. Note that this currently provides
no buffer events so it is up to userspace to work out how
often to read from the buffer.
endif # IIO_RINGBUFFER
config IIO_TRIGGER

1
drivers/staging/iio/Makefile
View file

@ -8,6 +8,7 @@ industrialio-$(CONFIG_IIO_RING_BUFFER) += industrialio-ring.o
industrialio-$(CONFIG_IIO_TRIGGER) += industrialio-trigger.o
obj-$(CONFIG_IIO_SW_RING) += ring_sw.o
obj-$(CONFIG_IIO_KFIFO_BUF) += kfifo_buf.o
obj-y += accel/
obj-y += adc/

196
drivers/staging/iio/kfifo_buf.c Normal file
View file

@ -0,0 +1,196 @@
#include <linux/slab.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/device.h>
#include <linux/workqueue.h>
#include <linux/kfifo.h>
#include <linux/mutex.h>
#include "kfifo_buf.h"
static inline int __iio_allocate_kfifo(struct iio_kfifo *buf,
int bytes_per_datum, int length)
{
if ((length == 0) || (bytes_per_datum == 0))
return -EINVAL;
__iio_update_ring_buffer(&buf->ring, bytes_per_datum, length);
return kfifo_alloc(&buf->kf, bytes_per_datum*length, GFP_KERNEL);
}
int iio_request_update_kfifo(struct iio_ring_buffer *r)
{
int ret = 0;
struct iio_kfifo *buf = iio_to_kfifo(r);
mutex_lock(&buf->use_lock);
if (!buf->update_needed)
goto error_ret;
if (buf->use_count) {
ret = -EAGAIN;
goto error_ret;
}
kfifo_free(&buf->kf);
ret = __iio_allocate_kfifo(buf, buf->ring.bytes_per_datum,
buf->ring.length);
error_ret:
mutex_unlock(&buf->use_lock);
return ret;
}
EXPORT_SYMBOL(iio_request_update_kfifo);
void iio_mark_kfifo_in_use(struct iio_ring_buffer *r)
{
struct iio_kfifo *buf = iio_to_kfifo(r);
mutex_lock(&buf->use_lock);
buf->use_count++;
mutex_unlock(&buf->use_lock);
}
EXPORT_SYMBOL(iio_mark_kfifo_in_use);
void iio_unmark_kfifo_in_use(struct iio_ring_buffer *r)
{
struct iio_kfifo *buf = iio_to_kfifo(r);
mutex_lock(&buf->use_lock);
buf->use_count--;
mutex_unlock(&buf->use_lock);
}
EXPORT_SYMBOL(iio_unmark_kfifo_in_use);
int iio_get_length_kfifo(struct iio_ring_buffer *r)
{
return r->length;
}
EXPORT_SYMBOL(iio_get_length_kfifo);
static inline void __iio_init_kfifo(struct iio_kfifo *kf)
{
mutex_init(&kf->use_lock);
}
static IIO_RING_ENABLE_ATTR;
static IIO_RING_BYTES_PER_DATUM_ATTR;
static IIO_RING_LENGTH_ATTR;
static struct attribute *iio_kfifo_attributes[] = {
&dev_attr_length.attr,
&dev_attr_bytes_per_datum.attr,
&dev_attr_enable.attr,
NULL,
};
static struct attribute_group iio_kfifo_attribute_group = {
.attrs = iio_kfifo_attributes,
};
static const struct attribute_group *iio_kfifo_attribute_groups[] = {
&iio_kfifo_attribute_group,
NULL
};
static void iio_kfifo_release(struct device *dev)
{
struct iio_ring_buffer *r = to_iio_ring_buffer(dev);
struct iio_kfifo *kf = iio_to_kfifo(r);
kfifo_free(&kf->kf);
kfree(kf);
}
static struct device_type iio_kfifo_type = {
.release = iio_kfifo_release,
.groups = iio_kfifo_attribute_groups,
};
struct iio_ring_buffer *iio_kfifo_allocate(struct iio_dev *indio_dev)
{
struct iio_kfifo *kf;
kf = kzalloc(sizeof *kf, GFP_KERNEL);
if (!kf)
return NULL;
iio_ring_buffer_init(&kf->ring, indio_dev);
__iio_init_kfifo(kf);
kf->ring.dev.type = &iio_kfifo_type;
device_initialize(&kf->ring.dev);
kf->ring.dev.parent = &indio_dev->dev;
kf->ring.dev.bus = &iio_bus_type;
dev_set_drvdata(&kf->ring.dev, (void *)&(kf->ring));
return &kf->ring;
}
EXPORT_SYMBOL(iio_kfifo_allocate);
int iio_get_bytes_per_datum_kfifo(struct iio_ring_buffer *r)
{
return r->bytes_per_datum;
}
EXPORT_SYMBOL(iio_get_bytes_per_datum_kfifo);
int iio_set_bytes_per_datum_kfifo(struct iio_ring_buffer *r, size_t bpd)
{
if (r->bytes_per_datum != bpd) {
r->bytes_per_datum = bpd;
if (r->access.mark_param_change)
r->access.mark_param_change(r);
}
return 0;
}
EXPORT_SYMBOL(iio_set_bytes_per_datum_kfifo);
int iio_mark_update_needed_kfifo(struct iio_ring_buffer *r)
{
struct iio_kfifo *kf = iio_to_kfifo(r);
kf->update_needed = true;
return 0;
}
EXPORT_SYMBOL(iio_mark_update_needed_kfifo);
int iio_set_length_kfifo(struct iio_ring_buffer *r, int length)
{
if (r->length != length) {
r->length = length;
if (r->access.mark_param_change)
r->access.mark_param_change(r);
}
return 0;
}
EXPORT_SYMBOL(iio_set_length_kfifo);
void iio_kfifo_free(struct iio_ring_buffer *r)
{
if (r)
iio_put_ring_buffer(r);
}
EXPORT_SYMBOL(iio_kfifo_free);
int iio_store_to_kfifo(struct iio_ring_buffer *r, u8 *data, s64 timestamp)
{
int ret;
struct iio_kfifo *kf = iio_to_kfifo(r);
u8 *datal = kmalloc(r->bytes_per_datum, GFP_KERNEL);
memcpy(datal, data, r->bytes_per_datum - sizeof(timestamp));
memcpy(datal + r->bytes_per_datum - sizeof(timestamp),
&timestamp, sizeof(timestamp));
ret = kfifo_in(&kf->kf, data, r->bytes_per_datum);
if (ret != r->bytes_per_datum) {
kfree(datal);
return -EBUSY;
}
kfree(datal);
return 0;
}
EXPORT_SYMBOL(iio_store_to_kfifo);
int iio_rip_kfifo(struct iio_ring_buffer *r,
size_t count, char __user *buf, int *deadoffset)
{
int ret, copied;
struct iio_kfifo *kf = iio_to_kfifo(r);
*deadoffset = 0;
ret = kfifo_to_user(&kf->kf, buf, r->bytes_per_datum*count, &copied);
return copied;
}
EXPORT_SYMBOL(iio_rip_kfifo);
MODULE_LICENSE("GPL");

56
drivers/staging/iio/kfifo_buf.h Normal file
View file

@ -0,0 +1,56 @@
#include <linux/kfifo.h>
#include "iio.h"
#include "ring_generic.h"
struct iio_kfifo {
struct iio_ring_buffer ring;
struct kfifo kf;
int use_count;
int update_needed;
struct mutex use_lock;
};
#define iio_to_kfifo(r) container_of(r, struct iio_kfifo, ring)
int iio_create_kfifo(struct iio_ring_buffer **r);
int iio_init_kfifo(struct iio_ring_buffer *r, struct iio_dev *indio_dev);
void iio_exit_kfifo(struct iio_ring_buffer *r);
void iio_free_kfifo(struct iio_ring_buffer *r);
void iio_mark_kfifo_in_use(struct iio_ring_buffer *r);
void iio_unmark_kfifo_in_use(struct iio_ring_buffer *r);
int iio_store_to_kfifo(struct iio_ring_buffer *r, u8 *data, s64 timestamp);
int iio_rip_kfifo(struct iio_ring_buffer *r,
size_t count,
char __user *buf,
int *dead_offset);
int iio_request_update_kfifo(struct iio_ring_buffer *r);
int iio_mark_update_needed_kfifo(struct iio_ring_buffer *r);
int iio_get_bytes_per_datum_kfifo(struct iio_ring_buffer *r);
int iio_set_bytes_per_datum_kfifo(struct iio_ring_buffer *r, size_t bpd);
int iio_get_length_kfifo(struct iio_ring_buffer *r);
int iio_set_length_kfifo(struct iio_ring_buffer *r, int length);
static inline void iio_kfifo_register_funcs(struct iio_ring_access_funcs *ra)
{
ra->mark_in_use = &iio_mark_kfifo_in_use;
ra->unmark_in_use = &iio_unmark_kfifo_in_use;
ra->store_to = &iio_store_to_kfifo;
ra->rip_lots = &iio_rip_kfifo;
ra->mark_param_change = &iio_mark_update_needed_kfifo;
ra->request_update = &iio_request_update_kfifo;
ra->get_bytes_per_datum = &iio_get_bytes_per_datum_kfifo;
ra->set_bytes_per_datum = &iio_set_bytes_per_datum_kfifo;
ra->get_length = &iio_get_length_kfifo;
ra->set_length = &iio_set_length_kfifo;
};
struct iio_ring_buffer *iio_kfifo_allocate(struct iio_dev *indio_dev);
void iio_kfifo_free(struct iio_ring_buffer *r);