[linux.git] / drivers / iio / kfifo_buf.c

#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 <linux/iio/kfifo_buf.h>
#include <linux/sched.h>

struct iio_kfifo {
	struct iio_buffer buffer;
	struct kfifo kf;
	int update_needed;
};

#define iio_to_kfifo(r) container_of(r, struct iio_kfifo, buffer)

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;

	return __kfifo_alloc((struct __kfifo *)&buf->kf, length,
			     bytes_per_datum, GFP_KERNEL);
}

static int iio_request_update_kfifo(struct iio_buffer *r)
{
	int ret = 0;
	struct iio_kfifo *buf = iio_to_kfifo(r);

	if (!buf->update_needed)
		goto error_ret;
	kfifo_free(&buf->kf);
	ret = __iio_allocate_kfifo(buf, buf->buffer.bytes_per_datum,
				   buf->buffer.length);
	r->stufftoread = false;
error_ret:
	return ret;
}

static int iio_get_length_kfifo(struct iio_buffer *r)
{
	return r->length;
}

static IIO_BUFFER_ENABLE_ATTR;
static IIO_BUFFER_LENGTH_ATTR;

static struct attribute *iio_kfifo_attributes[] = {
	&dev_attr_length.attr,
	&dev_attr_enable.attr,
	NULL,
};

static struct attribute_group iio_kfifo_attribute_group = {
	.attrs = iio_kfifo_attributes,
	.name = "buffer",
};

static int iio_get_bytes_per_datum_kfifo(struct iio_buffer *r)
{
	return r->bytes_per_datum;
}

static int iio_mark_update_needed_kfifo(struct iio_buffer *r)
{
	struct iio_kfifo *kf = iio_to_kfifo(r);
	kf->update_needed = true;
	return 0;
}

static int iio_set_bytes_per_datum_kfifo(struct iio_buffer *r, size_t bpd)
{
	if (r->bytes_per_datum != bpd) {
		r->bytes_per_datum = bpd;
		iio_mark_update_needed_kfifo(r);
	}
	return 0;
}

static int iio_set_length_kfifo(struct iio_buffer *r, int length)
{
	/* Avoid an invalid state */
	if (length < 2)
		length = 2;
	if (r->length != length) {
		r->length = length;
		iio_mark_update_needed_kfifo(r);
	}
	return 0;
}

static int iio_store_to_kfifo(struct iio_buffer *r,
			      u8 *data)
{
	int ret;
	struct iio_kfifo *kf = iio_to_kfifo(r);
	ret = kfifo_in(&kf->kf, data, 1);
	if (ret != 1)
		return -EBUSY;
	r->stufftoread = true;
	wake_up_interruptible(&r->pollq);

	return 0;
}

static int iio_read_first_n_kfifo(struct iio_buffer *r,
			   size_t n, char __user *buf)
{
	int ret, copied;
	struct iio_kfifo *kf = iio_to_kfifo(r);

	if (n < r->bytes_per_datum || r->bytes_per_datum == 0)
		return -EINVAL;

	ret = kfifo_to_user(&kf->kf, buf, n, &copied);
	if (ret < 0)
		return ret;

	if (kfifo_is_empty(&kf->kf))
		r->stufftoread = false;
	/* verify it is still empty to avoid race */
	if (!kfifo_is_empty(&kf->kf))
		r->stufftoread = true;

	return copied;
}

static const struct iio_buffer_access_funcs kfifo_access_funcs = {
	.store_to = &iio_store_to_kfifo,
	.read_first_n = &iio_read_first_n_kfifo,
	.request_update = &iio_request_update_kfifo,
	.get_bytes_per_datum = &iio_get_bytes_per_datum_kfifo,
	.set_bytes_per_datum = &iio_set_bytes_per_datum_kfifo,
	.get_length = &iio_get_length_kfifo,
	.set_length = &iio_set_length_kfifo,
};

struct iio_buffer *iio_kfifo_allocate(struct iio_dev *indio_dev)
{
	struct iio_kfifo *kf;

	kf = kzalloc(sizeof *kf, GFP_KERNEL);
	if (!kf)
		return NULL;
	kf->update_needed = true;
	iio_buffer_init(&kf->buffer);
	kf->buffer.attrs = &iio_kfifo_attribute_group;
	kf->buffer.access = &kfifo_access_funcs;
	kf->buffer.length = 2;
	return &kf->buffer;
}
EXPORT_SYMBOL(iio_kfifo_allocate);

void iio_kfifo_free(struct iio_buffer *r)
{
	kfree(iio_to_kfifo(r));
}
EXPORT_SYMBOL(iio_kfifo_free);

MODULE_LICENSE("GPL");
Commit	Line	Data
b174baf4 JC	1	#include <linux/slab.h>
	2	#include <linux/kernel.h>
	3	#include <linux/module.h>
	4	#include <linux/device.h>
	5	#include <linux/workqueue.h>
	6	#include <linux/kfifo.h>
	7	#include <linux/mutex.h>
06458e27	8	#include <linux/iio/kfifo_buf.h>
7c388ec1	9	#include <linux/sched.h>
b174baf4	10
a710cc77	11	struct iio_kfifo {
14555b14	12	struct iio_buffer buffer;
a710cc77	13	struct kfifo kf;
a710cc77	14	int update_needed;
a710cc77 JC	15	};
a710cc77 JC	16
14555b14	17	#define iio_to_kfifo(r) container_of(r, struct iio_kfifo, buffer)
5565a450	18
b174baf4 JC	19	static inline int __iio_allocate_kfifo(struct iio_kfifo *buf,
	20	int bytes_per_datum, int length)
	21	{
	22	if ((length == 0) \|\| (bytes_per_datum == 0))
	23	return -EINVAL;
	24
c559afbf JC	25	return __kfifo_alloc((struct __kfifo *)&buf->kf, length,
c559afbf JC	26	bytes_per_datum, GFP_KERNEL);
b174baf4 JC	27	}
b174baf4 JC	28
14555b14	29	static int iio_request_update_kfifo(struct iio_buffer *r)
b174baf4 JC	30	{
	31	int ret = 0;
	32	struct iio_kfifo *buf = iio_to_kfifo(r);
	33
b174baf4 JC	34	if (!buf->update_needed)
b174baf4 JC	35	goto error_ret;
b174baf4	36	kfifo_free(&buf->kf);
14555b14 JC	37	ret = __iio_allocate_kfifo(buf, buf->buffer.bytes_per_datum,
14555b14 JC	38	buf->buffer.length);
7c388ec1	39	r->stufftoread = false;
b174baf4	40	error_ret:
b174baf4 JC	41	return ret;
b174baf4 JC	42	}
b174baf4	43
14555b14	44	static int iio_get_length_kfifo(struct iio_buffer *r)
b174baf4 JC	45	{
	46	return r->length;
	47	}
b174baf4	48
14555b14	49	static IIO_BUFFER_ENABLE_ATTR;
14555b14	50	static IIO_BUFFER_LENGTH_ATTR;
b174baf4 JC	51
	52	static struct attribute *iio_kfifo_attributes[] = {
	53	&dev_attr_length.attr,
b174baf4 JC	54	&dev_attr_enable.attr,
	55	NULL,
	56	};
	57
	58	static struct attribute_group iio_kfifo_attribute_group = {
	59	.attrs = iio_kfifo_attributes,
1aa04278	60	.name = "buffer",
b174baf4 JC	61	};
b174baf4 JC	62
14555b14	63	static int iio_get_bytes_per_datum_kfifo(struct iio_buffer *r)
b174baf4 JC	64	{
	65	return r->bytes_per_datum;
	66	}
b174baf4	67
869871b5	68	static int iio_mark_update_needed_kfifo(struct iio_buffer *r)
b174baf4	69	{
869871b5 LPC	70	struct iio_kfifo *kf = iio_to_kfifo(r);
869871b5 LPC	71	kf->update_needed = true;
b174baf4 JC	72	return 0;
b174baf4 JC	73	}
b174baf4	74
869871b5	75	static int iio_set_bytes_per_datum_kfifo(struct iio_buffer *r, size_t bpd)
b174baf4	76	{
869871b5 LPC	77	if (r->bytes_per_datum != bpd) {
	78	r->bytes_per_datum = bpd;
	79	iio_mark_update_needed_kfifo(r);
	80	}
b174baf4 JC	81	return 0;
b174baf4 JC	82	}
b174baf4	83
14555b14	84	static int iio_set_length_kfifo(struct iio_buffer *r, int length)
b174baf4	85	{
7c388ec1 JC	86	/* Avoid an invalid state */
	87	if (length < 2)
	88	length = 2;
b174baf4 JC	89	if (r->length != length) {
b174baf4 JC	90	r->length = length;
869871b5	91	iio_mark_update_needed_kfifo(r);
b174baf4 JC	92	}
	93	return 0;
	94	}
b174baf4	95
14555b14	96	static int iio_store_to_kfifo(struct iio_buffer *r,
ce56ade6	97	u8 *data)
b174baf4 JC	98	{
	99	int ret;
	100	struct iio_kfifo *kf = iio_to_kfifo(r);
c559afbf JC	101	ret = kfifo_in(&kf->kf, data, 1);
c559afbf JC	102	if (ret != 1)
b174baf4	103	return -EBUSY;
7c388ec1 JC	104	r->stufftoread = true;
7c388ec1 JC	105	wake_up_interruptible(&r->pollq);
c559afbf	106
b174baf4 JC	107	return 0;
b174baf4 JC	108	}
b174baf4	109
14555b14	110	static int iio_read_first_n_kfifo(struct iio_buffer *r,
b26a2188	111	size_t n, char __user *buf)
b174baf4 JC	112	{
	113	int ret, copied;
	114	struct iio_kfifo *kf = iio_to_kfifo(r);
	115
08ce9b44	116	if (n < r->bytes_per_datum \|\| r->bytes_per_datum == 0)
8fe64955 LPC	117	return -EINVAL;
8fe64955 LPC	118
8fe64955	119	ret = kfifo_to_user(&kf->kf, buf, n, &copied);
08ce9b44 JC	120	if (ret < 0)
08ce9b44 JC	121	return ret;
b174baf4	122
7c388ec1 JC	123	if (kfifo_is_empty(&kf->kf))
	124	r->stufftoread = false;
	125	/* verify it is still empty to avoid race */
	126	if (!kfifo_is_empty(&kf->kf))
	127	r->stufftoread = true;
	128
b174baf4 JC	129	return copied;
b174baf4 JC	130	}
5565a450	131
7e632344	132	static const struct iio_buffer_access_funcs kfifo_access_funcs = {
5565a450 JC	133	.store_to = &iio_store_to_kfifo,
5565a450 JC	134	.read_first_n = &iio_read_first_n_kfifo,
5565a450 JC	135	.request_update = &iio_request_update_kfifo,
	136	.get_bytes_per_datum = &iio_get_bytes_per_datum_kfifo,
	137	.set_bytes_per_datum = &iio_set_bytes_per_datum_kfifo,
	138	.get_length = &iio_get_length_kfifo,
	139	.set_length = &iio_set_length_kfifo,
	140	};
7e632344 LPC	141
	142	struct iio_buffer iio_kfifo_allocate(struct iio_dev indio_dev)
	143	{
	144	struct iio_kfifo *kf;
	145
	146	kf = kzalloc(sizeof *kf, GFP_KERNEL);
	147	if (!kf)
	148	return NULL;
	149	kf->update_needed = true;
	150	iio_buffer_init(&kf->buffer);
	151	kf->buffer.attrs = &iio_kfifo_attribute_group;
	152	kf->buffer.access = &kfifo_access_funcs;
7c388ec1	153	kf->buffer.length = 2;
7e632344 LPC	154	return &kf->buffer;
	155	}
	156	EXPORT_SYMBOL(iio_kfifo_allocate);
	157
	158	void iio_kfifo_free(struct iio_buffer *r)
	159	{
	160	kfree(iio_to_kfifo(r));
	161	}
	162	EXPORT_SYMBOL(iio_kfifo_free);
5565a450	163
b174baf4	164	MODULE_LICENSE("GPL");