staging:iio:kfifo buffer implementation (b174baf4) · Commits · e / devices / android_kernel_oneplus_sm8150

drivers/staging/iio/Kconfig

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		@@ -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

drivers/staging/iio/Makefile

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Original line number	Diff line number	Diff line
		@@ -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/

drivers/staging/iio/kfifo_buf.c

0 → 100644

+196 −0

Original line number	Diff line number	Diff line
		#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");

drivers/staging/iio/kfifo_buf.h

0 → 100644

+56 −0

Original line number	Diff line number	Diff line

		#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);