1 files changed, 0 insertions, 366 deletions
diff --git a/drivers/staging/iio/ring_sw.c b/drivers/staging/iio/ring_sw.c
deleted file mode 100644
index 3a45f9a52de..00000000000
--- a/drivers/staging/iio/ring_sw.c
+++ /dev/null
@@ -1,366 +0,0 @@
-/* The industrial I/O simple minimally locked ring buffer.
- *
- * 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.
- */
-
-#include <linux/slab.h>
-#include <linux/kernel.h>
-#include <linux/module.h>
-#include <linux/device.h>
-#include <linux/workqueue.h>
-#include <linux/sched.h>
-#include <linux/poll.h>
-#include "ring_sw.h"
-#include <linux/iio/trigger.h>
-
-/**
- * struct iio_sw_ring_buffer - software ring buffer
- * @buf:		generic ring buffer elements
- * @data:		the ring buffer memory
- * @read_p:		read pointer (oldest available)
- * @write_p:		write pointer
- * @half_p:		half buffer length behind write_p (event generation)
- * @update_needed:	flag to indicate change in size requested
- *
- * Note that the first element of all ring buffers must be a
- * struct iio_buffer.
-**/
-struct iio_sw_ring_buffer {
-	struct iio_buffer  buf;
-	unsigned char		*data;
-	unsigned char		*read_p;
-	unsigned char		*write_p;
-	/* used to act as a point at which to signal an event */
-	unsigned char		*half_p;
-	int			update_needed;
-};
-
-#define iio_to_sw_ring(r) container_of(r, struct iio_sw_ring_buffer, buf)
-
-static inline int __iio_allocate_sw_ring_buffer(struct iio_sw_ring_buffer *ring,
-						int bytes_per_datum, int length)
-{
-	if ((length == 0) || (bytes_per_datum == 0))
-		return -EINVAL;
-	__iio_update_buffer(&ring->buf, bytes_per_datum, length);
-	ring->data = kmalloc(length*ring->buf.bytes_per_datum, GFP_ATOMIC);
-	ring->read_p = NULL;
-	ring->write_p = NULL;
-	ring->half_p = NULL;
-	return ring->data ? 0 : -ENOMEM;
-}
-
-static inline void __iio_free_sw_ring_buffer(struct iio_sw_ring_buffer *ring)
-{
-	kfree(ring->data);
-}
-
-/* Ring buffer related functionality */
-/* Store to ring is typically called in the bh of a data ready interrupt handler
- * in the device driver */
-/* Lock always held if their is a chance this may be called */
-/* Only one of these per ring may run concurrently - enforced by drivers */
-static int iio_store_to_sw_ring(struct iio_sw_ring_buffer *ring,
-				unsigned char *data)
-{
-	int ret = 0;
-	unsigned char *temp_ptr, *change_test_ptr;
-
-	/* initial store */
-	if (unlikely(ring->write_p == NULL)) {
-		ring->write_p = ring->data;
-		/* Doesn't actually matter if this is out of the set
-		 * as long as the read pointer is valid before this
-		 * passes it - guaranteed as set later in this function.
-		 */
-		ring->half_p = ring->data - ring->buf.length*ring->buf.bytes_per_datum/2;
-	}
-	/* Copy data to where ever the current write pointer says */
-	memcpy(ring->write_p, data, ring->buf.bytes_per_datum);
-	barrier();
-	/* Update the pointer used to get most recent value.
-	 * Always valid as either points to latest or second latest value.
-	 * Before this runs it is null and read attempts fail with -EAGAIN.
-	 */
-	barrier();
-	/* temp_ptr used to ensure we never have an invalid pointer
-	 * it may be slightly lagging, but never invalid
-	 */
-	temp_ptr = ring->write_p + ring->buf.bytes_per_datum;
-	/* End of ring, back to the beginning */
-	if (temp_ptr == ring->data + ring->buf.length*ring->buf.bytes_per_datum)
-		temp_ptr = ring->data;
-	/* Update the write pointer
-	 * always valid as long as this is the only function able to write.
-	 * Care needed with smp systems to ensure more than one ring fill
-	 * is never scheduled.
-	 */
-	ring->write_p = temp_ptr;
-
-	if (ring->read_p == NULL)
-		ring->read_p = ring->data;
-	/* Buffer full - move the read pointer and create / escalate
-	 * ring event */
-	/* Tricky case - if the read pointer moves before we adjust it.
-	 * Handle by not pushing if it has moved - may result in occasional
-	 * unnecessary buffer full events when it wasn't quite true.
-	 */
-	else if (ring->write_p == ring->read_p) {
-		change_test_ptr = ring->read_p;
-		temp_ptr = change_test_ptr + ring->buf.bytes_per_datum;
-		if (temp_ptr
-		    == ring->data + ring->buf.length*ring->buf.bytes_per_datum) {
-			temp_ptr = ring->data;
-		}
-		/* We are moving pointer on one because the ring is full.  Any
-		 * change to the read pointer will be this or greater.
-		 */
-		if (change_test_ptr == ring->read_p)
-			ring->read_p = temp_ptr;
-	}
-	/* investigate if our event barrier has been passed */
-	/* There are definite 'issues' with this and chances of
-	 * simultaneous read */
-	/* Also need to use loop count to ensure this only happens once */
-	ring->half_p += ring->buf.bytes_per_datum;
-	if (ring->half_p == ring->data + ring->buf.length*ring->buf.bytes_per_datum)
-		ring->half_p = ring->data;
-	if (ring->half_p == ring->read_p) {
-		ring->buf.stufftoread = true;
-		wake_up_interruptible(&ring->buf.pollq);
-	}
-	return ret;
-}
-
-static int iio_read_first_n_sw_rb(struct iio_buffer *r,
-				  size_t n, char __user *buf)
-{
-	struct iio_sw_ring_buffer *ring = iio_to_sw_ring(r);
-
-	u8 *initial_read_p, *initial_write_p, *current_read_p, *end_read_p;
-	u8 *data;
-	int ret, max_copied, bytes_to_rip, dead_offset;
-	size_t data_available, buffer_size;
-
-	/* A userspace program has probably made an error if it tries to
-	 * read something that is not a whole number of bpds.
-	 * Return an error.
-	 */
-	if (n % ring->buf.bytes_per_datum) {
-		ret = -EINVAL;
-		printk(KERN_INFO "Ring buffer read request not whole number of"
-		       "samples: Request bytes %zd, Current bytes per datum %d\n",
-		       n, ring->buf.bytes_per_datum);
-		goto error_ret;
-	}
-
-	buffer_size = ring->buf.bytes_per_datum*ring->buf.length;
-
-	/* Limit size to whole of ring buffer */
-	bytes_to_rip = min_t(size_t, buffer_size, n);
-
-	data = kmalloc(bytes_to_rip, GFP_KERNEL);
-	if (data == NULL) {
-		ret = -ENOMEM;
-		goto error_ret;
-	}
-
-	/* build local copy */
-	initial_read_p = ring->read_p;
-	if (unlikely(initial_read_p == NULL)) { /* No data here as yet */
-		ret = 0;
-		goto error_free_data_cpy;
-	}
-
-	initial_write_p = ring->write_p;
-
-	/* Need a consistent pair */
-	while ((initial_read_p != ring->read_p)
-	       || (initial_write_p != ring->write_p)) {
-		initial_read_p = ring->read_p;
-		initial_write_p = ring->write_p;
-	}
-	if (initial_write_p == initial_read_p) {
-		/* No new data available.*/
-		ret = 0;
-		goto error_free_data_cpy;
-	}
-
-	if (initial_write_p >= initial_read_p)
-		data_available = initial_write_p - initial_read_p;
-	else
-		data_available = buffer_size - (initial_read_p - initial_write_p);
-
-	if (data_available < bytes_to_rip)
-		bytes_to_rip = data_available;
-
-	if (initial_read_p + bytes_to_rip >= ring->data + buffer_size) {
-		max_copied = ring->data + buffer_size - initial_read_p;
-		memcpy(data, initial_read_p, max_copied);
-		memcpy(data + max_copied, ring->data, bytes_to_rip - max_copied);
-		end_read_p = ring->data + bytes_to_rip - max_copied;
-	} else {
-		memcpy(data, initial_read_p, bytes_to_rip);
-		end_read_p = initial_read_p + bytes_to_rip;
-	}
-
-	/* Now to verify which section was cleanly copied - i.e. how far
-	 * read pointer has been pushed */
-	current_read_p = ring->read_p;
-
-	if (initial_read_p <= current_read_p)
-		dead_offset = current_read_p - initial_read_p;
-	else
-		dead_offset = buffer_size - (initial_read_p - current_read_p);
-
-	/* possible issue if the initial write has been lapped or indeed
-	 * the point we were reading to has been passed */
-	/* No valid data read.
-	 * In this case the read pointer is already correct having been
-	 * pushed further than we would look. */
-	if (bytes_to_rip - dead_offset < 0) {
-		ret = 0;
-		goto error_free_data_cpy;
-	}
-
-	/* setup the next read position */
-	/* Beware, this may fail due to concurrency fun and games.
-	 * Possible that sufficient fill commands have run to push the read
-	 * pointer past where we would be after the rip. If this occurs, leave
-	 * it be.
-	 */
-	/* Tricky - deal with loops */
-
-	while (ring->read_p != end_read_p)
-		ring->read_p = end_read_p;
-
-	ret = bytes_to_rip - dead_offset;
-
-	if (copy_to_user(buf, data + dead_offset, ret))  {
-		ret =  -EFAULT;
-		goto error_free_data_cpy;
-	}
-
-	if (bytes_to_rip >= ring->buf.length*ring->buf.bytes_per_datum/2)
-		ring->buf.stufftoread = 0;
-
-error_free_data_cpy:
-	kfree(data);
-error_ret:
-
-	return ret;
-}
-
-static int iio_store_to_sw_rb(struct iio_buffer *r,
-			      u8 *data)
-{
-	struct iio_sw_ring_buffer *ring = iio_to_sw_ring(r);
-	return iio_store_to_sw_ring(ring, data);
-}
-
-static int iio_request_update_sw_rb(struct iio_buffer *r)
-{
-	int ret = 0;
-	struct iio_sw_ring_buffer *ring = iio_to_sw_ring(r);
-
-	r->stufftoread = false;
-	if (!ring->update_needed)
-		goto error_ret;
-	__iio_free_sw_ring_buffer(ring);
-	ret = __iio_allocate_sw_ring_buffer(ring, ring->buf.bytes_per_datum,
-					    ring->buf.length);
-error_ret:
-	return ret;
-}
-
-static int iio_get_bytes_per_datum_sw_rb(struct iio_buffer *r)
-{
-	struct iio_sw_ring_buffer *ring = iio_to_sw_ring(r);
-	return ring->buf.bytes_per_datum;
-}
-
-static int iio_mark_update_needed_sw_rb(struct iio_buffer *r)
-{
-	struct iio_sw_ring_buffer *ring = iio_to_sw_ring(r);
-	ring->update_needed = true;
-	return 0;
-}
-
-static int iio_set_bytes_per_datum_sw_rb(struct iio_buffer *r, size_t bpd)
-{
-	if (r->bytes_per_datum != bpd) {
-		r->bytes_per_datum = bpd;
-		iio_mark_update_needed_sw_rb(r);
-	}
-	return 0;
-}
-
-static int iio_get_length_sw_rb(struct iio_buffer *r)
-{
-	return r->length;
-}
-
-static int iio_set_length_sw_rb(struct iio_buffer *r, int length)
-{
-	if (r->length != length) {
-		r->length = length;
-		iio_mark_update_needed_sw_rb(r);
-	}
-	return 0;
-}
-
-static IIO_BUFFER_ENABLE_ATTR;
-static IIO_BUFFER_LENGTH_ATTR;
-
-/* Standard set of ring buffer attributes */
-static struct attribute *iio_ring_attributes[] = {
-	&dev_attr_length.attr,
-	&dev_attr_enable.attr,
-	NULL,
-};
-
-static struct attribute_group iio_ring_attribute_group = {
-	.attrs = iio_ring_attributes,
-	.name = "buffer",
-};
-
-static const struct iio_buffer_access_funcs ring_sw_access_funcs = {
-	.store_to = &iio_store_to_sw_rb,
-	.read_first_n = &iio_read_first_n_sw_rb,
-	.request_update = &iio_request_update_sw_rb,
-	.get_bytes_per_datum = &iio_get_bytes_per_datum_sw_rb,
-	.set_bytes_per_datum = &iio_set_bytes_per_datum_sw_rb,
-	.get_length = &iio_get_length_sw_rb,
-	.set_length = &iio_set_length_sw_rb,
-};
-
-struct iio_buffer *iio_sw_rb_allocate(struct iio_dev *indio_dev)
-{
-	struct iio_buffer *buf;
-	struct iio_sw_ring_buffer *ring;
-
-	ring = kzalloc(sizeof *ring, GFP_KERNEL);
-	if (!ring)
-		return NULL;
-	ring->update_needed = true;
-	buf = &ring->buf;
-	iio_buffer_init(buf);
-	buf->attrs = &iio_ring_attribute_group;
-	buf->access = &ring_sw_access_funcs;
-
-	return buf;
-}
-EXPORT_SYMBOL(iio_sw_rb_allocate);
-
-void iio_sw_rb_free(struct iio_buffer *r)
-{
-	kfree(iio_to_sw_ring(r));
-}
-EXPORT_SYMBOL(iio_sw_rb_free);
-
-MODULE_DESCRIPTION("Industrial I/O software ring buffer");
-MODULE_LICENSE("GPL");