// SPDX-License-Identifier: GPL-2.0-only
/* The industrial I/O core
*
* Copyright (c) 2008 Jonathan Cameron
*
* Handling of buffer allocation / resizing.
*
* Things to look at here.
* - Better memory allocation techniques?
* - Alternative access techniques?
*/
#include <linux/atomic.h>
#include <linux/anon_inodes.h>
#include <linux/cleanup.h>
#include <linux/kernel.h>
#include <linux/export.h>
#include <linux/device.h>
#include <linux/dma-buf.h>
#include <linux/dma-fence.h>
#include <linux/dma-resv.h>
#include <linux/file.h>
#include <linux/fs.h>
#include <linux/cdev.h>
#include <linux/slab.h>
#include <linux/mm.h>
#include <linux/poll.h>
#include <linux/sched/signal.h>
#include <linux/iio/iio.h>
#include <linux/iio/iio-opaque.h>
#include "iio_core.h"
#include "iio_core_trigger.h"
#include <linux/iio/sysfs.h>
#include <linux/iio/buffer.h>
#include <linux/iio/buffer_impl.h>
#define DMABUF_ENQUEUE_TIMEOUT_MS 5000
MODULE_IMPORT_NS(DMA_BUF);
struct iio_dmabuf_priv {
struct list_head entry;
struct kref ref;
struct iio_buffer *buffer;
struct iio_dma_buffer_block *block;
u64 context;
/* Spinlock used for locking the dma_fence */
spinlock_t lock;
struct dma_buf_attachment *attach;
struct sg_table *sgt;
enum dma_data_direction dir;
atomic_t seqno;
};
struct iio_dma_fence {
struct dma_fence base;
struct iio_dmabuf_priv *priv;
struct work_struct work;
};
static const char * const iio_endian_prefix[] = {
[IIO_BE] = "be",
[IIO_LE] = "le",
};
static bool iio_buffer_is_active(struct iio_buffer *buf)
{
return !list_empty(&buf->buffer_list);
}
static size_t iio_buffer_data_available(struct iio_buffer *buf)
{
return buf->access->data_available(buf);
}
static int iio_buffer_flush_hwfifo(struct iio_dev *indio_dev,
struct iio_buffer *buf, size_t required)
{
if (!indio_dev->info->hwfifo_flush_to_buffer)
return -ENODEV;
return indio_dev->info->hwfifo_flush_to_buffer(indio_dev, required);
}
static bool iio_buffer_ready(struct iio_dev *indio_dev, struct iio_buffer *buf,
size_t to_wait, int to_flush)
{
size_t avail;
int flushed = 0;
/* wakeup if the device was unregistered */
if (!indio_dev->info)
return true;
/* drain the buffer if it was disabled */
if (!iio_buffer_is_active(buf)) {
to_wait = min_t(size_t, to_wait, 1);
to_flush = 0;
}
avail = iio_buffer_data_available(buf);
if (avail >= to_wait) {
/* force a flush for non-blocking reads */
if (!to_wait && avail < to_flush)
iio_buffer_flush_hwfifo(indio_dev, buf,
to_flush - avail);
return true;
}
if (to_flush)
flushed = iio_buffer_flush_hwfifo(indio_dev, buf,
to_wait - avail);
if (flushed <= 0)
return false;
if (avail + flushed >= to_wait)
return true;
return false;
}
/**
* iio_buffer_read() - chrdev read for buffer access
* @filp: File structure pointer for the char device
* @buf: Destination buffer for iio buffer read
* @n: First n bytes to read
* @f_ps: Long offset provided by the user as a seek position
*
* This function relies on all buffer implementations having an
* iio_buffer as their first element.
*
* Return: negative values corresponding to error codes or ret != 0
* for ending the reading activity
**/
static ssize_t iio_buffer_read(struct file *filp, char __user *buf,
size_t n, loff_t *f_ps)
{
struct iio_dev_buffer_pair *ib = filp->private_data;
struct iio_buffer *rb = ib->buffer;
struct iio_dev *indio_dev = ib->indio_dev;
DEFINE_WAIT_FUNC(wait, woken_wake_function);
size_t datum_size;
size_t to_wait;
int ret = 0;
if (!indio_dev->info)
return -ENODEV;
if (!rb || !rb->access->read)
return -EINVAL;
if (rb->direction != IIO_BUFFER_DIRECTION_IN)
return -EPERM;
datum_size = rb->bytes_per_datum;
/*
* If datum_size is 0 there will never be anything to read from the
* buffer, so signal end of file now.
*/
if (!datum_size)
return 0;
if (filp->f_flags & O_NONBLOCK)
to_wait = 0;
else
to_wait = min_t(size_t, n / datum_size, rb->watermark);
add_wait_queue(&rb->pollq, &wait);
do {
if (!indio_dev->info) {
ret = -ENODEV;
break;
}
if (!iio_buffer_ready(indio_dev, rb, to_wait, n / datum_size)) {
if (signal_pending(current)) {
ret = -ERESTARTSYS;
break;
}
wait_woken(&wait, TASK_INTERRUPTIBLE,
MAX_SCHEDULE_TIMEOUT);
continue;
}
ret = rb->access->read(rb, n, buf);
if (ret == 0 && (filp->f_flags & O_NONBLOCK))
ret = -EAGAIN;
} while (ret == 0);
remove_wait_queue(&rb->pollq, &wait);
return ret;
}
static size_t iio_buffer_space_available(struct iio_buffer *buf)
{
if (buf->access->space_available)
return buf->access->space_available(buf);
return SIZE_MAX;
}
static ssize_t iio_buffer_write(struct file *filp, const char __user *buf,
size_t n, loff_t *f_ps)
{
struct iio_dev_buffer_pair *ib = filp->private_data;
struct iio_buffer *rb = ib->buffer;
struct iio_dev *indio_dev = ib->indio_dev;
DEFINE_WAIT_FUNC(wait, woken_wake_function);
int ret = 0;
size_t written;
if (!indio_dev->info)
return -ENODEV;
if (!rb || !rb->access->write)
return -EINVAL;
if (rb->direction != IIO_BUFFER_DIRECTION_OUT)
return -EPERM;
written = 0;
add_wait_queue(&rb->pollq, &wait);
do {
if (!indio_dev->info)
return -ENODEV;
if (!iio_buffer_space_available(rb)) {
if (signal_pending(current)) {
ret = -ERESTARTSYS;
break;
}
if (filp->f_flags & O_NONBLOCK) {
if (!written)
ret = -EAGAIN;
break;
}
wait_woken(&wait, TASK_INTERRUPTIBLE,
MAX_SCHEDULE_TIMEOUT);
continue;
}
ret = rb->access->write(rb, n - written, buf + written);
if (ret < 0)
break;
written += ret;
} while (written != n);
remove_wait_queue(&rb->pollq, &wait);
return ret < 0 ? ret : written;
}
/**
* iio_buffer_poll() - poll the buffer to find out if it has data
* @filp: File structure pointer for device access
* @wait: Poll table structure pointer for which the driver adds
* a wait queue
*
* Return: (EPOLLIN | EPOLLRDNORM) if data is available for reading
* or 0 for other cases
*/
static __poll_t iio_buffer_poll(struct file *filp,
struct poll_table_struct *wait)
{
struct iio_dev_buffer_pair *ib = filp->private_data;
struct iio_buffer *rb = ib->buffer;
struct iio_dev *indio_dev = ib->indio_dev;
if (!indio_dev->info || !rb)
return 0;
poll_wait(filp, &rb->pollq, wait);
switch (rb->direction) {
case IIO_BUFFER_DIRECTION_IN:
if (iio_buffer_ready(indio_dev, rb, rb->watermark, 0))
return EPOLLIN | EPOLLRDNORM;
break;
case IIO_BUFFER_DIRECTION_OUT:
if (iio_buffer_space_available(rb))
return EPOLLOUT | EPOLLWRNORM;
break;
}
return 0;
}
ssize_t iio_buffer_read_wrapper(struct file *filp, char __user *buf,
size_t n, loff_t *f_ps)
{
struct iio_dev_buffer_pair *ib = filp->private_data;
struct iio_buffer *rb = ib->buffer;
/* check if buffer was opened through new API */
if (test_bit(IIO_BUSY_BIT_POS, &rb->flags))
return -EBUSY;
return iio_buffer_read(filp, buf, n, f_ps);
}
ssize_t iio_buffer_write_wrapper(struct file *filp, const char __user *buf,
size_t n, loff_t *f_ps)
{
struct iio_dev_buffer_pair *ib = filp->private_data;
struct iio_buffer *rb = ib->buffer;
/* check if buffer was opened through new API */
if (test_bit(IIO_BUSY_BIT_POS, &rb->flags))
return -EBUSY;
return iio_buffer_write(filp, buf, n, f_ps);
}
__poll_t iio_buffer_poll_wrapper(struct file *filp,
struct poll_table_struct *wait)
{
struct iio_dev_buffer_pair *ib = filp->private_data;
struct iio_buffer *rb = ib->buffer;
/* check if buffer was opened through new API */
if (test_bit(IIO_BUSY_BIT_POS, &rb->flags))
return 0;
return iio_buffer_poll(filp, wait);
}
/**
* iio_buffer_wakeup_poll - Wakes up the buffer waitqueue
* @indio_dev: The IIO device
*
* Wakes up the event waitqueue used for poll(). Should usually
* be called when the device is unregistered.
*/
void iio_buffer_wakeup_poll(struct iio_dev *indio_dev)
{
struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
struct iio_buffer *buffer;
unsigned int i;
for (i = 0; i < iio_dev_opaque->attached_buffers_cnt; i++) {
buffer = iio_dev_opaque->attached_buffers[i];
wake_up(&buffer->pollq);
}
}
int iio_pop_from_buffer(struct iio_buffer *buffer, void *data)
{
if (!buffer || !buffer->access || !buffer->access->remove_from)
return -EINVAL;
return buffer->access->remove_from(buffer, data);
}
EXPORT_SYMBOL_GPL(iio_pop_from_buffer);
void iio_buffer_init(struct iio_buffer *buffer)
{
INIT_LIST_HEAD(&buffer->demux_list);
INIT_LIST_HEAD(&buffer->buffer_list);
INIT_LIST_HEAD(&buffer->dmabufs);
mutex_init(&buffer->dmabufs_mutex);
init_waitqueue_head(&buffer->pollq);
kref_init(&buffer->ref);
if (!buffer->watermark)
buffer->watermark = 1;
}
EXPORT_SYMBOL(iio_buffer_init);
void iio_device_detach_buffers(struct iio_dev *indio_dev)
{
struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
struct iio_buffer *buffer;
unsigned int i;
for (i = 0; i < iio_dev_opaque->attached_buffers_cnt; i++) {
buffer = iio_dev_opaque->attached_buffers[i];
iio_buffer_put(buffer);
}
kfree(iio_dev_opaque->attached_buffers);
}
static ssize_t iio_show_scan_index(struct device *dev,
struct device_attribute *attr,
char *buf)
{
return sysfs_emit(buf, "%u\n", to_iio_dev_attr(attr)->c->scan_index);
}
static ssize_t iio_show_fixed_type(struct device *dev,
struct device_attribute *attr,
char *buf)
{
struct iio_dev *indio_dev = dev_to_iio_dev(dev);
struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
const struct iio_scan_type *scan_type;
u8 type;
scan_type = iio_get_current_scan_type(indio_dev, this_attr->c);
if (IS_ERR(scan_type))
return PTR_ERR(scan_type);
type = scan_type->endianness;
if (type == IIO_CPU) {
#ifdef __LITTLE_ENDIAN
type = IIO_LE;
#else
type = IIO_BE;
#endif
}
if (scan_type->repeat > 1)
return sysfs_emit(buf, "%s:%c%d/%dX%d>>%u\n",
iio_endian_prefix[type],
scan_type->sign,
scan_type->realbits,
scan_type->storagebits,
scan_type->repeat,
scan_type->shift);
else
return sysfs_emit(buf, "%s:%c%d/%d>>%u\n",
iio_endian_prefix[type],
scan_type->sign,
scan_type->realbits,
scan_type->storagebits,
scan_type->shift);
}
static ssize_t iio_scan_el_show(struct device *dev,
struct device_attribute *attr,
char *buf)
{
int ret;
struct iio_buffer *buffer = to_iio_dev_attr(attr)->buffer;
/* Ensure ret is 0 or 1. */
ret = !!test_bit(to_iio_dev_attr(attr)->address,
buffer->scan_mask);
return sysfs_emit(buf, "%d\n", ret);
}
/* Note NULL used as error indicator as it doesn't make sense. */
static const unsigned long *iio_scan_mask_match(const unsigned long *av_masks,
unsigned int masklength,
const unsigned long *mask,
bool strict)
{
if (bitmap_empty(mask, masklength))
return NULL;
/*
* The condition here do not handle multi-long masks correctly.
* It only checks the first long to be zero, and will use such mask
* as a terminator even if there was bits set after the first long.
*
* Correct check would require using:
* while (!bitmap_empty(av_masks, masklength))
* instead. This is potentially hazardous because the
* avaliable_scan_masks is a zero terminated array of longs - and
* using the proper bitmap_empty() check for multi-long wide masks
* would require the array to be terminated with multiple zero longs -
* which is not such an usual pattern.
*
* As writing of this no multi-long wide masks were found in-tree, so
* the simple while (*av_masks) check is working.
*/
while (*av_masks) {
if (strict) {
if (bitmap_equal(mask, av_masks, masklength))
return av_masks;
} else {
if (bitmap_subset(mask, av_masks, masklength))
return av_masks;
}
av_masks += BITS_TO_LONGS(masklength);
}
return NULL;
}
static bool iio_validate_scan_mask(struct iio_dev *indio_dev,
const unsigned long *mask)
{
if (!indio_dev->setup_ops->validate_scan_mask)
return true;
return indio_dev->setup_ops->validate_scan_mask(indio_dev, mask);
}
/**
* iio_scan_mask_set() - set particular bit in the scan mask
* @indio_dev: the iio device
* @buffer: the buffer whose scan mask we are interested in
* @bit: the bit to be set.
*
* Note that at this point we have no way of knowing what other
* buffers might request, hence this code only verifies that the
* individual buffers request is plausible.
*/
static int iio_scan_mask_set(struct iio_dev *indio_dev,
struct iio_buffer *buffer, int bit)
{
unsigned int masklength = iio_get_masklength(indio_dev);
const unsigned long *mask;
unsigned long *trialmask;
if (!masklength) {
WARN(1, "Trying to set scanmask prior to registering buffer\n");
return -EINVAL;
}
trialmask = bitmap_alloc(masklength, GFP_KERNEL);
if (!trialmask)
return -ENOMEM;
bitmap_copy(trialmask, buffer->scan_mask, masklength);
set_bit(bit, trialmask);
if (!iio_validate_scan_mask(indio_dev, trialmask))
goto err_invalid_mask;
if (indio_dev->available_scan_masks) {
mask = iio_scan_mask_match(indio_dev->available_scan_masks,
masklength, trialmask, false);
if (!mask)
goto err_invalid_mask;
}
bitmap_copy(buffer->scan_mask, trialmask, masklength);
bitmap_free(trialmask);
return 0;
err_invalid_mask:
bitmap_free(trialmask);
return -EINVAL;
}
static int iio_scan_mask_clear(struct iio_buffer *buffer, int bit)
{
clear_bit(bit, buffer->scan_mask);
return 0;
}
static int iio_scan_mask_query(struct iio_dev *indio_dev,
struct iio_buffer *buffer, int bit)
{
if (bit > iio_get_masklength(indio_dev))
return -EINVAL;
if (!buffer->scan_mask)
return 0;
/* Ensure return value is 0 or 1. */
return !!test_bit(bit, buffer->scan_mask);
};
static ssize_t iio_scan_el_store(struct device *dev,
struct device_attribute *attr,
const char *buf,
size_t len)
{
int ret;
bool state;
struct iio_dev *indio_dev = dev_to_iio_dev(dev);
struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
struct iio_buffer *buffer = this_attr->buffer;
ret = kstrtobool(buf, &state);
if (ret < 0)
return ret;
guard(mutex)(&iio_dev_opaque->mlock);
if (iio_buffer_is_active(buffer))
return -EBUSY;
ret = iio_scan_mask_query(indio_dev, buffer, this_attr->address);
if (ret < 0)
return ret;
if (state && ret)
return len;
if (state)
ret = iio_scan_mask_set(indio_dev, buffer, this_attr->address);
else
ret = iio_scan_mask_clear(buffer, this_attr->address);
if (ret)
return ret;
return len;
}
static ssize_t iio_scan_el_ts_show(struct device *dev,
struct device_attribute *attr,
char *buf)
{
struct iio_buffer *buffer = to_iio_dev_attr(attr)->buffer;
return sysfs_emit(buf, "%d\n", buffer->scan_timestamp);
}
static ssize_t iio_scan_el_ts_store(struct device *dev,
struct device_attribute *attr,
const char *buf,
size_t len)
{
int ret;
struct iio_dev *indio_dev = dev_to_iio_dev(dev);
struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
struct iio_buffer *buffer = to_iio_dev_attr(attr)->buffer;
bool state;
ret = kstrtobool(buf, &state);
if (ret < 0)
return ret;
guard(mutex)(&iio_dev_opaque->mlock);
if (iio_buffer_is_active(buffer))
return -EBUSY;
buffer->scan_timestamp = state;
return len;
}
static int iio_buffer_add_channel_sysfs(struct iio_dev *indio_dev,
struct iio_buffer *buffer,
const struct iio_chan_spec *chan)
{
int ret, attrcount = 0;
ret = __iio_add_chan_devattr("index",
chan,
&iio_show_scan_index,
NULL,
0,
IIO_SEPARATE,
&indio_dev->dev,
buffer,
&buffer->buffer_attr_list);
if (ret)
return ret;
attrcount++;
ret = __iio_add_chan_devattr("type",
chan,
&iio_show_fixed_type,
NULL,
0,
IIO_SEPARATE,
&indio_dev->dev,
buffer,
&buffer->buffer_attr_list);
if (ret)
return ret;
attrcount++;
if (chan->type != IIO_TIMESTAMP)
ret = __iio_add_chan_devattr("en",
chan,
&iio_scan_el_show,
&iio_scan_el_store,
chan->scan_index,
IIO_SEPARATE,
&indio_dev->dev,
buffer,
&buffer->buffer_attr_list);
else
ret = __iio_add_chan_devattr("en",
chan,
&iio_scan_el_ts_show,
&iio_scan_el_ts_store,
chan->scan_index,
IIO_SEPARATE,
&indio_dev->dev,
buffer,
&buffer->buffer_attr_list);
if (ret)
return ret;
attrcount++;
ret = attrcount;
return ret;
}
static ssize_t length_show(struct device *dev, struct device_attribute *attr,
char *buf)
{
struct iio_buffer *buffer = to_iio_dev_attr(attr)->buffer;
return sysfs_emit(buf, "%d\n", buffer->length);
}
static ssize_t length_store(struct device *dev, struct device_attribute *attr,
const char *buf, size_t len)
{
struct iio_dev *indio_dev = dev_to_iio_dev(dev);
struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
struct iio_buffer *buffer = to_iio_dev_attr(attr)->buffer;
unsigned int val;
int ret;
ret = kstrtouint(buf, 10, &val);
if (ret)
return ret;
if (val == buffer->length)
return len;
guard(mutex)(&iio_dev_opaque->mlock);
if (iio_buffer_is_active(buffer))
return -EBUSY;
buffer->access->set_length(buffer, val);
if (buffer->length && buffer->length < buffer->watermark)
buffer->watermark = buffer->length;
return len;
}
static ssize_t enable_show(struct device *dev, struct device_attribute *attr,
char *buf)
{
struct iio_buffer *buffer = to_iio_dev_attr(attr)->buffer;
return sysfs_emit(buf, "%d\n", iio_buffer_is_active(buffer));
}
static int iio_storage_bytes_for_si(struct iio_dev *indio_dev,
unsigned int scan_index)
{
const struct iio_chan_spec *ch;
const struct iio_scan_type *scan_type;
unsigned int bytes;
ch = iio_find_channel_from_si(indio_dev, scan_index);
scan_type = iio_get_current_scan_type(indio_dev, ch);
if (IS_ERR(scan_type))
return PTR_ERR(scan_type);
bytes = scan_type->storagebits / 8;
if (scan_type->repeat > 1)
bytes *= scan_type->repeat;
return bytes;
}
static int iio_storage_bytes_for_timestamp(struct iio_dev *indio_dev)
{
struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
return iio_storage_bytes_for_si(indio_dev,
iio_dev_opaque->scan_index_timestamp);
}
static int iio_compute_scan_bytes(struct iio_dev *indio_dev,
const unsigned long *mask, bool timestamp)
{
unsigned int bytes = 0;
int length, i, largest = 0;
/* How much space will the demuxed element take? */
for_each_set_bit(i, mask, iio_get_masklength(indio_dev)) {
length = iio_storage_bytes_for_si(indio_dev, i);
if (length < 0)
return length;
bytes = ALIGN(bytes, length);
bytes += length;
largest = max(largest, length);
}
if (timestamp) {
length = iio_storage_bytes_for_timestamp(indio_dev);
if (length < 0)
return length;
bytes = ALIGN(bytes, length);
bytes += length;
largest = max(largest, length);
}
bytes = ALIGN(bytes, largest);
return bytes;
}
static void iio_buffer_activate(struct iio_dev *indio_dev,
struct iio_buffer *buffer)
{
struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
iio_buffer_get(buffer);
list_add(&buffer->buffer_list, &iio_dev_opaque->buffer_list);
}
static void iio_buffer_deactivate(struct iio_buffer *buffer)
{
list_del_init(&buffer->buffer_list);
wake_up_interruptible(&buffer->pollq);
iio_buffer_put(buffer);
}
static void iio_buffer_deactivate_all(struct iio_dev *indio_dev)
{
struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
struct iio_buffer *buffer, *_buffer;
list_for_each_entry_safe(buffer, _buffer,
&iio_dev_opaque->buffer_list, buffer_list)
iio_buffer_deactivate(buffer);
}
static int iio_buffer_enable(struct iio_buffer *buffer,
struct iio_dev *indio_dev)
{
if (!buffer->access->enable)
return 0;
return buffer->access->enable(buffer, indio_dev);
}
static int iio_buffer_disable(struct iio_buffer *buffer,
struct iio_dev *indio_dev)
{
if (!buffer->access->disable)
return 0;
return buffer->access->disable(buffer, indio_dev);
}
static void iio_buffer_update_bytes_per_datum(struct iio_dev *indio_dev,
struct iio_buffer *buffer)
{
unsigned int bytes;
if (!buffer->access->set_bytes_per_datum)
return;
bytes = iio_compute_scan_bytes(indio_dev, buffer->scan_mask,
buffer->scan_timestamp);
buffer->access->set_bytes_per_datum(buffer, bytes);
}
static int iio_buffer_request_update(struct iio_dev *indio_dev,
struct iio_buffer *buffer)
{
int ret;
iio_buffer_update_bytes_per_datum(indio_dev, buffer);
if (buffer->access->request_update) {
ret = buffer->access->request_update(buffer);
if (ret) {
dev_dbg(&indio_dev->dev,
"Buffer not started: buffer parameter update failed (%d)\n",
ret);
return ret;
}
}
return 0;
}
static void iio_free_scan_mask(struct iio_dev *indio_dev,
const unsigned long *mask)
{
/* If the mask is dynamically allocated free it, otherwise do nothing */
if (!indio_dev->available_scan_masks)
bitmap_free(mask);
}
struct iio_device_config {
unsigned int mode;
unsigned int watermark;
const unsigned long *scan_mask;
unsigned int scan_bytes;
bool scan_timestamp;
};
static int iio_verify_update(struct iio_dev *indio_dev,
struct iio_buffer *insert_buffer,
struct iio_buffer *remove_buffer,
struct iio_device_config *config)
{
struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
unsigned int masklength = iio_get_masklength(indio_dev);
unsigned long *compound_mask;
const unsigned long *scan_mask;
bool strict_scanmask = false;
struct iio_buffer *buffer;
bool scan_timestamp;
unsigned int modes;
if (insert_buffer &&
bitmap_empty(insert_buffer->scan_mask, masklength)) {
dev_dbg(&indio_dev->dev,
"At least one scan element must be enabled first\n");
return -EINVAL;
}
memset(config, 0, sizeof(*config));
config->watermark = ~0;
/*
* If there is just one buffer and we are removing it there is nothing
* to verify.
*/
if (remove_buffer && !insert_buffer &&
list_is_singular(&iio_dev_opaque->buffer_list))
return 0;
modes = indio_dev->modes;
list_for_each_entry(buffer, &iio_dev_opaque->buffer_list, buffer_list) {
if (buffer == remove_buffer)
continue;
modes &= buffer->access->modes;
config->watermark = min(config->watermark, buffer->watermark);
}
if (insert_buffer) {
modes &= insert_buffer->access->modes;
config->watermark = min(config->watermark,
insert_buffer->watermark);
}
/* Definitely possible for devices to support both of these. */
if ((modes & INDIO_BUFFER_TRIGGERED) && indio_dev->trig) {
config->mode = INDIO_BUFFER_TRIGGERED;
} else if (modes & INDIO_BUFFER_HARDWARE) {
/*
* Keep things simple for now and only allow a single buffer to
* be connected in hardware mode.
*/
if (insert_buffer && !list_empty(&iio_dev_opaque->buffer_list))
return -EINVAL;
config->mode = INDIO_BUFFER_HARDWARE;
strict_scanmask = true;
} else if (modes & INDIO_BUFFER_SOFTWARE) {
config->mode = INDIO_BUFFER_SOFTWARE;
} else {
/* Can only occur on first buffer */
if (indio_dev->modes & INDIO_BUFFER_TRIGGERED)
dev_dbg(&indio_dev->dev, "Buffer not started: no trigger\n");
return -EINVAL;
}
/* What scan mask do we actually have? */
compound_mask = bitmap_zalloc(masklength, GFP_KERNEL);
if (!compound_mask)
return -ENOMEM;
scan_timestamp = false;
list_for_each_entry(buffer, &iio_dev_opaque->buffer_list, buffer_list) {
if (buffer == remove_buffer)
continue;
bitmap_or(compound_mask, compound_mask, buffer->scan_mask,
masklength);
scan_timestamp |= buffer->scan_timestamp;
}
if (insert_buffer) {
bitmap_or(compound_mask, compound_mask,
insert_buffer->scan_mask, masklength);
scan_timestamp |= insert_buffer->scan_timestamp;
}
if (indio_dev->available_scan_masks) {
scan_mask = iio_scan_mask_match(indio_dev->available_scan_masks,
masklength, compound_mask,
strict_scanmask);
bitmap_free(compound_mask);
if (!scan_mask)
return -EINVAL;
} else {
scan_mask = compound_mask;
}
config->scan_bytes = iio_compute_scan_bytes(indio_dev,
scan_mask, scan_timestamp);
config->scan_mask = scan_mask;
config->scan_timestamp = scan_timestamp;
return 0;
}
/**
* struct iio_demux_table - table describing demux memcpy ops
* @from: index to copy from
* @to: index to copy to
* @length: how many bytes to copy
* @l: list head used for management
*/
struct iio_demux_table {
unsigned int from;
unsigned int to;
unsigned int length;
struct list_head l;
};
static void iio_buffer_demux_free(struct iio_buffer *buffer)
{
struct iio_demux_table *p, *q;
list_for_each_entry_safe(p, q, &buffer->demux_list, l) {
list_del(&p->l);
kfree(p);
}
}
static int iio_buffer_add_demux(struct iio_buffer *buffer,
struct iio_demux_table **p, unsigned int in_loc,
unsigned int out_loc,
unsigned int length)
{
if (*p && (*p)->from + (*p)->length == in_loc &&
(*p)->to + (*p)->length == out_loc) {
(*p)->length += length;
} else {
*p = kmalloc(sizeof(**p), GFP_KERNEL);
if (!(*p))
return -ENOMEM;
(*p)->from = in_loc;
(*p)->to = out_loc;
(*p)->length = length;
list_add_tail(&(*p)->l, &buffer->demux_list);
}
return 0;
}
static int iio_buffer_update_demux(struct iio_dev *indio_dev,
struct iio_buffer *buffer)
{
unsigned int masklength = iio_get_masklength(indio_dev);
int ret, in_ind = -1, out_ind, length;
unsigned int in_loc = 0, out_loc = 0;
struct iio_demux_table *p = NULL;
/* Clear out any old demux */
iio_buffer_demux_free(buffer);
kfree(buffer->demux_bounce);
buffer->demux_bounce = NULL;
/* First work out which scan mode we will actually have */
if (bitmap_equal(indio_dev->active_scan_mask,
buffer->scan_mask, masklength))
return 0;
/* Now we have the two masks, work from least sig and build up sizes */
for_each_set_bit(out_ind, buffer->scan_mask, masklength) {
in_ind = find_next_bit(indio_dev->active_scan_mask,
masklength, in_ind + 1);
while (in_ind != out_ind) {
ret = iio_storage_bytes_for_si(indio_dev, in_ind);
if (ret < 0)
goto error_clear_mux_table;
length = ret;
/* Make sure we are aligned */
in_loc = roundup(in_loc, length) + length;
in_ind = find_next_bit(indio_dev->active_scan_mask,
masklength, in_ind + 1);
}
ret = iio_storage_bytes_for_si(indio_dev, in_ind);
if (ret < 0)
goto error_clear_mux_table;
length = ret;
out_loc = roundup(out_loc, length);
in_loc = roundup(in_loc, length);
ret = iio_buffer_add_demux(buffer, &p, in_loc, out_loc, length);
if (ret)
goto error_clear_mux_table;
out_loc += length;
in_loc += length;
}
/* Relies on scan_timestamp being last */
if (buffer->scan_timestamp) {
ret = iio_storage_bytes_for_timestamp(indio_dev);
if (ret < 0)
goto error_clear_mux_table;
length = ret;
out_loc = roundup(out_loc, length);
in_loc = roundup(in_loc, length);
ret = iio_buffer_add_demux(buffer, &p, in_loc, out_loc, length);
if (ret)
goto error_clear_mux_table;
out_loc += length;
}
buffer->demux_bounce = kzalloc(out_loc, GFP_KERNEL);
if (!buffer->demux_bounce) {
ret = -ENOMEM;
goto error_clear_mux_table;
}
return 0;
error_clear_mux_table:
iio_buffer_demux_free(buffer);
return ret;
}
static int iio_update_demux(struct iio_dev *indio_dev)
{
struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
struct iio_buffer *buffer;
int ret;
list_for_each_entry(buffer, &iio_dev_opaque->buffer_list, buffer_list) {
ret = iio_buffer_update_demux(indio_dev, buffer);
if (ret < 0)
goto error_clear_mux_table;
}
return 0;
error_clear_mux_table:
list_for_each_entry(buffer, &iio_dev_opaque->buffer_list, buffer_list)
iio_buffer_demux_free(buffer);
return ret;
}
static int iio_enable_buffers(struct iio_dev *indio_dev,
struct iio_device_config *config)
{
struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
struct iio_buffer *buffer, *tmp = NULL;
int ret;
indio_dev->active_scan_mask = config->scan_mask;
indio_dev->scan_timestamp = config->scan_timestamp;
indio_dev->scan_bytes = config->scan_bytes;
iio_dev_opaque->currentmode = config->mode;
iio_update_demux(indio_dev);
/* Wind up again */
if (indio_dev->setup_ops->preenable) {
ret = indio_dev->setup_ops->preenable(indio_dev);
if (ret) {
dev_dbg(&indio_dev->dev,
"Buffer not started: buffer preenable failed (%d)\n", ret);
goto err_undo_config;
}
}
if (indio_dev->info->update_scan_mode) {
ret = indio_dev->info
->update_scan_mode(indio_dev,
indio_dev->active_scan_mask);
if (ret < 0) {
dev_dbg(&indio_dev->dev,
"Buffer not started: update scan mode failed (%d)\n",
ret);
goto err_run_postdisable;
}
}
if (indio_dev->info->hwfifo_set_watermark)
indio_dev->info->hwfifo_set_watermark(indio_dev,
config->watermark);
list_for_each_entry(buffer, &iio_dev_opaque->buffer_list, buffer_list) {
ret = iio_buffer_enable(buffer, indio_dev);
if (ret) {
tmp = buffer;
goto err_disable_buffers;
}
}
if (iio_dev_opaque->currentmode == INDIO_BUFFER_TRIGGERED) {
ret = iio_trigger_attach_poll_func(indio_dev->trig,
indio_dev->pollfunc);
if (ret)
goto err_disable_buffers;
}
if (indio_dev->setup_ops->postenable) {
ret = indio_dev->setup_ops->postenable(indio_dev);
if (ret) {
dev_dbg(&indio_dev->dev,
"Buffer not started: postenable failed (%d)\n", ret);
goto err_detach_pollfunc;
}
}
return 0;
err_detach_pollfunc:
if (iio_dev_opaque->currentmode == INDIO_BUFFER_TRIGGERED) {
iio_trigger_detach_poll_func(indio_dev->trig,
indio_dev->pollfunc);
}
err_disable_buffers:
buffer = list_prepare_entry(tmp, &iio_dev_opaque->buffer_list, buffer_list);
list_for_each_entry_continue_reverse(buffer, &iio_dev_opaque->buffer_list,
buffer_list)
iio_buffer_disable(buffer, indio_dev);
err_run_postdisable:
if (indio_dev->setup_ops->postdisable)
indio_dev->setup_ops->postdisable(indio_dev);
err_undo_config:
iio_dev_opaque->currentmode = INDIO_DIRECT_MODE;
indio_dev->active_scan_mask = NULL;
return ret;
}
static int iio_disable_buffers(struct iio_dev *indio_dev)
{
struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
struct iio_buffer *buffer;
int ret = 0;
int ret2;
/* Wind down existing buffers - iff there are any */
if (list_empty(&iio_dev_opaque->buffer_list))
return 0;
/*
* If things go wrong at some step in disable we still need to continue
* to perform the other steps, otherwise we leave the device in a
* inconsistent state. We return the error code for the first error we
* encountered.
*/
if (indio_dev->setup_ops->predisable) {
ret2 = indio_dev->setup_ops->predisable(indio_dev);
if (ret2 && !ret)
ret = ret2;
}
if (iio_dev_opaque->currentmode == INDIO_BUFFER_TRIGGERED) {
iio_trigger_detach_poll_func(indio_dev->trig,
indio_dev->pollfunc);
}
list_for_each_entry(buffer, &iio_dev_opaque->buffer_list, buffer_list) {
ret2 = iio_buffer_disable(buffer, indio_dev);
if (ret2 && !ret)
ret = ret2;
}
if (indio_dev->setup_ops->postdisable) {
ret2 = indio_dev->setup_ops->postdisable(indio_dev);
if (ret2 && !ret)
ret = ret2;
}
iio_free_scan_mask(indio_dev, indio_dev->active_scan_mask);
indio_dev->active_scan_mask = NULL;
iio_dev_opaque->currentmode = INDIO_DIRECT_MODE;
return ret;
}
static int __iio_update_buffers(struct iio_dev *indio_dev,
struct iio_buffer *insert_buffer,
struct iio_buffer *remove_buffer)
{
struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
struct iio_device_config new_config;
int ret;
ret = iio_verify_update(indio_dev, insert_buffer, remove_buffer,
&new_config);
if (ret)
return ret;
if (insert_buffer) {
ret = iio_buffer_request_update(indio_dev, insert_buffer);
if (ret)
goto err_free_config;
}
ret = iio_disable_buffers(indio_dev);
if (ret)
goto err_deactivate_all;
if (remove_buffer)
iio_buffer_deactivate(remove_buffer);
if (insert_buffer)
iio_buffer_activate(indio_dev, insert_buffer);
/* If no buffers in list, we are done */
if (list_empty(&iio_dev_opaque->buffer_list))
return 0;
ret = iio_enable_buffers(indio_dev, &new_config);
if (ret)
goto err_deactivate_all;
return 0;
err_deactivate_all:
/*
* We've already verified that the config is valid earlier. If things go
* wrong in either enable or disable the most likely reason is an IO
* error from the device. In this case there is no good recovery
* strategy. Just make sure to disable everything and leave the device
* in a sane state. With a bit of luck the device might come back to
* life again later and userspace can try again.
*/
iio_buffer_deactivate_all(indio_dev);
err_free_config:
iio_free_scan_mask(indio_dev, new_config.scan_mask);
return ret;
}
int iio_update_buffers(struct iio_dev *indio_dev,
struct iio_buffer *insert_buffer,
struct iio_buffer *remove_buffer)
{
struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
if (insert_buffer == remove_buffer)
return 0;
if (insert_buffer &&
insert_buffer->direction == IIO_BUFFER_DIRECTION_OUT)
return -EINVAL;
guard(mutex)(&iio_dev_opaque->info_exist_lock);
guard(mutex)(&iio_dev_opaque->mlock);
if (insert_buffer && iio_buffer_is_active(insert_buffer))
insert_buffer = NULL;
if (remove_buffer && !iio_buffer_is_active(remove_buffer))
remove_buffer = NULL;
if (!insert_buffer && !remove_buffer)
return 0;
if (!indio_dev->info)
return -ENODEV;
return __iio_update_buffers(indio_dev, insert_buffer, remove_buffer);
}
EXPORT_SYMBOL_GPL(iio_update_buffers);
void iio_disable_all_buffers(struct iio_dev *indio_dev)
{
iio_disable_buffers(indio_dev);
iio_buffer_deactivate_all(indio_dev);
}
static ssize_t enable_store(struct device *dev, struct device_attribute *attr,
const char *buf, size_t len)
{
int ret;
bool requested_state;
struct iio_dev *indio_dev = dev_to_iio_dev(dev);
struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
struct iio_buffer *buffer = to_iio_dev_attr(attr)->buffer;
bool inlist;
ret = kstrtobool(buf, &requested_state);
if (ret < 0)
return ret;
guard(mutex)(&iio_dev_opaque->mlock);
/* Find out if it is in the list */
inlist = iio_buffer_is_active(buffer);
/* Already in desired state */
if (inlist == requested_state)
return len;
if (requested_state)
ret = __iio_update_buffers(indio_dev, buffer, NULL);
else
ret = __iio_update_buffers(indio_dev, NULL, buffer);
if (ret)
return ret;
return len;
}
static ssize_t watermark_show(struct device *dev, struct device_attribute *attr,
char *buf)
{
struct iio_buffer *buffer = to_iio_dev_attr(attr)->buffer;
return sysfs_emit(buf, "%u\n", buffer->watermark);
}
static ssize_t watermark_store(struct device *dev,
struct device_attribute *attr,
const char *buf, size_t len)
{
struct iio_dev *indio_dev = dev_to_iio_dev(dev);
struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
struct iio_buffer *buffer = to_iio_dev_attr(attr)->buffer;
unsigned int val;
int ret;
ret = kstrtouint(buf, 10, &val);
if (ret)
return ret;
if (!val)
return -EINVAL;
guard(mutex)(&iio_dev_opaque->mlock);
if (val > buffer->length)
return -EINVAL;
if (iio_buffer_is_active(buffer))
return -EBUSY;
buffer->watermark = val;
return len;
}
static ssize_t data_available_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct iio_buffer *buffer = to_iio_dev_attr(attr)->buffer;
return sysfs_emit(buf, "%zu\n", iio_buffer_data_available(buffer));
}
static ssize_t direction_show(struct device *dev,
struct device_attribute *attr,
char *buf)
{
struct iio_buffer *buffer = to_iio_dev_attr(attr)->buffer;
switch (buffer->direction) {
case IIO_BUFFER_DIRECTION_IN:
return sysfs_emit(buf, "in\n");
case IIO_BUFFER_DIRECTION_OUT:
return sysfs_emit(buf, "out\n");
default:
return -EINVAL;
}
}
static DEVICE_ATTR_RW(length);
static struct device_attribute dev_attr_length_ro = __ATTR_RO(length);
static DEVICE_ATTR_RW(enable);
static DEVICE_ATTR_RW(watermark);
static struct device_attribute dev_attr_watermark_ro = __ATTR_RO(watermark);
static DEVICE_ATTR_RO(data_available);
static DEVICE_ATTR_RO(direction);
/*
* When adding new attributes here, put the at the end, at least until
* the code that handles the length/length_ro & watermark/watermark_ro
* assignments gets cleaned up. Otherwise these can create some weird
* duplicate attributes errors under some setups.
*/
static struct attribute *iio_buffer_attrs[] = {
&dev_attr_length.attr,
&dev_attr_enable.attr,
&dev_attr_watermark.attr,
&dev_attr_data_available.attr,
&dev_attr_direction.attr,
};
#define to_dev_attr(_attr) container_of(_attr, struct device_attribute, attr)
static struct attribute *iio_buffer_wrap_attr(struct iio_buffer *buffer,
struct attribute *attr)
{
struct device_attribute *dattr = to_dev_attr(attr);
struct iio_dev_attr *iio_attr;
iio_attr = kzalloc(sizeof(*iio_attr), GFP_KERNEL);
if (!iio_attr)
return NULL;
iio_attr->buffer = buffer;
memcpy(&iio_attr->dev_attr, dattr, sizeof(iio_attr->dev_attr));
iio_attr->dev_attr.attr.name = kstrdup_const(attr->name, GFP_KERNEL);
if (!iio_attr->dev_attr.attr.name) {
kfree(iio_attr);
return NULL;
}
sysfs_attr_init(&iio_attr->dev_attr.attr);
list_add(&iio_attr->l, &buffer->buffer_attr_list);
return &iio_attr->dev_attr.attr;
}
static int iio_buffer_register_legacy_sysfs_groups(struct iio_dev *indio_dev,
struct attribute **buffer_attrs,
int buffer_attrcount,
int scan_el_attrcount)
{
struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
struct attribute_group *group;
struct attribute **attrs;
int ret;
attrs = kcalloc(buffer_attrcount + 1, sizeof(*attrs), GFP_KERNEL);
if (!attrs)
return -ENOMEM;
memcpy(attrs, buffer_attrs, buffer_attrcount * sizeof(*attrs));
group = &iio_dev_opaque->legacy_buffer_group;
group->attrs = attrs;
group->name = "buffer";
ret = iio_device_register_sysfs_group(indio_dev, group);
if (ret)
goto error_free_buffer_attrs;
attrs = kcalloc(scan_el_attrcount + 1, sizeof(*attrs), GFP_KERNEL);
if (!attrs) {
ret = -ENOMEM;
goto error_free_buffer_attrs;
}
memcpy(attrs, &buffer_attrs[buffer_attrcount],
scan_el_attrcount * sizeof(*attrs));
group = &iio_dev_opaque->legacy_scan_el_group;
group->attrs = attrs;
group->name = "scan_elements";
ret = iio_device_register_sysfs_group(indio_dev, group);
if (ret)
goto error_free_scan_el_attrs;
return 0;
error_free_scan_el_attrs:
kfree(iio_dev_opaque->legacy_scan_el_group.attrs);
error_free_buffer_attrs:
kfree(iio_dev_opaque->legacy_buffer_group.attrs);
return ret;
}
static void iio_buffer_unregister_legacy_sysfs_groups(struct iio_dev *indio_dev)
{
struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
kfree(iio_dev_opaque->legacy_buffer_group.attrs);
kfree(iio_dev_opaque->legacy_scan_el_group.attrs);
}
static void iio_buffer_dmabuf_release(struct kref *ref)
{
struct iio_dmabuf_priv *priv = container_of(ref, struct iio_dmabuf_priv, ref);
struct dma_buf_attachment *attach = priv->attach;
struct iio_buffer *buffer = priv->buffer;
struct dma_buf *dmabuf = attach->dmabuf;
dma_resv_lock(dmabuf->resv, NULL);
dma_buf_unmap_attachment(attach, priv->sgt, priv->dir);
dma_resv_unlock(dmabuf->resv);
buffer->access->detach_dmabuf(buffer, priv->block);
dma_buf_detach(attach->dmabuf, attach);
dma_buf_put(dmabuf);
kfree(priv);
}
static void iio_buffer_dmabuf_get(struct dma_buf_attachment *attach)
{
struct iio_dmabuf_priv *priv = attach->importer_priv;
kref_get(&priv->ref);
}
static void iio_buffer_dmabuf_put(struct dma_buf_attachment *attach)
{
struct iio_dmabuf_priv *priv = attach->importer_priv;
kref_put(&priv->ref, iio_buffer_dmabuf_release);
}
static int iio_buffer_chrdev_release(struct inode *inode, struct file *filep)
{
struct iio_dev_buffer_pair *ib = filep->private_data;
struct iio_dev *indio_dev = ib->indio_dev;
struct iio_buffer *buffer = ib->buffer;
struct iio_dmabuf_priv *priv, *tmp;
wake_up(&buffer->pollq);
guard(mutex)(&buffer->dmabufs_mutex);
/* Close all attached DMABUFs */
list_for_each_entry_safe(priv, tmp, &buffer->dmabufs, entry) {
list_del_init(&priv->entry);
iio_buffer_dmabuf_put(priv->attach);
}
kfree(ib);
clear_bit(IIO_BUSY_BIT_POS, &buffer->flags);
iio_device_put(indio_dev);
return 0;
}
static int iio_dma_resv_lock(struct dma_buf *dmabuf, bool nonblock)
{
if (!nonblock)
return dma_resv_lock_interruptible(dmabuf->resv, NULL);
if (!dma_resv_trylock(dmabuf->resv))
return -EBUSY;
return 0;
}
static struct dma_buf_attachment *
iio_buffer_find_attachment(struct iio_dev_buffer_pair *ib,
struct dma_buf *dmabuf, bool nonblock)
{
struct device *dev = ib->indio_dev->dev.parent;
struct iio_buffer *buffer = ib->buffer;
struct dma_buf_attachment *attach = NULL;
struct iio_dmabuf_priv *priv;
guard(mutex)(&buffer->dmabufs_mutex);
list_for_each_entry(priv, &buffer->dmabufs, entry) {
if (priv->attach->dev == dev
&& priv->attach->dmabuf == dmabuf) {
attach = priv->attach;
break;
}
}
if (attach)
iio_buffer_dmabuf_get(attach);
return attach ?: ERR_PTR(-EPERM);
}
static int iio_buffer_attach_dmabuf(struct iio_dev_buffer_pair *ib,
int __user *user_fd, bool nonblock)
{
struct iio_dev *indio_dev = ib->indio_dev;
struct iio_buffer *buffer = ib->buffer;
struct dma_buf_attachment *attach;
struct iio_dmabuf_priv *priv, *each;
struct dma_buf *dmabuf;
int err, fd;
if (!buffer->access->attach_dmabuf
|| !buffer->access->detach_dmabuf
|| !buffer->access->enqueue_dmabuf)
return -EPERM;
if (copy_from_user(&fd, user_fd, sizeof(fd)))
return -EFAULT;
priv = kzalloc(sizeof(*priv), GFP_KERNEL);
if (!priv)
return -ENOMEM;
spin_lock_init(&priv->lock);
priv->context = dma_fence_context_alloc(1);
dmabuf = dma_buf_get(fd);
if (IS_ERR(dmabuf)) {
err = PTR_ERR(dmabuf);
goto err_free_priv;
}
attach = dma_buf_attach(dmabuf, indio_dev->dev.parent);
if (IS_ERR(attach)) {
err = PTR_ERR(attach);
goto err_dmabuf_put;
}
err = iio_dma_resv_lock(dmabuf, nonblock);
if (err)
goto err_dmabuf_detach;
priv->dir = buffer->direction == IIO_BUFFER_DIRECTION_IN
? DMA_FROM_DEVICE : DMA_TO_DEVICE;
priv->sgt = dma_buf_map_attachment(attach, priv->dir);
if (IS_ERR(priv->sgt)) {
err = PTR_ERR(priv->sgt);
dev_err(&indio_dev->dev, "Unable to map attachment: %d\n", err);
goto err_resv_unlock;
}
kref_init(&priv->ref);
priv->buffer = buffer;
priv->attach = attach;
attach->importer_priv = priv;
priv->block = buffer->access->attach_dmabuf(buffer, attach);
if (IS_ERR(priv->block)) {
err = PTR_ERR(priv->block);
goto err_dmabuf_unmap_attachment;
}
dma_resv_unlock(dmabuf->resv);
mutex_lock(&buffer->dmabufs_mutex);
/*
* Check whether we already have an attachment for this driver/DMABUF
* combo. If we do, refuse to attach.
*/
list_for_each_entry(each, &buffer->dmabufs, entry) {
if (each->attach->dev == indio_dev->dev.parent
&& each->attach->dmabuf == dmabuf) {
/*
* We unlocked the reservation object, so going through
* the cleanup code would mean re-locking it first.
* At this stage it is simpler to free the attachment
* using iio_buffer_dma_put().
*/
mutex_unlock(&buffer->dmabufs_mutex);
iio_buffer_dmabuf_put(attach);
return -EBUSY;
}
}
/* Otherwise, add the new attachment to our dmabufs list. */
list_add(&priv->entry, &buffer->dmabufs);
mutex_unlock(&buffer->dmabufs_mutex);
return 0;
err_dmabuf_unmap_attachment:
dma_buf_unmap_attachment(attach, priv->sgt, priv->dir);
err_resv_unlock:
dma_resv_unlock(dmabuf->resv);
err_dmabuf_detach:
dma_buf_detach(dmabuf, attach);
err_dmabuf_put:
dma_buf_put(dmabuf);
err_free_priv:
kfree(priv);
return err;
}
static int iio_buffer_detach_dmabuf(struct iio_dev_buffer_pair *ib,
int __user *user_req, bool nonblock)
{
struct iio_buffer *buffer = ib->buffer;
struct iio_dev *indio_dev = ib->indio_dev;
struct iio_dmabuf_priv *priv;
struct dma_buf *dmabuf;
int dmabuf_fd, ret = -EPERM;
if (copy_from_user(&dmabuf_fd, user_req, sizeof(dmabuf_fd)))
return -EFAULT;
dmabuf = dma_buf_get(dmabuf_fd);
if (IS_ERR(dmabuf))
return PTR_ERR(dmabuf);
guard(mutex)(&buffer->dmabufs_mutex);
list_for_each_entry(priv, &buffer->dmabufs, entry) {
if (priv->attach->dev == indio_dev->dev.parent
&& priv->attach->dmabuf == dmabuf) {
list_del(&priv->entry);
/* Unref the reference from iio_buffer_attach_dmabuf() */
iio_buffer_dmabuf_put(priv->attach);
ret = 0;
break;
}
}
dma_buf_put(dmabuf);
return ret;
}
static const char *
iio_buffer_dma_fence_get_driver_name(struct dma_fence *fence)
{
return "iio";
}
static void iio_buffer_dma_fence_release(struct dma_fence *fence)
{
struct iio_dma_fence *iio_fence =
container_of(fence, struct iio_dma_fence, base);
kfree(iio_fence);
}
static const struct dma_fence_ops iio_buffer_dma_fence_ops = {
.get_driver_name = iio_buffer_dma_fence_get_driver_name,
.get_timeline_name = iio_buffer_dma_fence_get_driver_name,
.release = iio_buffer_dma_fence_release,
};
static int iio_buffer_enqueue_dmabuf(struct iio_dev_buffer_pair *ib,
struct iio_dmabuf __user *iio_dmabuf_req,
bool nonblock)
{
struct iio_buffer *buffer = ib->buffer;
struct iio_dmabuf iio_dmabuf;
struct dma_buf_attachment *attach;
struct iio_dmabuf_priv *priv;
struct iio_dma_fence *fence;
struct dma_buf *dmabuf;
unsigned long timeout;
bool cookie, cyclic, dma_to_ram;
long retl;
u32 seqno;
int ret;
if (copy_from_user(&iio_dmabuf, iio_dmabuf_req, sizeof(iio_dmabuf)))
return -EFAULT;
if (iio_dmabuf.flags & ~IIO_BUFFER_DMABUF_SUPPORTED_FLAGS)
return -EINVAL;
cyclic = iio_dmabuf.flags & IIO_BUFFER_DMABUF_CYCLIC;
/* Cyclic flag is only supported on output buffers */
if (cyclic && buffer->direction != IIO_BUFFER_DIRECTION_OUT)
return -EINVAL;
dmabuf = dma_buf_get(iio_dmabuf.fd);
if (IS_ERR(dmabuf))
return PTR_ERR(dmabuf);
if (!iio_dmabuf.bytes_used || iio_dmabuf.bytes_used > dmabuf->size) {
ret = -EINVAL;
goto err_dmabuf_put;
}
attach = iio_buffer_find_attachment(ib, dmabuf, nonblock);
if (IS_ERR(attach)) {
ret = PTR_ERR(attach);
goto err_dmabuf_put;
}
priv = attach->importer_priv;
fence = kmalloc(sizeof(*fence), GFP_KERNEL);
if (!fence) {
ret = -ENOMEM;
goto err_attachment_put;
}
fence->priv = priv;
seqno = atomic_add_return(1, &priv->seqno);
/*
* The transfers are guaranteed to be processed in the order they are
* enqueued, so we can use a simple incrementing sequence number for
* the dma_fence.
*/
dma_fence_init(&fence->base, &iio_buffer_dma_fence_ops,
&priv->lock, priv->context, seqno);
ret = iio_dma_resv_lock(dmabuf, nonblock);
if (ret)
goto err_fence_put;
timeout = nonblock ? 0 : msecs_to_jiffies(DMABUF_ENQUEUE_TIMEOUT_MS);
dma_to_ram = buffer->direction == IIO_BUFFER_DIRECTION_IN;
/* Make sure we don't have writers */
retl = dma_resv_wait_timeout(dmabuf->resv,
dma_resv_usage_rw(dma_to_ram),
true, timeout);
if (retl == 0)
retl = -EBUSY;
if (retl < 0) {
ret = (int)retl;
goto err_resv_unlock;
}
if (buffer->access->lock_queue)
buffer->access->lock_queue(buffer);
ret = dma_resv_reserve_fences(dmabuf->resv, 1);
if (ret)
goto err_queue_unlock;
dma_resv_add_fence(dmabuf->resv, &fence->base,
dma_to_ram ? DMA_RESV_USAGE_WRITE : DMA_RESV_USAGE_READ);
dma_resv_unlock(dmabuf->resv);
cookie = dma_fence_begin_signalling();
ret = buffer->access->enqueue_dmabuf(buffer, priv->block, &fence->base,
priv->sgt, iio_dmabuf.bytes_used,
cyclic);
if (ret) {
/*
* DMABUF enqueue failed, but we already added the fence.
* Signal the error through the fence completion mechanism.
*/
iio_buffer_signal_dmabuf_done(&fence->base, ret);
}
if (buffer->access->unlock_queue)
buffer->access->unlock_queue(buffer);
dma_fence_end_signalling(cookie);
dma_buf_put(dmabuf);
return ret;
err_queue_unlock:
if (buffer->access->unlock_queue)
buffer->access->unlock_queue(buffer);
err_resv_unlock:
dma_resv_unlock(dmabuf->resv);
err_fence_put:
dma_fence_put(&fence->base);
err_attachment_put:
iio_buffer_dmabuf_put(attach);
err_dmabuf_put:
dma_buf_put(dmabuf);
return ret;
}
static void iio_buffer_cleanup(struct work_struct *work)
{
struct iio_dma_fence *fence =
container_of(work, struct iio_dma_fence, work);
struct iio_dmabuf_priv *priv = fence->priv;
struct dma_buf_attachment *attach = priv->attach;
dma_fence_put(&fence->base);
iio_buffer_dmabuf_put(attach);
}
void iio_buffer_signal_dmabuf_done(struct dma_fence *fence, int ret)
{
struct iio_dma_fence *iio_fence =
container_of(fence, struct iio_dma_fence, base);
bool cookie = dma_fence_begin_signalling();
/*
* Get a reference to the fence, so that it's not freed as soon as
* it's signaled.
*/
dma_fence_get(fence);
fence->error = ret;
dma_fence_signal(fence);
dma_fence_end_signalling(cookie);
/*
* The fence will be unref'd in iio_buffer_cleanup.
* It can't be done here, as the unref functions might try to lock the
* resv object, which can deadlock.
*/
INIT_WORK(&iio_fence->work, iio_buffer_cleanup);
schedule_work(&iio_fence->work);
}
EXPORT_SYMBOL_GPL(iio_buffer_signal_dmabuf_done);
static long iio_buffer_chrdev_ioctl(struct file *filp,
unsigned int cmd, unsigned long arg)
{
struct iio_dev_buffer_pair *ib = filp->private_data;
void __user *_arg = (void __user *)arg;
bool nonblock = filp->f_flags & O_NONBLOCK;
switch (cmd) {
case IIO_BUFFER_DMABUF_ATTACH_IOCTL:
return iio_buffer_attach_dmabuf(ib, _arg, nonblock);
case IIO_BUFFER_DMABUF_DETACH_IOCTL:
return iio_buffer_detach_dmabuf(ib, _arg, nonblock);
case IIO_BUFFER_DMABUF_ENQUEUE_IOCTL:
return iio_buffer_enqueue_dmabuf(ib, _arg, nonblock);
default:
return -EINVAL;
}
}
static const struct file_operations iio_buffer_chrdev_fileops = {
.owner = THIS_MODULE,
.llseek = noop_llseek,
.read = iio_buffer_read,
.write = iio_buffer_write,
.unlocked_ioctl = iio_buffer_chrdev_ioctl,
.compat_ioctl = compat_ptr_ioctl,
.poll = iio_buffer_poll,
.release = iio_buffer_chrdev_release,
};
static long iio_device_buffer_getfd(struct iio_dev *indio_dev, unsigned long arg)
{
struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
int __user *ival = (int __user *)arg;
struct iio_dev_buffer_pair *ib;
struct iio_buffer *buffer;
int fd, idx, ret;
if (copy_from_user(&idx, ival, sizeof(idx)))
return -EFAULT;
if (idx >= iio_dev_opaque->attached_buffers_cnt)
return -ENODEV;
iio_device_get(indio_dev);
buffer = iio_dev_opaque->attached_buffers[idx];
if (test_and_set_bit(IIO_BUSY_BIT_POS, &buffer->flags)) {
ret = -EBUSY;
goto error_iio_dev_put;
}
ib = kzalloc(sizeof(*ib), GFP_KERNEL);
if (!ib) {
ret = -ENOMEM;
goto error_clear_busy_bit;
}
ib->indio_dev = indio_dev;
ib->buffer = buffer;
fd = anon_inode_getfd("iio:buffer", &iio_buffer_chrdev_fileops,
ib, O_RDWR | O_CLOEXEC);
if (fd < 0) {
ret = fd;
goto error_free_ib;
}
if (copy_to_user(ival, &fd, sizeof(fd))) {
/*
* "Leak" the fd, as there's not much we can do about this
* anyway. 'fd' might have been closed already, as
* anon_inode_getfd() called fd_install() on it, which made
* it reachable by userland.
*
* Instead of allowing a malicious user to play tricks with
* us, rely on the process exit path to do any necessary
* cleanup, as in releasing the file, if still needed.
*/
return -EFAULT;
}
return 0;
error_free_ib:
kfree(ib);
error_clear_busy_bit:
clear_bit(IIO_BUSY_BIT_POS, &buffer->flags);
error_iio_dev_put:
iio_device_put(indio_dev);
return ret;
}
static long iio_device_buffer_ioctl(struct iio_dev *indio_dev, struct file *filp,
unsigned int cmd, unsigned long arg)
{
switch (cmd) {
case IIO_BUFFER_GET_FD_IOCTL:
return iio_device_buffer_getfd(indio_dev, arg);
default:
return IIO_IOCTL_UNHANDLED;
}
}
static int iio_channel_validate_scan_type(struct device *dev, int ch,
const struct iio_scan_type *scan_type)
{
/* Verify that sample bits fit into storage */
if (scan_type->storagebits < scan_type->realbits + scan_type->shift) {
dev_err(dev,
"Channel %d storagebits (%d) < shifted realbits (%d + %d)\n",
ch, scan_type->storagebits,
scan_type->realbits,
scan_type->shift);
return -EINVAL;
}
return 0;
}
static int __iio_buffer_alloc_sysfs_and_mask(struct iio_buffer *buffer,
struct iio_dev *indio_dev,
int index)
{
struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
unsigned int masklength = iio_get_masklength(indio_dev);
struct iio_dev_attr *p;
const struct iio_dev_attr *id_attr;
struct attribute **attr;
int ret, i, attrn, scan_el_attrcount, buffer_attrcount;
const struct iio_chan_spec *channels;
buffer_attrcount = 0;
if (buffer->attrs) {
while (buffer->attrs[buffer_attrcount])
buffer_attrcount++;
}
buffer_attrcount += ARRAY_SIZE(iio_buffer_attrs);
scan_el_attrcount = 0;
INIT_LIST_HEAD(&buffer->buffer_attr_list);
channels = indio_dev->channels;
if (channels) {
/* new magic */
for (i = 0; i < indio_dev->num_channels; i++) {
const struct iio_scan_type *scan_type;
if (channels[i].scan_index < 0)
continue;
if (channels[i].has_ext_scan_type) {
int j;
/*
* get_current_scan_type is required when using
* extended scan types.
*/
if (!indio_dev->info->get_current_scan_type) {
ret = -EINVAL;
goto error_cleanup_dynamic;
}
for (j = 0; j < channels[i].num_ext_scan_type; j++) {
scan_type = &channels[i].ext_scan_type[j];
ret = iio_channel_validate_scan_type(
&indio_dev->dev, i, scan_type);
if (ret)
goto error_cleanup_dynamic;
}
} else {
scan_type = &channels[i].scan_type;
ret = iio_channel_validate_scan_type(
&indio_dev->dev, i, scan_type);
if (ret)
goto error_cleanup_dynamic;
}
ret = iio_buffer_add_channel_sysfs(indio_dev, buffer,
&channels[i]);
if (ret < 0)
goto error_cleanup_dynamic;
scan_el_attrcount += ret;
if (channels[i].type == IIO_TIMESTAMP)
iio_dev_opaque->scan_index_timestamp =
channels[i].scan_index;
}
if (masklength && !buffer->scan_mask) {
buffer->scan_mask = bitmap_zalloc(masklength,
GFP_KERNEL);
if (!buffer->scan_mask) {
ret = -ENOMEM;
goto error_cleanup_dynamic;
}
}
}
attrn = buffer_attrcount + scan_el_attrcount;
attr = kcalloc(attrn + 1, sizeof(*attr), GFP_KERNEL);
if (!attr) {
ret = -ENOMEM;
goto error_free_scan_mask;
}
memcpy(attr, iio_buffer_attrs, sizeof(iio_buffer_attrs));
if (!buffer->access->set_length)
attr[0] = &dev_attr_length_ro.attr;
if (buffer->access->flags & INDIO_BUFFER_FLAG_FIXED_WATERMARK)
attr[2] = &dev_attr_watermark_ro.attr;
if (buffer->attrs)
for (i = 0, id_attr = buffer->attrs[i];
(id_attr = buffer->attrs[i]); i++)
attr[ARRAY_SIZE(iio_buffer_attrs) + i] =
(struct attribute *)&id_attr->dev_attr.attr;
buffer->buffer_group.attrs = attr;
for (i = 0; i < buffer_attrcount; i++) {
struct attribute *wrapped;
wrapped = iio_buffer_wrap_attr(buffer, attr[i]);
if (!wrapped) {
ret = -ENOMEM;
goto error_free_buffer_attrs;
}
attr[i] = wrapped;
}
attrn = 0;
list_for_each_entry(p, &buffer->buffer_attr_list, l)
attr[attrn++] = &p->dev_attr.attr;
buffer->buffer_group.name = kasprintf(GFP_KERNEL, "buffer%d", index);
if (!buffer->buffer_group.name) {
ret = -ENOMEM;
goto error_free_buffer_attrs;
}
ret = iio_device_register_sysfs_group(indio_dev, &buffer->buffer_group);
if (ret)
goto error_free_buffer_attr_group_name;
/* we only need to register the legacy groups for the first buffer */
if (index > 0)
return 0;
ret = iio_buffer_register_legacy_sysfs_groups(indio_dev, attr,
buffer_attrcount,
scan_el_attrcount);
if (ret)
goto error_free_buffer_attr_group_name;
return 0;
error_free_buffer_attr_group_name:
kfree(buffer->buffer_group.name);
error_free_buffer_attrs:
kfree(buffer->buffer_group.attrs);
error_free_scan_mask:
bitmap_free(buffer->scan_mask);
error_cleanup_dynamic:
iio_free_chan_devattr_list(&buffer->buffer_attr_list);
return ret;
}
static void __iio_buffer_free_sysfs_and_mask(struct iio_buffer *buffer,
struct iio_dev *indio_dev,
int index)
{
if (index == 0)
iio_buffer_unregister_legacy_sysfs_groups(indio_dev);
bitmap_free(buffer->scan_mask);
kfree(buffer->buffer_group.name);
kfree(buffer->buffer_group.attrs);
iio_free_chan_devattr_list(&buffer->buffer_attr_list);
}
int iio_buffers_alloc_sysfs_and_mask(struct iio_dev *indio_dev)
{
struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
const struct iio_chan_spec *channels;
struct iio_buffer *buffer;
int ret, i, idx;
size_t sz;
channels = indio_dev->channels;
if (channels) {
int ml = 0;
for (i = 0; i < indio_dev->num_channels; i++)
ml = max(ml, channels[i].scan_index + 1);
ACCESS_PRIVATE(indio_dev, masklength) = ml;
}
if (!iio_dev_opaque->attached_buffers_cnt)
return 0;
for (idx = 0; idx < iio_dev_opaque->attached_buffers_cnt; idx++) {
buffer = iio_dev_opaque->attached_buffers[idx];
ret = __iio_buffer_alloc_sysfs_and_mask(buffer, indio_dev, idx);
if (ret)
goto error_unwind_sysfs_and_mask;
}
sz = sizeof(*iio_dev_opaque->buffer_ioctl_handler);
iio_dev_opaque->buffer_ioctl_handler = kzalloc(sz, GFP_KERNEL);
if (!iio_dev_opaque->buffer_ioctl_handler) {
ret = -ENOMEM;
goto error_unwind_sysfs_and_mask;
}
iio_dev_opaque->buffer_ioctl_handler->ioctl = iio_device_buffer_ioctl;
iio_device_ioctl_handler_register(indio_dev,
iio_dev_opaque->buffer_ioctl_handler);
return 0;
error_unwind_sysfs_and_mask:
while (idx--) {
buffer = iio_dev_opaque->attached_buffers[idx];
__iio_buffer_free_sysfs_and_mask(buffer, indio_dev, idx);
}
return ret;
}
void iio_buffers_free_sysfs_and_mask(struct iio_dev *indio_dev)
{
struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
struct iio_buffer *buffer;
int i;
if (!iio_dev_opaque->attached_buffers_cnt)
return;
iio_device_ioctl_handler_unregister(iio_dev_opaque->buffer_ioctl_handler);
kfree(iio_dev_opaque->buffer_ioctl_handler);
for (i = iio_dev_opaque->attached_buffers_cnt - 1; i >= 0; i--) {
buffer = iio_dev_opaque->attached_buffers[i];
__iio_buffer_free_sysfs_and_mask(buffer, indio_dev, i);
}
}
/**
* iio_validate_scan_mask_onehot() - Validates that exactly one channel is selected
* @indio_dev: the iio device
* @mask: scan mask to be checked
*
* Return true if exactly one bit is set in the scan mask, false otherwise. It
* can be used for devices where only one channel can be active for sampling at
* a time.
*/
bool iio_validate_scan_mask_onehot(struct iio_dev *indio_dev,
const unsigned long *mask)
{
return bitmap_weight(mask, iio_get_masklength(indio_dev)) == 1;
}
EXPORT_SYMBOL_GPL(iio_validate_scan_mask_onehot);
static const void *iio_demux(struct iio_buffer *buffer,
const void *datain)
{
struct iio_demux_table *t;
if (list_empty(&buffer->demux_list))
return datain;
list_for_each_entry(t, &buffer->demux_list, l)
memcpy(buffer->demux_bounce + t->to,
datain + t->from, t->length);
return buffer->demux_bounce;
}
static int iio_push_to_buffer(struct iio_buffer *buffer, const void *data)
{
const void *dataout = iio_demux(buffer, data);
int ret;
ret = buffer->access->store_to(buffer, dataout);
if (ret)
return ret;
/*
* We can't just test for watermark to decide if we wake the poll queue
* because read may request less samples than the watermark.
*/
wake_up_interruptible_poll(&buffer->pollq, EPOLLIN | EPOLLRDNORM);
return 0;
}
/**
* iio_push_to_buffers() - push to a registered buffer.
* @indio_dev: iio_dev structure for device.
* @data: Full scan.
*/
int iio_push_to_buffers(struct iio_dev *indio_dev, const void *data)
{
struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
int ret;
struct iio_buffer *buf;
list_for_each_entry(buf, &iio_dev_opaque->buffer_list, buffer_list) {
ret = iio_push_to_buffer(buf, data);
if (ret < 0)
return ret;
}
return 0;
}
EXPORT_SYMBOL_GPL(iio_push_to_buffers);
/**
* iio_push_to_buffers_with_ts_unaligned() - push to registered buffer,
* no alignment or space requirements.
* @indio_dev: iio_dev structure for device.
* @data: channel data excluding the timestamp.
* @data_sz: size of data.
* @timestamp: timestamp for the sample data.
*
* This special variant of iio_push_to_buffers_with_timestamp() does
* not require space for the timestamp, or 8 byte alignment of data.
* It does however require an allocation on first call and additional
* copies on all calls, so should be avoided if possible.
*/
int iio_push_to_buffers_with_ts_unaligned(struct iio_dev *indio_dev,
const void *data,
size_t data_sz,
int64_t timestamp)
{
struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
/*
* Conservative estimate - we can always safely copy the minimum
* of either the data provided or the length of the destination buffer.
* This relaxed limit allows the calling drivers to be lax about
* tracking the size of the data they are pushing, at the cost of
* unnecessary copying of padding.
*/
data_sz = min_t(size_t, indio_dev->scan_bytes, data_sz);
if (iio_dev_opaque->bounce_buffer_size != indio_dev->scan_bytes) {
void *bb;
bb = devm_krealloc(&indio_dev->dev,
iio_dev_opaque->bounce_buffer,
indio_dev->scan_bytes, GFP_KERNEL);
if (!bb)
return -ENOMEM;
iio_dev_opaque->bounce_buffer = bb;
iio_dev_opaque->bounce_buffer_size = indio_dev->scan_bytes;
}
memcpy(iio_dev_opaque->bounce_buffer, data, data_sz);
return iio_push_to_buffers_with_timestamp(indio_dev,
iio_dev_opaque->bounce_buffer,
timestamp);
}
EXPORT_SYMBOL_GPL(iio_push_to_buffers_with_ts_unaligned);
/**
* iio_buffer_release() - Free a buffer's resources
* @ref: Pointer to the kref embedded in the iio_buffer struct
*
* This function is called when the last reference to the buffer has been
* dropped. It will typically free all resources allocated by the buffer. Do not
* call this function manually, always use iio_buffer_put() when done using a
* buffer.
*/
static void iio_buffer_release(struct kref *ref)
{
struct iio_buffer *buffer = container_of(ref, struct iio_buffer, ref);
mutex_destroy(&buffer->dmabufs_mutex);
buffer->access->release(buffer);
}
/**
* iio_buffer_get() - Grab a reference to the buffer
* @buffer: The buffer to grab a reference for, may be NULL
*
* Returns the pointer to the buffer that was passed into the function.
*/
struct iio_buffer *iio_buffer_get(struct iio_buffer *buffer)
{
if (buffer)
kref_get(&buffer->ref);
return buffer;
}
EXPORT_SYMBOL_GPL(iio_buffer_get);
/**
* iio_buffer_put() - Release the reference to the buffer
* @buffer: The buffer to release the reference for, may be NULL
*/
void iio_buffer_put(struct iio_buffer *buffer)
{
if (buffer)
kref_put(&buffer->ref, iio_buffer_release);
}
EXPORT_SYMBOL_GPL(iio_buffer_put);
/**
* iio_device_attach_buffer - Attach a buffer to a IIO device
* @indio_dev: The device the buffer should be attached to
* @buffer: The buffer to attach to the device
*
* Return 0 if successful, negative if error.
*
* This function attaches a buffer to a IIO device. The buffer stays attached to
* the device until the device is freed. For legacy reasons, the first attached
* buffer will also be assigned to 'indio_dev->buffer'.
* The array allocated here, will be free'd via the iio_device_detach_buffers()
* call which is handled by the iio_device_free().
*/
int iio_device_attach_buffer(struct iio_dev *indio_dev,
struct iio_buffer *buffer)
{
struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
struct iio_buffer **new, **old = iio_dev_opaque->attached_buffers;
unsigned int cnt = iio_dev_opaque->attached_buffers_cnt;
cnt++;
new = krealloc(old, sizeof(*new) * cnt, GFP_KERNEL);
if (!new)
return -ENOMEM;
iio_dev_opaque->attached_buffers = new;
buffer = iio_buffer_get(buffer);
/* first buffer is legacy; attach it to the IIO device directly */
if (!indio_dev->buffer)
indio_dev->buffer = buffer;
iio_dev_opaque->attached_buffers[cnt - 1] = buffer;
iio_dev_opaque->attached_buffers_cnt = cnt;
return 0;
}
EXPORT_SYMBOL_GPL(iio_device_attach_buffer);
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