linux/drivers/iio/industrialio-buffer.c
Nuno Sá 19ef7b70ca iio: buffer: Fix demux update
When updating the buffer demux, we will skip a scan element from the
device in the case `in_ind != out_ind` and we enter the while loop.
in_ind should only be refreshed with `find_next_bit()` in the end of the
loop.

Note, to cause problems we need a situation where we are skippig over
an element (channel not enabled) that happens to not have the same size
as the next element.   Whilst this is a possible situation we haven't
actually identified any cases in mainline where it happens as most drivers
have consistent channel storage sizes with the exception of the timestamp
which is the last element and hence never skipped over.

Fixes: 5ada4ea9be ("staging:iio: add demux optionally to path from device to buffer")
Signed-off-by: Nuno Sá <nuno.sa@analog.com>
Link: https://lore.kernel.org/r/20201112144323.28887-1-nuno.sa@analog.com
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
2020-12-03 19:32:44 +00:00

1510 lines
38 KiB
C

// 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/kernel.h>
#include <linux/export.h>
#include <linux/device.h>
#include <linux/fs.h>
#include <linux/cdev.h>
#include <linux/slab.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>
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_outer() - 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
**/
ssize_t iio_buffer_read_outer(struct file *filp, char __user *buf,
size_t n, loff_t *f_ps)
{
struct iio_dev *indio_dev = filp->private_data;
struct iio_buffer *rb = indio_dev->buffer;
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;
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;
}
/**
* 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
*/
__poll_t iio_buffer_poll(struct file *filp,
struct poll_table_struct *wait)
{
struct iio_dev *indio_dev = filp->private_data;
struct iio_buffer *rb = indio_dev->buffer;
if (!indio_dev->info || rb == NULL)
return 0;
poll_wait(filp, &rb->pollq, wait);
if (iio_buffer_ready(indio_dev, rb, rb->watermark, 0))
return EPOLLIN | EPOLLRDNORM;
return 0;
}
/**
* 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_buffer *buffer = indio_dev->buffer;
if (!buffer)
return;
wake_up(&buffer->pollq);
}
void iio_buffer_init(struct iio_buffer *buffer)
{
INIT_LIST_HEAD(&buffer->demux_list);
INIT_LIST_HEAD(&buffer->buffer_list);
init_waitqueue_head(&buffer->pollq);
kref_init(&buffer->ref);
if (!buffer->watermark)
buffer->watermark = 1;
}
EXPORT_SYMBOL(iio_buffer_init);
static ssize_t iio_show_scan_index(struct device *dev,
struct device_attribute *attr,
char *buf)
{
return sprintf(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_attr *this_attr = to_iio_dev_attr(attr);
u8 type = this_attr->c->scan_type.endianness;
if (type == IIO_CPU) {
#ifdef __LITTLE_ENDIAN
type = IIO_LE;
#else
type = IIO_BE;
#endif
}
if (this_attr->c->scan_type.repeat > 1)
return sprintf(buf, "%s:%c%d/%dX%d>>%u\n",
iio_endian_prefix[type],
this_attr->c->scan_type.sign,
this_attr->c->scan_type.realbits,
this_attr->c->scan_type.storagebits,
this_attr->c->scan_type.repeat,
this_attr->c->scan_type.shift);
else
return sprintf(buf, "%s:%c%d/%d>>%u\n",
iio_endian_prefix[type],
this_attr->c->scan_type.sign,
this_attr->c->scan_type.realbits,
this_attr->c->scan_type.storagebits,
this_attr->c->scan_type.shift);
}
static ssize_t iio_scan_el_show(struct device *dev,
struct device_attribute *attr,
char *buf)
{
int ret;
struct iio_dev *indio_dev = dev_to_iio_dev(dev);
struct iio_buffer *buffer = indio_dev->buffer;
/* Ensure ret is 0 or 1. */
ret = !!test_bit(to_iio_dev_attr(attr)->address,
buffer->scan_mask);
return sprintf(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;
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)
{
const unsigned long *mask;
unsigned long *trialmask;
trialmask = bitmap_zalloc(indio_dev->masklength, GFP_KERNEL);
if (trialmask == NULL)
return -ENOMEM;
if (!indio_dev->masklength) {
WARN(1, "Trying to set scanmask prior to registering buffer\n");
goto err_invalid_mask;
}
bitmap_copy(trialmask, buffer->scan_mask, indio_dev->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,
indio_dev->masklength,
trialmask, false);
if (!mask)
goto err_invalid_mask;
}
bitmap_copy(buffer->scan_mask, trialmask, indio_dev->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 > indio_dev->masklength)
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_buffer *buffer = indio_dev->buffer;
struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
ret = strtobool(buf, &state);
if (ret < 0)
return ret;
mutex_lock(&indio_dev->mlock);
if (iio_buffer_is_active(buffer)) {
ret = -EBUSY;
goto error_ret;
}
ret = iio_scan_mask_query(indio_dev, buffer, this_attr->address);
if (ret < 0)
goto error_ret;
if (!state && ret) {
ret = iio_scan_mask_clear(buffer, this_attr->address);
if (ret)
goto error_ret;
} else if (state && !ret) {
ret = iio_scan_mask_set(indio_dev, buffer, this_attr->address);
if (ret)
goto error_ret;
}
error_ret:
mutex_unlock(&indio_dev->mlock);
return ret < 0 ? ret : len;
}
static ssize_t iio_scan_el_ts_show(struct device *dev,
struct device_attribute *attr,
char *buf)
{
struct iio_dev *indio_dev = dev_to_iio_dev(dev);
struct iio_buffer *buffer = indio_dev->buffer;
return sprintf(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_buffer *buffer = indio_dev->buffer;
bool state;
ret = strtobool(buf, &state);
if (ret < 0)
return ret;
mutex_lock(&indio_dev->mlock);
if (iio_buffer_is_active(buffer)) {
ret = -EBUSY;
goto error_ret;
}
buffer->scan_timestamp = state;
error_ret:
mutex_unlock(&indio_dev->mlock);
return ret ? ret : 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->scan_el_dev_attr_list);
if (ret)
return ret;
attrcount++;
ret = __iio_add_chan_devattr("type",
chan,
&iio_show_fixed_type,
NULL,
0,
0,
&indio_dev->dev,
&buffer->scan_el_dev_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,
0,
&indio_dev->dev,
&buffer->scan_el_dev_attr_list);
else
ret = __iio_add_chan_devattr("en",
chan,
&iio_scan_el_ts_show,
&iio_scan_el_ts_store,
chan->scan_index,
0,
&indio_dev->dev,
&buffer->scan_el_dev_attr_list);
if (ret)
return ret;
attrcount++;
ret = attrcount;
return ret;
}
static ssize_t iio_buffer_read_length(struct device *dev,
struct device_attribute *attr,
char *buf)
{
struct iio_dev *indio_dev = dev_to_iio_dev(dev);
struct iio_buffer *buffer = indio_dev->buffer;
return sprintf(buf, "%d\n", buffer->length);
}
static ssize_t iio_buffer_write_length(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_buffer *buffer = indio_dev->buffer;
unsigned int val;
int ret;
ret = kstrtouint(buf, 10, &val);
if (ret)
return ret;
if (val == buffer->length)
return len;
mutex_lock(&indio_dev->mlock);
if (iio_buffer_is_active(buffer)) {
ret = -EBUSY;
} else {
buffer->access->set_length(buffer, val);
ret = 0;
}
if (ret)
goto out;
if (buffer->length && buffer->length < buffer->watermark)
buffer->watermark = buffer->length;
out:
mutex_unlock(&indio_dev->mlock);
return ret ? ret : len;
}
static ssize_t iio_buffer_show_enable(struct device *dev,
struct device_attribute *attr,
char *buf)
{
struct iio_dev *indio_dev = dev_to_iio_dev(dev);
struct iio_buffer *buffer = indio_dev->buffer;
return sprintf(buf, "%d\n", iio_buffer_is_active(buffer));
}
static unsigned int iio_storage_bytes_for_si(struct iio_dev *indio_dev,
unsigned int scan_index)
{
const struct iio_chan_spec *ch;
unsigned int bytes;
ch = iio_find_channel_from_si(indio_dev, scan_index);
bytes = ch->scan_type.storagebits / 8;
if (ch->scan_type.repeat > 1)
bytes *= ch->scan_type.repeat;
return bytes;
}
static unsigned int iio_storage_bytes_for_timestamp(struct iio_dev *indio_dev)
{
return iio_storage_bytes_for_si(indio_dev,
indio_dev->scan_index_timestamp);
}
static int iio_compute_scan_bytes(struct iio_dev *indio_dev,
const unsigned long *mask, bool timestamp)
{
unsigned bytes = 0;
int length, i, largest = 0;
/* How much space will the demuxed element take? */
for_each_set_bit(i, mask,
indio_dev->masklength) {
length = iio_storage_bytes_for_si(indio_dev, i);
bytes = ALIGN(bytes, length);
bytes += length;
largest = max(largest, length);
}
if (timestamp) {
length = iio_storage_bytes_for_timestamp(indio_dev);
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 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, indio_dev->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(indio_dev->masklength, GFP_KERNEL);
if (compound_mask == NULL)
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,
indio_dev->masklength);
scan_timestamp |= buffer->scan_timestamp;
}
if (insert_buffer) {
bitmap_or(compound_mask, compound_mask,
insert_buffer->scan_mask, indio_dev->masklength);
scan_timestamp |= insert_buffer->scan_timestamp;
}
if (indio_dev->available_scan_masks) {
scan_mask = iio_scan_mask_match(indio_dev->available_scan_masks,
indio_dev->masklength,
compound_mask,
strict_scanmask);
bitmap_free(compound_mask);
if (scan_mask == NULL)
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 from;
unsigned to;
unsigned 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 == NULL)
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)
{
int ret, in_ind = -1, out_ind, length;
unsigned 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,
indio_dev->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,
indio_dev->masklength) {
in_ind = find_next_bit(indio_dev->active_scan_mask,
indio_dev->masklength,
in_ind + 1);
while (in_ind != out_ind) {
length = iio_storage_bytes_for_si(indio_dev, in_ind);
/* Make sure we are aligned */
in_loc = roundup(in_loc, length) + length;
in_ind = find_next_bit(indio_dev->active_scan_mask,
indio_dev->masklength,
in_ind + 1);
}
length = iio_storage_bytes_for_si(indio_dev, in_ind);
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) {
length = iio_storage_bytes_for_timestamp(indio_dev);
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;
}
buffer->demux_bounce = kzalloc(out_loc, GFP_KERNEL);
if (buffer->demux_bounce == NULL) {
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;
int ret;
indio_dev->active_scan_mask = config->scan_mask;
indio_dev->scan_timestamp = config->scan_timestamp;
indio_dev->scan_bytes = config->scan_bytes;
indio_dev->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)
goto err_disable_buffers;
}
if (indio_dev->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 (indio_dev->currentmode == INDIO_BUFFER_TRIGGERED) {
iio_trigger_detach_poll_func(indio_dev->trig,
indio_dev->pollfunc);
}
err_disable_buffers:
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:
indio_dev->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 (indio_dev->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;
indio_dev->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)
{
int ret;
if (insert_buffer == remove_buffer)
return 0;
mutex_lock(&indio_dev->info_exist_lock);
mutex_lock(&indio_dev->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) {
ret = 0;
goto out_unlock;
}
if (indio_dev->info == NULL) {
ret = -ENODEV;
goto out_unlock;
}
ret = __iio_update_buffers(indio_dev, insert_buffer, remove_buffer);
out_unlock:
mutex_unlock(&indio_dev->mlock);
mutex_unlock(&indio_dev->info_exist_lock);
return ret;
}
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 iio_buffer_store_enable(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_buffer *buffer = indio_dev->buffer;
bool inlist;
ret = strtobool(buf, &requested_state);
if (ret < 0)
return ret;
mutex_lock(&indio_dev->mlock);
/* Find out if it is in the list */
inlist = iio_buffer_is_active(buffer);
/* Already in desired state */
if (inlist == requested_state)
goto done;
if (requested_state)
ret = __iio_update_buffers(indio_dev, buffer, NULL);
else
ret = __iio_update_buffers(indio_dev, NULL, buffer);
done:
mutex_unlock(&indio_dev->mlock);
return (ret < 0) ? ret : len;
}
static const char * const iio_scan_elements_group_name = "scan_elements";
static ssize_t iio_buffer_show_watermark(struct device *dev,
struct device_attribute *attr,
char *buf)
{
struct iio_dev *indio_dev = dev_to_iio_dev(dev);
struct iio_buffer *buffer = indio_dev->buffer;
return sprintf(buf, "%u\n", buffer->watermark);
}
static ssize_t iio_buffer_store_watermark(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_buffer *buffer = indio_dev->buffer;
unsigned int val;
int ret;
ret = kstrtouint(buf, 10, &val);
if (ret)
return ret;
if (!val)
return -EINVAL;
mutex_lock(&indio_dev->mlock);
if (val > buffer->length) {
ret = -EINVAL;
goto out;
}
if (iio_buffer_is_active(buffer)) {
ret = -EBUSY;
goto out;
}
buffer->watermark = val;
out:
mutex_unlock(&indio_dev->mlock);
return ret ? ret : len;
}
static ssize_t iio_dma_show_data_available(struct device *dev,
struct device_attribute *attr,
char *buf)
{
struct iio_dev *indio_dev = dev_to_iio_dev(dev);
struct iio_buffer *buffer = indio_dev->buffer;
return sprintf(buf, "%zu\n", iio_buffer_data_available(buffer));
}
static DEVICE_ATTR(length, S_IRUGO | S_IWUSR, iio_buffer_read_length,
iio_buffer_write_length);
static struct device_attribute dev_attr_length_ro = __ATTR(length,
S_IRUGO, iio_buffer_read_length, NULL);
static DEVICE_ATTR(enable, S_IRUGO | S_IWUSR,
iio_buffer_show_enable, iio_buffer_store_enable);
static DEVICE_ATTR(watermark, S_IRUGO | S_IWUSR,
iio_buffer_show_watermark, iio_buffer_store_watermark);
static struct device_attribute dev_attr_watermark_ro = __ATTR(watermark,
S_IRUGO, iio_buffer_show_watermark, NULL);
static DEVICE_ATTR(data_available, S_IRUGO,
iio_dma_show_data_available, NULL);
static struct attribute *iio_buffer_attrs[] = {
&dev_attr_length.attr,
&dev_attr_enable.attr,
&dev_attr_watermark.attr,
&dev_attr_data_available.attr,
};
static int __iio_buffer_alloc_sysfs_and_mask(struct iio_buffer *buffer,
struct iio_dev *indio_dev)
{
struct iio_dev_attr *p;
struct attribute **attr;
int ret, i, attrn, attrcount;
const struct iio_chan_spec *channels;
attrcount = 0;
if (buffer->attrs) {
while (buffer->attrs[attrcount] != NULL)
attrcount++;
}
attr = kcalloc(attrcount + ARRAY_SIZE(iio_buffer_attrs) + 1,
sizeof(struct attribute *), GFP_KERNEL);
if (!attr)
return -ENOMEM;
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)
memcpy(&attr[ARRAY_SIZE(iio_buffer_attrs)], buffer->attrs,
sizeof(struct attribute *) * attrcount);
attr[attrcount + ARRAY_SIZE(iio_buffer_attrs)] = NULL;
buffer->buffer_group.name = "buffer";
buffer->buffer_group.attrs = attr;
indio_dev->groups[indio_dev->groupcounter++] = &buffer->buffer_group;
attrcount = 0;
INIT_LIST_HEAD(&buffer->scan_el_dev_attr_list);
channels = indio_dev->channels;
if (channels) {
/* new magic */
for (i = 0; i < indio_dev->num_channels; i++) {
if (channels[i].scan_index < 0)
continue;
ret = iio_buffer_add_channel_sysfs(indio_dev, buffer,
&channels[i]);
if (ret < 0)
goto error_cleanup_dynamic;
attrcount += ret;
if (channels[i].type == IIO_TIMESTAMP)
indio_dev->scan_index_timestamp =
channels[i].scan_index;
}
if (indio_dev->masklength && buffer->scan_mask == NULL) {
buffer->scan_mask = bitmap_zalloc(indio_dev->masklength,
GFP_KERNEL);
if (buffer->scan_mask == NULL) {
ret = -ENOMEM;
goto error_cleanup_dynamic;
}
}
}
buffer->scan_el_group.name = iio_scan_elements_group_name;
buffer->scan_el_group.attrs = kcalloc(attrcount + 1,
sizeof(buffer->scan_el_group.attrs[0]),
GFP_KERNEL);
if (buffer->scan_el_group.attrs == NULL) {
ret = -ENOMEM;
goto error_free_scan_mask;
}
attrn = 0;
list_for_each_entry(p, &buffer->scan_el_dev_attr_list, l)
buffer->scan_el_group.attrs[attrn++] = &p->dev_attr.attr;
indio_dev->groups[indio_dev->groupcounter++] = &buffer->scan_el_group;
return 0;
error_free_scan_mask:
bitmap_free(buffer->scan_mask);
error_cleanup_dynamic:
iio_free_chan_devattr_list(&buffer->scan_el_dev_attr_list);
kfree(buffer->buffer_group.attrs);
return ret;
}
int iio_buffer_alloc_sysfs_and_mask(struct iio_dev *indio_dev)
{
struct iio_buffer *buffer = indio_dev->buffer;
const struct iio_chan_spec *channels;
int i;
channels = indio_dev->channels;
if (channels) {
int ml = indio_dev->masklength;
for (i = 0; i < indio_dev->num_channels; i++)
ml = max(ml, channels[i].scan_index + 1);
indio_dev->masklength = ml;
}
if (!buffer)
return 0;
return __iio_buffer_alloc_sysfs_and_mask(buffer, indio_dev);
}
static void __iio_buffer_free_sysfs_and_mask(struct iio_buffer *buffer)
{
bitmap_free(buffer->scan_mask);
kfree(buffer->buffer_group.attrs);
kfree(buffer->scan_el_group.attrs);
iio_free_chan_devattr_list(&buffer->scan_el_dev_attr_list);
}
void iio_buffer_free_sysfs_and_mask(struct iio_dev *indio_dev)
{
struct iio_buffer *buffer = indio_dev->buffer;
if (!buffer)
return;
__iio_buffer_free_sysfs_and_mask(buffer);
}
/**
* 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, indio_dev->masklength) == 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_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);
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
*
* This function attaches a buffer to a IIO device. The buffer stays attached to
* the device until the device is freed. The function should only be called at
* most once per device.
*/
void iio_device_attach_buffer(struct iio_dev *indio_dev,
struct iio_buffer *buffer)
{
indio_dev->buffer = iio_buffer_get(buffer);
}
EXPORT_SYMBOL_GPL(iio_device_attach_buffer);