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local.c
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/*
* libiio - Library for interfacing industrial I/O (IIO) devices
*
* Copyright (C) 2014 Analog Devices, Inc.
* Author: Paul Cercueil <[email protected]>
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* */
#include "debug.h"
#include "iio-private.h"
#include <dirent.h>
#include <errno.h>
#include <limits.h>
#include <poll.h>
#include <stdbool.h>
#include <stddef.h>
#include <stdio.h>
#include <string.h>
#include <sys/eventfd.h>
#include <sys/ioctl.h>
#include <sys/mman.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#include <string.h>
#include <sys/utsname.h>
#include <time.h>
#include <unistd.h>
#include <fcntl.h>
#ifdef WITH_LOCAL_CONFIG
#include <ini.h>
#endif
#define DEFAULT_TIMEOUT_MS 1000
#define NB_BLOCKS 4
#define BLOCK_ALLOC_IOCTL _IOWR('i', 0xa0, struct block_alloc_req)
#define BLOCK_FREE_IOCTL _IO('i', 0xa1)
#define BLOCK_QUERY_IOCTL _IOWR('i', 0xa2, struct block)
#define BLOCK_ENQUEUE_IOCTL _IOWR('i', 0xa3, struct block)
#define BLOCK_DEQUEUE_IOCTL _IOWR('i', 0xa4, struct block)
#define BLOCK_FLAG_CYCLIC BIT(1)
/* Forward declarations */
static ssize_t local_read_dev_attr(const struct iio_device *dev,
const char *attr, char *dst, size_t len, enum iio_attr_type type);
static ssize_t local_read_chn_attr(const struct iio_channel *chn,
const char *attr, char *dst, size_t len);
static ssize_t local_write_dev_attr(const struct iio_device *dev,
const char *attr, const char *src, size_t len, enum iio_attr_type type);
static ssize_t local_write_chn_attr(const struct iio_channel *chn,
const char *attr, const char *src, size_t len);
struct block_alloc_req {
uint32_t type,
size,
count,
id;
};
struct block {
uint32_t id,
size,
bytes_used,
type,
flags,
offset;
uint64_t timestamp;
};
struct iio_context_pdata {
unsigned int rw_timeout_ms;
};
struct iio_device_pdata {
int fd;
bool blocking;
unsigned int samples_count;
unsigned int max_nb_blocks;
unsigned int allocated_nb_blocks;
struct block *blocks;
void **addrs;
int last_dequeued;
bool is_high_speed, cyclic, cyclic_buffer_enqueued, buffer_enabled;
int cancel_fd;
};
struct iio_channel_pdata {
char *enable_fn;
struct iio_channel_attr *protected_attrs;
unsigned int nb_protected_attrs;
};
static const char * const device_attrs_blacklist[] = {
"dev",
"uevent",
};
static const char * const buffer_attrs_reserved[] = {
"length",
"enable",
};
static int ioctl_nointr(int fd, unsigned long request, void *data)
{
int ret;
do {
ret = ioctl(fd, request, data);
} while (ret == -1 && errno == EINTR);
return ret;
}
static void local_free_channel_pdata(struct iio_channel *chn)
{
if (chn->pdata) {
free(chn->pdata->enable_fn);
free(chn->pdata);
}
}
static void local_free_pdata(struct iio_device *device)
{
unsigned int i;
for (i = 0; i < device->nb_channels; i++)
local_free_channel_pdata(device->channels[i]);
if (device->pdata) {
free(device->pdata->blocks);
free(device->pdata->addrs);
free(device->pdata);
}
}
static void local_shutdown(struct iio_context *ctx)
{
/* Free the backend data stored in every device structure */
unsigned int i;
for (i = 0; i < ctx->nb_devices; i++) {
struct iio_device *dev = ctx->devices[i];
iio_device_close(dev);
local_free_pdata(dev);
}
free(ctx->pdata);
}
/** Shrinks the first nb characters of a string
* e.g. strcut("foobar", 4) replaces the content with "ar". */
static void strcut(char *str, int nb)
{
char *ptr = str + nb;
while (*ptr)
*str++ = *ptr++;
*str = 0;
}
static int set_channel_name(struct iio_channel *chn)
{
struct iio_channel_pdata *pdata = chn->pdata;
size_t prefix_len = 0;
const char *attr0;
const char *ptr;
unsigned int i;
if (chn->nb_attrs + pdata->nb_protected_attrs < 2)
return 0;
if (chn->nb_attrs)
attr0 = ptr = chn->attrs[0].name;
else
attr0 = ptr = pdata->protected_attrs[0].name;
while (true) {
bool can_fix = true;
size_t len;
ptr = strchr(ptr, '_');
if (!ptr)
break;
len = ptr - attr0 + 1;
for (i = 1; can_fix && i < chn->nb_attrs; i++)
can_fix = !strncmp(attr0, chn->attrs[i].name, len);
for (i = !chn->nb_attrs;
can_fix && i < pdata->nb_protected_attrs; i++) {
can_fix = !strncmp(attr0,
pdata->protected_attrs[i].name, len);
}
if (!can_fix)
break;
prefix_len = len;
ptr = ptr + 1;
}
if (prefix_len) {
char *name;
name = malloc(prefix_len);
if (!name)
return -ENOMEM;
strncpy(name, attr0, prefix_len - 1);
name[prefix_len - 1] = '\0';
DEBUG("Setting name of channel %s to %s\n", chn->id, name);
chn->name = name;
/* Shrink the attribute name */
for (i = 0; i < chn->nb_attrs; i++)
strcut(chn->attrs[i].name, prefix_len);
for (i = 0; i < pdata->nb_protected_attrs; i++)
strcut(pdata->protected_attrs[i].name, prefix_len);
}
return 0;
}
/*
* Used to generate the timeout parameter for operations like poll. Returns the
* number of ms until it is timeout_rel ms after the time specified in start. If
* timeout_rel is 0 returns -1 to indicate no timeout.
*
* The timeout that is specified for IIO operations is the maximum time a buffer
* push() or refill() operation should take before returning. poll() is used to
* wait for either data activity or for the timeout to elapse. poll() might get
* interrupted in which case it is called again or the read()/write() operation
* might not complete the full buffer size in one call in which case we go back
* to poll() again as well. Passing the same timeout as before would increase
* the total timeout and if repeated interruptions occur (e.g. by a timer
* signal) the operation might never time out or with significant delay. Hence
* before each poll() invocation the timeout is recalculated relative to the
* start of refill() or push() operation.
*/
static int get_rel_timeout_ms(struct timespec *start, unsigned int timeout_rel)
{
struct timespec now;
int diff_ms;
if (timeout_rel == 0) /* No timeout */
return -1;
clock_gettime(CLOCK_MONOTONIC, &now);
diff_ms = (now.tv_sec - start->tv_sec) * 1000;
diff_ms += (now.tv_nsec - start->tv_nsec) / 1000000;
if (diff_ms >= timeout_rel) /* Expired */
return 0;
if (diff_ms > 0) /* Should never be false, but lets be safe */
timeout_rel -= diff_ms;
if (timeout_rel > INT_MAX)
return INT_MAX;
return (int) timeout_rel;
}
static int device_check_ready(const struct iio_device *dev, short events,
struct timespec *start)
{
struct pollfd pollfd[2] = {
{
.fd = dev->pdata->fd,
.events = events,
}, {
.fd = dev->pdata->cancel_fd,
.events = POLLIN,
}
};
unsigned int rw_timeout_ms = dev->ctx->pdata->rw_timeout_ms;
int timeout_rel;
int ret;
if (!dev->pdata->blocking)
return 0;
do {
timeout_rel = get_rel_timeout_ms(start, rw_timeout_ms);
ret = poll(pollfd, 2, timeout_rel);
} while (ret == -1 && errno == EINTR);
if ((pollfd[1].revents & POLLIN))
return -EBADF;
if (ret < 0)
return -errno;
if (!ret)
return -ETIMEDOUT;
if (pollfd[0].revents & POLLNVAL)
return -EBADF;
if (!(pollfd[0].revents & events))
return -EIO;
return 0;
}
static ssize_t local_read(const struct iio_device *dev,
void *dst, size_t len, uint32_t *mask, size_t words)
{
struct iio_device_pdata *pdata = dev->pdata;
uintptr_t ptr = (uintptr_t) dst;
struct timespec start;
ssize_t readsize;
ssize_t ret;
if (pdata->fd == -1)
return -EBADF;
if (words != dev->words)
return -EINVAL;
memcpy(mask, dev->mask, words);
if (len == 0)
return 0;
clock_gettime(CLOCK_MONOTONIC, &start);
while (len > 0) {
ret = device_check_ready(dev, POLLIN, &start);
if (ret < 0)
break;
do {
ret = read(pdata->fd, (void *) ptr, len);
} while (ret == -1 && errno == EINTR);
if (ret == -1) {
if (pdata->blocking && errno == EAGAIN)
continue;
ret = -errno;
break;
} else if (ret == 0) {
ret = -EIO;
break;
}
ptr += ret;
len -= ret;
}
readsize = (ssize_t)(ptr - (uintptr_t) dst);
if ((ret > 0 || ret == -EAGAIN) && (readsize > 0))
return readsize;
else
return ret;
}
static ssize_t local_write(const struct iio_device *dev,
const void *src, size_t len)
{
struct iio_device_pdata *pdata = dev->pdata;
uintptr_t ptr = (uintptr_t) src;
struct timespec start;
ssize_t writtensize;
ssize_t ret;
if (pdata->fd == -1)
return -EBADF;
if (len == 0)
return 0;
clock_gettime(CLOCK_MONOTONIC, &start);
while (len > 0) {
ret = device_check_ready(dev, POLLOUT, &start);
if (ret < 0)
break;
do {
ret = write(pdata->fd, (void *) ptr, len);
} while (ret == -1 && errno == EINTR);
if (ret == -1) {
if (pdata->blocking && errno == EAGAIN)
continue;
ret = -errno;
break;
} else if (ret == 0) {
ret = -EIO;
break;
}
ptr += ret;
len -= ret;
}
writtensize = (ssize_t)(ptr - (uintptr_t) src);
if ((ret > 0 || ret == -EAGAIN) && (writtensize > 0))
return writtensize;
else
return ret;
}
static ssize_t local_enable_buffer(const struct iio_device *dev)
{
struct iio_device_pdata *pdata = dev->pdata;
ssize_t ret = 0;
if (!pdata->buffer_enabled) {
ret = local_write_dev_attr(dev,
"buffer/enable", "1", 2, false);
if (ret >= 0)
pdata->buffer_enabled = true;
}
return 0;
}
static int local_set_kernel_buffers_count(const struct iio_device *dev,
unsigned int nb_blocks)
{
struct iio_device_pdata *pdata = dev->pdata;
if (pdata->fd != -1)
return -EBUSY;
pdata->max_nb_blocks = nb_blocks;
return 0;
}
static ssize_t local_get_buffer(const struct iio_device *dev,
void **addr_ptr, size_t bytes_used,
uint32_t *mask, size_t words)
{
struct block block;
struct iio_device_pdata *pdata = dev->pdata;
struct timespec start;
char err_str[1024];
int f = pdata->fd;
ssize_t ret;
if (!pdata->is_high_speed)
return -ENOSYS;
if (f == -1)
return -EBADF;
if (!addr_ptr)
return -EINVAL;
if (pdata->last_dequeued >= 0) {
struct block *last_block = &pdata->blocks[pdata->last_dequeued];
if (pdata->cyclic) {
if (pdata->cyclic_buffer_enqueued)
return -EBUSY;
pdata->blocks[0].flags |= BLOCK_FLAG_CYCLIC;
pdata->cyclic_buffer_enqueued = true;
}
last_block->bytes_used = bytes_used;
ret = (ssize_t) ioctl_nointr(f,
BLOCK_ENQUEUE_IOCTL, last_block);
if (ret) {
ret = (ssize_t) -errno;
iio_strerror(errno, err_str, sizeof(err_str));
ERROR("Unable to enqueue block: %s\n", err_str);
return ret;
}
if (pdata->cyclic) {
*addr_ptr = pdata->addrs[pdata->last_dequeued];
return (ssize_t) last_block->bytes_used;
}
pdata->last_dequeued = -1;
}
clock_gettime(CLOCK_MONOTONIC, &start);
do {
ret = (ssize_t) device_check_ready(dev, POLLIN | POLLOUT, &start);
if (ret < 0)
return ret;
memset(&block, 0, sizeof(block));
ret = (ssize_t) ioctl_nointr(f, BLOCK_DEQUEUE_IOCTL, &block);
} while (pdata->blocking && ret == -1 && errno == EAGAIN);
if (ret) {
ret = (ssize_t) -errno;
if ((!pdata->blocking && ret != -EAGAIN) ||
(pdata->blocking && ret != -ETIMEDOUT)) {
iio_strerror(errno, err_str, sizeof(err_str));
ERROR("Unable to dequeue block: %s\n", err_str);
}
return ret;
}
/* Requested buffer size is too big! */
if (pdata->last_dequeued < 0 && bytes_used != block.size)
return -EFBIG;
pdata->last_dequeued = block.id;
*addr_ptr = pdata->addrs[block.id];
return (ssize_t) block.bytes_used;
}
static ssize_t local_read_all_dev_attrs(const struct iio_device *dev,
char *dst, size_t len, enum iio_attr_type type)
{
unsigned int i, nb;
char **attrs;
char *ptr = dst;
switch (type) {
case IIO_ATTR_TYPE_DEVICE:
nb = dev->nb_attrs;
attrs = dev->attrs;
break;
case IIO_ATTR_TYPE_DEBUG:
nb = dev->nb_debug_attrs;
attrs = dev->debug_attrs;
break;
case IIO_ATTR_TYPE_BUFFER:
nb = dev->nb_buffer_attrs;
attrs = dev->buffer_attrs;
break;
default:
return -EINVAL;
break;
}
for (i = 0; len >= 4 && i < nb; i++) {
/* Recursive! */
ssize_t ret = local_read_dev_attr(dev, attrs[i],
ptr + 4, len - 4, type);
*(uint32_t *) ptr = iio_htobe32(ret);
/* Align the length to 4 bytes */
if (ret > 0 && ret & 3)
ret = ((ret >> 2) + 1) << 2;
ptr += 4 + (ret < 0 ? 0 : ret);
len -= 4 + (ret < 0 ? 0 : ret);
}
return ptr - dst;
}
static ssize_t local_read_all_chn_attrs(const struct iio_channel *chn,
char *dst, size_t len)
{
unsigned int i;
char *ptr = dst;
for (i = 0; len >= 4 && i < chn->nb_attrs; i++) {
/* Recursive! */
ssize_t ret = local_read_chn_attr(chn,
chn->attrs[i].name, ptr + 4, len - 4);
*(uint32_t *) ptr = iio_htobe32(ret);
/* Align the length to 4 bytes */
if (ret > 0 && ret & 3)
ret = ((ret >> 2) + 1) << 2;
ptr += 4 + (ret < 0 ? 0 : ret);
len -= 4 + (ret < 0 ? 0 : ret);
}
return ptr - dst;
}
static int local_buffer_analyze(unsigned int nb, const char *src, size_t len)
{
while (nb--) {
int32_t val;
if (len < 4)
return -EINVAL;
val = (int32_t) iio_be32toh(*(uint32_t *) src);
src += 4;
len -= 4;
if (val > 0) {
if ((uint32_t) val > len)
return -EINVAL;
/* Align the length to 4 bytes */
if (val & 3)
val = ((val >> 2) + 1) << 2;
len -= val;
src += val;
}
}
/* We should have analyzed the whole buffer by now */
return !len ? 0 : -EINVAL;
}
static ssize_t local_write_all_dev_attrs(const struct iio_device *dev,
const char *src, size_t len, enum iio_attr_type type)
{
unsigned int i, nb;
char **attrs;
const char *ptr = src;
switch (type) {
case IIO_ATTR_TYPE_DEVICE:
nb = dev->nb_attrs;
attrs = dev->attrs;
break;
case IIO_ATTR_TYPE_DEBUG:
nb = dev->nb_debug_attrs;
attrs = dev->debug_attrs;
break;
case IIO_ATTR_TYPE_BUFFER:
nb = dev->nb_buffer_attrs;
attrs = dev->buffer_attrs;
break;
default:
return -EINVAL;
break;
}
/* First step: Verify that the buffer is in the correct format */
if (local_buffer_analyze(nb, src, len))
return -EINVAL;
/* Second step: write the attributes */
for (i = 0; i < nb; i++) {
int32_t val = (int32_t) iio_be32toh(*(uint32_t *) ptr);
ptr += 4;
if (val > 0) {
local_write_dev_attr(dev, attrs[i], ptr, val, type);
/* Align the length to 4 bytes */
if (val & 3)
val = ((val >> 2) + 1) << 2;
ptr += val;
}
}
return ptr - src;
}
static ssize_t local_write_all_chn_attrs(const struct iio_channel *chn,
const char *src, size_t len)
{
unsigned int i, nb = chn->nb_attrs;
const char *ptr = src;
/* First step: Verify that the buffer is in the correct format */
if (local_buffer_analyze(nb, src, len))
return -EINVAL;
/* Second step: write the attributes */
for (i = 0; i < nb; i++) {
int32_t val = (int32_t) iio_be32toh(*(uint32_t *) ptr);
ptr += 4;
if (val > 0) {
local_write_chn_attr(chn, chn->attrs[i].name, ptr, val);
/* Align the length to 4 bytes */
if (val & 3)
val = ((val >> 2) + 1) << 2;
ptr += val;
}
}
return ptr - src;
}
static ssize_t local_read_dev_attr(const struct iio_device *dev,
const char *attr, char *dst, size_t len, enum iio_attr_type type)
{
FILE *f;
char buf[1024];
ssize_t ret;
if (!attr)
return local_read_all_dev_attrs(dev, dst, len, type);
switch (type) {
case IIO_ATTR_TYPE_DEVICE:
iio_snprintf(buf, sizeof(buf), "/sys/bus/iio/devices/%s/%s",
dev->id, attr);
break;
case IIO_ATTR_TYPE_DEBUG:
iio_snprintf(buf, sizeof(buf), "/sys/kernel/debug/iio/%s/%s",
dev->id, attr);
break;
case IIO_ATTR_TYPE_BUFFER:
iio_snprintf(buf, sizeof(buf), "/sys/bus/iio/devices/%s/buffer/%s",
dev->id, attr);
break;
default:
return -EINVAL;
}
f = fopen(buf, "re");
if (!f)
return -errno;
ret = fread(dst, 1, len, f);
if (ret > 0)
dst[ret - 1] = '\0';
fflush(f);
if (ferror(f))
ret = -errno;
fclose(f);
return ret ? ret : -EIO;
}
static ssize_t local_write_dev_attr(const struct iio_device *dev,
const char *attr, const char *src, size_t len, enum iio_attr_type type)
{
FILE *f;
char buf[1024];
ssize_t ret;
if (!attr)
return local_write_all_dev_attrs(dev, src, len, type);
switch (type) {
case IIO_ATTR_TYPE_DEVICE:
iio_snprintf(buf, sizeof(buf), "/sys/bus/iio/devices/%s/%s",
dev->id, attr);
break;
case IIO_ATTR_TYPE_DEBUG:
iio_snprintf(buf, sizeof(buf), "/sys/kernel/debug/iio/%s/%s",
dev->id, attr);
break;
case IIO_ATTR_TYPE_BUFFER:
iio_snprintf(buf, sizeof(buf), "/sys/bus/iio/devices/%s/buffer/%s",
dev->id, attr);
break;
default:
return -EINVAL;
}
f = fopen(buf, "we");
if (!f)
return -errno;
ret = fwrite(src, 1, len, f);
fflush(f);
if (ferror(f))
ret = -errno;
fclose(f);
return ret ? ret : -EIO;
}
static const char * get_filename(const struct iio_channel *chn,
const char *attr)
{
unsigned int i;
for (i = 0; i < chn->nb_attrs; i++)
if (!strcmp(attr, chn->attrs[i].name))
return chn->attrs[i].filename;
return attr;
}
static ssize_t local_read_chn_attr(const struct iio_channel *chn,
const char *attr, char *dst, size_t len)
{
if (!attr)
return local_read_all_chn_attrs(chn, dst, len);
attr = get_filename(chn, attr);
return local_read_dev_attr(chn->dev, attr, dst, len, false);
}
static ssize_t local_write_chn_attr(const struct iio_channel *chn,
const char *attr, const char *src, size_t len)
{
if (!attr)
return local_write_all_chn_attrs(chn, src, len);
attr = get_filename(chn, attr);
return local_write_dev_attr(chn->dev, attr, src, len, false);
}
static int channel_write_state(const struct iio_channel *chn, bool en)
{
ssize_t ret;
if (!chn->pdata->enable_fn) {
ERROR("Libiio bug: No \"en\" attribute parsed\n");
return -EINVAL;
}
ret = local_write_chn_attr(chn, chn->pdata->enable_fn, en ? "1" : "0", 2);
if (ret < 0)
return (int) ret;
else
return 0;
}
static int enable_high_speed(const struct iio_device *dev)
{
struct block_alloc_req req;
struct iio_device_pdata *pdata = dev->pdata;
unsigned int nb_blocks;
unsigned int i;
int ret, fd = pdata->fd;
/*
* For the BLOCK_ALLOC_IOCTL ioctl it is not possible to distingush
* between an error during the allocation (e.g. incorrect size) or
* whether the high-speed interface is not supported. BLOCK_FREE_IOCTL does
* never fail if the device supports the high-speed interface, so we use it
* here. Calling it when no blocks are allocated the ioctl has no effect.
*/
ret = ioctl_nointr(fd, BLOCK_FREE_IOCTL, NULL);
if (ret < 0)
return -ENOSYS;
if (pdata->cyclic) {
nb_blocks = 1;
DEBUG("Enabling cyclic mode\n");
} else {
nb_blocks = pdata->max_nb_blocks;
DEBUG("Cyclic mode not enabled\n");
}
pdata->blocks = calloc(nb_blocks, sizeof(*pdata->blocks));
if (!pdata->blocks)
return -ENOMEM;
pdata->addrs = calloc(nb_blocks, sizeof(*pdata->addrs));
if (!pdata->addrs) {
free(pdata->blocks);
pdata->blocks = NULL;
return -ENOMEM;
}
req.id = 0;
req.type = 0;
req.size = pdata->samples_count *
iio_device_get_sample_size_mask(dev, dev->mask, dev->words);
req.count = nb_blocks;
ret = ioctl_nointr(fd, BLOCK_ALLOC_IOCTL, &req);
if (ret < 0) {
ret = -errno;
goto err_freemem;
}
if (req.count == 0) {
ret = -ENOMEM;
goto err_block_free;
}
/* We might get less blocks than what we asked for */
pdata->allocated_nb_blocks = req.count;
/* mmap all the blocks */
for (i = 0; i < pdata->allocated_nb_blocks; i++) {
pdata->blocks[i].id = i;
ret = ioctl_nointr(fd, BLOCK_QUERY_IOCTL, &pdata->blocks[i]);
if (ret) {
ret = -errno;
goto err_munmap;
}
ret = ioctl_nointr(fd, BLOCK_ENQUEUE_IOCTL, &pdata->blocks[i]);
if (ret) {
ret = -errno;
goto err_munmap;
}
pdata->addrs[i] = mmap(0, pdata->blocks[i].size,
PROT_READ | PROT_WRITE,
MAP_SHARED, fd, pdata->blocks[i].offset);
if (pdata->addrs[i] == MAP_FAILED) {
ret = -errno;
goto err_munmap;
}
}
pdata->last_dequeued = -1;
return 0;
err_munmap:
for (; i > 0; i--)
munmap(pdata->addrs[i - 1], pdata->blocks[i - 1].size);
err_block_free:
ioctl_nointr(fd, BLOCK_FREE_IOCTL, 0);
pdata->allocated_nb_blocks = 0;
err_freemem:
free(pdata->addrs);
pdata->addrs = NULL;
free(pdata->blocks);
pdata->blocks = NULL;
return ret;
}
static int local_open(const struct iio_device *dev,
size_t samples_count, bool cyclic)
{
unsigned int i;
int ret;
char buf[1024];
struct iio_device_pdata *pdata = dev->pdata;
if (pdata->fd != -1)
return -EBUSY;
ret = local_write_dev_attr(dev, "buffer/enable", "0", 2, false);
if (ret < 0)
return ret;
iio_snprintf(buf, sizeof(buf), "%lu", (unsigned long) samples_count);
ret = local_write_dev_attr(dev, "buffer/length",
buf, strlen(buf) + 1, false);
if (ret < 0)
return ret;
pdata->cancel_fd = eventfd(0, EFD_CLOEXEC | EFD_NONBLOCK);
if (pdata->cancel_fd == -1)
return -errno;
iio_snprintf(buf, sizeof(buf), "/dev/%s", dev->id);
pdata->fd = open(buf, O_RDWR | O_CLOEXEC | O_NONBLOCK);
if (pdata->fd == -1) {
ret = -errno;
goto err_close_cancel_fd;
}
/* Disable channels */
for (i = 0; i < dev->nb_channels; i++) {
struct iio_channel *chn = dev->channels[i];
if (chn->index >= 0 && !iio_channel_is_enabled(chn)) {
ret = channel_write_state(chn, false);
if (ret < 0)
goto err_close;
}
}
/* Enable channels */
for (i = 0; i < dev->nb_channels; i++) {
struct iio_channel *chn = dev->channels[i];
if (chn->index >= 0 && iio_channel_is_enabled(chn)) {
ret = channel_write_state(chn, true);
if (ret < 0)
goto err_close;
}
}
pdata->cyclic = cyclic;
pdata->cyclic_buffer_enqueued = false;
pdata->buffer_enabled = false;
pdata->samples_count = samples_count;
ret = enable_high_speed(dev);
if (ret < 0 && ret != -ENOSYS)
goto err_close;
pdata->is_high_speed = !ret;
if (!pdata->is_high_speed) {
unsigned long size = samples_count * pdata->max_nb_blocks;
WARNING("High-speed mode not enabled\n");
/* Cyclic mode is only supported in high-speed mode */
if (cyclic) {
ret = -EPERM;
goto err_close;
}
/* Increase the size of the kernel buffer, when using the
* low-speed interface. This avoids losing samples when
* refilling the iio_buffer. */
iio_snprintf(buf, sizeof(buf), "%lu", size);
ret = local_write_dev_attr(dev, "buffer/length",
buf, strlen(buf) + 1, false);
if (ret < 0)
goto err_close;
}
ret = local_enable_buffer(dev);
if (ret < 0)
goto err_close;
return 0;
err_close:
close(pdata->fd);
pdata->fd = -1;
err_close_cancel_fd: