linux/drivers/iio/industrialio-buffer.c
Greg Kroah-Hartman bd972ff317 One new driver and a couple of nice cleanups.
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Merge tag 'togreg-3.6a' of git://git.kernel.org/pub/scm/linux/kernel/git/jic23/iio into staging-next

IIO: One new driver and a couple of nice cleanups.
2012-07-12 12:29:44 -07:00

792 lines
20 KiB
C

/* The industrial I/O core
*
* Copyright (c) 2008 Jonathan Cameron
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 as published by
* the Free Software Foundation.
*
* 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/iio/iio.h>
#include "iio_core.h"
#include <linux/iio/sysfs.h>
#include <linux/iio/buffer.h>
static const char * const iio_endian_prefix[] = {
[IIO_BE] = "be",
[IIO_LE] = "le",
};
/**
* iio_buffer_read_first_n_outer() - chrdev read for buffer access
*
* This function relies on all buffer implementations having an
* iio_buffer as their first element.
**/
ssize_t iio_buffer_read_first_n_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;
if (!rb || !rb->access->read_first_n)
return -EINVAL;
return rb->access->read_first_n(rb, n, buf);
}
/**
* iio_buffer_poll() - poll the buffer to find out if it has data
*/
unsigned int 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;
poll_wait(filp, &rb->pollq, wait);
if (rb->stufftoread)
return POLLIN | POLLRDNORM;
/* need a way of knowing if there may be enough data... */
return 0;
}
void iio_buffer_init(struct iio_buffer *buffer)
{
INIT_LIST_HEAD(&buffer->demux_list);
init_waitqueue_head(&buffer->pollq);
}
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
}
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);
ret = test_bit(to_iio_dev_attr(attr)->address,
indio_dev->buffer->scan_mask);
return sprintf(buf, "%d\n", ret);
}
static int iio_scan_mask_clear(struct iio_buffer *buffer, int bit)
{
clear_bit(bit, buffer->scan_mask);
return 0;
}
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_enabled(indio_dev)) {
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);
return sprintf(buf, "%d\n", indio_dev->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);
bool state;
ret = strtobool(buf, &state);
if (ret < 0)
return ret;
mutex_lock(&indio_dev->mlock);
if (iio_buffer_enabled(indio_dev)) {
ret = -EBUSY;
goto error_ret;
}
indio_dev->buffer->scan_timestamp = state;
indio_dev->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,
const struct iio_chan_spec *chan)
{
int ret, attrcount = 0;
struct iio_buffer *buffer = indio_dev->buffer;
ret = __iio_add_chan_devattr("index",
chan,
&iio_show_scan_index,
NULL,
0,
0,
&indio_dev->dev,
&buffer->scan_el_dev_attr_list);
if (ret)
goto error_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)
goto error_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);
attrcount++;
ret = attrcount;
error_ret:
return ret;
}
static void iio_buffer_remove_and_free_scan_dev_attr(struct iio_dev *indio_dev,
struct iio_dev_attr *p)
{
kfree(p->dev_attr.attr.name);
kfree(p);
}
static void __iio_buffer_attr_cleanup(struct iio_dev *indio_dev)
{
struct iio_dev_attr *p, *n;
struct iio_buffer *buffer = indio_dev->buffer;
list_for_each_entry_safe(p, n,
&buffer->scan_el_dev_attr_list, l)
iio_buffer_remove_and_free_scan_dev_attr(indio_dev, p);
}
static const char * const iio_scan_elements_group_name = "scan_elements";
int iio_buffer_register(struct iio_dev *indio_dev,
const struct iio_chan_spec *channels,
int num_channels)
{
struct iio_dev_attr *p;
struct attribute **attr;
struct iio_buffer *buffer = indio_dev->buffer;
int ret, i, attrn, attrcount, attrcount_orig = 0;
if (buffer->attrs)
indio_dev->groups[indio_dev->groupcounter++] = buffer->attrs;
if (buffer->scan_el_attrs != NULL) {
attr = buffer->scan_el_attrs->attrs;
while (*attr++ != NULL)
attrcount_orig++;
}
attrcount = attrcount_orig;
INIT_LIST_HEAD(&buffer->scan_el_dev_attr_list);
if (channels) {
/* new magic */
for (i = 0; i < num_channels; i++) {
if (channels[i].scan_index < 0)
continue;
/* Establish necessary mask length */
if (channels[i].scan_index >
(int)indio_dev->masklength - 1)
indio_dev->masklength
= channels[i].scan_index + 1;
ret = iio_buffer_add_channel_sysfs(indio_dev,
&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 = kcalloc(BITS_TO_LONGS(indio_dev->masklength),
sizeof(*buffer->scan_mask),
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;
}
if (buffer->scan_el_attrs)
memcpy(buffer->scan_el_group.attrs, buffer->scan_el_attrs,
sizeof(buffer->scan_el_group.attrs[0])*attrcount_orig);
attrn = attrcount_orig;
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:
kfree(buffer->scan_mask);
error_cleanup_dynamic:
__iio_buffer_attr_cleanup(indio_dev);
return ret;
}
EXPORT_SYMBOL(iio_buffer_register);
void iio_buffer_unregister(struct iio_dev *indio_dev)
{
kfree(indio_dev->buffer->scan_mask);
kfree(indio_dev->buffer->scan_el_group.attrs);
__iio_buffer_attr_cleanup(indio_dev);
}
EXPORT_SYMBOL(iio_buffer_unregister);
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;
if (buffer->access->get_length)
return sprintf(buf, "%d\n",
buffer->access->get_length(buffer));
return 0;
}
EXPORT_SYMBOL(iio_buffer_read_length);
ssize_t iio_buffer_write_length(struct device *dev,
struct device_attribute *attr,
const char *buf,
size_t len)
{
int ret;
ulong val;
struct iio_dev *indio_dev = dev_to_iio_dev(dev);
struct iio_buffer *buffer = indio_dev->buffer;
ret = strict_strtoul(buf, 10, &val);
if (ret)
return ret;
if (buffer->access->get_length)
if (val == buffer->access->get_length(buffer))
return len;
mutex_lock(&indio_dev->mlock);
if (iio_buffer_enabled(indio_dev)) {
ret = -EBUSY;
} else {
if (buffer->access->set_length)
buffer->access->set_length(buffer, val);
ret = 0;
}
mutex_unlock(&indio_dev->mlock);
return ret ? ret : len;
}
EXPORT_SYMBOL(iio_buffer_write_length);
ssize_t iio_buffer_store_enable(struct device *dev,
struct device_attribute *attr,
const char *buf,
size_t len)
{
int ret;
bool requested_state, current_state;
int previous_mode;
struct iio_dev *indio_dev = dev_to_iio_dev(dev);
struct iio_buffer *buffer = indio_dev->buffer;
mutex_lock(&indio_dev->mlock);
previous_mode = indio_dev->currentmode;
requested_state = !(buf[0] == '0');
current_state = iio_buffer_enabled(indio_dev);
if (current_state == requested_state) {
printk(KERN_INFO "iio-buffer, current state requested again\n");
goto done;
}
if (requested_state) {
if (indio_dev->setup_ops->preenable) {
ret = indio_dev->setup_ops->preenable(indio_dev);
if (ret) {
printk(KERN_ERR
"Buffer not started:"
"buffer preenable failed\n");
goto error_ret;
}
}
if (buffer->access->request_update) {
ret = buffer->access->request_update(buffer);
if (ret) {
printk(KERN_INFO
"Buffer not started:"
"buffer parameter update failed\n");
goto error_ret;
}
}
/* Definitely possible for devices to support both of these.*/
if (indio_dev->modes & INDIO_BUFFER_TRIGGERED) {
if (!indio_dev->trig) {
printk(KERN_INFO
"Buffer not started: no trigger\n");
ret = -EINVAL;
goto error_ret;
}
indio_dev->currentmode = INDIO_BUFFER_TRIGGERED;
} else if (indio_dev->modes & INDIO_BUFFER_HARDWARE)
indio_dev->currentmode = INDIO_BUFFER_HARDWARE;
else { /* should never be reached */
ret = -EINVAL;
goto error_ret;
}
if (indio_dev->setup_ops->postenable) {
ret = indio_dev->setup_ops->postenable(indio_dev);
if (ret) {
printk(KERN_INFO
"Buffer not started:"
"postenable failed\n");
indio_dev->currentmode = previous_mode;
if (indio_dev->setup_ops->postdisable)
indio_dev->setup_ops->
postdisable(indio_dev);
goto error_ret;
}
}
} else {
if (indio_dev->setup_ops->predisable) {
ret = indio_dev->setup_ops->predisable(indio_dev);
if (ret)
goto error_ret;
}
indio_dev->currentmode = INDIO_DIRECT_MODE;
if (indio_dev->setup_ops->postdisable) {
ret = indio_dev->setup_ops->postdisable(indio_dev);
if (ret)
goto error_ret;
}
}
done:
mutex_unlock(&indio_dev->mlock);
return len;
error_ret:
mutex_unlock(&indio_dev->mlock);
return ret;
}
EXPORT_SYMBOL(iio_buffer_store_enable);
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);
return sprintf(buf, "%d\n", iio_buffer_enabled(indio_dev));
}
EXPORT_SYMBOL(iio_buffer_show_enable);
/* 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)
{
if (bitmap_empty(mask, masklength))
return NULL;
while (*av_masks) {
if (bitmap_subset(mask, av_masks, masklength))
return av_masks;
av_masks += BITS_TO_LONGS(masklength);
}
return NULL;
}
static int iio_compute_scan_bytes(struct iio_dev *indio_dev, const long *mask,
bool timestamp)
{
const struct iio_chan_spec *ch;
unsigned bytes = 0;
int length, i;
/* How much space will the demuxed element take? */
for_each_set_bit(i, mask,
indio_dev->masklength) {
ch = iio_find_channel_from_si(indio_dev, i);
length = ch->scan_type.storagebits / 8;
bytes = ALIGN(bytes, length);
bytes += length;
}
if (timestamp) {
ch = iio_find_channel_from_si(indio_dev,
indio_dev->scan_index_timestamp);
length = ch->scan_type.storagebits / 8;
bytes = ALIGN(bytes, length);
bytes += length;
}
return bytes;
}
int iio_sw_buffer_preenable(struct iio_dev *indio_dev)
{
struct iio_buffer *buffer = indio_dev->buffer;
dev_dbg(&indio_dev->dev, "%s\n", __func__);
/* How much space will the demuxed element take? */
indio_dev->scan_bytes =
iio_compute_scan_bytes(indio_dev, buffer->scan_mask,
buffer->scan_timestamp);
buffer->access->set_bytes_per_datum(buffer, indio_dev->scan_bytes);
/* What scan mask do we actually have ?*/
if (indio_dev->available_scan_masks)
indio_dev->active_scan_mask =
iio_scan_mask_match(indio_dev->available_scan_masks,
indio_dev->masklength,
buffer->scan_mask);
else
indio_dev->active_scan_mask = buffer->scan_mask;
if (indio_dev->active_scan_mask == NULL)
return -EINVAL;
iio_update_demux(indio_dev);
if (indio_dev->info->update_scan_mode)
return indio_dev->info
->update_scan_mode(indio_dev,
indio_dev->active_scan_mask);
return 0;
}
EXPORT_SYMBOL(iio_sw_buffer_preenable);
/**
* 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 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
* @buffer: the buffer whose scan mask we are interested in
* @bit: the bit to be set.
**/
int iio_scan_mask_set(struct iio_dev *indio_dev,
struct iio_buffer *buffer, int bit)
{
const unsigned long *mask;
unsigned long *trialmask;
trialmask = kmalloc(sizeof(*trialmask)*
BITS_TO_LONGS(indio_dev->masklength),
GFP_KERNEL);
if (trialmask == NULL)
return -ENOMEM;
if (!indio_dev->masklength) {
WARN_ON("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);
if (!mask)
goto err_invalid_mask;
}
bitmap_copy(buffer->scan_mask, trialmask, indio_dev->masklength);
kfree(trialmask);
return 0;
err_invalid_mask:
kfree(trialmask);
return -EINVAL;
}
EXPORT_SYMBOL_GPL(iio_scan_mask_set);
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;
return test_bit(bit, buffer->scan_mask);
};
EXPORT_SYMBOL_GPL(iio_scan_mask_query);
/**
* 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 unsigned char *iio_demux(struct iio_buffer *buffer,
unsigned char *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;
}
int iio_push_to_buffer(struct iio_buffer *buffer, unsigned char *data,
s64 timestamp)
{
unsigned char *dataout = iio_demux(buffer, data);
return buffer->access->store_to(buffer, dataout, timestamp);
}
EXPORT_SYMBOL_GPL(iio_push_to_buffer);
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);
}
}
int iio_update_demux(struct iio_dev *indio_dev)
{
const struct iio_chan_spec *ch;
struct iio_buffer *buffer = indio_dev->buffer;
int ret, in_ind = -1, out_ind, length;
unsigned in_loc = 0, out_loc = 0;
struct iio_demux_table *p;
/* 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,
indio_dev->active_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) {
in_ind = find_next_bit(indio_dev->active_scan_mask,
indio_dev->masklength,
in_ind + 1);
ch = iio_find_channel_from_si(indio_dev, in_ind);
length = ch->scan_type.storagebits/8;
/* Make sure we are aligned */
in_loc += length;
if (in_loc % length)
in_loc += length - in_loc % length;
}
p = kmalloc(sizeof(*p), GFP_KERNEL);
if (p == NULL) {
ret = -ENOMEM;
goto error_clear_mux_table;
}
ch = iio_find_channel_from_si(indio_dev, in_ind);
length = ch->scan_type.storagebits/8;
if (out_loc % length)
out_loc += length - out_loc % length;
if (in_loc % length)
in_loc += length - in_loc % length;
p->from = in_loc;
p->to = out_loc;
p->length = length;
list_add_tail(&p->l, &buffer->demux_list);
out_loc += length;
in_loc += length;
}
/* Relies on scan_timestamp being last */
if (buffer->scan_timestamp) {
p = kmalloc(sizeof(*p), GFP_KERNEL);
if (p == NULL) {
ret = -ENOMEM;
goto error_clear_mux_table;
}
ch = iio_find_channel_from_si(indio_dev,
indio_dev->scan_index_timestamp);
length = ch->scan_type.storagebits/8;
if (out_loc % length)
out_loc += length - out_loc % length;
if (in_loc % length)
in_loc += length - in_loc % length;
p->from = in_loc;
p->to = out_loc;
p->length = length;
list_add_tail(&p->l, &buffer->demux_list);
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;
}
EXPORT_SYMBOL_GPL(iio_update_demux);