diff options
Diffstat (limited to 'drivers/iio/industrialio-buffer.c')
| -rw-r--r-- | drivers/iio/industrialio-buffer.c | 755 |
1 files changed, 755 insertions, 0 deletions
diff --git a/drivers/iio/industrialio-buffer.c b/drivers/iio/industrialio-buffer.c new file mode 100644 index 00000000000..ac185b8694b --- /dev/null +++ b/drivers/iio/industrialio-buffer.c @@ -0,0 +1,755 @@ +/* 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++) { + /* Establish necessary mask length */ + if (channels[i].scan_index > + (int)indio_dev->masklength - 1) + indio_dev->masklength + = indio_dev->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; + 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_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"); + kfree(trialmask); + return -EINVAL; + } + bitmap_copy(trialmask, buffer->scan_mask, indio_dev->masklength); + set_bit(bit, trialmask); + + if (indio_dev->available_scan_masks) { + mask = iio_scan_mask_match(indio_dev->available_scan_masks, + indio_dev->masklength, + trialmask); + if (!mask) { + kfree(trialmask); + return -EINVAL; + } + } + bitmap_copy(buffer->scan_mask, trialmask, indio_dev->masklength); + + kfree(trialmask); + + return 0; +}; +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); |