diff options
Diffstat (limited to 'drivers/iio/industrialio-buffer.c')
| -rw-r--r-- | drivers/iio/industrialio-buffer.c | 1262 |
1 files changed, 1262 insertions, 0 deletions
diff --git a/drivers/iio/industrialio-buffer.c b/drivers/iio/industrialio-buffer.c new file mode 100644 index 000000000..df919f44d --- /dev/null +++ b/drivers/iio/industrialio-buffer.c @@ -0,0 +1,1262 @@ +/* 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/sched.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", +}; + +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); + 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_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; + size_t datum_size; + size_t to_wait = 0; + size_t to_read; + int ret; + + if (!indio_dev->info) + return -ENODEV; + + if (!rb || !rb->access->read_first_n) + 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; + + to_read = min_t(size_t, n / datum_size, rb->watermark); + + if (!(filp->f_flags & O_NONBLOCK)) + to_wait = to_read; + + do { + ret = wait_event_interruptible(rb->pollq, + iio_buffer_ready(indio_dev, rb, to_wait, to_read)); + if (ret) + return ret; + + if (!indio_dev->info) + return -ENODEV; + + ret = rb->access->read_first_n(rb, n, buf); + if (ret == 0 && (filp->f_flags & O_NONBLOCK)) + ret = -EAGAIN; + } while (ret == 0); + + return ret; +} + +/** + * 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; + + if (!indio_dev->info) + return -ENODEV; + + poll_wait(filp, &rb->pollq, wait); + if (iio_buffer_ready(indio_dev, rb, rb->watermark, 0)) + return POLLIN | POLLRDNORM; + 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) +{ + if (!indio_dev->buffer) + return; + + wake_up(&indio_dev->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); + 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); + + /* Ensure ret is 0 or 1. */ + ret = !!test_bit(to_iio_dev_attr(attr)->address, + indio_dev->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) +{ + 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 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 = 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; +} + +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_is_active(indio_dev->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); + 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_is_active(indio_dev->buffer)) { + ret = -EBUSY; + goto error_ret; + } + indio_dev->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, + 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, + 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(indio_dev->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); + return sprintf(buf, "%d\n", iio_buffer_is_active(indio_dev->buffer)); +} + +static int iio_compute_scan_bytes(struct iio_dev *indio_dev, + const unsigned 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); + if (ch->scan_type.repeat > 1) + length = ch->scan_type.storagebits / 8 * + ch->scan_type.repeat; + else + 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); + if (ch->scan_type.repeat > 1) + length = ch->scan_type.storagebits / 8 * + ch->scan_type.repeat; + else + length = ch->scan_type.storagebits / 8; + bytes = ALIGN(bytes, length); + bytes += length; + } + return bytes; +} + +static void iio_buffer_activate(struct iio_dev *indio_dev, + struct iio_buffer *buffer) +{ + iio_buffer_get(buffer); + list_add(&buffer->buffer_list, &indio_dev->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); +} + +void iio_disable_all_buffers(struct iio_dev *indio_dev) +{ + struct iio_buffer *buffer, *_buffer; + + if (list_empty(&indio_dev->buffer_list)) + return; + + if (indio_dev->setup_ops->predisable) + indio_dev->setup_ops->predisable(indio_dev); + + list_for_each_entry_safe(buffer, _buffer, + &indio_dev->buffer_list, buffer_list) + iio_buffer_deactivate(buffer); + + indio_dev->currentmode = INDIO_DIRECT_MODE; + if (indio_dev->setup_ops->postdisable) + indio_dev->setup_ops->postdisable(indio_dev); + + if (indio_dev->available_scan_masks == NULL) + kfree(indio_dev->active_scan_mask); +} + +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_update_buffers(struct iio_dev *indio_dev, + struct iio_buffer *insert_buffer, + struct iio_buffer *remove_buffer) +{ + int ret; + int success = 0; + struct iio_buffer *buffer; + unsigned long *compound_mask; + const unsigned long *old_mask; + + /* Wind down existing buffers - iff there are any */ + if (!list_empty(&indio_dev->buffer_list)) { + if (indio_dev->setup_ops->predisable) { + ret = indio_dev->setup_ops->predisable(indio_dev); + if (ret) + return ret; + } + indio_dev->currentmode = INDIO_DIRECT_MODE; + if (indio_dev->setup_ops->postdisable) { + ret = indio_dev->setup_ops->postdisable(indio_dev); + if (ret) + return ret; + } + } + /* Keep a copy of current setup to allow roll back */ + old_mask = indio_dev->active_scan_mask; + if (!indio_dev->available_scan_masks) + indio_dev->active_scan_mask = NULL; + + 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(&indio_dev->buffer_list)) { + indio_dev->currentmode = INDIO_DIRECT_MODE; + if (indio_dev->available_scan_masks == NULL) + kfree(old_mask); + return 0; + } + + /* What scan mask do we actually have? */ + compound_mask = kcalloc(BITS_TO_LONGS(indio_dev->masklength), + sizeof(long), GFP_KERNEL); + if (compound_mask == NULL) { + if (indio_dev->available_scan_masks == NULL) + kfree(old_mask); + return -ENOMEM; + } + indio_dev->scan_timestamp = 0; + + list_for_each_entry(buffer, &indio_dev->buffer_list, buffer_list) { + bitmap_or(compound_mask, compound_mask, buffer->scan_mask, + indio_dev->masklength); + indio_dev->scan_timestamp |= buffer->scan_timestamp; + } + if (indio_dev->available_scan_masks) { + indio_dev->active_scan_mask = + iio_scan_mask_match(indio_dev->available_scan_masks, + indio_dev->masklength, + compound_mask); + if (indio_dev->active_scan_mask == NULL) { + /* + * Roll back. + * Note can only occur when adding a buffer. + */ + iio_buffer_deactivate(insert_buffer); + if (old_mask) { + indio_dev->active_scan_mask = old_mask; + success = -EINVAL; + } + else { + kfree(compound_mask); + ret = -EINVAL; + return ret; + } + } + } else { + indio_dev->active_scan_mask = compound_mask; + } + + iio_update_demux(indio_dev); + + /* Wind up again */ + 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 (%d)\n", ret); + goto error_remove_inserted; + } + } + indio_dev->scan_bytes = + iio_compute_scan_bytes(indio_dev, + indio_dev->active_scan_mask, + indio_dev->scan_timestamp); + list_for_each_entry(buffer, &indio_dev->buffer_list, buffer_list) { + iio_buffer_update_bytes_per_datum(indio_dev, buffer); + if (buffer->access->request_update) { + ret = buffer->access->request_update(buffer); + if (ret) { + printk(KERN_INFO + "Buffer not started: buffer parameter update failed (%d)\n", ret); + goto error_run_postdisable; + } + } + } + if (indio_dev->info->update_scan_mode) { + ret = indio_dev->info + ->update_scan_mode(indio_dev, + indio_dev->active_scan_mask); + if (ret < 0) { + printk(KERN_INFO "Buffer not started: update scan mode failed (%d)\n", ret); + goto error_run_postdisable; + } + } + /* Definitely possible for devices to support both of these. */ + if ((indio_dev->modes & INDIO_BUFFER_TRIGGERED) && indio_dev->trig) { + indio_dev->currentmode = INDIO_BUFFER_TRIGGERED; + } else if (indio_dev->modes & INDIO_BUFFER_HARDWARE) { + indio_dev->currentmode = INDIO_BUFFER_HARDWARE; + } else if (indio_dev->modes & INDIO_BUFFER_SOFTWARE) { + indio_dev->currentmode = INDIO_BUFFER_SOFTWARE; + } else { /* Should never be reached */ + /* Can only occur on first buffer */ + if (indio_dev->modes & INDIO_BUFFER_TRIGGERED) + pr_info("Buffer not started: no trigger\n"); + ret = -EINVAL; + goto error_run_postdisable; + } + + if (indio_dev->setup_ops->postenable) { + ret = indio_dev->setup_ops->postenable(indio_dev); + if (ret) { + printk(KERN_INFO + "Buffer not started: postenable failed (%d)\n", ret); + indio_dev->currentmode = INDIO_DIRECT_MODE; + if (indio_dev->setup_ops->postdisable) + indio_dev->setup_ops->postdisable(indio_dev); + goto error_disable_all_buffers; + } + } + + if (indio_dev->available_scan_masks) + kfree(compound_mask); + else + kfree(old_mask); + + return success; + +error_disable_all_buffers: + indio_dev->currentmode = INDIO_DIRECT_MODE; +error_run_postdisable: + if (indio_dev->setup_ops->postdisable) + indio_dev->setup_ops->postdisable(indio_dev); +error_remove_inserted: + if (insert_buffer) + iio_buffer_deactivate(insert_buffer); + indio_dev->active_scan_mask = old_mask; + kfree(compound_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); + +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); + 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(indio_dev->buffer); + /* Already in desired state */ + if (inlist == requested_state) + goto done; + + if (requested_state) + ret = __iio_update_buffers(indio_dev, + indio_dev->buffer, NULL); + else + ret = __iio_update_buffers(indio_dev, + NULL, indio_dev->buffer); + + if (ret < 0) + goto done; +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(indio_dev->buffer)) { + ret = -EBUSY; + goto out; + } + + buffer->watermark = val; + + if (indio_dev->info->hwfifo_set_watermark) + indio_dev->info->hwfifo_set_watermark(indio_dev, val); +out: + mutex_unlock(&indio_dev->mlock); + + return ret ? ret : len; +} + +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 attribute *iio_buffer_attrs[] = { + &dev_attr_length.attr, + &dev_attr_enable.attr, + &dev_attr_watermark.attr, +}; + +int iio_buffer_alloc_sysfs_and_mask(struct iio_dev *indio_dev) +{ + struct iio_dev_attr *p; + struct attribute **attr; + struct iio_buffer *buffer = indio_dev->buffer; + int ret, i, attrn, attrcount, attrcount_orig = 0; + const struct iio_chan_spec *channels; + + if (!buffer) + return 0; + + 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->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; + + 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); + channels = indio_dev->channels; + if (channels) { + /* new magic */ + for (i = 0; i < indio_dev->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_free_chan_devattr_list(&buffer->scan_el_dev_attr_list); + kfree(indio_dev->buffer->buffer_group.attrs); + + return ret; +} + +void iio_buffer_free_sysfs_and_mask(struct iio_dev *indio_dev) +{ + if (!indio_dev->buffer) + return; + + kfree(indio_dev->buffer->scan_mask); + kfree(indio_dev->buffer->buffer_group.attrs); + kfree(indio_dev->buffer->scan_el_group.attrs); + iio_free_chan_devattr_list(&indio_dev->buffer->scan_el_dev_attr_list); +} + +/** + * 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); + +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); +}; +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 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, POLLIN | POLLRDNORM); + return 0; +} + +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_push_to_buffers(struct iio_dev *indio_dev, const void *data) +{ + int ret; + struct iio_buffer *buf; + + list_for_each_entry(buf, &indio_dev->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); + +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) +{ + const struct iio_chan_spec *ch; + 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) { + 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); + if (ch->scan_type.repeat > 1) + length = ch->scan_type.storagebits / 8 * + ch->scan_type.repeat; + else + length = ch->scan_type.storagebits / 8; + /* Make sure we are aligned */ + in_loc = roundup(in_loc, length) + length; + } + ch = iio_find_channel_from_si(indio_dev, in_ind); + if (ch->scan_type.repeat > 1) + length = ch->scan_type.storagebits / 8 * + ch->scan_type.repeat; + else + length = ch->scan_type.storagebits / 8; + 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) { + ch = iio_find_channel_from_si(indio_dev, + indio_dev->scan_index_timestamp); + if (ch->scan_type.repeat > 1) + length = ch->scan_type.storagebits / 8 * + ch->scan_type.repeat; + else + length = ch->scan_type.storagebits / 8; + 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; +} + +int iio_update_demux(struct iio_dev *indio_dev) +{ + struct iio_buffer *buffer; + int ret; + + list_for_each_entry(buffer, &indio_dev->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, &indio_dev->buffer_list, buffer_list) + iio_buffer_demux_free(buffer); + + return ret; +} +EXPORT_SYMBOL_GPL(iio_update_demux); + +/** + * 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); |