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![Alexandru Ardelean](/assets/img/avatar_default.png)
This is similar to the {devm_}iio_triggered_buffer_setup_ext variants added
via commit 5164c78898
("iio: triggered-buffer: add
{devm_}iio_triggered_buffer_setup_ext variants").
These can be used to pass extra buffer attributes to the buffer object.
This is a bit of temporary mechanism (hopefully) so that drivers that want
to allocate a kfifo buffer with extra buffer attributes, don't need to
include 'buffer_impl.h' directly. This can also become an API function (in
it's own right, unfortunately), but it may be a little less bad vs drivers
having to include 'buffer_impl.h'.
So, far the drivers that want to pass buffer attributes, all have to do
with some HW FIFO attributes, so there may be a chance of unifying them
into IIO core somehow (as some standard API). But, until that happens, we
just need to let them register their HW FIFO attributes directly (without
having to let them include 'buffer_impl.h' directly).
Signed-off-by: Alexandru Ardelean <aardelean@deviqon.com>
Link: https://lore.kernel.org/r/20210311091042.22417-1-aardelean@deviqon.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
248 lines
5.8 KiB
C
248 lines
5.8 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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#include <linux/slab.h>
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/device.h>
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#include <linux/workqueue.h>
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#include <linux/kfifo.h>
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#include <linux/mutex.h>
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#include <linux/iio/iio.h>
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#include <linux/iio/buffer.h>
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#include <linux/iio/kfifo_buf.h>
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#include <linux/iio/buffer_impl.h>
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#include <linux/sched.h>
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#include <linux/poll.h>
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struct iio_kfifo {
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struct iio_buffer buffer;
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struct kfifo kf;
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struct mutex user_lock;
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int update_needed;
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};
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#define iio_to_kfifo(r) container_of(r, struct iio_kfifo, buffer)
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static inline int __iio_allocate_kfifo(struct iio_kfifo *buf,
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size_t bytes_per_datum, unsigned int length)
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{
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if ((length == 0) || (bytes_per_datum == 0))
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return -EINVAL;
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/*
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* Make sure we don't overflow an unsigned int after kfifo rounds up to
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* the next power of 2.
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*/
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if (roundup_pow_of_two(length) > UINT_MAX / bytes_per_datum)
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return -EINVAL;
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return __kfifo_alloc((struct __kfifo *)&buf->kf, length,
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bytes_per_datum, GFP_KERNEL);
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}
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static int iio_request_update_kfifo(struct iio_buffer *r)
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{
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int ret = 0;
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struct iio_kfifo *buf = iio_to_kfifo(r);
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mutex_lock(&buf->user_lock);
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if (buf->update_needed) {
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kfifo_free(&buf->kf);
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ret = __iio_allocate_kfifo(buf, buf->buffer.bytes_per_datum,
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buf->buffer.length);
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if (ret >= 0)
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buf->update_needed = false;
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} else {
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kfifo_reset_out(&buf->kf);
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}
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mutex_unlock(&buf->user_lock);
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return ret;
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}
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static int iio_mark_update_needed_kfifo(struct iio_buffer *r)
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{
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struct iio_kfifo *kf = iio_to_kfifo(r);
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kf->update_needed = true;
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return 0;
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}
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static int iio_set_bytes_per_datum_kfifo(struct iio_buffer *r, size_t bpd)
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{
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if (r->bytes_per_datum != bpd) {
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r->bytes_per_datum = bpd;
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iio_mark_update_needed_kfifo(r);
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}
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return 0;
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}
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static int iio_set_length_kfifo(struct iio_buffer *r, unsigned int length)
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{
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/* Avoid an invalid state */
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if (length < 2)
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length = 2;
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if (r->length != length) {
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r->length = length;
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iio_mark_update_needed_kfifo(r);
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}
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return 0;
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}
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static int iio_store_to_kfifo(struct iio_buffer *r,
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const void *data)
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{
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int ret;
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struct iio_kfifo *kf = iio_to_kfifo(r);
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ret = kfifo_in(&kf->kf, data, 1);
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if (ret != 1)
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return -EBUSY;
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return 0;
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}
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static int iio_read_kfifo(struct iio_buffer *r, size_t n, char __user *buf)
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{
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int ret, copied;
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struct iio_kfifo *kf = iio_to_kfifo(r);
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if (mutex_lock_interruptible(&kf->user_lock))
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return -ERESTARTSYS;
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if (!kfifo_initialized(&kf->kf) || n < kfifo_esize(&kf->kf))
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ret = -EINVAL;
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else
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ret = kfifo_to_user(&kf->kf, buf, n, &copied);
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mutex_unlock(&kf->user_lock);
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if (ret < 0)
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return ret;
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return copied;
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}
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static size_t iio_kfifo_buf_data_available(struct iio_buffer *r)
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{
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struct iio_kfifo *kf = iio_to_kfifo(r);
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size_t samples;
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mutex_lock(&kf->user_lock);
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samples = kfifo_len(&kf->kf);
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mutex_unlock(&kf->user_lock);
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return samples;
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}
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static void iio_kfifo_buffer_release(struct iio_buffer *buffer)
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{
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struct iio_kfifo *kf = iio_to_kfifo(buffer);
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mutex_destroy(&kf->user_lock);
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kfifo_free(&kf->kf);
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kfree(kf);
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}
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static const struct iio_buffer_access_funcs kfifo_access_funcs = {
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.store_to = &iio_store_to_kfifo,
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.read = &iio_read_kfifo,
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.data_available = iio_kfifo_buf_data_available,
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.request_update = &iio_request_update_kfifo,
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.set_bytes_per_datum = &iio_set_bytes_per_datum_kfifo,
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.set_length = &iio_set_length_kfifo,
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.release = &iio_kfifo_buffer_release,
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.modes = INDIO_BUFFER_SOFTWARE | INDIO_BUFFER_TRIGGERED,
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};
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struct iio_buffer *iio_kfifo_allocate(void)
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{
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struct iio_kfifo *kf;
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kf = kzalloc(sizeof(*kf), GFP_KERNEL);
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if (!kf)
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return NULL;
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kf->update_needed = true;
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iio_buffer_init(&kf->buffer);
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kf->buffer.access = &kfifo_access_funcs;
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kf->buffer.length = 2;
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mutex_init(&kf->user_lock);
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return &kf->buffer;
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}
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EXPORT_SYMBOL(iio_kfifo_allocate);
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void iio_kfifo_free(struct iio_buffer *r)
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{
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iio_buffer_put(r);
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}
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EXPORT_SYMBOL(iio_kfifo_free);
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static void devm_iio_kfifo_release(struct device *dev, void *res)
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{
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iio_kfifo_free(*(struct iio_buffer **)res);
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}
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/**
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* devm_iio_kfifo_allocate - Resource-managed iio_kfifo_allocate()
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* @dev: Device to allocate kfifo buffer for
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*
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* RETURNS:
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* Pointer to allocated iio_buffer on success, NULL on failure.
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*/
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static struct iio_buffer *devm_iio_kfifo_allocate(struct device *dev)
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{
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struct iio_buffer **ptr, *r;
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ptr = devres_alloc(devm_iio_kfifo_release, sizeof(*ptr), GFP_KERNEL);
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if (!ptr)
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return NULL;
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r = iio_kfifo_allocate();
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if (r) {
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*ptr = r;
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devres_add(dev, ptr);
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} else {
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devres_free(ptr);
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}
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return r;
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}
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/**
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* devm_iio_kfifo_buffer_setup_ext - Allocate a kfifo buffer & attach it to an IIO device
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* @dev: Device object to which to attach the life-time of this kfifo buffer
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* @indio_dev: The device the buffer should be attached to
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* @mode_flags: The mode flags for this buffer (INDIO_BUFFER_SOFTWARE and/or
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* INDIO_BUFFER_TRIGGERED).
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* @setup_ops: The setup_ops required to configure the HW part of the buffer (optional)
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* @buffer_attrs: Extra sysfs buffer attributes for this IIO buffer
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*
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* This function allocates a kfifo buffer via devm_iio_kfifo_allocate() and
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* attaches it to the IIO device via iio_device_attach_buffer().
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* This is meant to be a bit of a short-hand/helper function as there are a few
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* drivers that seem to do this.
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*/
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int devm_iio_kfifo_buffer_setup_ext(struct device *dev,
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struct iio_dev *indio_dev,
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int mode_flags,
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const struct iio_buffer_setup_ops *setup_ops,
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const struct attribute **buffer_attrs)
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{
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struct iio_buffer *buffer;
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if (!mode_flags)
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return -EINVAL;
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buffer = devm_iio_kfifo_allocate(dev);
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if (!buffer)
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return -ENOMEM;
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mode_flags &= kfifo_access_funcs.modes;
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indio_dev->modes |= mode_flags;
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indio_dev->setup_ops = setup_ops;
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buffer->attrs = buffer_attrs;
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return iio_device_attach_buffer(indio_dev, buffer);
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}
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EXPORT_SYMBOL_GPL(devm_iio_kfifo_buffer_setup_ext);
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MODULE_LICENSE("GPL");
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