299 lines
6.9 KiB
C
299 lines
6.9 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 size_t iio_kfifo_buf_space_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 avail;
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mutex_lock(&kf->user_lock);
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avail = kfifo_avail(&kf->kf);
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mutex_unlock(&kf->user_lock);
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return avail;
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}
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static int iio_kfifo_remove_from(struct iio_buffer *r, 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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if (kfifo_size(&kf->kf) < 1)
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return -EBUSY;
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ret = kfifo_out(&kf->kf, data, 1);
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if (ret != 1)
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return -EBUSY;
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wake_up_interruptible_poll(&r->pollq, EPOLLOUT | EPOLLWRNORM);
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return 0;
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}
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static int iio_kfifo_write(struct iio_buffer *r, size_t n,
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const char __user *buf)
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{
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struct iio_kfifo *kf = iio_to_kfifo(r);
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int ret, copied;
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mutex_lock(&kf->user_lock);
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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_from_user(&kf->kf, buf, n, &copied);
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mutex_unlock(&kf->user_lock);
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if (ret)
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return ret;
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return copied;
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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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.remove_from = &iio_kfifo_remove_from,
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.write = &iio_kfifo_write,
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.space_available = &iio_kfifo_buf_space_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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