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209 lines
4.5 KiB
209 lines
4.5 KiB
// 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_fifo_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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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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EXPORT_SYMBOL(devm_iio_kfifo_allocate); |
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MODULE_LICENSE("GPL");
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