| // SPDX-License-Identifier: GPL-2.0-only |
| #include <linux/slab.h> |
| #include <linux/kernel.h> |
| #include <linux/module.h> |
| #include <linux/device.h> |
| #include <linux/workqueue.h> |
| #include <linux/kfifo.h> |
| #include <linux/mutex.h> |
| #include <linux/iio/iio.h> |
| #include <linux/iio/buffer.h> |
| #include <linux/iio/kfifo_buf.h> |
| #include <linux/iio/buffer_impl.h> |
| #include <linux/sched.h> |
| #include <linux/poll.h> |
| |
| struct iio_kfifo { |
| struct iio_buffer buffer; |
| struct kfifo kf; |
| struct mutex user_lock; |
| int update_needed; |
| }; |
| |
| #define iio_to_kfifo(r) container_of(r, struct iio_kfifo, buffer) |
| |
| static inline int __iio_allocate_kfifo(struct iio_kfifo *buf, |
| size_t bytes_per_datum, unsigned int length) |
| { |
| if ((length == 0) || (bytes_per_datum == 0)) |
| return -EINVAL; |
| |
| /* |
| * Make sure we don't overflow an unsigned int after kfifo rounds up to |
| * the next power of 2. |
| */ |
| if (roundup_pow_of_two(length) > UINT_MAX / bytes_per_datum) |
| return -EINVAL; |
| |
| return __kfifo_alloc((struct __kfifo *)&buf->kf, length, |
| bytes_per_datum, GFP_KERNEL); |
| } |
| |
| static int iio_request_update_kfifo(struct iio_buffer *r) |
| { |
| int ret = 0; |
| struct iio_kfifo *buf = iio_to_kfifo(r); |
| |
| mutex_lock(&buf->user_lock); |
| if (buf->update_needed) { |
| kfifo_free(&buf->kf); |
| ret = __iio_allocate_kfifo(buf, buf->buffer.bytes_per_datum, |
| buf->buffer.length); |
| if (ret >= 0) |
| buf->update_needed = false; |
| } else { |
| kfifo_reset_out(&buf->kf); |
| } |
| mutex_unlock(&buf->user_lock); |
| |
| return ret; |
| } |
| |
| static int iio_mark_update_needed_kfifo(struct iio_buffer *r) |
| { |
| struct iio_kfifo *kf = iio_to_kfifo(r); |
| kf->update_needed = true; |
| return 0; |
| } |
| |
| static int iio_set_bytes_per_datum_kfifo(struct iio_buffer *r, size_t bpd) |
| { |
| if (r->bytes_per_datum != bpd) { |
| r->bytes_per_datum = bpd; |
| iio_mark_update_needed_kfifo(r); |
| } |
| return 0; |
| } |
| |
| static int iio_set_length_kfifo(struct iio_buffer *r, unsigned int length) |
| { |
| /* Avoid an invalid state */ |
| if (length < 2) |
| length = 2; |
| if (r->length != length) { |
| r->length = length; |
| iio_mark_update_needed_kfifo(r); |
| } |
| return 0; |
| } |
| |
| static int iio_store_to_kfifo(struct iio_buffer *r, |
| const void *data) |
| { |
| int ret; |
| struct iio_kfifo *kf = iio_to_kfifo(r); |
| ret = kfifo_in(&kf->kf, data, 1); |
| if (ret != 1) |
| return -EBUSY; |
| return 0; |
| } |
| |
| static int iio_read_kfifo(struct iio_buffer *r, size_t n, char __user *buf) |
| { |
| int ret, copied; |
| struct iio_kfifo *kf = iio_to_kfifo(r); |
| |
| if (mutex_lock_interruptible(&kf->user_lock)) |
| return -ERESTARTSYS; |
| |
| if (!kfifo_initialized(&kf->kf) || n < kfifo_esize(&kf->kf)) |
| ret = -EINVAL; |
| else |
| ret = kfifo_to_user(&kf->kf, buf, n, &copied); |
| mutex_unlock(&kf->user_lock); |
| if (ret < 0) |
| return ret; |
| |
| return copied; |
| } |
| |
| static size_t iio_kfifo_buf_data_available(struct iio_buffer *r) |
| { |
| struct iio_kfifo *kf = iio_to_kfifo(r); |
| size_t samples; |
| |
| mutex_lock(&kf->user_lock); |
| samples = kfifo_len(&kf->kf); |
| mutex_unlock(&kf->user_lock); |
| |
| return samples; |
| } |
| |
| static void iio_kfifo_buffer_release(struct iio_buffer *buffer) |
| { |
| struct iio_kfifo *kf = iio_to_kfifo(buffer); |
| |
| mutex_destroy(&kf->user_lock); |
| kfifo_free(&kf->kf); |
| kfree(kf); |
| } |
| |
| static const struct iio_buffer_access_funcs kfifo_access_funcs = { |
| .store_to = &iio_store_to_kfifo, |
| .read = &iio_read_kfifo, |
| .data_available = iio_kfifo_buf_data_available, |
| .request_update = &iio_request_update_kfifo, |
| .set_bytes_per_datum = &iio_set_bytes_per_datum_kfifo, |
| .set_length = &iio_set_length_kfifo, |
| .release = &iio_kfifo_buffer_release, |
| |
| .modes = INDIO_BUFFER_SOFTWARE | INDIO_BUFFER_TRIGGERED, |
| }; |
| |
| struct iio_buffer *iio_kfifo_allocate(void) |
| { |
| struct iio_kfifo *kf; |
| |
| kf = kzalloc(sizeof(*kf), GFP_KERNEL); |
| if (!kf) |
| return NULL; |
| |
| kf->update_needed = true; |
| iio_buffer_init(&kf->buffer); |
| kf->buffer.access = &kfifo_access_funcs; |
| kf->buffer.length = 2; |
| mutex_init(&kf->user_lock); |
| |
| return &kf->buffer; |
| } |
| EXPORT_SYMBOL(iio_kfifo_allocate); |
| |
| void iio_kfifo_free(struct iio_buffer *r) |
| { |
| iio_buffer_put(r); |
| } |
| EXPORT_SYMBOL(iio_kfifo_free); |
| |
| static void devm_iio_kfifo_release(struct device *dev, void *res) |
| { |
| iio_kfifo_free(*(struct iio_buffer **)res); |
| } |
| |
| static int devm_iio_kfifo_match(struct device *dev, void *res, void *data) |
| { |
| struct iio_buffer **r = res; |
| |
| if (WARN_ON(!r || !*r)) |
| return 0; |
| |
| return *r == data; |
| } |
| |
| /** |
| * devm_iio_fifo_allocate - Resource-managed iio_kfifo_allocate() |
| * @dev: Device to allocate kfifo buffer for |
| * |
| * RETURNS: |
| * Pointer to allocated iio_buffer on success, NULL on failure. |
| */ |
| struct iio_buffer *devm_iio_kfifo_allocate(struct device *dev) |
| { |
| struct iio_buffer **ptr, *r; |
| |
| ptr = devres_alloc(devm_iio_kfifo_release, sizeof(*ptr), GFP_KERNEL); |
| if (!ptr) |
| return NULL; |
| |
| r = iio_kfifo_allocate(); |
| if (r) { |
| *ptr = r; |
| devres_add(dev, ptr); |
| } else { |
| devres_free(ptr); |
| } |
| |
| return r; |
| } |
| EXPORT_SYMBOL(devm_iio_kfifo_allocate); |
| |
| /** |
| * devm_iio_fifo_free - Resource-managed iio_kfifo_free() |
| * @dev: Device the buffer belongs to |
| * @r: The buffer associated with the device |
| */ |
| void devm_iio_kfifo_free(struct device *dev, struct iio_buffer *r) |
| { |
| WARN_ON(devres_release(dev, devm_iio_kfifo_release, |
| devm_iio_kfifo_match, r)); |
| } |
| EXPORT_SYMBOL(devm_iio_kfifo_free); |
| |
| MODULE_LICENSE("GPL"); |