#include #include #include #include #include #include #include #include #include #include struct iio_kfifo { struct iio_buffer buffer; struct kfifo kf; 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, int bytes_per_datum, int length) { if ((length == 0) || (bytes_per_datum == 0)) 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); if (!buf->update_needed) goto error_ret; kfifo_free(&buf->kf); ret = __iio_allocate_kfifo(buf, buf->buffer.bytes_per_datum, buf->buffer.length); r->stufftoread = false; error_ret: return ret; } static int iio_get_length_kfifo(struct iio_buffer *r) { return r->length; } static IIO_BUFFER_ENABLE_ATTR; static IIO_BUFFER_LENGTH_ATTR; static struct attribute *iio_kfifo_attributes[] = { &dev_attr_length.attr, &dev_attr_enable.attr, NULL, }; static struct attribute_group iio_kfifo_attribute_group = { .attrs = iio_kfifo_attributes, .name = "buffer", }; static int iio_get_bytes_per_datum_kfifo(struct iio_buffer *r) { return r->bytes_per_datum; } 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, 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; r->stufftoread = true; wake_up_interruptible_poll(&r->pollq, POLLIN | POLLRDNORM); return 0; } static int iio_read_first_n_kfifo(struct iio_buffer *r, size_t n, char __user *buf) { int ret, copied; struct iio_kfifo *kf = iio_to_kfifo(r); if (n < r->bytes_per_datum || r->bytes_per_datum == 0) return -EINVAL; ret = kfifo_to_user(&kf->kf, buf, n, &copied); if (ret < 0) return ret; if (kfifo_is_empty(&kf->kf)) r->stufftoread = false; /* verify it is still empty to avoid race */ if (!kfifo_is_empty(&kf->kf)) r->stufftoread = true; return copied; } static void iio_kfifo_buffer_release(struct iio_buffer *buffer) { kfree(iio_to_kfifo(buffer)); } static const struct iio_buffer_access_funcs kfifo_access_funcs = { .store_to = &iio_store_to_kfifo, .read_first_n = &iio_read_first_n_kfifo, .request_update = &iio_request_update_kfifo, .get_bytes_per_datum = &iio_get_bytes_per_datum_kfifo, .set_bytes_per_datum = &iio_set_bytes_per_datum_kfifo, .get_length = &iio_get_length_kfifo, .set_length = &iio_set_length_kfifo, .release = &iio_kfifo_buffer_release, }; struct iio_buffer *iio_kfifo_allocate(struct iio_dev *indio_dev) { 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.attrs = &iio_kfifo_attribute_group; kf->buffer.access = &kfifo_access_funcs; kf->buffer.length = 2; 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); MODULE_LICENSE("GPL");