drivers/staging/iio/kfifo_buf.c

   1 #include <linux/slab.h>
   2 #include <linux/kernel.h>
   3 #include <linux/module.h>
   4 #include <linux/device.h>
   5 #include <linux/workqueue.h>
   6 #include <linux/kfifo.h>
   7 #include <linux/mutex.h>
   8
   9 #include "kfifo_buf.h"
  10
  11 struct iio_kfifo {
  12         struct iio_buffer buffer;
  13         struct kfifo kf;
  14         int update_needed;
  15 };
  16
  17 #define iio_to_kfifo(r) container_of(r, struct iio_kfifo, buffer)
  18
  19 static inline int __iio_allocate_kfifo(struct iio_kfifo *buf,
  20                                 int bytes_per_datum, int length)
  21 {
  22         if ((length == 0) || (bytes_per_datum == 0))
  23                 return -EINVAL;
  24
  25         __iio_update_buffer(&buf->buffer, bytes_per_datum, length);
  26         return kfifo_alloc(&buf->kf, bytes_per_datum*length, GFP_KERNEL);
  27 }
  28
  29 static int iio_request_update_kfifo(struct iio_buffer *r)
  30 {
  31         int ret = 0;
  32         struct iio_kfifo *buf = iio_to_kfifo(r);
  33
  34         if (!buf->update_needed)
  35                 goto error_ret;
  36         kfifo_free(&buf->kf);
  37         ret = __iio_allocate_kfifo(buf, buf->buffer.bytes_per_datum,
  38                                    buf->buffer.length);
  39 error_ret:
  40         return ret;
  41 }
  42
  43 static int iio_get_length_kfifo(struct iio_buffer *r)
  44 {
  45         return r->length;
  46 }
  47
  48 static IIO_BUFFER_ENABLE_ATTR;
  49 static IIO_BUFFER_LENGTH_ATTR;
  50
  51 static struct attribute *iio_kfifo_attributes[] = {
  52         &dev_attr_length.attr,
  53         &dev_attr_enable.attr,
  54         NULL,
  55 };
  56
  57 static struct attribute_group iio_kfifo_attribute_group = {
  58         .attrs = iio_kfifo_attributes,
  59         .name = "buffer",
  60 };
  61
  62 struct iio_buffer *iio_kfifo_allocate(struct iio_dev *indio_dev)
  63 {
  64         struct iio_kfifo *kf;
  65
  66         kf = kzalloc(sizeof *kf, GFP_KERNEL);
  67         if (!kf)
  68                 return NULL;
  69         kf->update_needed = true;
  70         iio_buffer_init(&kf->buffer);
  71         kf->buffer.attrs = &iio_kfifo_attribute_group;
  72
  73         return &kf->buffer;
  74 }
  75 EXPORT_SYMBOL(iio_kfifo_allocate);
  76
  77 static int iio_get_bytes_per_datum_kfifo(struct iio_buffer *r)
  78 {
  79         return r->bytes_per_datum;
  80 }
  81
  82 static int iio_mark_update_needed_kfifo(struct iio_buffer *r)
  83 {
  84         struct iio_kfifo *kf = iio_to_kfifo(r);
  85         kf->update_needed = true;
  86         return 0;
  87 }
  88
  89 static int iio_set_bytes_per_datum_kfifo(struct iio_buffer *r, size_t bpd)
  90 {
  91         if (r->bytes_per_datum != bpd) {
  92                 r->bytes_per_datum = bpd;
  93                 iio_mark_update_needed_kfifo(r);
  94         }
  95         return 0;
  96 }
  97
  98 static int iio_set_length_kfifo(struct iio_buffer *r, int length)
  99 {
 100         if (r->length != length) {
 101                 r->length = length;
 102                 iio_mark_update_needed_kfifo(r);
 103         }
 104         return 0;
 105 }
 106
 107 void iio_kfifo_free(struct iio_buffer *r)
 108 {
 109         kfree(iio_to_kfifo(r));
 110 }
 111 EXPORT_SYMBOL(iio_kfifo_free);
 112
 113 static int iio_store_to_kfifo(struct iio_buffer *r,
 114                               u8 *data,
 115                               s64 timestamp)
 116 {
 117         int ret;
 118         struct iio_kfifo *kf = iio_to_kfifo(r);
 119         ret = kfifo_in(&kf->kf, data, r->bytes_per_datum);
 120         if (ret != r->bytes_per_datum)
 121                 return -EBUSY;
 122         return 0;
 123 }
 124
 125 static int iio_read_first_n_kfifo(struct iio_buffer *r,
 126                            size_t n, char __user *buf)
 127 {
 128         int ret, copied;
 129         struct iio_kfifo *kf = iio_to_kfifo(r);
 130
 131         if (n < r->bytes_per_datum)
 132                 return -EINVAL;
 133
 134         n = rounddown(n, r->bytes_per_datum);
 135         ret = kfifo_to_user(&kf->kf, buf, n, &copied);
 136
 137         return copied;
 138 }
 139
 140 const struct iio_buffer_access_funcs kfifo_access_funcs = {
 141         .store_to = &iio_store_to_kfifo,
 142         .read_first_n = &iio_read_first_n_kfifo,
 143         .request_update = &iio_request_update_kfifo,
 144         .get_bytes_per_datum = &iio_get_bytes_per_datum_kfifo,
 145         .set_bytes_per_datum = &iio_set_bytes_per_datum_kfifo,
 146         .get_length = &iio_get_length_kfifo,
 147         .set_length = &iio_set_length_kfifo,
 148 };
 149 EXPORT_SYMBOL(kfifo_access_funcs);
 150
 151 MODULE_LICENSE("GPL");