| 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_ring_buffer ring; |
| 13 | struct kfifo kf; |
| 14 | int use_count; |
| 15 | int update_needed; |
| 16 | struct mutex use_lock; |
| 17 | }; |
| 18 | |
| 19 | #define iio_to_kfifo(r) container_of(r, struct iio_kfifo, ring) |
| 20 | |
| 21 | static inline int __iio_allocate_kfifo(struct iio_kfifo *buf, |
| 22 | int bytes_per_datum, int length) |
| 23 | { |
| 24 | if ((length == 0) || (bytes_per_datum == 0)) |
| 25 | return -EINVAL; |
| 26 | |
| 27 | __iio_update_ring_buffer(&buf->ring, bytes_per_datum, length); |
| 28 | return kfifo_alloc(&buf->kf, bytes_per_datum*length, GFP_KERNEL); |
| 29 | } |
| 30 | |
| 31 | static int iio_request_update_kfifo(struct iio_ring_buffer *r) |
| 32 | { |
| 33 | int ret = 0; |
| 34 | struct iio_kfifo *buf = iio_to_kfifo(r); |
| 35 | |
| 36 | mutex_lock(&buf->use_lock); |
| 37 | if (!buf->update_needed) |
| 38 | goto error_ret; |
| 39 | if (buf->use_count) { |
| 40 | ret = -EAGAIN; |
| 41 | goto error_ret; |
| 42 | } |
| 43 | kfifo_free(&buf->kf); |
| 44 | ret = __iio_allocate_kfifo(buf, buf->ring.bytes_per_datum, |
| 45 | buf->ring.length); |
| 46 | error_ret: |
| 47 | mutex_unlock(&buf->use_lock); |
| 48 | return ret; |
| 49 | } |
| 50 | |
| 51 | static void iio_mark_kfifo_in_use(struct iio_ring_buffer *r) |
| 52 | { |
| 53 | struct iio_kfifo *buf = iio_to_kfifo(r); |
| 54 | mutex_lock(&buf->use_lock); |
| 55 | buf->use_count++; |
| 56 | mutex_unlock(&buf->use_lock); |
| 57 | } |
| 58 | |
| 59 | static void iio_unmark_kfifo_in_use(struct iio_ring_buffer *r) |
| 60 | { |
| 61 | struct iio_kfifo *buf = iio_to_kfifo(r); |
| 62 | mutex_lock(&buf->use_lock); |
| 63 | buf->use_count--; |
| 64 | mutex_unlock(&buf->use_lock); |
| 65 | } |
| 66 | |
| 67 | static int iio_get_length_kfifo(struct iio_ring_buffer *r) |
| 68 | { |
| 69 | return r->length; |
| 70 | } |
| 71 | |
| 72 | static inline void __iio_init_kfifo(struct iio_kfifo *kf) |
| 73 | { |
| 74 | mutex_init(&kf->use_lock); |
| 75 | } |
| 76 | |
| 77 | static IIO_RING_ENABLE_ATTR; |
| 78 | static IIO_RING_BYTES_PER_DATUM_ATTR; |
| 79 | static IIO_RING_LENGTH_ATTR; |
| 80 | |
| 81 | static struct attribute *iio_kfifo_attributes[] = { |
| 82 | &dev_attr_length.attr, |
| 83 | &dev_attr_bytes_per_datum.attr, |
| 84 | &dev_attr_enable.attr, |
| 85 | NULL, |
| 86 | }; |
| 87 | |
| 88 | static struct attribute_group iio_kfifo_attribute_group = { |
| 89 | .attrs = iio_kfifo_attributes, |
| 90 | .name = "buffer", |
| 91 | }; |
| 92 | |
| 93 | struct iio_ring_buffer *iio_kfifo_allocate(struct iio_dev *indio_dev) |
| 94 | { |
| 95 | struct iio_kfifo *kf; |
| 96 | |
| 97 | kf = kzalloc(sizeof *kf, GFP_KERNEL); |
| 98 | if (!kf) |
| 99 | return NULL; |
| 100 | kf->update_needed = true; |
| 101 | iio_ring_buffer_init(&kf->ring, indio_dev); |
| 102 | kf->ring.attrs = &iio_kfifo_attribute_group; |
| 103 | __iio_init_kfifo(kf); |
| 104 | |
| 105 | return &kf->ring; |
| 106 | } |
| 107 | EXPORT_SYMBOL(iio_kfifo_allocate); |
| 108 | |
| 109 | static int iio_get_bytes_per_datum_kfifo(struct iio_ring_buffer *r) |
| 110 | { |
| 111 | return r->bytes_per_datum; |
| 112 | } |
| 113 | |
| 114 | static int iio_set_bytes_per_datum_kfifo(struct iio_ring_buffer *r, size_t bpd) |
| 115 | { |
| 116 | if (r->bytes_per_datum != bpd) { |
| 117 | r->bytes_per_datum = bpd; |
| 118 | if (r->access->mark_param_change) |
| 119 | r->access->mark_param_change(r); |
| 120 | } |
| 121 | return 0; |
| 122 | } |
| 123 | |
| 124 | static int iio_mark_update_needed_kfifo(struct iio_ring_buffer *r) |
| 125 | { |
| 126 | struct iio_kfifo *kf = iio_to_kfifo(r); |
| 127 | kf->update_needed = true; |
| 128 | return 0; |
| 129 | } |
| 130 | |
| 131 | static int iio_set_length_kfifo(struct iio_ring_buffer *r, int length) |
| 132 | { |
| 133 | if (r->length != length) { |
| 134 | r->length = length; |
| 135 | if (r->access->mark_param_change) |
| 136 | r->access->mark_param_change(r); |
| 137 | } |
| 138 | return 0; |
| 139 | } |
| 140 | |
| 141 | void iio_kfifo_free(struct iio_ring_buffer *r) |
| 142 | { |
| 143 | kfree(iio_to_kfifo(r)); |
| 144 | } |
| 145 | EXPORT_SYMBOL(iio_kfifo_free); |
| 146 | |
| 147 | static int iio_store_to_kfifo(struct iio_ring_buffer *r, |
| 148 | u8 *data, |
| 149 | s64 timestamp) |
| 150 | { |
| 151 | int ret; |
| 152 | struct iio_kfifo *kf = iio_to_kfifo(r); |
| 153 | u8 *datal = kmalloc(r->bytes_per_datum, GFP_KERNEL); |
| 154 | memcpy(datal, data, r->bytes_per_datum - sizeof(timestamp)); |
| 155 | memcpy(datal + r->bytes_per_datum - sizeof(timestamp), |
| 156 | ×tamp, sizeof(timestamp)); |
| 157 | ret = kfifo_in(&kf->kf, data, r->bytes_per_datum); |
| 158 | if (ret != r->bytes_per_datum) { |
| 159 | kfree(datal); |
| 160 | return -EBUSY; |
| 161 | } |
| 162 | kfree(datal); |
| 163 | return 0; |
| 164 | } |
| 165 | |
| 166 | static int iio_read_first_n_kfifo(struct iio_ring_buffer *r, |
| 167 | size_t n, char __user *buf) |
| 168 | { |
| 169 | int ret, copied; |
| 170 | struct iio_kfifo *kf = iio_to_kfifo(r); |
| 171 | |
| 172 | ret = kfifo_to_user(&kf->kf, buf, r->bytes_per_datum*n, &copied); |
| 173 | |
| 174 | return copied; |
| 175 | } |
| 176 | |
| 177 | const struct iio_ring_access_funcs kfifo_access_funcs = { |
| 178 | .mark_in_use = &iio_mark_kfifo_in_use, |
| 179 | .unmark_in_use = &iio_unmark_kfifo_in_use, |
| 180 | .store_to = &iio_store_to_kfifo, |
| 181 | .read_first_n = &iio_read_first_n_kfifo, |
| 182 | .mark_param_change = &iio_mark_update_needed_kfifo, |
| 183 | .request_update = &iio_request_update_kfifo, |
| 184 | .get_bytes_per_datum = &iio_get_bytes_per_datum_kfifo, |
| 185 | .set_bytes_per_datum = &iio_set_bytes_per_datum_kfifo, |
| 186 | .get_length = &iio_get_length_kfifo, |
| 187 | .set_length = &iio_set_length_kfifo, |
| 188 | }; |
| 189 | EXPORT_SYMBOL(kfifo_access_funcs); |
| 190 | |
| 191 | MODULE_LICENSE("GPL"); |