| 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 | #include <linux/iio/kfifo_buf.h> |
| 9 | #include <linux/sched.h> |
| 10 | #include <linux/poll.h> |
| 11 | |
| 12 | struct iio_kfifo { |
| 13 | struct iio_buffer buffer; |
| 14 | struct kfifo kf; |
| 15 | struct mutex user_lock; |
| 16 | int update_needed; |
| 17 | }; |
| 18 | |
| 19 | #define iio_to_kfifo(r) container_of(r, struct iio_kfifo, buffer) |
| 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 | return __kfifo_alloc((struct __kfifo *)&buf->kf, length, |
| 28 | bytes_per_datum, GFP_KERNEL); |
| 29 | } |
| 30 | |
| 31 | static int iio_request_update_kfifo(struct iio_buffer *r) |
| 32 | { |
| 33 | int ret = 0; |
| 34 | struct iio_kfifo *buf = iio_to_kfifo(r); |
| 35 | |
| 36 | mutex_lock(&buf->user_lock); |
| 37 | if (buf->update_needed) { |
| 38 | kfifo_free(&buf->kf); |
| 39 | ret = __iio_allocate_kfifo(buf, buf->buffer.bytes_per_datum, |
| 40 | buf->buffer.length); |
| 41 | if (ret >= 0) |
| 42 | buf->update_needed = false; |
| 43 | } else { |
| 44 | kfifo_reset_out(&buf->kf); |
| 45 | } |
| 46 | mutex_unlock(&buf->user_lock); |
| 47 | |
| 48 | return ret; |
| 49 | } |
| 50 | |
| 51 | static int iio_mark_update_needed_kfifo(struct iio_buffer *r) |
| 52 | { |
| 53 | struct iio_kfifo *kf = iio_to_kfifo(r); |
| 54 | kf->update_needed = true; |
| 55 | return 0; |
| 56 | } |
| 57 | |
| 58 | static int iio_set_bytes_per_datum_kfifo(struct iio_buffer *r, size_t bpd) |
| 59 | { |
| 60 | if (r->bytes_per_datum != bpd) { |
| 61 | r->bytes_per_datum = bpd; |
| 62 | iio_mark_update_needed_kfifo(r); |
| 63 | } |
| 64 | return 0; |
| 65 | } |
| 66 | |
| 67 | static int iio_set_length_kfifo(struct iio_buffer *r, int length) |
| 68 | { |
| 69 | /* Avoid an invalid state */ |
| 70 | if (length < 2) |
| 71 | length = 2; |
| 72 | if (r->length != length) { |
| 73 | r->length = length; |
| 74 | iio_mark_update_needed_kfifo(r); |
| 75 | } |
| 76 | return 0; |
| 77 | } |
| 78 | |
| 79 | static int iio_store_to_kfifo(struct iio_buffer *r, |
| 80 | const void *data) |
| 81 | { |
| 82 | int ret; |
| 83 | struct iio_kfifo *kf = iio_to_kfifo(r); |
| 84 | ret = kfifo_in(&kf->kf, data, 1); |
| 85 | if (ret != 1) |
| 86 | return -EBUSY; |
| 87 | return 0; |
| 88 | } |
| 89 | |
| 90 | static int iio_read_first_n_kfifo(struct iio_buffer *r, |
| 91 | size_t n, char __user *buf) |
| 92 | { |
| 93 | int ret, copied; |
| 94 | struct iio_kfifo *kf = iio_to_kfifo(r); |
| 95 | |
| 96 | if (mutex_lock_interruptible(&kf->user_lock)) |
| 97 | return -ERESTARTSYS; |
| 98 | |
| 99 | if (!kfifo_initialized(&kf->kf) || n < kfifo_esize(&kf->kf)) |
| 100 | ret = -EINVAL; |
| 101 | else |
| 102 | ret = kfifo_to_user(&kf->kf, buf, n, &copied); |
| 103 | mutex_unlock(&kf->user_lock); |
| 104 | if (ret < 0) |
| 105 | return ret; |
| 106 | |
| 107 | return copied; |
| 108 | } |
| 109 | |
| 110 | static size_t iio_kfifo_buf_data_available(struct iio_buffer *r) |
| 111 | { |
| 112 | struct iio_kfifo *kf = iio_to_kfifo(r); |
| 113 | size_t samples; |
| 114 | |
| 115 | mutex_lock(&kf->user_lock); |
| 116 | samples = kfifo_len(&kf->kf); |
| 117 | mutex_unlock(&kf->user_lock); |
| 118 | |
| 119 | return samples; |
| 120 | } |
| 121 | |
| 122 | static void iio_kfifo_buffer_release(struct iio_buffer *buffer) |
| 123 | { |
| 124 | struct iio_kfifo *kf = iio_to_kfifo(buffer); |
| 125 | |
| 126 | mutex_destroy(&kf->user_lock); |
| 127 | kfifo_free(&kf->kf); |
| 128 | kfree(kf); |
| 129 | } |
| 130 | |
| 131 | static const struct iio_buffer_access_funcs kfifo_access_funcs = { |
| 132 | .store_to = &iio_store_to_kfifo, |
| 133 | .read_first_n = &iio_read_first_n_kfifo, |
| 134 | .data_available = iio_kfifo_buf_data_available, |
| 135 | .request_update = &iio_request_update_kfifo, |
| 136 | .set_bytes_per_datum = &iio_set_bytes_per_datum_kfifo, |
| 137 | .set_length = &iio_set_length_kfifo, |
| 138 | .release = &iio_kfifo_buffer_release, |
| 139 | |
| 140 | .modes = INDIO_BUFFER_SOFTWARE | INDIO_BUFFER_TRIGGERED, |
| 141 | }; |
| 142 | |
| 143 | struct iio_buffer *iio_kfifo_allocate(void) |
| 144 | { |
| 145 | struct iio_kfifo *kf; |
| 146 | |
| 147 | kf = kzalloc(sizeof(*kf), GFP_KERNEL); |
| 148 | if (!kf) |
| 149 | return NULL; |
| 150 | |
| 151 | kf->update_needed = true; |
| 152 | iio_buffer_init(&kf->buffer); |
| 153 | kf->buffer.access = &kfifo_access_funcs; |
| 154 | kf->buffer.length = 2; |
| 155 | mutex_init(&kf->user_lock); |
| 156 | |
| 157 | return &kf->buffer; |
| 158 | } |
| 159 | EXPORT_SYMBOL(iio_kfifo_allocate); |
| 160 | |
| 161 | void iio_kfifo_free(struct iio_buffer *r) |
| 162 | { |
| 163 | iio_buffer_put(r); |
| 164 | } |
| 165 | EXPORT_SYMBOL(iio_kfifo_free); |
| 166 | |
| 167 | static void devm_iio_kfifo_release(struct device *dev, void *res) |
| 168 | { |
| 169 | iio_kfifo_free(*(struct iio_buffer **)res); |
| 170 | } |
| 171 | |
| 172 | static int devm_iio_kfifo_match(struct device *dev, void *res, void *data) |
| 173 | { |
| 174 | struct iio_buffer **r = res; |
| 175 | |
| 176 | if (WARN_ON(!r || !*r)) |
| 177 | return 0; |
| 178 | |
| 179 | return *r == data; |
| 180 | } |
| 181 | |
| 182 | /** |
| 183 | * devm_iio_fifo_allocate - Resource-managed iio_kfifo_allocate() |
| 184 | * @dev: Device to allocate kfifo buffer for |
| 185 | * |
| 186 | * RETURNS: |
| 187 | * Pointer to allocated iio_buffer on success, NULL on failure. |
| 188 | */ |
| 189 | struct iio_buffer *devm_iio_kfifo_allocate(struct device *dev) |
| 190 | { |
| 191 | struct iio_buffer **ptr, *r; |
| 192 | |
| 193 | ptr = devres_alloc(devm_iio_kfifo_release, sizeof(*ptr), GFP_KERNEL); |
| 194 | if (!ptr) |
| 195 | return NULL; |
| 196 | |
| 197 | r = iio_kfifo_allocate(); |
| 198 | if (r) { |
| 199 | *ptr = r; |
| 200 | devres_add(dev, ptr); |
| 201 | } else { |
| 202 | devres_free(ptr); |
| 203 | } |
| 204 | |
| 205 | return r; |
| 206 | } |
| 207 | EXPORT_SYMBOL(devm_iio_kfifo_allocate); |
| 208 | |
| 209 | /** |
| 210 | * devm_iio_fifo_free - Resource-managed iio_kfifo_free() |
| 211 | * @dev: Device the buffer belongs to |
| 212 | * @r: The buffer associated with the device |
| 213 | */ |
| 214 | void devm_iio_kfifo_free(struct device *dev, struct iio_buffer *r) |
| 215 | { |
| 216 | WARN_ON(devres_release(dev, devm_iio_kfifo_release, |
| 217 | devm_iio_kfifo_match, r)); |
| 218 | } |
| 219 | EXPORT_SYMBOL(devm_iio_kfifo_free); |
| 220 | |
| 221 | MODULE_LICENSE("GPL"); |