Commit | Line | Data |
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b174baf4 JC |
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> | |
06458e27 | 8 | #include <linux/iio/kfifo_buf.h> |
7c388ec1 | 9 | #include <linux/sched.h> |
623c334c | 10 | #include <linux/poll.h> |
b174baf4 | 11 | |
a710cc77 | 12 | struct iio_kfifo { |
14555b14 | 13 | struct iio_buffer buffer; |
a710cc77 | 14 | struct kfifo kf; |
0894d80d | 15 | struct mutex user_lock; |
a710cc77 | 16 | int update_needed; |
a710cc77 JC |
17 | }; |
18 | ||
14555b14 | 19 | #define iio_to_kfifo(r) container_of(r, struct iio_kfifo, buffer) |
5565a450 | 20 | |
b174baf4 JC |
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 | ||
c559afbf JC |
27 | return __kfifo_alloc((struct __kfifo *)&buf->kf, length, |
28 | bytes_per_datum, GFP_KERNEL); | |
b174baf4 JC |
29 | } |
30 | ||
14555b14 | 31 | static int iio_request_update_kfifo(struct iio_buffer *r) |
b174baf4 JC |
32 | { |
33 | int ret = 0; | |
34 | struct iio_kfifo *buf = iio_to_kfifo(r); | |
35 | ||
0894d80d | 36 | mutex_lock(&buf->user_lock); |
5b78e513 LPC |
37 | if (buf->update_needed) { |
38 | kfifo_free(&buf->kf); | |
39 | ret = __iio_allocate_kfifo(buf, buf->buffer.bytes_per_datum, | |
14555b14 | 40 | buf->buffer.length); |
cb6fbfa1 | 41 | buf->update_needed = false; |
5b78e513 LPC |
42 | } else { |
43 | kfifo_reset_out(&buf->kf); | |
44 | } | |
7c388ec1 | 45 | r->stufftoread = false; |
0894d80d | 46 | mutex_unlock(&buf->user_lock); |
5b78e513 | 47 | |
b174baf4 JC |
48 | return ret; |
49 | } | |
b174baf4 | 50 | |
14555b14 | 51 | static int iio_get_length_kfifo(struct iio_buffer *r) |
b174baf4 JC |
52 | { |
53 | return r->length; | |
54 | } | |
b174baf4 | 55 | |
14555b14 | 56 | static IIO_BUFFER_ENABLE_ATTR; |
14555b14 | 57 | static IIO_BUFFER_LENGTH_ATTR; |
b174baf4 JC |
58 | |
59 | static struct attribute *iio_kfifo_attributes[] = { | |
60 | &dev_attr_length.attr, | |
b174baf4 JC |
61 | &dev_attr_enable.attr, |
62 | NULL, | |
63 | }; | |
64 | ||
65 | static struct attribute_group iio_kfifo_attribute_group = { | |
66 | .attrs = iio_kfifo_attributes, | |
1aa04278 | 67 | .name = "buffer", |
b174baf4 JC |
68 | }; |
69 | ||
14555b14 | 70 | static int iio_get_bytes_per_datum_kfifo(struct iio_buffer *r) |
b174baf4 JC |
71 | { |
72 | return r->bytes_per_datum; | |
73 | } | |
b174baf4 | 74 | |
869871b5 | 75 | static int iio_mark_update_needed_kfifo(struct iio_buffer *r) |
b174baf4 | 76 | { |
869871b5 LPC |
77 | struct iio_kfifo *kf = iio_to_kfifo(r); |
78 | kf->update_needed = true; | |
b174baf4 JC |
79 | return 0; |
80 | } | |
b174baf4 | 81 | |
869871b5 | 82 | static int iio_set_bytes_per_datum_kfifo(struct iio_buffer *r, size_t bpd) |
b174baf4 | 83 | { |
869871b5 LPC |
84 | if (r->bytes_per_datum != bpd) { |
85 | r->bytes_per_datum = bpd; | |
86 | iio_mark_update_needed_kfifo(r); | |
87 | } | |
b174baf4 JC |
88 | return 0; |
89 | } | |
b174baf4 | 90 | |
14555b14 | 91 | static int iio_set_length_kfifo(struct iio_buffer *r, int length) |
b174baf4 | 92 | { |
7c388ec1 JC |
93 | /* Avoid an invalid state */ |
94 | if (length < 2) | |
95 | length = 2; | |
b174baf4 JC |
96 | if (r->length != length) { |
97 | r->length = length; | |
869871b5 | 98 | iio_mark_update_needed_kfifo(r); |
b174baf4 JC |
99 | } |
100 | return 0; | |
101 | } | |
b174baf4 | 102 | |
14555b14 | 103 | static int iio_store_to_kfifo(struct iio_buffer *r, |
5d65d920 | 104 | const void *data) |
b174baf4 JC |
105 | { |
106 | int ret; | |
107 | struct iio_kfifo *kf = iio_to_kfifo(r); | |
c559afbf JC |
108 | ret = kfifo_in(&kf->kf, data, 1); |
109 | if (ret != 1) | |
b174baf4 | 110 | return -EBUSY; |
7c388ec1 | 111 | r->stufftoread = true; |
623c334c | 112 | wake_up_interruptible_poll(&r->pollq, POLLIN | POLLRDNORM); |
c559afbf | 113 | |
b174baf4 JC |
114 | return 0; |
115 | } | |
b174baf4 | 116 | |
14555b14 | 117 | static int iio_read_first_n_kfifo(struct iio_buffer *r, |
b26a2188 | 118 | size_t n, char __user *buf) |
b174baf4 JC |
119 | { |
120 | int ret, copied; | |
121 | struct iio_kfifo *kf = iio_to_kfifo(r); | |
122 | ||
0894d80d LPC |
123 | if (mutex_lock_interruptible(&kf->user_lock)) |
124 | return -ERESTARTSYS; | |
8fe64955 | 125 | |
0894d80d LPC |
126 | if (!kfifo_initialized(&kf->kf) || n < kfifo_esize(&kf->kf)) |
127 | ret = -EINVAL; | |
128 | else | |
129 | ret = kfifo_to_user(&kf->kf, buf, n, &copied); | |
b174baf4 | 130 | |
7c388ec1 JC |
131 | if (kfifo_is_empty(&kf->kf)) |
132 | r->stufftoread = false; | |
133 | /* verify it is still empty to avoid race */ | |
134 | if (!kfifo_is_empty(&kf->kf)) | |
135 | r->stufftoread = true; | |
136 | ||
0894d80d LPC |
137 | mutex_unlock(&kf->user_lock); |
138 | if (ret < 0) | |
139 | return ret; | |
140 | ||
b174baf4 JC |
141 | return copied; |
142 | } | |
5565a450 | 143 | |
9e69c935 LPC |
144 | static void iio_kfifo_buffer_release(struct iio_buffer *buffer) |
145 | { | |
f6c23f48 LPC |
146 | struct iio_kfifo *kf = iio_to_kfifo(buffer); |
147 | ||
0894d80d | 148 | mutex_destroy(&kf->user_lock); |
f6c23f48 LPC |
149 | kfifo_free(&kf->kf); |
150 | kfree(kf); | |
9e69c935 LPC |
151 | } |
152 | ||
7e632344 | 153 | static const struct iio_buffer_access_funcs kfifo_access_funcs = { |
5565a450 JC |
154 | .store_to = &iio_store_to_kfifo, |
155 | .read_first_n = &iio_read_first_n_kfifo, | |
5565a450 JC |
156 | .request_update = &iio_request_update_kfifo, |
157 | .get_bytes_per_datum = &iio_get_bytes_per_datum_kfifo, | |
158 | .set_bytes_per_datum = &iio_set_bytes_per_datum_kfifo, | |
159 | .get_length = &iio_get_length_kfifo, | |
160 | .set_length = &iio_set_length_kfifo, | |
9e69c935 | 161 | .release = &iio_kfifo_buffer_release, |
5565a450 | 162 | }; |
7e632344 LPC |
163 | |
164 | struct iio_buffer *iio_kfifo_allocate(struct iio_dev *indio_dev) | |
165 | { | |
166 | struct iio_kfifo *kf; | |
167 | ||
168 | kf = kzalloc(sizeof *kf, GFP_KERNEL); | |
169 | if (!kf) | |
170 | return NULL; | |
171 | kf->update_needed = true; | |
172 | iio_buffer_init(&kf->buffer); | |
173 | kf->buffer.attrs = &iio_kfifo_attribute_group; | |
174 | kf->buffer.access = &kfifo_access_funcs; | |
7c388ec1 | 175 | kf->buffer.length = 2; |
0894d80d | 176 | mutex_init(&kf->user_lock); |
7e632344 LPC |
177 | return &kf->buffer; |
178 | } | |
179 | EXPORT_SYMBOL(iio_kfifo_allocate); | |
180 | ||
181 | void iio_kfifo_free(struct iio_buffer *r) | |
182 | { | |
9e69c935 | 183 | iio_buffer_put(r); |
7e632344 LPC |
184 | } |
185 | EXPORT_SYMBOL(iio_kfifo_free); | |
5565a450 | 186 | |
b174baf4 | 187 | MODULE_LICENSE("GPL"); |