2 * A generic kernel FIFO implementation
4 * Copyright (C) 2009/2010 Stefani Seibold <stefani@seibold.net>
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation; either version 2 of the License, or
9 * (at your option) any later version.
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
16 * You should have received a copy of the GNU General Public License
17 * along with this program; if not, write to the Free Software
18 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
22 #include <linux/kernel.h>
23 #include <linux/module.h>
24 #include <linux/slab.h>
25 #include <linux/err.h>
26 #include <linux/log2.h>
27 #include <linux/uaccess.h>
28 #include <linux/kfifo.h>
31 * internal helper to calculate the unused elements in a fifo
33 static inline unsigned int kfifo_unused(struct __kfifo
*fifo
)
35 return (fifo
->mask
+ 1) - (fifo
->in
- fifo
->out
);
38 int __kfifo_alloc(struct __kfifo
*fifo
, unsigned int size
,
39 size_t esize
, gfp_t gfp_mask
)
42 * round down to the next power of 2, since our 'let the indices
43 * wrap' technique works only in this case.
45 if (!is_power_of_2(size
))
46 size
= rounddown_pow_of_two(size
);
58 fifo
->data
= kmalloc(size
* esize
, gfp_mask
);
64 fifo
->mask
= size
- 1;
68 EXPORT_SYMBOL(__kfifo_alloc
);
70 void __kfifo_free(struct __kfifo
*fifo
)
79 EXPORT_SYMBOL(__kfifo_free
);
81 int __kfifo_init(struct __kfifo
*fifo
, void *buffer
,
82 unsigned int size
, size_t esize
)
86 if (!is_power_of_2(size
))
87 size
= rounddown_pow_of_two(size
);
98 fifo
->mask
= size
- 1;
102 EXPORT_SYMBOL(__kfifo_init
);
104 static void kfifo_copy_in(struct __kfifo
*fifo
, const void *src
,
105 unsigned int len
, unsigned int off
)
107 unsigned int size
= fifo
->mask
+ 1;
108 unsigned int esize
= fifo
->esize
;
117 l
= min(len
, size
- off
);
119 memcpy(fifo
->data
+ off
, src
, l
);
120 memcpy(fifo
->data
, src
+ l
, len
- l
);
122 * make sure that the data in the fifo is up to date before
123 * incrementing the fifo->in index counter
128 unsigned int __kfifo_in(struct __kfifo
*fifo
,
129 const void *buf
, unsigned int len
)
133 l
= kfifo_unused(fifo
);
137 kfifo_copy_in(fifo
, buf
, len
, fifo
->in
);
141 EXPORT_SYMBOL(__kfifo_in
);
143 static void kfifo_copy_out(struct __kfifo
*fifo
, void *dst
,
144 unsigned int len
, unsigned int off
)
146 unsigned int size
= fifo
->mask
+ 1;
147 unsigned int esize
= fifo
->esize
;
156 l
= min(len
, size
- off
);
158 memcpy(dst
, fifo
->data
+ off
, l
);
159 memcpy(dst
+ l
, fifo
->data
, len
- l
);
161 * make sure that the data is copied before
162 * incrementing the fifo->out index counter
167 unsigned int __kfifo_out_peek(struct __kfifo
*fifo
,
168 void *buf
, unsigned int len
)
172 l
= fifo
->in
- fifo
->out
;
176 kfifo_copy_out(fifo
, buf
, len
, fifo
->out
);
179 EXPORT_SYMBOL(__kfifo_out_peek
);
181 unsigned int __kfifo_out(struct __kfifo
*fifo
,
182 void *buf
, unsigned int len
)
184 len
= __kfifo_out_peek(fifo
, buf
, len
);
188 EXPORT_SYMBOL(__kfifo_out
);
190 static unsigned long kfifo_copy_from_user(struct __kfifo
*fifo
,
191 const void __user
*from
, unsigned int len
, unsigned int off
,
192 unsigned int *copied
)
194 unsigned int size
= fifo
->mask
+ 1;
195 unsigned int esize
= fifo
->esize
;
205 l
= min(len
, size
- off
);
207 ret
= copy_from_user(fifo
->data
+ off
, from
, l
);
209 ret
= DIV_ROUND_UP(ret
+ len
- l
, esize
);
211 ret
= copy_from_user(fifo
->data
, from
+ l
, len
- l
);
213 ret
= DIV_ROUND_UP(ret
, esize
);
216 * make sure that the data in the fifo is up to date before
217 * incrementing the fifo->in index counter
221 /* return the number of elements which are not copied */
225 int __kfifo_from_user(struct __kfifo
*fifo
, const void __user
*from
,
226 unsigned long len
, unsigned int *copied
)
230 unsigned int esize
= fifo
->esize
;
236 l
= kfifo_unused(fifo
);
240 ret
= kfifo_copy_from_user(fifo
, from
, len
, fifo
->in
, copied
);
249 EXPORT_SYMBOL(__kfifo_from_user
);
251 static unsigned long kfifo_copy_to_user(struct __kfifo
*fifo
, void __user
*to
,
252 unsigned int len
, unsigned int off
, unsigned int *copied
)
256 unsigned int size
= fifo
->mask
+ 1;
257 unsigned int esize
= fifo
->esize
;
265 l
= min(len
, size
- off
);
267 ret
= copy_to_user(to
, fifo
->data
+ off
, l
);
269 ret
= DIV_ROUND_UP(ret
+ len
- l
, esize
);
271 ret
= copy_to_user(to
+ l
, fifo
->data
, len
- l
);
273 ret
= DIV_ROUND_UP(ret
, esize
);
276 * make sure that the data is copied before
277 * incrementing the fifo->out index counter
281 /* return the number of elements which are not copied */
285 int __kfifo_to_user(struct __kfifo
*fifo
, void __user
*to
,
286 unsigned long len
, unsigned int *copied
)
290 unsigned int esize
= fifo
->esize
;
296 l
= fifo
->in
- fifo
->out
;
299 ret
= kfifo_copy_to_user(fifo
, to
, len
, fifo
->out
, copied
);
308 EXPORT_SYMBOL(__kfifo_to_user
);
310 static int setup_sgl_buf(struct scatterlist
*sgl
, void *buf
,
311 int nents
, unsigned int len
)
325 page
= virt_to_page(buf
);
326 off
= offset_in_page(buf
);
329 while (len
>= l
+ PAGE_SIZE
- off
) {
334 npage
= virt_to_page(buf
);
335 if (page_to_phys(page
) != page_to_phys(npage
) - l
) {
336 sg_set_page(sgl
, page
, l
- off
, off
);
338 if (++n
== nents
|| sgl
== NULL
)
345 sg_set_page(sgl
, page
, len
, off
);
349 static unsigned int setup_sgl(struct __kfifo
*fifo
, struct scatterlist
*sgl
,
350 int nents
, unsigned int len
, unsigned int off
)
352 unsigned int size
= fifo
->mask
+ 1;
353 unsigned int esize
= fifo
->esize
;
363 l
= min(len
, size
- off
);
365 n
= setup_sgl_buf(sgl
, fifo
->data
+ off
, nents
, l
);
366 n
+= setup_sgl_buf(sgl
+ n
, fifo
->data
, nents
- n
, len
- l
);
371 unsigned int __kfifo_dma_in_prepare(struct __kfifo
*fifo
,
372 struct scatterlist
*sgl
, int nents
, unsigned int len
)
376 l
= kfifo_unused(fifo
);
380 return setup_sgl(fifo
, sgl
, nents
, len
, fifo
->in
);
382 EXPORT_SYMBOL(__kfifo_dma_in_prepare
);
384 unsigned int __kfifo_dma_out_prepare(struct __kfifo
*fifo
,
385 struct scatterlist
*sgl
, int nents
, unsigned int len
)
389 l
= fifo
->in
- fifo
->out
;
393 return setup_sgl(fifo
, sgl
, nents
, len
, fifo
->out
);
395 EXPORT_SYMBOL(__kfifo_dma_out_prepare
);
397 unsigned int __kfifo_max_r(unsigned int len
, size_t recsize
)
399 unsigned int max
= (1 << (recsize
<< 3)) - 1;
406 #define __KFIFO_PEEK(data, out, mask) \
407 ((data)[(out) & (mask)])
409 * __kfifo_peek_n internal helper function for determinate the length of
410 * the next record in the fifo
412 static unsigned int __kfifo_peek_n(struct __kfifo
*fifo
, size_t recsize
)
415 unsigned int mask
= fifo
->mask
;
416 unsigned char *data
= fifo
->data
;
418 l
= __KFIFO_PEEK(data
, fifo
->out
, mask
);
421 l
|= __KFIFO_PEEK(data
, fifo
->out
+ 1, mask
) << 8;
426 #define __KFIFO_POKE(data, in, mask, val) \
428 (data)[(in) & (mask)] = (unsigned char)(val) \
432 * __kfifo_poke_n internal helper function for storeing the length of
433 * the record into the fifo
435 static void __kfifo_poke_n(struct __kfifo
*fifo
, unsigned int n
, size_t recsize
)
437 unsigned int mask
= fifo
->mask
;
438 unsigned char *data
= fifo
->data
;
440 __KFIFO_POKE(data
, fifo
->in
, mask
, n
);
443 __KFIFO_POKE(data
, fifo
->in
+ 1, mask
, n
>> 8);
446 unsigned int __kfifo_len_r(struct __kfifo
*fifo
, size_t recsize
)
448 return __kfifo_peek_n(fifo
, recsize
);
450 EXPORT_SYMBOL(__kfifo_len_r
);
452 unsigned int __kfifo_in_r(struct __kfifo
*fifo
, const void *buf
,
453 unsigned int len
, size_t recsize
)
455 if (len
+ recsize
> kfifo_unused(fifo
))
458 __kfifo_poke_n(fifo
, len
, recsize
);
460 kfifo_copy_in(fifo
, buf
, len
, fifo
->in
+ recsize
);
461 fifo
->in
+= len
+ recsize
;
464 EXPORT_SYMBOL(__kfifo_in_r
);
466 static unsigned int kfifo_out_copy_r(struct __kfifo
*fifo
,
467 void *buf
, unsigned int len
, size_t recsize
, unsigned int *n
)
469 *n
= __kfifo_peek_n(fifo
, recsize
);
474 kfifo_copy_out(fifo
, buf
, len
, fifo
->out
+ recsize
);
478 unsigned int __kfifo_out_peek_r(struct __kfifo
*fifo
, void *buf
,
479 unsigned int len
, size_t recsize
)
483 if (fifo
->in
== fifo
->out
)
486 return kfifo_out_copy_r(fifo
, buf
, len
, recsize
, &n
);
488 EXPORT_SYMBOL(__kfifo_out_peek_r
);
490 unsigned int __kfifo_out_r(struct __kfifo
*fifo
, void *buf
,
491 unsigned int len
, size_t recsize
)
495 if (fifo
->in
== fifo
->out
)
498 len
= kfifo_out_copy_r(fifo
, buf
, len
, recsize
, &n
);
499 fifo
->out
+= n
+ recsize
;
502 EXPORT_SYMBOL(__kfifo_out_r
);
504 void __kfifo_skip_r(struct __kfifo
*fifo
, size_t recsize
)
508 n
= __kfifo_peek_n(fifo
, recsize
);
509 fifo
->out
+= n
+ recsize
;
511 EXPORT_SYMBOL(__kfifo_skip_r
);
513 int __kfifo_from_user_r(struct __kfifo
*fifo
, const void __user
*from
,
514 unsigned long len
, unsigned int *copied
, size_t recsize
)
518 len
= __kfifo_max_r(len
, recsize
);
520 if (len
+ recsize
> kfifo_unused(fifo
)) {
525 __kfifo_poke_n(fifo
, len
, recsize
);
527 ret
= kfifo_copy_from_user(fifo
, from
, len
, fifo
->in
+ recsize
, copied
);
532 fifo
->in
+= len
+ recsize
;
535 EXPORT_SYMBOL(__kfifo_from_user_r
);
537 int __kfifo_to_user_r(struct __kfifo
*fifo
, void __user
*to
,
538 unsigned long len
, unsigned int *copied
, size_t recsize
)
543 if (fifo
->in
== fifo
->out
) {
548 n
= __kfifo_peek_n(fifo
, recsize
);
552 ret
= kfifo_copy_to_user(fifo
, to
, len
, fifo
->out
+ recsize
, copied
);
557 fifo
->out
+= n
+ recsize
;
560 EXPORT_SYMBOL(__kfifo_to_user_r
);
562 unsigned int __kfifo_dma_in_prepare_r(struct __kfifo
*fifo
,
563 struct scatterlist
*sgl
, int nents
, unsigned int len
, size_t recsize
)
568 len
= __kfifo_max_r(len
, recsize
);
570 if (len
+ recsize
> kfifo_unused(fifo
))
573 return setup_sgl(fifo
, sgl
, nents
, len
, fifo
->in
+ recsize
);
575 EXPORT_SYMBOL(__kfifo_dma_in_prepare_r
);
577 void __kfifo_dma_in_finish_r(struct __kfifo
*fifo
,
578 unsigned int len
, size_t recsize
)
580 len
= __kfifo_max_r(len
, recsize
);
581 __kfifo_poke_n(fifo
, len
, recsize
);
582 fifo
->in
+= len
+ recsize
;
584 EXPORT_SYMBOL(__kfifo_dma_in_finish_r
);
586 unsigned int __kfifo_dma_out_prepare_r(struct __kfifo
*fifo
,
587 struct scatterlist
*sgl
, int nents
, unsigned int len
, size_t recsize
)
592 len
= __kfifo_max_r(len
, recsize
);
594 if (len
+ recsize
> fifo
->in
- fifo
->out
)
597 return setup_sgl(fifo
, sgl
, nents
, len
, fifo
->out
+ recsize
);
599 EXPORT_SYMBOL(__kfifo_dma_out_prepare_r
);
601 void __kfifo_dma_out_finish_r(struct __kfifo
*fifo
, size_t recsize
)
605 len
= __kfifo_peek_n(fifo
, recsize
);
606 fifo
->out
+= len
+ recsize
;
608 EXPORT_SYMBOL(__kfifo_dma_out_finish_r
);