2  * A generic kernel FIFO implementation
31  * internal helper to calculate the unused elements in a fifo
33 static inline unsigned int kfifo_unused(struct __kfifo *fifo)  in kfifo_unused()  argument
35 	return (fifo->mask + 1) - (fifo->in - fifo->out);  in kfifo_unused()
38 int __kfifo_alloc(struct __kfifo *fifo, unsigned int size,  in __kfifo_alloc()  argument
48 	fifo->in = 0;  in __kfifo_alloc()
49 	fifo->out = 0;  in __kfifo_alloc()
50 	fifo->esize = esize;  in __kfifo_alloc()
53 		fifo->data = NULL;  in __kfifo_alloc()
54 		fifo->mask = 0;  in __kfifo_alloc()
58 	fifo->data = kmalloc(size * esize, gfp_mask);  in __kfifo_alloc()
60 	if (!fifo->data) {  in __kfifo_alloc()
61 		fifo->mask = 0;  in __kfifo_alloc()
64 	fifo->mask = size - 1;  in __kfifo_alloc()
70 void __kfifo_free(struct __kfifo *fifo)  in __kfifo_free()  argument
72 	kfree(fifo->data);  in __kfifo_free()
73 	fifo->in = 0;  in __kfifo_free()
74 	fifo->out = 0;  in __kfifo_free()
75 	fifo->esize = 0;  in __kfifo_free()
76 	fifo->data = NULL;  in __kfifo_free()
77 	fifo->mask = 0;  in __kfifo_free()
81 int __kfifo_init(struct __kfifo *fifo, void *buffer,  in __kfifo_init()  argument
89 	fifo->in = 0;  in __kfifo_init()
90 	fifo->out = 0;  in __kfifo_init()
91 	fifo->esize = esize;  in __kfifo_init()
92 	fifo->data = buffer;  in __kfifo_init()
95 		fifo->mask = 0;  in __kfifo_init()
98 	fifo->mask = size - 1;  in __kfifo_init()
104 static void kfifo_copy_in(struct __kfifo *fifo, const void *src,  in kfifo_copy_in()  argument
107 	unsigned int size = fifo->mask + 1;  in kfifo_copy_in()
108 	unsigned int esize = fifo->esize;  in kfifo_copy_in()
111 	off &= fifo->mask;  in kfifo_copy_in()
119 	memcpy(fifo->data + off, src, l);  in kfifo_copy_in()
120 	memcpy(fifo->data, src + l, len - l);  in kfifo_copy_in()
122 	 * make sure that the data in the fifo is up to date before  in kfifo_copy_in()
123 	 * incrementing the fifo->in index counter  in kfifo_copy_in()
128 unsigned int __kfifo_in(struct __kfifo *fifo,  in __kfifo_in()  argument
133 	l = kfifo_unused(fifo);  in __kfifo_in()
137 	kfifo_copy_in(fifo, buf, len, fifo->in);  in __kfifo_in()
138 	fifo->in += len;  in __kfifo_in()
143 static void kfifo_copy_out(struct __kfifo *fifo, void *dst,  in kfifo_copy_out()  argument
146 	unsigned int size = fifo->mask + 1;  in kfifo_copy_out()
147 	unsigned int esize = fifo->esize;  in kfifo_copy_out()
150 	off &= fifo->mask;  in kfifo_copy_out()
158 	memcpy(dst, fifo->data + off, l);  in kfifo_copy_out()
159 	memcpy(dst + l, fifo->data, len - l);  in kfifo_copy_out()
162 	 * incrementing the fifo->out index counter  in kfifo_copy_out()
167 unsigned int __kfifo_out_peek(struct __kfifo *fifo,  in __kfifo_out_peek()  argument
172 	l = fifo->in - fifo->out;  in __kfifo_out_peek()
176 	kfifo_copy_out(fifo, buf, len, fifo->out);  in __kfifo_out_peek()
181 unsigned int __kfifo_out(struct __kfifo *fifo,  in __kfifo_out()  argument
184 	len = __kfifo_out_peek(fifo, buf, len);  in __kfifo_out()
185 	fifo->out += len;  in __kfifo_out()
190 static unsigned long kfifo_copy_from_user(struct __kfifo *fifo,  in kfifo_copy_from_user()  argument
194 	unsigned int size = fifo->mask + 1;  in kfifo_copy_from_user()
195 	unsigned int esize = fifo->esize;  in kfifo_copy_from_user()
199 	off &= fifo->mask;  in kfifo_copy_from_user()
207 	ret = copy_from_user(fifo->data + off, from, l);  in kfifo_copy_from_user()
211 		ret = copy_from_user(fifo->data, from + l, len - l);  in kfifo_copy_from_user()
216 	 * make sure that the data in the fifo is up to date before  in kfifo_copy_from_user()
217 	 * incrementing the fifo->in index counter  in kfifo_copy_from_user()
225 int __kfifo_from_user(struct __kfifo *fifo, const void __user *from,  in __kfifo_from_user()  argument
230 	unsigned int esize = fifo->esize;  in __kfifo_from_user()
236 	l = kfifo_unused(fifo);  in __kfifo_from_user()
240 	ret = kfifo_copy_from_user(fifo, from, len, fifo->in, copied);  in __kfifo_from_user()
246 	fifo->in += len;  in __kfifo_from_user()
251 static unsigned long kfifo_copy_to_user(struct __kfifo *fifo, void __user *to,  in kfifo_copy_to_user()  argument
256 	unsigned int size = fifo->mask + 1;  in kfifo_copy_to_user()
257 	unsigned int esize = fifo->esize;  in kfifo_copy_to_user()
259 	off &= fifo->mask;  in kfifo_copy_to_user()
267 	ret = copy_to_user(to, fifo->data + off, l);  in kfifo_copy_to_user()
271 		ret = copy_to_user(to + l, fifo->data, len - l);  in kfifo_copy_to_user()
277 	 * incrementing the fifo->out index counter  in kfifo_copy_to_user()
285 int __kfifo_to_user(struct __kfifo *fifo, void __user *to,  in __kfifo_to_user()  argument
290 	unsigned int esize = fifo->esize;  in __kfifo_to_user()
296 	l = fifo->in - fifo->out;  in __kfifo_to_user()
299 	ret = kfifo_copy_to_user(fifo, to, len, fifo->out, copied);  in __kfifo_to_user()
305 	fifo->out += len;  in __kfifo_to_user()
349 static unsigned int setup_sgl(struct __kfifo *fifo, struct scatterlist *sgl,  in setup_sgl()  argument
352 	unsigned int size = fifo->mask + 1;  in setup_sgl()
353 	unsigned int esize = fifo->esize;  in setup_sgl()
357 	off &= fifo->mask;  in setup_sgl()
365 	n = setup_sgl_buf(sgl, fifo->data + off, nents, l);  in setup_sgl()
366 	n += setup_sgl_buf(sgl + n, fifo->data, nents - n, len - l);  in setup_sgl()
371 unsigned int __kfifo_dma_in_prepare(struct __kfifo *fifo,  in __kfifo_dma_in_prepare()  argument
376 	l = kfifo_unused(fifo);  in __kfifo_dma_in_prepare()
380 	return setup_sgl(fifo, sgl, nents, len, fifo->in);  in __kfifo_dma_in_prepare()
384 unsigned int __kfifo_dma_out_prepare(struct __kfifo *fifo,  in __kfifo_dma_out_prepare()  argument
389 	l = fifo->in - fifo->out;  in __kfifo_dma_out_prepare()
393 	return setup_sgl(fifo, sgl, nents, len, fifo->out);  in __kfifo_dma_out_prepare()
410  * the next record in the fifo
412 static unsigned int __kfifo_peek_n(struct __kfifo *fifo, size_t recsize)  in __kfifo_peek_n()  argument
415 	unsigned int mask = fifo->mask;  in __kfifo_peek_n()
416 	unsigned char *data = fifo->data;  in __kfifo_peek_n()
418 	l = __KFIFO_PEEK(data, fifo->out, mask);  in __kfifo_peek_n()
421 		l |= __KFIFO_PEEK(data, fifo->out + 1, mask) << 8;  in __kfifo_peek_n()
433  * the record into the fifo
435 static void __kfifo_poke_n(struct __kfifo *fifo, unsigned int n, size_t recsize)  in __kfifo_poke_n()  argument
437 	unsigned int mask = fifo->mask;  in __kfifo_poke_n()
438 	unsigned char *data = fifo->data;  in __kfifo_poke_n()
440 	__KFIFO_POKE(data, fifo->in, mask, n);  in __kfifo_poke_n()
443 		__KFIFO_POKE(data, fifo->in + 1, mask, n >> 8);  in __kfifo_poke_n()
446 unsigned int __kfifo_len_r(struct __kfifo *fifo, size_t recsize)  in __kfifo_len_r()  argument
448 	return __kfifo_peek_n(fifo, recsize);  in __kfifo_len_r()
452 unsigned int __kfifo_in_r(struct __kfifo *fifo, const void *buf,  in __kfifo_in_r()  argument
455 	if (len + recsize > kfifo_unused(fifo))  in __kfifo_in_r()
458 	__kfifo_poke_n(fifo, len, recsize);  in __kfifo_in_r()
460 	kfifo_copy_in(fifo, buf, len, fifo->in + recsize);  in __kfifo_in_r()
461 	fifo->in += len + recsize;  in __kfifo_in_r()
466 static unsigned int kfifo_out_copy_r(struct __kfifo *fifo,  in kfifo_out_copy_r()  argument
469 	*n = __kfifo_peek_n(fifo, recsize);  in kfifo_out_copy_r()
474 	kfifo_copy_out(fifo, buf, len, fifo->out + recsize);  in kfifo_out_copy_r()
478 unsigned int __kfifo_out_peek_r(struct __kfifo *fifo, void *buf,  in __kfifo_out_peek_r()  argument
483 	if (fifo->in == fifo->out)  in __kfifo_out_peek_r()
486 	return kfifo_out_copy_r(fifo, buf, len, recsize, &n);  in __kfifo_out_peek_r()
490 unsigned int __kfifo_out_r(struct __kfifo *fifo, void *buf,  in __kfifo_out_r()  argument
495 	if (fifo->in == fifo->out)  in __kfifo_out_r()
498 	len = kfifo_out_copy_r(fifo, buf, len, recsize, &n);  in __kfifo_out_r()
499 	fifo->out += n + recsize;  in __kfifo_out_r()
504 void __kfifo_skip_r(struct __kfifo *fifo, size_t recsize)  in __kfifo_skip_r()  argument
508 	n = __kfifo_peek_n(fifo, recsize);  in __kfifo_skip_r()
509 	fifo->out += n + recsize;  in __kfifo_skip_r()
513 int __kfifo_from_user_r(struct __kfifo *fifo, const void __user *from,  in __kfifo_from_user_r()  argument
520 	if (len + recsize > kfifo_unused(fifo)) {  in __kfifo_from_user_r()
525 	__kfifo_poke_n(fifo, len, recsize);  in __kfifo_from_user_r()
527 	ret = kfifo_copy_from_user(fifo, from, len, fifo->in + recsize, copied);  in __kfifo_from_user_r()
532 	fifo->in += len + recsize;  in __kfifo_from_user_r()
537 int __kfifo_to_user_r(struct __kfifo *fifo, void __user *to,  in __kfifo_to_user_r()  argument
543 	if (fifo->in == fifo->out) {  in __kfifo_to_user_r()
548 	n = __kfifo_peek_n(fifo, recsize);  in __kfifo_to_user_r()
552 	ret = kfifo_copy_to_user(fifo, to, len, fifo->out + recsize, copied);  in __kfifo_to_user_r()
557 	fifo->out += n + recsize;  in __kfifo_to_user_r()
562 unsigned int __kfifo_dma_in_prepare_r(struct __kfifo *fifo,  in __kfifo_dma_in_prepare_r()  argument
570 	if (len + recsize > kfifo_unused(fifo))  in __kfifo_dma_in_prepare_r()
573 	return setup_sgl(fifo, sgl, nents, len, fifo->in + recsize);  in __kfifo_dma_in_prepare_r()
577 void __kfifo_dma_in_finish_r(struct __kfifo *fifo,  in __kfifo_dma_in_finish_r()  argument
581 	__kfifo_poke_n(fifo, len, recsize);  in __kfifo_dma_in_finish_r()
582 	fifo->in += len + recsize;  in __kfifo_dma_in_finish_r()
586 unsigned int __kfifo_dma_out_prepare_r(struct __kfifo *fifo,  in __kfifo_dma_out_prepare_r()  argument
594 	if (len + recsize > fifo->in - fifo->out)  in __kfifo_dma_out_prepare_r()
597 	return setup_sgl(fifo, sgl, nents, len, fifo->out + recsize);  in __kfifo_dma_out_prepare_r()
601 void __kfifo_dma_out_finish_r(struct __kfifo *fifo, size_t recsize)  in __kfifo_dma_out_finish_r()  argument
605 	len = __kfifo_peek_n(fifo, recsize);  in __kfifo_dma_out_finish_r()
606 	fifo->out += len + recsize;  in __kfifo_dma_out_finish_r()