[GitHub/mt8127/android_kernel_alcatel_ttab.git] / drivers / staging / comedi / comedi_buf.c

/*
 * comedi_buf.c
 *
 * COMEDI - Linux Control and Measurement Device Interface
 * Copyright (C) 1997-2000 David A. Schleef <ds@schleef.org>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

#include "comedidev.h"
#include "comedi_internal.h"

#ifdef PAGE_KERNEL_NOCACHE
#define COMEDI_PAGE_PROTECTION		PAGE_KERNEL_NOCACHE
#else
#define COMEDI_PAGE_PROTECTION		PAGE_KERNEL
#endif

static void __comedi_buf_free(struct comedi_device *dev,
			      struct comedi_subdevice *s,
			      unsigned n_pages)
{
	struct comedi_async *async = s->async;
	struct comedi_buf_page *buf;
	unsigned i;

	if (async->prealloc_buf) {
		vunmap(async->prealloc_buf);
		async->prealloc_buf = NULL;
		async->prealloc_bufsz = 0;
	}

	if (!async->buf_page_list)
		return;

	for (i = 0; i < n_pages; ++i) {
		buf = &async->buf_page_list[i];
		if (buf->virt_addr) {
			clear_bit(PG_reserved,
				  &(virt_to_page(buf->virt_addr)->flags));
			if (s->async_dma_dir != DMA_NONE) {
#ifdef CONFIG_HAS_DMA
				dma_free_coherent(dev->hw_dev,
						  PAGE_SIZE,
						  buf->virt_addr,
						  buf->dma_addr);
#endif
			} else {
				free_page((unsigned long)buf->virt_addr);
			}
		}
	}
	vfree(async->buf_page_list);
	async->buf_page_list = NULL;
	async->n_buf_pages = 0;
}

static void __comedi_buf_alloc(struct comedi_device *dev,
			       struct comedi_subdevice *s,
			       unsigned n_pages)
{
	struct comedi_async *async = s->async;
	struct page **pages = NULL;
	struct comedi_buf_page *buf;
	unsigned i;

	if (!IS_ENABLED(CONFIG_HAS_DMA) && s->async_dma_dir != DMA_NONE) {
		dev_err(dev->class_dev,
			"dma buffer allocation not supported\n");
		return;
	}

	async->buf_page_list = vzalloc(sizeof(*buf) * n_pages);
	if (async->buf_page_list)
		pages = vmalloc(sizeof(struct page *) * n_pages);

	if (!pages)
		return;

	for (i = 0; i < n_pages; i++) {
		buf = &async->buf_page_list[i];
		if (s->async_dma_dir != DMA_NONE)
#ifdef CONFIG_HAS_DMA
			buf->virt_addr = dma_alloc_coherent(dev->hw_dev,
							    PAGE_SIZE,
							    &buf->dma_addr,
							    GFP_KERNEL |
							    __GFP_COMP);
#else
			break;
#endif
		else
			buf->virt_addr = (void *)get_zeroed_page(GFP_KERNEL);
		if (!buf->virt_addr)
			break;

		set_bit(PG_reserved, &(virt_to_page(buf->virt_addr)->flags));

		pages[i] = virt_to_page(buf->virt_addr);
	}

	/* vmap the prealloc_buf if all the pages were allocated */
	if (i == n_pages)
		async->prealloc_buf = vmap(pages, n_pages, VM_MAP,
					   COMEDI_PAGE_PROTECTION);

	vfree(pages);
}

int comedi_buf_alloc(struct comedi_device *dev, struct comedi_subdevice *s,
		     unsigned long new_size)
{
	struct comedi_async *async = s->async;

	/* Round up new_size to multiple of PAGE_SIZE */
	new_size = (new_size + PAGE_SIZE - 1) & PAGE_MASK;

	/* if no change is required, do nothing */
	if (async->prealloc_buf && async->prealloc_bufsz == new_size)
		return 0;

	/* deallocate old buffer */
	__comedi_buf_free(dev, s, async->n_buf_pages);

	/* allocate new buffer */
	if (new_size) {
		unsigned n_pages = new_size >> PAGE_SHIFT;

		__comedi_buf_alloc(dev, s, n_pages);

		if (!async->prealloc_buf) {
			/* allocation failed */
			__comedi_buf_free(dev, s, n_pages);
			return -ENOMEM;
		}
		async->n_buf_pages = n_pages;
	}
	async->prealloc_bufsz = new_size;

	return 0;
}

void comedi_buf_reset(struct comedi_async *async)
{
	async->buf_write_alloc_count = 0;
	async->buf_write_count = 0;
	async->buf_read_alloc_count = 0;
	async->buf_read_count = 0;

	async->buf_write_ptr = 0;
	async->buf_read_ptr = 0;

	async->cur_chan = 0;
	async->scan_progress = 0;
	async->munge_chan = 0;
	async->munge_count = 0;
	async->munge_ptr = 0;

	async->events = 0;
}

static unsigned int comedi_buf_write_n_available(struct comedi_async *async)
{
	unsigned int free_end = async->buf_read_count + async->prealloc_bufsz;

	return free_end - async->buf_write_alloc_count;
}

static unsigned int __comedi_buf_write_alloc(struct comedi_async *async,
					     unsigned int nbytes,
					     int strict)
{
	unsigned int available = comedi_buf_write_n_available(async);

	if (nbytes > available)
		nbytes = strict ? 0 : available;

	async->buf_write_alloc_count += nbytes;

	/*
	 * ensure the async buffer 'counts' are read and updated
	 * before we write data to the write-alloc'ed buffer space
	 */
	smp_mb();

	return nbytes;
}

/* allocates chunk for the writer from free buffer space */
unsigned int comedi_buf_write_alloc(struct comedi_async *async,
				    unsigned int nbytes)
{
	return __comedi_buf_write_alloc(async, nbytes, 0);
}
EXPORT_SYMBOL_GPL(comedi_buf_write_alloc);

/*
 * munging is applied to data by core as it passes between user
 * and kernel space
 */
static unsigned int comedi_buf_munge(struct comedi_async *async,
				     unsigned int num_bytes)
{
	struct comedi_subdevice *s = async->subdevice;
	unsigned int count = 0;
	const unsigned num_sample_bytes = bytes_per_sample(s);

	if (!s->munge || (async->cmd.flags & CMDF_RAWDATA)) {
		async->munge_count += num_bytes;
		count = num_bytes;
	} else {
		/* don't munge partial samples */
		num_bytes -= num_bytes % num_sample_bytes;
		while (count < num_bytes) {
			int block_size = num_bytes - count;
			unsigned int buf_end;

			buf_end = async->prealloc_bufsz - async->munge_ptr;
			if (block_size > buf_end)
				block_size = buf_end;

			s->munge(s->device, s,
				 async->prealloc_buf + async->munge_ptr,
				 block_size, async->munge_chan);

			/*
			 * ensure data is munged in buffer before the
			 * async buffer munge_count is incremented
			 */
			smp_wmb();

			async->munge_chan += block_size / num_sample_bytes;
			async->munge_chan %= async->cmd.chanlist_len;
			async->munge_count += block_size;
			async->munge_ptr += block_size;
			async->munge_ptr %= async->prealloc_bufsz;
			count += block_size;
		}
	}

	return count;
}

unsigned int comedi_buf_write_n_allocated(struct comedi_async *async)
{
	return async->buf_write_alloc_count - async->buf_write_count;
}

/* transfers a chunk from writer to filled buffer space */
unsigned int comedi_buf_write_free(struct comedi_async *async,
				   unsigned int nbytes)
{
	unsigned int allocated = comedi_buf_write_n_allocated(async);

	if (nbytes > allocated)
		nbytes = allocated;

	async->buf_write_count += nbytes;
	async->buf_write_ptr += nbytes;
	comedi_buf_munge(async, async->buf_write_count - async->munge_count);
	if (async->buf_write_ptr >= async->prealloc_bufsz)
		async->buf_write_ptr %= async->prealloc_bufsz;

	return nbytes;
}
EXPORT_SYMBOL_GPL(comedi_buf_write_free);

unsigned int comedi_buf_read_n_available(struct comedi_async *async)
{
	unsigned num_bytes;

	if (!async)
		return 0;

	num_bytes = async->munge_count - async->buf_read_count;

	/*
	 * ensure the async buffer 'counts' are read before we
	 * attempt to read data from the buffer
	 */
	smp_rmb();

	return num_bytes;
}
EXPORT_SYMBOL_GPL(comedi_buf_read_n_available);

/* allocates a chunk for the reader from filled (and munged) buffer space */
unsigned int comedi_buf_read_alloc(struct comedi_async *async,
				   unsigned int nbytes)
{
	unsigned int available;

	available = async->munge_count - async->buf_read_alloc_count;
	if (nbytes > available)
		nbytes = available;

	async->buf_read_alloc_count += nbytes;

	/*
	 * ensure the async buffer 'counts' are read before we
	 * attempt to read data from the read-alloc'ed buffer space
	 */
	smp_rmb();

	return nbytes;
}
EXPORT_SYMBOL_GPL(comedi_buf_read_alloc);

static unsigned int comedi_buf_read_n_allocated(struct comedi_async *async)
{
	return async->buf_read_alloc_count - async->buf_read_count;
}

/* transfers control of a chunk from reader to free buffer space */
unsigned int comedi_buf_read_free(struct comedi_async *async,
				  unsigned int nbytes)
{
	unsigned int allocated;

	/*
	 * ensure data has been read out of buffer before
	 * the async read count is incremented
	 */
	smp_mb();

	allocated = comedi_buf_read_n_allocated(async);
	if (nbytes > allocated)
		nbytes = allocated;

	async->buf_read_count += nbytes;
	async->buf_read_ptr += nbytes;
	async->buf_read_ptr %= async->prealloc_bufsz;
	return nbytes;
}
EXPORT_SYMBOL_GPL(comedi_buf_read_free);

int comedi_buf_put(struct comedi_async *async, short x)
{
	unsigned int n = __comedi_buf_write_alloc(async, sizeof(short), 1);

	if (n < sizeof(short)) {
		async->events |= COMEDI_CB_ERROR;
		return 0;
	}
	*(short *)(async->prealloc_buf + async->buf_write_ptr) = x;
	comedi_buf_write_free(async, sizeof(short));
	return 1;
}
EXPORT_SYMBOL_GPL(comedi_buf_put);

int comedi_buf_get(struct comedi_async *async, short *x)
{
	unsigned int n = comedi_buf_read_n_available(async);

	if (n < sizeof(short))
		return 0;
	comedi_buf_read_alloc(async, sizeof(short));
	*x = *(short *)(async->prealloc_buf + async->buf_read_ptr);
	comedi_buf_read_free(async, sizeof(short));
	return 1;
}
EXPORT_SYMBOL_GPL(comedi_buf_get);

void comedi_buf_memcpy_to(struct comedi_async *async, unsigned int offset,
			  const void *data, unsigned int num_bytes)
{
	unsigned int write_ptr = async->buf_write_ptr + offset;

	if (write_ptr >= async->prealloc_bufsz)
		write_ptr %= async->prealloc_bufsz;

	while (num_bytes) {
		unsigned int block_size;

		if (write_ptr + num_bytes > async->prealloc_bufsz)
			block_size = async->prealloc_bufsz - write_ptr;
		else
			block_size = num_bytes;

		memcpy(async->prealloc_buf + write_ptr, data, block_size);

		data += block_size;
		num_bytes -= block_size;

		write_ptr = 0;
	}
}
EXPORT_SYMBOL_GPL(comedi_buf_memcpy_to);

void comedi_buf_memcpy_from(struct comedi_async *async, unsigned int offset,
			    void *dest, unsigned int nbytes)
{
	void *src;
	unsigned int read_ptr = async->buf_read_ptr + offset;

	if (read_ptr >= async->prealloc_bufsz)
		read_ptr %= async->prealloc_bufsz;

	while (nbytes) {
		unsigned int block_size;

		src = async->prealloc_buf + read_ptr;

		if (nbytes >= async->prealloc_bufsz - read_ptr)
			block_size = async->prealloc_bufsz - read_ptr;
		else
			block_size = nbytes;

		memcpy(dest, src, block_size);
		nbytes -= block_size;
		dest += block_size;
		read_ptr = 0;
	}
}
EXPORT_SYMBOL_GPL(comedi_buf_memcpy_from);
Commit	Line	Data
ea082fb1 HS	1	/*
	2	* comedi_buf.c
	3	*
	4	* COMEDI - Linux Control and Measurement Device Interface
	5	* Copyright (C) 1997-2000 David A. Schleef <ds@schleef.org>
	6	*
	7	* This program is free software; you can redistribute it and/or modify
	8	* it under the terms of the GNU General Public License as published by
	9	* the Free Software Foundation; either version 2 of the License, or
	10	* (at your option) any later version.
	11	*
	12	* This program is distributed in the hope that it will be useful,
	13	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	14	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	15	* GNU General Public License for more details.
	16	*
	17	* You should have received a copy of the GNU General Public License
	18	* along with this program; if not, write to the Free Software
	19	* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
	20	*/
	21
	22	#include "comedidev.h"
	23	#include "comedi_internal.h"
	24
6bd76457 HS	25	#ifdef PAGE_KERNEL_NOCACHE
	26	#define COMEDI_PAGE_PROTECTION PAGE_KERNEL_NOCACHE
	27	#else
	28	#define COMEDI_PAGE_PROTECTION PAGE_KERNEL
	29	#endif
	30
718c4d68 HS	31	static void __comedi_buf_free(struct comedi_device *dev,
	32	struct comedi_subdevice *s,
	33	unsigned n_pages)
	34	{
	35	struct comedi_async *async = s->async;
	36	struct comedi_buf_page *buf;
	37	unsigned i;
	38
	39	if (async->prealloc_buf) {
	40	vunmap(async->prealloc_buf);
	41	async->prealloc_buf = NULL;
	42	async->prealloc_bufsz = 0;
	43	}
	44
	45	if (!async->buf_page_list)
	46	return;
	47
	48	for (i = 0; i < n_pages; ++i) {
	49	buf = &async->buf_page_list[i];
	50	if (buf->virt_addr) {
	51	clear_bit(PG_reserved,
	52	&(virt_to_page(buf->virt_addr)->flags));
	53	if (s->async_dma_dir != DMA_NONE) {
4efc4bbd	54	#ifdef CONFIG_HAS_DMA
718c4d68 HS	55	dma_free_coherent(dev->hw_dev,
	56	PAGE_SIZE,
	57	buf->virt_addr,
	58	buf->dma_addr);
4efc4bbd	59	#endif
718c4d68 HS	60	} else {
	61	free_page((unsigned long)buf->virt_addr);
	62	}
	63	}
	64	}
	65	vfree(async->buf_page_list);
	66	async->buf_page_list = NULL;
	67	async->n_buf_pages = 0;
	68	}
	69
6bd76457 HS	70	static void __comedi_buf_alloc(struct comedi_device *dev,
	71	struct comedi_subdevice *s,
	72	unsigned n_pages)
	73	{
	74	struct comedi_async *async = s->async;
	75	struct page **pages = NULL;
	76	struct comedi_buf_page *buf;
	77	unsigned i;
	78
e9166139 IA	79	if (!IS_ENABLED(CONFIG_HAS_DMA) && s->async_dma_dir != DMA_NONE) {
	80	dev_err(dev->class_dev,
	81	"dma buffer allocation not supported\n");
	82	return;
	83	}
	84
6bd76457 HS	85	async->buf_page_list = vzalloc(sizeof(buf) n_pages);
	86	if (async->buf_page_list)
	87	pages = vmalloc(sizeof(struct page ) n_pages);
	88
	89	if (!pages)
	90	return;
	91
	92	for (i = 0; i < n_pages; i++) {
	93	buf = &async->buf_page_list[i];
	94	if (s->async_dma_dir != DMA_NONE)
4efc4bbd	95	#ifdef CONFIG_HAS_DMA
6bd76457 HS	96	buf->virt_addr = dma_alloc_coherent(dev->hw_dev,
	97	PAGE_SIZE,
	98	&buf->dma_addr,
	99	GFP_KERNEL \|
	100	__GFP_COMP);
4efc4bbd IA	101	#else
	102	break;
	103	#endif
6bd76457 HS	104	else
	105	buf->virt_addr = (void *)get_zeroed_page(GFP_KERNEL);
	106	if (!buf->virt_addr)
	107	break;
	108
	109	set_bit(PG_reserved, &(virt_to_page(buf->virt_addr)->flags));
	110
	111	pages[i] = virt_to_page(buf->virt_addr);
	112	}
	113
	114	/* vmap the prealloc_buf if all the pages were allocated */
	115	if (i == n_pages)
	116	async->prealloc_buf = vmap(pages, n_pages, VM_MAP,
	117	COMEDI_PAGE_PROTECTION);
	118
	119	vfree(pages);
	120	}
	121
ea082fb1 HS	122	int comedi_buf_alloc(struct comedi_device dev, struct comedi_subdevice s,
	123	unsigned long new_size)
	124	{
	125	struct comedi_async *async = s->async;
	126
	127	/* Round up new_size to multiple of PAGE_SIZE */
	128	new_size = (new_size + PAGE_SIZE - 1) & PAGE_MASK;
	129
	130	/* if no change is required, do nothing */
	131	if (async->prealloc_buf && async->prealloc_bufsz == new_size)
	132	return 0;
	133
718c4d68 HS	134	/* deallocate old buffer */
	135	__comedi_buf_free(dev, s, async->n_buf_pages);
	136
6bd76457	137	/* allocate new buffer */
ea082fb1	138	if (new_size) {
ea082fb1	139	unsigned n_pages = new_size >> PAGE_SHIFT;
6bd76457 HS	140
6bd76457 HS	141	__comedi_buf_alloc(dev, s, n_pages);
ea082fb1	142
718c4d68	143	if (!async->prealloc_buf) {
6bd76457	144	/* allocation failed */
718c4d68	145	__comedi_buf_free(dev, s, n_pages);
ea082fb1 HS	146	return -ENOMEM;
	147	}
	148	async->n_buf_pages = n_pages;
	149	}
	150	async->prealloc_bufsz = new_size;
	151
	152	return 0;
	153	}
	154
61c9fb0e	155	void comedi_buf_reset(struct comedi_async *async)
ea082fb1 HS	156	{
	157	async->buf_write_alloc_count = 0;
	158	async->buf_write_count = 0;
	159	async->buf_read_alloc_count = 0;
	160	async->buf_read_count = 0;
	161
	162	async->buf_write_ptr = 0;
	163	async->buf_read_ptr = 0;
	164
	165	async->cur_chan = 0;
	166	async->scan_progress = 0;
	167	async->munge_chan = 0;
	168	async->munge_count = 0;
	169	async->munge_ptr = 0;
	170
	171	async->events = 0;
	172	}
	173
f8f76e90	174	static unsigned int comedi_buf_write_n_available(struct comedi_async *async)
ea082fb1	175	{
f8f76e90	176	unsigned int free_end = async->buf_read_count + async->prealloc_bufsz;
ea082fb1	177
f8f76e90 HS	178	return free_end - async->buf_write_alloc_count;
	179	}
	180
	181	static unsigned int __comedi_buf_write_alloc(struct comedi_async *async,
	182	unsigned int nbytes,
	183	int strict)
	184	{
	185	unsigned int available = comedi_buf_write_n_available(async);
	186
	187	if (nbytes > available)
	188	nbytes = strict ? 0 : available;
ea082fb1	189
f8f76e90 HS	190	async->buf_write_alloc_count += nbytes;
	191
	192	/*
	193	* ensure the async buffer 'counts' are read and updated
	194	* before we write data to the write-alloc'ed buffer space
ea082fb1 HS	195	*/
ea082fb1 HS	196	smp_mb();
f8f76e90	197
ea082fb1 HS	198	return nbytes;
	199	}
	200
	201	/* allocates chunk for the writer from free buffer space */
	202	unsigned int comedi_buf_write_alloc(struct comedi_async *async,
	203	unsigned int nbytes)
	204	{
f8f76e90	205	return __comedi_buf_write_alloc(async, nbytes, 0);
ea082fb1	206	}
5660e742	207	EXPORT_SYMBOL_GPL(comedi_buf_write_alloc);
ea082fb1	208
8d4be669 HS	209	/*
	210	* munging is applied to data by core as it passes between user
	211	* and kernel space
	212	*/
ea082fb1 HS	213	static unsigned int comedi_buf_munge(struct comedi_async *async,
	214	unsigned int num_bytes)
	215	{
	216	struct comedi_subdevice *s = async->subdevice;
	217	unsigned int count = 0;
	218	const unsigned num_sample_bytes = bytes_per_sample(s);
	219
8d4be669	220	if (!s->munge \|\| (async->cmd.flags & CMDF_RAWDATA)) {
ea082fb1	221	async->munge_count += num_bytes;
8d4be669 HS	222	count = num_bytes;
	223	} else {
	224	/* don't munge partial samples */
	225	num_bytes -= num_bytes % num_sample_bytes;
	226	while (count < num_bytes) {
	227	int block_size = num_bytes - count;
	228	unsigned int buf_end;
	229
8d4be669 HS	230	buf_end = async->prealloc_bufsz - async->munge_ptr;
	231	if (block_size > buf_end)
	232	block_size = buf_end;
	233
	234	s->munge(s->device, s,
	235	async->prealloc_buf + async->munge_ptr,
	236	block_size, async->munge_chan);
	237
	238	/*
	239	* ensure data is munged in buffer before the
	240	* async buffer munge_count is incremented
	241	*/
	242	smp_wmb();
	243
	244	async->munge_chan += block_size / num_sample_bytes;
	245	async->munge_chan %= async->cmd.chanlist_len;
	246	async->munge_count += block_size;
	247	async->munge_ptr += block_size;
	248	async->munge_ptr %= async->prealloc_bufsz;
	249	count += block_size;
ea082fb1	250	}
ea082fb1	251	}
8d4be669	252
ea082fb1 HS	253	return count;
	254	}
	255
8bd650f9 HS	256	unsigned int comedi_buf_write_n_allocated(struct comedi_async *async)
	257	{
	258	return async->buf_write_alloc_count - async->buf_write_count;
	259	}
	260
ea082fb1	261	/* transfers a chunk from writer to filled buffer space */
8ae560a1 HS	262	unsigned int comedi_buf_write_free(struct comedi_async *async,
8ae560a1 HS	263	unsigned int nbytes)
ea082fb1	264	{
d21af4cb HS	265	unsigned int allocated = comedi_buf_write_n_allocated(async);
d21af4cb HS	266
6166ce87	267	if (nbytes > allocated)
d21af4cb	268	nbytes = allocated;
6166ce87	269
ea082fb1 HS	270	async->buf_write_count += nbytes;
	271	async->buf_write_ptr += nbytes;
	272	comedi_buf_munge(async, async->buf_write_count - async->munge_count);
	273	if (async->buf_write_ptr >= async->prealloc_bufsz)
	274	async->buf_write_ptr %= async->prealloc_bufsz;
	275
	276	return nbytes;
	277	}
5660e742	278	EXPORT_SYMBOL_GPL(comedi_buf_write_free);
ea082fb1 HS	279
	280	unsigned int comedi_buf_read_n_available(struct comedi_async *async)
	281	{
	282	unsigned num_bytes;
	283
43f9137d	284	if (!async)
ea082fb1	285	return 0;
43f9137d	286
ea082fb1	287	num_bytes = async->munge_count - async->buf_read_count;
43f9137d HS	288
	289	/*
	290	* ensure the async buffer 'counts' are read before we
	291	* attempt to read data from the buffer
ea082fb1 HS	292	*/
ea082fb1 HS	293	smp_rmb();
43f9137d	294
ea082fb1 HS	295	return num_bytes;
ea082fb1 HS	296	}
5660e742	297	EXPORT_SYMBOL_GPL(comedi_buf_read_n_available);
ea082fb1 HS	298
ea082fb1 HS	299	/* allocates a chunk for the reader from filled (and munged) buffer space */
8ae560a1 HS	300	unsigned int comedi_buf_read_alloc(struct comedi_async *async,
8ae560a1 HS	301	unsigned int nbytes)
ea082fb1	302	{
034cbd17 HS	303	unsigned int available;
	304
	305	available = async->munge_count - async->buf_read_alloc_count;
	306	if (nbytes > available)
	307	nbytes = available;
	308
ea082fb1	309	async->buf_read_alloc_count += nbytes;
034cbd17 HS	310
	311	/*
	312	* ensure the async buffer 'counts' are read before we
	313	* attempt to read data from the read-alloc'ed buffer space
	314	*/
ea082fb1	315	smp_rmb();
034cbd17	316
ea082fb1 HS	317	return nbytes;
ea082fb1 HS	318	}
5660e742	319	EXPORT_SYMBOL_GPL(comedi_buf_read_alloc);
ea082fb1	320
5b2b64b7 HS	321	static unsigned int comedi_buf_read_n_allocated(struct comedi_async *async)
	322	{
	323	return async->buf_read_alloc_count - async->buf_read_count;
	324	}
	325
ea082fb1	326	/* transfers control of a chunk from reader to free buffer space */
8ae560a1 HS	327	unsigned int comedi_buf_read_free(struct comedi_async *async,
8ae560a1 HS	328	unsigned int nbytes)
ea082fb1	329	{
3abfa106 HS	330	unsigned int allocated;
	331
	332	/*
	333	* ensure data has been read out of buffer before
	334	* the async read count is incremented
	335	*/
ea082fb1	336	smp_mb();
3abfa106 HS	337
3abfa106 HS	338	allocated = comedi_buf_read_n_allocated(async);
215040e1	339	if (nbytes > allocated)
3abfa106	340	nbytes = allocated;
215040e1	341
ea082fb1 HS	342	async->buf_read_count += nbytes;
	343	async->buf_read_ptr += nbytes;
	344	async->buf_read_ptr %= async->prealloc_bufsz;
	345	return nbytes;
	346	}
5660e742	347	EXPORT_SYMBOL_GPL(comedi_buf_read_free);
ea082fb1 HS	348
	349	int comedi_buf_put(struct comedi_async *async, short x)
	350	{
47181eab	351	unsigned int n = __comedi_buf_write_alloc(async, sizeof(short), 1);
ea082fb1 HS	352
	353	if (n < sizeof(short)) {
	354	async->events \|= COMEDI_CB_ERROR;
	355	return 0;
	356	}
	357	(short )(async->prealloc_buf + async->buf_write_ptr) = x;
	358	comedi_buf_write_free(async, sizeof(short));
	359	return 1;
	360	}
5660e742	361	EXPORT_SYMBOL_GPL(comedi_buf_put);
ea082fb1 HS	362
	363	int comedi_buf_get(struct comedi_async async, short x)
	364	{
	365	unsigned int n = comedi_buf_read_n_available(async);
	366
	367	if (n < sizeof(short))
	368	return 0;
	369	comedi_buf_read_alloc(async, sizeof(short));
	370	x = (short *)(async->prealloc_buf + async->buf_read_ptr);
	371	comedi_buf_read_free(async, sizeof(short));
	372	return 1;
	373	}
5660e742	374	EXPORT_SYMBOL_GPL(comedi_buf_get);
ea082fb1 HS	375
	376	void comedi_buf_memcpy_to(struct comedi_async *async, unsigned int offset,
	377	const void *data, unsigned int num_bytes)
	378	{
	379	unsigned int write_ptr = async->buf_write_ptr + offset;
	380
	381	if (write_ptr >= async->prealloc_bufsz)
	382	write_ptr %= async->prealloc_bufsz;
	383
	384	while (num_bytes) {
	385	unsigned int block_size;
	386
	387	if (write_ptr + num_bytes > async->prealloc_bufsz)
	388	block_size = async->prealloc_bufsz - write_ptr;
	389	else
	390	block_size = num_bytes;
	391
	392	memcpy(async->prealloc_buf + write_ptr, data, block_size);
	393
	394	data += block_size;
	395	num_bytes -= block_size;
	396
	397	write_ptr = 0;
	398	}
	399	}
5660e742	400	EXPORT_SYMBOL_GPL(comedi_buf_memcpy_to);
ea082fb1 HS	401
	402	void comedi_buf_memcpy_from(struct comedi_async *async, unsigned int offset,
	403	void *dest, unsigned int nbytes)
	404	{
	405	void *src;
	406	unsigned int read_ptr = async->buf_read_ptr + offset;
	407
	408	if (read_ptr >= async->prealloc_bufsz)
	409	read_ptr %= async->prealloc_bufsz;
	410
	411	while (nbytes) {
	412	unsigned int block_size;
	413
	414	src = async->prealloc_buf + read_ptr;
	415
	416	if (nbytes >= async->prealloc_bufsz - read_ptr)
	417	block_size = async->prealloc_bufsz - read_ptr;
	418	else
	419	block_size = nbytes;
	420
	421	memcpy(dest, src, block_size);
	422	nbytes -= block_size;
	423	dest += block_size;
	424	read_ptr = 0;
	425	}
	426	}
5660e742	427	EXPORT_SYMBOL_GPL(comedi_buf_memcpy_from);