1/*
2 * Scatter-Gather buffer
3 *
4 *  Copyright (c) by Takashi Iwai <tiwai@suse.de>
5 *
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.
10 *
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.
15 *
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., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
19 *
20 */
21
22#include <linux/slab.h>
23#include <linux/mm.h>
24#include <linux/vmalloc.h>
25#include <linux/export.h>
26#include <sound/memalloc.h>
27
28
29/* table entries are align to 32 */
30#define SGBUF_TBL_ALIGN		32
31#define sgbuf_align_table(tbl)	ALIGN((tbl), SGBUF_TBL_ALIGN)
32
33int snd_free_sgbuf_pages(struct snd_dma_buffer *dmab)
34{
35	struct snd_sg_buf *sgbuf = dmab->private_data;
36	struct snd_dma_buffer tmpb;
37	int i;
38
39	if (! sgbuf)
40		return -EINVAL;
41
42	vunmap(dmab->area);
43	dmab->area = NULL;
44
45	tmpb.dev.type = SNDRV_DMA_TYPE_DEV;
46	tmpb.dev.dev = sgbuf->dev;
47	for (i = 0; i < sgbuf->pages; i++) {
48		if (!(sgbuf->table[i].addr & ~PAGE_MASK))
49			continue; /* continuous pages */
50		tmpb.area = sgbuf->table[i].buf;
51		tmpb.addr = sgbuf->table[i].addr & PAGE_MASK;
52		tmpb.bytes = (sgbuf->table[i].addr & ~PAGE_MASK) << PAGE_SHIFT;
53		snd_dma_free_pages(&tmpb);
54	}
55
56	kfree(sgbuf->table);
57	kfree(sgbuf->page_table);
58	kfree(sgbuf);
59	dmab->private_data = NULL;
60
61	return 0;
62}
63
64#define MAX_ALLOC_PAGES		32
65
66void *snd_malloc_sgbuf_pages(struct device *device,
67			     size_t size, struct snd_dma_buffer *dmab,
68			     size_t *res_size)
69{
70	struct snd_sg_buf *sgbuf;
71	unsigned int i, pages, chunk, maxpages;
72	struct snd_dma_buffer tmpb;
73	struct snd_sg_page *table;
74	struct page **pgtable;
75
76	dmab->area = NULL;
77	dmab->addr = 0;
78	dmab->private_data = sgbuf = kzalloc(sizeof(*sgbuf), GFP_KERNEL);
79	if (! sgbuf)
80		return NULL;
81	sgbuf->dev = device;
82	pages = snd_sgbuf_aligned_pages(size);
83	sgbuf->tblsize = sgbuf_align_table(pages);
84	table = kcalloc(sgbuf->tblsize, sizeof(*table), GFP_KERNEL);
85	if (!table)
86		goto _failed;
87	sgbuf->table = table;
88	pgtable = kcalloc(sgbuf->tblsize, sizeof(*pgtable), GFP_KERNEL);
89	if (!pgtable)
90		goto _failed;
91	sgbuf->page_table = pgtable;
92
93	/* allocate pages */
94	maxpages = MAX_ALLOC_PAGES;
95	while (pages > 0) {
96		chunk = pages;
97		/* don't be too eager to take a huge chunk */
98		if (chunk > maxpages)
99			chunk = maxpages;
100		chunk <<= PAGE_SHIFT;
101		if (snd_dma_alloc_pages_fallback(SNDRV_DMA_TYPE_DEV, device,
102						 chunk, &tmpb) < 0) {
103			if (!sgbuf->pages)
104				goto _failed;
105			if (!res_size)
106				goto _failed;
107			size = sgbuf->pages * PAGE_SIZE;
108			break;
109		}
110		chunk = tmpb.bytes >> PAGE_SHIFT;
111		for (i = 0; i < chunk; i++) {
112			table->buf = tmpb.area;
113			table->addr = tmpb.addr;
114			if (!i)
115				table->addr |= chunk; /* mark head */
116			table++;
117			*pgtable++ = virt_to_page(tmpb.area);
118			tmpb.area += PAGE_SIZE;
119			tmpb.addr += PAGE_SIZE;
120		}
121		sgbuf->pages += chunk;
122		pages -= chunk;
123		if (chunk < maxpages)
124			maxpages = chunk;
125	}
126
127	sgbuf->size = size;
128	dmab->area = vmap(sgbuf->page_table, sgbuf->pages, VM_MAP, PAGE_KERNEL);
129	if (! dmab->area)
130		goto _failed;
131	if (res_size)
132		*res_size = sgbuf->size;
133	return dmab->area;
134
135 _failed:
136	snd_free_sgbuf_pages(dmab); /* free the table */
137	return NULL;
138}
139
140/*
141 * compute the max chunk size with continuous pages on sg-buffer
142 */
143unsigned int snd_sgbuf_get_chunk_size(struct snd_dma_buffer *dmab,
144				      unsigned int ofs, unsigned int size)
145{
146	struct snd_sg_buf *sg = dmab->private_data;
147	unsigned int start, end, pg;
148
149	start = ofs >> PAGE_SHIFT;
150	end = (ofs + size - 1) >> PAGE_SHIFT;
151	/* check page continuity */
152	pg = sg->table[start].addr >> PAGE_SHIFT;
153	for (;;) {
154		start++;
155		if (start > end)
156			break;
157		pg++;
158		if ((sg->table[start].addr >> PAGE_SHIFT) != pg)
159			return (start << PAGE_SHIFT) - ofs;
160	}
161	/* ok, all on continuous pages */
162	return size;
163}
164EXPORT_SYMBOL(snd_sgbuf_get_chunk_size);
165