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 <sound/memalloc.h>
 26
 27
 28/* table entries are align to 32 */
 29#define SGBUF_TBL_ALIGN		32
 30#define sgbuf_align_table(tbl)	ALIGN((tbl), SGBUF_TBL_ALIGN)
 31
 32int snd_free_sgbuf_pages(struct snd_dma_buffer *dmab)
 33{
 34	struct snd_sg_buf *sgbuf = dmab->private_data;
 35	struct snd_dma_buffer tmpb;
 36	int i;
 37
 38	if (! sgbuf)
 39		return -EINVAL;
 40
 41	if (dmab->area)
 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				return NULL;
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}