1 files changed, 138 insertions, 0 deletions
diff --git a/sound/core/sgbuf.c b/sound/core/sgbuf.c
new file mode 100644
index 00000000..4e7ec2b4
--- /dev/null
+++ b/sound/core/sgbuf.c
@@ -0,0 +1,138 @@
+/*
+ * Scatter-Gather buffer
+ *
+ *  Copyright (c) by Takashi Iwai <tiwai@suse.de>
+ *
+ *   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., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
+ *
+ */
+
+#include <linux/slab.h>
+#include <linux/mm.h>
+#include <linux/vmalloc.h>
+#include <sound/memalloc.h>
+
+
+/* table entries are align to 32 */
+#define SGBUF_TBL_ALIGN		32
+#define sgbuf_align_table(tbl)	ALIGN((tbl), SGBUF_TBL_ALIGN)
+
+int snd_free_sgbuf_pages(struct snd_dma_buffer *dmab)
+{
+	struct snd_sg_buf *sgbuf = dmab->private_data;
+	struct snd_dma_buffer tmpb;
+	int i;
+
+	if (! sgbuf)
+		return -EINVAL;
+
+	if (dmab->area)
+		vunmap(dmab->area);
+	dmab->area = NULL;
+
+	tmpb.dev.type = SNDRV_DMA_TYPE_DEV;
+	tmpb.dev.dev = sgbuf->dev;
+	for (i = 0; i < sgbuf->pages; i++) {
+		if (!(sgbuf->table[i].addr & ~PAGE_MASK))
+			continue; /* continuous pages */
+		tmpb.area = sgbuf->table[i].buf;
+		tmpb.addr = sgbuf->table[i].addr & PAGE_MASK;
+		tmpb.bytes = (sgbuf->table[i].addr & ~PAGE_MASK) << PAGE_SHIFT;
+		snd_dma_free_pages(&tmpb);
+	}
+
+	kfree(sgbuf->table);
+	kfree(sgbuf->page_table);
+	kfree(sgbuf);
+	dmab->private_data = NULL;
+	
+	return 0;
+}
+
+#define MAX_ALLOC_PAGES		32
+
+void *snd_malloc_sgbuf_pages(struct device *device,
+			     size_t size, struct snd_dma_buffer *dmab,
+			     size_t *res_size)
+{
+	struct snd_sg_buf *sgbuf;
+	unsigned int i, pages, chunk, maxpages;
+	struct snd_dma_buffer tmpb;
+	struct snd_sg_page *table;
+	struct page **pgtable;
+
+	dmab->area = NULL;
+	dmab->addr = 0;
+	dmab->private_data = sgbuf = kzalloc(sizeof(*sgbuf), GFP_KERNEL);
+	if (! sgbuf)
+		return NULL;
+	sgbuf->dev = device;
+	pages = snd_sgbuf_aligned_pages(size);
+	sgbuf->tblsize = sgbuf_align_table(pages);
+	table = kcalloc(sgbuf->tblsize, sizeof(*table), GFP_KERNEL);
+	if (!table)
+		goto _failed;
+	sgbuf->table = table;
+	pgtable = kcalloc(sgbuf->tblsize, sizeof(*pgtable), GFP_KERNEL);
+	if (!pgtable)
+		goto _failed;
+	sgbuf->page_table = pgtable;
+
+	/* allocate pages */
+	maxpages = MAX_ALLOC_PAGES;
+	while (pages > 0) {
+		chunk = pages;
+		/* don't be too eager to take a huge chunk */
+		if (chunk > maxpages)
+			chunk = maxpages;
+		chunk <<= PAGE_SHIFT;
+		if (snd_dma_alloc_pages_fallback(SNDRV_DMA_TYPE_DEV, device,
+						 chunk, &tmpb) < 0) {
+			if (!sgbuf->pages)
+				return NULL;
+			if (!res_size)
+				goto _failed;
+			size = sgbuf->pages * PAGE_SIZE;
+			break;
+		}
+		chunk = tmpb.bytes >> PAGE_SHIFT;
+		for (i = 0; i < chunk; i++) {
+			table->buf = tmpb.area;
+			table->addr = tmpb.addr;
+			if (!i)
+				table->addr |= chunk; /* mark head */
+			table++;
+			*pgtable++ = virt_to_page(tmpb.area);
+			tmpb.area += PAGE_SIZE;
+			tmpb.addr += PAGE_SIZE;
+		}
+		sgbuf->pages += chunk;
+		pages -= chunk;
+		if (chunk < maxpages)
+			maxpages = chunk;
+	}
+
+	sgbuf->size = size;
+	dmab->area = vmap(sgbuf->page_table, sgbuf->pages, VM_MAP, PAGE_KERNEL);
+	if (! dmab->area)
+		goto _failed;
+	if (res_size)
+		*res_size = sgbuf->size;
+	return dmab->area;
+
+ _failed:
+	snd_free_sgbuf_pages(dmab); /* free the table */
+	return NULL;
+}