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-rw-r--r--sound/core/sgbuf.c164
1 files changed, 164 insertions, 0 deletions
diff --git a/sound/core/sgbuf.c b/sound/core/sgbuf.c
new file mode 100644
index 000000000..84fffabdd
--- /dev/null
+++ b/sound/core/sgbuf.c
@@ -0,0 +1,164 @@
+/*
+ * 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 <linux/export.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;
+
+ 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)
+ goto _failed;
+ 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;
+}
+
+/*
+ * compute the max chunk size with continuous pages on sg-buffer
+ */
+unsigned int snd_sgbuf_get_chunk_size(struct snd_dma_buffer *dmab,
+ unsigned int ofs, unsigned int size)
+{
+ struct snd_sg_buf *sg = dmab->private_data;
+ unsigned int start, end, pg;
+
+ start = ofs >> PAGE_SHIFT;
+ end = (ofs + size - 1) >> PAGE_SHIFT;
+ /* check page continuity */
+ pg = sg->table[start].addr >> PAGE_SHIFT;
+ for (;;) {
+ start++;
+ if (start > end)
+ break;
+ pg++;
+ if ((sg->table[start].addr >> PAGE_SHIFT) != pg)
+ return (start << PAGE_SHIFT) - ofs;
+ }
+ /* ok, all on continuous pages */
+ return size;
+}
+EXPORT_SYMBOL(snd_sgbuf_get_chunk_size);