ALSA: Make snd_sgbuf_get_{ptr|addr}() available for non-SG cases
Passing struct snd_dma_buffer pointer instead, so that they work no
matter whether real SG buffer is used or not.
This is a preliminary work for the HD-audio DSP loader code.
Signed-off-by: Ian Minett <ian_minett@creativelabs.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
diff --git a/sound/core/sgbuf.c b/sound/core/sgbuf.c
index d0f0035..0a41850 100644
--- a/sound/core/sgbuf.c
+++ b/sound/core/sgbuf.c
@@ -22,6 +22,7 @@
#include <linux/slab.h>
#include <linux/mm.h>
#include <linux/vmalloc.h>
+#include <linux/export.h>
#include <sound/memalloc.h>
@@ -136,3 +137,29 @@
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);