V4L/DVB (6085): cx88-alsa: Fix mmap support

The driver has long claimed to support mmap, but it didn't work at all.  Some
of the dma buffer parameters weren't set, and since video_buf uses vmalloc to
allocate the buffer, a page callback is needed too.

Signed-off-by: Trent Piepho <xyzzy@speakeasy.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>

1 files changed, 14 insertions, 0 deletions

diff --git a/drivers/media/video/cx88/cx88-alsa.c b/drivers/media/video/cx88/cx88-alsa.c
index ac317fb856e4..85d632224f3a 100644
--- a/drivers/media/video/cx88/cx88-alsa.c
+++ b/drivers/media/video/cx88/cx88-alsa.c
@@ -28,6 +28,7 @@
 #include <linux/init.h>
 #include <linux/device.h>
 #include <linux/interrupt.h>
+#include <linux/vmalloc.h>
 #include <linux/dma-mapping.h>
 #include <linux/pci.h>
 
@@ -423,6 +424,8 @@ static int snd_cx88_hw_params(struct snd_pcm_substream * substream,
         chip->dma_risc = buf->vb.dma;
 
         substream->runtime->dma_area = chip->dma_risc.vmalloc;
+        substream->runtime->dma_bytes = chip->dma_size;
+        substream->runtime->dma_addr = 0;
         return 0;
 
 error:
@@ -500,6 +503,16 @@ static snd_pcm_uframes_t snd_cx88_pointer(struct snd_pcm_substream *substream)
 }
 
 /*
+ * page callback (needed for mmap)
+ */
+static struct page *snd_cx88_page(struct snd_pcm_substream *substream,
+                                unsigned long offset)
+{
+        void *pageptr = substream->runtime->dma_area + offset;
+        return vmalloc_to_page(pageptr);
+}
+
+/*
  * operators
  */
 static struct snd_pcm_ops snd_cx88_pcm_ops = {
@@ -511,6 +524,7 @@ static struct snd_pcm_ops snd_cx88_pcm_ops = {
         .prepare = snd_cx88_prepare,
         .trigger = snd_cx88_card_trigger,
         .pointer = snd_cx88_pointer,
+        .page = snd_cx88_page,
 };
 
 /*