[ALSA] make the pxa2xx-ac97 module more robust against PXA27x bugs
[linux-2.6.git] / sound / arm / devdma.c
1 /*
2  *  linux/sound/arm/devdma.c
3  *
4  *  Copyright (C) 2003-2004 Russell King, All rights reserved.
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 version 2 as
8  * published by the Free Software Foundation.
9  *
10  *  ARM DMA shim for ALSA.
11  */
12 #include <linux/device.h>
13 #include <linux/dma-mapping.h>
14
15 #include <sound/driver.h>
16 #include <sound/core.h>
17 #include <sound/pcm.h>
18
19 #include "devdma.h"
20
21 void devdma_hw_free(struct device *dev, struct snd_pcm_substream *substream)
22 {
23         struct snd_pcm_runtime *runtime = substream->runtime;
24         struct snd_dma_buffer *buf = runtime->dma_buffer_p;
25
26         if (runtime->dma_area == NULL)
27                 return;
28
29         if (buf != &substream->dma_buffer) {
30                 dma_free_coherent(buf->dev.dev, buf->bytes, buf->area, buf->addr);
31                 kfree(runtime->dma_buffer_p);
32         }
33
34         snd_pcm_set_runtime_buffer(substream, NULL);
35 }
36
37 int devdma_hw_alloc(struct device *dev, struct snd_pcm_substream *substream, size_t size)
38 {
39         struct snd_pcm_runtime *runtime = substream->runtime;
40         struct snd_dma_buffer *buf = runtime->dma_buffer_p;
41         int ret = 0;
42
43         if (buf) {
44                 if (buf->bytes >= size)
45                         goto out;
46                 devdma_hw_free(dev, substream);
47         }
48
49         if (substream->dma_buffer.area != NULL && substream->dma_buffer.bytes >= size) {
50                 buf = &substream->dma_buffer;
51         } else {
52                 buf = kmalloc(sizeof(struct snd_dma_buffer), GFP_KERNEL);
53                 if (!buf)
54                         goto nomem;
55
56                 buf->dev.type = SNDRV_DMA_TYPE_DEV;
57                 buf->dev.dev = dev;
58                 buf->area = dma_alloc_coherent(dev, size, &buf->addr, GFP_KERNEL);
59                 buf->bytes = size;
60                 buf->private_data = NULL;
61
62                 if (!buf->area)
63                         goto free;
64         }
65         snd_pcm_set_runtime_buffer(substream, buf);
66         ret = 1;
67  out:
68         runtime->dma_bytes = size;
69         return ret;
70
71  free:
72         kfree(buf);
73  nomem:
74         return -ENOMEM;
75 }
76
77 int devdma_mmap(struct device *dev, struct snd_pcm_substream *substream, struct vm_area_struct *vma)
78 {
79         struct snd_pcm_runtime *runtime = substream->runtime;
80         return dma_mmap_coherent(dev, vma, runtime->dma_area, runtime->dma_addr, runtime->dma_bytes);
81 }