linux-4.4.1/snd_dma_alloc_pages() の変更点

• 追加された行はこの色です。
• 削除された行はこの色です。
• linux-4.4.1/snd_dma_alloc_pages() へ行く。
• linux-4.4.1/snd_dma_alloc_pages() の差分を削除

*参照元 [#m915da3d]
#backlinks

*説明 [#hedbbced]
-パス: [[linux-4.4.1/sound/core/memalloc.c]]

-FIXME: これは何？
--説明


type によって呼ばれるメモリ確保の関数が異なる。

-SNDRV_DMA_TYPE_CONTINUOUS
--snd_malloc_pages()
-SNDRV_DMA_TYPE_DEV_IRAM
--snd_malloc_dev_iram()
-SNDRV_DMA_TYPE_DEV
--snd_malloc_dev_pages()
-SNDRV_DMA_TYPE_DEV_SG
--snd_malloc_sgbuf_pages()


**引数 [#q372a1b2]
-int type
--
--確保する DMA バッファの種類
-struct device *device
--
--[[linux-4.4.1/device]]
-size_t size
--
-struct snd_dma_buffer *dmab
--
--[[linux-4.4.1/snd_dma_buffer]]


**返り値 [#xfdd4bb7]
-int
--
--0 なら成功、負のエラー値なら失敗。


**参考 [#b4aedf2c]


*実装 [#m61fe59c]
 /**
  * snd_dma_alloc_pages - allocate the buffer area according to the given type
  * @type: the DMA buffer type
  * @device: the device pointer
  * @size: the buffer size to allocate
  * @dmab: buffer allocation record to store the allocated data
  *
  * Calls the memory-allocator function for the corresponding
  * buffer type.
  *
  * Return: Zero if the buffer with the given size is allocated successfully,
  * otherwise a negative value on error.
  */
 int snd_dma_alloc_pages(int type, struct device *device, size_t size,
                         struct snd_dma_buffer *dmab)
 {
         if (WARN_ON(!size))
                 return -ENXIO;
         if (WARN_ON(!dmab))
                 return -ENXIO;
 
-
--[[linux-4.4.1/WARN_ON()]]

         dmab->dev.type = type;
         dmab->dev.dev = device;
         dmab->bytes = 0;
         switch (type) {
         case SNDRV_DMA_TYPE_CONTINUOUS:
                 dmab->area = snd_malloc_pages(size,
                                         (__force gfp_t)(unsigned long)device);
                 dmab->addr = 0;
                 break;
-
--[[linux-4.4.1/snd_malloc_pages()]]
-
--[[linux-4.4.1/__force]]
-
--[[linux-4.4.1/gfp_t]]

 #ifdef CONFIG_HAS_DMA
 #ifdef CONFIG_GENERIC_ALLOCATOR
-
--[[linux-4.4.1/CONFIG_HAS_DMA]]
-
--[[linux-4.4.1/CONFIG_GENERIC_ALLOCATOR]]

         case SNDRV_DMA_TYPE_DEV_IRAM:
                 snd_malloc_dev_iram(dmab, size);
                 if (dmab->area)
                         break;
-
--[[linux-4.4.1/snd_malloc_dev_iram()]]

                 /* Internal memory might have limited size and no enough space,
                  * so if we fail to malloc, try to fetch memory traditionally.
                  */
                 dmab->dev.type = SNDRV_DMA_TYPE_DEV;
 #endif /* CONFIG_GENERIC_ALLOCATOR */
         case SNDRV_DMA_TYPE_DEV:
                 dmab->area = snd_malloc_dev_pages(device, size, &dmab->addr);
                 break;
-
--[[linux-4.4.1/snd_malloc_dev_pages()]]

 #endif
 #ifdef CONFIG_SND_DMA_SGBUF
-
--[[linux-4.4.1/CONFIG_SND_DMA_SGBUF]]

         case SNDRV_DMA_TYPE_DEV_SG:
                 snd_malloc_sgbuf_pages(device, size, dmab, NULL);
                 break;
-
--[[linux-4.4.1/snd_malloc_sgbuf_pages()]]

 #endif
         default:
                 pr_err("snd-malloc: invalid device type %d\n", type);
                 dmab->area = NULL;
                 dmab->addr = 0;
                 return -ENXIO;
-
--[[linux-4.4.1/pr_err()]]

         }
         if (! dmab->area)
                 return -ENOMEM;
         dmab->bytes = size;
         return 0;
 }
 
 ...
 
 EXPORT_SYMBOL(snd_dma_alloc_pages);
-
--[[linux-4.4.1/EXPORT_SYMBOL()]]


*コメント [#i991a653]