linux-4.4.1/snd_dma_alloc_pages() の履歴(No.1)

• 履歴一覧
• 差分 を表示
• 現在との差分 を表示
• ソース を表示
• linux-4.4.1/snd_dma_alloc_pages() へ行く。
  • 1 (2017-03-29 (水) 10:58:55)
  • 2 (2017-03-29 (水) 11:00:33)

参照元†

• linux-4.4.1/preallocate_pcm_pages()

説明†

• パス: linux-4.4.1/sound/core/memalloc.c

• FIXME: これは何？
  • 説明

引数†

• int type
• 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†

• int

参考†

実装†

/**
 * 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;
}

コメント†