参照元†
- struct device *dev
- size_t size
- dma_addr_t *handle
- gfp_t gfp
- pgprot_t prot
- bool is_coherent
- struct dma_attrs *attrs
- const void *caller
返り値†
static void *__dma_alloc(struct device *dev, size_t size, dma_addr_t *handle,
gfp_t gfp, pgprot_t prot, bool is_coherent,
struct dma_attrs *attrs, const void *caller)
{
u64 mask = get_coherent_dma_mask(dev);
struct page *page = NULL;
void *addr;
bool want_vaddr;
#ifdef CONFIG_DMA_API_DEBUG
u64 limit = (mask + 1) & ~mask;
if (limit && size >= limit) {
dev_warn(dev, "coherent allocation too big (requested %#x mask %#llx)\n",
size, mask);
return NULL;
}
#endif
if (!mask)
return NULL;
if (mask < 0xffffffffULL)
gfp |= GFP_DMA;
/*
* Following is a work-around (a.k.a. hack) to prevent pages
* with __GFP_COMP being passed to split_page() which cannot
* handle them. The real problem is that this flag probably
* should be 0 on ARM as it is not supported on this
* platform; see CONFIG_HUGETLBFS.
*/
gfp &= ~(__GFP_COMP);
*handle = DMA_ERROR_CODE;
size = PAGE_ALIGN(size);
want_vaddr = !dma_get_attr(DMA_ATTR_NO_KERNEL_MAPPING, attrs);
if (nommu())
addr = __alloc_simple_buffer(dev, size, gfp, &page);
else if (dev_get_cma_area(dev) && (gfp & __GFP_DIRECT_RECLAIM))
addr = __alloc_from_contiguous(dev, size, prot, &page,
caller, want_vaddr);
else if (is_coherent)
addr = __alloc_simple_buffer(dev, size, gfp, &page);
else if (!gfpflags_allow_blocking(gfp))
addr = __alloc_from_pool(size, &page);
else
addr = __alloc_remap_buffer(dev, size, gfp, prot, &page,
caller, want_vaddr);
if (page)
*handle = pfn_to_dma(dev, page_to_pfn(page));
return want_vaddr ? addr : page;
}
コメント†