That case, device-specific coherent memory allocation, is handled at dma_alloc_coherent in arm_dma_alloc.
__dma_alloc handles only general coherent memory allocation.
I'm sorry missing mention about it.
2014-05-20 오후 3:52, Joonsoo Kim 쓴 글:
On Tue, May 20, 2014 at 02:57:47PM +0900, Gioh Kim wrote:
Thanks for your advise, Michal Nazarewicz.
Having discuss with Joonsoo, I'm adding fallback allocation after __alloc_from_contiguous().
The fallback allocation works if CMA kernel options is turned on but CMA size is zero.
Hello, Gioh.
I also mentioned the case where devices have their specific cma_area.
It means that this device needs memory with some contraint.
Although I'm not familiar with DMA infrastructure, I think that
we should handle this case.
How about below patch?
------------>8----------------
diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c
index 6b00be1..4023434 100644
--- a/arch/arm/mm/dma-mapping.c
+++ b/arch/arm/mm/dma-mapping.c
@@ -379,7 +379,7 @@ static int __init atomic_pool_init(void)
unsigned long *bitmap;
struct page *page;
struct page **pages;
- void *ptr;
+ void *ptr = NULL;
int bitmap_size = BITS_TO_LONGS(nr_pages) * sizeof(long);
bitmap = kzalloc(bitmap_size, GFP_KERNEL);
@@ -393,7 +393,8 @@ static int __init atomic_pool_init(void)
if (IS_ENABLED(CONFIG_DMA_CMA))
ptr = __alloc_from_contiguous(NULL, pool->size, prot, &page,
atomic_pool_init);
- else
+
+ if (!ptr)
ptr = __alloc_remap_buffer(NULL, pool->size, gfp, prot, &page,
atomic_pool_init);
if (ptr) {
@@ -701,10 +702,22 @@ static void *__dma_alloc(struct device *dev, size_t size, dma_addr_t *handle,
addr = __alloc_simple_buffer(dev, size, gfp, &page);
else if (!(gfp & __GFP_WAIT))
addr = __alloc_from_pool(size, &page);
- else if (!IS_ENABLED(CONFIG_DMA_CMA))
- addr = __alloc_remap_buffer(dev, size, gfp, prot, &page, caller);
- else
- addr = __alloc_from_contiguous(dev, size, prot, &page, caller);
+ else {
+ if (IS_ENABLED(CONFIG_DMA_CMA)) {
+ addr = __alloc_from_contiguous(dev, size, prot,
+ &page, caller);
+ /*
+ * Device specific cma_area means that
+ * this device needs memory with some contraint.
+ * So, we can't fall through general remap allocation.
+ */
+ if (!addr && dev && dev->cma_area)
+ return NULL;
+ }
+
+ addr = __alloc_remap_buffer(dev, size, gfp, prot,
+ &page, caller);
+ }
if (addr)
*handle = pfn_to_dma(dev, page_to_pfn(page));
--
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