Re: [PATCH 20/32] Blackfin arch: dma_memcpy borken for > 64K

From: Pekka Enberg
Date: Mon May 21 2007 - 07:26:18 EST


Hi Bryan,

On 5/21/07, Bryan Wu <bryan.wu@xxxxxxxxxx> wrote:
-void *dma_memcpy(void *dest, const void *src, size_t size)
+void *_dma_memcpy(void *dest, const void *src, size_t size)

Minor nitpick: the established naming convention is two underscores, not one.

+void *dma_memcpy(void *dest, const void *src, size_t size)
+{
+ size_t bulk;
+ size_t rest;
+ void * addr;
+
+ bulk = (size >> 16) << 16;

I assume this is significantly faster on your architecture than:

bulk = size & ~0xFFFFUL;

which is more readable?

+ rest = size - bulk;
+ if (bulk)
+ _dma_memcpy(dest, src, bulk);
+ addr = _dma_memcpy(dest+bulk, src+bulk, rest);
+ return addr;

Does this work for 128K and up? Why?
-
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