pci_single_map for large buffer????

Anton Blanchard anton at samba.org
Sat Aug 9 01:10:00 EST 2003


> Is there any limit on size of buffer that
> "pci_map_single" can  map on linux ppc64 2.4.19
> kernels????  For me pci_map_single is failing
> if I map a buffer of size more than 4K. Please
> mail me the pointers on how to map buffers of large
> size.

Yes there is a maximum size, in include/asm-ppc64/pci_dma.h:

 * NUM_TCE_LEVELS defines the largest contiguous block
 * of dma (tce) space we can get.  NUM_TCE_LEVELS = 10
 * allows up to 2**9 pages (512 * 4096) = 2 MB
#define NUM_TCE_LEVELS 10


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