vdma_alloc
extern unsigned long vdma_alloc(unsigned long paddr, unsigned long size);
vdma_alloc(CPHYSADDR(mem), size); /* XXX error checking */
EXPORT_SYMBOL(vdma_alloc);
*dma_handle = vdma_alloc(virt_to_phys(ret), size);
return vdma_alloc(phys, size);
sg->dma_address = vdma_alloc(sg_phys(sg), sg->length);