Hello, I'm working a new DMA hardware for PPC processors. The processor is a 32 bit architecture having 40 bit physical address space. So we need the 32 bit processor code base but we want the type dma_addr_t to represent 64 bit data, without enabling the CONFIG_PPC64 flag. We want to use the Linux generic DMA layer to offload DMA operations to the hw and the Linux code path goes through function dma_async_memcpy_buf_to_buf and then dma_map_single. Currently the dma_map_single function has 2 versions based upon CONFIG_PPC64 defined or not. Is it possible to reuse the CONFIG_PPC64 based code only pertaining to DMA by doing the following: Add a new flag called CONFIG_DMA64 along with CONFIG_PPC64 and __powerpc64__ flags, enabling our code to use the generic DMA layer with 64 bit data type for dma_addr_t. With the above modification, the function dma_map_single starts returning 64 bit data type instead of 32. Do you have any comments or suggestions ? -thanks TT _______________________________________________ Linuxppc-embedded mailing list [email protected] https://ozlabs.org/mailman/listinfo/linuxppc-embedded
