Messages in this thread | | | Date | Fri, 30 Sep 2011 21:17:07 +0530 | Subject | Re: [PATCHv4] DMAEngine: Define interleaved transfer request api | From | Jassi Brar <> |
| |
On 29 September 2011 16:47, Vinod Koul <vinod.koul@intel.com> wrote: > On Wed, 2011-09-28 at 20:45 +0530, Jassi Brar wrote: >> >> +enum xfer_direction { >> >> + MEM_TO_MEM, >> >> + MEM_TO_DEV, >> >> + DEV_TO_MEM, >> >> + DEV_TO_DEV, >> > Use/update dma_data_direction. >> dma_data_direction is the mapping attribute of a buffer. >> While that info is what some dmac driver might need ultimately, our >> main aim here is to tell exactly if Src and Dst is Memory or a >> device's FIFO. >> >> Mapping attribute of src/dst buffers could be very well deducted from >> xfer_direction, but dma_data_direction isn't meant to tell if Src and >> Dst is Mem or FIFO. >> Also, for (SLAVE && !src_inc && !dst_inc) we need to disambiguate >> three options Mem->Fifo, Fifo->Mem, *Fifo->Fifo*(not impossible) >> So while using dma_data_direction would work today, that sure is hacky >> and not future-proof. > That is why I said use/update, you missed the update part. > > One way would be to use direction field with new flag indicating if its > memory or device transfer, otherwise you can expand this enum. > > Point is few things are already there so improve upon it rather than > have two structures in kernel doing similar things... > I don't think dma_data_direction should be messed with here. Or I am just being ignorant, in that case please do suggest how do you want dma_data_direction "updated" ? -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
| |