On Wed, Feb 4, 2009 at 12:26, Hennerich, Michael wrote: >>On Wed, Feb 4, 2009 at 11:54, Hennerich, Michael wrote: >>>>where in the HRM do you see it saying "32-bit dma is not supported" ? >>> >>> I don't think it's explicitly written in the NFC chapter of the HRM. >>> But it's a matter of fact that the DMA DAB is 16-bit on BF52x. >>> >>> From the PHRM: >>> >>> "The 16-bit DMA Access Bus (DAB) connects the DMA controller to the >>> on-chip peripherals, PPI, SPI, Ethernet MAC, the SPORTs, NFC, >>> HOSTDP and the UARTs." >>> >>> 32-bit DMA won't work! >> >>the sport controller supports 32bit dma (and our drivers are using >>it). same goes for ethernet mac. > > Well right. > > Some peripherals support 32-bit DMA over an 16-bit DAB (taking 2x > cycles) , some not. > > NFC is one that doesn't support this. > > Whole story - Cliff skyped me this morning about the BF52x NFC DMA > problem. > In return I called Andrew C. and asked him about the NFC and associated > software differences between NFC on 54x and 52x. > > Straight came the answer BF52x DMA must be WDSIZE_16 !!!
which is fine, but now i know i need to hassle the docs guys to make sure this is clearly noted in our HRMs do you know which peripherals cannot work with 32bit other than the NFC ? -mike _______________________________________________ Linux-kernel-commits mailing list [email protected] http://blackfin.uclinux.org/mailman/listinfo/linux-kernel-commits
