Dan Malek wrote: > > On Jun 3, 2004, at 5:06 AM, Pantelis Antoniou wrote: > > >> 1. dma_map_single finally calls virt_to_bus, which is simplified >> to: >> return (unsigned long)address - KERNELBASE + PCI_DRAM_OFFSET; >> >> PCI_DRAM_OFFSET is defined to be pci_dram_offset. >> Typically it is set be 0 for most arches without pci. > > > It's typically set to zero for all architectures. > >> How could we overide it with a constant 0 so that we avoid the >> memory access? > > > What memory access? > Oops, correct :)
>> 2. How soon in the init sequence could we call dma_alloc_consistent? > > > Not soon enough. > >> For example when setting up a serial console on 8xx I need memory >> for the fifos, and I have to revert in using m8xx_hostalloc which >> IMO should be already dead. > > > As you pointed out, that is going to have to stay for a while. The > CPM and peripherals must do DMA long before the generic > supporting functions are ready. > >> If we could arrange for consistent_alloc to be able to operate with >> a fixed memory area until the memory initialization is complete >> it would make my life much easier and we could finally kill >> m8xx_hostalloc & friends. > > > I don't think it is worth the complication. > Let me work on it a bit... > > -- Dan > > > Regards Pantelis ** Sent via the linuxppc-embedded mail list. See http://lists.linuxppc.org/
