On Tue, May 7, 2013 at 5:48 AM, Hervé Poussineau <hpous...@reactos.org> wrote: > Andreas Färber a écrit : > >> Am 06.05.2013 22:57, schrieb Hervé Poussineau: >>> >>> Alexander Graf a écrit : >>>> >>>> On 05/03/2013 07:57 AM, Hervé Poussineau wrote: >>>>> >>>>> Alexander Graf a écrit : >>>>>> >>>>>> Am 02.05.2013 um 22:08 schrieb Hervé Poussineau >>>>>> <hpous...@reactos.org>: >>>>>> >>>>>>> Non-contiguous I/O is not implemented. >>>>>>> >>>>>>> There is also somewhere a bug in the memory controller, which means >>>>>>> that some real firmwares may not detect the correct amount of memory. >>>>>>> This can be bypassed by adding '-m 1G' on the command line. >>>>>>> >>>>>>> Add x-auto-conf property, to automatically configure the memory >>>>>>> controller at startup. This will be required by OpenBIOS, which >>>>>>> doesn't know how to do it. >>>>>> >>>>>> Why not teach it? I'd prefer to see that logic in firmware. >>>>> >>>>> Me too, but I'm not confident enough in my capabilities to do it. >>>> >>>> Huh? Why not? Most of the device initialization code in OpenBIOS >>>> happens in C, so you don't even have to touch Forth code :). >>>> >>>>> Autoconfiguration is only in one place of the code, so I think it can >>>>> be removed easily once OpenBIOS has this logic. >>>> >>>> I'd prefer if we could come up with a clean model from the start. It >>>> really shouldn't be hard at all. >>>> >>> I thought that for all other usages of OpenBIOS in QEMU, RAM was >>> supposed to be available as soon as machine was powered on. >>> >>> However, I checked OpenBIOS code: >>> One of the first things done in arch/ppc/qemu/start.S is to copy the >>> exception vectors. So, I should add code before it to detect memory >>> controller, detect ram size and configure memory controller? >> >> >> No. Why? QEMU does not depend on the memory controller being >> initialized, only the OS might expect some registers to be filled in. So >> you should look at or add the MPC105 PHB initialization hook in >> OpenBIOS' PCI code, long after the memory is set up. > > > OpenBIOS depends of memory being available (at least the first KB/MB) even > at its very startup, in arch/ppc/qemu/start.S. PCI initialization code comes > much later.
OpenBIOS for Sparc32 and Sparc64 does not use RAM before RAM size has been read from fw_cfg. A check for QEMU signature is done and machine ID is also read before that. arch/sparc32/entry.S arch/sparc64/entry.S It should be easy to change PPC to check the machine ID before accessing RAM. > At boot, MPC105 datasheet says that memory controller is not configured, ie > you have to not use RAM in OpenBIOS before PCI initialization. The memory controller should be initialized much earlier than PCI. > > For other PPC targets (mac99, g3beige) using OpenBIOS, RAM is accessible at > startup, so that's not a problem for OpenBIOS. > > So, no, QEMU does not depend of the memory controller being initialized, but > OpenBIOS depends of the RAM being accessible ways before PCI initialization. > I don't speak of the OS which might (or might not) expect some registers to > be filled in. > x-auto-conf property correctly sets some registers, so that memory is > available at startup (like on mac99, g3beige emulations). > > Hervé >
