On Wed, Jun 30, 2004 at 12:49:32AM +0200, Ralf Baechle wrote: > On Tue, Jun 29, 2004 at 03:13:13PM -0700, Jun Sun wrote: > > > > > The NEC DDB Vrc-5074 (and probably the other DDB variants as well) has one > > > > serial port in the Nile 4 host bridge, and 2 serial ports in the Super I/O. > > > > > > > > To me it sounds the most logical if the one in the Nile 4 is ttyS0. > > > > > > Then we need to find a way to make the order configurable somehow. > > > > This is why I favor run-time serial port configuration. My view > > (maybe a little dramatic) is to remove all static serial port definition > > and push them into board setup routine. asm/serial.h only needs > > to define the number serial lines, which itself could be configurable. > > <asm/serial.h> is on it's way out of the kernel - it's only a question of > time until either the current maintainer of the serial driver or somebody > with more time at hands will eleminate it. And serial.h was always only > meant to handle the kind of serial interfaces of which you just have to > know that they're there because probing for it isn't possible. Something > which these days is getting increasingly more rare thanks to PCI. > > What I really wouldn't like to see is the runtime registration for all > the legacy serial stuff that possibly could be plugged into some board > be duplicated into half a dozen of systems ... > No fear really. You can still provide STD_SERIAL_PORT in the asm/serial.h where each individual board simply does a registration for each line defined there. You might even provide some inline function for doing so in asm/serial.h. The big advantage of this scheme is that the board-level complexity is not exposed to MIPS arch layer. So when it is time for a board to die, one does not have to clean up a dozen or so common files like asm/serial.h file. Of course it also offers complete control over the ordering of serial ports to the board. See arch/mips/vr4181/common/serial.c for a simple example of run-time registeration. I believe a couple of other boards are doing this too. Jun
