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On Mon, Jul 29, 2002 at 10:00:10AM +0100, Russell King wrote: > On Mon, Jul 29, 2002 at 02:08:24PM +1000, David Gibson wrote: > > I've been trying to get the new serial core stuff working on a PPC 4xx > > machine (an EP405 board, specifically). This is proving more > > difficult than I expected.> > It's vital that you mention the kernel version you're using; some of > these problems sound like 2.5.28. Sorry. I'm working off the linuxppc-2.5 BK tree, which is currently at 2.5.29. > > In 8250.c, it appears that in order for a port to be used for the > > serial console it must be defined "old style" with SERIAL_PORT_DFNS, > > rather than being registered with register_serial() (because > > serial8250_console_setup() indexs into the serial8250_ports array)). > > This presents a small problem for 4xx, since it's serial ports are > > memory mapped and the new old_serial_port structure can't represent > > these.> > There is no easy solution for this. Alan said we must not drop support > for serial console initialisation early on in the kernel setup, which > means before the memory subsystems are initialised. > > > I added support for these into 8250.c, but ran into further troubles.> > I suspect a 2.5.28 kernel; please confirm and we'll that it from there. 2.5.29 based BK, actually. > > The current plethora of similar-but-not-the-same structures describing > > serial ports (serial_state, serial_struct, uart_port, old_serial_port) > > is also rather confusing. I'm guessing some of these are deprecated > > and remain only as an aid to transition, but I'm not sure which.> > I don't see there being an easy way to kill this off: > > 1. serial_struct is a userspace API. Ok. > 2. old_serial_port glues asm/serial.h into 8250.c; asm/serial.h can't be > changed because (mainly) ppc uses it elsewhere. Other architectures > seem to do the same sort of thing. I think PPC's use of asm/serial.h in the bootloader needs to go away anyway. Could old_serial_port at least change base_baud to baud_base to match serial_struct and serial_state. That way a designated initializer will work in either context. > Unless ppc and others are willing to put up with major breakage when I > change asm/serial.h, I don't see this getting cleaned up. Comments on > this area welcome. Well, the machines I'm working on are totally broken now, so... -- David Gibson | For every complex problem there is a david@gibson.dropbear.id.au | solution which is simple, neat and | wrong. http://www.ozlabs.org/people/dgibson - 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/ | ||||||||||||
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