Re: [RFC][PATCH] Way for platforms to alter built-in serial ports

[Bjorn Helgaas <bjorn.helgaas@hp.com>]

On Wednesday 06 October 2004 1:29 am, Russell King wrote:
> On Thu, Sep 30, 2004 at 10:14:00AM -0600, Bjorn Helgaas wrote:
> > This looks like a reasonable short-term fix, but I think the whole
> > serial8250_isa_init_ports() should go away.  I like dwmw2's suggestion
> > of an 8250_platform.c that could use register_serial() for each port
> > in some platform-supplied old_serial_port[] table, which is probably
> > what you mean by moving to a more dynamic allocation.
> 
> The only reason it exists in its current form is because Alan says
> we can't get rid of the serial port initialisation due to the x86
> requirement for serial console to be initialised reasonably early.
> 
> Unfortunately the early console stuff (afaik) never made it in to
> the kernel, so we've had to keep this hanging around.

My "console=uart" patch
 http://www.ussg.iu.edu/hypermail/linux/kernel/0409.1/1034.html
is a start, I think.  Relative to the current situation, it
 - requires different syntax ("console=uart" vs "console=ttyS0"),
   though a platform could choose to translate "console=ttyS0"
   into "console=uart,io,0x3f8"
 - can start working much earlier (no interrupts or clock
   calibration required)
 - doesn't deal with all the wierd devices the full driver does
 - transitions automatically to the matching ttyS device after
   the driver is initialized