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

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

> What I propose is a way for the arch to provide it's own table along
> with the size of it via a function call. It's optional, based on a
> #ifdef defined by the arch in it's asm/serial.h. The only remaining
> tricky point is the fact that you used to size your static array of
> UART's based on the size of the table. So with my path, an arch
> that defines ARCH_HAS_GET_LEGACY_SERIAL_PORTS is supposed to provide
> both the new get_legacy_serial_ports() function, but also to define
> UART_NR to something sensible. I hope one day, we'll be able to
> convert 8250 to more dynamic allocation though.

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.

AFAICS, the only reason for doing serial8250_isa_init_ports() early
is for early serial consoles, and I think those should be done along
the lines of this:
 http://www.ussg.iu.edu/hypermail/linux/kernel/0409.1/1034.html
where the platform can specify a device by its MMIO or IO port address,
and we automatically switch to the corresponding ttyS device later.