plat_timer_setup, mips_timer_ack, etc.

[Atsushi Nemoto <anemo@mba.ocn.ne.jp>]

With recent clockevent conversion, for typical r4k counter timer,
setup_irq() for the timer interrupt is called three times.

1. from time_init()  (#ifdef CONFIG_IRQ_CPU block)
2. from plat_timer_setup()  (arch/tx4927/common/tx4927_setup.c, for example)
3. from mips_clockevent_init()

Which one should remain?

Also I found mips_timer_ack and cycles_per_jiffy are not used now.
Can we remove them entirely?

Furthermore, I wonder how to disable mips_clockevent_device even if
the CPU has r4k counter.  For example, pnx8550 has the r4k counter but
needs special mips_timer_ack and clocksource_mips.read routine.  I
suppose current time code is broken for such platforms.

Any suggestions?
---
Atsushi Nemoto