This fixes the SH rtc driver to
  (a) correctly report 'enabled' status with other alarm status;
  (b) not duplicate that status in its procfs dump
Signed-off-by: NDavid Brownell <dbrownell@users.sourceforge.net>
Acked-by: NPaul Mundt <lethal@linux-sh.org>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

This adds alarm support for the RTC_ALM_SET, RTC_ALM_READ,
RTC_WKALM_SET and RTC_WKALM_RD operations to rtc-sh.

The only unusual part is the handling of the alarm interrupt. If you
clear the alarm flag (AF) while the time in the RTC still matches the
time in the alarm registers than AF is immediately re-set, and if the
alarm interrupt (AIE) is still enabled then it re-triggers. I was
originally getting around 20k+ interrupts generated during the second
when the RTC and alarm registers matches.

The solution I've used is to clear AIE when the alarm goes off and
then use the carry interrupt to re-enabled it. The carry interrupt
will check AF and re-enabled AIE if it's clear. If AF is not clear
it'll clear it and then the check will be repeated next carry
interrupt. This a bit in rtc structure that indicates that it's
waiting to have AIE re-enabled so it doesn't turn it on when it
wasn't enabled anyway.
Signed-off-by: NJamie Lenehan <lenehan@twibble.org>
Signed-off-by: NPaul Mundt <lethal@linux-sh.org>

The RMONCNT register, which holds the month in the RTC, takes a value
between 1 and 12 while the tm_mon field in the time structures takes
a value between 0 and 11. This wasn't being taken into account in
rtc-sh resulting in the month being out by one.

eg, on my board during boot the RTC is set to:

  RTC is set to Thu Jul 01 09:00:00 1999

but "hwclock -r" immediately after logging in was showing:

  Sun Aug  1 09:01:43 1999  0.000000 seconds
Signed-off-by: NJamie Lenehan <lenehan@twibble.org>
Signed-off-by: NPaul Mundt <lethal@linux-sh.org>

When testing the per second interrupt support (RTC_UIE_ON/RTC_UIE_OFF)
of the new RTC system it would die in sh_rtc_interrupt due to a null
ptr dereference. The following gets it working correctly.
Signed-off-by: NJamie Lenehan <lenehan@twibble.org>
Signed-off-by: NPaul Mundt <lethal@linux-sh.org>

Trivial fixes for build breakage introduced by IRQ handler changes.
Signed-off-by: NPaul Mundt <lethal@linux-sh.org>

Maintain a per-CPU global "struct pt_regs *" variable which can be used instead
of passing regs around manually through all ~1800 interrupt handlers in the
Linux kernel.

The regs pointer is used in few places, but it potentially costs both stack
space and code to pass it around.  On the FRV arch, removing the regs parameter
from all the genirq function results in a 20% speed up of the IRQ exit path
(ie: from leaving timer_interrupt() to leaving do_IRQ()).

Where appropriate, an arch may override the generic storage facility and do
something different with the variable.  On FRV, for instance, the address is
maintained in GR28 at all times inside the kernel as part of general exception
handling.

Having looked over the code, it appears that the parameter may be handed down
through up to twenty or so layers of functions.  Consider a USB character
device attached to a USB hub, attached to a USB controller that posts its
interrupts through a cascaded auxiliary interrupt controller.  A character
device driver may want to pass regs to the sysrq handler through the input
layer which adds another few layers of parameter passing.

I've build this code with allyesconfig for x86_64 and i386.  I've runtested the
main part of the code on FRV and i386, though I can't test most of the drivers.
I've also done partial conversion for powerpc and MIPS - these at least compile
with minimal configurations.

This will affect all archs.  Mostly the changes should be relatively easy.
Take do_IRQ(), store the regs pointer at the beginning, saving the old one:

	struct pt_regs *old_regs = set_irq_regs(regs);

And put the old one back at the end:

	set_irq_regs(old_regs);

Don't pass regs through to generic_handle_irq() or __do_IRQ().

In timer_interrupt(), this sort of change will be necessary:

	-	update_process_times(user_mode(regs));
	-	profile_tick(CPU_PROFILING, regs);
	+	update_process_times(user_mode(get_irq_regs()));
	+	profile_tick(CPU_PROFILING);

I'd like to move update_process_times()'s use of get_irq_regs() into itself,
except that i386, alone of the archs, uses something other than user_mode().

Some notes on the interrupt handling in the drivers:

 (*) input_dev() is now gone entirely.  The regs pointer is no longer stored in
     the input_dev struct.

 (*) finish_unlinks() in drivers/usb/host/ohci-q.c needs checking.  It does
     something different depending on whether it's been supplied with a regs
     pointer or not.

 (*) Various IRQ handler function pointers have been moved to type
     irq_handler_t.
Signed-Off-By: NDavid Howells <dhowells@redhat.com>
(cherry picked from 1b16e7ac850969f38b375e511e3fa2f474a33867 commit)

This replaces the old SH RTC driver, and allows us to
clean quite a lot of things up on the board-specific
side.
Signed-off-by: NPaul Mundt <lethal@linux-sh.org>